NEWS
author wenzelm
Sat Dec 20 11:55:34 2008 +0100 (2008-12-20)
changeset 29145 b1c6f4563df7
parent 29125 d41182a8135c
child 29161 9903e84a9c9c
permissions -rw-r--r--
removed Ids;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Simplified main Isabelle executables, with less surprises on
    10 case-insensitive file-systems (such as Mac OS).
    11 
    12   - The main Isabelle tool wrapper is now called "isabelle" instead of
    13     "isatool."
    14 
    15   - The former "isabelle" alias for "isabelle-process" has been
    16     removed (should rarely occur to regular users).
    17 
    18   - The former "isabelle-interface" and its alias "Isabelle" have been
    19     removed (interfaces are now regular Isabelle tools).
    20 
    21 Within scripts and make files, the Isabelle environment variables
    22 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
    23 respectively.  (The latter are still available as legacy feature.)
    24 
    25 The old isabelle-interface wrapper could react in confusing ways if
    26 the interface was uninstalled or changed otherwise.  Individual
    27 interface tool configuration is now more explicit, see also the
    28 Isabelle system manual.  In particular, Proof General is now available
    29 via "isabelle emacs".
    30 
    31 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
    32 purge installed copies of Isabelle executables and re-run "isabelle
    33 install -p ...", or use symlinks.
    34 
    35 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
    36 old ~/isabelle, which was slightly non-standard and apt cause
    37 surprises on case-insensitive file-systems.
    38 
    39 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
    40 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
    41 care is required when using older releases of Isabelle.  Note that
    42 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
    43 Isabelle distribution.
    44 
    45 * The Isabelle System Manual (system) has been updated, with formally
    46 checked references as hyperlinks.
    47 
    48 * Generalized Isar history, with support for linear undo, direct state
    49 addressing etc.
    50 
    51 * Recovered hiding of consts, which was accidentally broken in
    52 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
    53 makes c inaccessible; consider using ``hide (open) const c'' instead.
    54 
    55 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
    56 interface instead.
    57 
    58 * There is a new lexical item "float" with syntax ["-"] digit+ "." digit+,
    59 without spaces.
    60 
    61 
    62 *** Pure ***
    63 
    64 * Type Binding.T gradually replaces formerly used type bstring for names
    65 to be bound.  Name space interface for declarations has been simplified:
    66 
    67   NameSpace.declare: NameSpace.naming
    68     -> Binding.T -> NameSpace.T -> string * NameSpace.T
    69   NameSpace.bind: NameSpace.naming
    70     -> Binding.T * 'a -> 'a NameSpace.table -> string * 'a NameSpace.table
    71          (*exception Symtab.DUP*)
    72 
    73 See further modules src/Pure/General/binding.ML and
    74 src/Pure/General/name_space.ML
    75 
    76 * Module moves in repository:
    77     src/Pure/Tools/value.ML ~> src/Tools/
    78     src/Pure/Tools/quickcheck.ML ~> src/Tools/
    79 
    80 * Slightly more coherent Pure syntax, with updated documentation in
    81 isar-ref manual.  Removed locales meta_term_syntax and
    82 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
    83 INCOMPATIBILITY in rare situations.
    84 
    85 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
    86 hypotheses.  Sorts required in the course of reasoning need to be
    87 covered by the constraints in the initial statement, completed by the
    88 type instance information of the background theory.  Non-trivial sort
    89 hypotheses, which rarely occur in practice, may be specified via
    90 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
    91 
    92   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
    93 
    94 The result contains an implicit sort hypotheses as before --
    95 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
    96 normalization.
    97 
    98 * Changed defaults for unify configuration options:
    99 
   100   unify_trace_bound = 50 (formerly 25)
   101   unify_search_bound = 60 (formerly 30)
   102 
   103 * Different bookkeeping for code equations:
   104   a) On theory merge, the last set of code equations for a particular constant
   105      is taken (in accordance with the policy applied by other parts of the
   106      code generator framework).
   107   b) Code equations stemming from explicit declarations (e.g. code attribute)
   108      gain priority over default code equations stemming from definition, primrec,
   109      fun etc.
   110   INCOMPATIBILITY.
   111 
   112 * Global versions of theorems stemming from classes do not carry
   113 a parameter prefix any longer.  INCOMPATIBILITY.
   114 
   115 * Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   116 In existing theorem specifications replace the includes element by the
   117 respective context elements of the included locale, omitting those that
   118 are already present in the theorem specification.  Multiple assume
   119 elements of a locale should be replaced by a single one involving the
   120 locale predicate.  In the proof body, declarations (most notably
   121 theorems) may be regained by interpreting the respective locales in the
   122 proof context as required (command "interpret").
   123 If using "includes" in replacement of a target solely because the
   124 parameter types in the theorem are not as general as in the target,
   125 consider declaring a new locale with additional type constraints on the
   126 parameters (context element "constrains").
   127 
   128 * Dropped "locale (open)".  INCOMPATBILITY.
   129 
   130 * Interpretation commands no longer attempt to simplify goal.
   131 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   132 methods intro_locales and unfold_locales to clarify.
   133 
   134 * Interpretation commands no longer accept interpretation attributes.
   135 INCOMPATBILITY.
   136 
   137 * Command 'instance': attached definitions no longer accepted.
   138 INCOMPATIBILITY, use proper 'instantiation' target.
   139 
   140 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   141 
   142 * The 'axiomatization' command now only works within a global theory
   143 context.  INCOMPATIBILITY.
   144 
   145 
   146 *** Document preparation ***
   147 
   148 * Antiquotation @{lemma} now imitates a regular terminal proof,
   149 demanding keyword 'by' and supporting the full method expression
   150 syntax just like the Isar command 'by'.
   151 
   152 
   153 *** HOL ***
   154 
   155 * Made repository layout more coherent with logical
   156 distribution structure:
   157 
   158     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   159     src/HOL/Library/Code_Message.thy ~> src/HOL/
   160     src/HOL/Library/GCD.thy ~> src/HOL/
   161     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   162     src/HOL/Library/Parity.thy ~> src/HOL/
   163     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   164     src/HOL/Real/ContNotDenum.thy ~> src/HOL/
   165     src/HOL/Real/Lubs.thy ~> src/HOL/
   166     src/HOL/Real/PReal.thy ~> src/HOL/
   167     src/HOL/Real/Rational.thy ~> src/HOL/
   168     src/HOL/Real/RComplete.thy ~> src/HOL/
   169     src/HOL/Real/RealDef.thy ~> src/HOL/
   170     src/HOL/Real/RealPow.thy ~> src/HOL/
   171     src/HOL/Real/Real.thy ~> src/HOL/
   172     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   173     src/HOL/Complex/Complex.thy ~> src/HOL/
   174     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/
   175     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   176     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   177     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   178     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   179     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   180     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   181     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   182     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   183     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   184     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   185     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   186     src/HOL/Real/Float ~> src/HOL/Library/
   187 
   188     src/HOL/arith_data.ML ~> src/HOL/Tools
   189     src/HOL/hologic.ML ~> src/HOL/Tools
   190     src/HOL/simpdata.ML ~> src/HOL/Tools
   191     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   192     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   193     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   194     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   195     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   196     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   197     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   198 
   199 * If methods "eval" and "evaluation" encounter a structured proof state
   200 with !!/==>, only the conclusion is evaluated to True (if possible),
   201 avoiding strange error messages.
   202 
   203 * Simplifier: simproc for let expressions now unfolds if bound variable
   204 occurs at most one time in let expression body.  INCOMPATIBILITY.
   205 
   206 * New classes "top" and "bot" with corresponding operations "top" and "bot"
   207 in theory Orderings;  instantiation of class "complete_lattice" requires
   208 instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   209 
   210 * Changed definition lemma "less_fun_def" in order to provide an instance
   211 for preorders on functions;  use lemma "less_le" instead.  INCOMPATIBILITY.
   212 
   213 * Unified theorem tables for both code code generators.  Thus
   214 [code func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   215 
   216 * Constants "undefined" and "default" replace "arbitrary".  Usually
   217 "undefined" is the right choice to replace "arbitrary", though logically
   218 there is no difference.  INCOMPATIBILITY.
   219 
   220 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   221 Posix processes.  Avoids potentially expensive forking of the ML
   222 process.  New thread-based implementation also works on non-Unix
   223 platforms (Cygwin).  Provers are no longer hardwired, but defined
   224 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   225 commands are covered in the isar-ref manual
   226 
   227 * Wrapper scripts for remote SystemOnTPTP service allows to use
   228 sledgehammer without local ATP installation (Vampire etc.).  See also
   229 ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
   230 variable.  Other provers may be included via suitable ML wrappers, see
   231 also src/HOL/ATP_Linkup.thy.
   232 
   233 * Normalization by evaluation now allows non-leftlinear equations.
   234 Declare with attribute [code nbe].
   235 
   236 * Command "value" now integrates different evaluation
   237 mechanisms.  The result of the first successful evaluation mechanism
   238 is printed.  In square brackets a particular named evaluation
   239 mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
   240 further src/HOL/ex/Eval_Examples.thy.
   241 
   242 * New method "sizechange" to automate termination proofs using (a
   243 modification of) the size-change principle. Requires SAT solver.
   244 
   245 * HOL/Orderings: class "wellorder" moved here, with explicit induction
   246 rule "less_induct" as assumption.  For instantiation of "wellorder" by
   247 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
   248 
   249 * HOL/Orderings: added class "preorder" as superclass of "order".
   250 INCOMPATIBILITY: Instantiation proofs for order, linorder
   251 etc. slightly changed.  Some theorems named order_class.* now named
   252 preorder_class.*.
   253 
   254 * HOL/Finite_Set: added a new fold combinator of type
   255   ('a => 'b => 'b) => 'b => 'a set => 'b
   256 Occasionally this is more convenient than the old fold combinator which is
   257 now defined in terms of the new one and renamed to fold_image.
   258 
   259 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
   260 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   261 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   262 of lemmas from Divides has been generalized from nat to class
   263 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   264 renames resulting from duplicate elimination:
   265 
   266     dvd_def_mod ~>          dvd_eq_mod_eq_0
   267     zero_dvd_iff ~>         dvd_0_left_iff
   268     dvd_0 ~>                dvd_0_right
   269     DIVISION_BY_ZERO_DIV ~> div_by_0
   270     DIVISION_BY_ZERO_MOD ~> mod_by_0
   271     mult_div ~>             div_mult_self2_is_id
   272     mult_mod ~>             mod_mult_self2_is_0
   273 
   274 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   275 zlcm (for int); carried together from various gcd/lcm developements in
   276 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
   277 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
   278 recover tupled syntax, use syntax declarations like:
   279 
   280     hide (open) const gcd
   281     abbreviation gcd where
   282       "gcd == (%(a, b). GCD.gcd a b)"
   283     notation (output)
   284       GCD.gcd ("gcd '(_, _')")
   285 
   286 (analogously for lcm, zgcd, zlcm).
   287 
   288 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   289 
   290 * The real numbers offer decimal input syntax: 12.34 is translated into
   291   1234/10^4. This translation is not reversed upon output.
   292 
   293 * New ML antiquotation @{code}: takes constant as argument, generates
   294 corresponding code in background and inserts name of the corresponding
   295 resulting ML value/function/datatype constructor binding in place.
   296 All occurrences of @{code} with a single ML block are generated
   297 simultaneously.  Provides a generic and safe interface for
   298 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
   299 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
   300 application.  In future you ought refrain from ad-hoc compiling
   301 generated SML code on the ML toplevel.  Note that (for technical
   302 reasons) @{code} cannot refer to constants for which user-defined
   303 serializations are set.  Refer to the corresponding ML counterpart
   304 directly in that cases.
   305 
   306 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   307 Complex_Main.thy remain as they are.
   308 
   309 * New image HOL-Plain provides a minimal HOL with the most important
   310 tools available (inductive, datatype, primrec, ...).  By convention
   311 the corresponding theory Plain should be ancestor of every further
   312 (library) theory.  Some library theories now have ancestor Plain
   313 (instead of Main), thus theory Main occasionally has to be imported
   314 explicitly.
   315 
   316 * The metis method now fails in the usual manner, rather than raising
   317 an exception, if it determines that it cannot prove the theorem.
   318 
   319 * The metis method no longer fails because the theorem is too trivial
   320 (contains the empty clause).
   321 
   322 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   323 as the structured Isar versions "cases" and "induct", cf. the
   324 corresponding "cases" and "induct" attributes.  Mutual induction rules
   325 are now presented as a list of individual projections
   326 (e.g. foo_bar.inducts for types foo and bar); the old format with
   327 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   328 rare situations a different rule is selected --- notably nested tuple
   329 elimination instead of former prod.exhaust: use explicit (case_tac t
   330 rule: prod.exhaust) here.
   331 
   332 * Attributes "cases", "induct", "coinduct" support "del" option.
   333 
   334 * Removed fact "case_split_thm", which duplicates "case_split".
   335 
   336 * Command 'rep_datatype': instead of theorem names the command now
   337 takes a list of terms denoting the constructors of the type to be
   338 represented as datatype.  The characteristic theorems have to be
   339 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   340 have disappeared in favour of existing ones:
   341 
   342     unit_induct                 ~> unit.induct
   343     prod_induct                 ~> prod.induct
   344     sum_induct                  ~> sum.induct
   345     Suc_Suc_eq                  ~> nat.inject
   346     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   347 
   348 * Library/Nat_Infinity: added addition, numeral syntax and more
   349 instantiations for algebraic structures.  Removed some duplicate
   350 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   351 
   352 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   353 menu.
   354 
   355 
   356 *** HOL-Algebra ***
   357 
   358 * New locales for orders and lattices where the equivalence relation
   359   is not restricted to equality.  INCOMPATIBILITY: all order and
   360   lattice locales use a record structure with field eq for the
   361   equivalence.
   362 
   363 * New theory of factorial domains.
   364 
   365 * Units_l_inv and Units_r_inv are now simprules by default.
   366 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   367 and/or r_inv will now also require deletion of these lemmas.
   368 
   369 * Renamed the following theorems.  INCOMPATIBILITY.
   370 UpperD ~> Upper_memD
   371 LowerD ~> Lower_memD
   372 least_carrier ~> least_closed
   373 greatest_carrier ~> greatest_closed
   374 greatest_Lower_above ~> greatest_Lower_below
   375 one_zero ~> carrier_one_zero
   376 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   377 
   378 
   379 *** HOL-NSA ***
   380 
   381 * Created new image HOL-NSA, containing theories of nonstandard
   382 analysis which were previously part of HOL-Complex.  Entry point
   383 Hyperreal.thy remains valid, but theories formerly using
   384 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   385 
   386 
   387 *** ZF ***
   388 
   389 * Proof of Zorn's Lemma for partial orders.
   390 
   391 
   392 *** ML ***
   393 
   394 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   395 to 'a -> thm, while results are always tagged with an authentic oracle
   396 name.  The Isar command 'oracle' is now polymorphic, no argument type
   397 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   398 accordingly.  Note that extra performance may be gained by producing
   399 the cterm carefully, avoiding slow Thm.cterm_of.
   400 
   401 * ML bindings produced via Isar commands are stored within the Isar
   402 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   403 become thread-safe and work with undo as expected (concerning
   404 top-level bindings, not side-effects on global references).
   405 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   406 compiler at runtime; really global bindings need to be given outside a
   407 theory. [Poly/ML 5.2 or later]
   408 
   409 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   410 context. Top-level ML bindings are stored within the proof context in
   411 a purely sequential fashion, disregarding the nested proof structure.
   412 ML bindings introduced by 'ML_prf' are discarded at the end of the
   413 proof.  [Poly/ML 5.2 or later]
   414 
   415 * Generic Toplevel.add_hook interface allows to analyze the result of
   416 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   417 for theorem dependency output of transactions resulting in a new
   418 theory state.
   419 
   420 * Name bindings in higher specification mechanisms (notably
   421 LocalTheory.define, LocalTheory.note, and derived packages) are now
   422 formalized as type Name.binding, replacing old bstring.
   423 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   424 also Name.name_of.  Packages should pass name bindings given by the
   425 user to underlying specification mechanisms; this enables precise
   426 tracking of source positions, for example.
   427 
   428 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   429 LocalTheory.note etc.) now refer to the *full* internal name, not the
   430 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   431 
   432 * Rules and tactics that read instantiations (read_instantiate,
   433 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   434 context, which is required for parsing and type-checking.  Moreover,
   435 the variables are specified as plain indexnames, not string encodings
   436 thereof.  INCOMPATIBILITY.
   437 
   438 * Disposed old type and term read functions (Sign.read_def_typ,
   439 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   440 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   441 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   442 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   443 resort for legacy applications.
   444 
   445 * Antiquotations: block-structured compilation context indicated by
   446 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   447 
   448   @{let ?pat = term}                      - term abbreviation (HO matching)
   449   @{note name = fact}                     - fact abbreviation
   450   @{thm fact}                             - singleton fact (with attributes)
   451   @{thms fact}                            - general fact (with attributes)
   452   @{lemma prop by method}                 - singleton goal
   453   @{lemma prop by meth1 meth2}            - singleton goal
   454   @{lemma prop1 ... propN by method}      - general goal
   455   @{lemma prop1 ... propN by meth1 meth2} - general goal
   456   @{lemma (open) ...}                     - open derivation
   457 
   458 
   459 *** System ***
   460 
   461 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   462 Poly/ML 5.2.1 or later.
   463 
   464 * The Isabelle "emacs" tool provides a specific interface to invoke
   465 Proof General / Emacs, with more explicit failure if that is not
   466 installed (the old isabelle-interface script silently falls back on
   467 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   468 installation location of the Proof General distribution.
   469 
   470 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   471 the Isabelle process into a JVM/Scala application.  See
   472 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   473 process wrapper has been discontinued.)
   474 
   475 * Status messages (with exact source position information) are
   476 emitted, if proper markup print mode is enabled.  This allows
   477 user-interface components to provide detailed feedback on internal
   478 prover operations.
   479 
   480 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   481 
   482 
   483 
   484 New in Isabelle2008 (June 2008)
   485 -------------------------------
   486 
   487 *** General ***
   488 
   489 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   490 and updated, with formally checked references as hyperlinks.
   491 
   492 * Theory loader: use_thy (and similar operations) no longer set the
   493 implicit ML context, which was occasionally hard to predict and in
   494 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   495 provides a proper context already.
   496 
   497 * Theory loader: old-style ML proof scripts being *attached* to a thy
   498 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   499 'use' within a theory file will do the job.
   500 
   501 * Name space merge now observes canonical order, i.e. the second space
   502 is inserted into the first one, while existing entries in the first
   503 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   504 swap theory imports.
   505 
   506 * Syntax: symbol \<chi> is now considered a letter.  Potential
   507 INCOMPATIBILITY in identifier syntax etc.
   508 
   509 * Outer syntax: string tokens no longer admit escaped white space,
   510 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   511 white space without escapes.
   512 
   513 * Outer syntax: string tokens may contain arbitrary character codes
   514 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   515 "foo_bar".
   516 
   517 
   518 *** Pure ***
   519 
   520 * Context-dependent token translations.  Default setup reverts locally
   521 fixed variables, and adds hilite markup for undeclared frees.
   522 
   523 * Unused theorems can be found using the new command 'unused_thms'.
   524 There are three ways of invoking it:
   525 
   526 (1) unused_thms
   527      Only finds unused theorems in the current theory.
   528 
   529 (2) unused_thms thy_1 ... thy_n -
   530      Finds unused theorems in the current theory and all of its ancestors,
   531      excluding the theories thy_1 ... thy_n and all of their ancestors.
   532 
   533 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   534      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   535      their ancestors, excluding the theories thy_1 ... thy_n and all of
   536      their ancestors.
   537 
   538 In order to increase the readability of the list produced by
   539 unused_thms, theorems that have been created by a particular instance
   540 of a theory command such as 'inductive' or 'function' are considered
   541 to belong to the same "group", meaning that if at least one theorem in
   542 this group is used, the other theorems in the same group are no longer
   543 reported as unused.  Moreover, if all theorems in the group are
   544 unused, only one theorem in the group is displayed.
   545 
   546 Note that proof objects have to be switched on in order for
   547 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   548 usually the case when using Proof General with the default settings).
   549 
   550 * Authentic naming of facts disallows ad-hoc overwriting of previous
   551 theorems within the same name space.  INCOMPATIBILITY, need to remove
   552 duplicate fact bindings, or even accidental fact duplications.  Note
   553 that tools may maintain dynamically scoped facts systematically, using
   554 PureThy.add_thms_dynamic.
   555 
   556 * Command 'hide' now allows to hide from "fact" name space as well.
   557 
   558 * Eliminated destructive theorem database, simpset, claset, and
   559 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   560 update of theories within ML code.
   561 
   562 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   563 INCOMPATIBILITY, object-logics depending on former Pure require
   564 additional setup PureThy.old_appl_syntax_setup; object-logics
   565 depending on former CPure need to refer to Pure.
   566 
   567 * Commands 'use' and 'ML' are now purely functional, operating on
   568 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   569 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   570 INCOMPATIBILITY.
   571 
   572 * Command 'setup': discontinued implicit version with ML reference.
   573 
   574 * Instantiation target allows for simultaneous specification of class
   575 instance operations together with an instantiation proof.
   576 Type-checking phase allows to refer to class operations uniformly.
   577 See src/HOL/Complex/Complex.thy for an Isar example and
   578 src/HOL/Library/Eval.thy for an ML example.
   579 
   580 * Indexing of literal facts: be more serious about including only
   581 facts from the visible specification/proof context, but not the
   582 background context (locale etc.).  Affects `prop` notation and method
   583 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   584 situations.
   585 
   586 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   587 "(open)" option, which used to expose internal bound variables to the
   588 proof text.
   589 
   590 * Isar statements: removed obsolete case "rule_context".
   591 INCOMPATIBILITY, better use explicit fixes/assumes.
   592 
   593 * Locale proofs: default proof step now includes 'unfold_locales';
   594 hence 'proof' without argument may be used to unfold locale
   595 predicates.
   596 
   597 
   598 *** Document preparation ***
   599 
   600 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   601 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   602 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   603 spot); renamed link color from "darkblue" to "linkcolor" (default
   604 value unchanged, can be redefined via \definecolor); no longer sets
   605 "a4paper" option (unnecessary or even intrusive).
   606 
   607 * Antiquotation @{lemma A method} proves proposition A by the given
   608 method (either a method name or a method name plus (optional) method
   609 arguments in parentheses) and prints A just like @{prop A}.
   610 
   611 
   612 *** HOL ***
   613 
   614 * New primrec package.  Specification syntax conforms in style to
   615 definition/function/....  No separate induction rule is provided.  The
   616 "primrec" command distinguishes old-style and new-style specifications
   617 by syntax.  The former primrec package is now named OldPrimrecPackage.
   618 When adjusting theories, beware: constants stemming from new-style
   619 primrec specifications have authentic syntax.
   620 
   621 * Metis prover is now an order of magnitude faster, and also works
   622 with multithreading.
   623 
   624 * Metis: the maximum number of clauses that can be produced from a
   625 theorem is now given by the attribute max_clauses.  Theorems that
   626 exceed this number are ignored, with a warning printed.
   627 
   628 * Sledgehammer no longer produces structured proofs by default. To
   629 enable, declare [[sledgehammer_full = true]].  Attributes
   630 reconstruction_modulus, reconstruction_sorts renamed
   631 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   632 
   633 * Method "induct_scheme" derives user-specified induction rules
   634 from well-founded induction and completeness of patterns. This factors
   635 out some operations that are done internally by the function package
   636 and makes them available separately.  See
   637 src/HOL/ex/Induction_Scheme.thy for examples.
   638 
   639 * More flexible generation of measure functions for termination
   640 proofs: Measure functions can be declared by proving a rule of the
   641 form "is_measure f" and giving it the [measure_function] attribute.
   642 The "is_measure" predicate is logically meaningless (always true), and
   643 just guides the heuristic.  To find suitable measure functions, the
   644 termination prover sets up the goal "is_measure ?f" of the appropriate
   645 type and generates all solutions by prolog-style backwards proof using
   646 the declared rules.
   647 
   648 This setup also deals with rules like 
   649 
   650   "is_measure f ==> is_measure (list_size f)"
   651 
   652 which accommodates nested datatypes that recurse through lists.
   653 Similar rules are predeclared for products and option types.
   654 
   655 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   656 
   657   INCOMPATIBILITIES:
   658 
   659   - Definitions of overloaded constants on sets have to be replaced by
   660     definitions on => and bool.
   661 
   662   - Some definitions of overloaded operators on sets can now be proved
   663     using the definitions of the operators on => and bool.  Therefore,
   664     the following theorems have been renamed:
   665 
   666       subset_def   -> subset_eq
   667       psubset_def  -> psubset_eq
   668       set_diff_def -> set_diff_eq
   669       Compl_def    -> Compl_eq
   670       Sup_set_def  -> Sup_set_eq
   671       Inf_set_def  -> Inf_set_eq
   672       sup_set_def  -> sup_set_eq
   673       inf_set_def  -> inf_set_eq
   674 
   675   - Due to the incompleteness of the HO unification algorithm, some
   676     rules such as subst may require manual instantiation, if some of
   677     the unknowns in the rule is a set.
   678 
   679   - Higher order unification and forward proofs:
   680     The proof pattern
   681 
   682       have "P (S::'a set)" <...>
   683       then have "EX S. P S" ..
   684 
   685     no longer works (due to the incompleteness of the HO unification
   686     algorithm) and must be replaced by the pattern
   687 
   688       have "EX S. P S"
   689       proof
   690         show "P S" <...>
   691       qed
   692 
   693   - Calculational reasoning with subst (or similar rules):
   694     The proof pattern
   695 
   696       have "P (S::'a set)" <...>
   697       also have "S = T" <...>
   698       finally have "P T" .
