NEWS
author haftmann
Tue Nov 06 09:46:05 2007 +0100 (2007-11-06)
changeset 25305 574c4964fe54
parent 25199 e83c6c43f1e6
child 25397 82deaaba928d
permissions -rw-r--r--
added autoquickcheck
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in Isabelle2007
     5 -------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
    12 legacy features will disappear eventually.
    13 
    14 * Theory syntax: the header format ``theory A = B + C:'' has been
    15 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    16 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: the old non-Isar theory file format has been
    19 discontinued altogether.  Note that ML proof scripts may still be used
    20 with Isar theories; migration is usually quite simple with the ML
    21 function use_legacy_bindings.  INCOMPATIBILITY.
    22 
    23 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    24 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    25 quotes.
    26 
    27 * Theory loader: be more serious about observing the static theory
    28 header specifications (including optional directories), but not the
    29 accidental file locations of previously successful loads.  The strict
    30 update policy of former update_thy is now already performed by
    31 use_thy, so the former has been removed; use_thys updates several
    32 theories simultaneously, just as 'imports' within a theory header
    33 specification, but without merging the results.  Potential
    34 INCOMPATIBILITY: may need to refine theory headers and commands
    35 ROOT.ML which depend on load order.
    36 
    37 * Theory loader: optional support for content-based file
    38 identification, instead of the traditional scheme of full physical
    39 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
    40 (cf. the system manual).  The new scheme allows to work with
    41 non-finished theories in persistent session images, such that source
    42 files may be moved later on without requiring reloads.
    43 
    44 * Theory loader: old-style ML proof scripts being *attached* to a thy
    45 file (with the same base name as the theory) are considered a legacy
    46 feature, which will disappear eventually. Even now, the theory loader
    47 no longer maintains dependencies on such files.
    48 
    49 * Syntax: the scope for resolving ambiguities via type-inference is
    50 now limited to individual terms, instead of whole simultaneous
    51 specifications as before. This greatly reduces the complexity of the
    52 syntax module and improves flexibility by separating parsing and
    53 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
    54 'fixes' etc.) are required in rare situations.
    55 
    56 * Syntax: constants introduced by new-style packages ('definition',
    57 'abbreviation' etc.) are passed through the syntax module in
    58 ``authentic mode''. This means that associated mixfix annotations
    59 really stick to such constants, independently of potential name space
    60 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
    61 trees are represented slightly differently, may need to adapt syntax
    62 translations accordingly. Use CONST marker in 'translations' and
    63 @{const_syntax} antiquotation in 'parse_translation' etc.
    64 
    65 * Legacy goal package: reduced interface to the bare minimum required
    66 to keep existing proof scripts running.  Most other user-level
    67 functions are now part of the OldGoals structure, which is *not* open
    68 by default (consider isatool expandshort before open OldGoals).
    69 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    70 these tend to cause confusion about the actual goal (!) context being
    71 used here, which is not necessarily the same as the_context().
    72 
    73 * Command 'find_theorems': supports "*" wild-card in "name:"
    74 criterion; "with_dups" option.  Certain ProofGeneral versions might
    75 support a specific search form (see ProofGeneral/CHANGES).
    76 
    77 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    78 by default, which means that "prems" (and also "fixed variables") are
    79 suppressed from proof state output.  Note that the ProofGeneral
    80 settings mechanism allows to change and save options persistently, but
    81 older versions of Isabelle will fail to start up if a negative prems
    82 limit is imposed.
    83 
    84 * Local theory targets may be specified by non-nested blocks of
    85 ``context/locale/class ... begin'' followed by ``end''.  The body may
    86 contain definitions, theorems etc., including any derived mechanism
    87 that has been implemented on top of these primitives.  This concept
    88 generalizes the existing ``theorem (in ...)'' towards more versatility
    89 and scalability.
    90 
    91 * Proof General interface: proper undo of final 'end' command;
    92 discontinued Isabelle/classic mode (ML proof scripts).
    93 
    94 
    95 *** Document preparation ***
    96 
    97 * Added antiquotation @{theory name} which prints the given name,
    98 after checking that it refers to a valid ancestor theory in the
    99 current context.
   100 
   101 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   102 check the given source text as ML type/structure, printing verbatim.
   103 
   104 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   105 "c args == rhs" given in the current context.  (Any number of
   106 arguments may be given on the LHS.)
   107 
   108 
   109 
   110 *** Pure ***
   111 
   112 * The 'class' package offers a combination of axclass and locale to
   113 achieve Haskell-like type classes in Isabelle.  Definitions and
   114 theorems within a class context produce both relative results (with
   115 implicit parameters according to the locale context), and polymorphic
   116 constants with qualified polymorphism (according to the class
   117 context).  Within the body context of a 'class' target, a separate
   118 syntax layer ("user space type system") takes care of converting
   119 between global polymorphic consts and internal locale representation.
   120 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   121 "isatool doc classes" provides a tutorial.
   122 
   123 * Generic code generator framework allows to generate executable
   124 code for ML and Haskell (including Isabelle classes).  A short usage
   125 sketch:
   126 
   127     internal compilation:
   128         export_code <list of constants (term syntax)> in SML
   129     writing SML code to a file:
   130         export_code <list of constants (term syntax)> in SML <filename>
   131     writing OCaml code to a file:
   132         export_code <list of constants (term syntax)> in OCaml <filename>
   133     writing Haskell code to a bunch of files:
   134         export_code <list of constants (term syntax)> in Haskell <filename>
   135 
   136     evaluating closed propositions to True/False using code generation:
   137         method ``eval''
   138 
   139 Reasonable default setup of framework in HOL.
   140 
   141 Theorem attributs for selecting and transforming function equations theorems:
   142 
   143     [code fun]:        select a theorem as function equation for a specific constant
   144     [code fun del]:    deselect a theorem as function equation for a specific constant
   145     [code inline]:     select an equation theorem for unfolding (inlining) in place
   146     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   147 
   148 User-defined serializations (target in {SML, OCaml, Haskell}):
   149 
   150     code_const <and-list of constants (term syntax)>
   151       {(target) <and-list of const target syntax>}+
   152 
   153     code_type <and-list of type constructors>
   154       {(target) <and-list of type target syntax>}+
   155 
   156     code_instance <and-list of instances>
   157       {(target)}+
   158         where instance ::= <type constructor> :: <class>
   159 
   160     code_class <and_list of classes>
   161       {(target) <and-list of class target syntax>}+
   162         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   163 
   164 code_instance and code_class only are effective to target Haskell.
   165 
   166 For example usage see src/HOL/ex/Codegenerator.thy and
   167 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   168 generation from Isabelle/HOL theories is available via "isatool doc
   169 codegen".
   170 
   171 * Code generator: consts in 'consts_code' Isar commands are now
   172 referred to by usual term syntax (including optional type
   173 annotations).
   174 
   175 * Command 'no_translations' removes translation rules from theory
   176 syntax.
   177 
   178 * Overloaded definitions are now actually checked for acyclic
   179 dependencies.  The overloading scheme is slightly more general than
   180 that of Haskell98, although Isabelle does not demand an exact
   181 correspondence to type class and instance declarations.
   182 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   183 exotic versions of overloading -- at the discretion of the user!
   184 
   185 Polymorphic constants are represented via type arguments, i.e. the
   186 instantiation that matches an instance against the most general
   187 declaration given in the signature.  For example, with the declaration
   188 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   189 as c(nat).  Overloading is essentially simultaneous structural
   190 recursion over such type arguments.  Incomplete specification patterns
   191 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   192 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   193 Command 'print_theory' outputs the normalized system of recursive
   194 equations, see section "definitions".
   195 
   196 * Configuration options are maintained within the theory or proof
   197 context (with name and type bool/int/string), providing a very simple
   198 interface to a poor-man's version of general context data.  Tools may
   199 declare options in ML (e.g. using Attrib.config_int) and then refer to
   200 these values using Config.get etc.  Users may change options via an
   201 associated attribute of the same name.  This form of context
   202 declaration works particularly well with commands 'declare' or
   203 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   204 very easy to avoid global references, which would not observe Isar
   205 toplevel undo/redo and fail to work with multithreading.
   206 
   207 Various global ML references of Pure and HOL have been turned into
   208 configuration options:
   209 
   210   Unify.search_bound		unify_search_bound
   211   Unify.trace_bound		unify_trace_bound
   212   Unify.trace_simp		unify_trace_simp
   213   Unify.trace_types		unify_trace_types
   214   Simplifier.simp_depth_limit	simp_depth_limit
   215   Blast.depth_limit		blast_depth_limit
   216   DatatypeProp.dtK		datatype_distinctness_limit
   217   fast_arith_neq_limit  	fast_arith_neq_limit
   218   fast_arith_split_limit	fast_arith_split_limit
   219 
   220 * Named collections of theorems may be easily installed as context
   221 data using the functor NamedThmsFun (see also
   222 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   223 attributes; there is also a toplevel print command.  This facility is
   224 just a common case of general context data, which is the preferred way
   225 for anything more complex than just a list of facts in canonical
   226 order.
   227 
   228 * Isar: command 'declaration' augments a local theory by generic
   229 declaration functions written in ML.  This enables arbitrary content
   230 being added to the context, depending on a morphism that tells the
   231 difference of the original declaration context wrt. the application
   232 context encountered later on.
   233 
   234 * Isar: proper interfaces for simplification procedures.  Command
   235 'simproc_setup' declares named simprocs (with match patterns, and body
   236 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   237 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   238 
   239 * Isar: an extra pair of brackets around attribute declarations
   240 abbreviates a theorem reference involving an internal dummy fact,
   241 which will be ignored later --- only the effect of the attribute on
   242 the background context will persist.  This form of in-place
   243 declarations is particularly useful with commands like 'declare' and
   244 'using', for example ``have A using [[simproc a]] by simp''.
   245 
   246 * Isar: method "assumption" (and implicit closing of subproofs) now
   247 takes simple non-atomic goal assumptions into account: after applying
   248 an assumption as a rule the resulting subgoals are solved by atomic
   249 assumption steps.  This is particularly useful to finish 'obtain'
   250 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   251 without referring to the original premise "!!x. P x ==> thesis" in the
   252 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   253 more permissive.
   254 
   255 * Isar: implicit use of prems from the Isar proof context is
   256 considered a legacy feature.  Common applications like ``have A .''
   257 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   258 referencing facts explicitly here improves readability and
   259 maintainability of proof texts.
   260 
   261 * Isar: improper proof element 'guess' is like 'obtain', but derives
   262 the obtained context from the course of reasoning!  For example:
   263 
   264   assume "EX x y. A x & B y"   -- "any previous fact"
   265   then guess x and y by clarify
   266 
   267 This technique is potentially adventurous, depending on the facts and
   268 proof tools being involved here.
   269 
   270 * Isar: known facts from the proof context may be specified as literal
   271 propositions, using ASCII back-quote syntax.  This works wherever
   272 named facts used to be allowed so far, in proof commands, proof
   273 methods, attributes etc.  Literal facts are retrieved from the context
   274 according to unification of type and term parameters.  For example,
   275 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   276 theorems in the current context, then these are valid literal facts:
   277 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   278 
   279 There is also a proof method "fact" which does the same composition
   280 for explicit goal states, e.g. the following proof texts coincide with
   281 certain special cases of literal facts:
   282 
   283   have "A" by fact                 ==  note `A`
   284   have "A ==> B" by fact           ==  note `A ==> B`
   285   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   286   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   287 
   288 * Isar: ":" (colon) is no longer a symbolic identifier character in
   289 outer syntax.  Thus symbolic identifiers may be used without
   290 additional white space in declarations like this: ``assume *: A''.
   291 
   292 * Isar: 'print_facts' prints all local facts of the current context,
   293 both named and unnamed ones.
   294 
   295 * Isar: 'def' now admits simultaneous definitions, e.g.:
   296 
   297   def x == "t" and y == "u"
   298 
   299 * Isar: added command 'unfolding', which is structurally similar to
   300 'using', but affects both the goal state and facts by unfolding given
   301 rewrite rules.  Thus many occurrences of the 'unfold' method or
   302 'unfolded' attribute may be replaced by first-class proof text.
   303 
   304 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   305 and command 'unfolding' now all support object-level equalities
   306 (potentially conditional).  The underlying notion of rewrite rule is
   307 analogous to the 'rule_format' attribute, but *not* that of the
   308 Simplifier (which is usually more generous).
   309 
   310 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   311 premises of a theorem by n. Useful in conjunction with drule.
   312 
   313 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   314 method expression within a sandbox consisting of the first N
   315 sub-goals, which need to exist.  For example, ``simp_all [3]''
   316 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   317 simplifies all new goals that emerge from applying rule foo to the
   318 originally first one.
   319 
   320 * Isar: schematic goals are no longer restricted to higher-order
   321 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   322 expected.
   323 
   324 * Isar: the conclusion of a long theorem statement is now either
   325 'shows' (a simultaneous conjunction, as before), or 'obtains'
   326 (essentially a disjunction of cases with local parameters and
   327 assumptions).  The latter allows to express general elimination rules
   328 adequately; in this notation common elimination rules look like this:
   329 
   330   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   331     assumes "EX x. P x"
   332     obtains x where "P x"
   333 
   334   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   335     assumes "A & B"
   336     obtains A and B
   337 
   338   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   339     assumes "A | B"
   340     obtains
   341       A
   342     | B
   343 
   344 The subsequent classical rules even refer to the formal "thesis"
   345 explicitly:
   346 
   347   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   348     obtains "~ thesis"
   349 
   350   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   351     obtains "thesis ==> something"
   352 
   353 The actual proof of an 'obtains' statement is analogous to that of the
   354 Isar proof element 'obtain', only that there may be several cases.
   355 Optional case names may be specified in parentheses; these will be
   356 available both in the present proof and as annotations in the
   357 resulting rule, for later use with the 'cases' method (cf. attribute
   358 case_names).
   359 
   360 * Isar: the assumptions of a long theorem statement are available as
   361 "assms" fact in the proof context.  This is more appropriate than the
   362 (historical) "prems", which refers to all assumptions of the current
   363 context, including those from the target locale, proof body etc.
   364 
   365 * Isar: 'print_statement' prints theorems from the current theory or
   366 proof context in long statement form, according to the syntax of a
   367 top-level lemma.
   368 
   369 * Isar: 'obtain' takes an optional case name for the local context
   370 introduction rule (default "that").
   371 
   372 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   373 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   374 to occur.
   375 
   376 * Pure: syntax "CONST name" produces a fully internalized constant
   377 according to the current context.  This is particularly useful for
   378 syntax translations that should refer to internal constant
   379 representations independently of name spaces.
   380 
   381 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   382 instead of "FOO ". This allows multiple binder declarations to coexist
   383 in the same context.  INCOMPATIBILITY.
   384 
   385 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   386 primitive that also works in a locale context (both for constants and
   387 fixed variables). Type declaration and internal syntactic representation
   388 of given constants retrieved from the context. Likewise, the
   389 'no_notation' command allows to remove given syntax annotations from the
   390 current context.
   391 
   392 * Isar/locales: new derived specification elements 'axiomatization',
   393 'definition', 'abbreviation', which support type-inference, admit
   394 object-level specifications (equality, equivalence).  See also the
   395 isar-ref manual.  Examples:
   396 
   397   axiomatization
   398     eq  (infix "===" 50) where
   399     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   400 
   401   definition "f x y = x + y + 1"
   402   definition g where "g x = f x x"
   403 
   404   abbreviation
   405     neq  (infix "=!=" 50) where
   406     "x =!= y == ~ (x === y)"
   407 
   408 These specifications may be also used in a locale context.  Then the
   409 constants being introduced depend on certain fixed parameters, and the
   410 constant name is qualified by the locale base name.  An internal
   411 abbreviation takes care for convenient input and output, making the
   412 parameters implicit and using the original short name.  See also
   413 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   414 entities from a monomorphic theory.
   415 
   416 Presently, abbreviations are only available 'in' a target locale, but
   417 not inherited by general import expressions.  Also note that
   418 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   419 'translations' in common applications.  The "no_abbrevs" print mode
   420 prevents folding of abbreviations in term output.
   421 
   422 Concrete syntax is attached to specified constants in internal form,
   423 independently of name spaces.  The parse tree representation is
   424 slightly different -- use 'notation' instead of raw 'syntax', and
   425 'translations' with explicit "CONST" markup to accommodate this.
   426 
   427 * Pure/Isar: unified syntax for new-style specification mechanisms
   428 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   429 full type inference and dummy patterns ("_").  For example:
   430 
   431   definition "K x _ = x"
   432 
   433   inductive conj for A B
   434   where "A ==> B ==> conj A B"
   435 
   436 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   437 the current context.  Print mode "no_abbrevs" prevents inversion of
   438 abbreviations on output.
   439 
   440 * Isar/locales: improved parameter handling: use of locales "var" and
   441 "struct" no longer necessary; - parameter renamings are no longer
   442 required to be injective.  For example, this allows to define
   443 endomorphisms as locale endom = homom mult mult h.
   444 
   445 * Isar/locales: changed the way locales with predicates are defined.
   446 Instead of accumulating the specification, the imported expression is
   447 now an interpretation.  INCOMPATIBILITY: different normal form of
   448 locale expressions.  In particular, in interpretations of locales with
   449 predicates, goals repesenting already interpreted fragments are not
   450 removed automatically.  Use methods `intro_locales' and
   451 `unfold_locales'; see below.
   452 
   453 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   454 provide backward reasoning on locales predicates.  The methods are
   455 aware of interpretations and discharge corresponding goals.
   456 `intro_locales' is less aggressive then `unfold_locales' and does not
   457 unfold predicates to assumptions.
   458 
   459 * Isar/locales: the order in which locale fragments are accumulated
   460 has changed.  This enables to override declarations from fragments due
   461 to interpretations -- for example, unwanted simp rules.
   462 
   463 * Isar/locales: interpretation in theories and proof contexts has been
   464 extended.  One may now specify (and prove) equations, which are
   465 unfolded in interpreted theorems.  This is useful for replacing
   466 defined concepts (constants depending on locale parameters) by
   467 concepts already existing in the target context.  Example:
   468 
   469   interpretation partial_order ["op <= :: [int, int] => bool"]
   470     where "partial_order.less (op <=) (x::int) y = (x < y)"
   471 
   472 Typically, the constant `partial_order.less' is created by a
   473 definition specification element in the context of locale
   474 partial_order.
   475 
   476 * Method "induct": improved internal context management to support
   477 local fixes and defines on-the-fly. Thus explicit meta-level
   478 connectives !!  and ==> are rarely required anymore in inductive goals
   479 (using object-logic connectives for this purpose has been long
   480 obsolete anyway). Common proof patterns are explained in
   481 src/HOL/Induct/Common_Patterns.thy, see also
   482 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   483 examples.
   484 
   485 * Method "induct": improved handling of simultaneous goals. Instead of
   486 introducing object-level conjunction, the statement is now split into
   487 several conclusions, while the corresponding symbolic cases are nested
   488 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   489 see src/HOL/Induct/Common_Patterns.thy, for example.
   490 
   491 * Method "induct": mutual induction rules are now specified as a list
   492 of rule sharing the same induction cases. HOL packages usually provide
   493 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   494 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   495 mutual induction rules differently, i.e. like this:
   496 
   497   (induct rule: foo_bar.inducts)
   498   (induct set: foo bar)
   499   (induct pred: foo bar)
   500   (induct type: foo bar)
   501 
   502 The ML function ProjectRule.projections turns old-style rules into the
   503 new format.
   504 
   505 * Method "coinduct": dual of induction, see
   506 src/HOL/Library/Coinductive_List.thy for various examples.
   507 
   508 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   509 considered a legacy feature.
   510 
   511 * Attribute "symmetric" produces result with standardized schematic
   512 variables (index 0).  Potential INCOMPATIBILITY.
   513 
   514 * Simplifier: by default the simplifier trace only shows top level
   515 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   516 default. Thus there is less danger of being flooded by the trace. The
   517 trace indicates where parts have been suppressed.
   518   
   519 * Provers/classical: removed obsolete classical version of elim_format
   520 attribute; classical elim/dest rules are now treated uniformly when
   521 manipulating the claset.
   522 
   523 * Provers/classical: stricter checks to ensure that supplied intro,
   524 dest and elim rules are well-formed; dest and elim rules must have at
   525 least one premise.
   526 
   527 * Provers/classical: attributes dest/elim/intro take an optional
   528 weight argument for the rule (just as the Pure versions).  Weights are
   529 ignored by automated tools, but determine the search order of single
   530 rule steps.
   531 
   532 * Syntax: input syntax now supports dummy variable binding "%_. b",
   533 where the body does not mention the bound variable.  Note that dummy
   534 patterns implicitly depend on their context of bounds, which makes
   535 "{_. _}" match any set comprehension as expected.  Potential
   536 INCOMPATIBILITY -- parse translations need to cope with syntactic
   537 constant "_idtdummy" in the binding position.
   538 
   539 * Syntax: removed obsolete syntactic constant "_K" and its associated
   540 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   541 for example "A -> B" => "Pi A (%_. B)".
   542 
   543 * Pure: 'class_deps' command visualizes the subclass relation, using
   544 the graph browser tool.
   545 
   546 * Pure: 'print_theory' now suppresses certain internal declarations by
   547 default; use '!' option for full details.
   548 
   549 
   550 *** HOL ***
   551 
   552 * Method "metis" proves goals by applying the Metis general-purpose
   553 resolution prover (see also http://gilith.com/software/metis/).
   554 Examples are in the directory MetisExamples.  WARNING: the
   555 Isabelle/HOL-Metis integration does not yet work properly with
   556 multi-threading.
   557   
   558 * Command 'sledgehammer' invokes external automatic theorem provers as
   559 background processes.  It generates calls to the "metis" method if
   560 successful. These can be pasted into the proof.  Users do not have to
   561 wait for the automatic provers to return.  WARNING: does not really
   562 work with multi-threading.
   563 
   564 * New "auto_quickcheck" feature tests outermost goal statements for
   565 potential counter-examples.  Controlled by ML references
   566 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   567 5000 milliseconds).  Fails silently if statements is outside of
   568 executable fragment, or any other codgenerator problem occurs.
   569 
   570 * New constant "undefined" with axiom "undefined x = undefined".
   571 
   572 * Added class "HOL.eq", allowing for code generation with polymorphic
   573 equality.
   574 
   575 * Some renaming of class constants due to canonical name prefixing in
   576 the new 'class' package:
   577 
   578     HOL.abs ~> HOL.abs_class.abs
   579     HOL.divide ~> HOL.divide_class.divide
   580     0 ~> HOL.zero_class.zero
   581     1 ~> HOL.one_class.one
   582     op + ~> HOL.plus_class.plus
   583     op - ~> HOL.minus_class.minus
   584     uminus ~> HOL.minus_class.uminus
   585     op * ~> HOL.times_class.times
   586     op < ~> HOL.ord_class.less
   587     op <= > HOL.ord_class.less_eq
   588     Nat.power ~> Power.power_class.power
   589     Nat.size ~> Nat.size_class.size
   590     Numeral.number_of ~> Numeral.number_class.number_of
   591     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   592     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   593     Orderings.min ~> Orderings.ord_class.min
   594     Orderings.max ~> Orderings.ord_class.max
   595     Divides.op div ~> Divides.div_class.div
   596     Divides.op mod ~> Divides.div_class.mod
   597     Divides.op dvd ~> Divides.div_class.dvd
   598 
   599 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   600 
   601 a) User-defined constants using any of the names "plus", "minus",
   602 "times", "less" or "less_eq". The standard syntax translations for
   603 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   604 names.
   605 
   606 b) Variables named "plus", "minus", "times", "less", "less_eq"
   607 INCOMPATIBILITY: use more specific names.
   608 
   609 c) Permutative equations (e.g. "a + b = b + a")
   610 Since the change of names also changes the order of terms, permutative
   611 rewrite rules may get applied in a different order. Experience shows
   612 that this is rarely the case (only two adaptions in the whole Isabelle
   613 distribution).  INCOMPATIBILITY: rewrite proofs
   614 
   615 d) ML code directly refering to constant names
   616 This in general only affects hand-written proof tactics, simprocs and
   617 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   618 Consider using @{const_name} antiquotation.
   619 
   620 * New class "default" with associated constant "default".
   621 
   622 * Function "sgn" is now overloaded and available on int, real, complex
   623 (and other numeric types), using class "sgn".  Two possible defs of
   624 sgn are given as equational assumptions in the classes sgn_if and
   625 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   626 INCOMPATIBILITY.
   627 
   628 * Locale "partial_order" now unified with class "order" (cf. theory
   629 Orderings), added parameter "less".  INCOMPATIBILITY.
   630 
   631 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   632 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   633 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   634 
   635 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   636 changed order of proof goals in instance proofs.
   637 
   638 * The transitivity reasoner for partial and linear orders is set up
   639 for classes "order" and "linorder".  Instances of the reasoner are available
   640 in all contexts importing or interpreting the corresponding locales.
   641 Method "order" invokes the reasoner separately; the reasoner
   642 is also integrated with the Simplifier as a solver.  Diagnostic
   643 command 'print_orders' shows the available instances of the reasoner
   644 in the current context.
   645 
   646 * Localized monotonicity predicate in theory "Orderings"; integrated
   647 lemmas max_of_mono and min_of_mono with this predicate.
   648 INCOMPATIBILITY.
   649 
   650 * Formulation of theorem "dense" changed slightly due to integration
   651 with new class dense_linear_order.
   652 
   653 * Uniform lattice theory development in HOL.
   654 
   655     constants "meet" and "join" now named "inf" and "sup"
   656     constant "Meet" now named "Inf"
   657 
   658     classes "meet_semilorder" and "join_semilorder" now named
   659       "lower_semilattice" and "upper_semilattice"
   660     class "lorder" now named "lattice"
   661     class "comp_lat" now named "complete_lattice"
   662 
   663     Instantiation of lattice classes allows explicit definitions
   664     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   665 
   666   INCOMPATIBILITY.  Theorem renames:
   667 
   668     meet_left_le            ~> inf_le1
   669     meet_right_le           ~> inf_le2
   670     join_left_le            ~> sup_ge1
   671     join_right_le           ~> sup_ge2
   672     meet_join_le            ~> inf_sup_ord
   673     le_meetI                ~> le_infI
   674     join_leI                ~> le_supI
   675     le_meet                 ~> le_inf_iff
   676     le_join                 ~> ge_sup_conv
   677     meet_idempotent         ~> inf_idem
   678     join_idempotent         ~> sup_idem
   679     meet_comm               ~> inf_commute
   680     join_comm               ~> sup_commute
   681     meet_leI1               ~> le_infI1
   682     meet_leI2               ~> le_infI2
   683     le_joinI1               ~> le_supI1
   684     le_joinI2               ~> le_supI2
   685     meet_assoc              ~> inf_assoc
   686     join_assoc              ~> sup_assoc
   687     meet_left_comm          ~> inf_left_commute
   688     meet_left_idempotent    ~> inf_left_idem
   689     join_left_comm          ~> sup_left_commute
   690     join_left_idempotent    ~> sup_left_idem
   691     meet_aci                ~> inf_aci
   692     join_aci                ~> sup_aci
   693     le_def_meet             ~> le_iff_inf
   694     le_def_join             ~> le_iff_sup
   695     join_absorp2            ~> sup_absorb2
   696     join_absorp1            ~> sup_absorb1
   697     meet_absorp1            ~> inf_absorb1
   698     meet_absorp2            ~> inf_absorb2
   699     meet_join_absorp        ~> inf_sup_absorb
   700     join_meet_absorp        ~> sup_inf_absorb
   701     distrib_join_le         ~> distrib_sup_le
   702     distrib_meet_le         ~> distrib_inf_le
   703 
   704     add_meet_distrib_left   ~> add_inf_distrib_left
   705     add_join_distrib_left   ~> add_sup_distrib_left
   706     is_join_neg_meet        ~> is_join_neg_inf
   707     is_meet_neg_join        ~> is_meet_neg_sup
   708     add_meet_distrib_right  ~> add_inf_distrib_right
   709     add_join_distrib_right  ~> add_sup_distrib_right
   710     add_meet_join_distribs  ~> add_sup_inf_distribs
   711     join_eq_neg_meet        ~> sup_eq_neg_inf
   712     meet_eq_neg_join        ~> inf_eq_neg_sup
   713     add_eq_meet_join        ~> add_eq_inf_sup
   714     meet_0_imp_0            ~> inf_0_imp_0
   715     join_0_imp_0            ~> sup_0_imp_0
   716     meet_0_eq_0             ~> inf_0_eq_0
   717     join_0_eq_0             ~> sup_0_eq_0
   718     neg_meet_eq_join        ~> neg_inf_eq_sup
   719     neg_join_eq_meet        ~> neg_sup_eq_inf
   720     join_eq_if              ~> sup_eq_if
   721 
   722     mono_meet               ~> mono_inf
   723     mono_join               ~> mono_sup
   724     meet_bool_eq            ~> inf_bool_eq
   725     join_bool_eq            ~> sup_bool_eq
   726     meet_fun_eq             ~> inf_fun_eq
   727     join_fun_eq             ~> sup_fun_eq
   728     meet_set_eq             ~> inf_set_eq
   729     join_set_eq             ~> sup_set_eq
   730     meet1_iff               ~> inf1_iff
   731     meet2_iff               ~> inf2_iff
   732     meet1I                  ~> inf1I
   733     meet2I                  ~> inf2I
   734     meet1D1                 ~> inf1D1
   735     meet2D1                 ~> inf2D1
   736     meet1D2                 ~> inf1D2
   737     meet2D2                 ~> inf2D2
   738     meet1E                  ~> inf1E
   739     meet2E                  ~> inf2E
   740     join1_iff               ~> sup1_iff
   741     join2_iff               ~> sup2_iff
   742     join1I1                 ~> sup1I1
   743     join2I1                 ~> sup2I1
   744     join1I1                 ~> sup1I1
   745     join2I2                 ~> sup1I2
   746     join1CI                 ~> sup1CI
   747     join2CI                 ~> sup2CI
   748     join1E                  ~> sup1E
   749     join2E                  ~> sup2E
   750 
   751     is_meet_Meet            ~> is_meet_Inf
   752     Meet_bool_def           ~> Inf_bool_def
   753     Meet_fun_def            ~> Inf_fun_def
   754     Meet_greatest           ~> Inf_greatest
   755     Meet_lower              ~> Inf_lower
   756     Meet_set_def            ~> Inf_set_def
   757 
   758     Sup_def                 ~> Sup_Inf
   759     Sup_bool_eq             ~> Sup_bool_def
   760     Sup_fun_eq              ~> Sup_fun_def
   761     Sup_set_eq              ~> Sup_set_def
   762 
   763     listsp_meetI            ~> listsp_infI
   764     listsp_meet_eq          ~> listsp_inf_eq
   765 
   766     meet_min                ~> inf_min
   767     join_max                ~> sup_max
   768 
   769 * Added syntactic class "size"; overloaded constant "size" now has
   770 type "'a::size ==> bool"
   771 
   772 * Internal reorganisation of `size' of datatypes: size theorems
   773 "foo.size" are no longer subsumed by "foo.simps" (but are still
   774 simplification rules by default!); theorems "prod.size" now named
   775 "*.size".
   776 
   777 * Class "div" now inherits from class "times" rather than "type".
   778 INCOMPATIBILITY.
   779 
   780 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   781 Linorder etc.  have disappeared; operations defined in terms of
   782 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   783 
   784 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
   785 
   786 * HOL-Word: New extensive library and type for generic, fixed size
   787 machine words, with arithemtic, bit-wise, shifting and rotating
   788 operations, reflection into int, nat, and bool lists, automation for
   789 linear arithmetic (by automatic reflection into nat or int), including
   790 lemmas on overflow and monotonicity.  Instantiated to all appropriate
   791 arithmetic type classes, supporting automatic simplification of
   792 numerals on all operations.
   793 
   794 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   795 
   796 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   797 
   798 * Code generator library theories:
   799   - Code_Integer represents HOL integers by big integer literals in target
   800     languages.
   801   - Code_Char represents HOL characters by character literals in target
   802     languages.
   803   - Code_Char_chr like Code_Char, but also offers treatment of character
   804     codes; includes Code_Integer.
   805   - Executable_Set allows to generate code for finite sets using lists.
   806   - Executable_Rat implements rational numbers as triples (sign, enumerator,
   807     denominator).
   808   - Executable_Real implements a subset of real numbers, namly those
   809     representable by rational numbers.
   810   - Efficient_Nat implements natural numbers by integers, which in general will
   811     result in higher efficency; pattern matching with 0/Suc is eliminated;
   812     includes Code_Integer.
   813   - Code_Index provides an additional datatype index which is mapped to
   814     target-language built-in integers.
   815   - Code_Message provides an additional datatype message_string} which is isomorphic to
   816     strings; messages are mapped to target-language strings.
   817 
   818 * New package for inductive predicates
   819 
   820   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   821 
   822     inductive
   823       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   824       for z_1 :: U_1 and ... and z_n :: U_m
   825     where
   826       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   827     | ...
   828 
   829   with full support for type-inference, rather than
   830 
   831     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   832 
   833     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   834     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   835 
   836     inductive "s z_1 ... z_m"
   837     intros
   838       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   839       ...
   840 
   841   For backward compatibility, there is a wrapper allowing inductive
   842   sets to be defined with the new package via
   843 
   844     inductive_set
   845       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   846       for z_1 :: U_1 and ... and z_n :: U_m
   847     where
   848       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   849     | ...
   850 
   851   or
   852 
   853     inductive_set
   854       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   855       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   856       for z_1 :: U_1 and ... and z_n :: U_m
   857     where
   858       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   859     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   860     | ...
   861 
   862   if the additional syntax "p ..." is required.
   863 
   864   Numerous examples can be found in the subdirectories src/HOL/Auth,
   865   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
   866 
   867   INCOMPATIBILITIES:
   868 
   869   - Since declaration and definition of inductive sets or predicates
   870     is no longer separated, abbreviations involving the newly
   871     introduced sets or predicates must be specified together with the
   872     introduction rules after the 'where' keyword (see above), rather
   873     than before the actual inductive definition.
   874 
   875   - The variables in induction and elimination rules are now
   876     quantified in the order of their occurrence in the introduction
   877     rules, rather than in alphabetical order. Since this may break
   878     some proofs, these proofs either have to be repaired, e.g. by
   879     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
   880     statements of the form
   881 
   882       case (rule_i a_i_1 ... a_i_{k_i})
   883 
   884     or the old order of quantification has to be restored by explicitly adding
   885     meta-level quantifiers in the introduction rules, i.e.
   886 
   887       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   888 
   889   - The format of the elimination rules is now
   890 
   891       p z_1 ... z_m x_1 ... x_n ==>
   892         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   893         ==> ... ==> P
   894 
   895     for predicates and
   896 
   897       (x_1, ..., x_n) : s z_1 ... z_m ==>
   898         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   899         ==> ... ==> P
   900 
   901     for sets rather than
   902 
   903       x : s z_1 ... z_m ==>
   904         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   905         ==> ... ==> P
   906 
   907     This may require terms in goals to be expanded to n-tuples
   908     (e.g. using case_tac or simplification with the split_paired_all
   909     rule) before the above elimination rule is applicable.
   910 
   911   - The elimination or case analysis rules for (mutually) inductive
   912     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
   913     list of rules "p_1_..._p_k.elims" is no longer available.
   914 
   915 * New package "function"/"fun" for general recursive functions,
   916 supporting mutual and nested recursion, definitions in local contexts,
   917 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
   918 for small examples, and the separate tutorial on the function
   919 package. The old recdef "package" is still available as before, but
   920 users are encouraged to use the new package.
   921 
   922 * Method "lexicographic_order" automatically synthesizes termination
   923 relations as lexicographic combinations of size measures. 
   924 
   925 * Case-expressions allow arbitrary constructor-patterns (including
   926 "_") and take their order into account, like in functional
   927 programming.  Internally, this is translated into nested
   928 case-expressions; missing cases are added and mapped to the predefined
   929 constant "undefined". In complicated cases printing may no longer show
   930 the original input but the internal form. Lambda-abstractions allow
   931 the same form of pattern matching: "% pat1 => e1 | ..." is an
   932 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
   933 variable.
   934 
   935 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   936 is an abbreviation for "of_nat :: nat => int". The simplification
   937 rules for "of_nat" have been changed to work like "int" did
   938 previously.  Potential INCOMPATIBILITY:
   939   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   940   - of_nat_diff and of_nat_mult are no longer default simp rules
   941 
   942 * Method "algebra" solves polynomial equations over (semi)rings using
   943 Groebner bases. The (semi)ring structure is defined by locales and the
   944 tool setup depends on that generic context. Installing the method for
   945 a specific type involves instantiating the locale and possibly adding
   946 declarations for computation on the coefficients.  The method is
   947 already instantiated for natural numbers and for the axiomatic class
   948 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
   949 CALCULEMUS 2007 for the general principles underlying this
   950 architecture of context-aware proof-tools.
   951 
   952 * Method "ferrack" implements quantifier elimination over
   953 special-purpose dense linear orders using locales (analogous to
   954 "algebra"). The method is already installed for class
   955 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
   956 rat, etc.
   957 
   958 * Former constant "List.op @" now named "List.append".  Use ML
   959 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
   960 circumvent possible incompatibilities when working on ML level.
   961 
   962 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
   963 
   964 * New function listsum :: 'a list => 'a for arbitrary monoids.
   965 Special syntax: "SUM x <- xs. f x" (and latex variants)
   966 
   967 * New syntax for Haskell-like list comprehension (input only), eg.
   968 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
   969 
   970 * The special syntax for function "filter" has changed from [x :
   971 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
   972 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
   973 
   974 * [a..b] is now defined for arbitrary linear orders.  It used to be
   975 defined on nat only, as an abbreviation for [a..<Suc b]
   976 INCOMPATIBILITY.
   977 
   978 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
   979 
   980 * New functions "sorted" and "sort" in src/HOL/List.thy.
   981 
   982 * New lemma collection field_simps (an extension of ring_simps) for
   983 manipulating (in)equations involving division. Multiplies with all
   984 denominators that can be proved to be non-zero (in equations) or
   985 positive/negative (in inequations).
   986 
   987 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   988 have been improved and renamed to ring_simps, group_simps and
   989 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
   990 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
   991 
   992 * Theory Library/Commutative_Ring: switched from recdef to function
   993 package; constants add, mul, pow now curried.  Infix syntax for
   994 algebraic operations.
   995 
   996 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
   997 INCOMPATIBILITY.
   998 
   999 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1000 INCOMPATIBILITY.
  1001 
  1002 * HOL/records: generalised field-update to take a function on the
  1003 field rather than the new value: r(|A := x|) is translated to A_update
  1004 (K x) r The K-combinator that is internally used is called K_record.
  1005 INCOMPATIBILITY: Usage of the plain update functions has to be
  1006 adapted.
  1007  
  1008 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1009 * x = 0, which are required for a semiring.  Richer structures do not
  1010 inherit from semiring_0 anymore, because this property is a theorem
  1011 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1012 there is more to prove, but this is mostly trivial.
  1013 
  1014 * Class "recpower" is generalized to arbitrary monoids, not just
  1015 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1016 commutativity or semiring properties additionally.
  1017 
  1018 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1019 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1020 better use 'abbreviation'.
  1021 
  1022 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1023 
  1024 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1025 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1026 significant changes for setting up numeral syntax for types:
  1027   - New constants Numeral.pred and Numeral.succ instead
  1028       of former Numeral.bin_pred and Numeral.bin_succ.
  1029   - Use integer operations instead of bin_add, bin_mult and so on.
  1030   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1031   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1032 
  1033 See src/HOL/Integ/IntArith.thy for an example setup.
  1034 
  1035 * Command 'normal_form' computes the normal form of a term that may
  1036 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1037 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1038 heavy-duty computations because the functions are compiled to ML
  1039 first.  Correspondingly, a method "normalization" is provided.  See
  1040 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1041 
  1042 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1043 25 like -->); output depends on the "iff" print_mode, the default is
  1044 "A = B" (with priority 50).
  1045 
  1046 * Relations less (<) and less_eq (<=) are also available on type bool.
  1047 Modified syntax to disallow nesting without explicit parentheses,
  1048 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1049 INCOMPATIBILITY.
  1050 
  1051 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1052 
  1053 * Relation composition operator "op O" now has precedence 75 and binds
  1054 stronger than union and intersection. INCOMPATIBILITY.
  1055 
  1056 * The old set interval syntax "{m..n(}" (and relatives) has been
  1057 removed.  Use "{m..<n}" (and relatives) instead.
  1058 
  1059 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1060 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1061 ``declare [[simproc del: neq]]''.
  1062 
  1063 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1064 True/False.
  1065 
  1066 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1067 
  1068 * Theorem setsum_mult renamed to setsum_right_distrib.
  1069 
  1070 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1071 ``rule'' method.
  1072 
  1073 * Reimplemented methods "sat" and "satx", with several improvements:
  1074 goals no longer need to be stated as "<prems> ==> False", equivalences
  1075 (i.e. "=" on type bool) are handled, variable names of the form
  1076 "lit_<n>" are no longer reserved, significant speedup.
  1077 
  1078 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1079 zChaff is still supported as well.
  1080 
  1081 * 'inductive' and 'datatype': provide projections of mutual rules,
  1082 bundled as foo_bar.inducts;
  1083 
  1084 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1085 Library.
  1086 
  1087 * Library: moved theory Accessible_Part to main HOL.
  1088 
  1089 * Library: added theory Coinductive_List of potentially infinite lists
  1090 as greatest fixed-point.
  1091 
  1092 * Library: added theory AssocList which implements (finite) maps as
  1093 association lists.
  1094 
  1095 * Method "evaluation" solves goals (i.e. a boolean expression)
  1096 efficiently by compiling it to ML.  The goal is "proved" (via an
  1097 oracle) if it evaluates to True.
  1098 
  1099 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1100 also when invoked by the simplifier.  This results in the Simplifier
  1101 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1102 Configuration option fast_arith_split_limit=0 recovers the old
  1103 behavior.
  1104 
  1105 * Support for hex (0x20) and binary (0b1001) numerals.
  1106 
  1107 * New method: reify eqs (t), where eqs are equations for an
  1108 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1109 parameter, computes a term s::'b and a list xs::'a list and proves the
  1110 theorem I xs s = t. This is also known as reification or quoting. The
  1111 resulting theorem is applied to the subgoal to substitute t with I xs
  1112 s.  If t is omitted, the subgoal itself is reified.
  1113 
  1114 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1115 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1116 where f is supposed to be a computable function (in the sense of code
  1117 generattion). The method uses reify to compute s and xs as above then
  1118 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1119 r and finally gets the theorem t = r, which is again applied to the
  1120 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1121 
  1122 * Reflection: Automatic reification now handels binding, an example is
  1123 available in src/HOL/ex/ReflectionEx.thy
  1124 
  1125 
  1126 *** HOL-Complex ***
  1127 
  1128 * Hyperreal: Functions root and sqrt are now defined on negative real
  1129 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1130 Nonnegativity side conditions have been removed from many lemmas, so
  1131 that more subgoals may now be solved by simplification; potential
  1132 INCOMPATIBILITY.
  1133 
  1134 * Real: new type classes formalize real normed vector spaces and
  1135 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1136 and norm :: 'a => real.
  1137 
  1138 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1139 reals into other types. The overloaded constant Reals :: 'a set is now
  1140 defined as range of_real; potential INCOMPATIBILITY.
  1141 
  1142 * Real: proper support for ML code generation, including 'quickcheck'.