   699 
   700     no longer works (for similar reasons as the previous example) and
   701     must be replaced by something like
   702 
   703       have "P (S::'a set)" <...>
   704       moreover have "S = T" <...>
   705       ultimately have "P T" by simp
   706 
   707   - Tactics or packages written in ML code:
   708     Code performing pattern matching on types via
   709 
   710       Type ("set", [T]) => ...
   711 
   712     must be rewritten. Moreover, functions like strip_type or
   713     binder_types no longer return the right value when applied to a
   714     type of the form
   715 
   716       T1 => ... => Tn => U => bool
   717 
   718     rather than
   719 
   720       T1 => ... => Tn => U set
   721 
   722 * Merged theories Wellfounded_Recursion, Accessible_Part and
   723 Wellfounded_Relations to theory Wellfounded.
   724 
   725 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   726 
   727 * Class finite no longer treats UNIV as class parameter.  Use class
   728 enum from theory Library/Enum instead to achieve a similar effect.
   729 INCOMPATIBILITY.
   730 
   731 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   732 and "Cons".  INCOMPATIBILITY.
   733 
   734 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   735 Potential INCOMPATIBILITY.
   736 
   737 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   738 injective_fst_snd removed, use split_eta and prod_eqI instead.
   739 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   740 
   741 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   742 the same name in theory Orderings:
   743 
   744   less_trans
   745   less_linear
   746   le_imp_less_or_eq
   747   le_less_trans
   748   less_le_trans
   749   less_not_sym
   750   less_asym
   751 
   752 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   753 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   754 and different variable names.
   755 
   756 * Library/Option_ord.thy: Canonical order on option type.
   757 
   758 * Library/RBT.thy: Red-black trees, an efficient implementation of
   759 finite maps.
   760 
   761 * Library/Countable.thy: Type class for countable types.
   762 
   763 * Theory Int: The representation of numerals has changed.  The infix
   764 operator BIT and the bit datatype with constructors B0 and B1 have
   765 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   766 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   767 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   768 accordingly.
   769 
   770 * Theory Nat: definition of <= and < on natural numbers no longer
   771 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   772 le_def and less_def have disappeared.  Consider lemmas not_less
   773 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   774 
   775 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   776 (whose purpose mainly is for various fold_set functionals) have been
   777 abandoned in favor of the existing algebraic classes
   778 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   779 lower_semilattice (resp. upper_semilattice) and linorder.
   780 INCOMPATIBILITY.
   781 
   782 * Theory Transitive_Closure: induct and cases rules now declare proper
   783 case_names ("base" and "step").  INCOMPATIBILITY.
   784 
   785 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   786 lattices.  The form set-specific version is available as
   787 Inductive.lfp_ordinal_induct_set.
   788 
   789 * Renamed theorems "power.simps" to "power_int.simps".
   790 INCOMPATIBILITY.
   791 
   792 * Class semiring_div provides basic abstract properties of semirings
   793 with division and modulo operations.  Subsumes former class dvd_mod.
   794 
   795 * Merged theories IntDef, Numeral and IntArith into unified theory
   796 Int.  INCOMPATIBILITY.
   797 
   798 * Theory Library/Code_Index: type "index" now represents natural
   799 numbers rather than integers.  INCOMPATIBILITY.
   800 
   801 * New class "uminus" with operation "uminus" (split of from class
   802 "minus" which now only has operation "minus", binary).
   803 INCOMPATIBILITY.
   804 
   805 * Constants "card", "internal_split", "option_map" now with authentic
   806 syntax.  INCOMPATIBILITY.
   807 
   808 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   809 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   810 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   811 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   812 Sup_set_def, le_def, less_def, option_map_def now with object
   813 equality.  INCOMPATIBILITY.
   814 
   815 * Records. Removed K_record, and replaced it by pure lambda term
   816 %x. c. The simplifier setup is now more robust against eta expansion.
   817 INCOMPATIBILITY: in cases explicitly referring to K_record.
   818 
   819 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   820 
   821 * Library/ListVector: new theory of arithmetic vector operations.
   822 
   823 * Library/Order_Relation: new theory of various orderings as sets of
   824 pairs.  Defines preorders, partial orders, linear orders and
   825 well-orders on sets and on types.
   826 
   827 
   828 *** ZF ***
   829 
   830 * Renamed some theories to allow to loading both ZF and HOL in the
   831 same session:
   832 
   833   Datatype  -> Datatype_ZF
   834   Inductive -> Inductive_ZF
   835   Int       -> Int_ZF
   836   IntDiv    -> IntDiv_ZF
   837   Nat       -> Nat_ZF
   838   List      -> List_ZF
   839   Main      -> Main_ZF
   840 
   841 INCOMPATIBILITY: ZF theories that import individual theories below
   842 Main might need to be adapted.  Regular theory Main is still
   843 available, as trivial extension of Main_ZF.
   844 
   845 
   846 *** ML ***
   847 
   848 * ML within Isar: antiquotation @{const name} or @{const
   849 name(typargs)} produces statically-checked Const term.
   850 
   851 * Functor NamedThmsFun: data is available to the user as dynamic fact
   852 (of the same name).  Removed obsolete print command.
   853 
   854 * Removed obsolete "use_legacy_bindings" function.
   855 
   856 * The ``print mode'' is now a thread-local value derived from a global
   857 template (the former print_mode reference), thus access becomes
   858 non-critical.  The global print_mode reference is for session
   859 management only; user-code should use print_mode_value,
   860 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   861 
   862 * Functions system/system_out provide a robust way to invoke external
   863 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   864 Do not use OS.Process.system etc. from the basis library!
   865 
   866 
   867 *** System ***
   868 
   869 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   870 in accordance with Proof General 3.7, which prefers GNU emacs.
   871 
   872 * isatool tty runs Isabelle process with plain tty interaction;
   873 optional line editor may be specified via ISABELLE_LINE_EDITOR
   874 setting, the default settings attempt to locate "ledit" and "rlwrap".
   875 
   876 * isatool browser now works with Cygwin as well, using general
   877 "javapath" function defined in Isabelle process environment.
   878 
   879 * YXML notation provides a simple and efficient alternative to
   880 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   881 isatool yxml as described in the Isabelle system manual.
   882 
   883 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   884 provides general wrapper for managing an Isabelle process in a robust
   885 fashion, with ``cooked'' output from stdin/stderr.
   886 
   887 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   888 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   889 
   890 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   891 way of changing the user's settings is via
   892 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   893 script.
   894 
   895 * Multithreading.max_threads := 0 refers to the number of actual CPU
   896 cores of the underlying machine, which is a good starting point for
   897 optimal performance tuning.  The corresponding usedir option -M allows
   898 "max" as an alias for "0".  WARNING: does not work on certain versions
   899 of Mac OS (with Poly/ML 5.1).
   900 
   901 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   902 adverse effect of Isabelle flooding interactive front-ends (notably
   903 ProofGeneral / XEmacs).
   904 
   905 
   906 
   907 New in Isabelle2007 (November 2007)
   908 -----------------------------------
   909 
   910 *** General ***
   911 
   912 * More uniform information about legacy features, notably a
   913 warning/error of "Legacy feature: ...", depending on the state of the
   914 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   915 legacy features will disappear eventually.
   916 
   917 * Theory syntax: the header format ``theory A = B + C:'' has been
   918 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   919 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   920 
   921 * Theory syntax: the old non-Isar theory file format has been
   922 discontinued altogether.  Note that ML proof scripts may still be used
   923 with Isar theories; migration is usually quite simple with the ML
   924 function use_legacy_bindings.  INCOMPATIBILITY.
   925 
   926 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   927 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   928 quotes.
   929 
   930 * Theory loader: be more serious about observing the static theory
   931 header specifications (including optional directories), but not the
   932 accidental file locations of previously successful loads.  The strict
   933 update policy of former update_thy is now already performed by
   934 use_thy, so the former has been removed; use_thys updates several
   935 theories simultaneously, just as 'imports' within a theory header
   936 specification, but without merging the results.  Potential
   937 INCOMPATIBILITY: may need to refine theory headers and commands
   938 ROOT.ML which depend on load order.
   939 
   940 * Theory loader: optional support for content-based file
   941 identification, instead of the traditional scheme of full physical
   942 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   943 (cf. the system manual).  The new scheme allows to work with
   944 non-finished theories in persistent session images, such that source
   945 files may be moved later on without requiring reloads.
   946 
   947 * Theory loader: old-style ML proof scripts being *attached* to a thy
   948 file (with the same base name as the theory) are considered a legacy
   949 feature, which will disappear eventually. Even now, the theory loader
   950 no longer maintains dependencies on such files.
   951 
   952 * Syntax: the scope for resolving ambiguities via type-inference is
   953 now limited to individual terms, instead of whole simultaneous
   954 specifications as before. This greatly reduces the complexity of the
   955 syntax module and improves flexibility by separating parsing and
   956 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   957 'fixes' etc.) are required in rare situations.
   958 
   959 * Syntax: constants introduced by new-style packages ('definition',
   960 'abbreviation' etc.) are passed through the syntax module in
   961 ``authentic mode''. This means that associated mixfix annotations
   962 really stick to such constants, independently of potential name space
   963 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   964 trees are represented slightly differently, may need to adapt syntax
   965 translations accordingly. Use CONST marker in 'translations' and
   966 @{const_syntax} antiquotation in 'parse_translation' etc.
   967 
   968 * Legacy goal package: reduced interface to the bare minimum required
   969 to keep existing proof scripts running.  Most other user-level
   970 functions are now part of the OldGoals structure, which is *not* open
   971 by default (consider isatool expandshort before open OldGoals).
   972 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   973 these tend to cause confusion about the actual goal (!) context being
   974 used here, which is not necessarily the same as the_context().
   975 
   976 * Command 'find_theorems': supports "*" wild-card in "name:"
   977 criterion; "with_dups" option.  Certain ProofGeneral versions might
   978 support a specific search form (see ProofGeneral/CHANGES).
   979 
   980 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   981 by default, which means that "prems" (and also "fixed variables") are
   982 suppressed from proof state output.  Note that the ProofGeneral
   983 settings mechanism allows to change and save options persistently, but
   984 older versions of Isabelle will fail to start up if a negative prems
   985 limit is imposed.
   986 
   987 * Local theory targets may be specified by non-nested blocks of
   988 ``context/locale/class ... begin'' followed by ``end''.  The body may
   989 contain definitions, theorems etc., including any derived mechanism
   990 that has been implemented on top of these primitives.  This concept
   991 generalizes the existing ``theorem (in ...)'' towards more versatility
   992 and scalability.
   993 
   994 * Proof General interface: proper undo of final 'end' command;
   995 discontinued Isabelle/classic mode (ML proof scripts).
   996 
   997 
   998 *** Document preparation ***
   999 
  1000 * Added antiquotation @{theory name} which prints the given name,
  1001 after checking that it refers to a valid ancestor theory in the
  1002 current context.
  1003 
  1004 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1005 check the given source text as ML type/structure, printing verbatim.
  1006 
  1007 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1008 "c args == rhs" given in the current context.  (Any number of
  1009 arguments may be given on the LHS.)
  1010 
  1011 
  1012 *** Pure ***
  1013 
  1014 * The 'class' package offers a combination of axclass and locale to
  1015 achieve Haskell-like type classes in Isabelle.  Definitions and
  1016 theorems within a class context produce both relative results (with
  1017 implicit parameters according to the locale context), and polymorphic
  1018 constants with qualified polymorphism (according to the class
  1019 context).  Within the body context of a 'class' target, a separate
  1020 syntax layer ("user space type system") takes care of converting
  1021 between global polymorphic consts and internal locale representation.
  1022 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1023 "isatool doc classes" provides a tutorial.
  1024 
  1025 * Generic code generator framework allows to generate executable
  1026 code for ML and Haskell (including Isabelle classes).  A short usage
  1027 sketch:
  1028 
  1029     internal compilation:
  1030         export_code <list of constants (term syntax)> in SML
  1031     writing SML code to a file:
  1032         export_code <list of constants (term syntax)> in SML <filename>
  1033     writing OCaml code to a file:
  1034         export_code <list of constants (term syntax)> in OCaml <filename>
  1035     writing Haskell code to a bunch of files:
  1036         export_code <list of constants (term syntax)> in Haskell <filename>
  1037 
  1038     evaluating closed propositions to True/False using code generation:
  1039         method ``eval''
  1040 
  1041 Reasonable default setup of framework in HOL.
  1042 
  1043 Theorem attributs for selecting and transforming function equations theorems:
  1044 
  1045     [code fun]:        select a theorem as function equation for a specific constant
  1046     [code fun del]:    deselect a theorem as function equation for a specific constant
  1047     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1048     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1049 
  1050 User-defined serializations (target in {SML, OCaml, Haskell}):
  1051 
  1052     code_const <and-list of constants (term syntax)>
  1053       {(target) <and-list of const target syntax>}+
  1054 
  1055     code_type <and-list of type constructors>
  1056       {(target) <and-list of type target syntax>}+
  1057 
  1058     code_instance <and-list of instances>
  1059       {(target)}+
  1060         where instance ::= <type constructor> :: <class>
  1061 
  1062     code_class <and_list of classes>
  1063       {(target) <and-list of class target syntax>}+
  1064         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1065 
  1066 code_instance and code_class only are effective to target Haskell.
  1067 
  1068 For example usage see src/HOL/ex/Codegenerator.thy and
  1069 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1070 generation from Isabelle/HOL theories is available via "isatool doc
  1071 codegen".
  1072 
  1073 * Code generator: consts in 'consts_code' Isar commands are now
  1074 referred to by usual term syntax (including optional type
  1075 annotations).
  1076 
  1077 * Command 'no_translations' removes translation rules from theory
  1078 syntax.
  1079 
  1080 * Overloaded definitions are now actually checked for acyclic
  1081 dependencies.  The overloading scheme is slightly more general than
  1082 that of Haskell98, although Isabelle does not demand an exact
  1083 correspondence to type class and instance declarations.
  1084 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1085 exotic versions of overloading -- at the discretion of the user!
  1086 
  1087 Polymorphic constants are represented via type arguments, i.e. the
  1088 instantiation that matches an instance against the most general
  1089 declaration given in the signature.  For example, with the declaration
  1090 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1091 as c(nat).  Overloading is essentially simultaneous structural
  1092 recursion over such type arguments.  Incomplete specification patterns
  1093 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1094 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1095 Command 'print_theory' outputs the normalized system of recursive
  1096 equations, see section "definitions".
  1097 
  1098 * Configuration options are maintained within the theory or proof
  1099 context (with name and type bool/int/string), providing a very simple
  1100 interface to a poor-man's version of general context data.  Tools may
  1101 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1102 these values using Config.get etc.  Users may change options via an
  1103 associated attribute of the same name.  This form of context
  1104 declaration works particularly well with commands 'declare' or
  1105 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1106 very easy to avoid global references, which would not observe Isar
  1107 toplevel undo/redo and fail to work with multithreading.
  1108 
  1109 Various global ML references of Pure and HOL have been turned into
  1110 configuration options:
  1111 
  1112   Unify.search_bound		unify_search_bound
  1113   Unify.trace_bound		unify_trace_bound
  1114   Unify.trace_simp		unify_trace_simp
  1115   Unify.trace_types		unify_trace_types
  1116   Simplifier.simp_depth_limit	simp_depth_limit
  1117   Blast.depth_limit		blast_depth_limit
  1118   DatatypeProp.dtK		datatype_distinctness_limit
  1119   fast_arith_neq_limit  	fast_arith_neq_limit
  1120   fast_arith_split_limit	fast_arith_split_limit
  1121 
  1122 * Named collections of theorems may be easily installed as context
  1123 data using the functor NamedThmsFun (see also
  1124 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1125 attributes; there is also a toplevel print command.  This facility is
  1126 just a common case of general context data, which is the preferred way
  1127 for anything more complex than just a list of facts in canonical
  1128 order.
  1129 
  1130 * Isar: command 'declaration' augments a local theory by generic
  1131 declaration functions written in ML.  This enables arbitrary content
  1132 being added to the context, depending on a morphism that tells the
  1133 difference of the original declaration context wrt. the application
  1134 context encountered later on.
  1135 
  1136 * Isar: proper interfaces for simplification procedures.  Command
  1137 'simproc_setup' declares named simprocs (with match patterns, and body
  1138 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1139 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1140 
  1141 * Isar: an extra pair of brackets around attribute declarations
  1142 abbreviates a theorem reference involving an internal dummy fact,
  1143 which will be ignored later --- only the effect of the attribute on
  1144 the background context will persist.  This form of in-place
  1145 declarations is particularly useful with commands like 'declare' and
  1146 'using', for example ``have A using [[simproc a]] by simp''.
  1147 
  1148 * Isar: method "assumption" (and implicit closing of subproofs) now
  1149 takes simple non-atomic goal assumptions into account: after applying
  1150 an assumption as a rule the resulting subgoals are solved by atomic
  1151 assumption steps.  This is particularly useful to finish 'obtain'
  1152 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1153 without referring to the original premise "!!x. P x ==> thesis" in the
  1154 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1155 more permissive.
  1156 
  1157 * Isar: implicit use of prems from the Isar proof context is
  1158 considered a legacy feature.  Common applications like ``have A .''
  1159 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1160 referencing facts explicitly here improves readability and
  1161 maintainability of proof texts.
  1162 
  1163 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1164 the obtained context from the course of reasoning!  For example:
  1165 
  1166   assume "EX x y. A x & B y"   -- "any previous fact"
  1167   then guess x and y by clarify
  1168 
  1169 This technique is potentially adventurous, depending on the facts and
  1170 proof tools being involved here.
  1171 
  1172 * Isar: known facts from the proof context may be specified as literal
  1173 propositions, using ASCII back-quote syntax.  This works wherever
  1174 named facts used to be allowed so far, in proof commands, proof
  1175 methods, attributes etc.  Literal facts are retrieved from the context
  1176 according to unification of type and term parameters.  For example,
  1177 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1178 theorems in the current context, then these are valid literal facts:
  1179 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1180 
  1181 There is also a proof method "fact" which does the same composition
  1182 for explicit goal states, e.g. the following proof texts coincide with
  1183 certain special cases of literal facts:
  1184 
  1185   have "A" by fact                 ==  note `A`
  1186   have "A ==> B" by fact           ==  note `A ==> B`
  1187   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1188   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1189 
  1190 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1191 outer syntax.  Thus symbolic identifiers may be used without
  1192 additional white space in declarations like this: ``assume *: A''.
  1193 
  1194 * Isar: 'print_facts' prints all local facts of the current context,
  1195 both named and unnamed ones.
  1196 
  1197 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1198 
  1199   def x == "t" and y == "u"
  1200 
  1201 * Isar: added command 'unfolding', which is structurally similar to
  1202 'using', but affects both the goal state and facts by unfolding given
  1203 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1204 'unfolded' attribute may be replaced by first-class proof text.
  1205 
  1206 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1207 and command 'unfolding' now all support object-level equalities
  1208 (potentially conditional).  The underlying notion of rewrite rule is
  1209 analogous to the 'rule_format' attribute, but *not* that of the
  1210 Simplifier (which is usually more generous).
  1211 
  1212 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1213 premises of a theorem by n. Useful in conjunction with drule.
  1214 
  1215 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1216 method expression within a sandbox consisting of the first N
  1217 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1218 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1219 simplifies all new goals that emerge from applying rule foo to the
  1220 originally first one.
  1221 
  1222 * Isar: schematic goals are no longer restricted to higher-order
  1223 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1224 expected.
  1225 
  1226 * Isar: the conclusion of a long theorem statement is now either
  1227 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1228 (essentially a disjunction of cases with local parameters and
  1229 assumptions).  The latter allows to express general elimination rules
  1230 adequately; in this notation common elimination rules look like this:
  1231 
  1232   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1233     assumes "EX x. P x"
  1234     obtains x where "P x"
  1235 
  1236   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1237     assumes "A & B"
  1238     obtains A and B
  1239 
  1240   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1241     assumes "A | B"
  1242     obtains
  1243       A
  1244     | B
  1245 
  1246 The subsequent classical rules even refer to the formal "thesis"
  1247 explicitly:
  1248 
  1249   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1250     obtains "~ thesis"
  1251 
  1252   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1253     obtains "thesis ==> something"
  1254 
  1255 The actual proof of an 'obtains' statement is analogous to that of the
  1256 Isar proof element 'obtain', only that there may be several cases.
  1257 Optional case names may be specified in parentheses; these will be
  1258 available both in the present proof and as annotations in the
  1259 resulting rule, for later use with the 'cases' method (cf. attribute
  1260 case_names).
  1261 
  1262 * Isar: the assumptions of a long theorem statement are available as
  1263 "assms" fact in the proof context.  This is more appropriate than the
  1264 (historical) "prems", which refers to all assumptions of the current
  1265 context, including those from the target locale, proof body etc.
  1266 
  1267 * Isar: 'print_statement' prints theorems from the current theory or
  1268 proof context in long statement form, according to the syntax of a
  1269 top-level lemma.
  1270 
  1271 * Isar: 'obtain' takes an optional case name for the local context
  1272 introduction rule (default "that").
  1273 
  1274 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1275 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1276 to occur.
  1277 
  1278 * Pure: syntax "CONST name" produces a fully internalized constant
  1279 according to the current context.  This is particularly useful for
  1280 syntax translations that should refer to internal constant
  1281 representations independently of name spaces.
  1282 
  1283 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1284 instead of "FOO ". This allows multiple binder declarations to coexist
  1285 in the same context.  INCOMPATIBILITY.
  1286 
  1287 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1288 primitive that also works in a locale context (both for constants and
  1289 fixed variables). Type declaration and internal syntactic representation
  1290 of given constants retrieved from the context. Likewise, the
  1291 'no_notation' command allows to remove given syntax annotations from the
  1292 current context.
  1293 
  1294 * Isar/locales: new derived specification elements 'axiomatization',
  1295 'definition', 'abbreviation', which support type-inference, admit
  1296 object-level specifications (equality, equivalence).  See also the
  1297 isar-ref manual.  Examples:
  1298 
  1299   axiomatization
  1300     eq  (infix "===" 50) where
  1301     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1302 
  1303   definition "f x y = x + y + 1"
  1304   definition g where "g x = f x x"
  1305 
  1306   abbreviation
  1307     neq  (infix "=!=" 50) where
  1308     "x =!= y == ~ (x === y)"
  1309 
  1310 These specifications may be also used in a locale context.  Then the
  1311 constants being introduced depend on certain fixed parameters, and the
  1312 constant name is qualified by the locale base name.  An internal
  1313 abbreviation takes care for convenient input and output, making the
  1314 parameters implicit and using the original short name.  See also
  1315 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1316 entities from a monomorphic theory.
  1317 
  1318 Presently, abbreviations are only available 'in' a target locale, but
  1319 not inherited by general import expressions.  Also note that
  1320 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1321 'translations' in common applications.  The "no_abbrevs" print mode
  1322 prevents folding of abbreviations in term output.
  1323 
  1324 Concrete syntax is attached to specified constants in internal form,
  1325 independently of name spaces.  The parse tree representation is
  1326 slightly different -- use 'notation' instead of raw 'syntax', and
  1327 'translations' with explicit "CONST" markup to accommodate this.
  1328 
  1329 * Pure/Isar: unified syntax for new-style specification mechanisms
  1330 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1331 full type inference and dummy patterns ("_").  For example:
  1332 
  1333   definition "K x _ = x"
  1334 
  1335   inductive conj for A B
  1336   where "A ==> B ==> conj A B"
  1337 
  1338 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1339 the current context.  Print mode "no_abbrevs" prevents inversion of
  1340 abbreviations on output.
  1341 
  1342 * Isar/locales: improved parameter handling: use of locales "var" and
  1343 "struct" no longer necessary; - parameter renamings are no longer
  1344 required to be injective.  For example, this allows to define
  1345 endomorphisms as locale endom = homom mult mult h.
  1346 
  1347 * Isar/locales: changed the way locales with predicates are defined.
  1348 Instead of accumulating the specification, the imported expression is
  1349 now an interpretation.  INCOMPATIBILITY: different normal form of
  1350 locale expressions.  In particular, in interpretations of locales with
  1351 predicates, goals repesenting already interpreted fragments are not
  1352 removed automatically.  Use methods `intro_locales' and
  1353 `unfold_locales'; see below.
  1354 
  1355 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1356 provide backward reasoning on locales predicates.  The methods are
  1357 aware of interpretations and discharge corresponding goals.
  1358 `intro_locales' is less aggressive then `unfold_locales' and does not
  1359 unfold predicates to assumptions.
  1360 
  1361 * Isar/locales: the order in which locale fragments are accumulated
  1362 has changed.  This enables to override declarations from fragments due
  1363 to interpretations -- for example, unwanted simp rules.
  1364 
  1365 * Isar/locales: interpretation in theories and proof contexts has been
  1366 extended.  One may now specify (and prove) equations, which are
  1367 unfolded in interpreted theorems.  This is useful for replacing
  1368 defined concepts (constants depending on locale parameters) by
  1369 concepts already existing in the target context.  Example:
  1370 
  1371   interpretation partial_order ["op <= :: [int, int] => bool"]
  1372     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1373 
  1374 Typically, the constant `partial_order.less' is created by a
  1375 definition specification element in the context of locale
  1376 partial_order.
  1377 
  1378 * Method "induct": improved internal context management to support
  1379 local fixes and defines on-the-fly. Thus explicit meta-level
  1380 connectives !!  and ==> are rarely required anymore in inductive goals
  1381 (using object-logic connectives for this purpose has been long
  1382 obsolete anyway). Common proof patterns are explained in
  1383 src/HOL/Induct/Common_Patterns.thy, see also
  1384 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1385 examples.
  1386 
  1387 * Method "induct": improved handling of simultaneous goals. Instead of
  1388 introducing object-level conjunction, the statement is now split into
  1389 several conclusions, while the corresponding symbolic cases are nested
  1390 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1391 see src/HOL/Induct/Common_Patterns.thy, for example.
  1392 
  1393 * Method "induct": mutual induction rules are now specified as a list
  1394 of rule sharing the same induction cases. HOL packages usually provide
  1395 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1396 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1397 mutual induction rules differently, i.e. like this:
  1398 
  1399   (induct rule: foo_bar.inducts)
  1400   (induct set: foo bar)
  1401   (induct pred: foo bar)
  1402   (induct type: foo bar)
  1403 
  1404 The ML function ProjectRule.projections turns old-style rules into the
  1405 new format.
  1406 
  1407 * Method "coinduct": dual of induction, see
  1408 src/HOL/Library/Coinductive_List.thy for various examples.
  1409 
  1410 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1411 considered a legacy feature.
  1412 
  1413 * Attribute "symmetric" produces result with standardized schematic
  1414 variables (index 0).  Potential INCOMPATIBILITY.
  1415 
  1416 * Simplifier: by default the simplifier trace only shows top level
  1417 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1418 default. Thus there is less danger of being flooded by the trace. The
  1419 trace indicates where parts have been suppressed.
  1420   
  1421 * Provers/classical: removed obsolete classical version of elim_format
  1422 attribute; classical elim/dest rules are now treated uniformly when
  1423 manipulating the claset.
  1424 
  1425 * Provers/classical: stricter checks to ensure that supplied intro,
  1426 dest and elim rules are well-formed; dest and elim rules must have at
  1427 least one premise.
  1428 
  1429 * Provers/classical: attributes dest/elim/intro take an optional
  1430 weight argument for the rule (just as the Pure versions).  Weights are
  1431 ignored by automated tools, but determine the search order of single
  1432 rule steps.
  1433 
  1434 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1435 where the body does not mention the bound variable.  Note that dummy
  1436 patterns implicitly depend on their context of bounds, which makes
  1437 "{_. _}" match any set comprehension as expected.  Potential
  1438 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1439 constant "_idtdummy" in the binding position.
  1440 
  1441 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1442 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1443 for example "A -> B" => "Pi A (%_. B)".
  1444 
  1445 * Pure: 'class_deps' command visualizes the subclass relation, using
  1446 the graph browser tool.
  1447 
  1448 * Pure: 'print_theory' now suppresses certain internal declarations by
  1449 default; use '!' option for full details.
  1450 
  1451 
  1452 *** HOL ***
  1453 
  1454 * Method "metis" proves goals by applying the Metis general-purpose
  1455 resolution prover (see also http://gilith.com/software/metis/).
  1456 Examples are in the directory MetisExamples.  WARNING: the
  1457 Isabelle/HOL-Metis integration does not yet work properly with
  1458 multi-threading.
  1459   
  1460 * Command 'sledgehammer' invokes external automatic theorem provers as
  1461 background processes.  It generates calls to the "metis" method if
  1462 successful. These can be pasted into the proof.  Users do not have to
  1463 wait for the automatic provers to return.  WARNING: does not really
  1464 work with multi-threading.
  1465 
  1466 * New "auto_quickcheck" feature tests outermost goal statements for
  1467 potential counter-examples.  Controlled by ML references
  1468 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1469 5000 milliseconds).  Fails silently if statements is outside of
  1470 executable fragment, or any other codgenerator problem occurs.
  1471 
  1472 * New constant "undefined" with axiom "undefined x = undefined".
  1473 
  1474 * Added class "HOL.eq", allowing for code generation with polymorphic
  1475 equality.
  1476 
  1477 * Some renaming of class constants due to canonical name prefixing in
  1478 the new 'class' package:
  1479 
  1480     HOL.abs ~> HOL.abs_class.abs
  1481     HOL.divide ~> HOL.divide_class.divide
  1482     0 ~> HOL.zero_class.zero
  1483     1 ~> HOL.one_class.one
  1484     op + ~> HOL.plus_class.plus
  1485     op - ~> HOL.minus_class.minus
  1486     uminus ~> HOL.minus_class.uminus
  1487     op * ~> HOL.times_class.times
  1488     op < ~> HOL.ord_class.less
  1489     op <= > HOL.ord_class.less_eq
  1490     Nat.power ~> Power.power_class.power
  1491     Nat.size ~> Nat.size_class.size
  1492     Numeral.number_of ~> Numeral.number_class.number_of
  1493     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1494     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1495     Orderings.min ~> Orderings.ord_class.min
  1496     Orderings.max ~> Orderings.ord_class.max
  1497     Divides.op div ~> Divides.div_class.div
  1498     Divides.op mod ~> Divides.div_class.mod
  1499     Divides.op dvd ~> Divides.div_class.dvd
  1500 
  1501 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1502 
  1503 a) User-defined constants using any of the names "plus", "minus",
  1504 "times", "less" or "less_eq". The standard syntax translations for
  1505 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1506 names.
  1507 
  1508 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1509 INCOMPATIBILITY: use more specific names.
  1510 
  1511 c) Permutative equations (e.g. "a + b = b + a")
  1512 Since the change of names also changes the order of terms, permutative
  1513 rewrite rules may get applied in a different order. Experience shows
  1514 that this is rarely the case (only two adaptions in the whole Isabelle
  1515 distribution).  INCOMPATIBILITY: rewrite proofs
  1516 
  1517 d) ML code directly refering to constant names
  1518 This in general only affects hand-written proof tactics, simprocs and
  1519 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1520 Consider using @{const_name} antiquotation.
  1521 
  1522 * New class "default" with associated constant "default".
  1523 
  1524 * Function "sgn" is now overloaded and available on int, real, complex
  1525 (and other numeric types), using class "sgn".  Two possible defs of
  1526 sgn are given as equational assumptions in the classes sgn_if and
  1527 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1528 INCOMPATIBILITY.
  1529 
  1530 * Locale "partial_order" now unified with class "order" (cf. theory
  1531 Orderings), added parameter "less".  INCOMPATIBILITY.
  1532 
  1533 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1534 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1535 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1536 
  1537 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1538 changed order of proof goals in instance proofs.
  1539 
  1540 * The transitivity reasoner for partial and linear orders is set up
  1541 for classes "order" and "linorder".  Instances of the reasoner are available
  1542 in all contexts importing or interpreting the corresponding locales.
  1543 Method "order" invokes the reasoner separately; the reasoner
  1544 is also integrated with the Simplifier as a solver.  Diagnostic
  1545 command 'print_orders' shows the available instances of the reasoner
  1546 in the current context.
  1547 
  1548 * Localized monotonicity predicate in theory "Orderings"; integrated
  1549 lemmas max_of_mono and min_of_mono with this predicate.
  1550 INCOMPATIBILITY.
  1551 
  1552 * Formulation of theorem "dense" changed slightly due to integration
  1553 with new class dense_linear_order.
  1554 
  1555 * Uniform lattice theory development in HOL.
  1556 
  1557     constants "meet" and "join" now named "inf" and "sup"
  1558     constant "Meet" now named "Inf"
  1559 
  1560     classes "meet_semilorder" and "join_semilorder" now named
  1561       "lower_semilattice" and "upper_semilattice"
  1562     class "lorder" now named "lattice"
  1563     class "comp_lat" now named "complete_lattice"
  1564 
  1565     Instantiation of lattice classes allows explicit definitions
  1566     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1567 
  1568   INCOMPATIBILITY.  Theorem renames:
  1569 
  1570     meet_left_le            ~> inf_le1
  1571     meet_right_le           ~> inf_le2
  1572     join_left_le            ~> sup_ge1
  1573     join_right_le           ~> sup_ge2
  1574     meet_join_le            ~> inf_sup_ord
  1575     le_meetI                ~> le_infI
  1576     join_leI                ~> le_supI
  1577     le_meet                 ~> le_inf_iff
  1578     le_join                 ~> ge_sup_conv
  1579     meet_idempotent         ~> inf_idem
  1580     join_idempotent         ~> sup_idem
  1581     meet_comm               ~> inf_commute
  1582     join_comm               ~> sup_commute
  1583     meet_leI1               ~> le_infI1
  1584     meet_leI2               ~> le_infI2
  1585     le_joinI1               ~> le_supI1
  1586     le_joinI2               ~> le_supI2
  1587     meet_assoc              ~> inf_assoc
  1588     join_assoc              ~> sup_assoc
  1589     meet_left_comm          ~> inf_left_commute
  1590     meet_left_idempotent    ~> inf_left_idem
  1591     join_left_comm          ~> sup_left_commute
  1592     join_left_idempotent    ~> sup_left_idem
  1593     meet_aci                ~> inf_aci
  1594     join_aci                ~> sup_aci
  1595     le_def_meet             ~> le_iff_inf
  1596     le_def_join             ~> le_iff_sup
  1597     join_absorp2            ~> sup_absorb2
  1598     join_absorp1            ~> sup_absorb1
  1599     meet_absorp1            ~> inf_absorb1
  1600     meet_absorp2            ~> inf_absorb2
  1601     meet_join_absorp        ~> inf_sup_absorb
  1602     join_meet_absorp        ~> sup_inf_absorb
  1603     distrib_join_le         ~> distrib_sup_le
  1604     distrib_meet_le         ~> distrib_inf_le
  1605 
  1606     add_meet_distrib_left   ~> add_inf_distrib_left
  1607     add_join_distrib_left   ~> add_sup_distrib_left
  1608     is_join_neg_meet        ~> is_join_neg_inf
  1609     is_meet_neg_join        ~> is_meet_neg_sup
  1610     add_meet_distrib_right  ~> add_inf_distrib_right
  1611     add_join_distrib_right  ~> add_sup_distrib_right
  1612     add_meet_join_distribs  ~> add_sup_inf_distribs
  1613     join_eq_neg_meet        ~> sup_eq_neg_inf
  1614     meet_eq_neg_join        ~> inf_eq_neg_sup
  1615     add_eq_meet_join        ~> add_eq_inf_sup
  1616     meet_0_imp_0            ~> inf_0_imp_0
  1617     join_0_imp_0            ~> sup_0_imp_0
  1618     meet_0_eq_0             ~> inf_0_eq_0
  1619     join_0_eq_0             ~> sup_0_eq_0
  1620     neg_meet_eq_join        ~> neg_inf_eq_sup
  1621     neg_join_eq_meet        ~> neg_sup_eq_inf
  1622     join_eq_if              ~> sup_eq_if
  1623 
  1624     mono_meet               ~> mono_inf
  1625     mono_join               ~> mono_sup
  1626     meet_bool_eq            ~> inf_bool_eq
  1627     join_bool_eq            ~> sup_bool_eq
  1628     meet_fun_eq             ~> inf_fun_eq
  1629     join_fun_eq             ~> sup_fun_eq
  1630     meet_set_eq             ~> inf_set_eq
  1631     join_set_eq             ~> sup_set_eq
  1632     meet1_iff               ~> inf1_iff
  1633     meet2_iff               ~> inf2_iff
  1634     meet1I                  ~> inf1I
  1635     meet2I                  ~> inf2I
  1636     meet1D1                 ~> inf1D1
  1637     meet2D1                 ~> inf2D1
  1638     meet1D2                 ~> inf1D2
  1639     meet2D2                 ~> inf2D2
  1640     meet1E                  ~> inf1E
  1641     meet2E                  ~> inf2E
  1642     join1_iff               ~> sup1_iff
  1643     join2_iff               ~> sup2_iff
  1644     join1I1                 ~> sup1I1
  1645     join2I1                 ~> sup2I1
  1646     join1I1                 ~> sup1I1
  1647     join2I2                 ~> sup1I2
  1648     join1CI                 ~> sup1CI
  1649     join2CI                 ~> sup2CI
  1650     join1E                  ~> sup1E
  1651     join2E                  ~> sup2E
  1652 
  1653     is_meet_Meet            ~> is_meet_Inf
  1654     Meet_bool_def           ~> Inf_bool_def
  1655     Meet_fun_def            ~> Inf_fun_def
  1656     Meet_greatest           ~> Inf_greatest
  1657     Meet_lower              ~> Inf_lower
  1658     Meet_set_def            ~> Inf_set_def
  1659 
  1660     Sup_def                 ~> Sup_Inf
  1661     Sup_bool_eq             ~> Sup_bool_def
  1662     Sup_fun_eq              ~> Sup_fun_def
  1663     Sup_set_eq              ~> Sup_set_def
  1664 
  1665     listsp_meetI            ~> listsp_infI
  1666     listsp_meet_eq          ~> listsp_inf_eq
  1667 
  1668     meet_min                ~> inf_min
  1669     join_max                ~> sup_max
  1670 
  1671 * Added syntactic class "size"; overloaded constant "size" now has
  1672 type "'a::size ==> bool"
  1673 
  1674 * Internal reorganisation of `size' of datatypes: size theorems
  1675 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1676 simplification rules by default!); theorems "prod.size" now named
  1677 "*.size".
  1678 
  1679 * Class "div" now inherits from class "times" rather than "type".
  1680 INCOMPATIBILITY.
  1681 
  1682 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1683 Linorder etc.  have disappeared; operations defined in terms of
  1684 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1685 
  1686 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1687 
  1688 * HOL-Word: New extensive library and type for generic, fixed size
  1689 machine words, with arithemtic, bit-wise, shifting and rotating
  1690 operations, reflection into int, nat, and bool lists, automation for
  1691 linear arithmetic (by automatic reflection into nat or int), including
  1692 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1693 arithmetic type classes, supporting automatic simplification of
  1694 numerals on all operations.
  1695 
  1696 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1697 
  1698 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1699 
  1700 * Code generator library theories:
  1701   - Code_Integer represents HOL integers by big integer literals in target
  1702     languages.
  1703   - Code_Char represents HOL characters by character literals in target
  1704     languages.
  1705   - Code_Char_chr like Code_Char, but also offers treatment of character
  1706     codes; includes Code_Integer.
  1707   - Executable_Set allows to generate code for finite sets using lists.
  1708   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1709     denominator).
  1710   - Executable_Real implements a subset of real numbers, namly those
  1711     representable by rational numbers.
  1712   - Efficient_Nat implements natural numbers by integers, which in general will
  1713     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1714     includes Code_Integer.
  1715   - Code_Index provides an additional datatype index which is mapped to
  1716     target-language built-in integers.
  1717   - Code_Message provides an additional datatype message_string which is isomorphic to
  1718     strings; messages are mapped to target-language strings.
  1719 
  1720 * New package for inductive predicates
  1721 
  1722   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1723 
  1724     inductive
  1725       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1726       for z_1 :: U_1 and ... and z_n :: U_m
  1727     where
  1728       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1729     | ...
  1730 
  1731   with full support for type-inference, rather than
  1732 
  1733     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1734 
  1735     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1736     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1737 
  1738     inductive "s z_1 ... z_m"
  1739     intros
  1740       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1741       ...
  1742 
  1743   For backward compatibility, there is a wrapper allowing inductive
  1744   sets to be defined with the new package via
  1745 
  1746     inductive_set
  1747       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1748       for z_1 :: U_1 and ... and z_n :: U_m
  1749     where
  1750       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1751     | ...
  1752 
  1753   or
  1754 
  1755     inductive_set
  1756       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1757       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1758       for z_1 :: U_1 and ... and z_n :: U_m
  1759     where
  1760       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1761     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1762     | ...
  1763 
  1764   if the additional syntax "p ..." is required.
  1765 
  1766   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1767   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1768 
  1769   INCOMPATIBILITIES:
  1770 
  1771   - Since declaration and definition of inductive sets or predicates
  1772     is no longer separated, abbreviations involving the newly
  1773     introduced sets or predicates must be specified together with the
  1774     introduction rules after the 'where' keyword (see above), rather
  1775     than before the actual inductive definition.
  1776 
  1777   - The variables in induction and elimination rules are now
  1778     quantified in the order of their occurrence in the introduction
  1779     rules, rather than in alphabetical order. Since this may break
  1780     some proofs, these proofs either have to be repaired, e.g. by
  1781     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1782     statements of the form
  1783 
  1784       case (rule_i a_i_1 ... a_i_{k_i})
  1785 
  1786     or the old order of quantification has to be restored by explicitly adding
  1787     meta-level quantifiers in the introduction rules, i.e.
  1788 
  1789       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1790 
  1791   - The format of the elimination rules is now
  1792 
  1793       p z_1 ... z_m x_1 ... x_n ==>
  1794         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1795         ==> ... ==> P
  1796 
  1797     for predicates and
  1798 
  1799       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1800         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1801         ==> ... ==> P
  1802 
  1803     for sets rather than
  1804 
  1805       x : s z_1 ... z_m ==>
  1806         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1807         ==> ... ==> P
  1808 
  1809     This may require terms in goals to be expanded to n-tuples
  1810     (e.g. using case_tac or simplification with the split_paired_all
  1811     rule) before the above elimination rule is applicable.
  1812 
  1813   - The elimination or case analysis rules for (mutually) inductive
  1814     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1815     list of rules "p_1_..._p_k.elims" is no longer available.
  1816 
  1817 * New package "function"/"fun" for general recursive functions,
  1818 supporting mutual and nested recursion, definitions in local contexts,
  1819 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1820 for small examples, and the separate tutorial on the function
  1821 package. The old recdef "package" is still available as before, but
  1822 users are encouraged to use the new package.
  1823 
  1824 * Method "lexicographic_order" automatically synthesizes termination
  1825 relations as lexicographic combinations of size measures. 
  1826 
  1827 * Case-expressions allow arbitrary constructor-patterns (including
  1828 "_") and take their order into account, like in functional
  1829 programming.  Internally, this is translated into nested
  1830 case-expressions; missing cases are added and mapped to the predefined
  1831 constant "undefined". In complicated cases printing may no longer show
  1832 the original input but the internal form. Lambda-abstractions allow
  1833 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1834 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1835 variable.
  1836 
  1837 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1838 is an abbreviation for "of_nat :: nat => int". The simplification
  1839 rules for "of_nat" have been changed to work like "int" did
  1840 previously.  Potential INCOMPATIBILITY:
  1841   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1842   - of_nat_diff and of_nat_mult are no longer default simp rules
  1843 
  1844 * Method "algebra" solves polynomial equations over (semi)rings using
  1845 Groebner bases. The (semi)ring structure is defined by locales and the
  1846 tool setup depends on that generic context. Installing the method for
  1847 a specific type involves instantiating the locale and possibly adding
  1848 declarations for computation on the coefficients.  The method is
  1849 already instantiated for natural numbers and for the axiomatic class
  1850 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1851 CALCULEMUS 2007 for the general principles underlying this
  1852 architecture of context-aware proof-tools.
  1853 
  1854 * Method "ferrack" implements quantifier elimination over
  1855 special-purpose dense linear orders using locales (analogous to
  1856 "algebra"). The method is already installed for class
  1857 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1858 rat, etc.
  1859 
  1860 * Former constant "List.op @" now named "List.append".  Use ML
  1861 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1862 circumvent possible incompatibilities when working on ML level.
  1863 
  1864 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1865 
  1866 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1867 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1868 
  1869 * New syntax for Haskell-like list comprehension (input only), eg.
  1870 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1871 
  1872 * The special syntax for function "filter" has changed from [x :
  1873 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1874 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1875 
  1876 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1877 defined on nat only, as an abbreviation for [a..<Suc b]
  1878 INCOMPATIBILITY.
  1879 
  1880 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1881 
  1882 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1883 
  1884 * New lemma collection field_simps (an extension of ring_simps) for
  1885 manipulating (in)equations involving division. Multiplies with all
  1886 denominators that can be proved to be non-zero (in equations) or
  1887 positive/negative (in inequations).
  1888 
  1889 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1890 have been improved and renamed to ring_simps, group_simps and
  1891 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1892 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1893 
  1894 * Theory Library/Commutative_Ring: switched from recdef to function
  1895 package; constants add, mul, pow now curried.  Infix syntax for
  1896 algebraic operations.
  1897 
  1898 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1899 INCOMPATIBILITY.
  1900 
  1901 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1902 INCOMPATIBILITY.
  1903 
  1904 * HOL/records: generalised field-update to take a function on the
  1905 field rather than the new value: r(|A := x|) is translated to A_update
  1906 (K x) r The K-combinator that is internally used is called K_record.
  1907 INCOMPATIBILITY: Usage of the plain update functions has to be
  1908 adapted.
  1909  
  1910 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1911 * x = 0, which are required for a semiring.  Richer structures do not
  1912 inherit from semiring_0 anymore, because this property is a theorem
  1913 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1914 there is more to prove, but this is mostly trivial.
  1915 
  1916 * Class "recpower" is generalized to arbitrary monoids, not just
  1917 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1918 commutativity or semiring properties additionally.
  1919 
  1920 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1921 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1922 better use 'abbreviation'.
  1923 
  1924 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1925 
  1926 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1927 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1928 significant changes for setting up numeral syntax for types:
  1929   - New constants Numeral.pred and Numeral.succ instead
  1930       of former Numeral.bin_pred and Numeral.bin_succ.
  1931   - Use integer operations instead of bin_add, bin_mult and so on.
  1932   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1933   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1934 
  1935 See src/HOL/Integ/IntArith.thy for an example setup.
  1936 
  1937 * Command 'normal_form' computes the normal form of a term that may
  1938 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1939 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1940 heavy-duty computations because the functions are compiled to ML
  1941 first.  Correspondingly, a method "normalization" is provided.  See
  1942 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1943 
  1944 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1945 25 like -->); output depends on the "iff" print_mode, the default is
  1946 "A = B" (with priority 50).
  1947 
  1948 * Relations less (<) and less_eq (<=) are also available on type bool.
  1949 Modified syntax to disallow nesting without explicit parentheses,
  1950 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1951 INCOMPATIBILITY.
  1952 
  1953 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1954 
  1955 * Relation composition operator "op O" now has precedence 75 and binds
  1956 stronger than union and intersection. INCOMPATIBILITY.
  1957 
  1958 * The old set interval syntax "{m..n(}" (and relatives) has been
  1959 removed.  Use "{m..<n}" (and relatives) instead.
  1960 
  1961 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1962 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1963 ``declare [[simproc del: neq]]''.
  1964 
  1965 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1966 True/False.
  1967 
  1968 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1969 
  1970 * Theorem setsum_mult renamed to setsum_right_distrib.
  1971 
  1972 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1973 ``rule'' method.
  1974 
  1975 * Reimplemented methods "sat" and "satx", with several improvements:
  1976 goals no longer need to be stated as "<prems> ==> False", equivalences
  1977 (i.e. "=" on type bool) are handled, variable names of the form
  1978 "lit_<n>" are no longer reserved, significant speedup.
  1979 
  1980 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1981 zChaff is still supported as well.
  1982 
  1983 * 'inductive' and 'datatype': provide projections of mutual rules,
  1984 bundled as foo_bar.inducts;
  1985 
  1986 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1987 Library.
  1988 
  1989 * Library: moved theory Accessible_Part to main HOL.
  1990 
  1991 * Library: added theory Coinductive_List of potentially infinite lists
  1992 as greatest fixed-point.
  1993 
  1994 * Library: added theory AssocList which implements (finite) maps as
  1995 association lists.
  1996 
  1997 * Method "evaluation" solves goals (i.e. a boolean expression)
  1998 efficiently by compiling it to ML.  The goal is "proved" (via an
  1999 oracle) if it evaluates to True.
  2000 
  2001 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2002 also when invoked by the simplifier.  This results in the Simplifier
  2003 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2004 Configuration option fast_arith_split_limit=0 recovers the old
  2005 behavior.
  2006 
  2007 * Support for hex (0x20) and binary (0b1001) numerals.
  2008 
  2009 * New method: reify eqs (t), where eqs are equations for an
  2010 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2011 parameter, computes a term s::'b and a list xs::'a list and proves the
  2012 theorem I xs s = t. This is also known as reification or quoting. The
  2013 resulting theorem is applied to the subgoal to substitute t with I xs
  2014 s.  If t is omitted, the subgoal itself is reified.
  2015 
  2016 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2017 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2018 where f is supposed to be a computable function (in the sense of code
  2019 generattion). The method uses reify to compute s and xs as above then
  2020 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2021 r and finally gets the theorem t = r, which is again applied to the
  2022 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2023 
  2024 * Reflection: Automatic reification now handels binding, an example is
  2025 available in src/HOL/ex/ReflectionEx.thy
  2026 
  2027 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2028 command 'statespace' that is similar to 'record', but introduces an
  2029 abstract specification based on the locale infrastructure instead of
  2030 HOL types.  This leads to extra flexibility in composing state spaces,
  2031 in particular multiple inheritance and renaming of components.
  2032 
  2033 
  2034 *** HOL-Complex ***
  2035 
  2036 * Hyperreal: Functions root and sqrt are now defined on negative real
  2037 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2038 Nonnegativity side conditions have been removed from many lemmas, so
  2039 that more subgoals may now be solved by simplification; potential
  2040 INCOMPATIBILITY.
  2041 
  2042 * Real: new type classes formalize real normed vector spaces and
  2043 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2044 and norm :: 'a => real.
  2045 
  2046 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2047 reals into other types. The overloaded constant Reals :: 'a set is now
  2048 defined as range of_real; potential INCOMPATIBILITY.
  2049 
  2050 * Real: proper support for ML code generation, including 'quickcheck'.
  2051 Reals are implemented as arbitrary precision rationals.
  2052 
  2053 * Hyperreal: Several constants that previously worked only for the
  2054 reals have been generalized, so they now work over arbitrary vector
  2055 spaces. Type annotations may need to be added in some cases; potential
  2056 INCOMPATIBILITY.
  2057 
  2058   Infinitesimal  :: ('a::real_normed_vector) star set
  2059   HFinite        :: ('a::real_normed_vector) star set
  2060   HInfinite      :: ('a::real_normed_vector) star set
  2061   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2062   monad          :: ('a::real_normed_vector) star => 'a star set
  2063   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2064   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2065   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2066   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2067   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2068   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2069   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2070   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2071   sgn            :: 'a::real_normed_vector => 'a
  2072   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2073 
  2074 * Complex: Some complex-specific constants are now abbreviations for
  2075 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2076 hnorm.  Other constants have been entirely removed in favor of the
  2077 polymorphic versions (INCOMPATIBILITY):
  2078 
  2079   approx        <-- capprox
  2080   HFinite       <-- CFinite
  2081   HInfinite     <-- CInfinite
  2082   Infinitesimal <-- CInfinitesimal
  2083   monad         <-- cmonad
  2084   galaxy        <-- cgalaxy
  2085   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2086   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2087   (ns)deriv     <-- (ns)cderiv
  2088 
  2089 
  2090 *** HOL-Algebra ***
  2091 
  2092 * Formalisation of ideals and the quotient construction over rings.
  2093 
  2094 * Order and lattice theory no longer based on records.
  2095 INCOMPATIBILITY.
  2096 
  2097 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2098 greatest_closed.  INCOMPATIBILITY.
  2099 
  2100 * Method algebra is now set up via an attribute.  For examples see
  2101 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2102 of algebraic structures.