  1143 Reals are implemented as arbitrary precision rationals.
  1144 
  1145 * Hyperreal: Several constants that previously worked only for the
  1146 reals have been generalized, so they now work over arbitrary vector
  1147 spaces. Type annotations may need to be added in some cases; potential
  1148 INCOMPATIBILITY.
  1149 
  1150   Infinitesimal  :: ('a::real_normed_vector) star set
  1151   HFinite        :: ('a::real_normed_vector) star set
  1152   HInfinite      :: ('a::real_normed_vector) star set
  1153   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1154   monad          :: ('a::real_normed_vector) star => 'a star set
  1155   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1156   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1157   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1158   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1159   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1160   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1161   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1162   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1163   sgn            :: 'a::real_normed_vector => 'a
  1164   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1165 
  1166 * Complex: Some complex-specific constants are now abbreviations for
  1167 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1168 hnorm.  Other constants have been entirely removed in favor of the
  1169 polymorphic versions (INCOMPATIBILITY):
  1170 
  1171   approx        <-- capprox
  1172   HFinite       <-- CFinite
  1173   HInfinite     <-- CInfinite
  1174   Infinitesimal <-- CInfinitesimal
  1175   monad         <-- cmonad
  1176   galaxy        <-- cgalaxy
  1177   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1178   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1179   (ns)deriv     <-- (ns)cderiv
  1180 
  1181 
  1182 *** HOL-Algebra ***
  1183 
  1184 * Formalisation of ideals and the quotient construction over rings.
  1185 
  1186 * Order and lattice theory no longer based on records.
  1187 INCOMPATIBILITY.
  1188 
  1189 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1190 greatest_closed.  INCOMPATIBILITY.
  1191 
  1192 * Method algebra is now set up via an attribute.  For examples see
  1193 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1194 of algebraic structures.
  1195 
  1196 * Renamed theory CRing to Ring.
  1197 
  1198 
  1199 *** HOL-Nominal ***
  1200 
  1201 * Substantial, yet incomplete support for nominal datatypes (binding
  1202 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1203 src/HOL/Nominal/Examples.  Prospective users should consult
  1204 http://isabelle.in.tum.de/nominal/
  1205 
  1206 
  1207 *** ML ***
  1208 
  1209 * ML basics: just one true type int, which coincides with IntInf.int
  1210 (even on SML/NJ).
  1211 
  1212 * ML within Isar: antiquotations allow to embed statically-checked
  1213 formal entities in the source, referring to the context available at
  1214 compile-time.  For example:
  1215 
  1216 ML {* @{sort "{zero,one}"} *}
  1217 ML {* @{typ "'a => 'b"} *}
  1218 ML {* @{term "%x. x"} *}
  1219 ML {* @{prop "x == y"} *}
  1220 ML {* @{ctyp "'a => 'b"} *}
  1221 ML {* @{cterm "%x. x"} *}
  1222 ML {* @{cprop "x == y"} *}
  1223 ML {* @{thm asm_rl} *}
  1224 ML {* @{thms asm_rl} *}
  1225 ML {* @{type_name c} *}
  1226 ML {* @{type_syntax c} *}
  1227 ML {* @{const_name c} *}
  1228 ML {* @{const_syntax c} *}
  1229 ML {* @{context} *}
  1230 ML {* @{theory} *}
  1231 ML {* @{theory Pure} *}
  1232 ML {* @{theory_ref} *}
  1233 ML {* @{theory_ref Pure} *}
  1234 ML {* @{simpset} *}
  1235 ML {* @{claset} *}
  1236 ML {* @{clasimpset} *}
  1237 
  1238 The same works for sources being ``used'' within an Isar context.
  1239 
  1240 * ML in Isar: improved error reporting; extra verbosity with
  1241 ML_Context.trace enabled.
  1242 
  1243 * Pure/General/table.ML: the join operations now works via exceptions
  1244 DUP/SAME instead of type option. This is simpler in simple cases, and
  1245 admits slightly more efficient complex applications.
  1246 
  1247 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1248 use Context.generic instead of just theory.
  1249 
  1250 * Pure: datatype Context.generic joins theory/Proof.context and
  1251 provides some facilities for code that works in either kind of
  1252 context, notably GenericDataFun for uniform theory and proof data.
  1253 
  1254 * Pure: simplified internal attribute type, which is now always
  1255 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1256 local (Proof.context) attributes have been discontinued, while
  1257 minimizing code duplication. Thm.rule_attribute and
  1258 Thm.declaration_attribute build canonical attributes; see also structure
  1259 Context for further operations on Context.generic, notably
  1260 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1261 declarations and definitions.
  1262 
  1263 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1264 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1265 init only required for impure data. INCOMPATIBILITY: empty really need
  1266 to be empty (no dependencies on theory content!)
  1267 
  1268 * Pure/kernel: consts certification ignores sort constraints given in
  1269 signature declarations. (This information is not relevant to the
  1270 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1271 potential INCOMPATIBILITY.
  1272 
  1273 * Pure: axiomatic type classes are now purely definitional, with
  1274 explicit proofs of class axioms and super class relations performed
  1275 internally. See Pure/axclass.ML for the main internal interfaces --
  1276 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1277 AxClass.axiomatize_class/classrel/arity supersede
  1278 Sign.add_classes/classrel/arities.
  1279 
  1280 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1281 global/local versions on theory vs. Proof.context have been
  1282 discontinued; Attrib.syntax and Method.syntax have been adapted
  1283 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1284 attributes, methods, etc.
  1285 
  1286 * Pure: several functions of signature "... -> theory -> theory * ..."
  1287 have been reoriented to "... -> theory -> ... * theory" in order to
  1288 allow natural usage in combination with the ||>, ||>>, |-> and
  1289 fold_map combinators.
  1290 
  1291 * Pure: official theorem names (closed derivations) and additional
  1292 comments (tags) are now strictly separate.  Name hints -- which are
  1293 maintained as tags -- may be attached any time without affecting the
  1294 derivation.
  1295 
  1296 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1297 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1298 achieve the old behaviour.
  1299 
  1300 * Pure: the "Goal" constant is now called "prop", supporting a
  1301 slightly more general idea of ``protecting'' meta-level rule
  1302 statements.
  1303 
  1304 * Pure: Logic.(un)varify only works in a global context, which is now
  1305 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1306 Logic.legacy_(un)varify as temporary workaround.
  1307 
  1308 * Pure: structure Name provides scalable operations for generating
  1309 internal variable names, notably Name.variants etc.  This replaces
  1310 some popular functions from term.ML:
  1311 
  1312   Term.variant		->  Name.variant
  1313   Term.variantlist	->  Name.variant_list
  1314   Term.invent_names	->  Name.invent_list
  1315 
  1316 Note that low-level renaming rarely occurs in new code -- operations
  1317 from structure Variable are used instead (see below).
  1318 
  1319 * Pure: structure Variable provides fundamental operations for proper
  1320 treatment of fixed/schematic variables in a context.  For example,
  1321 Variable.import introduces fixes for schematics of given facts and
  1322 Variable.export reverses the effect (up to renaming) -- this replaces
  1323 various freeze_thaw operations.
  1324 
  1325 * Pure: structure Goal provides simple interfaces for
  1326 init/conclude/finish and tactical prove operations (replacing former
  1327 Tactic.prove).  Goal.prove is the canonical way to prove results
  1328 within a given context; Goal.prove_global is a degraded version for
  1329 theory level goals, including a global Drule.standard.  Note that
  1330 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1331 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1332 in a locale context).
  1333 
  1334 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1335 and type checking (Syntax.check_term etc.), with common combinations
  1336 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1337 which are considered legacy and await removal.
  1338 
  1339 * Pure/Syntax: generic interfaces for type unchecking
  1340 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1341 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1342 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1343 available for convenience, but refer to the very same operations using
  1344 a mere theory instead of a full context.
  1345 
  1346 * Isar: simplified treatment of user-level errors, using exception
  1347 ERROR of string uniformly.  Function error now merely raises ERROR,
  1348 without any side effect on output channels.  The Isar toplevel takes
  1349 care of proper display of ERROR exceptions.  ML code may use plain
  1350 handle/can/try; cat_error may be used to concatenate errors like this:
  1351 
  1352   ... handle ERROR msg => cat_error msg "..."
  1353 
  1354 Toplevel ML code (run directly or through the Isar toplevel) may be
  1355 embedded into the Isar toplevel with exception display/debug like
  1356 this:
  1357 
  1358   Isar.toplevel (fn () => ...)
  1359 
  1360 INCOMPATIBILITY, removed special transform_error facilities, removed
  1361 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1362 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1363 -- use plain ERROR instead.
  1364 
  1365 * Isar: theory setup now has type (theory -> theory), instead of a
  1366 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1367 
  1368 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1369 ProofContext.debug/verbose flags.
  1370 
  1371 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1372 theory before entering a proof state.  Transactions now always see a
  1373 quasi-functional intermediate checkpoint, both in interactive and
  1374 batch mode.
  1375 
  1376 * Isar: simplified interfaces for outer syntax.  Renamed
  1377 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1378 OuterSyntax.add_parsers -- this functionality is now included in
  1379 OuterSyntax.command etc.  INCOMPATIBILITY.
  1380 
  1381 * Simplifier: the simpset of a running simplification process now
  1382 contains a proof context (cf. Simplifier.the_context), which is the
  1383 very context that the initial simpset has been retrieved from (by
  1384 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1385 (solver, looper etc.) may depend on arbitrary proof data.
  1386 
  1387 * Simplifier.inherit_context inherits the proof context (plus the
  1388 local bounds) of the current simplification process; any simproc
  1389 etc. that calls the Simplifier recursively should do this!  Removed
  1390 former Simplifier.inherit_bounds, which is already included here --
  1391 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1392 specify an explicit context using Simplifier.context/theory_context.
  1393 
  1394 * Simplifier/Classical Reasoner: more abstract interfaces
  1395 change_simpset/claset for modifying the simpset/claset reference of a
  1396 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1397 INCOMPATIBILITY.
  1398 
  1399 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1400 "Trueprop" etc.
  1401 
  1402 
  1403 *** System ***
  1404 
  1405 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1406 locations -- now includes the Isabelle version identifier as well.
  1407 This simplifies use of multiple Isabelle installations.
  1408 
  1409 * isabelle-process: option -S (secure mode) disables some critical
  1410 operations, notably runtime compilation and evaluation of ML source
  1411 code.
  1412 
  1413 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1414 
  1415 * Support for parallel execution, using native multicore support of
  1416 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1417 independent theories, according to the given theory header
  1418 specifications. The maximum number of worker threads is specified via
  1419 usedir option -M or the "max-threads" setting in Proof General. A
  1420 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1421 to 6 on a 8-core machine.  User-code needs to observe certain
  1422 guidelines for thread-safe programming, see appendix A in the Isar
  1423 Implementation manual.
  1424 
  1425 
  1426 New in Isabelle2005 (October 2005)
  1427 ----------------------------------
  1428 
  1429 *** General ***
  1430 
  1431 * Theory headers: the new header syntax for Isar theories is
  1432 
  1433   theory <name>
  1434   imports <theory1> ... <theoryN>
  1435   uses <file1> ... <fileM>
  1436   begin
  1437 
  1438 where the 'uses' part is optional.  The previous syntax
  1439 
  1440   theory <name> = <theory1> + ... + <theoryN>:
  1441 
  1442 will disappear in the next release.  Use isatool fixheaders to convert
  1443 existing theory files.  Note that there is no change in ancient
  1444 non-Isar theories now, but these will disappear soon.
  1445 
  1446 * Theory loader: parent theories can now also be referred to via
  1447 relative and absolute paths.
  1448 
  1449 * Command 'find_theorems' searches for a list of criteria instead of a
  1450 list of constants. Known criteria are: intro, elim, dest, name:string,
  1451 simp:term, and any term. Criteria can be preceded by '-' to select
  1452 theorems that do not match. Intro, elim, dest select theorems that
  1453 match the current goal, name:s selects theorems whose fully qualified
  1454 name contain s, and simp:term selects all simplification rules whose
  1455 lhs match term.  Any other term is interpreted as pattern and selects
  1456 all theorems matching the pattern. Available in ProofGeneral under
  1457 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1458 
  1459   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1460 
  1461 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1462 matching the current goal as introduction rule and not having "HOL."
  1463 in their name (i.e. not being defined in theory HOL).
  1464 
  1465 * Command 'thms_containing' has been discontinued in favour of
  1466 'find_theorems'; INCOMPATIBILITY.
  1467 
  1468 * Communication with Proof General is now 8bit clean, which means that
  1469 Unicode text in UTF-8 encoding may be used within theory texts (both
  1470 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1471 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1472 
  1473   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1474   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1475 
  1476 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1477 Classical Reasoner.  Typical big applications run around 2 times
  1478 faster.
  1479 
  1480 
  1481 *** Document preparation ***
  1482 
  1483 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1484 of raw sources.  Only those symbols that do not require additional
  1485 LaTeX packages (depending on comments in isabellesym.sty) are
  1486 displayed properly, everything else is left verbatim.  isatool display
  1487 and isatool print are used as front ends (these are subject to the
  1488 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1489 
  1490 * Command tags control specific markup of certain regions of text,
  1491 notably folding and hiding.  Predefined tags include "theory" (for
  1492 theory begin and end), "proof" for proof commands, and "ML" for
  1493 commands involving ML code; the additional tags "visible" and
  1494 "invisible" are unused by default.  Users may give explicit tag
  1495 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1496 interpretation of tags is determined by the LaTeX job during document
  1497 preparation: see option -V of isatool usedir, or options -n and -t of
  1498 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1499 \isadroptag.
  1500 
  1501 Several document versions may be produced at the same time via isatool
  1502 usedir (the generated index.html will link all of them).  Typical
  1503 specifications include ''-V document=theory,proof,ML'' to present
  1504 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1505 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1506 these parts without any formal replacement text.  The Isabelle site
  1507 default settings produce ''document'' and ''outline'' versions as
  1508 specified above.
  1509 
  1510 * Several new antiquotations:
  1511 
  1512   @{term_type term} prints a term with its type annotated;
  1513 
  1514   @{typeof term} prints the type of a term;
  1515 
  1516   @{const const} is the same as @{term const}, but checks that the
  1517   argument is a known logical constant;
  1518 
  1519   @{term_style style term} and @{thm_style style thm} print a term or
  1520   theorem applying a "style" to it
  1521 
  1522   @{ML text}
  1523 
  1524 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1525 definitions, equations, inequations etc., 'concl' printing only the
  1526 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1527 to print the specified premise.  TermStyle.add_style provides an ML
  1528 interface for introducing further styles.  See also the "LaTeX Sugar"
  1529 document practical applications.  The ML antiquotation prints
  1530 type-checked ML expressions verbatim.
  1531 
  1532 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1533 and 'text' support optional locale specification '(in loc)', which
  1534 specifies the default context for interpreting antiquotations.  For
  1535 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1536 
  1537 * Option 'locale=NAME' of antiquotations specifies an alternative
  1538 context interpreting the subsequent argument.  For example: @{thm
  1539 [locale=lattice] inf_assoc}.
  1540 
  1541 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1542 a proof context.
  1543 
  1544 * Proper output of antiquotations for theory commands involving a
  1545 proof context (such as 'locale' or 'theorem (in loc) ...').
  1546 
  1547 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1548 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1549 
  1550 * isatool usedir: new option -C (default true) controls whether option
  1551 -D should include a copy of the original document directory; -C false
  1552 prevents unwanted effects such as copying of administrative CVS data.
  1553 
  1554 
  1555 *** Pure ***
  1556 
  1557 * Considerably improved version of 'constdefs' command.  Now performs
  1558 automatic type-inference of declared constants; additional support for
  1559 local structure declarations (cf. locales and HOL records), see also
  1560 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1561 sequential dependencies of definitions within a single 'constdefs'
  1562 section; moreover, the declared name needs to be an identifier.  If
  1563 all fails, consider to fall back on 'consts' and 'defs' separately.
  1564 
  1565 * Improved indexed syntax and implicit structures.  First of all,
  1566 indexed syntax provides a notational device for subscripted
  1567 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1568 expressions.  Secondly, in a local context with structure
  1569 declarations, number indexes \<^sub>n or the empty index (default
  1570 number 1) refer to a certain fixed variable implicitly; option
  1571 show_structs controls printing of implicit structures.  Typical
  1572 applications of these concepts involve record types and locales.
  1573 
  1574 * New command 'no_syntax' removes grammar declarations (and
  1575 translations) resulting from the given syntax specification, which is
  1576 interpreted in the same manner as for the 'syntax' command.
  1577 
  1578 * 'Advanced' translation functions (parse_translation etc.) may depend
  1579 on the signature of the theory context being presently used for
  1580 parsing/printing, see also isar-ref manual.
  1581 
  1582 * Improved 'oracle' command provides a type-safe interface to turn an
  1583 ML expression of type theory -> T -> term into a primitive rule of
  1584 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1585 is already included here); see also FOL/ex/IffExample.thy;
  1586 INCOMPATIBILITY.
  1587 
  1588 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1589 before); "cI" is no longer bound, use "c.intro" instead.
  1590 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1591 axclasses vs. locales.
  1592 
  1593 * Improved internal renaming of symbolic identifiers -- attach primes
  1594 instead of base 26 numbers.
  1595 
  1596 * New flag show_question_marks controls printing of leading question
  1597 marks in schematic variable names.
  1598 
  1599 * In schematic variable names, *any* symbol following \<^isub> or
  1600 \<^isup> is now treated as part of the base name.  For example, the
  1601 following works without printing of awkward ".0" indexes:
  1602 
  1603   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1604     by simp
  1605 
  1606 * Inner syntax includes (*(*nested*) comments*).
  1607 
  1608 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1609 annotations as "(00...)".
  1610 
  1611 * Clear separation of logical types and nonterminals, where the latter
  1612 may only occur in 'syntax' specifications or type abbreviations.
  1613 Before that distinction was only partially implemented via type class
  1614 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1615 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1616 exotic syntax specifications may require further adaption
  1617 (e.g. Cube/Cube.thy).
  1618 
  1619 * Removed obsolete type class "logic", use the top sort {} instead.
  1620 Note that non-logical types should be declared as 'nonterminals'
  1621 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1622 specifications.
  1623 
  1624 * Attributes 'induct' and 'cases': type or set names may now be
  1625 locally fixed variables as well.
  1626 
  1627 * Simplifier: can now control the depth to which conditional rewriting
  1628 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1629 Limit.
  1630 
  1631 * Simplifier: simplification procedures may now take the current
  1632 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1633 interface), which is very useful for calling the Simplifier
  1634 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1635 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1636 low-level mk_simproc no longer applies Logic.varify internally, to
  1637 allow for use in a context of fixed variables.
  1638 
  1639 * thin_tac now works even if the assumption being deleted contains !!
  1640 or ==>.  More generally, erule now works even if the major premise of
  1641 the elimination rule contains !! or ==>.
  1642 
  1643 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1644 
  1645 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1646 from Pure, which contains all common declarations already.  Both
  1647 theories are defined via plain Isabelle/Isar .thy files.
  1648 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1649 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1650 use isatool fixcpure to adapt your theory and ML sources.
  1651 
  1652 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1653 selections of theorems in named facts via index ranges.
  1654 
  1655 * 'print_theorems': in theory mode, really print the difference
  1656 wrt. the last state (works for interactive theory development only),
  1657 in proof mode print all local facts (cf. 'print_facts');
  1658 
  1659 * 'hide': option '(open)' hides only base names.
  1660 
  1661 * More efficient treatment of intermediate checkpoints in interactive
  1662 theory development.
  1663 
  1664 * Code generator is now invoked via code_module (incremental code
  1665 generation) and code_library (modular code generation, ML structures
  1666 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1667 must be quoted when used as identifiers.
  1668 
  1669 * New 'value' command for reading, evaluating and printing terms using
  1670 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1671 quoted when used as identifier.
  1672 
  1673 
  1674 *** Locales ***
  1675 
  1676 * New commands for the interpretation of locale expressions in
  1677 theories (1), locales (2) and proof contexts (3).  These generate
  1678 proof obligations from the expression specification.  After the
  1679 obligations have been discharged, theorems of the expression are added
  1680 to the theory, target locale or proof context.  The synopsis of the
  1681 commands is a follows:
  1682 
  1683   (1) interpretation expr inst
  1684   (2) interpretation target < expr
  1685   (3) interpret expr inst
  1686 
  1687 Interpretation in theories and proof contexts require a parameter
  1688 instantiation of terms from the current context.  This is applied to
  1689 specifications and theorems of the interpreted expression.
  1690 Interpretation in locales only permits parameter renaming through the
  1691 locale expression.  Interpretation is smart in that interpretations
  1692 that are active already do not occur in proof obligations, neither are
  1693 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1694 inspect active interpretations of a particular locale.  For details,
  1695 see the Isar Reference manual.  Examples can be found in
  1696 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1697 
  1698 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1699 'interpret' instead.
  1700 
  1701 * New context element 'constrains' for adding type constraints to
  1702 parameters.
  1703 
  1704 * Context expressions: renaming of parameters with syntax
  1705 redeclaration.
  1706 
  1707 * Locale declaration: 'includes' disallowed.
  1708 
  1709 * Proper static binding of attribute syntax -- i.e. types / terms /
  1710 facts mentioned as arguments are always those of the locale definition
  1711 context, independently of the context of later invocations.  Moreover,
  1712 locale operations (renaming and type / term instantiation) are applied
  1713 to attribute arguments as expected.
  1714 
  1715 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1716 actual attributes; rare situations may require Attrib.attribute to
  1717 embed those attributes into Attrib.src that lack concrete syntax.
  1718 Attribute implementations need to cooperate properly with the static
  1719 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1720 Attrib.XXX_thm etc. already do the right thing without further
  1721 intervention.  Only unusual applications -- such as "where" or "of"
  1722 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1723 on the context and the facts involved -- may have to assign parsed
  1724 values to argument tokens explicitly.
  1725 
  1726 * Changed parameter management in theorem generation for long goal
  1727 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1728 theorem statement in rare situations.
  1729 
  1730 * Locale inspection command 'print_locale' omits notes elements.  Use
  1731 'print_locale!' to have them included in the output.
  1732 
  1733 
  1734 *** Provers ***
  1735 
  1736 * Provers/hypsubst.ML: improved version of the subst method, for
  1737 single-step rewriting: it now works in bound variable contexts. New is
  1738 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1739 rewrite a different subterm than the original subst method, which is
  1740 still available as 'simplesubst'.