  2103 
  2104 * Renamed theory CRing to Ring.
  2105 
  2106 
  2107 *** HOL-Nominal ***
  2108 
  2109 * Substantial, yet incomplete support for nominal datatypes (binding
  2110 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2111 src/HOL/Nominal/Examples.  Prospective users should consult
  2112 http://isabelle.in.tum.de/nominal/
  2113 
  2114 
  2115 *** ML ***
  2116 
  2117 * ML basics: just one true type int, which coincides with IntInf.int
  2118 (even on SML/NJ).
  2119 
  2120 * ML within Isar: antiquotations allow to embed statically-checked
  2121 formal entities in the source, referring to the context available at
  2122 compile-time.  For example:
  2123 
  2124 ML {* @{sort "{zero,one}"} *}
  2125 ML {* @{typ "'a => 'b"} *}
  2126 ML {* @{term "%x. x"} *}
  2127 ML {* @{prop "x == y"} *}
  2128 ML {* @{ctyp "'a => 'b"} *}
  2129 ML {* @{cterm "%x. x"} *}
  2130 ML {* @{cprop "x == y"} *}
  2131 ML {* @{thm asm_rl} *}
  2132 ML {* @{thms asm_rl} *}
  2133 ML {* @{type_name c} *}
  2134 ML {* @{type_syntax c} *}
  2135 ML {* @{const_name c} *}
  2136 ML {* @{const_syntax c} *}
  2137 ML {* @{context} *}
  2138 ML {* @{theory} *}
  2139 ML {* @{theory Pure} *}
  2140 ML {* @{theory_ref} *}
  2141 ML {* @{theory_ref Pure} *}
  2142 ML {* @{simpset} *}
  2143 ML {* @{claset} *}
  2144 ML {* @{clasimpset} *}
  2145 
  2146 The same works for sources being ``used'' within an Isar context.
  2147 
  2148 * ML in Isar: improved error reporting; extra verbosity with
  2149 ML_Context.trace enabled.
  2150 
  2151 * Pure/General/table.ML: the join operations now works via exceptions
  2152 DUP/SAME instead of type option. This is simpler in simple cases, and
  2153 admits slightly more efficient complex applications.
  2154 
  2155 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2156 use Context.generic instead of just theory.
  2157 
  2158 * Pure: datatype Context.generic joins theory/Proof.context and
  2159 provides some facilities for code that works in either kind of
  2160 context, notably GenericDataFun for uniform theory and proof data.
  2161 
  2162 * Pure: simplified internal attribute type, which is now always
  2163 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2164 local (Proof.context) attributes have been discontinued, while
  2165 minimizing code duplication. Thm.rule_attribute and
  2166 Thm.declaration_attribute build canonical attributes; see also structure
  2167 Context for further operations on Context.generic, notably
  2168 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2169 declarations and definitions.
  2170 
  2171 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2172 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2173 init only required for impure data. INCOMPATIBILITY: empty really need
  2174 to be empty (no dependencies on theory content!)
  2175 
  2176 * Pure/kernel: consts certification ignores sort constraints given in
  2177 signature declarations. (This information is not relevant to the
  2178 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2179 potential INCOMPATIBILITY.
  2180 
  2181 * Pure: axiomatic type classes are now purely definitional, with
  2182 explicit proofs of class axioms and super class relations performed
  2183 internally. See Pure/axclass.ML for the main internal interfaces --
  2184 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2185 AxClass.axiomatize_class/classrel/arity supersede
  2186 Sign.add_classes/classrel/arities.
  2187 
  2188 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2189 global/local versions on theory vs. Proof.context have been
  2190 discontinued; Attrib.syntax and Method.syntax have been adapted
  2191 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2192 attributes, methods, etc.
  2193 
  2194 * Pure: several functions of signature "... -> theory -> theory * ..."
  2195 have been reoriented to "... -> theory -> ... * theory" in order to
  2196 allow natural usage in combination with the ||>, ||>>, |-> and
  2197 fold_map combinators.
  2198 
  2199 * Pure: official theorem names (closed derivations) and additional
  2200 comments (tags) are now strictly separate.  Name hints -- which are
  2201 maintained as tags -- may be attached any time without affecting the
  2202 derivation.
  2203 
  2204 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2205 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2206 achieve the old behaviour.
  2207 
  2208 * Pure: the "Goal" constant is now called "prop", supporting a
  2209 slightly more general idea of ``protecting'' meta-level rule
  2210 statements.
  2211 
  2212 * Pure: Logic.(un)varify only works in a global context, which is now
  2213 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2214 Logic.legacy_(un)varify as temporary workaround.
  2215 
  2216 * Pure: structure Name provides scalable operations for generating
  2217 internal variable names, notably Name.variants etc.  This replaces
  2218 some popular functions from term.ML:
  2219 
  2220   Term.variant		->  Name.variant
  2221   Term.variantlist	->  Name.variant_list
  2222   Term.invent_names	->  Name.invent_list
  2223 
  2224 Note that low-level renaming rarely occurs in new code -- operations
  2225 from structure Variable are used instead (see below).
  2226 
  2227 * Pure: structure Variable provides fundamental operations for proper
  2228 treatment of fixed/schematic variables in a context.  For example,
  2229 Variable.import introduces fixes for schematics of given facts and
  2230 Variable.export reverses the effect (up to renaming) -- this replaces
  2231 various freeze_thaw operations.
  2232 
  2233 * Pure: structure Goal provides simple interfaces for
  2234 init/conclude/finish and tactical prove operations (replacing former
  2235 Tactic.prove).  Goal.prove is the canonical way to prove results
  2236 within a given context; Goal.prove_global is a degraded version for
  2237 theory level goals, including a global Drule.standard.  Note that
  2238 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2239 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2240 in a locale context).
  2241 
  2242 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2243 and type checking (Syntax.check_term etc.), with common combinations
  2244 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2245 which are considered legacy and await removal.
  2246 
  2247 * Pure/Syntax: generic interfaces for type unchecking
  2248 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2249 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2250 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2251 available for convenience, but refer to the very same operations using
  2252 a mere theory instead of a full context.
  2253 
  2254 * Isar: simplified treatment of user-level errors, using exception
  2255 ERROR of string uniformly.  Function error now merely raises ERROR,
  2256 without any side effect on output channels.  The Isar toplevel takes
  2257 care of proper display of ERROR exceptions.  ML code may use plain
  2258 handle/can/try; cat_error may be used to concatenate errors like this:
  2259 
  2260   ... handle ERROR msg => cat_error msg "..."
  2261 
  2262 Toplevel ML code (run directly or through the Isar toplevel) may be
  2263 embedded into the Isar toplevel with exception display/debug like
  2264 this:
  2265 
  2266   Isar.toplevel (fn () => ...)
  2267 
  2268 INCOMPATIBILITY, removed special transform_error facilities, removed
  2269 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2270 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2271 -- use plain ERROR instead.
  2272 
  2273 * Isar: theory setup now has type (theory -> theory), instead of a
  2274 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2275 
  2276 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2277 ProofContext.debug/verbose flags.
  2278 
  2279 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2280 theory before entering a proof state.  Transactions now always see a
  2281 quasi-functional intermediate checkpoint, both in interactive and
  2282 batch mode.
  2283 
  2284 * Isar: simplified interfaces for outer syntax.  Renamed
  2285 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2286 OuterSyntax.add_parsers -- this functionality is now included in
  2287 OuterSyntax.command etc.  INCOMPATIBILITY.
  2288 
  2289 * Simplifier: the simpset of a running simplification process now
  2290 contains a proof context (cf. Simplifier.the_context), which is the
  2291 very context that the initial simpset has been retrieved from (by
  2292 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2293 (solver, looper etc.) may depend on arbitrary proof data.
  2294 
  2295 * Simplifier.inherit_context inherits the proof context (plus the
  2296 local bounds) of the current simplification process; any simproc
  2297 etc. that calls the Simplifier recursively should do this!  Removed
  2298 former Simplifier.inherit_bounds, which is already included here --
  2299 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2300 specify an explicit context using Simplifier.context/theory_context.
  2301 
  2302 * Simplifier/Classical Reasoner: more abstract interfaces
  2303 change_simpset/claset for modifying the simpset/claset reference of a
  2304 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2305 INCOMPATIBILITY.
  2306 
  2307 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2308 "Trueprop" etc.
  2309 
  2310 
  2311 *** System ***
  2312 
  2313 * settings: the default heap location within ISABELLE_HOME_USER now
  2314 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2315 Isabelle installations.
  2316 
  2317 * isabelle-process: option -S (secure mode) disables some critical
  2318 operations, notably runtime compilation and evaluation of ML source
  2319 code.
  2320 
  2321 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2322 
  2323 * Support for parallel execution, using native multicore support of
  2324 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2325 independent theories, according to the given theory header
  2326 specifications. The maximum number of worker threads is specified via
  2327 usedir option -M or the "max-threads" setting in Proof General. A
  2328 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2329 to 6 on a 8-core machine.  User-code needs to observe certain
  2330 guidelines for thread-safe programming, see appendix A in the Isar
  2331 Implementation manual.
  2332 
  2333 
  2334 
  2335 New in Isabelle2005 (October 2005)
  2336 ----------------------------------
  2337 
  2338 *** General ***
  2339 
  2340 * Theory headers: the new header syntax for Isar theories is
  2341 
  2342   theory <name>
  2343   imports <theory1> ... <theoryN>
  2344   uses <file1> ... <fileM>
  2345   begin
  2346 
  2347 where the 'uses' part is optional.  The previous syntax
  2348 
  2349   theory <name> = <theory1> + ... + <theoryN>:
  2350 
  2351 will disappear in the next release.  Use isatool fixheaders to convert
  2352 existing theory files.  Note that there is no change in ancient
  2353 non-Isar theories now, but these will disappear soon.
  2354 
  2355 * Theory loader: parent theories can now also be referred to via
  2356 relative and absolute paths.
  2357 
  2358 * Command 'find_theorems' searches for a list of criteria instead of a
  2359 list of constants. Known criteria are: intro, elim, dest, name:string,
  2360 simp:term, and any term. Criteria can be preceded by '-' to select
  2361 theorems that do not match. Intro, elim, dest select theorems that
  2362 match the current goal, name:s selects theorems whose fully qualified
  2363 name contain s, and simp:term selects all simplification rules whose
  2364 lhs match term.  Any other term is interpreted as pattern and selects
  2365 all theorems matching the pattern. Available in ProofGeneral under
  2366 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2367 
  2368   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2369 
  2370 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2371 matching the current goal as introduction rule and not having "HOL."
  2372 in their name (i.e. not being defined in theory HOL).
  2373 
  2374 * Command 'thms_containing' has been discontinued in favour of
  2375 'find_theorems'; INCOMPATIBILITY.
  2376 
  2377 * Communication with Proof General is now 8bit clean, which means that
  2378 Unicode text in UTF-8 encoding may be used within theory texts (both
  2379 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2380 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2381 
  2382   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2383   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2384 
  2385 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2386 Classical Reasoner.  Typical big applications run around 2 times
  2387 faster.
  2388 
  2389 
  2390 *** Document preparation ***
  2391 
  2392 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2393 of raw sources.  Only those symbols that do not require additional
  2394 LaTeX packages (depending on comments in isabellesym.sty) are
  2395 displayed properly, everything else is left verbatim.  isatool display
  2396 and isatool print are used as front ends (these are subject to the
  2397 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2398 
  2399 * Command tags control specific markup of certain regions of text,
  2400 notably folding and hiding.  Predefined tags include "theory" (for
  2401 theory begin and end), "proof" for proof commands, and "ML" for
  2402 commands involving ML code; the additional tags "visible" and
  2403 "invisible" are unused by default.  Users may give explicit tag
  2404 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2405 interpretation of tags is determined by the LaTeX job during document
  2406 preparation: see option -V of isatool usedir, or options -n and -t of
  2407 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2408 \isadroptag.
  2409 
  2410 Several document versions may be produced at the same time via isatool
  2411 usedir (the generated index.html will link all of them).  Typical
  2412 specifications include ''-V document=theory,proof,ML'' to present
  2413 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2414 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2415 these parts without any formal replacement text.  The Isabelle site
  2416 default settings produce ''document'' and ''outline'' versions as
  2417 specified above.
  2418 
  2419 * Several new antiquotations:
  2420 
  2421   @{term_type term} prints a term with its type annotated;
  2422 
  2423   @{typeof term} prints the type of a term;
  2424 
  2425   @{const const} is the same as @{term const}, but checks that the
  2426   argument is a known logical constant;
  2427 
  2428   @{term_style style term} and @{thm_style style thm} print a term or
  2429   theorem applying a "style" to it
  2430 
  2431   @{ML text}
  2432 
  2433 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2434 definitions, equations, inequations etc., 'concl' printing only the
  2435 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2436 to print the specified premise.  TermStyle.add_style provides an ML
  2437 interface for introducing further styles.  See also the "LaTeX Sugar"
  2438 document practical applications.  The ML antiquotation prints
  2439 type-checked ML expressions verbatim.
  2440 
  2441 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2442 and 'text' support optional locale specification '(in loc)', which
  2443 specifies the default context for interpreting antiquotations.  For
  2444 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2445 
  2446 * Option 'locale=NAME' of antiquotations specifies an alternative
  2447 context interpreting the subsequent argument.  For example: @{thm
  2448 [locale=lattice] inf_assoc}.
  2449 
  2450 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2451 a proof context.
  2452 
  2453 * Proper output of antiquotations for theory commands involving a
  2454 proof context (such as 'locale' or 'theorem (in loc) ...').
  2455 
  2456 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2457 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2458 
  2459 * isatool usedir: new option -C (default true) controls whether option
  2460 -D should include a copy of the original document directory; -C false
  2461 prevents unwanted effects such as copying of administrative CVS data.
  2462 
  2463 
  2464 *** Pure ***
  2465 
  2466 * Considerably improved version of 'constdefs' command.  Now performs
  2467 automatic type-inference of declared constants; additional support for
  2468 local structure declarations (cf. locales and HOL records), see also
  2469 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2470 sequential dependencies of definitions within a single 'constdefs'
  2471 section; moreover, the declared name needs to be an identifier.  If
  2472 all fails, consider to fall back on 'consts' and 'defs' separately.
  2473 
  2474 * Improved indexed syntax and implicit structures.  First of all,
  2475 indexed syntax provides a notational device for subscripted
  2476 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2477 expressions.  Secondly, in a local context with structure
  2478 declarations, number indexes \<^sub>n or the empty index (default
  2479 number 1) refer to a certain fixed variable implicitly; option
  2480 show_structs controls printing of implicit structures.  Typical
  2481 applications of these concepts involve record types and locales.
  2482 
  2483 * New command 'no_syntax' removes grammar declarations (and
  2484 translations) resulting from the given syntax specification, which is
  2485 interpreted in the same manner as for the 'syntax' command.
  2486 
  2487 * 'Advanced' translation functions (parse_translation etc.) may depend
  2488 on the signature of the theory context being presently used for
  2489 parsing/printing, see also isar-ref manual.
  2490 
  2491 * Improved 'oracle' command provides a type-safe interface to turn an
  2492 ML expression of type theory -> T -> term into a primitive rule of
  2493 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2494 is already included here); see also FOL/ex/IffExample.thy;
  2495 INCOMPATIBILITY.
  2496 
  2497 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2498 before); "cI" is no longer bound, use "c.intro" instead.
  2499 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2500 axclasses vs. locales.
  2501 
  2502 * Improved internal renaming of symbolic identifiers -- attach primes
  2503 instead of base 26 numbers.
  2504 
  2505 * New flag show_question_marks controls printing of leading question
  2506 marks in schematic variable names.
  2507 
  2508 * In schematic variable names, *any* symbol following \<^isub> or
  2509 \<^isup> is now treated as part of the base name.  For example, the
  2510 following works without printing of awkward ".0" indexes:
  2511 
  2512   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2513     by simp
  2514 
  2515 * Inner syntax includes (*(*nested*) comments*).
  2516 
  2517 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2518 annotations as "(00...)".
  2519 
  2520 * Clear separation of logical types and nonterminals, where the latter
  2521 may only occur in 'syntax' specifications or type abbreviations.
  2522 Before that distinction was only partially implemented via type class
  2523 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2524 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2525 exotic syntax specifications may require further adaption
  2526 (e.g. Cube/Cube.thy).
  2527 
  2528 * Removed obsolete type class "logic", use the top sort {} instead.
  2529 Note that non-logical types should be declared as 'nonterminals'
  2530 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2531 specifications.
  2532 
  2533 * Attributes 'induct' and 'cases': type or set names may now be
  2534 locally fixed variables as well.
  2535 
  2536 * Simplifier: can now control the depth to which conditional rewriting
  2537 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2538 Limit.
  2539 
  2540 * Simplifier: simplification procedures may now take the current
  2541 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2542 interface), which is very useful for calling the Simplifier
  2543 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2544 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2545 low-level mk_simproc no longer applies Logic.varify internally, to
  2546 allow for use in a context of fixed variables.
  2547 
  2548 * thin_tac now works even if the assumption being deleted contains !!
  2549 or ==>.  More generally, erule now works even if the major premise of
  2550 the elimination rule contains !! or ==>.
  2551 
  2552 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2553 
  2554 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2555 from Pure, which contains all common declarations already.  Both
  2556 theories are defined via plain Isabelle/Isar .thy files.
  2557 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2558 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2559 use isatool fixcpure to adapt your theory and ML sources.
  2560 
  2561 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2562 selections of theorems in named facts via index ranges.
  2563 
  2564 * 'print_theorems': in theory mode, really print the difference
  2565 wrt. the last state (works for interactive theory development only),
  2566 in proof mode print all local facts (cf. 'print_facts');
  2567 
  2568 * 'hide': option '(open)' hides only base names.
  2569 
  2570 * More efficient treatment of intermediate checkpoints in interactive
  2571 theory development.
  2572 
  2573 * Code generator is now invoked via code_module (incremental code
  2574 generation) and code_library (modular code generation, ML structures
  2575 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2576 must be quoted when used as identifiers.
  2577 
  2578 * New 'value' command for reading, evaluating and printing terms using
  2579 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2580 quoted when used as identifier.
  2581 
  2582 
  2583 *** Locales ***
  2584 
  2585 * New commands for the interpretation of locale expressions in
  2586 theories (1), locales (2) and proof contexts (3).  These generate
  2587 proof obligations from the expression specification.  After the
  2588 obligations have been discharged, theorems of the expression are added
  2589 to the theory, target locale or proof context.  The synopsis of the
  2590 commands is a follows:
  2591 
  2592   (1) interpretation expr inst
  2593   (2) interpretation target < expr
  2594   (3) interpret expr inst
  2595 
  2596 Interpretation in theories and proof contexts require a parameter
  2597 instantiation of terms from the current context.  This is applied to
  2598 specifications and theorems of the interpreted expression.
  2599 Interpretation in locales only permits parameter renaming through the
  2600 locale expression.  Interpretation is smart in that interpretations
  2601 that are active already do not occur in proof obligations, neither are
  2602 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2603 inspect active interpretations of a particular locale.  For details,
  2604 see the Isar Reference manual.  Examples can be found in
  2605 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2606 
  2607 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2608 'interpret' instead.
  2609 
  2610 * New context element 'constrains' for adding type constraints to
  2611 parameters.
  2612 
  2613 * Context expressions: renaming of parameters with syntax
  2614 redeclaration.
  2615 
  2616 * Locale declaration: 'includes' disallowed.
  2617 
  2618 * Proper static binding of attribute syntax -- i.e. types / terms /
  2619 facts mentioned as arguments are always those of the locale definition
  2620 context, independently of the context of later invocations.  Moreover,
  2621 locale operations (renaming and type / term instantiation) are applied
  2622 to attribute arguments as expected.
  2623 
  2624 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2625 actual attributes; rare situations may require Attrib.attribute to
  2626 embed those attributes into Attrib.src that lack concrete syntax.
  2627 Attribute implementations need to cooperate properly with the static
  2628 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2629 Attrib.XXX_thm etc. already do the right thing without further
  2630 intervention.  Only unusual applications -- such as "where" or "of"
  2631 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2632 on the context and the facts involved -- may have to assign parsed
  2633 values to argument tokens explicitly.
  2634 
  2635 * Changed parameter management in theorem generation for long goal
  2636 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2637 theorem statement in rare situations.
  2638 
  2639 * Locale inspection command 'print_locale' omits notes elements.  Use
  2640 'print_locale!' to have them included in the output.
  2641 
  2642 
  2643 *** Provers ***
  2644 
  2645 * Provers/hypsubst.ML: improved version of the subst method, for
  2646 single-step rewriting: it now works in bound variable contexts. New is
  2647 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2648 rewrite a different subterm than the original subst method, which is
  2649 still available as 'simplesubst'.
  2650 
  2651 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2652 and quasi orders.
  2653 
  2654 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2655 reflexive-transitive closure of relations.
  2656 
  2657 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2658 limit (previously hard-coded with a value of 20) user-definable.
  2659 
  2660 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2661 is peformed already.  Object-logics merely need to finish their
  2662 initial simpset configuration as before.  INCOMPATIBILITY.
  2663 
  2664 
  2665 *** HOL ***
  2666 
  2667 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2668 
  2669   syntax (epsilon)
  2670     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2671 
  2672 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2673 and x-symbol; use option '-m epsilon' to get it actually printed.
  2674 Moreover, the mathematically important symbolic identifier \<epsilon>
  2675 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2676 
  2677 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2678 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2679 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2680 support corresponding Isar calculations.
  2681 
  2682 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2683 instead of ":".
  2684 
  2685 * theory SetInterval: changed the syntax for open intervals:
  2686 
  2687   Old       New
  2688   {..n(}    {..<n}
  2689   {)n..}    {n<..}
  2690   {m..n(}   {m..<n}
  2691   {)m..n}   {m<..n}
  2692   {)m..n(}  {m<..<n}
  2693 
  2694 The old syntax is still supported but will disappear in the next
  2695 release.  For conversion use the following Emacs search and replace
  2696 patterns (these are not perfect but work quite well):
  2697 
  2698   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2699   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2700 
  2701 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2702 equalities in commutative rings; method 'algebra' provides a generic
  2703 interface.
  2704 
  2705 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2706 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2707 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2708 be a tuple pattern.
  2709 
  2710 Some new syntax forms are available:
  2711 
  2712   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2713   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2714   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2715   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2716 
  2717 The latter form "\<Sum>x < k. e" used to be based on a separate
  2718 function "Summation", which has been discontinued.
  2719 
  2720 * theory Finite_Set: in structured induction proofs, the insert case
  2721 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2722 (insert F x)'.
  2723 
  2724 * The 'refute' command has been extended to support a much larger
  2725 fragment of HOL, including axiomatic type classes, constdefs and
  2726 typedefs, inductive datatypes and recursion.
  2727 
  2728 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2729 Requires zChaff with proof generation to be installed.  See
  2730 HOL/ex/SAT_Examples.thy for examples.
  2731 
  2732 * Datatype induction via method 'induct' now preserves the name of the
  2733 induction variable. For example, when proving P(xs::'a list) by
  2734 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2735 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2736 in unstructured proof scripts.
  2737 
  2738 * Reworked implementation of records.  Improved scalability for
  2739 records with many fields, avoiding performance problems for type
  2740 inference. Records are no longer composed of nested field types, but
  2741 of nested extension types. Therefore the record type only grows linear
  2742 in the number of extensions and not in the number of fields.  The
  2743 top-level (users) view on records is preserved.  Potential
  2744 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2745 old record representation. The type generated for a record is called
  2746 <record_name>_ext_type.
  2747 
  2748 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2749 proofs triggered by a record definition or a simproc (if
  2750 quick_and_dirty is enabled).  Definitions of large records can take
  2751 quite long.
  2752 
  2753 New simproc record_upd_simproc for simplification of multiple record
  2754 updates enabled by default.  Moreover, trivial updates are also
  2755 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2756 occasionally, since simplification is more powerful by default.
  2757 
  2758 * typedef: proper support for polymorphic sets, which contain extra
  2759 type-variables in the term.
  2760 
  2761 * Simplifier: automatically reasons about transitivity chains
  2762 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2763 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2764 old proofs break occasionally as simplification may now solve more
  2765 goals than previously.
  2766 
  2767 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2768 present.  Works for all partial orders (class "order"), in particular
  2769 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2770 just like y <= x.
  2771 
  2772 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2773 bound variable or a constant then the let is unfolded.  Otherwise
  2774 first a is simplified to b, and then f b is simplified to g. If
  2775 possible we abstract b from g arriving at "let x = b in h x",
  2776 otherwise we unfold the let and arrive at g.  The simproc can be
  2777 enabled/disabled by the reference use_let_simproc.  Potential
  2778 INCOMPATIBILITY since simplification is more powerful by default.
  2779 
  2780 * Classical reasoning: the meson method now accepts theorems as arguments.
  2781 
  2782 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2783 jobs to provide advice on the provability of subgoals.
  2784 
  2785 * Theory OrderedGroup and Ring_and_Field: various additions and
  2786 improvements to faciliate calculations involving equalities and
  2787 inequalities.
  2788 
  2789 The following theorems have been eliminated or modified
  2790 (INCOMPATIBILITY):
  2791 
  2792   abs_eq             now named abs_of_nonneg
  2793   abs_of_ge_0        now named abs_of_nonneg
  2794   abs_minus_eq       now named abs_of_nonpos
  2795   imp_abs_id         now named abs_of_nonneg
  2796   imp_abs_neg_id     now named abs_of_nonpos
  2797   mult_pos           now named mult_pos_pos
  2798   mult_pos_le        now named mult_nonneg_nonneg
  2799   mult_pos_neg_le    now named mult_nonneg_nonpos
  2800   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2801   mult_neg           now named mult_neg_neg
  2802   mult_neg_le        now named mult_nonpos_nonpos
  2803 
  2804 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2805      
  2806      zero_le_square
  2807      not_square_less_zero 
  2808 
  2809   The following lemmas have been deleted from Real/RealPow:
  2810   
  2811      realpow_zero_zero
  2812      realpow_two
  2813      realpow_less
  2814      zero_le_power
  2815      realpow_two_le
  2816      abs_realpow_two
  2817      realpow_two_abs     
  2818 
  2819 * Theory Parity: added rules for simplifying exponents.
  2820 
  2821 * Theory List:
  2822 
  2823 The following theorems have been eliminated or modified
  2824 (INCOMPATIBILITY):
  2825 
  2826   list_all_Nil       now named list_all.simps(1)
  2827   list_all_Cons      now named list_all.simps(2)
  2828   list_all_conv      now named list_all_iff
  2829   set_mem_eq         now named mem_iff
  2830 
  2831 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2832 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2833 
  2834 
  2835 *** HOL-Complex ***
  2836 
  2837 * Theory RealDef: better support for embedding natural numbers and
  2838 integers in the reals.
  2839 
  2840 The following theorems have been eliminated or modified
  2841 (INCOMPATIBILITY):
  2842 
  2843   exp_ge_add_one_self  now requires no hypotheses
  2844   real_of_int_add      reversed direction of equality (use [symmetric])
  2845   real_of_int_minus    reversed direction of equality (use [symmetric])
  2846   real_of_int_diff     reversed direction of equality (use [symmetric])
  2847   real_of_int_mult     reversed direction of equality (use [symmetric])
  2848 
  2849 * Theory RComplete: expanded support for floor and ceiling functions.
  2850 
  2851 * Theory Ln is new, with properties of the natural logarithm
  2852 
  2853 * Hyperreal: There is a new type constructor "star" for making
  2854 nonstandard types.  The old type names are now type synonyms:
  2855 
  2856   hypreal = real star
  2857   hypnat = nat star
  2858   hcomplex = complex star
  2859 
  2860 * Hyperreal: Many groups of similarly-defined constants have been
  2861 replaced by polymorphic versions (INCOMPATIBILITY):
  2862 
  2863   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2864 
  2865   starset      <-- starsetNat, starsetC
  2866   *s*          <-- *sNat*, *sc*
  2867   starset_n    <-- starsetNat_n, starsetC_n
  2868   *sn*         <-- *sNatn*, *scn*
  2869   InternalSets <-- InternalNatSets, InternalCSets
  2870 
  2871   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2872   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2873   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2874   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2875   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2876 
  2877 * Hyperreal: Many type-specific theorems have been removed in favor of
  2878 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2879 
  2880   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2881   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2882   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2883   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2884   right_minus <-- hypreal_add_minus
  2885   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2886   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2887   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2888   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2889   mult_1_right <-- hcomplex_mult_one_right
  2890   mult_zero_left <-- hcomplex_mult_zero_left
  2891   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2892   right_distrib <-- hypnat_add_mult_distrib2
  2893   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2894   right_inverse <-- hypreal_mult_inverse
  2895   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2896   order_refl <-- {hypreal,hypnat}_le_refl
  2897   order_trans <-- {hypreal,hypnat}_le_trans
  2898   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2899   order_less_le <-- {hypreal,hypnat}_less_le
  2900   linorder_linear <-- {hypreal,hypnat}_le_linear
  2901   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2902   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2903   add_nonneg_nonneg <-- hypreal_le_add_order
  2904 
  2905 * Hyperreal: Separate theorems having to do with type-specific
  2906 versions of constants have been merged into theorems that apply to the
  2907 new polymorphic constants (INCOMPATIBILITY):
  2908 
  2909   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2910   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2911   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2912   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2913   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2914   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2915   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2916   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2917   STAR_diff <-- {STAR,STARC}_diff
  2918   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2919     STARC_hcomplex_of_complex}_image_subset
  2920   starset_n_Un <-- starset{Nat,C}_n_Un
  2921   starset_n_Int <-- starset{Nat,C}_n_Int
  2922   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2923   starset_n_diff <-- starset{Nat,C}_n_diff
  2924   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2925   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2926   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2927   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2928   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2929   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2930   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2931   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2932   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2933   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2934   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2935   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2936   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2937   starfun_diff <-- starfun{C,RC,CR}_diff
  2938   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2939   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2940   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2941   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2942   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2943   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2944   starfun_Id <-- starfunC_Id
  2945   starfun_approx <-- starfun{Nat,CR}_approx
  2946   starfun_capprox <-- starfun{C,RC}_capprox
  2947   starfun_abs <-- starfunNat_rabs
  2948   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2949   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2950   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2951   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2952   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2953   starfun_add_approx <-- starfunCR_add_approx
  2954   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2955   starfun_divide <-- starfun{C,CR,RC}_divide
  2956   starfun_n <-- starfun{Nat,C}_n
  2957   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2958   starfun_n_add <-- starfun{Nat,C}_n_add
  2959   starfun_n_add_minus <-- starfunNat_n_add_minus
  2960   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2961   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2962   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2963 
  2964   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2965   star_n_minus <-- {hypreal,hcomplex}_minus
  2966   star_n_diff <-- {hypreal,hcomplex}_diff
  2967   star_n_mult <-- {hypreal,hcomplex}_mult
  2968   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2969   star_n_le <-- {hypreal,hypnat}_le
  2970   star_n_less <-- {hypreal,hypnat}_less
  2971   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2972   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2973   star_n_abs <-- hypreal_hrabs
  2974   star_n_divide <-- hcomplex_divide
  2975 
  2976   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2977   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2978   star_of_diff <-- hypreal_of_real_diff
  2979   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2980   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2981   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2982   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2983   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2984   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2985   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2986   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2987   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2988   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2989   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2990   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2991   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2992   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2993   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2994   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2995   star_of_power <-- hypreal_of_real_power
  2996   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2997 
  2998 * Hyperreal: new method "transfer" that implements the transfer
  2999 principle of nonstandard analysis. With a subgoal that mentions
  3000 nonstandard types like "'a star", the command "apply transfer"
  3001 replaces it with an equivalent one that mentions only standard types.
  3002 To be successful, all free variables must have standard types; non-
  3003 standard variables must have explicit universal quantifiers.
  3004 
  3005 * Hyperreal: A theory of Taylor series.
  3006 
  3007 
  3008 *** HOLCF ***
  3009 
  3010 * Discontinued special version of 'constdefs' (which used to support
  3011 continuous functions) in favor of the general Pure one with full
  3012 type-inference.
  3013 
  3014 * New simplification procedure for solving continuity conditions; it
  3015 is much faster on terms with many nested lambda abstractions (cubic
  3016 instead of exponential time).
  3017 
  3018 * New syntax for domain package: selector names are now optional.
  3019 Parentheses should be omitted unless argument is lazy, for example:
  3020 
  3021   domain 'a stream = cons "'a" (lazy "'a stream")
  3022 
  3023 * New command 'fixrec' for defining recursive functions with pattern
  3024 matching; defining multiple functions with mutual recursion is also
  3025 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3026 sinr, or any data constructor defined by the domain package. The given
  3027 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3028 syntax and examples.
  3029 
  3030 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3031 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3032 but the proof obligation additionally includes an admissibility
  3033 requirement. The packages generate instances of class cpo or pcpo,
  3034 with continuity and strictness theorems for Rep and Abs.
  3035 
  3036 * HOLCF: Many theorems have been renamed according to a more standard naming
  3037 scheme (INCOMPATIBILITY):
  3038 
  3039   foo_inject:  "foo$x = foo$y ==> x = y"
  3040   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3041   foo_less:    "(foo$x << foo$y) = (x << y)"
  3042   foo_strict:  "foo$UU = UU"
  3043   foo_defined: "... ==> foo$x ~= UU"
  3044   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3045 
  3046 
  3047 *** ZF ***
  3048 
  3049 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3050 including the First Isomorphism Theorem (on quotienting by the kernel
  3051 of a homomorphism).
  3052 
  3053 * ZF/Simplifier: install second copy of type solver that actually
  3054 makes use of TC rules declared to Isar proof contexts (or locales);
  3055 the old version is still required for ML proof scripts.
  3056 
  3057 
  3058 *** Cube ***
  3059 
  3060 * Converted to Isar theory format; use locales instead of axiomatic
  3061 theories.
  3062 
  3063 
  3064 *** ML ***
  3065 
  3066 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3067 for ||>, ||>>, |>>,
  3068 
  3069 * Pure/library.ML no longer defines its own option datatype, but uses
  3070 that of the SML basis, which has constructors NONE and SOME instead of
  3071 None and Some, as well as exception Option.Option instead of OPTION.
  3072 The functions the, if_none, is_some, is_none have been adapted
  3073 accordingly, while Option.map replaces apsome.
  3074 
  3075 * Pure/library.ML: the exception LIST has been given up in favour of
  3076 the standard exceptions Empty and Subscript, as well as
  3077 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3078 superceded by the standard hd and tl functions etc.
  3079 
  3080 A number of basic list functions are no longer exported to the ML
  3081 toplevel, as they are variants of predefined functions.  The following
  3082 suggests how one can translate existing code:
  3083 
  3084     rev_append xs ys = List.revAppend (xs, ys)
  3085     nth_elem (i, xs) = List.nth (xs, i)
  3086     last_elem xs = List.last xs
  3087     flat xss = List.concat xss
  3088     seq fs = List.app fs
  3089     partition P xs = List.partition P xs
  3090     mapfilter f xs = List.mapPartial f xs
  3091 
  3092 * Pure/library.ML: several combinators for linear functional
  3093 transformations, notably reverse application and composition:
  3094 
  3095   x |> f                f #> g
  3096   (x, y) |-> f          f #-> g
  3097 
  3098 * Pure/library.ML: introduced/changed precedence of infix operators:
  3099 
  3100   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3101   infix 2 ?;
  3102   infix 3 o oo ooo oooo;
  3103   infix 4 ~~ upto downto;
  3104 
  3105 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3106 infix operators.
  3107 
  3108 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3109 fold_map support linear functional transformations and nesting.  For
  3110 example:
  3111 
  3112   fold f [x1, ..., xN] y =
  3113     y |> f x1 |> ... |> f xN
  3114 
  3115   (fold o fold) f [xs1, ..., xsN] y =
  3116     y |> fold f xs1 |> ... |> fold f xsN
  3117 
  3118   fold f [x1, ..., xN] =
  3119     f x1 #> ... #> f xN
  3120 
  3121   (fold o fold) f [xs1, ..., xsN] =
  3122     fold f xs1 #> ... #> fold f xsN
  3123 
  3124 * Pure/library.ML: the following selectors on type 'a option are
  3125 available:
  3126 
  3127   the:               'a option -> 'a  (*partial*)
  3128   these:             'a option -> 'a  where 'a = 'b list
  3129   the_default: 'a -> 'a option -> 'a
  3130   the_list:          'a option -> 'a list
  3131 
  3132 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3133 basic operations for association lists, following natural argument
  3134 order; moreover the explicit equality predicate passed here avoids
  3135 potentially expensive polymorphic runtime equality checks.
  3136 The old functions may be expressed as follows:
  3137 
  3138   assoc = uncurry (AList.lookup (op =))
  3139   assocs = these oo AList.lookup (op =)
  3140   overwrite = uncurry (AList.update (op =)) o swap
  3141 
  3142 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3143 
  3144   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3145   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3146 
  3147 replacing make_keylist and keyfilter (occassionally used)
  3148 Naive rewrites:
  3149 
  3150   make_keylist = AList.make
  3151   keyfilter = AList.find (op =)
  3152 
  3153 * eq_fst and eq_snd now take explicit equality parameter, thus
  3154   avoiding eqtypes. Naive rewrites:
  3155 
  3156     eq_fst = eq_fst (op =)
  3157     eq_snd = eq_snd (op =)
  3158 
  3159 * Removed deprecated apl and apr (rarely used).
  3160   Naive rewrites:
  3161 
  3162     apl (n, op) =>>= curry op n
  3163     apr (op, m) =>>= fn n => op (n, m)
  3164 
  3165 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3166 provides a reasonably efficient light-weight implementation of sets as
  3167 lists.
  3168 
  3169 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3170 few new operations; existing lookup and update are now curried to
  3171 follow natural argument order (for use with fold etc.);
  3172 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3173 
  3174 * Pure/General: output via the Isabelle channels of
  3175 writeln/warning/error etc. is now passed through Output.output, with a
  3176 hook for arbitrary transformations depending on the print_mode
  3177 (cf. Output.add_mode -- the first active mode that provides a output
  3178 function wins).  Already formatted output may be embedded into further
  3179 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3180 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3181 accommodate easy composition of diagnostic messages etc.  Programmers
  3182 rarely need to care about Output.output or Output.raw at all, with
  3183 some notable exceptions: Output.output is required when bypassing the
  3184 standard channels (writeln etc.), or in token translations to produce
  3185 properly formatted results; Output.raw is required when capturing
  3186 already output material that will eventually be presented to the user
  3187 a second time.  For the default print mode, both Output.output and
  3188 Output.raw have no effect.
  3189 
  3190 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3191 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3192 cumulative results are displayed at the end of a batch session.
  3193 
  3194 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3195 replaced by File.platform_path and File.shell_path (with appropriate
  3196 hooks).  This provides a clean interface for unusual systems where the
  3197 internal and external process view of file names are different.
  3198 
  3199 * Pure: more efficient orders for basic syntactic entities: added
  3200 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3201 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3202 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3203 orders now -- potential INCOMPATIBILITY for code that depends on a
  3204 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3205 Library.sort_strings on result).
  3206 
  3207 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3208 fold_types traverse types/terms from left to right, observing natural
  3209 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3210 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3211 
  3212 * Pure: name spaces have been refined, with significant changes of the
  3213 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3214 to extern(_table).  The plain name entry path is superceded by a
  3215 general 'naming' context, which also includes the 'policy' to produce
  3216 a fully qualified name and external accesses of a fully qualified
  3217 name; NameSpace.extend is superceded by context dependent
  3218 Sign.declare_name.  Several theory and proof context operations modify
  3219 the naming context.  Especially note Theory.restore_naming and
  3220 ProofContext.restore_naming to get back to a sane state; note that
  3221 Theory.add_path is no longer sufficient to recover from
  3222 Theory.absolute_path in particular.
  3223 
  3224 * Pure: new flags short_names (default false) and unique_names
  3225 (default true) for controlling output of qualified names.  If
  3226 short_names is set, names are printed unqualified.  If unique_names is
  3227 reset, the name prefix is reduced to the minimum required to achieve
  3228 the original result when interning again, even if there is an overlap
  3229 with earlier declarations.
  3230 
  3231 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3232 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3233 (useful for printing error messages).  INCOMPATIBILITY.
  3234 
  3235 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3236 Theory.theory are now identified, referring to the universal
  3237 Context.theory (see Pure/context.ML).  Actual signature and theory
  3238 content is managed as theory data.  The old code and interfaces were
  3239 spread over many files and structures; the new arrangement introduces
  3240 considerable INCOMPATIBILITY to gain more clarity:
  3241 
  3242   Context -- theory management operations (name, identity, inclusion,
  3243     parents, ancestors, merge, etc.), plus generic theory data;
  3244 
  3245   Sign -- logical signature and syntax operations (declaring consts,
  3246     types, etc.), plus certify/read for common entities;
  3247 
  3248   Theory -- logical theory operations (stating axioms, definitions,
  3249     oracles), plus a copy of logical signature operations (consts,
  3250     types, etc.); also a few basic management operations (Theory.copy,
  3251     Theory.merge, etc.)
  3252 
  3253 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3254 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3255 for convenience -- they merely return the theory.
  3256 
  3257 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3258 
  3259 * Pure: the Isar proof context type is already defined early in Pure
  3260 as Context.proof (note that ProofContext.context and Proof.context are
  3261 aliases, where the latter is the preferred name).  This enables other
  3262 Isabelle components to refer to that type even before Isar is present.
  3263 
  3264 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3265 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3266 any of these kinds.  For example, Sign.intern typeK is now
  3267 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3268 Theory.hide_types.  Also note that former
  3269 Theory.hide_classes/types/consts are now
  3270 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3271 internalize their arguments!  INCOMPATIBILITY.
  3272 
  3273 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3274 datatype thmref (with constructors Name and NameSelection) instead of
  3275 plain string -- INCOMPATIBILITY;
  3276 
  3277 * Pure: cases produced by proof methods specify options, where NONE
  3278 means to remove case bindings -- INCOMPATIBILITY in
  3279 (RAW_)METHOD_CASES.
  3280 
  3281 * Pure: the following operations retrieve axioms or theorems from a
  3282 theory node or theory hierarchy, respectively:
  3283 
  3284   Theory.axioms_of: theory -> (string * term) list
  3285   Theory.all_axioms_of: theory -> (string * term) list
  3286   PureThy.thms_of: theory -> (string * thm) list
  3287   PureThy.all_thms_of: theory -> (string * thm) list
  3288 
  3289 * Pure: print_tac now outputs the goal through the trace channel.
  3290 
  3291 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3292 Reference Toplevel.debug (default false) controls detailed printing
  3293 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3294 controls execution profiling -- set to 1 for time and 2 for space
  3295 (both increase the runtime).
  3296 
  3297 * Isar session: The initial use of ROOT.ML is now always timed,
  3298 i.e. the log will show the actual process times, in contrast to the
  3299 elapsed wall-clock time that the outer shell wrapper produces.
  3300 
  3301 * Simplifier: improved handling of bound variables (nameless
  3302 representation, avoid allocating new strings).  Simprocs that invoke
  3303 the Simplifier recursively should use Simplifier.inherit_bounds to
  3304 avoid local name clashes.  Failure to do so produces warnings
  3305 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3306 for further details.
  3307 
  3308 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3309 bindings for all theorems stored within a given theory; this may help
  3310 in porting non-Isar theories to Isar ones, while keeping ML proof
  3311 scripts for the time being.
  3312 
  3313 * ML operator HTML.with_charset specifies the charset begin used for
  3314 generated HTML files.  For example:
  3315 
  3316   HTML.with_charset "utf-8" use_thy "Hebrew";
  3317   HTML.with_charset "utf-8" use_thy "Chinese";
  3318 
  3319 
  3320 *** System ***
  3321 
  3322 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3323 isabelle, isatool etc.).
  3324 
  3325 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3326 isatool doc, isatool mkdir, display_drafts etc.).
  3327 
  3328 * isatool usedir: option -f allows specification of the ML file to be
  3329 used by Isabelle; default is ROOT.ML.
  3330 
  3331 * New isatool version outputs the version identifier of the Isabelle
  3332 distribution being used.
  3333 
  3334 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3335 (containing Boolean satisfiability problems) into Isabelle/HOL
  3336 theories.
  3337 
  3338 
  3339 
  3340 New in Isabelle2004 (April 2004)
  3341 --------------------------------
  3342 
  3343 *** General ***
  3344 
  3345 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3346   Replaces linorder.ML.
  3347 
  3348 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3349   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3350   (\<a>...\<z>), are now considered normal letters, and can therefore
  3351   be used anywhere where an ASCII letter (a...zA...Z) has until
  3352   now. COMPATIBILITY: This obviously changes the parsing of some
  3353   terms, especially where a symbol has been used as a binder, say
  3354   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3355   as an identifier.  Fix it by inserting a space around former
  3356   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3357   existing theory and ML files.
  3358 
  3359 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3360 
  3361 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3362   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3363   a normal (but invisible) letter. For multiple letter subscripts repeat
  3364   \<^isub> like this: x\<^isub>1\<^isub>2.
  3365 
  3366 * Pure: There are now sub-/superscripts that can span more than one
  3367   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3368   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3369   superscript. The new control characters are not identifier parts.
  3370 
  3371 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3372   content of "..." to the latex file instead of \isacntrl... . The "..."
  3373   may consist of any printable characters excluding the end bracket >.
  3374 
  3375 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3376   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3377   declare constants "final", which prevents their being given a definition
  3378   later.  It is useful for constants whose behaviour is fixed axiomatically
  3379   rather than definitionally, such as the meta-logic connectives.
  3380 
  3381 * Pure: 'instance' now handles general arities with general sorts
  3382   (i.e. intersections of classes),
  3383 
  3384 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3385   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3386   It can be changed to alter the colors/layout of generated pages.
  3387 
  3388 
  3389 *** Isar ***
  3390 
  3391 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3392   cut_tac, subgoal_tac and thin_tac:
  3393   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3394     locales are no longer forced to write Isar proof scripts.
  3395     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3396     emulations.
  3397   - INCOMPATIBILITY: names of variables to be instantiated may no
  3398     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3399     This is consistent with the instantiation attribute "where".
  3400 
  3401 * Attributes "where" and "of":
  3402   - Now take type variables of instantiated theorem into account when reading
  3403     the instantiation string.  This fixes a bug that caused instantiated
  3404     theorems to have too special types in some circumstances.
  3405   - "where" permits explicit instantiations of type variables.
  3406 
  3407 * Calculation commands "moreover" and "also" no longer interfere with
  3408   current facts ("this"), admitting arbitrary combinations with "then"
  3409   and derived forms.
  3410 
  3411 * Locales:
  3412   - Goal statements involving the context element "includes" no longer
  3413     generate theorems with internal delta predicates (those ending on
  3414     "_axioms") in the premise.
  3415     Resolve particular premise with <locale>.intro to obtain old form.
  3416   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3417     specification and "includes" elements in goal statement.
  3418   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3419     [intro?] and [elim?] (respectively) by default.
  3420   - Experimental command for instantiation of locales in proof contexts:
  3421         instantiate <label>[<attrs>]: <loc>
  3422     Instantiates locale <loc> and adds all its theorems to the current context
  3423     taking into account their attributes.  Label and attrs are optional
  3424     modifiers, like in theorem declarations.  If present, names of
  3425     instantiated theorems are qualified with <label>, and the attributes
  3426     <attrs> are applied after any attributes these theorems might have already.
  3427       If the locale has assumptions, a chained fact of the form
  3428     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3429     are derived.  The command does not support old-style locales declared
  3430     with "locale (open)".
  3431       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3432 
  3433 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3434   (Isar) contexts.
  3435 
  3436 
  3437 *** HOL ***
  3438 
  3439 * Proof import: new image HOL4 contains the imported library from
  3440   the HOL4 system with about 2500 theorems. It is imported by
  3441   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3442   can be used like any other Isabelle image.  See
  3443   HOL/Import/HOL/README for more information.
  3444 
  3445 * Simplifier:
  3446   - Much improved handling of linear and partial orders.
  3447     Reasoners for linear and partial orders are set up for type classes
  3448     "linorder" and "order" respectively, and are added to the default simpset
  3449     as solvers.  This means that the simplifier can build transitivity chains
  3450     to solve goals from the assumptions.
  3451   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3452     of blast or auto after simplification become unnecessary because the goal
  3453     is solved by simplification already.
  3454 
  3455 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3456     all proved in axiomatic type classes for semirings, rings and fields.
  3457 
  3458 * Numerics:
  3459   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3460     now formalized using the Ring_and_Field theory mentioned above.
  3461   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3462     than before, because now they are set up once in a generic manner.
  3463   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3464     Look for the general versions in Ring_and_Field (and Power if they concern
  3465     exponentiation).
  3466 
  3467 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3468 
  3469 * Records:
  3470   - Record types are now by default printed with their type abbreviation
  3471     instead of the list of all field types. This can be configured via
  3472     the reference "print_record_type_abbr".
  3473   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3474     (not enabled by default).
  3475   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3476     EX x. x = sel r to True (not enabled by default).
  3477   - Tactic "record_split_simp_tac" to split and simplify records added.
  3478 
  3479 * 'specification' command added, allowing for definition by
  3480   specification.  There is also an 'ax_specification' command that
  3481   introduces the new constants axiomatically.
  3482 
  3483 * arith(_tac) is now able to generate counterexamples for reals as well.
  3484 
  3485 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3486 
  3487 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3488   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3489 
  3490 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3491   matrix theory to linear programming.
  3492 
  3493 * Unions and Intersections:
  3494   The latex output syntax of UN and INT has been changed
  3495   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3496   i.e. the index formulae has become a subscript.
  3497   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3498 
  3499 * Unions and Intersections over Intervals:
  3500   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3501   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3502   like in normal math, and corresponding versions for < and for intersection.
  3503 
  3504 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3505   lexicographic dictonary ordering has been added as "lexord".
  3506 
  3507 * ML: the legacy theory structures Int and List have been removed. They had
  3508   conflicted with ML Basis Library structures having the same names.
  3509 
  3510 * 'refute' command added to search for (finite) countermodels.  Only works
  3511   for a fragment of HOL.  The installation of an external SAT solver is
  3512   highly recommended.  See "HOL/Refute.thy" for details.
  3513 
  3514 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3515   formulae under an assignment of free variables to random values.
  3516   In contrast to 'refute', it can deal with inductive datatypes,
  3517   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3518   for examples.
  3519 
  3520 
  3521 *** HOLCF ***
  3522 
  3523 * Streams now come with concatenation and are part of the HOLCF image
  3524 
  3525 
  3526 
  3527 New in Isabelle2003 (May 2003)
  3528 ------------------------------
  3529 
  3530 *** General ***
  3531 
  3532 * Provers/simplifier:
  3533 
  3534   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3535     Assumptions are now subject to complete mutual simplification,
  3536     not just from left to right. The simplifier now preserves
  3537     the order of assumptions.
  3538 
  3539     Potential INCOMPATIBILITY:
  3540 
  3541     -- simp sometimes diverges where the old version did
  3542        not, e.g. invoking simp on the goal
  3543 
  3544         [| P (f x); y = x; f x = f y |] ==> Q
  3545 
  3546        now gives rise to the infinite reduction sequence
  3547 
  3548         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3549 
  3550        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3551        kind of problem.
  3552 
  3553     -- Tactics combining classical reasoner and simplification (such as auto)
  3554        are also affected by this change, because many of them rely on
  3555        simp. They may sometimes diverge as well or yield a different numbers
  3556        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3557        in case of problems. Sometimes subsequent calls to the classical
  3558        reasoner will fail because a preceeding call to the simplifier too
  3559        eagerly simplified the goal, e.g. deleted redundant premises.
  3560 
  3561   - The simplifier trace now shows the names of the applied rewrite rules
  3562 
  3563   - You can limit the number of recursive invocations of the simplifier
  3564     during conditional rewriting (where the simplifie tries to solve the
  3565     conditions before applying the rewrite rule):
  3566     ML "simp_depth_limit := n"
  3567     where n is an integer. Thus you can force termination where previously
  3568     the simplifier would diverge.