  1741 
  1742 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1743 and quasi orders.
  1744 
  1745 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1746 reflexive-transitive closure of relations.
  1747 
  1748 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1749 limit (previously hard-coded with a value of 20) user-definable.
  1750 
  1751 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1752 is peformed already.  Object-logics merely need to finish their
  1753 initial simpset configuration as before.  INCOMPATIBILITY.
  1754 
  1755 
  1756 *** HOL ***
  1757 
  1758 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1759 
  1760   syntax (epsilon)
  1761     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1762 
  1763 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1764 and x-symbol; use option '-m epsilon' to get it actually printed.
  1765 Moreover, the mathematically important symbolic identifier \<epsilon>
  1766 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1767 
  1768 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1769 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1770 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1771 support corresponding Isar calculations.
  1772 
  1773 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1774 instead of ":".
  1775 
  1776 * theory SetInterval: changed the syntax for open intervals:
  1777 
  1778   Old       New
  1779   {..n(}    {..<n}
  1780   {)n..}    {n<..}
  1781   {m..n(}   {m..<n}
  1782   {)m..n}   {m<..n}
  1783   {)m..n(}  {m<..<n}
  1784 
  1785 The old syntax is still supported but will disappear in the next
  1786 release.  For conversion use the following Emacs search and replace
  1787 patterns (these are not perfect but work quite well):
  1788 
  1789   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1790   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1791 
  1792 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1793 equalities in commutative rings; method 'algebra' provides a generic
  1794 interface.
  1795 
  1796 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1797 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1798 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1799 be a tuple pattern.
  1800 
  1801 Some new syntax forms are available:
  1802 
  1803   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1804   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1805   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1806   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1807 
  1808 The latter form "\<Sum>x < k. e" used to be based on a separate
  1809 function "Summation", which has been discontinued.
  1810 
  1811 * theory Finite_Set: in structured induction proofs, the insert case
  1812 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1813 (insert F x)'.
  1814 
  1815 * The 'refute' command has been extended to support a much larger
  1816 fragment of HOL, including axiomatic type classes, constdefs and
  1817 typedefs, inductive datatypes and recursion.
  1818 
  1819 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1820 Requires zChaff with proof generation to be installed.  See
  1821 HOL/ex/SAT_Examples.thy for examples.
  1822 
  1823 * Datatype induction via method 'induct' now preserves the name of the
  1824 induction variable. For example, when proving P(xs::'a list) by
  1825 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1826 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1827 in unstructured proof scripts.
  1828 
  1829 * Reworked implementation of records.  Improved scalability for
  1830 records with many fields, avoiding performance problems for type
  1831 inference. Records are no longer composed of nested field types, but
  1832 of nested extension types. Therefore the record type only grows linear
  1833 in the number of extensions and not in the number of fields.  The
  1834 top-level (users) view on records is preserved.  Potential
  1835 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1836 old record representation. The type generated for a record is called
  1837 <record_name>_ext_type.
  1838 
  1839 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1840 proofs triggered by a record definition or a simproc (if
  1841 quick_and_dirty is enabled).  Definitions of large records can take
  1842 quite long.
  1843 
  1844 New simproc record_upd_simproc for simplification of multiple record
  1845 updates enabled by default.  Moreover, trivial updates are also
  1846 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1847 occasionally, since simplification is more powerful by default.
  1848 
  1849 * typedef: proper support for polymorphic sets, which contain extra
  1850 type-variables in the term.
  1851 
  1852 * Simplifier: automatically reasons about transitivity chains
  1853 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1854 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1855 old proofs break occasionally as simplification may now solve more
  1856 goals than previously.
  1857 
  1858 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1859 present.  Works for all partial orders (class "order"), in particular
  1860 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1861 just like y <= x.
  1862 
  1863 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1864 bound variable or a constant then the let is unfolded.  Otherwise
  1865 first a is simplified to b, and then f b is simplified to g. If
  1866 possible we abstract b from g arriving at "let x = b in h x",
  1867 otherwise we unfold the let and arrive at g.  The simproc can be
  1868 enabled/disabled by the reference use_let_simproc.  Potential
  1869 INCOMPATIBILITY since simplification is more powerful by default.
  1870 
  1871 * Classical reasoning: the meson method now accepts theorems as arguments.
  1872 
  1873 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1874 jobs to provide advice on the provability of subgoals.
  1875 
  1876 * Theory OrderedGroup and Ring_and_Field: various additions and
  1877 improvements to faciliate calculations involving equalities and
  1878 inequalities.
  1879 
  1880 The following theorems have been eliminated or modified
  1881 (INCOMPATIBILITY):
  1882 
  1883   abs_eq             now named abs_of_nonneg
  1884   abs_of_ge_0        now named abs_of_nonneg
  1885   abs_minus_eq       now named abs_of_nonpos
  1886   imp_abs_id         now named abs_of_nonneg
  1887   imp_abs_neg_id     now named abs_of_nonpos
  1888   mult_pos           now named mult_pos_pos
  1889   mult_pos_le        now named mult_nonneg_nonneg
  1890   mult_pos_neg_le    now named mult_nonneg_nonpos
  1891   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1892   mult_neg           now named mult_neg_neg
  1893   mult_neg_le        now named mult_nonpos_nonpos
  1894 
  1895 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1896      
  1897      zero_le_square
  1898      not_square_less_zero 
  1899 
  1900   The following lemmas have been deleted from Real/RealPow:
  1901   
  1902      realpow_zero_zero
  1903      realpow_two
  1904      realpow_less
  1905      zero_le_power
  1906      realpow_two_le
  1907      abs_realpow_two
  1908      realpow_two_abs     
  1909 
  1910 * Theory Parity: added rules for simplifying exponents.
  1911 
  1912 * Theory List:
  1913 
  1914 The following theorems have been eliminated or modified
  1915 (INCOMPATIBILITY):
  1916 
  1917   list_all_Nil       now named list_all.simps(1)
  1918   list_all_Cons      now named list_all.simps(2)
  1919   list_all_conv      now named list_all_iff
  1920   set_mem_eq         now named mem_iff
  1921 
  1922 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1923 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1924 
  1925 
  1926 *** HOL-Complex ***
  1927 
  1928 * Theory RealDef: better support for embedding natural numbers and
  1929 integers in the reals.
  1930 
  1931 The following theorems have been eliminated or modified
  1932 (INCOMPATIBILITY):
  1933 
  1934   exp_ge_add_one_self  now requires no hypotheses
  1935   real_of_int_add      reversed direction of equality (use [symmetric])
  1936   real_of_int_minus    reversed direction of equality (use [symmetric])
  1937   real_of_int_diff     reversed direction of equality (use [symmetric])
  1938   real_of_int_mult     reversed direction of equality (use [symmetric])
  1939 
  1940 * Theory RComplete: expanded support for floor and ceiling functions.
  1941 
  1942 * Theory Ln is new, with properties of the natural logarithm
  1943 
  1944 * Hyperreal: There is a new type constructor "star" for making
  1945 nonstandard types.  The old type names are now type synonyms:
  1946 
  1947   hypreal = real star
  1948   hypnat = nat star
  1949   hcomplex = complex star
  1950 
  1951 * Hyperreal: Many groups of similarly-defined constants have been
  1952 replaced by polymorphic versions (INCOMPATIBILITY):
  1953 
  1954   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1955 
  1956   starset      <-- starsetNat, starsetC
  1957   *s*          <-- *sNat*, *sc*
  1958   starset_n    <-- starsetNat_n, starsetC_n
  1959   *sn*         <-- *sNatn*, *scn*
  1960   InternalSets <-- InternalNatSets, InternalCSets
  1961 
  1962   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1963   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1964   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1965   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1966   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1967 
  1968 * Hyperreal: Many type-specific theorems have been removed in favor of
  1969 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1970 
  1971   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1972   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1973   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1974   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1975   right_minus <-- hypreal_add_minus
  1976   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1977   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1978   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1979   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1980   mult_1_right <-- hcomplex_mult_one_right
  1981   mult_zero_left <-- hcomplex_mult_zero_left
  1982   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1983   right_distrib <-- hypnat_add_mult_distrib2
  1984   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1985   right_inverse <-- hypreal_mult_inverse
  1986   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1987   order_refl <-- {hypreal,hypnat}_le_refl
  1988   order_trans <-- {hypreal,hypnat}_le_trans
  1989   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1990   order_less_le <-- {hypreal,hypnat}_less_le
  1991   linorder_linear <-- {hypreal,hypnat}_le_linear
  1992   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1993   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1994   add_nonneg_nonneg <-- hypreal_le_add_order
  1995 
  1996 * Hyperreal: Separate theorems having to do with type-specific
  1997 versions of constants have been merged into theorems that apply to the
  1998 new polymorphic constants (INCOMPATIBILITY):
  1999 
  2000   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2001   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2002   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2003   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2004   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2005   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2006   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2007   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2008   STAR_diff <-- {STAR,STARC}_diff
  2009   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2010     STARC_hcomplex_of_complex}_image_subset
  2011   starset_n_Un <-- starset{Nat,C}_n_Un
  2012   starset_n_Int <-- starset{Nat,C}_n_Int
  2013   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2014   starset_n_diff <-- starset{Nat,C}_n_diff
  2015   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2016   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2017   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2018   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2019   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2020   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2021   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2022   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2023   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2024   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2025   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2026   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2027   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2028   starfun_diff <-- starfun{C,RC,CR}_diff
  2029   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2030   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2031   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2032   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2033   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2034   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2035   starfun_Id <-- starfunC_Id
  2036   starfun_approx <-- starfun{Nat,CR}_approx
  2037   starfun_capprox <-- starfun{C,RC}_capprox
  2038   starfun_abs <-- starfunNat_rabs
  2039   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2040   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2041   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2042   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2043   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2044   starfun_add_approx <-- starfunCR_add_approx
  2045   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2046   starfun_divide <-- starfun{C,CR,RC}_divide
  2047   starfun_n <-- starfun{Nat,C}_n
  2048   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2049   starfun_n_add <-- starfun{Nat,C}_n_add
  2050   starfun_n_add_minus <-- starfunNat_n_add_minus
  2051   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2052   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2053   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2054 
  2055   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2056   star_n_minus <-- {hypreal,hcomplex}_minus
  2057   star_n_diff <-- {hypreal,hcomplex}_diff
  2058   star_n_mult <-- {hypreal,hcomplex}_mult
  2059   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2060   star_n_le <-- {hypreal,hypnat}_le
  2061   star_n_less <-- {hypreal,hypnat}_less
  2062   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2063   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2064   star_n_abs <-- hypreal_hrabs
  2065   star_n_divide <-- hcomplex_divide
  2066 
  2067   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2068   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2069   star_of_diff <-- hypreal_of_real_diff
  2070   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2071   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2072   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2073   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2074   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2075   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2076   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2077   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2078   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2079   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2080   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2081   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2082   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2083   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2084   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2085   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2086   star_of_power <-- hypreal_of_real_power
  2087   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2088 
  2089 * Hyperreal: new method "transfer" that implements the transfer
  2090 principle of nonstandard analysis. With a subgoal that mentions
  2091 nonstandard types like "'a star", the command "apply transfer"
  2092 replaces it with an equivalent one that mentions only standard types.
  2093 To be successful, all free variables must have standard types; non-
  2094 standard variables must have explicit universal quantifiers.
  2095 
  2096 * Hyperreal: A theory of Taylor series.
  2097 
  2098 
  2099 *** HOLCF ***
  2100 
  2101 * Discontinued special version of 'constdefs' (which used to support
  2102 continuous functions) in favor of the general Pure one with full
  2103 type-inference.
  2104 
  2105 * New simplification procedure for solving continuity conditions; it
  2106 is much faster on terms with many nested lambda abstractions (cubic
  2107 instead of exponential time).
  2108 
  2109 * New syntax for domain package: selector names are now optional.
  2110 Parentheses should be omitted unless argument is lazy, for example:
  2111 
  2112   domain 'a stream = cons "'a" (lazy "'a stream")
  2113 
  2114 * New command 'fixrec' for defining recursive functions with pattern
  2115 matching; defining multiple functions with mutual recursion is also
  2116 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2117 sinr, or any data constructor defined by the domain package. The given
  2118 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2119 syntax and examples.
  2120 
  2121 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2122 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2123 but the proof obligation additionally includes an admissibility
  2124 requirement. The packages generate instances of class cpo or pcpo,
  2125 with continuity and strictness theorems for Rep and Abs.
  2126 
  2127 * HOLCF: Many theorems have been renamed according to a more standard naming
  2128 scheme (INCOMPATIBILITY):
  2129 
  2130   foo_inject:  "foo$x = foo$y ==> x = y"
  2131   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2132   foo_less:    "(foo$x << foo$y) = (x << y)"
  2133   foo_strict:  "foo$UU = UU"
  2134   foo_defined: "... ==> foo$x ~= UU"
  2135   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2136 
  2137 
  2138 *** ZF ***
  2139 
  2140 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2141 including the First Isomorphism Theorem (on quotienting by the kernel
  2142 of a homomorphism).
  2143 
  2144 * ZF/Simplifier: install second copy of type solver that actually
  2145 makes use of TC rules declared to Isar proof contexts (or locales);
  2146 the old version is still required for ML proof scripts.
  2147 
  2148 
  2149 *** Cube ***
  2150 
  2151 * Converted to Isar theory format; use locales instead of axiomatic
  2152 theories.
  2153 
  2154 
  2155 *** ML ***
  2156 
  2157 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2158 for ||>, ||>>, |>>,
  2159 
  2160 * Pure/library.ML no longer defines its own option datatype, but uses
  2161 that of the SML basis, which has constructors NONE and SOME instead of
  2162 None and Some, as well as exception Option.Option instead of OPTION.
  2163 The functions the, if_none, is_some, is_none have been adapted
  2164 accordingly, while Option.map replaces apsome.
  2165 
  2166 * Pure/library.ML: the exception LIST has been given up in favour of
  2167 the standard exceptions Empty and Subscript, as well as
  2168 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2169 superceded by the standard hd and tl functions etc.
  2170 
  2171 A number of basic list functions are no longer exported to the ML
  2172 toplevel, as they are variants of predefined functions.  The following
  2173 suggests how one can translate existing code:
  2174 
  2175     rev_append xs ys = List.revAppend (xs, ys)
  2176     nth_elem (i, xs) = List.nth (xs, i)
  2177     last_elem xs = List.last xs
  2178     flat xss = List.concat xss
  2179     seq fs = List.app fs
  2180     partition P xs = List.partition P xs
  2181     mapfilter f xs = List.mapPartial f xs
  2182 
  2183 * Pure/library.ML: several combinators for linear functional
  2184 transformations, notably reverse application and composition:
  2185 
  2186   x |> f                f #> g
  2187   (x, y) |-> f          f #-> g
  2188 
  2189 * Pure/library.ML: introduced/changed precedence of infix operators:
  2190 
  2191   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2192   infix 2 ?;
  2193   infix 3 o oo ooo oooo;
  2194   infix 4 ~~ upto downto;
  2195 
  2196 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2197 infix operators.
  2198 
  2199 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2200 fold_map support linear functional transformations and nesting.  For
  2201 example:
  2202 
  2203   fold f [x1, ..., xN] y =
  2204     y |> f x1 |> ... |> f xN
  2205 
  2206   (fold o fold) f [xs1, ..., xsN] y =
  2207     y |> fold f xs1 |> ... |> fold f xsN
  2208 
  2209   fold f [x1, ..., xN] =
  2210     f x1 #> ... #> f xN
  2211 
  2212   (fold o fold) f [xs1, ..., xsN] =
  2213     fold f xs1 #> ... #> fold f xsN
  2214 
  2215 * Pure/library.ML: the following selectors on type 'a option are
  2216 available:
  2217 
  2218   the:               'a option -> 'a  (*partial*)
  2219   these:             'a option -> 'a  where 'a = 'b list
  2220   the_default: 'a -> 'a option -> 'a
  2221   the_list:          'a option -> 'a list
  2222 
  2223 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2224 basic operations for association lists, following natural argument
  2225 order; moreover the explicit equality predicate passed here avoids
  2226 potentially expensive polymorphic runtime equality checks.
  2227 The old functions may be expressed as follows:
  2228 
  2229   assoc = uncurry (AList.lookup (op =))
  2230   assocs = these oo AList.lookup (op =)
  2231   overwrite = uncurry (AList.update (op =)) o swap
  2232 
  2233 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2234 
  2235   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2236   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2237 
  2238 replacing make_keylist and keyfilter (occassionally used)
  2239 Naive rewrites:
  2240 
  2241   make_keylist = AList.make
  2242   keyfilter = AList.find (op =)
  2243 
  2244 * eq_fst and eq_snd now take explicit equality parameter, thus
  2245   avoiding eqtypes. Naive rewrites:
  2246 
  2247     eq_fst = eq_fst (op =)
  2248     eq_snd = eq_snd (op =)
  2249 
  2250 * Removed deprecated apl and apr (rarely used).
  2251   Naive rewrites:
  2252 
  2253     apl (n, op) =>>= curry op n
  2254     apr (op, m) =>>= fn n => op (n, m)
  2255 
  2256 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2257 provides a reasonably efficient light-weight implementation of sets as
  2258 lists.
  2259 
  2260 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2261 few new operations; existing lookup and update are now curried to
  2262 follow natural argument order (for use with fold etc.);
  2263 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2264 
  2265 * Pure/General: output via the Isabelle channels of
  2266 writeln/warning/error etc. is now passed through Output.output, with a
  2267 hook for arbitrary transformations depending on the print_mode
  2268 (cf. Output.add_mode -- the first active mode that provides a output
  2269 function wins).  Already formatted output may be embedded into further
  2270 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2271 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2272 accommodate easy composition of diagnostic messages etc.  Programmers
  2273 rarely need to care about Output.output or Output.raw at all, with
  2274 some notable exceptions: Output.output is required when bypassing the
  2275 standard channels (writeln etc.), or in token translations to produce
  2276 properly formatted results; Output.raw is required when capturing
  2277 already output material that will eventually be presented to the user
  2278 a second time.  For the default print mode, both Output.output and
  2279 Output.raw have no effect.
  2280 
  2281 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2282 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2283 cumulative results are displayed at the end of a batch session.
  2284 
  2285 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2286 replaced by File.platform_path and File.shell_path (with appropriate
  2287 hooks).  This provides a clean interface for unusual systems where the
  2288 internal and external process view of file names are different.
  2289 
  2290 * Pure: more efficient orders for basic syntactic entities: added
  2291 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2292 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2293 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2294 orders now -- potential INCOMPATIBILITY for code that depends on a
  2295 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2296 Library.sort_strings on result).
  2297 
  2298 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2299 fold_types traverse types/terms from left to right, observing natural
  2300 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2301 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2302 
  2303 * Pure: name spaces have been refined, with significant changes of the
  2304 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2305 to extern(_table).  The plain name entry path is superceded by a
  2306 general 'naming' context, which also includes the 'policy' to produce
  2307 a fully qualified name and external accesses of a fully qualified
  2308 name; NameSpace.extend is superceded by context dependent
  2309 Sign.declare_name.  Several theory and proof context operations modify
  2310 the naming context.  Especially note Theory.restore_naming and
  2311 ProofContext.restore_naming to get back to a sane state; note that
  2312 Theory.add_path is no longer sufficient to recover from
  2313 Theory.absolute_path in particular.
  2314 
  2315 * Pure: new flags short_names (default false) and unique_names
  2316 (default true) for controlling output of qualified names.  If
  2317 short_names is set, names are printed unqualified.  If unique_names is
  2318 reset, the name prefix is reduced to the minimum required to achieve
  2319 the original result when interning again, even if there is an overlap
  2320 with earlier declarations.
  2321 
  2322 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2323 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2324 (useful for printing error messages).  INCOMPATIBILITY.
  2325 
  2326 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2327 Theory.theory are now identified, referring to the universal
  2328 Context.theory (see Pure/context.ML).  Actual signature and theory
  2329 content is managed as theory data.  The old code and interfaces were
  2330 spread over many files and structures; the new arrangement introduces
  2331 considerable INCOMPATIBILITY to gain more clarity:
  2332 
  2333   Context -- theory management operations (name, identity, inclusion,
  2334     parents, ancestors, merge, etc.), plus generic theory data;
  2335 
  2336   Sign -- logical signature and syntax operations (declaring consts,
  2337     types, etc.), plus certify/read for common entities;
  2338 
  2339   Theory -- logical theory operations (stating axioms, definitions,
  2340     oracles), plus a copy of logical signature operations (consts,
  2341     types, etc.); also a few basic management operations (Theory.copy,
  2342     Theory.merge, etc.)
  2343 
  2344 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2345 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2346 for convenience -- they merely return the theory.
  2347 
  2348 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2349 
  2350 * Pure: the Isar proof context type is already defined early in Pure
  2351 as Context.proof (note that ProofContext.context and Proof.context are
  2352 aliases, where the latter is the preferred name).  This enables other
  2353 Isabelle components to refer to that type even before Isar is present.
  2354 
  2355 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2356 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2357 any of these kinds.  For example, Sign.intern typeK is now
  2358 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2359 Theory.hide_types.  Also note that former
  2360 Theory.hide_classes/types/consts are now
  2361 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2362 internalize their arguments!  INCOMPATIBILITY.
  2363 
  2364 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2365 datatype thmref (with constructors Name and NameSelection) instead of
  2366 plain string -- INCOMPATIBILITY;
  2367 
  2368 * Pure: cases produced by proof methods specify options, where NONE
  2369 means to remove case bindings -- INCOMPATIBILITY in
  2370 (RAW_)METHOD_CASES.
  2371 
  2372 * Pure: the following operations retrieve axioms or theorems from a
  2373 theory node or theory hierarchy, respectively:
  2374 
  2375   Theory.axioms_of: theory -> (string * term) list
  2376   Theory.all_axioms_of: theory -> (string * term) list
  2377   PureThy.thms_of: theory -> (string * thm) list
  2378   PureThy.all_thms_of: theory -> (string * thm) list
  2379 
  2380 * Pure: print_tac now outputs the goal through the trace channel.