  3569 
  3570   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3571 
  3572   - No longer aborts on failed congruence proof.  Instead, the
  3573     congruence is ignored.
  3574 
  3575 * Pure: New generic framework for extracting programs from constructive
  3576   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3577   as HOL/Extraction for some case studies.
  3578 
  3579 * Pure: The main goal of the proof state is no longer shown by default, only
  3580 the subgoals. This behaviour is controlled by a new flag.
  3581    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3582 (ML: Proof.show_main_goal).
  3583 
  3584 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3585 rules whose conclusion matches subgoal 1:
  3586       PG menu: Isabelle/Isar -> Show me -> matching rules
  3587 The rules are ordered by how closely they match the subgoal.
  3588 In particular, rules that solve a subgoal outright are displayed first
  3589 (or rather last, the way they are printed).
  3590 (ML: ProofGeneral.print_intros())
  3591 
  3592 * Pure: New flag trace_unify_fail causes unification to print
  3593 diagnostic information (PG: in trace buffer) when it fails. This is
  3594 useful for figuring out why single step proofs like rule, erule or
  3595 assumption failed.
  3596 
  3597 * Pure: Locale specifications now produce predicate definitions
  3598 according to the body of text (covering assumptions modulo local
  3599 definitions); predicate "loc_axioms" covers newly introduced text,
  3600 while "loc" is cumulative wrt. all included locale expressions; the
  3601 latter view is presented only on export into the global theory
  3602 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3603 on the old view without predicates;
  3604 
  3605 * Pure: predefined locales "var" and "struct" are useful for sharing
  3606 parameters (as in CASL, for example); just specify something like
  3607 ``var x + var y + struct M'' as import;
  3608 
  3609 * Pure: improved thms_containing: proper indexing of facts instead of
  3610 raw theorems; check validity of results wrt. current name space;
  3611 include local facts of proof configuration (also covers active
  3612 locales), cover fixed variables in index; may use "_" in term
  3613 specification; an optional limit for the number of printed facts may
  3614 be given (the default is 40);
  3615 
  3616 * Pure: disallow duplicate fact bindings within new-style theory files
  3617 (batch-mode only);
  3618 
  3619 * Provers: improved induct method: assumptions introduced by case
  3620 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3621 the goal statement); "foo" still refers to all facts collectively;
  3622 
  3623 * Provers: the function blast.overloaded has been removed: all constants
  3624 are regarded as potentially overloaded, which improves robustness in exchange
  3625 for slight decrease in efficiency;
  3626 
  3627 * Provers/linorder: New generic prover for transitivity reasoning over
  3628 linear orders.  Note: this prover is not efficient!
  3629 
  3630 * Isar: preview of problems to finish 'show' now produce an error
  3631 rather than just a warning (in interactive mode);
  3632 
  3633 
  3634 *** HOL ***
  3635 
  3636 * arith(_tac)
  3637 
  3638  - Produces a counter example if it cannot prove a goal.
  3639    Note that the counter example may be spurious if the goal is not a formula
  3640    of quantifier-free linear arithmetic.
  3641    In ProofGeneral the counter example appears in the trace buffer.
  3642 
  3643  - Knows about div k and mod k where k is a numeral of type nat or int.
  3644 
  3645  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3646    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3647    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3648 
  3649 * simp's arithmetic capabilities have been enhanced a bit: it now
  3650 takes ~= in premises into account (by performing a case split);
  3651 
  3652 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3653 are distributed over a sum of terms;
  3654 
  3655 * New tactic "trans_tac" and method "trans" instantiate
  3656 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3657 "<=", "<" and "=").
  3658 
  3659 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3660 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3661 
  3662 * 'typedef' command has new option "open" to suppress the set
  3663 definition;
  3664 
  3665 * functions Min and Max on finite sets have been introduced (theory
  3666 Finite_Set);
  3667 
  3668 * attribute [symmetric] now works for relations as well; it turns
  3669 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3670 
  3671 * induct over a !!-quantified statement (say !!x1..xn):
  3672   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3673 
  3674 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3675 %x. None. Warning: empty_def now refers to the previously hidden definition
  3676 of the empty set.
  3677 
  3678 * Algebra: formalization of classical algebra.  Intended as base for
  3679 any algebraic development in Isabelle.  Currently covers group theory
  3680 (up to Sylow's theorem) and ring theory (Universal Property of
  3681 Univariate Polynomials).  Contributions welcome;
  3682 
  3683 * GroupTheory: deleted, since its material has been moved to Algebra;
  3684 
  3685 * Complex: new directory of the complex numbers with numeric constants,
  3686 nonstandard complex numbers, and some complex analysis, standard and
  3687 nonstandard (Jacques Fleuriot);
  3688 
  3689 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3690 
  3691 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3692 Fleuriot);
  3693 
  3694 * Real/HahnBanach: updated and adapted to locales;
  3695 
  3696 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3697 Gray and Kramer);
  3698 
  3699 * UNITY: added the Meier-Sanders theory of progress sets;
  3700 
  3701 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3702 as abstract algorithms, instantiated to the JVM;
  3703 
  3704 * Bali: Java source language formalization. Type system, operational
  3705 semantics, axiomatic semantics. Supported language features:
  3706 classes, interfaces, objects,virtual methods, static methods,
  3707 static/instance fields, arrays, access modifiers, definite
  3708 assignment, exceptions.
  3709 
  3710 
  3711 *** ZF ***
  3712 
  3713 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3714 universe, etc.);
  3715 
  3716 * Main ZF: virtually all theories converted to new-style format;
  3717 
  3718 
  3719 *** ML ***
  3720 
  3721 * Pure: Tactic.prove provides sane interface for internal proofs;
  3722 omits the infamous "standard" operation, so this is more appropriate
  3723 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3724 
  3725 * Pure: improved error reporting of simprocs;
  3726 
  3727 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3728 up simprocs;
  3729 
  3730 
  3731 *** Document preparation ***
  3732 
  3733 * uses \par instead of \\ for line breaks in theory text. This may
  3734 shift some page breaks in large documents. To get the old behaviour
  3735 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3736 
  3737 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3738 other packages
  3739 
  3740 * \<euro> now needs package babel/greek instead of marvosym (which
  3741 broke \Rightarrow)
  3742 
  3743 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3744 textcomp package)
  3745 
  3746 
  3747 
  3748 New in Isabelle2002 (March 2002)
  3749 --------------------------------
  3750 
  3751 *** Document preparation ***
  3752 
  3753 * greatly simplified document preparation setup, including more
  3754 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3755 instructive isatool mkdir; users should basically be able to get
  3756 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3757 users may run a separate document processing stage manually like this:
  3758 "isatool usedir -D output HOL Test && isatool document Test/output";
  3759 
  3760 * theory dependency graph may now be incorporated into documents;
  3761 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3762 with \includegraphics of LaTeX;
  3763 
  3764 * proper spacing of consecutive markup elements, especially text
  3765 blocks after section headings;
  3766 
  3767 * support bold style (for single symbols only), input syntax is like
  3768 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3769 
  3770 * \<bullet> is now output as bold \cdot by default, which looks much
  3771 better in printed text;
  3772 
  3773 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3774 note that these symbols are currently unavailable in Proof General /
  3775 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3776 
  3777 * isatool latex no longer depends on changed TEXINPUTS, instead
  3778 isatool document copies the Isabelle style files to the target
  3779 location;
  3780 
  3781 
  3782 *** Isar ***
  3783 
  3784 * Pure/Provers: improved proof by cases and induction;
  3785   - 'case' command admits impromptu naming of parameters (such as
  3786     "case (Suc n)");
  3787   - 'induct' method divinates rule instantiation from the inductive
  3788     claim; no longer requires excessive ?P bindings for proper
  3789     instantiation of cases;
  3790   - 'induct' method properly enumerates all possibilities of set/type
  3791     rules; as a consequence facts may be also passed through *type*
  3792     rules without further ado;
  3793   - 'induct' method now derives symbolic cases from the *rulified*
  3794     rule (before it used to rulify cases stemming from the internal
  3795     atomized version); this means that the context of a non-atomic
  3796     statement becomes is included in the hypothesis, avoiding the
  3797     slightly cumbersome show "PROP ?case" form;
  3798   - 'induct' may now use elim-style induction rules without chaining
  3799     facts, using ``missing'' premises from the goal state; this allows
  3800     rules stemming from inductive sets to be applied in unstructured
  3801     scripts, while still benefitting from proper handling of non-atomic
  3802     statements; NB: major inductive premises need to be put first, all
  3803     the rest of the goal is passed through the induction;
  3804   - 'induct' proper support for mutual induction involving non-atomic
  3805     rule statements (uses the new concept of simultaneous goals, see
  3806     below);
  3807   - append all possible rule selections, but only use the first
  3808     success (no backtracking);
  3809   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3810   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3811   - added 'print_induct_rules' (covered by help item in recent Proof
  3812     General versions);
  3813   - moved induct/cases attributes to Pure, methods to Provers;
  3814   - generic method setup instantiated for FOL and HOL;
  3815 
  3816 * Pure: support multiple simultaneous goal statements, for example
  3817 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3818 meta-level mechanism, this acts as if several individual goals had
  3819 been stated separately; in particular common proof methods need to be
  3820 repeated in order to cover all claims; note that a single elimination
  3821 step is *not* sufficient to establish the two conjunctions, so this
  3822 fails:
  3823 
  3824   assume "A & B" then have A and B ..   (*".." fails*)
  3825 
  3826 better use "obtain" in situations as above; alternative refer to
  3827 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3828 
  3829 * Pure: proper integration with ``locales''; unlike the original
  3830 version by Florian Kammller, Isar locales package high-level proof
  3831 contexts rather than raw logical ones (e.g. we admit to include
  3832 attributes everywhere); operations on locales include merge and
  3833 rename; support for implicit arguments (``structures''); simultaneous
  3834 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3835 some examples;
  3836 
  3837 * Pure: the following commands have been ``localized'', supporting a
  3838 target locale specification "(in name)": 'lemma', 'theorem',
  3839 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3840 stored both within the locale and at the theory level (exported and
  3841 qualified by the locale name);
  3842 
  3843 * Pure: theory goals may now be specified in ``long'' form, with
  3844 ad-hoc contexts consisting of arbitrary locale elements. for example
  3845 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3846 definitions may be given, too); the result is a meta-level rule with
  3847 the context elements being discharged in the obvious way;
  3848 
  3849 * Pure: new proof command 'using' allows to augment currently used
  3850 facts after a goal statement ('using' is syntactically analogous to
  3851 'apply', but acts on the goal's facts only); this allows chained facts
  3852 to be separated into parts given before and after a claim, as in
  3853 ``from a and b have C using d and e <proof>'';
  3854 
  3855 * Pure: renamed "antecedent" case to "rule_context";
  3856 
  3857 * Pure: new 'judgment' command records explicit information about the
  3858 object-logic embedding (used by several tools internally); no longer
  3859 use hard-wired "Trueprop";
  3860 
  3861 * Pure: added 'corollary' command;
  3862 
  3863 * Pure: fixed 'token_translation' command;
  3864 
  3865 * Pure: removed obsolete 'exported' attribute;
  3866 
  3867 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3868 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3869 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3870 
  3871 * Pure: method 'atomize' presents local goal premises as object-level
  3872 statements (atomic meta-level propositions); setup controlled via
  3873 rewrite rules declarations of 'atomize' attribute; example
  3874 application: 'induct' method with proper rule statements in improper
  3875 proof *scripts*;
  3876 
  3877 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3878 now consider the syntactic context of assumptions, giving a better
  3879 chance to get type-inference of the arguments right (this is
  3880 especially important for locales);
  3881 
  3882 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3883 mode;
  3884 
  3885 * Pure/obtain: the formal conclusion "thesis", being marked as
  3886 ``internal'', may no longer be reference directly in the text;
  3887 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3888 situations;
  3889 
  3890 * Pure: generic 'sym' attribute which declares a rule both as pure
  3891 'elim?' and for the 'symmetric' operation;
  3892 
  3893 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3894 text; the fixed correlation with particular command syntax has been
  3895 discontinued;
  3896 
  3897 * Pure: new method 'rules' is particularly well-suited for proof
  3898 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3899 but often produces more compact proof terms with less detours;
  3900 
  3901 * Pure/Provers/classical: simplified integration with pure rule
  3902 attributes and methods; the classical "intro?/elim?/dest?"
  3903 declarations coincide with the pure ones; the "rule" method no longer
  3904 includes classically swapped intros; "intro" and "elim" methods no
  3905 longer pick rules from the context; also got rid of ML declarations
  3906 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3907 INCOMPATIBILITY;
  3908 
  3909 * Provers/classical: attribute 'swapped' produces classical inversions
  3910 of introduction rules;
  3911 
  3912 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3913 rules instead of full simplifier context; 'iff' attribute handles
  3914 conditional rules;
  3915 
  3916 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3917 
  3918 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3919 "(permissive)" option to recover old behavior;
  3920 
  3921 * HOL: 'inductive' no longer features separate (collective) attributes
  3922 for 'intros' (was found too confusing);
  3923 
  3924 * HOL: properly declared induction rules less_induct and
  3925 wf_induct_rule;
  3926 
  3927 
  3928 *** HOL ***
  3929 
  3930 * HOL: moved over to sane numeral syntax; the new policy is as
  3931 follows:
  3932 
  3933   - 0 and 1 are polymorphic constants, which are defined on any
  3934   numeric type (nat, int, real etc.);
  3935 
  3936   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3937   binary representation internally;
  3938 
  3939   - type nat has special constructor Suc, and generally prefers Suc 0
  3940   over 1::nat and Suc (Suc 0) over 2::nat;
  3941 
  3942 This change may cause significant problems of INCOMPATIBILITY; here
  3943 are some hints on converting existing sources:
  3944 
  3945   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3946   entities, so expressions involving "-" (unary or binary minus) need
  3947   to be spaced properly;
  3948 
  3949   - existing occurrences of "1" may need to be constraint "1::nat" or
  3950   even replaced by Suc 0; similar for old "2";
  3951 
  3952   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3953 
  3954   - remove all special provisions on numerals in proofs;
  3955 
  3956 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3957 representation (depends on bin_arith_simps in the default context);
  3958 
  3959 * HOL: symbolic syntax for x^2 (numeral 2);
  3960 
  3961 * HOL: the class of all HOL types is now called "type" rather than
  3962 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3963 in axclass/classes, instance/arities, and (usually rare) occurrences
  3964 in typings (of consts etc.); internally the class is called
  3965 "HOL.type", ML programs should refer to HOLogic.typeS;
  3966 
  3967 * HOL/record package improvements:
  3968   - new derived operations "fields" to build a partial record section,
  3969     "extend" to promote a fixed record to a record scheme, and
  3970     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3971     declared as simp by default;
  3972   - shared operations ("more", "fields", etc.) now need to be always
  3973     qualified) --- potential INCOMPATIBILITY;
  3974   - removed "make_scheme" operations (use "make" with "extend") --
  3975     INCOMPATIBILITY;
  3976   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3977   - provides cases/induct rules for use with corresponding Isar
  3978     methods (for concrete records, record schemes, concrete more
  3979     parts, and schematic more parts -- in that order);
  3980   - internal definitions directly based on a light-weight abstract
  3981     theory of product types over typedef rather than datatype;
  3982 
  3983 * HOL: generic code generator for generating executable ML code from
  3984 specifications; specific support for HOL constructs such as inductive
  3985 datatypes and sets, as well as recursive functions; can be invoked
  3986 via 'generate_code' theory section;
  3987 
  3988 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3989 
  3990 * HOL: consolidated and renamed several theories.  In particular:
  3991         Ord.thy has been absorbed into HOL.thy
  3992         String.thy has been absorbed into List.thy
  3993 
  3994 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3995 (beware of argument permutation!);
  3996 
  3997 * HOL: linorder_less_split superseded by linorder_cases;
  3998 
  3999 * HOL/List: "nodups" renamed to "distinct";
  4000 
  4001 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4002 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4003   - Ex_def has changed, now need to use some_eq_ex
  4004 
  4005 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4006 in this (rare) case use:
  4007 
  4008   delSWrapper "split_all_tac"
  4009   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4010 
  4011 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4012 MAY FAIL;
  4013 
  4014 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4015 Isabelle's type classes, ^ on functions and relations has too general
  4016 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4017 necessary to attach explicit type constraints;
  4018 
  4019 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4020 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4021 renamed accordingly (eg "compI" -> "rel_compI").
  4022 
  4023 * HOL: syntax translations now work properly with numerals and records
  4024 expressions;
  4025 
  4026 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4027 of "lam" -- INCOMPATIBILITY;
  4028 
  4029 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4030 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4031 renamed "Product_Type.unit";
  4032 
  4033 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4034 
  4035 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4036 the "cases" method);
  4037 
  4038 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4039 Florian Kammller);
  4040 
  4041 * HOL/IMP: updated and converted to new-style theory format; several
  4042 parts turned into readable document, with proper Isar proof texts and
  4043 some explanations (by Gerwin Klein);
  4044 
  4045 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4046 
  4047 * HOL-Hyperreal is now a logic image;
  4048 
  4049 
  4050 *** HOLCF ***
  4051 
  4052 * Isar: consts/constdefs supports mixfix syntax for continuous
  4053 operations;
  4054 
  4055 * Isar: domain package adapted to new-style theory format, e.g. see
  4056 HOLCF/ex/Dnat.thy;
  4057 
  4058 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4059 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4060 lift.induct_tac, always use UU instead of Undef;
  4061 
  4062 * HOLCF/IMP: updated and converted to new-style theory;
  4063 
  4064 
  4065 *** ZF ***
  4066 
  4067 * Isar: proper integration of logic-specific tools and packages,
  4068 including theory commands '(co)inductive', '(co)datatype',
  4069 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4070 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4071 
  4072 * theory Main no longer includes AC; for the Axiom of Choice, base
  4073 your theory on Main_ZFC;
  4074 
  4075 * the integer library now covers quotients and remainders, with many
  4076 laws relating division to addition, multiplication, etc.;
  4077 
  4078 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4079 typeless version of the formalism;
  4080 
  4081 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4082 format;
  4083 
  4084 * ZF/Induct: new directory for examples of inductive definitions,
  4085 including theory Multiset for multiset orderings; converted to
  4086 new-style theory format;
  4087 
  4088 * ZF: many new theorems about lists, ordinals, etc.;
  4089 
  4090 
  4091 *** General ***
  4092 
  4093 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4094 variable proof controls level of detail: 0 = no proofs (only oracle
  4095 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4096 also ref manual for further ML interfaces;
  4097 
  4098 * Pure/axclass: removed obsolete ML interface
  4099 goal_subclass/goal_arity;
  4100 
  4101 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4102 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4103 separate tokens, so expressions involving minus need to be spaced
  4104 properly;
  4105 
  4106 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4107 rather than "infixl" or "infixr";
  4108 
  4109 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4110 sort constraint specifications in type inference; e.g. "x::_::foo"
  4111 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4112 type variable);
  4113 
  4114 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4115 control output of nested => (types); the default behavior is
  4116 "type_brackets";
  4117 
  4118 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4119 tokens into AST constants;
  4120 
  4121 * Pure/syntax: prefer later declarations of translations and print
  4122 translation functions; potential INCOMPATIBILITY: need to reverse
  4123 multiple declarations for same syntax element constant;
  4124 
  4125 * Pure/show_hyps reset by default (in accordance to existing Isar
  4126 practice);
  4127 
  4128 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4129 addSafter;
  4130 
  4131 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4132 as well;
  4133 
  4134 * system: tested support for MacOS X; should be able to get Isabelle +
  4135 Proof General to work in a plain Terminal after installing Poly/ML
  4136 (e.g. from the Isabelle distribution area) and GNU bash alone
  4137 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4138 support requires further installations, e.g. from
  4139 http://fink.sourceforge.net/);
  4140 
  4141 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4142 
  4143 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4144 of 40 MB), cf. ML_OPTIONS;
  4145 
  4146 * system: Proof General keywords specification is now part of the
  4147 Isabelle distribution (see etc/isar-keywords.el);
  4148 
  4149 * system: support for persistent Proof General sessions (refrain from
  4150 outdating all loaded theories on startup); user may create writable
  4151 logic images like this: ``isabelle -q HOL Test'';
  4152 
  4153 * system: smart selection of Isabelle process versus Isabelle
  4154 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4155 run both "isabelle" and "Isabelle" even if file names are badly
  4156 damaged (executable inspects the case of the first letter of its own
  4157 name); added separate "isabelle-process" and "isabelle-interface";
  4158 
  4159 * system: refrain from any attempt at filtering input streams; no
  4160 longer support ``8bit'' encoding of old isabelle font, instead proper
  4161 iso-latin characters may now be used; the related isatools
  4162 "symbolinput" and "nonascii" have disappeared as well;
  4163 
  4164 * system: removed old "xterm" interface (the print modes "xterm" and
  4165 "xterm_color" are still available for direct use in a suitable
  4166 terminal);
  4167 
  4168 
  4169 
  4170 New in Isabelle99-2 (February 2001)
  4171 -----------------------------------
  4172 
  4173 *** Overview of INCOMPATIBILITIES ***
  4174 
  4175 * HOL: please note that theories in the Library and elsewhere often use the
  4176 new-style (Isar) format; to refer to their theorems in an ML script you must
  4177 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4178 
  4179 * HOL: inductive package no longer splits induction rule aggressively,
  4180 but only as far as specified by the introductions given; the old
  4181 format may be recovered via ML function complete_split_rule or attribute
  4182 'split_rule (complete)';
  4183 
  4184 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4185 gfp_Tarski to gfp_unfold;
  4186 
  4187 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4188 
  4189 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4190 relation); infix "^^" has been renamed "``"; infix "``" has been
  4191 renamed "`"; "univalent" has been renamed "single_valued";
  4192 
  4193 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4194 operation;
  4195 
  4196 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4197 
  4198 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4199 
  4200 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4201 consequence, it is no longer monotonic wrt. the local goal context
  4202 (which is now passed through the inductive cases);
  4203 
  4204 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4205 \<gg> to \<ggreater>;
  4206 
  4207 
  4208 *** Document preparation ***
  4209 
  4210 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4211 available: are "it" for near math-mode best-style output, "sl" for
  4212 slanted text style, and "tt" for plain type-writer; if no
  4213 \isabellestyle command is given, output is according to slanted
  4214 type-writer);
  4215 
  4216 * support sub/super scripts (for single symbols only), input syntax is
  4217 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4218 
  4219 * some more standard symbols; see Appendix A of the system manual for
  4220 the complete list of symbols defined in isabellesym.sty;
  4221 
  4222 * improved isabelle style files; more abstract symbol implementation
  4223 (should now use \isamath{...} and \isatext{...} in custom symbol
  4224 definitions);
  4225 
  4226 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4227 state; Note that presentation of goal states does not conform to
  4228 actual human-readable proof documents.  Please do not include goal
  4229 states into document output unless you really know what you are doing!
  4230 
  4231 * proper indentation of antiquoted output with proportional LaTeX
  4232 fonts;
  4233 
  4234 * no_document ML operator temporarily disables LaTeX document
  4235 generation;
  4236 
  4237 * isatool unsymbolize tunes sources for plain ASCII communication;
  4238 
  4239 
  4240 *** Isar ***
  4241 
  4242 * Pure: Isar now suffers initial goal statements to contain unbound
  4243 schematic variables (this does not conform to actual readable proof
  4244 documents, due to unpredictable outcome and non-compositional proof
  4245 checking); users who know what they are doing may use schematic goals
  4246 for Prolog-style synthesis of proven results;
  4247 
  4248 * Pure: assumption method (an implicit finishing) now handles actual
  4249 rules as well;
  4250 
  4251 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4252 initial goal, declare "that" only as Pure intro (only for single
  4253 steps); the "that" rule assumption may now be involved in implicit
  4254 finishing, thus ".." becomes a feasible for trivial obtains;
  4255 
  4256 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4257 instance proofs may be performed by "..";
  4258 
  4259 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4260 statements as well;
  4261 
  4262 * Pure: more robust selection of calculational rules;
  4263 
  4264 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4265 rule (as well as the assumption rule);
  4266 
  4267 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4268 lemmas, using the graph browser tool;
  4269 
  4270 * Pure: predict failure of "show" in interactive mode;
  4271 
  4272 * Pure: 'thms_containing' now takes actual terms as arguments;
  4273 
  4274 * HOL: improved method 'induct' --- now handles non-atomic goals
  4275 (potential INCOMPATIBILITY); tuned error handling;
  4276 
  4277 * HOL: cases and induct rules now provide explicit hints about the
  4278 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4279 any remaining facts are inserted into the goal verbatim;
  4280 
  4281 * HOL: local contexts (aka cases) may now contain term bindings as
  4282 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4283 the result to be shown in each case;
  4284 
  4285 * HOL: added 'recdef_tc' command;
  4286 
  4287 * isatool convert assists in eliminating legacy ML scripts;
  4288 
  4289 
  4290 *** HOL ***
  4291 
  4292 * HOL/Library: a collection of generic theories to be used together
  4293 with main HOL; the theory loader path already includes this directory
  4294 by default; the following existing theories have been moved here:
  4295 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4296 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4297 
  4298 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4299 modelling and verification task performed in Isabelle/HOL +
  4300 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4301 
  4302 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4303 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4304 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4305 'domain', this makes the theory consistent with mathematical
  4306 literature;
  4307 
  4308 * HOL basics: added overloaded operations "inverse" and "divide"
  4309 (infix "/"), syntax for generic "abs" operation, generic summation
  4310 operator \<Sum>;
  4311 
  4312 * HOL/typedef: simplified package, provide more useful rules (see also
  4313 HOL/subset.thy);
  4314 
  4315 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4316 now expressed as a proper nested rule (old-style tactic scripts may
  4317 require atomize_strip_tac to cope with non-atomic premises);
  4318 
  4319 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4320 to "split_conv" (old name still available for compatibility);
  4321 
  4322 * HOL: improved concrete syntax for strings (e.g. allows translation
  4323 rules with string literals);
  4324 
  4325 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4326  and Fleuriot's mechanization of analysis, including the transcendental
  4327  functions for the reals;
  4328 
  4329 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4330 
  4331 
  4332 *** CTT ***
  4333 
  4334 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4335 "lam" is displayed as TWO lambda-symbols
  4336 
  4337 * CTT: theory Main now available, containing everything (that is, Bool
  4338 and Arith);
  4339 
  4340 
  4341 *** General ***
  4342 
  4343 * Pure: the Simplifier has been implemented properly as a derived rule
  4344 outside of the actual kernel (at last!); the overall performance
  4345 penalty in practical applications is about 50%, while reliability of
  4346 the Isabelle inference kernel has been greatly improved;
  4347 
  4348 * print modes "brackets" and "no_brackets" control output of nested =>
  4349 (types) and ==> (props); the default behaviour is "brackets";
  4350 
  4351 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4352 as assumptions as well;
  4353 
  4354 * system: support Poly/ML 4.0;
  4355 
  4356 * system: isatool install handles KDE version 1 or 2;
  4357 
  4358 
  4359 
  4360 New in Isabelle99-1 (October 2000)
  4361 ----------------------------------
  4362 
  4363 *** Overview of INCOMPATIBILITIES ***
  4364 
  4365 * HOL: simplification of natural numbers is much changed; to partly
  4366 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4367 issue the following ML commands:
  4368 
  4369   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4370   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4371 
  4372 * HOL: simplification no longer dives into case-expressions; this is
  4373 controlled by "t.weak_case_cong" for each datatype t;
  4374 
  4375 * HOL: nat_less_induct renamed to less_induct;
  4376 
  4377 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4378 fixsome to patch .thy and .ML sources automatically;
  4379 
  4380   select_equality  -> some_equality
  4381   select_eq_Ex     -> some_eq_ex
  4382   selectI2EX       -> someI2_ex
  4383   selectI2         -> someI2
  4384   selectI          -> someI
  4385   select1_equality -> some1_equality
  4386   Eps_sym_eq       -> some_sym_eq_trivial
  4387   Eps_eq           -> some_eq_trivial
  4388 
  4389 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4390 
  4391 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4392 instead);
  4393 
  4394 * HOL: the recursion equations generated by 'recdef' are now called
  4395 f.simps instead of f.rules;
  4396 
  4397 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4398 
  4399 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4400 sometimes be needed;
  4401 
  4402 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4403 
  4404 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4405 
  4406 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4407 product is now "<*>" instead of "Times"; the lexicographic product is
  4408 now "<*lex*>" instead of "**";
  4409 
  4410 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4411 of main HOL, but was unused); better use HOL's datatype package;
  4412 
  4413 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4414 the old syntax may be recovered as follows:
  4415 
  4416   syntax (symbols)
  4417     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4418       (infixl "\\<oplus>" 100)
  4419 
  4420 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4421 
  4422 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4423 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4424 internally;
  4425 
  4426 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4427 changed from A/r to A//r;
  4428 
  4429 * ZF: new treatment of arithmetic (nat & int) may break some old
  4430 proofs;
  4431 
  4432 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4433 rulify -> rule_format, elimify -> elim_format, ...);
  4434 
  4435 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4436 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4437 should have to change intro!! to intro? only); replaced "delrule" by
  4438 "rule del";
  4439 
  4440 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4441 
  4442 * Provers: strengthened force_tac by using new first_best_tac;
  4443 
  4444 * LaTeX document preparation: several changes of isabelle.sty (see
  4445 lib/texinputs);
  4446 
  4447 
  4448 *** Document preparation ***
  4449 
  4450 * formal comments (text blocks etc.) in new-style theories may now
  4451 contain antiquotations of thm/prop/term/typ/text to be presented
  4452 according to latex print mode; concrete syntax is like this:
  4453 @{term[show_types] "f(x) = a + x"};
  4454 
  4455 * isatool mkdir provides easy setup of Isabelle session directories,
  4456 including proper document sources;
  4457 
  4458 * generated LaTeX sources are now deleted after successful run
  4459 (isatool document -c); may retain a copy somewhere else via -D option
  4460 of isatool usedir;
  4461 
  4462 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4463 style files, achieving self-contained LaTeX sources and simplifying
  4464 LaTeX debugging;
  4465 
  4466 * old-style theories now produce (crude) LaTeX output as well;
  4467 
  4468 * browser info session directories are now self-contained (may be put
  4469 on WWW server seperately); improved graphs of nested sessions; removed
  4470 graph for 'all sessions';
  4471 
  4472 * several improvements in isabelle style files; \isabellestyle{it}
  4473 produces fake math mode output; \isamarkupheader is now \section by
  4474 default; see lib/texinputs/isabelle.sty etc.;
  4475 
  4476 
  4477 *** Isar ***
  4478 
  4479 * Isar/Pure: local results and corresponding term bindings are now
  4480 subject to Hindley-Milner polymorphism (similar to ML); this
  4481 accommodates incremental type-inference very nicely;
  4482 
  4483 * Isar/Pure: new derived language element 'obtain' supports
  4484 generalized existence reasoning;
  4485 
  4486 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4487 support accumulation of results, without applying any rules yet;
  4488 useful to collect intermediate results without explicit name
  4489 references, and for use with transitivity rules with more than 2
  4490 premises;
  4491 
  4492 * Isar/Pure: scalable support for case-analysis type proofs: new
  4493 'case' language element refers to local contexts symbolically, as
  4494 produced by certain proof methods; internally, case names are attached
  4495 to theorems as "tags";
  4496 
  4497 * Isar/Pure: theory command 'hide' removes declarations from
  4498 class/type/const name spaces;
  4499 
  4500 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4501 indicate potential overloading;
  4502 
  4503 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4504 
  4505 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4506 "{a,b,c}" instead of {a,b,c};
  4507 
  4508 * Isar/Pure now provides its own version of intro/elim/dest
  4509 attributes; useful for building new logics, but beware of confusion
  4510 with the version in Provers/classical;
  4511 
  4512 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4513 case name 'antecedent';
  4514 
  4515 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4516 to the current context is now done automatically);
  4517 
  4518 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4519 for definining proof methods in ML;
  4520 
  4521 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4522 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4523 most cases, one should have to change intro!! to intro? only);
  4524 replaced "delrule" by "rule del";
  4525 
  4526 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4527 'symmetric' attribute (the latter supercedes [RS sym]);
  4528 
  4529 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4530 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4531 well (including splits);
  4532 
  4533 * Isar/Provers: Simplifier and Classical methods now support all kind
  4534 of modifiers used in the past, including 'cong', 'iff', etc.
  4535 
  4536 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4537 of Simplifier and Classical reasoner);
  4538 
  4539 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4540 now support named cases; major packages (inductive, datatype, primrec,
  4541 recdef) support case names and properly name parameters;
  4542 
  4543 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4544 monotonicity conditions are extracted to be proven at end of
  4545 calculations;
  4546 
  4547 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4548 method anyway;
  4549 
  4550 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4551 split_if split_if_asm; datatype package provides theorems foo.splits =
  4552 foo.split foo.split_asm for each datatype;
  4553 
  4554 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4555 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4556 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4557 use "(cases (simplified))" method in proper proof texts);
  4558 
  4559 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4560 
  4561 * Isar: names of theorems etc. may be natural numbers as well;
  4562 
  4563 * Isar: 'pr' command: optional arguments for goals_limit and
  4564 ProofContext.prems_limit; no longer prints theory contexts, but only
  4565 proof states;
  4566 
  4567 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4568 additional print modes to be specified; e.g. "pr(latex)" will print
  4569 proof state according to the Isabelle LaTeX style;
  4570 
  4571 * Isar: improved support for emulating tactic scripts, including proof
  4572 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4573 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4574 (for HOL datatypes);
  4575 
  4576 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4577 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4578 'proof method scripts' have to be in depth-first order;
  4579 
  4580 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4581 
  4582 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4583 should instead use individual commands for printing items
  4584 (print_commands, print_methods etc.);
  4585 
  4586 * Isar: added 'nothing' --- the empty list of theorems;
  4587 
  4588 
  4589 *** HOL ***
  4590 
  4591 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4592 corresponding virtual machine and a specification of its bytecode
  4593 verifier and a lightweight bytecode verifier, including proofs of
  4594 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4595 Cornelia Pusch (see also the homepage of project Bali at
  4596 http://isabelle.in.tum.de/Bali/);
  4597 
  4598 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4599 Clemens Ballarin;
  4600 
  4601 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4602 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4603 Rasmussen;
  4604 
  4605 * HOL/Lattice: fundamental concepts of lattice theory and order
  4606 structures, including duals, properties of bounds versus algebraic
  4607 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4608 Theorem for complete lattices etc.; may also serve as a demonstration
  4609 for abstract algebraic reasoning using axiomatic type classes, and
  4610 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4611 
  4612 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4613 von Oheimb;
  4614 
  4615 * HOL/IMPP: extension of IMP with local variables and mutually
  4616 recursive procedures, by David von Oheimb;
  4617 
  4618 * HOL/Lambda: converted into new-style theory and document;
  4619 
  4620 * HOL/ex/Multiquote: example of multiple nested quotations and
  4621 anti-quotations -- basically a generalized version of de-Bruijn
  4622 representation; very useful in avoiding lifting of operations;
  4623 
  4624 * HOL/record: added general record equality rule to simpset; fixed
  4625 select-update simplification procedure to handle extended records as
  4626 well; admit "r" as field name;
  4627 
  4628 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4629 other numeric types and also as the identity of groups, rings, etc.;
  4630 
  4631 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4632 Types nat and int belong to this axclass;
  4633 
  4634 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4635    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4636    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4637   two terms #m*u and #n*u are replaced by #(m+n)*u
  4638     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4639   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4640     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4641 
  4642 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4643 powerful prover for predicate logic but knows nothing of clasets; see
  4644 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4645 
  4646 * HOL: new version of "case_tac" subsumes both boolean case split and
  4647 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4648 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4649 
  4650 * HOL: simplification no longer dives into case-expressions: only the
  4651 selector expression is simplified, but not the remaining arms; to
  4652 enable full simplification of case-expressions for datatype t, you may
  4653 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4654 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4655 
  4656 * HOL/recdef: the recursion equations generated by 'recdef' for
  4657 function 'f' are now called f.simps instead of f.rules; if all
  4658 termination conditions are proved automatically, these simplification
  4659 rules are added to the simpset, as in primrec; rules may be named
  4660 individually as well, resulting in a separate list of theorems for
  4661 each equation;
  4662 
  4663 * HOL/While is a new theory that provides a while-combinator. It
  4664 permits the definition of tail-recursive functions without the
  4665 provision of a termination measure. The latter is necessary once the
  4666 invariant proof rule for while is applied.
  4667 
  4668 * HOL: new (overloaded) notation for the set of elements below/above
  4669 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4670 
  4671 * HOL: theorems impI, allI, ballI bound as "strip";
  4672 
  4673 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4674 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4675 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4676 
  4677 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4678 
  4679 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4680 main HOL, but was unused);
  4681 
  4682 * HOL: fewer consts declared as global (e.g. have to refer to
  4683 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4684 
  4685 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4686 in case of overlap with user translations (e.g. judgements over
  4687 tuples); (note that the underlying logical represenation is still
  4688 bogus);
  4689 
  4690 
  4691 *** ZF ***
  4692 
  4693 * ZF: simplification automatically cancels common terms in arithmetic
  4694 expressions over nat and int;
  4695 
  4696 * ZF: new treatment of nat to minimize type-checking: all operators
  4697 coerce their operands to a natural number using the function natify,
  4698 making the algebraic laws unconditional;
  4699 
  4700 * ZF: as above, for int: operators coerce their operands to an integer
  4701 using the function intify;
  4702 
  4703 * ZF: the integer library now contains many of the usual laws for the
  4704 orderings, including $<=, and monotonicity laws for $+ and $*;
  4705 
  4706 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4707 simplification;
  4708 
  4709 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4710 to the simplifier and classical reasoner simultaneously;
  4711 
  4712 
  4713 *** General ***
  4714 
  4715 * Provers: blast_tac now handles actual object-logic rules as
  4716 assumptions; note that auto_tac uses blast_tac internally as well;
  4717 
  4718 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4719 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4720 
  4721 * Provers: delrules now handles destruct rules as well (no longer need
  4722 explicit make_elim);
  4723 
  4724 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4725   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4726 use instead the strong form,
  4727   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4728 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4729 from destruct-rules;
  4730 
  4731 * Provers: Simplifier.easy_setup provides a fast path to basic
  4732 Simplifier setup for new object-logics;
  4733 
  4734 * Pure: AST translation rules no longer require constant head on LHS;
  4735 
  4736 * Pure: improved name spaces: ambiguous output is qualified; support
  4737 for hiding of names;
  4738 
  4739 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4740 XSYMBOL_HOME; no longer need to do manual configuration in most
  4741 situations;
  4742 
  4743 * system: compression of ML heaps images may now be controlled via -c
  4744 option of isabelle and isatool usedir (currently only observed by
  4745 Poly/ML);
  4746 
  4747 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4748 useful for remote X11);
  4749 
  4750 * system: provide TAGS file for Isabelle sources;
  4751 
  4752 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4753 order;
  4754 
  4755 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4756 timing flag supersedes proof_timing and Toplevel.trace;
  4757 
  4758 * ML: new combinators |>> and |>>> for incremental transformations
  4759 with secondary results (e.g. certain theory extensions):
  4760 
  4761 * ML: PureThy.add_defs gets additional argument to indicate potential
  4762 overloading (usually false);
  4763 
  4764 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4765 results;
  4766 
  4767 
  4768 
  4769 New in Isabelle99 (October 1999)
  4770 --------------------------------
  4771 
  4772 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4773 
  4774 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4775 are no longer simplified.  (This allows the simplifier to unfold recursive
  4776 functional programs.)  To restore the old behaviour, declare
  4777 
  4778     Delcongs [if_weak_cong];
  4779 
  4780 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4781 complement;
  4782 
  4783 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4784 
  4785 * HOL/datatype: mutual_induct_tac no longer exists --
  4786   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4787 
  4788 * HOL/typedef: fixed type inference for representing set; type
  4789 arguments now have to occur explicitly on the rhs as type constraints;
  4790 
  4791 * ZF: The con_defs part of an inductive definition may no longer refer
  4792 to constants declared in the same theory;
  4793 
  4794 * HOL, ZF: the function mk_cases, generated by the inductive
  4795 definition package, has lost an argument.  To simplify its result, it
  4796 uses the default simpset instead of a supplied list of theorems.
  4797 
  4798 * HOL/List: the constructors of type list are now Nil and Cons;
  4799 
  4800 * Simplifier: the type of the infix ML functions
  4801         setSSolver addSSolver setSolver addSolver
  4802 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4803 for packaging solvers. A solver is created via
  4804         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4805 where the string argument is only a comment.
  4806 
  4807 
  4808 *** Proof tools ***
  4809 
  4810 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4811 decision procedure for linear arithmetic. Currently it is used for
  4812 types `nat', `int', and `real' in HOL (see below); it can, should and
  4813 will be instantiated for other types and logics as well.
  4814 
  4815 * The simplifier now accepts rewrite rules with flexible heads, eg
  4816      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4817   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4818   matching.
  4819 
  4820 
  4821 *** General ***
  4822 
  4823 * New Isabelle/Isar subsystem provides an alternative to traditional
  4824 tactical theorem proving; together with the ProofGeneral/isar user
  4825 interface it offers an interactive environment for developing human
  4826 readable proof documents (Isar == Intelligible semi-automated
  4827 reasoning); for further information see isatool doc isar-ref,
  4828 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4829 
  4830 * improved and simplified presentation of theories: better HTML markup
  4831 (including colors), graph views in several sizes; isatool usedir now
  4832 provides a proper interface for user theories (via -P option); actual
  4833 document preparation based on (PDF)LaTeX is available as well (for
  4834 new-style theories only); see isatool doc system for more information;
  4835 
  4836 * native support for Proof General, both for classic Isabelle and
  4837 Isabelle/Isar;
  4838 
  4839 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4840 using the graph browser tool;
  4841 
  4842 * Isabelle manuals now also available as PDF;
  4843 
  4844 * theory loader rewritten from scratch (may not be fully
  4845 bug-compatible); old loadpath variable has been replaced by show_path,
  4846 add_path, del_path, reset_path functions; new operations such as
  4847 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4848 isatool doc ref);
  4849 
  4850 * improved isatool install: option -k creates KDE application icon,
  4851 option -p DIR installs standalone binaries;
  4852 
  4853 * added ML_PLATFORM setting (useful for cross-platform installations);
  4854 more robust handling of platform specific ML images for SML/NJ;
  4855 
  4856 * the settings environment is now statically scoped, i.e. it is never
  4857 created again in sub-processes invoked from isabelle, isatool, or
  4858 Isabelle;
  4859 
  4860 * path element specification '~~' refers to '$ISABELLE_HOME';
  4861 
  4862 * in locales, the "assumes" and "defines" parts may be omitted if
  4863 empty;
  4864 
  4865 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4866 long arrows);
  4867 
  4868 * new print_mode "HTML";
  4869 
  4870 * new flag show_tags controls display of tags of theorems (which are
  4871 basically just comments that may be attached by some tools);
  4872 
  4873 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4874 mode and goal output format:
  4875 
  4876 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4877 244c244
  4878 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4879 ---
  4880 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4881 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4882 181c181
  4883 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4884 ---
  4885 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4886 
  4887 * function bind_thms stores lists of theorems (cf. bind_thm);
  4888 
  4889 * new shorthand tactics ftac, eatac, datac, fatac;
  4890 
  4891 * qed (and friends) now accept "" as result name; in that case the
  4892 theorem is not stored, but proper checks and presentation of the
  4893 result still apply;
  4894 
  4895 * theorem database now also indexes constants "Trueprop", "all",
  4896 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4897 
  4898 
  4899 *** HOL ***
  4900 
  4901 ** HOL arithmetic **
  4902 
  4903 * There are now decision procedures for linear arithmetic over nat and
  4904 int:
  4905 
  4906 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4907 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4908 are treated as atomic; subformulae not involving type `nat' or `int'
  4909 are ignored; quantified subformulae are ignored unless they are
  4910 positive universal or negative existential. The tactic has to be
  4911 invoked by hand and can be a little bit slow. In particular, the
  4912 running time is exponential in the number of occurrences of `min' and
  4913 `max', and `-' on `nat'.
  4914 
  4915 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4916 (negated) (in)equalities among the premises and the conclusion into
  4917 account (i.e. no compound formulae) and does not know about `min' and
  4918 `max', and `-' on `nat'. It is fast and is used automatically by the
  4919 simplifier.
  4920 
  4921 NB: At the moment, these decision procedures do not cope with mixed
  4922 nat/int formulae where the two parts interact, such as `m < n ==>
  4923 int(m) < int(n)'.
  4924 
  4925 * HOL/Numeral provides a generic theory of numerals (encoded
  4926 efficiently as bit strings); setup for types nat/int/real is in place;
  4927 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4928 int, existing theories and proof scripts may require a few additional
  4929 type constraints;
  4930 
  4931 * integer division and remainder can now be performed on constant
  4932 arguments;
  4933 
  4934 * many properties of integer multiplication, division and remainder
  4935 are now available;
  4936 
  4937 * An interface to the Stanford Validity Checker (SVC) is available through the
  4938 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4939 are proved automatically.  SVC must be installed separately, and its results
  4940 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4941 invocation of the underlying oracle).  For SVC see
  4942   http://verify.stanford.edu/SVC
  4943 
  4944 * IsaMakefile: the HOL-Real target now builds an actual image;
  4945 
  4946 
  4947 ** HOL misc **
  4948 
  4949 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4950 (in Isabelle/Isar) -- by Gertrud Bauer;
  4951 
  4952 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4953 analysis for assembly languages with subtypes;
  4954 
  4955 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4956 -- avoids syntactic ambiguities and treats state, transition, and
  4957 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4958 changed syntax and (many) tactics;
  4959 
  4960 * HOL/inductive: Now also handles more general introduction rules such
  4961   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4962   theorems are now maintained within the theory (maintained via the
  4963   "mono" attribute);
  4964 
  4965 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4966   (using function types) such as
  4967 
  4968   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4969 
  4970 * HOL/record: record_simproc (part of the default simpset) takes care
  4971 of selectors applied to updated records; record_split_tac is no longer
  4972 part of the default claset; update_defs may now be removed from the
  4973 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4974 
  4975   claset_ref () := claset() addSWrapper record_split_wrapper;
  4976   Delsimprocs [record_simproc]
  4977 
  4978 * HOL/typedef: fixed type inference for representing set; type
  4979 arguments now have to occur explicitly on the rhs as type constraints;
  4980 
  4981 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4982 names rather than an ML expression;
  4983 
  4984 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4985 supplied later.  Program schemes can be defined, such as
  4986     "While B C s = (if B s then While B C (C s) else s)"
  4987 where the well-founded relation can be chosen after B and C have been given.
  4988 
  4989 * HOL/List: the constructors of type list are now Nil and Cons;
  4990 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4991 course, ML tools referring to List.list.op # etc. have to be adapted;
  4992 
  4993 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4994 disabled by default; run isabelle with option -m HOL to get back to
  4995 the original Gordon/HOL-style output;
  4996 
  4997 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4998 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4999 
  5000 * HOL basic syntax simplified (more orthogonal): all variants of
  5001 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5002 Eps operator is provided as well: "SOME x. P[x]";
  5003 
  5004 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5005 
  5006 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5007 thus available for user theories;
  5008 
  5009 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5010 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5011 time;
  5012 
  5013 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5014 several times and then mp;
  5015 
  5016 
  5017 *** LK ***
  5018 
  5019 * the notation <<...>> is now available as a notation for sequences of
  5020 formulas;
  5021 
  5022 * the simplifier is now installed
  5023 
  5024 * the axiom system has been generalized (thanks to Soren Heilmann)
  5025 
  5026 * the classical reasoner now has a default rule database
  5027 
  5028 
  5029 *** ZF ***
  5030 
  5031 * new primrec section allows primitive recursive functions to be given
  5032 directly (as in HOL) over datatypes and the natural numbers;
  5033 
  5034 * new tactics induct_tac and exhaust_tac for induction (or case
  5035 analysis) over datatypes and the natural numbers;
  5036 
  5037 * the datatype declaration of type T now defines the recursor T_rec;
  5038 
  5039 * simplification automatically does freeness reasoning for datatype
  5040 constructors;
  5041 
  5042 * automatic type-inference, with AddTCs command to insert new
  5043 type-checking rules;
  5044 
  5045 * datatype introduction rules are now added as Safe Introduction rules
  5046 to the claset;
  5047 
  5048 * the syntax "if P then x else y" is now available in addition to
  5049 if(P,x,y);
  5050 
  5051 
  5052 *** Internal programming interfaces ***
  5053 
  5054 * tuned simplifier trace output; new flag debug_simp;
  5055 
  5056 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5057 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5058 
  5059 * AxClass.axclass_tac lost the theory argument;
  5060 
  5061 * tuned current_goals_markers semantics: begin / end goal avoids
  5062 printing empty lines;
  5063 
  5064 * removed prs and prs_fn hook, which was broken because it did not
  5065 include \n in its semantics, forcing writeln to add one
  5066 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5067 string -> unit if you really want to output text without newline;
  5068 
  5069 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5070 plain output, interface builders may have to enable 'isabelle_font'
  5071 mode to get Isabelle font glyphs as before;
  5072 
  5073 * refined token_translation interface; INCOMPATIBILITY: output length
  5074 now of type real instead of int;
  5075 
  5076 * theory loader actions may be traced via new ThyInfo.add_hook
  5077 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5078 your own database of information attached to *whole* theories -- as
  5079 opposed to intra-theory data slots offered via TheoryDataFun;
  5080 
  5081 * proper handling of dangling sort hypotheses (at last!);
  5082 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5083 extra sort hypotheses that can be witnessed from the type signature;
  5084 the force_strip_shyps flag is gone, any remaining shyps are simply
  5085 left in the theorem (with a warning issued by strip_shyps_warning);
  5086 
  5087 
  5088 
  5089 New in Isabelle98-1 (October 1998)
  5090 ----------------------------------
  5091 
  5092 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5093 
  5094 * several changes of automated proof tools;
  5095 
  5096 * HOL: major changes to the inductive and datatype packages, including
  5097 some minor incompatibilities of theory syntax;
  5098 
  5099 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5100 called `inj_on';
  5101 
  5102 * HOL: removed duplicate thms in Arith:
  5103   less_imp_add_less  should be replaced by  trans_less_add1
  5104   le_imp_add_le      should be replaced by  trans_le_add1
  5105 
  5106 * HOL: unary minus is now overloaded (new type constraints may be
  5107 required);
  5108 
  5109 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5110 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5111 now taken as an integer constant.
  5112 
  5113 * Pure: ML function 'theory_of' renamed to 'theory';
  5114 
  5115 
  5116 *** Proof tools ***
  5117 
  5118 * Simplifier:
  5119   1. Asm_full_simp_tac is now more aggressive.
  5120      1. It will sometimes reorient premises if that increases their power to
  5121         simplify.
  5122      2. It does no longer proceed strictly from left to right but may also
  5123         rotate premises to achieve further simplification.
  5124      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5125      old Asm_full_simp_tac in that it does not rotate premises.
  5126   2. The simplifier now knows a little bit about nat-arithmetic.
  5127 
  5128 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5129 allows for selected deletion of wrappers, by introduction of names for
  5130 wrapper functionals.  This implies that addbefore, addSbefore,
  5131 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5132 and that adding two tactics with the same name overwrites the first
  5133 one (emitting a warning).
  5134   type wrapper = (int -> tactic) -> (int -> tactic)
  5135   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5136   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5137   delWrapper, delSWrapper: claset *  string            -> claset
  5138   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5139 
  5140 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5141 semantics; addbefore now affects only the unsafe part of step_tac
  5142 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5143 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5144 by Force_tac;
  5145 
  5146 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5147 compWrapper; added safe wrapper (and access functions for it);
  5148 
  5149 * HOL/split_all_tac is now much faster and fails if there is nothing
  5150 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5151 and the names of the automatically generated variables have changed.