  2381 
  2382 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2383 Reference Toplevel.debug (default false) controls detailed printing
  2384 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2385 controls execution profiling -- set to 1 for time and 2 for space
  2386 (both increase the runtime).
  2387 
  2388 * Isar session: The initial use of ROOT.ML is now always timed,
  2389 i.e. the log will show the actual process times, in contrast to the
  2390 elapsed wall-clock time that the outer shell wrapper produces.
  2391 
  2392 * Simplifier: improved handling of bound variables (nameless
  2393 representation, avoid allocating new strings).  Simprocs that invoke
  2394 the Simplifier recursively should use Simplifier.inherit_bounds to
  2395 avoid local name clashes.  Failure to do so produces warnings
  2396 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2397 for further details.
  2398 
  2399 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2400 bindings for all theorems stored within a given theory; this may help
  2401 in porting non-Isar theories to Isar ones, while keeping ML proof
  2402 scripts for the time being.
  2403 
  2404 * ML operator HTML.with_charset specifies the charset begin used for
  2405 generated HTML files.  For example:
  2406 
  2407   HTML.with_charset "utf-8" use_thy "Hebrew";
  2408   HTML.with_charset "utf-8" use_thy "Chinese";
  2409 
  2410 
  2411 *** System ***
  2412 
  2413 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2414 isabelle, isatool etc.).
  2415 
  2416 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2417 isatool doc, isatool mkdir, display_drafts etc.).
  2418 
  2419 * isatool usedir: option -f allows specification of the ML file to be
  2420 used by Isabelle; default is ROOT.ML.
  2421 
  2422 * New isatool version outputs the version identifier of the Isabelle
  2423 distribution being used.
  2424 
  2425 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2426 (containing Boolean satisfiability problems) into Isabelle/HOL
  2427 theories.
  2428 
  2429 
  2430 
  2431 New in Isabelle2004 (April 2004)
  2432 --------------------------------
  2433 
  2434 *** General ***
  2435 
  2436 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2437   Replaces linorder.ML.
  2438 
  2439 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2440   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2441   (\<a>...\<z>), are now considered normal letters, and can therefore
  2442   be used anywhere where an ASCII letter (a...zA...Z) has until
  2443   now. COMPATIBILITY: This obviously changes the parsing of some
  2444   terms, especially where a symbol has been used as a binder, say
  2445   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2446   as an identifier.  Fix it by inserting a space around former
  2447   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2448   existing theory and ML files.
  2449 
  2450 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2451 
  2452 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2453   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2454   a normal (but invisible) letter. For multiple letter subscripts repeat
  2455   \<^isub> like this: x\<^isub>1\<^isub>2.
  2456 
  2457 * Pure: There are now sub-/superscripts that can span more than one
  2458   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2459   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2460   superscript. The new control characters are not identifier parts.
  2461 
  2462 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2463   content of "..." to the latex file instead of \isacntrl... . The "..."
  2464   may consist of any printable characters excluding the end bracket >.
  2465 
  2466 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2467   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2468   declare constants "final", which prevents their being given a definition
  2469   later.  It is useful for constants whose behaviour is fixed axiomatically
  2470   rather than definitionally, such as the meta-logic connectives.
  2471 
  2472 * Pure: 'instance' now handles general arities with general sorts
  2473   (i.e. intersections of classes),
  2474 
  2475 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2476   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2477   It can be changed to alter the colors/layout of generated pages.
  2478 
  2479 
  2480 *** Isar ***
  2481 
  2482 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2483   cut_tac, subgoal_tac and thin_tac:
  2484   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2485     locales are no longer forced to write Isar proof scripts.
  2486     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2487     emulations.
  2488   - INCOMPATIBILITY: names of variables to be instantiated may no
  2489     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2490     This is consistent with the instantiation attribute "where".
  2491 
  2492 * Attributes "where" and "of":
  2493   - Now take type variables of instantiated theorem into account when reading
  2494     the instantiation string.  This fixes a bug that caused instantiated
  2495     theorems to have too special types in some circumstances.
  2496   - "where" permits explicit instantiations of type variables.
  2497 
  2498 * Calculation commands "moreover" and "also" no longer interfere with
  2499   current facts ("this"), admitting arbitrary combinations with "then"
  2500   and derived forms.
  2501 
  2502 * Locales:
  2503   - Goal statements involving the context element "includes" no longer
  2504     generate theorems with internal delta predicates (those ending on
  2505     "_axioms") in the premise.
  2506     Resolve particular premise with <locale>.intro to obtain old form.
  2507   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2508     specification and "includes" elements in goal statement.
  2509   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2510     [intro?] and [elim?] (respectively) by default.
  2511   - Experimental command for instantiation of locales in proof contexts:
  2512         instantiate <label>[<attrs>]: <loc>
  2513     Instantiates locale <loc> and adds all its theorems to the current context
  2514     taking into account their attributes.  Label and attrs are optional
  2515     modifiers, like in theorem declarations.  If present, names of
  2516     instantiated theorems are qualified with <label>, and the attributes
  2517     <attrs> are applied after any attributes these theorems might have already.
  2518       If the locale has assumptions, a chained fact of the form
  2519     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2520     are derived.  The command does not support old-style locales declared
  2521     with "locale (open)".
  2522       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2523 
  2524 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2525   (Isar) contexts.
  2526 
  2527 
  2528 *** HOL ***
  2529 
  2530 * Proof import: new image HOL4 contains the imported library from
  2531   the HOL4 system with about 2500 theorems. It is imported by
  2532   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2533   can be used like any other Isabelle image.  See
  2534   HOL/Import/HOL/README for more information.
  2535 
  2536 * Simplifier:
  2537   - Much improved handling of linear and partial orders.
  2538     Reasoners for linear and partial orders are set up for type classes
  2539     "linorder" and "order" respectively, and are added to the default simpset
  2540     as solvers.  This means that the simplifier can build transitivity chains
  2541     to solve goals from the assumptions.
  2542   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2543     of blast or auto after simplification become unnecessary because the goal
  2544     is solved by simplification already.
  2545 
  2546 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2547     all proved in axiomatic type classes for semirings, rings and fields.
  2548 
  2549 * Numerics:
  2550   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2551     now formalized using the Ring_and_Field theory mentioned above.
  2552   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2553     than before, because now they are set up once in a generic manner.
  2554   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2555     Look for the general versions in Ring_and_Field (and Power if they concern
  2556     exponentiation).
  2557 
  2558 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2559 
  2560 * Records:
  2561   - Record types are now by default printed with their type abbreviation
  2562     instead of the list of all field types. This can be configured via
  2563     the reference "print_record_type_abbr".
  2564   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2565     (not enabled by default).
  2566   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2567     EX x. x = sel r to True (not enabled by default).
  2568   - Tactic "record_split_simp_tac" to split and simplify records added.
  2569 
  2570 * 'specification' command added, allowing for definition by
  2571   specification.  There is also an 'ax_specification' command that
  2572   introduces the new constants axiomatically.
  2573 
  2574 * arith(_tac) is now able to generate counterexamples for reals as well.
  2575 
  2576 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2577 
  2578 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2579   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2580 
  2581 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2582   matrix theory to linear programming.
  2583 
  2584 * Unions and Intersections:
  2585   The latex output syntax of UN and INT has been changed
  2586   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2587   i.e. the index formulae has become a subscript.
  2588   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2589 
  2590 * Unions and Intersections over Intervals:
  2591   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2592   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2593   like in normal math, and corresponding versions for < and for intersection.
  2594 
  2595 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2596   lexicographic dictonary ordering has been added as "lexord".
  2597 
  2598 * ML: the legacy theory structures Int and List have been removed. They had
  2599   conflicted with ML Basis Library structures having the same names.
  2600 
  2601 * 'refute' command added to search for (finite) countermodels.  Only works
  2602   for a fragment of HOL.  The installation of an external SAT solver is
  2603   highly recommended.  See "HOL/Refute.thy" for details.
  2604 
  2605 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2606   formulae under an assignment of free variables to random values.
  2607   In contrast to 'refute', it can deal with inductive datatypes,
  2608   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2609   for examples.
  2610 
  2611 
  2612 *** HOLCF ***
  2613 
  2614 * Streams now come with concatenation and are part of the HOLCF image
  2615 
  2616 
  2617 
  2618 New in Isabelle2003 (May 2003)
  2619 ------------------------------
  2620 
  2621 *** General ***
  2622 
  2623 * Provers/simplifier:
  2624 
  2625   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2626     Assumptions are now subject to complete mutual simplification,
  2627     not just from left to right. The simplifier now preserves
  2628     the order of assumptions.
  2629 
  2630     Potential INCOMPATIBILITY:
  2631 
  2632     -- simp sometimes diverges where the old version did
  2633        not, e.g. invoking simp on the goal
  2634 
  2635         [| P (f x); y = x; f x = f y |] ==> Q
  2636 
  2637        now gives rise to the infinite reduction sequence
  2638 
  2639         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2640 
  2641        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2642        kind of problem.
  2643 
  2644     -- Tactics combining classical reasoner and simplification (such as auto)
  2645        are also affected by this change, because many of them rely on
  2646        simp. They may sometimes diverge as well or yield a different numbers
  2647        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2648        in case of problems. Sometimes subsequent calls to the classical
  2649        reasoner will fail because a preceeding call to the simplifier too
  2650        eagerly simplified the goal, e.g. deleted redundant premises.
  2651 
  2652   - The simplifier trace now shows the names of the applied rewrite rules
  2653 
  2654   - You can limit the number of recursive invocations of the simplifier
  2655     during conditional rewriting (where the simplifie tries to solve the
  2656     conditions before applying the rewrite rule):
  2657     ML "simp_depth_limit := n"
  2658     where n is an integer. Thus you can force termination where previously
  2659     the simplifier would diverge.
  2660 
  2661   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2662 
  2663   - No longer aborts on failed congruence proof.  Instead, the
  2664     congruence is ignored.
  2665 
  2666 * Pure: New generic framework for extracting programs from constructive
  2667   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2668   as HOL/Extraction for some case studies.
  2669 
  2670 * Pure: The main goal of the proof state is no longer shown by default, only
  2671 the subgoals. This behaviour is controlled by a new flag.
  2672    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2673 (ML: Proof.show_main_goal).
  2674 
  2675 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2676 rules whose conclusion matches subgoal 1:
  2677       PG menu: Isabelle/Isar -> Show me -> matching rules
  2678 The rules are ordered by how closely they match the subgoal.
  2679 In particular, rules that solve a subgoal outright are displayed first
  2680 (or rather last, the way they are printed).
  2681 (ML: ProofGeneral.print_intros())
  2682 
  2683 * Pure: New flag trace_unify_fail causes unification to print
  2684 diagnostic information (PG: in trace buffer) when it fails. This is
  2685 useful for figuring out why single step proofs like rule, erule or
  2686 assumption failed.
  2687 
  2688 * Pure: Locale specifications now produce predicate definitions
  2689 according to the body of text (covering assumptions modulo local
  2690 definitions); predicate "loc_axioms" covers newly introduced text,
  2691 while "loc" is cumulative wrt. all included locale expressions; the
  2692 latter view is presented only on export into the global theory
  2693 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2694 on the old view without predicates;
  2695 
  2696 * Pure: predefined locales "var" and "struct" are useful for sharing
  2697 parameters (as in CASL, for example); just specify something like
  2698 ``var x + var y + struct M'' as import;
  2699 
  2700 * Pure: improved thms_containing: proper indexing of facts instead of
  2701 raw theorems; check validity of results wrt. current name space;
  2702 include local facts of proof configuration (also covers active
  2703 locales), cover fixed variables in index; may use "_" in term
  2704 specification; an optional limit for the number of printed facts may
  2705 be given (the default is 40);
  2706 
  2707 * Pure: disallow duplicate fact bindings within new-style theory files
  2708 (batch-mode only);
  2709 
  2710 * Provers: improved induct method: assumptions introduced by case
  2711 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2712 the goal statement); "foo" still refers to all facts collectively;
  2713 
  2714 * Provers: the function blast.overloaded has been removed: all constants
  2715 are regarded as potentially overloaded, which improves robustness in exchange
  2716 for slight decrease in efficiency;
  2717 
  2718 * Provers/linorder: New generic prover for transitivity reasoning over
  2719 linear orders.  Note: this prover is not efficient!
  2720 
  2721 * Isar: preview of problems to finish 'show' now produce an error
  2722 rather than just a warning (in interactive mode);
  2723 
  2724 
  2725 *** HOL ***
  2726 
  2727 * arith(_tac)
  2728 
  2729  - Produces a counter example if it cannot prove a goal.
  2730    Note that the counter example may be spurious if the goal is not a formula
  2731    of quantifier-free linear arithmetic.
  2732    In ProofGeneral the counter example appears in the trace buffer.
  2733 
  2734  - Knows about div k and mod k where k is a numeral of type nat or int.
  2735 
  2736  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2737    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2738    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2739 
  2740 * simp's arithmetic capabilities have been enhanced a bit: it now
  2741 takes ~= in premises into account (by performing a case split);
  2742 
  2743 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2744 are distributed over a sum of terms;
  2745 
  2746 * New tactic "trans_tac" and method "trans" instantiate
  2747 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2748 "<=", "<" and "=").
  2749 
  2750 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2751 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2752 
  2753 * 'typedef' command has new option "open" to suppress the set
  2754 definition;
  2755 
  2756 * functions Min and Max on finite sets have been introduced (theory
  2757 Finite_Set);
  2758 
  2759 * attribute [symmetric] now works for relations as well; it turns
  2760 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2761 
  2762 * induct over a !!-quantified statement (say !!x1..xn):
  2763   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2764 
  2765 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2766 %x. None. Warning: empty_def now refers to the previously hidden definition
  2767 of the empty set.
  2768 
  2769 * Algebra: formalization of classical algebra.  Intended as base for
  2770 any algebraic development in Isabelle.  Currently covers group theory
  2771 (up to Sylow's theorem) and ring theory (Universal Property of
  2772 Univariate Polynomials).  Contributions welcome;
  2773 
  2774 * GroupTheory: deleted, since its material has been moved to Algebra;
  2775 
  2776 * Complex: new directory of the complex numbers with numeric constants,
  2777 nonstandard complex numbers, and some complex analysis, standard and
  2778 nonstandard (Jacques Fleuriot);
  2779 
  2780 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2781 
  2782 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2783 Fleuriot);
  2784 
  2785 * Real/HahnBanach: updated and adapted to locales;
  2786 
  2787 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2788 Gray and Kramer);
  2789 
  2790 * UNITY: added the Meier-Sanders theory of progress sets;
  2791 
  2792 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2793 as abstract algorithms, instantiated to the JVM;
  2794 
  2795 * Bali: Java source language formalization. Type system, operational
  2796 semantics, axiomatic semantics. Supported language features:
  2797 classes, interfaces, objects,virtual methods, static methods,
  2798 static/instance fields, arrays, access modifiers, definite
  2799 assignment, exceptions.
  2800 
  2801 
  2802 *** ZF ***
  2803 
  2804 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2805 universe, etc.);
  2806 
  2807 * Main ZF: virtually all theories converted to new-style format;
  2808 
  2809 
  2810 *** ML ***
  2811 
  2812 * Pure: Tactic.prove provides sane interface for internal proofs;
  2813 omits the infamous "standard" operation, so this is more appropriate
  2814 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2815 
  2816 * Pure: improved error reporting of simprocs;
  2817 
  2818 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2819 up simprocs;
  2820 
  2821 
  2822 *** Document preparation ***
  2823 
  2824 * uses \par instead of \\ for line breaks in theory text. This may
  2825 shift some page breaks in large documents. To get the old behaviour
  2826 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2827 
  2828 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2829 other packages
  2830 
  2831 * \<euro> now needs package babel/greek instead of marvosym (which
  2832 broke \Rightarrow)
  2833 
  2834 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2835 textcomp package)
  2836 
  2837 
  2838 
  2839 New in Isabelle2002 (March 2002)
  2840 --------------------------------
  2841 
  2842 *** Document preparation ***
  2843 
  2844 * greatly simplified document preparation setup, including more
  2845 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2846 instructive isatool mkdir; users should basically be able to get
  2847 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2848 users may run a separate document processing stage manually like this:
  2849 "isatool usedir -D output HOL Test && isatool document Test/output";
  2850 
  2851 * theory dependency graph may now be incorporated into documents;
  2852 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2853 with \includegraphics of LaTeX;
  2854 
  2855 * proper spacing of consecutive markup elements, especially text
  2856 blocks after section headings;
  2857 
  2858 * support bold style (for single symbols only), input syntax is like
  2859 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2860 
  2861 * \<bullet> is now output as bold \cdot by default, which looks much
  2862 better in printed text;
  2863 
  2864 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2865 note that these symbols are currently unavailable in Proof General /
  2866 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2867 
  2868 * isatool latex no longer depends on changed TEXINPUTS, instead
  2869 isatool document copies the Isabelle style files to the target
  2870 location;
  2871 
  2872 
  2873 *** Isar ***
  2874 
  2875 * Pure/Provers: improved proof by cases and induction;
  2876   - 'case' command admits impromptu naming of parameters (such as
  2877     "case (Suc n)");
  2878   - 'induct' method divinates rule instantiation from the inductive
  2879     claim; no longer requires excessive ?P bindings for proper
  2880     instantiation of cases;
  2881   - 'induct' method properly enumerates all possibilities of set/type
  2882     rules; as a consequence facts may be also passed through *type*
  2883     rules without further ado;
  2884   - 'induct' method now derives symbolic cases from the *rulified*
  2885     rule (before it used to rulify cases stemming from the internal
  2886     atomized version); this means that the context of a non-atomic
  2887     statement becomes is included in the hypothesis, avoiding the
  2888     slightly cumbersome show "PROP ?case" form;
  2889   - 'induct' may now use elim-style induction rules without chaining
  2890     facts, using ``missing'' premises from the goal state; this allows
  2891     rules stemming from inductive sets to be applied in unstructured
  2892     scripts, while still benefitting from proper handling of non-atomic
  2893     statements; NB: major inductive premises need to be put first, all
  2894     the rest of the goal is passed through the induction;
  2895   - 'induct' proper support for mutual induction involving non-atomic
  2896     rule statements (uses the new concept of simultaneous goals, see
  2897     below);
  2898   - append all possible rule selections, but only use the first
  2899     success (no backtracking);
  2900   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2901   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2902   - added 'print_induct_rules' (covered by help item in recent Proof
  2903     General versions);
  2904   - moved induct/cases attributes to Pure, methods to Provers;
  2905   - generic method setup instantiated for FOL and HOL;
  2906 
  2907 * Pure: support multiple simultaneous goal statements, for example
  2908 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2909 meta-level mechanism, this acts as if several individual goals had
  2910 been stated separately; in particular common proof methods need to be
  2911 repeated in order to cover all claims; note that a single elimination
  2912 step is *not* sufficient to establish the two conjunctions, so this
  2913 fails:
  2914 
  2915   assume "A & B" then have A and B ..   (*".." fails*)
  2916 
  2917 better use "obtain" in situations as above; alternative refer to
  2918 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2919 
  2920 * Pure: proper integration with ``locales''; unlike the original
  2921 version by Florian Kammller, Isar locales package high-level proof
  2922 contexts rather than raw logical ones (e.g. we admit to include
  2923 attributes everywhere); operations on locales include merge and
  2924 rename; support for implicit arguments (``structures''); simultaneous
  2925 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2926 some examples;
  2927 
  2928 * Pure: the following commands have been ``localized'', supporting a
  2929 target locale specification "(in name)": 'lemma', 'theorem',
  2930 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2931 stored both within the locale and at the theory level (exported and
  2932 qualified by the locale name);
  2933 
  2934 * Pure: theory goals may now be specified in ``long'' form, with
  2935 ad-hoc contexts consisting of arbitrary locale elements. for example
  2936 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2937 definitions may be given, too); the result is a meta-level rule with
  2938 the context elements being discharged in the obvious way;
  2939 
  2940 * Pure: new proof command 'using' allows to augment currently used
  2941 facts after a goal statement ('using' is syntactically analogous to
  2942 'apply', but acts on the goal's facts only); this allows chained facts
  2943 to be separated into parts given before and after a claim, as in
  2944 ``from a and b have C using d and e <proof>'';
  2945 
  2946 * Pure: renamed "antecedent" case to "rule_context";
  2947 
  2948 * Pure: new 'judgment' command records explicit information about the
  2949 object-logic embedding (used by several tools internally); no longer
  2950 use hard-wired "Trueprop";
  2951 
  2952 * Pure: added 'corollary' command;
  2953 
  2954 * Pure: fixed 'token_translation' command;
  2955 
  2956 * Pure: removed obsolete 'exported' attribute;
  2957 
  2958 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2959 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2960 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2961 
  2962 * Pure: method 'atomize' presents local goal premises as object-level
  2963 statements (atomic meta-level propositions); setup controlled via
  2964 rewrite rules declarations of 'atomize' attribute; example
  2965 application: 'induct' method with proper rule statements in improper
  2966 proof *scripts*;
  2967 
  2968 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2969 now consider the syntactic context of assumptions, giving a better
  2970 chance to get type-inference of the arguments right (this is
  2971 especially important for locales);
  2972 
  2973 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2974 mode;
  2975 
  2976 * Pure/obtain: the formal conclusion "thesis", being marked as
  2977 ``internal'', may no longer be reference directly in the text;
  2978 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2979 situations;
  2980 
  2981 * Pure: generic 'sym' attribute which declares a rule both as pure
  2982 'elim?' and for the 'symmetric' operation;
  2983 
  2984 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2985 text; the fixed correlation with particular command syntax has been
  2986 discontinued;
  2987 
  2988 * Pure: new method 'rules' is particularly well-suited for proof
  2989 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2990 but often produces more compact proof terms with less detours;
  2991 
  2992 * Pure/Provers/classical: simplified integration with pure rule
  2993 attributes and methods; the classical "intro?/elim?/dest?"
  2994 declarations coincide with the pure ones; the "rule" method no longer
  2995 includes classically swapped intros; "intro" and "elim" methods no
  2996 longer pick rules from the context; also got rid of ML declarations
  2997 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2998 INCOMPATIBILITY;
  2999 
  3000 * Provers/classical: attribute 'swapped' produces classical inversions
  3001 of introduction rules;
  3002 
  3003 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3004 rules instead of full simplifier context; 'iff' attribute handles
  3005 conditional rules;
  3006 
  3007 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3008 
  3009 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3010 "(permissive)" option to recover old behavior;
  3011 
  3012 * HOL: 'inductive' no longer features separate (collective) attributes
  3013 for 'intros' (was found too confusing);
  3014 
  3015 * HOL: properly declared induction rules less_induct and
  3016 wf_induct_rule;
  3017 
  3018 
  3019 *** HOL ***
  3020 
  3021 * HOL: moved over to sane numeral syntax; the new policy is as
  3022 follows:
  3023 
  3024   - 0 and 1 are polymorphic constants, which are defined on any
  3025   numeric type (nat, int, real etc.);
  3026 
  3027   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3028   binary representation internally;
  3029 
  3030   - type nat has special constructor Suc, and generally prefers Suc 0
  3031   over 1::nat and Suc (Suc 0) over 2::nat;
  3032 
  3033 This change may cause significant problems of INCOMPATIBILITY; here
  3034 are some hints on converting existing sources:
  3035 
  3036   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3037   entities, so expressions involving "-" (unary or binary minus) need
  3038   to be spaced properly;
  3039 
  3040   - existing occurrences of "1" may need to be constraint "1::nat" or
  3041   even replaced by Suc 0; similar for old "2";
  3042 
  3043   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3044 
  3045   - remove all special provisions on numerals in proofs;
  3046 
  3047 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3048 representation (depends on bin_arith_simps in the default context);
  3049 
  3050 * HOL: symbolic syntax for x^2 (numeral 2);
  3051 
  3052 * HOL: the class of all HOL types is now called "type" rather than
  3053 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3054 in axclass/classes, instance/arities, and (usually rare) occurrences
  3055 in typings (of consts etc.); internally the class is called
  3056 "HOL.type", ML programs should refer to HOLogic.typeS;
  3057 
  3058 * HOL/record package improvements:
  3059   - new derived operations "fields" to build a partial record section,
  3060     "extend" to promote a fixed record to a record scheme, and
  3061     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3062     declared as simp by default;
  3063   - shared operations ("more", "fields", etc.) now need to be always
  3064     qualified) --- potential INCOMPATIBILITY;
  3065   - removed "make_scheme" operations (use "make" with "extend") --
  3066     INCOMPATIBILITY;
  3067   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3068   - provides cases/induct rules for use with corresponding Isar
  3069     methods (for concrete records, record schemes, concrete more
  3070     parts, and schematic more parts -- in that order);
  3071   - internal definitions directly based on a light-weight abstract
  3072     theory of product types over typedef rather than datatype;
  3073 
  3074 * HOL: generic code generator for generating executable ML code from
  3075 specifications; specific support for HOL constructs such as inductive
  3076 datatypes and sets, as well as recursive functions; can be invoked
  3077 via 'generate_code' theory section;
  3078 
  3079 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3080 
  3081 * HOL: consolidated and renamed several theories.  In particular:
  3082         Ord.thy has been absorbed into HOL.thy
  3083         String.thy has been absorbed into List.thy
  3084 
  3085 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3086 (beware of argument permutation!);
  3087 
  3088 * HOL: linorder_less_split superseded by linorder_cases;
  3089 
  3090 * HOL/List: "nodups" renamed to "distinct";
  3091 
  3092 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3093 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3094   - Ex_def has changed, now need to use some_eq_ex
  3095 
  3096 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3097 in this (rare) case use:
  3098 
  3099   delSWrapper "split_all_tac"
  3100   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3101 
  3102 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3103 MAY FAIL;
  3104 
  3105 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3106 Isabelle's type classes, ^ on functions and relations has too general
  3107 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3108 necessary to attach explicit type constraints;
  3109 
  3110 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3111 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3112 renamed accordingly (eg "compI" -> "rel_compI").
  3113 
  3114 * HOL: syntax translations now work properly with numerals and records
  3115 expressions;
  3116 
  3117 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3118 of "lam" -- INCOMPATIBILITY;
  3119 
  3120 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3121 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3122 renamed "Product_Type.unit";
  3123 
  3124 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3125 
  3126 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3127 the "cases" method);
  3128 
  3129 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3130 Florian Kammller);
  3131 
  3132 * HOL/IMP: updated and converted to new-style theory format; several
  3133 parts turned into readable document, with proper Isar proof texts and
  3134 some explanations (by Gerwin Klein);
  3135 
  3136 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3137 
  3138 * HOL-Hyperreal is now a logic image;
  3139 
  3140 
  3141 *** HOLCF ***
  3142 
  3143 * Isar: consts/constdefs supports mixfix syntax for continuous
  3144 operations;
  3145 
  3146 * Isar: domain package adapted to new-style theory format, e.g. see
  3147 HOLCF/ex/Dnat.thy;
  3148 
  3149 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3150 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3151 lift.induct_tac, always use UU instead of Undef;
  3152 
  3153 * HOLCF/IMP: updated and converted to new-style theory;
  3154 
  3155 
  3156 *** ZF ***
  3157 
  3158 * Isar: proper integration of logic-specific tools and packages,
  3159 including theory commands '(co)inductive', '(co)datatype',
  3160 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3161 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3162 
  3163 * theory Main no longer includes AC; for the Axiom of Choice, base
  3164 your theory on Main_ZFC;
  3165 
  3166 * the integer library now covers quotients and remainders, with many
  3167 laws relating division to addition, multiplication, etc.;
  3168 
  3169 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3170 typeless version of the formalism;
  3171 
  3172 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3173 format;
  3174 
  3175 * ZF/Induct: new directory for examples of inductive definitions,
  3176 including theory Multiset for multiset orderings; converted to
  3177 new-style theory format;
  3178 
  3179 * ZF: many new theorems about lists, ordinals, etc.;
  3180 
  3181 
  3182 *** General ***
  3183 
  3184 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3185 variable proof controls level of detail: 0 = no proofs (only oracle
  3186 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3187 also ref manual for further ML interfaces;
  3188 
  3189 * Pure/axclass: removed obsolete ML interface
  3190 goal_subclass/goal_arity;
  3191 
  3192 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3193 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3194 separate tokens, so expressions involving minus need to be spaced
  3195 properly;
  3196 
  3197 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3198 rather than "infixl" or "infixr";
  3199 
  3200 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3201 sort constraint specifications in type inference; e.g. "x::_::foo"
  3202 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3203 type variable);
  3204 
  3205 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3206 control output of nested => (types); the default behavior is
  3207 "type_brackets";
  3208 
  3209 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3210 tokens into AST constants;
  3211 
  3212 * Pure/syntax: prefer later declarations of translations and print
  3213 translation functions; potential INCOMPATIBILITY: need to reverse
  3214 multiple declarations for same syntax element constant;
  3215 
  3216 * Pure/show_hyps reset by default (in accordance to existing Isar
  3217 practice);
  3218 
  3219 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3220 addSafter;
  3221 
  3222 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3223 as well;
  3224 
  3225 * system: tested support for MacOS X; should be able to get Isabelle +
  3226 Proof General to work in a plain Terminal after installing Poly/ML
  3227 (e.g. from the Isabelle distribution area) and GNU bash alone
  3228 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3229 support requires further installations, e.g. from
  3230 http://fink.sourceforge.net/);
  3231 
  3232 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3233 
  3234 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3235 of 40 MB), cf. ML_OPTIONS;
  3236 
  3237 * system: Proof General keywords specification is now part of the
  3238 Isabelle distribution (see etc/isar-keywords.el);
  3239 
  3240 * system: support for persistent Proof General sessions (refrain from
  3241 outdating all loaded theories on startup); user may create writable
  3242 logic images like this: ``isabelle -q HOL Test'';
  3243 
  3244 * system: smart selection of Isabelle process versus Isabelle
  3245 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3246 run both "isabelle" and "Isabelle" even if file names are badly
  3247 damaged (executable inspects the case of the first letter of its own
  3248 name); added separate "isabelle-process" and "isabelle-interface";
  3249 
  3250 * system: refrain from any attempt at filtering input streams; no
  3251 longer support ``8bit'' encoding of old isabelle font, instead proper
  3252 iso-latin characters may now be used; the related isatools
  3253 "symbolinput" and "nonascii" have disappeared as well;
  3254 
  3255 * system: removed old "xterm" interface (the print modes "xterm" and
  3256 "xterm_color" are still available for direct use in a suitable
  3257 terminal);
  3258 
  3259 
  3260 
  3261 New in Isabelle99-2 (February 2001)
  3262 -----------------------------------
  3263 
  3264 *** Overview of INCOMPATIBILITIES ***
  3265 
  3266 * HOL: please note that theories in the Library and elsewhere often use the
  3267 new-style (Isar) format; to refer to their theorems in an ML script you must
  3268 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3269 
  3270 * HOL: inductive package no longer splits induction rule aggressively,
  3271 but only as far as specified by the introductions given; the old
  3272 format may be recovered via ML function complete_split_rule or attribute
  3273 'split_rule (complete)';
  3274 
  3275 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3276 gfp_Tarski to gfp_unfold;
  3277 
  3278 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3279 
  3280 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3281 relation); infix "^^" has been renamed "``"; infix "``" has been
  3282 renamed "`"; "univalent" has been renamed "single_valued";
  3283 
  3284 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3285 operation;
  3286 
  3287 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3288 
  3289 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3290 
  3291 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3292 consequence, it is no longer monotonic wrt. the local goal context
  3293 (which is now passed through the inductive cases);
  3294 
  3295 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3296 \<gg> to \<ggreater>;
  3297 
  3298 
  3299 *** Document preparation ***
  3300 
  3301 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3302 available: are "it" for near math-mode best-style output, "sl" for
  3303 slanted text style, and "tt" for plain type-writer; if no
  3304 \isabellestyle command is given, output is according to slanted
  3305 type-writer);
  3306 
  3307 * support sub/super scripts (for single symbols only), input syntax is
  3308 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3309 
  3310 * some more standard symbols; see Appendix A of the system manual for
  3311 the complete list of symbols defined in isabellesym.sty;
  3312 
  3313 * improved isabelle style files; more abstract symbol implementation
  3314 (should now use \isamath{...} and \isatext{...} in custom symbol
  3315 definitions);
  3316 
  3317 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3318 state; Note that presentation of goal states does not conform to
  3319 actual human-readable proof documents.  Please do not include goal
  3320 states into document output unless you really know what you are doing!
  3321 
  3322 * proper indentation of antiquoted output with proportional LaTeX
  3323 fonts;
  3324 
  3325 * no_document ML operator temporarily disables LaTeX document
  3326 generation;
  3327 
  3328 * isatool unsymbolize tunes sources for plain ASCII communication;
  3329 
  3330 
  3331 *** Isar ***
  3332 
  3333 * Pure: Isar now suffers initial goal statements to contain unbound
  3334 schematic variables (this does not conform to actual readable proof
  3335 documents, due to unpredictable outcome and non-compositional proof
  3336 checking); users who know what they are doing may use schematic goals
  3337 for Prolog-style synthesis of proven results;
  3338 
  3339 * Pure: assumption method (an implicit finishing) now handles actual
  3340 rules as well;
  3341 
  3342 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3343 initial goal, declare "that" only as Pure intro (only for single
  3344 steps); the "that" rule assumption may now be involved in implicit
  3345 finishing, thus ".." becomes a feasible for trivial obtains;
  3346 
  3347 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3348 instance proofs may be performed by "..";
  3349 
  3350 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3351 statements as well;
  3352 
  3353 * Pure: more robust selection of calculational rules;
  3354 
  3355 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3356 rule (as well as the assumption rule);
  3357 
  3358 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3359 lemmas, using the graph browser tool;
  3360 
  3361 * Pure: predict failure of "show" in interactive mode;
  3362 
  3363 * Pure: 'thms_containing' now takes actual terms as arguments;
  3364 
  3365 * HOL: improved method 'induct' --- now handles non-atomic goals
  3366 (potential INCOMPATIBILITY); tuned error handling;
  3367 
  3368 * HOL: cases and induct rules now provide explicit hints about the
  3369 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3370 any remaining facts are inserted into the goal verbatim;
  3371 
  3372 * HOL: local contexts (aka cases) may now contain term bindings as
  3373 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3374 the result to be shown in each case;
  3375 
  3376 * HOL: added 'recdef_tc' command;
  3377 
  3378 * isatool convert assists in eliminating legacy ML scripts;
  3379 
  3380 
  3381 *** HOL ***
  3382 
  3383 * HOL/Library: a collection of generic theories to be used together
  3384 with main HOL; the theory loader path already includes this directory
  3385 by default; the following existing theories have been moved here:
  3386 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3387 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3388 
  3389 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3390 modelling and verification task performed in Isabelle/HOL +
  3391 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3392 
  3393 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3394 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3395 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3396 'domain', this makes the theory consistent with mathematical
  3397 literature;
  3398 
  3399 * HOL basics: added overloaded operations "inverse" and "divide"
  3400 (infix "/"), syntax for generic "abs" operation, generic summation
  3401 operator \<Sum>;
  3402 
  3403 * HOL/typedef: simplified package, provide more useful rules (see also
  3404 HOL/subset.thy);
  3405 
  3406 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3407 now expressed as a proper nested rule (old-style tactic scripts may
  3408 require atomize_strip_tac to cope with non-atomic premises);
  3409 
  3410 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3411 to "split_conv" (old name still available for compatibility);
  3412 
  3413 * HOL: improved concrete syntax for strings (e.g. allows translation
  3414 rules with string literals);
  3415 
  3416 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3417  and Fleuriot's mechanization of analysis, including the transcendental
  3418  functions for the reals;
  3419 
  3420 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3421 
  3422 
  3423 *** CTT ***
  3424 
  3425 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3426 "lam" is displayed as TWO lambda-symbols
  3427 
  3428 * CTT: theory Main now available, containing everything (that is, Bool
  3429 and Arith);
  3430 
  3431 
  3432 *** General ***
  3433 
  3434 * Pure: the Simplifier has been implemented properly as a derived rule
  3435 outside of the actual kernel (at last!); the overall performance
  3436 penalty in practical applications is about 50%, while reliability of
  3437 the Isabelle inference kernel has been greatly improved;
  3438 
  3439 * print modes "brackets" and "no_brackets" control output of nested =>
  3440 (types) and ==> (props); the default behaviour is "brackets";
  3441 
  3442 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3443 as assumptions as well;
  3444 
  3445 * system: support Poly/ML 4.0;
  3446 
  3447 * system: isatool install handles KDE version 1 or 2;
  3448 
  3449 
  3450 
  3451 New in Isabelle99-1 (October 2000)
  3452 ----------------------------------
  3453 
  3454 *** Overview of INCOMPATIBILITIES ***
  3455 
  3456 * HOL: simplification of natural numbers is much changed; to partly
  3457 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3458 issue the following ML commands:
  3459 
  3460   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3461   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3462 
  3463 * HOL: simplification no longer dives into case-expressions; this is
  3464 controlled by "t.weak_case_cong" for each datatype t;
  3465 
  3466 * HOL: nat_less_induct renamed to less_induct;
  3467 
  3468 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3469 fixsome to patch .thy and .ML sources automatically;
  3470 
  3471   select_equality  -> some_equality
  3472   select_eq_Ex     -> some_eq_ex
  3473   selectI2EX       -> someI2_ex
  3474   selectI2         -> someI2
  3475   selectI          -> someI
  3476   select1_equality -> some1_equality
  3477   Eps_sym_eq       -> some_sym_eq_trivial
  3478   Eps_eq           -> some_eq_trivial
  3479 
  3480 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3481 
  3482 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3483 instead);
  3484 
  3485 * HOL: the recursion equations generated by 'recdef' are now called
  3486 f.simps instead of f.rules;
  3487 
  3488 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3489 
  3490 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3491 sometimes be needed;
  3492 
  3493 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3494 
  3495 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3496 
  3497 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3498 product is now "<*>" instead of "Times"; the lexicographic product is
  3499 now "<*lex*>" instead of "**";
  3500 
  3501 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3502 of main HOL, but was unused); better use HOL's datatype package;
  3503 
  3504 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3505 the old syntax may be recovered as follows:
  3506 
  3507   syntax (symbols)
  3508     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3509       (infixl "\\<oplus>" 100)
  3510 
  3511 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3512 
  3513 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3514 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3515 internally;
  3516 
  3517 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3518 changed from A/r to A//r;
  3519 
  3520 * ZF: new treatment of arithmetic (nat & int) may break some old
  3521 proofs;
  3522 
  3523 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3524 rulify -> rule_format, elimify -> elim_format, ...);
  3525 
  3526 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3527 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3528 should have to change intro!! to intro? only); replaced "delrule" by
  3529 "rule del";
  3530 
  3531 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3532 
  3533 * Provers: strengthened force_tac by using new first_best_tac;
  3534 
  3535 * LaTeX document preparation: several changes of isabelle.sty (see
  3536 lib/texinputs);
  3537 
  3538 
  3539 *** Document preparation ***
  3540 
  3541 * formal comments (text blocks etc.) in new-style theories may now
  3542 contain antiquotations of thm/prop/term/typ/text to be presented
  3543 according to latex print mode; concrete syntax is like this:
  3544 @{term[show_types] "f(x) = a + x"};
  3545 
  3546 * isatool mkdir provides easy setup of Isabelle session directories,
  3547 including proper document sources;
  3548 
  3549 * generated LaTeX sources are now deleted after successful run
  3550 (isatool document -c); may retain a copy somewhere else via -D option
  3551 of isatool usedir;
  3552 
  3553 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3554 style files, achieving self-contained LaTeX sources and simplifying
  3555 LaTeX debugging;
  3556 
  3557 * old-style theories now produce (crude) LaTeX output as well;
  3558 
  3559 * browser info session directories are now self-contained (may be put
  3560 on WWW server seperately); improved graphs of nested sessions; removed
  3561 graph for 'all sessions';
  3562 
  3563 * several improvements in isabelle style files; \isabellestyle{it}
  3564 produces fake math mode output; \isamarkupheader is now \section by
  3565 default; see lib/texinputs/isabelle.sty etc.;
  3566 
  3567 
  3568 *** Isar ***
  3569 
  3570 * Isar/Pure: local results and corresponding term bindings are now
  3571 subject to Hindley-Milner polymorphism (similar to ML); this
  3572 accommodates incremental type-inference very nicely;
  3573 
  3574 * Isar/Pure: new derived language element 'obtain' supports
  3575 generalized existence reasoning;
  3576 
  3577 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3578 support accumulation of results, without applying any rules yet;
  3579 useful to collect intermediate results without explicit name
  3580 references, and for use with transitivity rules with more than 2
  3581 premises;
  3582 
  3583 * Isar/Pure: scalable support for case-analysis type proofs: new
  3584 'case' language element refers to local contexts symbolically, as
  3585 produced by certain proof methods; internally, case names are attached
  3586 to theorems as "tags";
  3587 
  3588 * Isar/Pure: theory command 'hide' removes declarations from
  3589 class/type/const name spaces;
  3590 
  3591 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3592 indicate potential overloading;
  3593 
  3594 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3595 
  3596 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3597 "{a,b,c}" instead of {a,b,c};
  3598 
  3599 * Isar/Pure now provides its own version of intro/elim/dest
  3600 attributes; useful for building new logics, but beware of confusion
  3601 with the version in Provers/classical;
  3602 
  3603 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3604 case name 'antecedent';
  3605 
  3606 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3607 to the current context is now done automatically);
  3608 
  3609 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3610 for definining proof methods in ML;
  3611 
  3612 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3613 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3614 most cases, one should have to change intro!! to intro? only);
  3615 replaced "delrule" by "rule del";
  3616 
  3617 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3618 'symmetric' attribute (the latter supercedes [RS sym]);
  3619 
  3620 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3621 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3622 well (including splits);
  3623 
  3624 * Isar/Provers: Simplifier and Classical methods now support all kind
  3625 of modifiers used in the past, including 'cong', 'iff', etc.
  3626 
  3627 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3628 of Simplifier and Classical reasoner);
  3629 
  3630 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3631 now support named cases; major packages (inductive, datatype, primrec,
  3632 recdef) support case names and properly name parameters;
  3633 
  3634 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3635 monotonicity conditions are extracted to be proven at end of
  3636 calculations;
  3637 
  3638 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3639 method anyway;
  3640 
  3641 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3642 split_if split_if_asm; datatype package provides theorems foo.splits =
  3643 foo.split foo.split_asm for each datatype;
  3644 
  3645 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3646 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3647 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3648 use "(cases (simplified))" method in proper proof texts);
  3649 
  3650 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3651 
  3652 * Isar: names of theorems etc. may be natural numbers as well;
  3653 
  3654 * Isar: 'pr' command: optional arguments for goals_limit and
  3655 ProofContext.prems_limit; no longer prints theory contexts, but only
  3656 proof states;
  3657 
  3658 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3659 additional print modes to be specified; e.g. "pr(latex)" will print
  3660 proof state according to the Isabelle LaTeX style;
  3661 
  3662 * Isar: improved support for emulating tactic scripts, including proof
  3663 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3664 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3665 (for HOL datatypes);
  3666 
  3667 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3668 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3669 'proof method scripts' have to be in depth-first order;
  3670 
  3671 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3672 
  3673 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3674 should instead use individual commands for printing items
  3675 (print_commands, print_methods etc.);
  3676 
  3677 * Isar: added 'nothing' --- the empty list of theorems;
  3678 
  3679 
  3680 *** HOL ***
  3681 
  3682 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3683 corresponding virtual machine and a specification of its bytecode
  3684 verifier and a lightweight bytecode verifier, including proofs of
  3685 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3686 Cornelia Pusch (see also the homepage of project Bali at
  3687 http://isabelle.in.tum.de/Bali/);
  3688 
  3689 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3690 Clemens Ballarin;
  3691 
  3692 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3693 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3694 Rasmussen;
  3695 
  3696 * HOL/Lattice: fundamental concepts of lattice theory and order
  3697 structures, including duals, properties of bounds versus algebraic
  3698 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3699 Theorem for complete lattices etc.; may also serve as a demonstration
  3700 for abstract algebraic reasoning using axiomatic type classes, and
  3701 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3702 
  3703 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3704 von Oheimb;
  3705 
  3706 * HOL/IMPP: extension of IMP with local variables and mutually
  3707 recursive procedures, by David von Oheimb;
  3708 
  3709 * HOL/Lambda: converted into new-style theory and document;
  3710 
  3711 * HOL/ex/Multiquote: example of multiple nested quotations and
  3712 anti-quotations -- basically a generalized version of de-Bruijn
  3713 representation; very useful in avoiding lifting of operations;
  3714 
  3715 * HOL/record: added general record equality rule to simpset; fixed
  3716 select-update simplification procedure to handle extended records as
  3717 well; admit "r" as field name;
  3718 
  3719 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3720 other numeric types and also as the identity of groups, rings, etc.;
  3721 
  3722 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3723 Types nat and int belong to this axclass;
  3724 
  3725 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3726    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3727    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3728   two terms #m*u and #n*u are replaced by #(m+n)*u
  3729     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3730   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3731     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3732 
  3733 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3734 powerful prover for predicate logic but knows nothing of clasets; see
  3735 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3736 
  3737 * HOL: new version of "case_tac" subsumes both boolean case split and
  3738 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3739 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3740 
  3741 * HOL: simplification no longer dives into case-expressions: only the
  3742 selector expression is simplified, but not the remaining arms; to
  3743 enable full simplification of case-expressions for datatype t, you may
  3744 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3745 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3746 
  3747 * HOL/recdef: the recursion equations generated by 'recdef' for
  3748 function 'f' are now called f.simps instead of f.rules; if all
  3749 termination conditions are proved automatically, these simplification
  3750 rules are added to the simpset, as in primrec; rules may be named
  3751 individually as well, resulting in a separate list of theorems for
  3752 each equation;
  3753 
  3754 * HOL/While is a new theory that provides a while-combinator. It
  3755 permits the definition of tail-recursive functions without the
  3756 provision of a termination measure. The latter is necessary once the
  3757 invariant proof rule for while is applied.
  3758 
  3759 * HOL: new (overloaded) notation for the set of elements below/above
  3760 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3761 
  3762 * HOL: theorems impI, allI, ballI bound as "strip";
  3763 
  3764 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3765 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3766 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3767 
  3768 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3769 
  3770 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3771 main HOL, but was unused);
  3772 
  3773 * HOL: fewer consts declared as global (e.g. have to refer to
  3774 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3775 
  3776 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3777 in case of overlap with user translations (e.g. judgements over
  3778 tuples); (note that the underlying logical represenation is still
  3779 bogus);
  3780 
  3781 
  3782 *** ZF ***
  3783 
  3784 * ZF: simplification automatically cancels common terms in arithmetic
  3785 expressions over nat and int;
  3786 
  3787 * ZF: new treatment of nat to minimize type-checking: all operators
  3788 coerce their operands to a natural number using the function natify,
  3789 making the algebraic laws unconditional;
  3790 
  3791 * ZF: as above, for int: operators coerce their operands to an integer
  3792 using the function intify;
  3793 
  3794 * ZF: the integer library now contains many of the usual laws for the
  3795 orderings, including $<=, and monotonicity laws for $+ and $*;
  3796 
  3797 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3798 simplification;
  3799 
  3800 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3801 to the simplifier and classical reasoner simultaneously;
  3802 
  3803 
  3804 *** General ***
  3805 
  3806 * Provers: blast_tac now handles actual object-logic rules as
  3807 assumptions; note that auto_tac uses blast_tac internally as well;
  3808 
  3809 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3810 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3811 
  3812 * Provers: delrules now handles destruct rules as well (no longer need
  3813 explicit make_elim);
  3814 
  3815 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3816   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3817 use instead the strong form,
  3818   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3819 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3820 from destruct-rules;
  3821 
  3822 * Provers: Simplifier.easy_setup provides a fast path to basic
  3823 Simplifier setup for new object-logics;
  3824 
  3825 * Pure: AST translation rules no longer require constant head on LHS;
  3826 
  3827 * Pure: improved name spaces: ambiguous output is qualified; support
  3828 for hiding of names;
  3829 
  3830 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3831 XSYMBOL_HOME; no longer need to do manual configuration in most
  3832 situations;
  3833 
  3834 * system: compression of ML heaps images may now be controlled via -c
  3835 option of isabelle and isatool usedir (currently only observed by
  3836 Poly/ML);
  3837 
  3838 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3839 useful for remote X11);
  3840 
  3841 * system: provide TAGS file for Isabelle sources;
  3842 
  3843 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3844 order;
  3845 
  3846 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3847 timing flag supersedes proof_timing and Toplevel.trace;
  3848 
  3849 * ML: new combinators |>> and |>>> for incremental transformations
  3850 with secondary results (e.g. certain theory extensions):
  3851 
  3852 * ML: PureThy.add_defs gets additional argument to indicate potential
  3853 overloading (usually false);
  3854 
  3855 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3856 results;
  3857 
  3858 
  3859 
  3860 New in Isabelle99 (October 1999)
  3861 --------------------------------
  3862 
  3863 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3864 
  3865 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3866 are no longer simplified.  (This allows the simplifier to unfold recursive
  3867 functional programs.)  To restore the old behaviour, declare
  3868 
  3869     Delcongs [if_weak_cong];
  3870 
  3871 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3872 complement;
  3873 
  3874 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3875 
  3876 * HOL/datatype: mutual_induct_tac no longer exists --
  3877   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3878 
  3879 * HOL/typedef: fixed type inference for representing set; type
  3880 arguments now have to occur explicitly on the rhs as type constraints;
  3881 
  3882 * ZF: The con_defs part of an inductive definition may no longer refer
  3883 to constants declared in the same theory;
  3884 
  3885 * HOL, ZF: the function mk_cases, generated by the inductive
  3886 definition package, has lost an argument.  To simplify its result, it
  3887 uses the default simpset instead of a supplied list of theorems.
  3888 
  3889 * HOL/List: the constructors of type list are now Nil and Cons;
  3890 
  3891 * Simplifier: the type of the infix ML functions
  3892         setSSolver addSSolver setSolver addSolver
  3893 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3894 for packaging solvers. A solver is created via
  3895         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3896 where the string argument is only a comment.
  3897 
  3898 
  3899 *** Proof tools ***
  3900 
  3901 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3902 decision procedure for linear arithmetic. Currently it is used for
  3903 types `nat', `int', and `real' in HOL (see below); it can, should and
  3904 will be instantiated for other types and logics as well.
  3905 
  3906 * The simplifier now accepts rewrite rules with flexible heads, eg
  3907      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3908   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3909   matching.
  3910 
  3911 
  3912 *** General ***
  3913 
  3914 * New Isabelle/Isar subsystem provides an alternative to traditional
  3915 tactical theorem proving; together with the ProofGeneral/isar user
  3916 interface it offers an interactive environment for developing human
  3917 readable proof documents (Isar == Intelligible semi-automated
  3918 reasoning); for further information see isatool doc isar-ref,
  3919 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3920 
  3921 * improved and simplified presentation of theories: better HTML markup
  3922 (including colors), graph views in several sizes; isatool usedir now
  3923 provides a proper interface for user theories (via -P option); actual
  3924 document preparation based on (PDF)LaTeX is available as well (for
  3925 new-style theories only); see isatool doc system for more information;
  3926 
  3927 * native support for Proof General, both for classic Isabelle and
  3928 Isabelle/Isar;
  3929 
  3930 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3931 using the graph browser tool;
  3932 
  3933 * Isabelle manuals now also available as PDF;
  3934 
  3935 * theory loader rewritten from scratch (may not be fully
  3936 bug-compatible); old loadpath variable has been replaced by show_path,
  3937 add_path, del_path, reset_path functions; new operations such as
  3938 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3939 isatool doc ref);
  3940 
  3941 * improved isatool install: option -k creates KDE application icon,
  3942 option -p DIR installs standalone binaries;
  3943 
  3944 * added ML_PLATFORM setting (useful for cross-platform installations);
  3945 more robust handling of platform specific ML images for SML/NJ;
  3946 
  3947 * the settings environment is now statically scoped, i.e. it is never
  3948 created again in sub-processes invoked from isabelle, isatool, or
  3949 Isabelle;
  3950 
  3951 * path element specification '~~' refers to '$ISABELLE_HOME';
  3952 
  3953 * in locales, the "assumes" and "defines" parts may be omitted if
  3954 empty;
  3955 
  3956 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3957 long arrows);
  3958 
  3959 * new print_mode "HTML";
  3960 
  3961 * new flag show_tags controls display of tags of theorems (which are
  3962 basically just comments that may be attached by some tools);
  3963 
  3964 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3965 mode and goal output format:
  3966 
  3967 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3968 244c244
  3969 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3970 ---
  3971 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3972 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3973 181c181
  3974 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3975 ---
  3976 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3977 
  3978 * function bind_thms stores lists of theorems (cf. bind_thm);
  3979 
  3980 * new shorthand tactics ftac, eatac, datac, fatac;
  3981 
  3982 * qed (and friends) now accept "" as result name; in that case the
  3983 theorem is not stored, but proper checks and presentation of the
  3984 result still apply;
  3985 
  3986 * theorem database now also indexes constants "Trueprop", "all",
  3987 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3988 
  3989 
  3990 *** HOL ***
  3991 
  3992 ** HOL arithmetic **
  3993 
  3994 * There are now decision procedures for linear arithmetic over nat and
  3995 int:
  3996 
  3997 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3998 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3999 are treated as atomic; subformulae not involving type `nat' or `int'
  4000 are ignored; quantified subformulae are ignored unless they are
  4001 positive universal or negative existential. The tactic has to be
  4002 invoked by hand and can be a little bit slow. In particular, the
  4003 running time is exponential in the number of occurrences of `min' and
  4004 `max', and `-' on `nat'.
  4005 
  4006 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4007 (negated) (in)equalities among the premises and the conclusion into
  4008 account (i.e. no compound formulae) and does not know about `min' and
  4009 `max', and `-' on `nat'. It is fast and is used automatically by the
  4010 simplifier.
  4011 
  4012 NB: At the moment, these decision procedures do not cope with mixed
  4013 nat/int formulae where the two parts interact, such as `m < n ==>
  4014 int(m) < int(n)'.
  4015 
  4016 * HOL/Numeral provides a generic theory of numerals (encoded
  4017 efficiently as bit strings); setup for types nat/int/real is in place;
  4018 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4019 int, existing theories and proof scripts may require a few additional
  4020 type constraints;
  4021 
  4022 * integer division and remainder can now be performed on constant
  4023 arguments;
  4024 
  4025 * many properties of integer multiplication, division and remainder
  4026 are now available;
  4027 
  4028 * An interface to the Stanford Validity Checker (SVC) is available through the
  4029 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4030 are proved automatically.  SVC must be installed separately, and its results
  4031 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4032 invocation of the underlying oracle).  For SVC see
  4033   http://verify.stanford.edu/SVC
  4034 
  4035 * IsaMakefile: the HOL-Real target now builds an actual image;
  4036 
  4037 
  4038 ** HOL misc **
  4039 
  4040 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4041 (in Isabelle/Isar) -- by Gertrud Bauer;
  4042 
  4043 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4044 analysis for assembly languages with subtypes;
  4045 
  4046 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4047 -- avoids syntactic ambiguities and treats state, transition, and
  4048 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4049 changed syntax and (many) tactics;
  4050 
  4051 * HOL/inductive: Now also handles more general introduction rules such
  4052   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4053   theorems are now maintained within the theory (maintained via the
  4054   "mono" attribute);
  4055 
  4056 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4057   (using function types) such as
  4058 
  4059   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4060 
  4061 * HOL/record: record_simproc (part of the default simpset) takes care
  4062 of selectors applied to updated records; record_split_tac is no longer
  4063 part of the default claset; update_defs may now be removed from the
  4064 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4065 
  4066   claset_ref () := claset() addSWrapper record_split_wrapper;
  4067   Delsimprocs [record_simproc]
  4068 
  4069 * HOL/typedef: fixed type inference for representing set; type
  4070 arguments now have to occur explicitly on the rhs as type constraints;
  4071 
  4072 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4073 names rather than an ML expression;
  4074 
  4075 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4076 supplied later.  Program schemes can be defined, such as
  4077     "While B C s = (if B s then While B C (C s) else s)"
  4078 where the well-founded relation can be chosen after B and C have been given.
  4079 
  4080 * HOL/List: the constructors of type list are now Nil and Cons;
  4081 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4082 course, ML tools referring to List.list.op # etc. have to be adapted;
  4083 
  4084 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4085 disabled by default; run isabelle with option -m HOL to get back to
  4086 the original Gordon/HOL-style output;
  4087 
  4088 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4089 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4090 
  4091 * HOL basic syntax simplified (more orthogonal): all variants of
  4092 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4093 Eps operator is provided as well: "SOME x. P[x]";
  4094 
  4095 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4096 
  4097 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4098 thus available for user theories;
  4099 
  4100 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4101 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4102 time;
  4103 
  4104 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4105 several times and then mp;
  4106 
  4107 
  4108 *** LK ***
  4109 
  4110 * the notation <<...>> is now available as a notation for sequences of
  4111 formulas;
  4112 
  4113 * the simplifier is now installed
  4114 
  4115 * the axiom system has been generalized (thanks to Soren Heilmann)
  4116 
  4117 * the classical reasoner now has a default rule database
  4118 
  4119 
  4120 *** ZF ***
  4121 
  4122 * new primrec section allows primitive recursive functions to be given
  4123 directly (as in HOL) over datatypes and the natural numbers;
  4124 
  4125 * new tactics induct_tac and exhaust_tac for induction (or case
  4126 analysis) over datatypes and the natural numbers;
  4127 
  4128 * the datatype declaration of type T now defines the recursor T_rec;
  4129 
  4130 * simplification automatically does freeness reasoning for datatype
  4131 constructors;
  4132 
  4133 * automatic type-inference, with AddTCs command to insert new
  4134 type-checking rules;
  4135 
  4136 * datatype introduction rules are now added as Safe Introduction rules
  4137 to the claset;
  4138 
  4139 * the syntax "if P then x else y" is now available in addition to
  4140 if(P,x,y);
  4141 
  4142 
  4143 *** Internal programming interfaces ***
  4144 
  4145 * tuned simplifier trace output; new flag debug_simp;
  4146 
  4147 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4148 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4149 
  4150 * AxClass.axclass_tac lost the theory argument;
  4151 
  4152 * tuned current_goals_markers semantics: begin / end goal avoids
  4153 printing empty lines;
  4154 
  4155 * removed prs and prs_fn hook, which was broken because it did not
  4156 include \n in its semantics, forcing writeln to add one
  4157 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4158 string -> unit if you really want to output text without newline;
  4159 
  4160 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4161 plain output, interface builders may have to enable 'isabelle_font'
  4162 mode to get Isabelle font glyphs as before;
  4163 
  4164 * refined token_translation interface; INCOMPATIBILITY: output length
  4165 now of type real instead of int;
  4166 
  4167 * theory loader actions may be traced via new ThyInfo.add_hook
  4168 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4169 your own database of information attached to *whole* theories -- as
  4170 opposed to intra-theory data slots offered via TheoryDataFun;
  4171 
  4172 * proper handling of dangling sort hypotheses (at last!);
  4173 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4174 extra sort hypotheses that can be witnessed from the type signature;
  4175 the force_strip_shyps flag is gone, any remaining shyps are simply
  4176 left in the theorem (with a warning issued by strip_shyps_warning);
  4177 
  4178 
  4179 
  4180 New in Isabelle98-1 (October 1998)
  4181 ----------------------------------
  4182 
  4183 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4184 
  4185 * several changes of automated proof tools;
  4186 
  4187 * HOL: major changes to the inductive and datatype packages, including
  4188 some minor incompatibilities of theory syntax;
  4189 
  4190 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4191 called `inj_on';
  4192 
  4193 * HOL: removed duplicate thms in Arith:
  4194   less_imp_add_less  should be replaced by  trans_less_add1
  4195   le_imp_add_le      should be replaced by  trans_le_add1
  4196 
  4197 * HOL: unary minus is now overloaded (new type constraints may be
  4198 required);
  4199 
  4200 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4201 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4202 now taken as an integer constant.
  4203 
  4204 * Pure: ML function 'theory_of' renamed to 'theory';
  4205 
  4206 
  4207 *** Proof tools ***
  4208 
  4209 * Simplifier:
  4210   1. Asm_full_simp_tac is now more aggressive.
  4211      1. It will sometimes reorient premises if that increases their power to
  4212         simplify.
  4213      2. It does no longer proceed strictly from left to right but may also
  4214         rotate premises to achieve further simplification.
  4215      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4216      old Asm_full_simp_tac in that it does not rotate premises.
  4217   2. The simplifier now knows a little bit about nat-arithmetic.
  4218 
  4219 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4220 allows for selected deletion of wrappers, by introduction of names for
  4221 wrapper functionals.  This implies that addbefore, addSbefore,
  4222 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4223 and that adding two tactics with the same name overwrites the first
  4224 one (emitting a warning).
  4225   type wrapper = (int -> tactic) -> (int -> tactic)
  4226   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4227   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4228   delWrapper, delSWrapper: claset *  string            -> claset
  4229   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4230 
  4231 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4232 semantics; addbefore now affects only the unsafe part of step_tac
  4233 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4234 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4235 by Force_tac;
  4236 
  4237 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4238 compWrapper; added safe wrapper (and access functions for it);
  4239 
  4240 * HOL/split_all_tac is now much faster and fails if there is nothing
  4241 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4242 and the names of the automatically generated variables have changed.
  4243 split_all_tac has moved within claset() from unsafe wrappers to safe
  4244 wrappers, which means that !!-bound variables are split much more
  4245 aggressively, and safe_tac and clarify_tac now split such variables.
  4246 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4247 Note: the same holds for record_split_tac, which does the job of
  4248 split_all_tac for record fields.
  4249 
  4250 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4251 permanently to the default simpset using Addsplits just like
  4252 Addsimps. They can be removed via Delsplits just like
  4253 Delsimps. Lower-case versions are also available.
  4254 
  4255 * HOL/Simplifier: The rule split_if is now part of the default
  4256 simpset. This means that the simplifier will eliminate all occurrences
  4257 of if-then-else in the conclusion of a goal. To prevent this, you can
  4258 either remove split_if completely from the default simpset by
  4259 `Delsplits [split_if]' or remove it in a specific call of the
  4260 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4261 other case splitting rules to/from the default simpset: every datatype
  4262 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4263 t is the name of the datatype).
  4264 
  4265 * Classical reasoner / Simplifier combination: new force_tac (and
  4266 derivatives Force_tac, force) combines rewriting and classical
  4267 reasoning (and whatever other tools) similarly to auto_tac, but is
  4268 aimed to solve the given subgoal completely.
  4269 
  4270 
  4271 *** General ***
  4272 
  4273 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4274 and `goalw': the theory is no longer needed as an explicit argument -
  4275 the current theory context is used; assumptions are no longer returned
  4276 at the ML-level unless one of them starts with ==> or !!; it is
  4277 recommended to convert to these new commands using isatool fixgoal
  4278 (backup your sources first!);
  4279 
  4280 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4281 the current theory context, and 'theory' to lookup stored theories;
  4282 
  4283 * new theory section 'locale' for declaring constants, assumptions and
  4284 definitions that have local scope;
  4285 
  4286 * new theory section 'nonterminals' for purely syntactic types;
  4287 
  4288 * new theory section 'setup' for generic ML setup functions
  4289 (e.g. package initialization);
  4290 
  4291 * the distribution now includes Isabelle icons: see
  4292 lib/logo/isabelle-{small,tiny}.xpm;
  4293 
  4294 * isatool install - install binaries with absolute references to
  4295 ISABELLE_HOME/bin;
  4296 
  4297 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4298 
  4299 * print mode 'emacs' reserved for Isamode;
  4300 
  4301 * support multiple print (ast) translations per constant name;
  4302 
  4303 * theorems involving oracles are now printed with a suffixed [!];
  4304 
  4305 
  4306 *** HOL ***
  4307 
  4308 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4309 
  4310 * HOL/inductive package reorganized and improved: now supports mutual
  4311 definitions such as
  4312 
  4313   inductive EVEN ODD
  4314     intrs
  4315       null "0 : EVEN"
  4316       oddI "n : EVEN ==> Suc n : ODD"
  4317       evenI "n : ODD ==> Suc n : EVEN"
  4318 
  4319 new theorem list "elims" contains an elimination rule for each of the
  4320 recursive sets; inductive definitions now handle disjunctive premises
  4321 correctly (also ZF);
  4322 
  4323 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4324 "mutual_induct" no longer exists - the induction rule is always
  4325 contained in "induct";
  4326 
  4327 
  4328 * HOL/datatype package re-implemented and greatly improved: now
  4329 supports mutually recursive datatypes such as
  4330 
  4331   datatype
  4332     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4333             | SUM ('a aexp) ('a aexp)
  4334             | DIFF ('a aexp) ('a aexp)
  4335             | NUM 'a
  4336   and
  4337     'a bexp = LESS ('a aexp) ('a aexp)
  4338             | AND ('a bexp) ('a bexp)
  4339             | OR ('a bexp) ('a bexp)
  4340 
  4341 as well as indirectly recursive datatypes such as
  4342 
  4343   datatype
  4344     ('a, 'b) term = Var 'a
  4345                   | App 'b ((('a, 'b) term) list)
  4346 
  4347 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4348 induction on mutually / indirectly recursive datatypes.
  4349 
  4350 Primrec equations are now stored in theory and can be accessed via
  4351 <function_name>.simps.
  4352 
  4353 INCOMPATIBILITIES:
  4354 
  4355   - Theories using datatypes must now have theory Datatype as an
  4356     ancestor.
  4357   - The specific <typename>.induct_tac no longer exists - use the
  4358     generic induct_tac instead.
  4359   - natE has been renamed to nat.exhaust - use exhaust_tac
  4360     instead of res_inst_tac ... natE. Note that the variable
  4361     names in nat.exhaust differ from the names in natE, this
  4362     may cause some "fragile" proofs to fail.
  4363   - The theorems split_<typename>_case and split_<typename>_case_asm
  4364     have been renamed to <typename>.split and <typename>.split_asm.
  4365   - Since default sorts of type variables are now handled correctly,
  4366     some datatype definitions may have to be annotated with explicit
  4367     sort constraints.
  4368   - Primrec definitions no longer require function name and type
  4369     of recursive argument.
  4370 
  4371 Consider using isatool fixdatatype to adapt your theories and proof
  4372 scripts to the new package (backup your sources first!).
  4373 
  4374 
  4375 * HOL/record package: considerably improved implementation; now
  4376 includes concrete syntax for record types, terms, updates; theorems
  4377 for surjective pairing and splitting !!-bound record variables; proof
  4378 support is as follows:
  4379 
  4380   1) standard conversions (selectors or updates applied to record
  4381 constructor terms) are part of the standard simpset;
  4382 
  4383   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4384 made part of standard simpset and claset via addIffs;
  4385 
  4386   3) a tactic for record field splitting (record_split_tac) is part of
  4387 the standard claset (addSWrapper);
  4388 
  4389 To get a better idea about these rules you may retrieve them via
  4390 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4391 the name of your record type.
  4392 
  4393 The split tactic 3) conceptually simplifies by the following rule:
  4394 
  4395   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4396 
  4397 Thus any record variable that is bound by meta-all will automatically
  4398 blow up into some record constructor term, consequently the
  4399 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4400 solve record problems automatically.
  4401 
  4402 
  4403 * reorganized the main HOL image: HOL/Integ and String loaded by
  4404 default; theory Main includes everything;
  4405 
  4406 * automatic simplification of integer sums and comparisons, using cancellation;
  4407 
  4408 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4409 
  4410 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4411 
  4412 * many new identities for unions, intersections, set difference, etc.;
  4413 
  4414 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4415 called split_if, split_split, split_sum_case and split_nat_case (to go
  4416 with add/delsplits);
  4417 
  4418 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4419 (?x::unit) = (); this is made part of the default simpset, which COULD
  4420 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4421 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4422 unit_abs_eta_conv is added in order to counter the effect of
  4423 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4424 %u.f();
  4425 
  4426 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4427 makes more sense);
  4428 
  4429 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4430   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4431   disjointness reasoning but breaking a few old proofs.
  4432 
  4433 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4434 to 'converse' from 'inverse' (for compatibility with ZF and some
  4435 literature);
  4436 
  4437 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4438 the well-founded relation;
  4439 
  4440 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4441     Compl A.  The "Compl" syntax remains available as input syntax for this
  4442     release ONLY.
  4443 
  4444 * HOL/Update: new theory of function updates:
  4445     f(a:=b) == %x. if x=a then b else f x
  4446 may also be iterated as in f(a:=b,c:=d,...);
  4447 
  4448 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4449 
  4450 * HOL/List:
  4451   - new function list_update written xs[i:=v] that updates the i-th
  4452     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4453   - new function `upt' written [i..j(] which generates the list
  4454     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4455     bound write [i..j], which is a shorthand for [i..j+1(].
  4456   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4457 
  4458 * HOL/Arith:
  4459   - removed 'pred' (predecessor) function;
  4460   - generalized some theorems about n-1;
  4461   - many new laws about "div" and "mod";
  4462   - new laws about greatest common divisors (see theory ex/Primes);
  4463 
  4464 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4465 instead of "inverse";
  4466 
  4467 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4468   of the multiset ordering;
  4469 
  4470 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4471   (not included by default);
  4472 
  4473 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4474 
  4475 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4476   programs, i.e. different program variables may have different types.
  4477 
  4478 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4479   [previously, this check worked only if the rewrite rule was unconditional]
  4480   Now rew can involve either definitions or equalities (either == or =).
  4481 
  4482 
  4483 *** ZF ***
  4484 
  4485 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4486   only the theorems proved on ZF.ML;
  4487 
  4488 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4489   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4490   disjointness reasoning but breaking a few old proofs.
  4491 
  4492 * ZF/Update: new theory of function updates
  4493     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4494   may also be iterated as in f(a:=b,c:=d,...);
  4495 
  4496 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4497 
  4498 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4499   [previously, this check worked only if the rewrite rule was unconditional]
  4500   Now rew can involve either definitions or equalities (either == or =).
  4501 
  4502 * case_tac provided for compatibility with HOL
  4503     (like the old excluded_middle_tac, but with subgoals swapped)
  4504 
  4505 
  4506 *** Internal programming interfaces ***
  4507 
  4508 * Pure: several new basic modules made available for general use, see
  4509 also src/Pure/README;
  4510 
  4511 * improved the theory data mechanism to support encapsulation (data
  4512 kind name replaced by private Object.kind, acting as authorization
  4513 key); new type-safe user interface via functor TheoryDataFun; generic
  4514 print_data function becomes basically useless;
  4515 
  4516 * removed global_names compatibility flag -- all theory declarations
  4517 are qualified by default;
  4518 
  4519 * module Pure/Syntax now offers quote / antiquote translation
  4520 functions (useful for Hoare logic etc. with implicit dependencies);
  4521 see HOL/ex/Antiquote for an example use;
  4522 
  4523 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4524 cterm -> thm;
  4525 
  4526 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4527 subgoal;
  4528 
  4529 * Display.print_goals function moved to Locale.print_goals;
  4530 
  4531 * standard print function for goals supports current_goals_markers
  4532 variable for marking begin of proof, end of proof, start of goal; the
  4533 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4534 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4535 for example;
  4536 
  4537 
  4538 
  4539 New in Isabelle98 (January 1998)
  4540 --------------------------------
  4541 
  4542 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4543 
  4544 * changed lexical syntax of terms / types: dots made part of long
  4545 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4546 
  4547 * simpset (and claset) reference variable replaced by functions
  4548 simpset / simpset_ref;
  4549 
  4550 * no longer supports theory aliases (via merge) and non-trivial
  4551 implicit merge of thms' signatures;
  4552 
  4553 * most internal names of constants changed due to qualified names;
  4554 
  4555 * changed Pure/Sequence interface (see Pure/seq.ML);
  4556 
  4557 
  4558 *** General Changes ***
  4559 
  4560 * hierachically structured name spaces (for consts, types, axms, thms
  4561 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4562 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4563 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4564 long_names for fully qualified output names; NOTE: ML programs
  4565 (special tactics, packages etc.) referring to internal names may have
  4566 to be adapted to cope with fully qualified names; in case of severe
  4567 backward campatibility problems try setting 'global_names' at compile
  4568 time to have enrything declared within a flat name space; one may also
  4569 fine tune name declarations in theories via the 'global' and 'local'
  4570 section;
  4571 
  4572 * reimplemented the implicit simpset and claset using the new anytype
  4573 data filed in signatures; references simpset:simpset ref etc. are
  4574 replaced by functions simpset:unit->simpset and
  4575 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4576 to patch your ML files accordingly;
  4577 
  4578 * HTML output now includes theory graph data for display with Java
  4579 applet or isatool browser; data generated automatically via isatool
  4580 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4581 
  4582 * defs may now be conditional; improved rewrite_goals_tac to handle
  4583 conditional equations;
  4584 
  4585 * defs now admits additional type arguments, using TYPE('a) syntax;
  4586 
  4587 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4588 creates a new theory node; implicit merge of thms' signatures is
  4589 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4590 transfer:theory->thm->thm in (rare) cases;
  4591 
  4592 * improved handling of draft signatures / theories; draft thms (and
  4593 ctyps, cterms) are automatically promoted to real ones;
  4594 
  4595 * slightly changed interfaces for oracles: admit many per theory, named
  4596 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4597 
  4598 * print_goals: optional output of const types (set show_consts and
  4599 show_types);
  4600 
  4601 * improved output of warnings (###) and errors (***);
  4602 
  4603 * subgoal_tac displays a warning if the new subgoal has type variables;
  4604 
  4605 * removed old README and Makefiles;
  4606 
  4607 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4608 
  4609 * removed obsolete init_pps and init_database;
  4610 
  4611 * deleted the obsolete tactical STATE, which was declared by
  4612     fun STATE tacfun st = tacfun st st;
  4613 
  4614 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4615 (which abbreviates $HOME);
  4616 
  4617 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4618 use isatool fixseq to adapt your ML programs (this works for fully
  4619 qualified references to the Sequence structure only!);
  4620 
  4621 * use_thy no longer requires writable current directory; it always
  4622 reloads .ML *and* .thy file, if either one is out of date;
  4623 
  4624 
  4625 *** Classical Reasoner ***
  4626 
  4627 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4628 tactics that use classical reasoning to simplify a subgoal without
  4629 splitting it into several subgoals;
  4630 
  4631 * Safe_tac: like safe_tac but uses the default claset;
  4632 
  4633 
  4634 *** Simplifier ***
  4635 
  4636 * added simplification meta rules:
  4637     (asm_)(full_)simplify: simpset -> thm -> thm;
  4638 
  4639 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4640 logics (again);
  4641 
  4642 * added prems argument to simplification procedures;
  4643 
  4644 * HOL, FOL, ZF: added infix function `addsplits':
  4645   instead of `<simpset> setloop (split_tac <thms>)'
  4646   you can simply write `<simpset> addsplits <thms>'
  4647 
  4648 
  4649 *** Syntax ***
  4650 
  4651 * TYPE('a) syntax for type reflection terms;
  4652 
  4653 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4654 
  4655 * pretty printer: changed order of mixfix annotation preference (again!);
  4656 
  4657 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4658 
  4659 
  4660 *** HOL ***
  4661 
  4662 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4663   with `addloop' of the simplifier to faciliate case splitting in premises.
  4664 
  4665 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4666 
  4667 * HOL/Auth: new protocol proofs including some for the Internet
  4668   protocol TLS;
  4669 
  4670 * HOL/Map: new theory of `maps' a la VDM;
  4671 
  4672 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4673 cancelling out common nat summands from =, <, <= (in)equalities, or
  4674 differences; simplification procedures nat_cancel_factor for
  4675 cancelling common factor from =, <, <= (in)equalities over natural
  4676 sums; nat_cancel contains both kinds of procedures, it is installed by
  4677 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4678 
  4679 * HOL/simplifier: terms of the form
  4680   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4681   are rewritten to
  4682   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4683   and those of the form
  4684   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4685   are rewritten to
  4686   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4687 
  4688 * HOL/datatype
  4689   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4690 
  4691   P(t_case f1 ... fn x) =
  4692      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4693         ...
  4694        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4695      )
  4696 
  4697   and a theorem `split_t_case_asm' of the form
  4698 
  4699   P(t_case f1 ... fn x) =
  4700     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4701         ...
  4702        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4703      )
  4704   which can be added to a simpset via `addsplits'. The existing theorems
  4705   expand_list_case and expand_option_case have been renamed to
  4706   split_list_case and split_option_case.
  4707 
  4708 * HOL/Arithmetic:
  4709   - `pred n' is automatically converted to `n-1'.
  4710     Users are strongly encouraged not to use `pred' any longer,
  4711     because it will disappear altogether at some point.
  4712   - Users are strongly encouraged to write "0 < n" rather than
  4713     "n ~= 0". Theorems and proof tools have been modified towards this
  4714     `standard'.
  4715 
  4716 * HOL/Lists:
  4717   the function "set_of_list" has been renamed "set" (and its theorems too);
  4718   the function "nth" now takes its arguments in the reverse order and
  4719   has acquired the infix notation "!" as in "xs!n".
  4720 
  4721 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4722 
  4723 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4724   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4725 
  4726 * HOL/record: extensible records with schematic structural subtyping
  4727 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4728 still lacks various theorems and concrete record syntax;
  4729 
  4730 
  4731 *** HOLCF ***
  4732 
  4733 * removed "axioms" and "generated by" sections;
  4734 
  4735 * replaced "ops" section by extended "consts" section, which is capable of
  4736   handling the continuous function space "->" directly;
  4737 
  4738 * domain package:
  4739   . proves theorems immediately and stores them in the theory,
  4740   . creates hierachical name space,
  4741   . now uses normal mixfix annotations (instead of cinfix...),
  4742   . minor changes to some names and values (for consistency),
  4743   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4744   . separator between mutual domain defs: changed "," to "and",
  4745   . improved handling of sort constraints;  now they have to
  4746     appear on the left-hand side of the equations only;
  4747 
  4748 * fixed LAM <x,y,zs>.b syntax;
  4749 
  4750 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4751 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4752 
  4753 
  4754 *** FOL and ZF ***
  4755 
  4756 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4757   with `addloop' of the simplifier to faciliate case splitting in premises.
  4758 
  4759 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4760 in HOL, they strip ALL and --> from proved theorems;
  4761 
  4762 
  4763 
  4764 New in Isabelle94-8 (May 1997)
  4765 ------------------------------
  4766 
  4767 *** General Changes ***
  4768 
  4769 * new utilities to build / run / maintain Isabelle etc. (in parts
  4770 still somewhat experimental); old Makefiles etc. still functional;
  4771 
  4772 * new 'Isabelle System Manual';
  4773 
  4774 * INSTALL text, together with ./configure and ./build scripts;
  4775 
  4776 * reimplemented type inference for greater efficiency, better error
  4777 messages and clean internal interface;
  4778 
  4779 * prlim command for dealing with lots of subgoals (an easier way of
  4780 setting goals_limit);
  4781 
  4782 
  4783 *** Syntax ***
  4784 
  4785 * supports alternative (named) syntax tables (parser and pretty
  4786 printer); internal interface is provided by add_modesyntax(_i);
  4787 
  4788 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4789 be used in conjunction with the Isabelle symbol font; uses the
  4790 "symbols" syntax table;
  4791 
  4792 * added token_translation interface (may translate name tokens in
  4793 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4794 the current print_mode); IMPORTANT: user print translation functions
  4795 are responsible for marking newly introduced bounds
  4796 (Syntax.mark_boundT);
  4797 
  4798 * token translations for modes "xterm" and "xterm_color" that display
  4799 names in bold, underline etc. or colors (which requires a color
  4800 version of xterm);
  4801 
  4802 * infixes may now be declared with names independent of their syntax;
  4803 
  4804 * added typed_print_translation (like print_translation, but may
  4805 access type of constant);
  4806 
  4807 
  4808 *** Classical Reasoner ***
  4809 
  4810 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4811 some limitations.  Blast_tac...
  4812   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4813   + ignores elimination rules that don't have the correct format
  4814         (the conclusion MUST be a formula variable)
  4815   + ignores types, which can make HOL proofs fail
  4816   + rules must not require higher-order unification, e.g. apply_type in ZF
  4817     [message "Function Var's argument not a bound variable" relates to this]
  4818   + its proof strategy is more general but can actually be slower
  4819 
  4820 * substitution with equality assumptions no longer permutes other
  4821 assumptions;
  4822 
  4823 * minor changes in semantics of addafter (now called addaltern); renamed
  4824 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4825 (and access functions for it);
  4826 
  4827 * improved combination of classical reasoner and simplifier:
  4828   + functions for handling clasimpsets
  4829   + improvement of addss: now the simplifier is called _after_ the
  4830     safe steps.
  4831   + safe variant of addss called addSss: uses safe simplifications
  4832     _during_ the safe steps. It is more complete as it allows multiple
  4833     instantiations of unknowns (e.g. with slow_tac).
  4834 
  4835 *** Simplifier ***
  4836 
  4837 * added interface for simplification procedures (functions that
  4838 produce *proven* rewrite rules on the fly, depending on current
  4839 redex);
  4840 
  4841 * ordering on terms as parameter (used for ordered rewriting);
  4842 
  4843 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4844 
  4845 * the solver is now split into a safe and an unsafe part.
  4846 This should be invisible for the normal user, except that the
  4847 functions setsolver and addsolver have been renamed to setSolver and
  4848 addSolver; added safe_asm_full_simp_tac;
  4849 
  4850 
  4851 *** HOL ***
  4852 
  4853 * a generic induction tactic `induct_tac' which works for all datatypes and
  4854 also for type `nat';
  4855 
  4856 * a generic case distinction tactic `exhaust_tac' which works for all
  4857 datatypes and also for type `nat';
  4858 
  4859 * each datatype comes with a function `size';
  4860 
  4861 * patterns in case expressions allow tuple patterns as arguments to
  4862 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4863 
  4864 * primrec now also works with type nat;
  4865 
  4866 * recdef: a new declaration form, allows general recursive functions to be
  4867 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4868 
  4869 * the constant for negation has been renamed from "not" to "Not" to
  4870 harmonize with FOL, ZF, LK, etc.;
  4871 
  4872 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4873 infinite lists;
  4874 
  4875 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4876 
  4877 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4878 problems in commutative rings, using axiomatic type classes for + and *;
  4879 
  4880 * more examples in HOL/MiniML and HOL/Auth;
  4881 
  4882 * more default rewrite rules for quantifiers, union/intersection;
  4883 
  4884 * a new constant `arbitrary == @x.False';
  4885 
  4886 * HOLCF/IOA replaces old HOL/IOA;
  4887 
  4888 * HOLCF changes: derived all rules and arities
  4889   + axiomatic type classes instead of classes
  4890   + typedef instead of faking type definitions
  4891   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4892   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4893   + eliminated the types void, one, tr
  4894   + use unit lift and bool lift (with translations) instead of one and tr
  4895   + eliminated blift from Lift3.thy (use Def instead of blift)
  4896   all eliminated rules are derived as theorems --> no visible changes ;
  4897 
  4898 
  4899 *** ZF ***
  4900 
  4901 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4902 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4903 as ZF_cs addSIs [equalityI];
  4904 
  4905 
  4906 
  4907 New in Isabelle94-7 (November 96)
  4908 ---------------------------------
  4909 
  4910 * allowing negative levels (as offsets) in prlev and choplev;
  4911 
  4912 * super-linear speedup for large simplifications;
  4913 
  4914 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4915 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4916 FAIL); can suppress it using the command Delsimps (ex_simps @
  4917 all_simps); De Morgan laws are also now included, by default;
  4918 
  4919 * improved printing of ==>  :  ~:
  4920 
  4921 * new object-logic "Sequents" adds linear logic, while replacing LK
  4922 and Modal (thanks to Sara Kalvala);
  4923 
  4924 * HOL/Auth: correctness proofs for authentication protocols;
  4925 
  4926 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4927 examples on HOL/Auth);
  4928 
  4929 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4930 the rewriter and classical reasoner simultaneously;
  4931 
  4932 * function uresult no longer returns theorems in "standard" format;
  4933 regain previous version by: val uresult = standard o uresult;
  4934 
  4935 
  4936 
  4937 New in Isabelle94-6
  4938 -------------------
  4939 
  4940 * oracles -- these establish an interface between Isabelle and trusted
  4941 external reasoners, which may deliver results as theorems;
  4942 
  4943 * proof objects (in particular record all uses of oracles);
  4944 
  4945 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4946 
  4947 * "constdefs" section in theory files;
  4948 
  4949 * "primrec" section (HOL) no longer requires names;
  4950 
  4951 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4952 
  4953 
  4954 
  4955 New in Isabelle94-5
  4956 -------------------
  4957 
  4958 * reduced space requirements;
  4959 
  4960 * automatic HTML generation from theories;
  4961 
  4962 * theory files no longer require "..." (quotes) around most types;
  4963 
  4964 * new examples, including two proofs of the Church-Rosser theorem;
  4965 
  4966 * non-curried (1994) version of HOL is no longer distributed;
  4967 
  4968 
  4969 
  4970 New in Isabelle94-4
  4971 -------------------
  4972 
  4973 * greatly reduced space requirements;
  4974 
  4975 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4976 
  4977 * searchable theorem database (see the section "Retrieving theorems" on
  4978 page 8 of the Reference Manual);
  4979 
  4980 * new examples, including Grabczewski's monumental case study of the
  4981 Axiom of Choice;
  4982 
  4983 * The previous version of HOL renamed to Old_HOL;
  4984 
  4985 * The new version of HOL (previously called CHOL) uses a curried syntax
  4986 for functions.  Application looks like f a b instead of f(a,b);
  4987 
  4988 * Mutually recursive inductive definitions finally work in HOL;
  4989 
  4990 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4991 translates to the operator "split";
  4992 
  4993 
  4994 
  4995 New in Isabelle94-3
  4996 -------------------
  4997 
  4998 * new infix operator, addss, allowing the classical reasoner to
  4999 perform simplification at each step of its search.  Example:
  5000         fast_tac (cs addss ss)
  5001 
  5002 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5003 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5004 look like (a,b) instead of <a,b>;
  5005 
  5006 * PLEASE NOTE: CHOL will eventually replace HOL!
  5007 
  5008 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5009 It translates to the operator "split".  A new theory of integers is available;
  5010 
  5011 * In ZF, integer numerals now denote two's-complement binary integers.
  5012 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5013 
  5014 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5015 of the Axiom of Choice;
  5016 
  5017 
  5018 
  5019 New in Isabelle94-2
  5020 -------------------
  5021 
  5022 * Significantly faster resolution;
  5023 
  5024 * the different sections in a .thy file can now be mixed and repeated
  5025 freely;
  5026 
  5027 * Database of theorems for FOL, HOL and ZF.  New
  5028 commands including qed, qed_goal and bind_thm store theorems in the database.
  5029 
  5030 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5031 a given theory (thms_of), or find out what theory a theorem was proved in
  5032 (theory_of_thm);
  5033 
  5034 * Bugs fixed in the inductive definition and datatype packages;
  5035 
  5036 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5037 and HOL_dup_cs obsolete;
  5038 
  5039 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5040 have been removed;
  5041 
  5042 * Simpler definition of function space in ZF;
  5043 
  5044 * new results about cardinal and ordinal arithmetic in ZF;
  5045 
  5046 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5047 types;
  5048 
  5049 :mode=text:wrap=hard:maxLineLen=72:
  5050 $Id$