  5152 split_all_tac has moved within claset() from unsafe wrappers to safe
  5153 wrappers, which means that !!-bound variables are split much more
  5154 aggressively, and safe_tac and clarify_tac now split such variables.
  5155 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5156 Note: the same holds for record_split_tac, which does the job of
  5157 split_all_tac for record fields.
  5158 
  5159 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5160 permanently to the default simpset using Addsplits just like
  5161 Addsimps. They can be removed via Delsplits just like
  5162 Delsimps. Lower-case versions are also available.
  5163 
  5164 * HOL/Simplifier: The rule split_if is now part of the default
  5165 simpset. This means that the simplifier will eliminate all occurrences
  5166 of if-then-else in the conclusion of a goal. To prevent this, you can
  5167 either remove split_if completely from the default simpset by
  5168 `Delsplits [split_if]' or remove it in a specific call of the
  5169 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5170 other case splitting rules to/from the default simpset: every datatype
  5171 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5172 t is the name of the datatype).
  5173 
  5174 * Classical reasoner / Simplifier combination: new force_tac (and
  5175 derivatives Force_tac, force) combines rewriting and classical
  5176 reasoning (and whatever other tools) similarly to auto_tac, but is
  5177 aimed to solve the given subgoal completely.
  5178 
  5179 
  5180 *** General ***
  5181 
  5182 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5183 and `goalw': the theory is no longer needed as an explicit argument -
  5184 the current theory context is used; assumptions are no longer returned
  5185 at the ML-level unless one of them starts with ==> or !!; it is
  5186 recommended to convert to these new commands using isatool fixgoal
  5187 (backup your sources first!);
  5188 
  5189 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5190 the current theory context, and 'theory' to lookup stored theories;
  5191 
  5192 * new theory section 'locale' for declaring constants, assumptions and
  5193 definitions that have local scope;
  5194 
  5195 * new theory section 'nonterminals' for purely syntactic types;
  5196 
  5197 * new theory section 'setup' for generic ML setup functions
  5198 (e.g. package initialization);
  5199 
  5200 * the distribution now includes Isabelle icons: see
  5201 lib/logo/isabelle-{small,tiny}.xpm;
  5202 
  5203 * isatool install - install binaries with absolute references to
  5204 ISABELLE_HOME/bin;
  5205 
  5206 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5207 
  5208 * print mode 'emacs' reserved for Isamode;
  5209 
  5210 * support multiple print (ast) translations per constant name;
  5211 
  5212 * theorems involving oracles are now printed with a suffixed [!];
  5213 
  5214 
  5215 *** HOL ***
  5216 
  5217 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5218 
  5219 * HOL/inductive package reorganized and improved: now supports mutual
  5220 definitions such as
  5221 
  5222   inductive EVEN ODD
  5223     intrs
  5224       null "0 : EVEN"
  5225       oddI "n : EVEN ==> Suc n : ODD"
  5226       evenI "n : ODD ==> Suc n : EVEN"
  5227 
  5228 new theorem list "elims" contains an elimination rule for each of the
  5229 recursive sets; inductive definitions now handle disjunctive premises
  5230 correctly (also ZF);
  5231 
  5232 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5233 "mutual_induct" no longer exists - the induction rule is always
  5234 contained in "induct";
  5235 
  5236 
  5237 * HOL/datatype package re-implemented and greatly improved: now
  5238 supports mutually recursive datatypes such as
  5239 
  5240   datatype
  5241     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5242             | SUM ('a aexp) ('a aexp)
  5243             | DIFF ('a aexp) ('a aexp)
  5244             | NUM 'a
  5245   and
  5246     'a bexp = LESS ('a aexp) ('a aexp)
  5247             | AND ('a bexp) ('a bexp)
  5248             | OR ('a bexp) ('a bexp)
  5249 
  5250 as well as indirectly recursive datatypes such as
  5251 
  5252   datatype
  5253     ('a, 'b) term = Var 'a
  5254                   | App 'b ((('a, 'b) term) list)
  5255 
  5256 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5257 induction on mutually / indirectly recursive datatypes.
  5258 
  5259 Primrec equations are now stored in theory and can be accessed via
  5260 <function_name>.simps.
  5261 
  5262 INCOMPATIBILITIES:
  5263 
  5264   - Theories using datatypes must now have theory Datatype as an
  5265     ancestor.
  5266   - The specific <typename>.induct_tac no longer exists - use the
  5267     generic induct_tac instead.
  5268   - natE has been renamed to nat.exhaust - use exhaust_tac
  5269     instead of res_inst_tac ... natE. Note that the variable
  5270     names in nat.exhaust differ from the names in natE, this
  5271     may cause some "fragile" proofs to fail.
  5272   - The theorems split_<typename>_case and split_<typename>_case_asm
  5273     have been renamed to <typename>.split and <typename>.split_asm.
  5274   - Since default sorts of type variables are now handled correctly,
  5275     some datatype definitions may have to be annotated with explicit
  5276     sort constraints.
  5277   - Primrec definitions no longer require function name and type
  5278     of recursive argument.
  5279 
  5280 Consider using isatool fixdatatype to adapt your theories and proof
  5281 scripts to the new package (backup your sources first!).
  5282 
  5283 
  5284 * HOL/record package: considerably improved implementation; now
  5285 includes concrete syntax for record types, terms, updates; theorems
  5286 for surjective pairing and splitting !!-bound record variables; proof
  5287 support is as follows:
  5288 
  5289   1) standard conversions (selectors or updates applied to record
  5290 constructor terms) are part of the standard simpset;
  5291 
  5292   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5293 made part of standard simpset and claset via addIffs;
  5294 
  5295   3) a tactic for record field splitting (record_split_tac) is part of
  5296 the standard claset (addSWrapper);
  5297 
  5298 To get a better idea about these rules you may retrieve them via
  5299 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5300 the name of your record type.
  5301 
  5302 The split tactic 3) conceptually simplifies by the following rule:
  5303 
  5304   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5305 
  5306 Thus any record variable that is bound by meta-all will automatically
  5307 blow up into some record constructor term, consequently the
  5308 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5309 solve record problems automatically.
  5310 
  5311 
  5312 * reorganized the main HOL image: HOL/Integ and String loaded by
  5313 default; theory Main includes everything;
  5314 
  5315 * automatic simplification of integer sums and comparisons, using cancellation;
  5316 
  5317 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5318 
  5319 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5320 
  5321 * many new identities for unions, intersections, set difference, etc.;
  5322 
  5323 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5324 called split_if, split_split, split_sum_case and split_nat_case (to go
  5325 with add/delsplits);
  5326 
  5327 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5328 (?x::unit) = (); this is made part of the default simpset, which COULD
  5329 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5330 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5331 unit_abs_eta_conv is added in order to counter the effect of
  5332 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5333 %u.f();
  5334 
  5335 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5336 makes more sense);
  5337 
  5338 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5339   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5340   disjointness reasoning but breaking a few old proofs.
  5341 
  5342 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5343 to 'converse' from 'inverse' (for compatibility with ZF and some
  5344 literature);
  5345 
  5346 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5347 the well-founded relation;
  5348 
  5349 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5350     Compl A.  The "Compl" syntax remains available as input syntax for this
  5351     release ONLY.
  5352 
  5353 * HOL/Update: new theory of function updates:
  5354     f(a:=b) == %x. if x=a then b else f x
  5355 may also be iterated as in f(a:=b,c:=d,...);
  5356 
  5357 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5358 
  5359 * HOL/List:
  5360   - new function list_update written xs[i:=v] that updates the i-th
  5361     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5362   - new function `upt' written [i..j(] which generates the list
  5363     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5364     bound write [i..j], which is a shorthand for [i..j+1(].
  5365   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5366 
  5367 * HOL/Arith:
  5368   - removed 'pred' (predecessor) function;
  5369   - generalized some theorems about n-1;
  5370   - many new laws about "div" and "mod";
  5371   - new laws about greatest common divisors (see theory ex/Primes);
  5372 
  5373 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5374 instead of "inverse";
  5375 
  5376 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5377   of the multiset ordering;
  5378 
  5379 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5380   (not included by default);
  5381 
  5382 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5383 
  5384 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5385   programs, i.e. different program variables may have different types.
  5386 
  5387 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5388   [previously, this check worked only if the rewrite rule was unconditional]
  5389   Now rew can involve either definitions or equalities (either == or =).
  5390 
  5391 
  5392 *** ZF ***
  5393 
  5394 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5395   only the theorems proved on ZF.ML;
  5396 
  5397 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5398   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5399   disjointness reasoning but breaking a few old proofs.
  5400 
  5401 * ZF/Update: new theory of function updates
  5402     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5403   may also be iterated as in f(a:=b,c:=d,...);
  5404 
  5405 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5406 
  5407 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5408   [previously, this check worked only if the rewrite rule was unconditional]
  5409   Now rew can involve either definitions or equalities (either == or =).
  5410 
  5411 * case_tac provided for compatibility with HOL
  5412     (like the old excluded_middle_tac, but with subgoals swapped)
  5413 
  5414 
  5415 *** Internal programming interfaces ***
  5416 
  5417 * Pure: several new basic modules made available for general use, see
  5418 also src/Pure/README;
  5419 
  5420 * improved the theory data mechanism to support encapsulation (data
  5421 kind name replaced by private Object.kind, acting as authorization
  5422 key); new type-safe user interface via functor TheoryDataFun; generic
  5423 print_data function becomes basically useless;
  5424 
  5425 * removed global_names compatibility flag -- all theory declarations
  5426 are qualified by default;
  5427 
  5428 * module Pure/Syntax now offers quote / antiquote translation
  5429 functions (useful for Hoare logic etc. with implicit dependencies);
  5430 see HOL/ex/Antiquote for an example use;
  5431 
  5432 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5433 cterm -> thm;
  5434 
  5435 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5436 subgoal;
  5437 
  5438 * Display.print_goals function moved to Locale.print_goals;
  5439 
  5440 * standard print function for goals supports current_goals_markers
  5441 variable for marking begin of proof, end of proof, start of goal; the
  5442 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5443 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5444 for example;
  5445 
  5446 
  5447 
  5448 New in Isabelle98 (January 1998)
  5449 --------------------------------
  5450 
  5451 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5452 
  5453 * changed lexical syntax of terms / types: dots made part of long
  5454 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5455 
  5456 * simpset (and claset) reference variable replaced by functions
  5457 simpset / simpset_ref;
  5458 
  5459 * no longer supports theory aliases (via merge) and non-trivial
  5460 implicit merge of thms' signatures;
  5461 
  5462 * most internal names of constants changed due to qualified names;
  5463 
  5464 * changed Pure/Sequence interface (see Pure/seq.ML);
  5465 
  5466 
  5467 *** General Changes ***
  5468 
  5469 * hierachically structured name spaces (for consts, types, axms, thms
  5470 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5471 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5472 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5473 long_names for fully qualified output names; NOTE: ML programs
  5474 (special tactics, packages etc.) referring to internal names may have
  5475 to be adapted to cope with fully qualified names; in case of severe
  5476 backward campatibility problems try setting 'global_names' at compile
  5477 time to have enrything declared within a flat name space; one may also
  5478 fine tune name declarations in theories via the 'global' and 'local'
  5479 section;
  5480 
  5481 * reimplemented the implicit simpset and claset using the new anytype
  5482 data filed in signatures; references simpset:simpset ref etc. are
  5483 replaced by functions simpset:unit->simpset and
  5484 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5485 to patch your ML files accordingly;
  5486 
  5487 * HTML output now includes theory graph data for display with Java
  5488 applet or isatool browser; data generated automatically via isatool
  5489 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5490 
  5491 * defs may now be conditional; improved rewrite_goals_tac to handle
  5492 conditional equations;
  5493 
  5494 * defs now admits additional type arguments, using TYPE('a) syntax;
  5495 
  5496 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5497 creates a new theory node; implicit merge of thms' signatures is
  5498 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5499 transfer:theory->thm->thm in (rare) cases;
  5500 
  5501 * improved handling of draft signatures / theories; draft thms (and
  5502 ctyps, cterms) are automatically promoted to real ones;
  5503 
  5504 * slightly changed interfaces for oracles: admit many per theory, named
  5505 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5506 
  5507 * print_goals: optional output of const types (set show_consts and
  5508 show_types);
  5509 
  5510 * improved output of warnings (###) and errors (***);
  5511 
  5512 * subgoal_tac displays a warning if the new subgoal has type variables;
  5513 
  5514 * removed old README and Makefiles;
  5515 
  5516 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5517 
  5518 * removed obsolete init_pps and init_database;
  5519 
  5520 * deleted the obsolete tactical STATE, which was declared by
  5521     fun STATE tacfun st = tacfun st st;
  5522 
  5523 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5524 (which abbreviates $HOME);
  5525 
  5526 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5527 use isatool fixseq to adapt your ML programs (this works for fully
  5528 qualified references to the Sequence structure only!);
  5529 
  5530 * use_thy no longer requires writable current directory; it always
  5531 reloads .ML *and* .thy file, if either one is out of date;
  5532 
  5533 
  5534 *** Classical Reasoner ***
  5535 
  5536 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5537 tactics that use classical reasoning to simplify a subgoal without
  5538 splitting it into several subgoals;
  5539 
  5540 * Safe_tac: like safe_tac but uses the default claset;
  5541 
  5542 
  5543 *** Simplifier ***
  5544 
  5545 * added simplification meta rules:
  5546     (asm_)(full_)simplify: simpset -> thm -> thm;
  5547 
  5548 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5549 logics (again);
  5550 
  5551 * added prems argument to simplification procedures;
  5552 
  5553 * HOL, FOL, ZF: added infix function `addsplits':
  5554   instead of `<simpset> setloop (split_tac <thms>)'
  5555   you can simply write `<simpset> addsplits <thms>'
  5556 
  5557 
  5558 *** Syntax ***
  5559 
  5560 * TYPE('a) syntax for type reflection terms;
  5561 
  5562 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5563 
  5564 * pretty printer: changed order of mixfix annotation preference (again!);
  5565 
  5566 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5567 
  5568 
  5569 *** HOL ***
  5570 
  5571 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5572   with `addloop' of the simplifier to faciliate case splitting in premises.
  5573 
  5574 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5575 
  5576 * HOL/Auth: new protocol proofs including some for the Internet
  5577   protocol TLS;
  5578 
  5579 * HOL/Map: new theory of `maps' a la VDM;
  5580 
  5581 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5582 cancelling out common nat summands from =, <, <= (in)equalities, or
  5583 differences; simplification procedures nat_cancel_factor for
  5584 cancelling common factor from =, <, <= (in)equalities over natural
  5585 sums; nat_cancel contains both kinds of procedures, it is installed by
  5586 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5587 
  5588 * HOL/simplifier: terms of the form
  5589   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5590   are rewritten to
  5591   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5592   and those of the form
  5593   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5594   are rewritten to
  5595   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5596 
  5597 * HOL/datatype
  5598   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5599 
  5600   P(t_case f1 ... fn x) =
  5601      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5602         ...
  5603        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5604      )
  5605 
  5606   and a theorem `split_t_case_asm' of the form
  5607 
  5608   P(t_case f1 ... fn x) =
  5609     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5610         ...
  5611        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5612      )
  5613   which can be added to a simpset via `addsplits'. The existing theorems
  5614   expand_list_case and expand_option_case have been renamed to
  5615   split_list_case and split_option_case.
  5616 
  5617 * HOL/Arithmetic:
  5618   - `pred n' is automatically converted to `n-1'.
  5619     Users are strongly encouraged not to use `pred' any longer,
  5620     because it will disappear altogether at some point.
  5621   - Users are strongly encouraged to write "0 < n" rather than
  5622     "n ~= 0". Theorems and proof tools have been modified towards this
  5623     `standard'.
  5624 
  5625 * HOL/Lists:
  5626   the function "set_of_list" has been renamed "set" (and its theorems too);
  5627   the function "nth" now takes its arguments in the reverse order and
  5628   has acquired the infix notation "!" as in "xs!n".
  5629 
  5630 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5631 
  5632 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5633   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5634 
  5635 * HOL/record: extensible records with schematic structural subtyping
  5636 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5637 still lacks various theorems and concrete record syntax;
  5638 
  5639 
  5640 *** HOLCF ***
  5641 
  5642 * removed "axioms" and "generated by" sections;
  5643 
  5644 * replaced "ops" section by extended "consts" section, which is capable of
  5645   handling the continuous function space "->" directly;
  5646 
  5647 * domain package:
  5648   . proves theorems immediately and stores them in the theory,
  5649   . creates hierachical name space,
  5650   . now uses normal mixfix annotations (instead of cinfix...),
  5651   . minor changes to some names and values (for consistency),
  5652   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5653   . separator between mutual domain defs: changed "," to "and",
  5654   . improved handling of sort constraints;  now they have to
  5655     appear on the left-hand side of the equations only;
  5656 
  5657 * fixed LAM <x,y,zs>.b syntax;
  5658 
  5659 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5660 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5661 
  5662 
  5663 *** FOL and ZF ***
  5664 
  5665 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5666   with `addloop' of the simplifier to faciliate case splitting in premises.
  5667 
  5668 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5669 in HOL, they strip ALL and --> from proved theorems;
  5670 
  5671 
  5672 
  5673 New in Isabelle94-8 (May 1997)
  5674 ------------------------------
  5675 
  5676 *** General Changes ***
  5677 
  5678 * new utilities to build / run / maintain Isabelle etc. (in parts
  5679 still somewhat experimental); old Makefiles etc. still functional;
  5680 
  5681 * new 'Isabelle System Manual';
  5682 
  5683 * INSTALL text, together with ./configure and ./build scripts;
  5684 
  5685 * reimplemented type inference for greater efficiency, better error
  5686 messages and clean internal interface;
  5687 
  5688 * prlim command for dealing with lots of subgoals (an easier way of
  5689 setting goals_limit);
  5690 
  5691 
  5692 *** Syntax ***
  5693 
  5694 * supports alternative (named) syntax tables (parser and pretty
  5695 printer); internal interface is provided by add_modesyntax(_i);
  5696 
  5697 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5698 be used in conjunction with the Isabelle symbol font; uses the
  5699 "symbols" syntax table;
  5700 
  5701 * added token_translation interface (may translate name tokens in
  5702 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5703 the current print_mode); IMPORTANT: user print translation functions
  5704 are responsible for marking newly introduced bounds
  5705 (Syntax.mark_boundT);
  5706 
  5707 * token translations for modes "xterm" and "xterm_color" that display
  5708 names in bold, underline etc. or colors (which requires a color
  5709 version of xterm);
  5710 
  5711 * infixes may now be declared with names independent of their syntax;
  5712 
  5713 * added typed_print_translation (like print_translation, but may
  5714 access type of constant);
  5715 
  5716 
  5717 *** Classical Reasoner ***
  5718 
  5719 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5720 some limitations.  Blast_tac...
  5721   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5722   + ignores elimination rules that don't have the correct format
  5723         (the conclusion MUST be a formula variable)
  5724   + ignores types, which can make HOL proofs fail
  5725   + rules must not require higher-order unification, e.g. apply_type in ZF
  5726     [message "Function Var's argument not a bound variable" relates to this]
  5727   + its proof strategy is more general but can actually be slower
  5728 
  5729 * substitution with equality assumptions no longer permutes other
  5730 assumptions;
  5731 
  5732 * minor changes in semantics of addafter (now called addaltern); renamed
  5733 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5734 (and access functions for it);
  5735 
  5736 * improved combination of classical reasoner and simplifier:
  5737   + functions for handling clasimpsets
  5738   + improvement of addss: now the simplifier is called _after_ the
  5739     safe steps.
  5740   + safe variant of addss called addSss: uses safe simplifications
  5741     _during_ the safe steps. It is more complete as it allows multiple
  5742     instantiations of unknowns (e.g. with slow_tac).
  5743 
  5744 *** Simplifier ***
  5745 
  5746 * added interface for simplification procedures (functions that
  5747 produce *proven* rewrite rules on the fly, depending on current
  5748 redex);
  5749 
  5750 * ordering on terms as parameter (used for ordered rewriting);
  5751 
  5752 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5753 
  5754 * the solver is now split into a safe and an unsafe part.
  5755 This should be invisible for the normal user, except that the
  5756 functions setsolver and addsolver have been renamed to setSolver and
  5757 addSolver; added safe_asm_full_simp_tac;
  5758 
  5759 
  5760 *** HOL ***
  5761 
  5762 * a generic induction tactic `induct_tac' which works for all datatypes and
  5763 also for type `nat';
  5764 
  5765 * a generic case distinction tactic `exhaust_tac' which works for all
  5766 datatypes and also for type `nat';
  5767 
  5768 * each datatype comes with a function `size';
  5769 
  5770 * patterns in case expressions allow tuple patterns as arguments to
  5771 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5772 
  5773 * primrec now also works with type nat;
  5774 
  5775 * recdef: a new declaration form, allows general recursive functions to be
  5776 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5777 
  5778 * the constant for negation has been renamed from "not" to "Not" to
  5779 harmonize with FOL, ZF, LK, etc.;
  5780 
  5781 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5782 infinite lists;
  5783 
  5784 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5785 
  5786 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5787 problems in commutative rings, using axiomatic type classes for + and *;
  5788 
  5789 * more examples in HOL/MiniML and HOL/Auth;
  5790 
  5791 * more default rewrite rules for quantifiers, union/intersection;
  5792 
  5793 * a new constant `arbitrary == @x.False';
  5794 
  5795 * HOLCF/IOA replaces old HOL/IOA;
  5796 
  5797 * HOLCF changes: derived all rules and arities
  5798   + axiomatic type classes instead of classes
  5799   + typedef instead of faking type definitions
  5800   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5801   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5802   + eliminated the types void, one, tr
  5803   + use unit lift and bool lift (with translations) instead of one and tr
  5804   + eliminated blift from Lift3.thy (use Def instead of blift)
  5805   all eliminated rules are derived as theorems --> no visible changes ;
  5806 
  5807 
  5808 *** ZF ***
  5809 
  5810 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5811 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5812 as ZF_cs addSIs [equalityI];
  5813 
  5814 
  5815 
  5816 New in Isabelle94-7 (November 96)
  5817 ---------------------------------
  5818 
  5819 * allowing negative levels (as offsets) in prlev and choplev;
  5820 
  5821 * super-linear speedup for large simplifications;
  5822 
  5823 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5824 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5825 FAIL); can suppress it using the command Delsimps (ex_simps @
  5826 all_simps); De Morgan laws are also now included, by default;
  5827 
  5828 * improved printing of ==>  :  ~:
  5829 
  5830 * new object-logic "Sequents" adds linear logic, while replacing LK
  5831 and Modal (thanks to Sara Kalvala);
  5832 
  5833 * HOL/Auth: correctness proofs for authentication protocols;
  5834 
  5835 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5836 examples on HOL/Auth);
  5837 
  5838 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5839 the rewriter and classical reasoner simultaneously;
  5840 
  5841 * function uresult no longer returns theorems in "standard" format;
  5842 regain previous version by: val uresult = standard o uresult;
  5843 
  5844 
  5845 
  5846 New in Isabelle94-6
  5847 -------------------
  5848 
  5849 * oracles -- these establish an interface between Isabelle and trusted
  5850 external reasoners, which may deliver results as theorems;
  5851 
  5852 * proof objects (in particular record all uses of oracles);
  5853 
  5854 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5855 
  5856 * "constdefs" section in theory files;
  5857 
  5858 * "primrec" section (HOL) no longer requires names;
  5859 
  5860 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5861 
  5862 
  5863 
  5864 New in Isabelle94-5
  5865 -------------------
  5866 
  5867 * reduced space requirements;
  5868 
  5869 * automatic HTML generation from theories;
  5870 
  5871 * theory files no longer require "..." (quotes) around most types;
  5872 
  5873 * new examples, including two proofs of the Church-Rosser theorem;
  5874 
  5875 * non-curried (1994) version of HOL is no longer distributed;
  5876 
  5877 
  5878 
  5879 New in Isabelle94-4
  5880 -------------------
  5881 
  5882 * greatly reduced space requirements;
  5883 
  5884 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5885 
  5886 * searchable theorem database (see the section "Retrieving theorems" on
  5887 page 8 of the Reference Manual);
  5888 
  5889 * new examples, including Grabczewski's monumental case study of the
  5890 Axiom of Choice;
  5891 
  5892 * The previous version of HOL renamed to Old_HOL;
  5893 
  5894 * The new version of HOL (previously called CHOL) uses a curried syntax
  5895 for functions.  Application looks like f a b instead of f(a,b);
  5896 
  5897 * Mutually recursive inductive definitions finally work in HOL;
  5898 
  5899 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5900 translates to the operator "split";
  5901 
  5902 
  5903 
  5904 New in Isabelle94-3
  5905 -------------------
  5906 
  5907 * new infix operator, addss, allowing the classical reasoner to
  5908 perform simplification at each step of its search.  Example:
  5909         fast_tac (cs addss ss)
  5910 
  5911 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5912 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5913 look like (a,b) instead of <a,b>;
  5914 
  5915 * PLEASE NOTE: CHOL will eventually replace HOL!
  5916 
  5917 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5918 It translates to the operator "split".  A new theory of integers is available;
  5919 
  5920 * In ZF, integer numerals now denote two's-complement binary integers.
  5921 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5922 
  5923 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5924 of the Axiom of Choice;
  5925 
  5926 
  5927 
  5928 New in Isabelle94-2
  5929 -------------------
  5930 
  5931 * Significantly faster resolution;
  5932 
  5933 * the different sections in a .thy file can now be mixed and repeated
  5934 freely;
  5935 
  5936 * Database of theorems for FOL, HOL and ZF.  New
  5937 commands including qed, qed_goal and bind_thm store theorems in the database.
  5938 
  5939 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5940 a given theory (thms_of), or find out what theory a theorem was proved in
  5941 (theory_of_thm);
  5942 
  5943 * Bugs fixed in the inductive definition and datatype packages;
  5944 
  5945 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5946 and HOL_dup_cs obsolete;
  5947 
  5948 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5949 have been removed;
  5950 
  5951 * Simpler definition of function space in ZF;
  5952 
  5953 * new results about cardinal and ordinal arithmetic in ZF;
  5954 
  5955 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5956 types;
  5957 
  5958 :mode=text:wrap=hard:maxLineLen=72: