NEWS
author paulson
Wed Nov 28 16:26:03 2007 +0100 (2007-11-28)
changeset 25492 4cc7976948ac
parent 25464 0ca80ce89001
child 25502 9200b36280c0
permissions -rw-r--r--
Chained theorems are no longer mentioned in metis calls and (if used) they prevent the
output of a structured proof.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** HOL ***
     8 
     9 * Constant "card" now with authentic syntax.
    10 
    11 
    12 
    13 New in Isabelle2007 (November 2007)
    14 -----------------------------------
    15 
    16 *** General ***
    17 
    18 * More uniform information about legacy features, notably a
    19 warning/error of "Legacy feature: ...", depending on the state of the
    20 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
    21 legacy features will disappear eventually.
    22 
    23 * Theory syntax: the header format ``theory A = B + C:'' has been
    24 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    25 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    26 
    27 * Theory syntax: the old non-Isar theory file format has been
    28 discontinued altogether.  Note that ML proof scripts may still be used
    29 with Isar theories; migration is usually quite simple with the ML
    30 function use_legacy_bindings.  INCOMPATIBILITY.
    31 
    32 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    33 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    34 quotes.
    35 
    36 * Theory loader: be more serious about observing the static theory
    37 header specifications (including optional directories), but not the
    38 accidental file locations of previously successful loads.  The strict
    39 update policy of former update_thy is now already performed by
    40 use_thy, so the former has been removed; use_thys updates several
    41 theories simultaneously, just as 'imports' within a theory header
    42 specification, but without merging the results.  Potential
    43 INCOMPATIBILITY: may need to refine theory headers and commands
    44 ROOT.ML which depend on load order.
    45 
    46 * Theory loader: optional support for content-based file
    47 identification, instead of the traditional scheme of full physical
    48 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
    49 (cf. the system manual).  The new scheme allows to work with
    50 non-finished theories in persistent session images, such that source
    51 files may be moved later on without requiring reloads.
    52 
    53 * Theory loader: old-style ML proof scripts being *attached* to a thy
    54 file (with the same base name as the theory) are considered a legacy
    55 feature, which will disappear eventually. Even now, the theory loader
    56 no longer maintains dependencies on such files.
    57 
    58 * Syntax: the scope for resolving ambiguities via type-inference is
    59 now limited to individual terms, instead of whole simultaneous
    60 specifications as before. This greatly reduces the complexity of the
    61 syntax module and improves flexibility by separating parsing and
    62 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
    63 'fixes' etc.) are required in rare situations.
    64 
    65 * Syntax: constants introduced by new-style packages ('definition',
    66 'abbreviation' etc.) are passed through the syntax module in
    67 ``authentic mode''. This means that associated mixfix annotations
    68 really stick to such constants, independently of potential name space
    69 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
    70 trees are represented slightly differently, may need to adapt syntax
    71 translations accordingly. Use CONST marker in 'translations' and
    72 @{const_syntax} antiquotation in 'parse_translation' etc.
    73 
    74 * Legacy goal package: reduced interface to the bare minimum required
    75 to keep existing proof scripts running.  Most other user-level
    76 functions are now part of the OldGoals structure, which is *not* open
    77 by default (consider isatool expandshort before open OldGoals).
    78 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    79 these tend to cause confusion about the actual goal (!) context being
    80 used here, which is not necessarily the same as the_context().
    81 
    82 * Command 'find_theorems': supports "*" wild-card in "name:"
    83 criterion; "with_dups" option.  Certain ProofGeneral versions might
    84 support a specific search form (see ProofGeneral/CHANGES).
    85 
    86 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    87 by default, which means that "prems" (and also "fixed variables") are
    88 suppressed from proof state output.  Note that the ProofGeneral
    89 settings mechanism allows to change and save options persistently, but
    90 older versions of Isabelle will fail to start up if a negative prems
    91 limit is imposed.
    92 
    93 * Local theory targets may be specified by non-nested blocks of
    94 ``context/locale/class ... begin'' followed by ``end''.  The body may
    95 contain definitions, theorems etc., including any derived mechanism
    96 that has been implemented on top of these primitives.  This concept
    97 generalizes the existing ``theorem (in ...)'' towards more versatility
    98 and scalability.
    99 
   100 * Proof General interface: proper undo of final 'end' command;
   101 discontinued Isabelle/classic mode (ML proof scripts).
   102 
   103 
   104 *** Document preparation ***
   105 
   106 * Added antiquotation @{theory name} which prints the given name,
   107 after checking that it refers to a valid ancestor theory in the
   108 current context.
   109 
   110 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   111 check the given source text as ML type/structure, printing verbatim.
   112 
   113 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   114 "c args == rhs" given in the current context.  (Any number of
   115 arguments may be given on the LHS.)
   116 
   117 
   118 *** Pure ***
   119 
   120 * The 'class' package offers a combination of axclass and locale to
   121 achieve Haskell-like type classes in Isabelle.  Definitions and
   122 theorems within a class context produce both relative results (with
   123 implicit parameters according to the locale context), and polymorphic
   124 constants with qualified polymorphism (according to the class
   125 context).  Within the body context of a 'class' target, a separate
   126 syntax layer ("user space type system") takes care of converting
   127 between global polymorphic consts and internal locale representation.
   128 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   129 "isatool doc classes" provides a tutorial.
   130 
   131 * Generic code generator framework allows to generate executable
   132 code for ML and Haskell (including Isabelle classes).  A short usage
   133 sketch:
   134 
   135     internal compilation:
   136         export_code <list of constants (term syntax)> in SML
   137     writing SML code to a file:
   138         export_code <list of constants (term syntax)> in SML <filename>
   139     writing OCaml code to a file:
   140         export_code <list of constants (term syntax)> in OCaml <filename>
   141     writing Haskell code to a bunch of files:
   142         export_code <list of constants (term syntax)> in Haskell <filename>
   143 
   144     evaluating closed propositions to True/False using code generation:
   145         method ``eval''
   146 
   147 Reasonable default setup of framework in HOL.
   148 
   149 Theorem attributs for selecting and transforming function equations theorems:
   150 
   151     [code fun]:        select a theorem as function equation for a specific constant
   152     [code fun del]:    deselect a theorem as function equation for a specific constant
   153     [code inline]:     select an equation theorem for unfolding (inlining) in place
   154     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   155 
   156 User-defined serializations (target in {SML, OCaml, Haskell}):
   157 
   158     code_const <and-list of constants (term syntax)>
   159       {(target) <and-list of const target syntax>}+
   160 
   161     code_type <and-list of type constructors>
   162       {(target) <and-list of type target syntax>}+
   163 
   164     code_instance <and-list of instances>
   165       {(target)}+
   166         where instance ::= <type constructor> :: <class>
   167 
   168     code_class <and_list of classes>
   169       {(target) <and-list of class target syntax>}+
   170         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   171 
   172 code_instance and code_class only are effective to target Haskell.
   173 
   174 For example usage see src/HOL/ex/Codegenerator.thy and
   175 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   176 generation from Isabelle/HOL theories is available via "isatool doc
   177 codegen".
   178 
   179 * Code generator: consts in 'consts_code' Isar commands are now
   180 referred to by usual term syntax (including optional type
   181 annotations).
   182 
   183 * Command 'no_translations' removes translation rules from theory
   184 syntax.
   185 
   186 * Overloaded definitions are now actually checked for acyclic
   187 dependencies.  The overloading scheme is slightly more general than
   188 that of Haskell98, although Isabelle does not demand an exact
   189 correspondence to type class and instance declarations.
   190 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   191 exotic versions of overloading -- at the discretion of the user!
   192 
   193 Polymorphic constants are represented via type arguments, i.e. the
   194 instantiation that matches an instance against the most general
   195 declaration given in the signature.  For example, with the declaration
   196 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   197 as c(nat).  Overloading is essentially simultaneous structural
   198 recursion over such type arguments.  Incomplete specification patterns
   199 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   200 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   201 Command 'print_theory' outputs the normalized system of recursive
   202 equations, see section "definitions".
   203 
   204 * Configuration options are maintained within the theory or proof
   205 context (with name and type bool/int/string), providing a very simple
   206 interface to a poor-man's version of general context data.  Tools may
   207 declare options in ML (e.g. using Attrib.config_int) and then refer to
   208 these values using Config.get etc.  Users may change options via an
   209 associated attribute of the same name.  This form of context
   210 declaration works particularly well with commands 'declare' or
   211 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   212 very easy to avoid global references, which would not observe Isar
   213 toplevel undo/redo and fail to work with multithreading.
   214 
   215 Various global ML references of Pure and HOL have been turned into
   216 configuration options:
   217 
   218   Unify.search_bound		unify_search_bound
   219   Unify.trace_bound		unify_trace_bound
   220   Unify.trace_simp		unify_trace_simp
   221   Unify.trace_types		unify_trace_types
   222   Simplifier.simp_depth_limit	simp_depth_limit
   223   Blast.depth_limit		blast_depth_limit
   224   DatatypeProp.dtK		datatype_distinctness_limit
   225   fast_arith_neq_limit  	fast_arith_neq_limit
   226   fast_arith_split_limit	fast_arith_split_limit
   227 
   228 * Named collections of theorems may be easily installed as context
   229 data using the functor NamedThmsFun (see also
   230 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   231 attributes; there is also a toplevel print command.  This facility is
   232 just a common case of general context data, which is the preferred way
   233 for anything more complex than just a list of facts in canonical
   234 order.
   235 
   236 * Isar: command 'declaration' augments a local theory by generic
   237 declaration functions written in ML.  This enables arbitrary content
   238 being added to the context, depending on a morphism that tells the
   239 difference of the original declaration context wrt. the application
   240 context encountered later on.
   241 
   242 * Isar: proper interfaces for simplification procedures.  Command
   243 'simproc_setup' declares named simprocs (with match patterns, and body
   244 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   245 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   246 
   247 * Isar: an extra pair of brackets around attribute declarations
   248 abbreviates a theorem reference involving an internal dummy fact,
   249 which will be ignored later --- only the effect of the attribute on
   250 the background context will persist.  This form of in-place
   251 declarations is particularly useful with commands like 'declare' and
   252 'using', for example ``have A using [[simproc a]] by simp''.
   253 
   254 * Isar: method "assumption" (and implicit closing of subproofs) now
   255 takes simple non-atomic goal assumptions into account: after applying
   256 an assumption as a rule the resulting subgoals are solved by atomic
   257 assumption steps.  This is particularly useful to finish 'obtain'
   258 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   259 without referring to the original premise "!!x. P x ==> thesis" in the
   260 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   261 more permissive.
   262 
   263 * Isar: implicit use of prems from the Isar proof context is
   264 considered a legacy feature.  Common applications like ``have A .''
   265 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   266 referencing facts explicitly here improves readability and
   267 maintainability of proof texts.
   268 
   269 * Isar: improper proof element 'guess' is like 'obtain', but derives
   270 the obtained context from the course of reasoning!  For example:
   271 
   272   assume "EX x y. A x & B y"   -- "any previous fact"
   273   then guess x and y by clarify
   274 
   275 This technique is potentially adventurous, depending on the facts and
   276 proof tools being involved here.
   277 
   278 * Isar: known facts from the proof context may be specified as literal
   279 propositions, using ASCII back-quote syntax.  This works wherever
   280 named facts used to be allowed so far, in proof commands, proof
   281 methods, attributes etc.  Literal facts are retrieved from the context
   282 according to unification of type and term parameters.  For example,
   283 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   284 theorems in the current context, then these are valid literal facts:
   285 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   286 
   287 There is also a proof method "fact" which does the same composition
   288 for explicit goal states, e.g. the following proof texts coincide with
   289 certain special cases of literal facts:
   290 
   291   have "A" by fact                 ==  note `A`
   292   have "A ==> B" by fact           ==  note `A ==> B`
   293   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   294   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   295 
   296 * Isar: ":" (colon) is no longer a symbolic identifier character in
   297 outer syntax.  Thus symbolic identifiers may be used without
   298 additional white space in declarations like this: ``assume *: A''.
   299 
   300 * Isar: 'print_facts' prints all local facts of the current context,
   301 both named and unnamed ones.
   302 
   303 * Isar: 'def' now admits simultaneous definitions, e.g.:
   304 
   305   def x == "t" and y == "u"
   306 
   307 * Isar: added command 'unfolding', which is structurally similar to
   308 'using', but affects both the goal state and facts by unfolding given
   309 rewrite rules.  Thus many occurrences of the 'unfold' method or
   310 'unfolded' attribute may be replaced by first-class proof text.
   311 
   312 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   313 and command 'unfolding' now all support object-level equalities
   314 (potentially conditional).  The underlying notion of rewrite rule is
   315 analogous to the 'rule_format' attribute, but *not* that of the
   316 Simplifier (which is usually more generous).
   317 
   318 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   319 premises of a theorem by n. Useful in conjunction with drule.
   320 
   321 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   322 method expression within a sandbox consisting of the first N
   323 sub-goals, which need to exist.  For example, ``simp_all [3]''
   324 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   325 simplifies all new goals that emerge from applying rule foo to the
   326 originally first one.
   327 
   328 * Isar: schematic goals are no longer restricted to higher-order
   329 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   330 expected.
   331 
   332 * Isar: the conclusion of a long theorem statement is now either
   333 'shows' (a simultaneous conjunction, as before), or 'obtains'
   334 (essentially a disjunction of cases with local parameters and
   335 assumptions).  The latter allows to express general elimination rules
   336 adequately; in this notation common elimination rules look like this:
   337 
   338   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   339     assumes "EX x. P x"
   340     obtains x where "P x"
   341 
   342   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   343     assumes "A & B"
   344     obtains A and B
   345 
   346   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   347     assumes "A | B"
   348     obtains
   349       A
   350     | B
   351 
   352 The subsequent classical rules even refer to the formal "thesis"
   353 explicitly:
   354 
   355   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   356     obtains "~ thesis"
   357 
   358   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   359     obtains "thesis ==> something"
   360 
   361 The actual proof of an 'obtains' statement is analogous to that of the
   362 Isar proof element 'obtain', only that there may be several cases.
   363 Optional case names may be specified in parentheses; these will be
   364 available both in the present proof and as annotations in the
   365 resulting rule, for later use with the 'cases' method (cf. attribute
   366 case_names).
   367 
   368 * Isar: the assumptions of a long theorem statement are available as
   369 "assms" fact in the proof context.  This is more appropriate than the
   370 (historical) "prems", which refers to all assumptions of the current
   371 context, including those from the target locale, proof body etc.
   372 
   373 * Isar: 'print_statement' prints theorems from the current theory or
   374 proof context in long statement form, according to the syntax of a
   375 top-level lemma.
   376 
   377 * Isar: 'obtain' takes an optional case name for the local context
   378 introduction rule (default "that").
   379 
   380 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   381 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   382 to occur.
   383 
   384 * Pure: syntax "CONST name" produces a fully internalized constant
   385 according to the current context.  This is particularly useful for
   386 syntax translations that should refer to internal constant
   387 representations independently of name spaces.
   388 
   389 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   390 instead of "FOO ". This allows multiple binder declarations to coexist
   391 in the same context.  INCOMPATIBILITY.
   392 
   393 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   394 primitive that also works in a locale context (both for constants and
   395 fixed variables). Type declaration and internal syntactic representation
   396 of given constants retrieved from the context. Likewise, the
   397 'no_notation' command allows to remove given syntax annotations from the
   398 current context.
   399 
   400 * Isar/locales: new derived specification elements 'axiomatization',
   401 'definition', 'abbreviation', which support type-inference, admit
   402 object-level specifications (equality, equivalence).  See also the
   403 isar-ref manual.  Examples:
   404 
   405   axiomatization
   406     eq  (infix "===" 50) where
   407     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   408 
   409   definition "f x y = x + y + 1"
   410   definition g where "g x = f x x"
   411 
   412   abbreviation
   413     neq  (infix "=!=" 50) where
   414     "x =!= y == ~ (x === y)"
   415 
   416 These specifications may be also used in a locale context.  Then the
   417 constants being introduced depend on certain fixed parameters, and the
   418 constant name is qualified by the locale base name.  An internal
   419 abbreviation takes care for convenient input and output, making the
   420 parameters implicit and using the original short name.  See also
   421 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   422 entities from a monomorphic theory.
   423 
   424 Presently, abbreviations are only available 'in' a target locale, but
   425 not inherited by general import expressions.  Also note that
   426 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   427 'translations' in common applications.  The "no_abbrevs" print mode
   428 prevents folding of abbreviations in term output.
   429 
   430 Concrete syntax is attached to specified constants in internal form,
   431 independently of name spaces.  The parse tree representation is
   432 slightly different -- use 'notation' instead of raw 'syntax', and
   433 'translations' with explicit "CONST" markup to accommodate this.
   434 
   435 * Pure/Isar: unified syntax for new-style specification mechanisms
   436 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   437 full type inference and dummy patterns ("_").  For example:
   438 
   439   definition "K x _ = x"
   440 
   441   inductive conj for A B
   442   where "A ==> B ==> conj A B"
   443 
   444 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   445 the current context.  Print mode "no_abbrevs" prevents inversion of
   446 abbreviations on output.
   447 
   448 * Isar/locales: improved parameter handling: use of locales "var" and
   449 "struct" no longer necessary; - parameter renamings are no longer
   450 required to be injective.  For example, this allows to define
   451 endomorphisms as locale endom = homom mult mult h.
   452 
   453 * Isar/locales: changed the way locales with predicates are defined.
   454 Instead of accumulating the specification, the imported expression is
   455 now an interpretation.  INCOMPATIBILITY: different normal form of
   456 locale expressions.  In particular, in interpretations of locales with
   457 predicates, goals repesenting already interpreted fragments are not
   458 removed automatically.  Use methods `intro_locales' and
   459 `unfold_locales'; see below.
   460 
   461 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   462 provide backward reasoning on locales predicates.  The methods are
   463 aware of interpretations and discharge corresponding goals.
   464 `intro_locales' is less aggressive then `unfold_locales' and does not
   465 unfold predicates to assumptions.
   466 
   467 * Isar/locales: the order in which locale fragments are accumulated
   468 has changed.  This enables to override declarations from fragments due
   469 to interpretations -- for example, unwanted simp rules.
   470 
   471 * Isar/locales: interpretation in theories and proof contexts has been
   472 extended.  One may now specify (and prove) equations, which are
   473 unfolded in interpreted theorems.  This is useful for replacing
   474 defined concepts (constants depending on locale parameters) by
   475 concepts already existing in the target context.  Example:
   476 
   477   interpretation partial_order ["op <= :: [int, int] => bool"]
   478     where "partial_order.less (op <=) (x::int) y = (x < y)"
   479 
   480 Typically, the constant `partial_order.less' is created by a
   481 definition specification element in the context of locale
   482 partial_order.
   483 
   484 * Method "induct": improved internal context management to support
   485 local fixes and defines on-the-fly. Thus explicit meta-level
   486 connectives !!  and ==> are rarely required anymore in inductive goals
   487 (using object-logic connectives for this purpose has been long
   488 obsolete anyway). Common proof patterns are explained in
   489 src/HOL/Induct/Common_Patterns.thy, see also
   490 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   491 examples.
   492 
   493 * Method "induct": improved handling of simultaneous goals. Instead of
   494 introducing object-level conjunction, the statement is now split into
   495 several conclusions, while the corresponding symbolic cases are nested
   496 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   497 see src/HOL/Induct/Common_Patterns.thy, for example.
   498 
   499 * Method "induct": mutual induction rules are now specified as a list
   500 of rule sharing the same induction cases. HOL packages usually provide
   501 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   502 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   503 mutual induction rules differently, i.e. like this:
   504 
   505   (induct rule: foo_bar.inducts)
   506   (induct set: foo bar)
   507   (induct pred: foo bar)
   508   (induct type: foo bar)
   509 
   510 The ML function ProjectRule.projections turns old-style rules into the
   511 new format.
   512 
   513 * Method "coinduct": dual of induction, see
   514 src/HOL/Library/Coinductive_List.thy for various examples.
   515 
   516 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   517 considered a legacy feature.
   518 
   519 * Attribute "symmetric" produces result with standardized schematic
   520 variables (index 0).  Potential INCOMPATIBILITY.
   521 
   522 * Simplifier: by default the simplifier trace only shows top level
   523 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   524 default. Thus there is less danger of being flooded by the trace. The
   525 trace indicates where parts have been suppressed.
   526   
   527 * Provers/classical: removed obsolete classical version of elim_format
   528 attribute; classical elim/dest rules are now treated uniformly when
   529 manipulating the claset.
   530 
   531 * Provers/classical: stricter checks to ensure that supplied intro,
   532 dest and elim rules are well-formed; dest and elim rules must have at
   533 least one premise.
   534 
   535 * Provers/classical: attributes dest/elim/intro take an optional
   536 weight argument for the rule (just as the Pure versions).  Weights are
   537 ignored by automated tools, but determine the search order of single
   538 rule steps.
   539 
   540 * Syntax: input syntax now supports dummy variable binding "%_. b",
   541 where the body does not mention the bound variable.  Note that dummy
   542 patterns implicitly depend on their context of bounds, which makes
   543 "{_. _}" match any set comprehension as expected.  Potential
   544 INCOMPATIBILITY -- parse translations need to cope with syntactic
   545 constant "_idtdummy" in the binding position.
   546 
   547 * Syntax: removed obsolete syntactic constant "_K" and its associated
   548 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   549 for example "A -> B" => "Pi A (%_. B)".
   550 
   551 * Pure: 'class_deps' command visualizes the subclass relation, using
   552 the graph browser tool.
   553 
   554 * Pure: 'print_theory' now suppresses certain internal declarations by
   555 default; use '!' option for full details.
   556 
   557 
   558 *** HOL ***
   559 
   560 * Method "metis" proves goals by applying the Metis general-purpose
   561 resolution prover (see also http://gilith.com/software/metis/).
   562 Examples are in the directory MetisExamples.  WARNING: the
   563 Isabelle/HOL-Metis integration does not yet work properly with
   564 multi-threading.
   565   
   566 * Command 'sledgehammer' invokes external automatic theorem provers as
   567 background processes.  It generates calls to the "metis" method if
   568 successful. These can be pasted into the proof.  Users do not have to
   569 wait for the automatic provers to return.  WARNING: does not really
   570 work with multi-threading.
   571 
   572 * New "auto_quickcheck" feature tests outermost goal statements for
   573 potential counter-examples.  Controlled by ML references
   574 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   575 5000 milliseconds).  Fails silently if statements is outside of
   576 executable fragment, or any other codgenerator problem occurs.
   577 
   578 * New constant "undefined" with axiom "undefined x = undefined".
   579 
   580 * Added class "HOL.eq", allowing for code generation with polymorphic
   581 equality.
   582 
   583 * Some renaming of class constants due to canonical name prefixing in
   584 the new 'class' package:
   585 
   586     HOL.abs ~> HOL.abs_class.abs
   587     HOL.divide ~> HOL.divide_class.divide
   588     0 ~> HOL.zero_class.zero
   589     1 ~> HOL.one_class.one
   590     op + ~> HOL.plus_class.plus
   591     op - ~> HOL.minus_class.minus
   592     uminus ~> HOL.minus_class.uminus
   593     op * ~> HOL.times_class.times
   594     op < ~> HOL.ord_class.less
   595     op <= > HOL.ord_class.less_eq
   596     Nat.power ~> Power.power_class.power
   597     Nat.size ~> Nat.size_class.size
   598     Numeral.number_of ~> Numeral.number_class.number_of
   599     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   600     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   601     Orderings.min ~> Orderings.ord_class.min
   602     Orderings.max ~> Orderings.ord_class.max
   603     Divides.op div ~> Divides.div_class.div
   604     Divides.op mod ~> Divides.div_class.mod
   605     Divides.op dvd ~> Divides.div_class.dvd
   606 
   607 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   608 
   609 a) User-defined constants using any of the names "plus", "minus",
   610 "times", "less" or "less_eq". The standard syntax translations for
   611 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   612 names.
   613 
   614 b) Variables named "plus", "minus", "times", "less", "less_eq"
   615 INCOMPATIBILITY: use more specific names.
   616 
   617 c) Permutative equations (e.g. "a + b = b + a")
   618 Since the change of names also changes the order of terms, permutative
   619 rewrite rules may get applied in a different order. Experience shows
   620 that this is rarely the case (only two adaptions in the whole Isabelle
   621 distribution).  INCOMPATIBILITY: rewrite proofs
   622 
   623 d) ML code directly refering to constant names
   624 This in general only affects hand-written proof tactics, simprocs and
   625 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   626 Consider using @{const_name} antiquotation.
   627 
   628 * New class "default" with associated constant "default".
   629 
   630 * Function "sgn" is now overloaded and available on int, real, complex
   631 (and other numeric types), using class "sgn".  Two possible defs of
   632 sgn are given as equational assumptions in the classes sgn_if and
   633 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   634 INCOMPATIBILITY.
   635 
   636 * Locale "partial_order" now unified with class "order" (cf. theory
   637 Orderings), added parameter "less".  INCOMPATIBILITY.
   638 
   639 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   640 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   641 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   642 
   643 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   644 changed order of proof goals in instance proofs.
   645 
   646 * The transitivity reasoner for partial and linear orders is set up
   647 for classes "order" and "linorder".  Instances of the reasoner are available
   648 in all contexts importing or interpreting the corresponding locales.
   649 Method "order" invokes the reasoner separately; the reasoner
   650 is also integrated with the Simplifier as a solver.  Diagnostic
   651 command 'print_orders' shows the available instances of the reasoner
   652 in the current context.
   653 
   654 * Localized monotonicity predicate in theory "Orderings"; integrated
   655 lemmas max_of_mono and min_of_mono with this predicate.
   656 INCOMPATIBILITY.
   657 
   658 * Formulation of theorem "dense" changed slightly due to integration
   659 with new class dense_linear_order.
   660 
   661 * Uniform lattice theory development in HOL.
   662 
   663     constants "meet" and "join" now named "inf" and "sup"
   664     constant "Meet" now named "Inf"
   665 
   666     classes "meet_semilorder" and "join_semilorder" now named
   667       "lower_semilattice" and "upper_semilattice"
   668     class "lorder" now named "lattice"
   669     class "comp_lat" now named "complete_lattice"
   670 
   671     Instantiation of lattice classes allows explicit definitions
   672     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   673 
   674   INCOMPATIBILITY.  Theorem renames:
   675 
   676     meet_left_le            ~> inf_le1
   677     meet_right_le           ~> inf_le2
   678     join_left_le            ~> sup_ge1
   679     join_right_le           ~> sup_ge2
   680     meet_join_le            ~> inf_sup_ord
   681     le_meetI                ~> le_infI
   682     join_leI                ~> le_supI
   683     le_meet                 ~> le_inf_iff
   684     le_join                 ~> ge_sup_conv
   685     meet_idempotent         ~> inf_idem
   686     join_idempotent         ~> sup_idem
   687     meet_comm               ~> inf_commute
   688     join_comm               ~> sup_commute
   689     meet_leI1               ~> le_infI1
   690     meet_leI2               ~> le_infI2
   691     le_joinI1               ~> le_supI1
   692     le_joinI2               ~> le_supI2
   693     meet_assoc              ~> inf_assoc
   694     join_assoc              ~> sup_assoc
   695     meet_left_comm          ~> inf_left_commute
   696     meet_left_idempotent    ~> inf_left_idem
   697     join_left_comm          ~> sup_left_commute
   698     join_left_idempotent    ~> sup_left_idem
   699     meet_aci                ~> inf_aci
   700     join_aci                ~> sup_aci
   701     le_def_meet             ~> le_iff_inf
   702     le_def_join             ~> le_iff_sup
   703     join_absorp2            ~> sup_absorb2
   704     join_absorp1            ~> sup_absorb1
   705     meet_absorp1            ~> inf_absorb1
   706     meet_absorp2            ~> inf_absorb2
   707     meet_join_absorp        ~> inf_sup_absorb
   708     join_meet_absorp        ~> sup_inf_absorb
   709     distrib_join_le         ~> distrib_sup_le
   710     distrib_meet_le         ~> distrib_inf_le
   711 
   712     add_meet_distrib_left   ~> add_inf_distrib_left
   713     add_join_distrib_left   ~> add_sup_distrib_left
   714     is_join_neg_meet        ~> is_join_neg_inf
   715     is_meet_neg_join        ~> is_meet_neg_sup
   716     add_meet_distrib_right  ~> add_inf_distrib_right
   717     add_join_distrib_right  ~> add_sup_distrib_right
   718     add_meet_join_distribs  ~> add_sup_inf_distribs
   719     join_eq_neg_meet        ~> sup_eq_neg_inf
   720     meet_eq_neg_join        ~> inf_eq_neg_sup
   721     add_eq_meet_join        ~> add_eq_inf_sup
   722     meet_0_imp_0            ~> inf_0_imp_0
   723     join_0_imp_0            ~> sup_0_imp_0
   724     meet_0_eq_0             ~> inf_0_eq_0
   725     join_0_eq_0             ~> sup_0_eq_0
   726     neg_meet_eq_join        ~> neg_inf_eq_sup
   727     neg_join_eq_meet        ~> neg_sup_eq_inf
   728     join_eq_if              ~> sup_eq_if
   729 
   730     mono_meet               ~> mono_inf
   731     mono_join               ~> mono_sup
   732     meet_bool_eq            ~> inf_bool_eq
   733     join_bool_eq            ~> sup_bool_eq
   734     meet_fun_eq             ~> inf_fun_eq
   735     join_fun_eq             ~> sup_fun_eq
   736     meet_set_eq             ~> inf_set_eq
   737     join_set_eq             ~> sup_set_eq
   738     meet1_iff               ~> inf1_iff
   739     meet2_iff               ~> inf2_iff
   740     meet1I                  ~> inf1I
   741     meet2I                  ~> inf2I
   742     meet1D1                 ~> inf1D1
   743     meet2D1                 ~> inf2D1
   744     meet1D2                 ~> inf1D2
   745     meet2D2                 ~> inf2D2
   746     meet1E                  ~> inf1E
   747     meet2E                  ~> inf2E
   748     join1_iff               ~> sup1_iff
   749     join2_iff               ~> sup2_iff
   750     join1I1                 ~> sup1I1
   751     join2I1                 ~> sup2I1
   752     join1I1                 ~> sup1I1
   753     join2I2                 ~> sup1I2
   754     join1CI                 ~> sup1CI
   755     join2CI                 ~> sup2CI
   756     join1E                  ~> sup1E
   757     join2E                  ~> sup2E
   758 
   759     is_meet_Meet            ~> is_meet_Inf
   760     Meet_bool_def           ~> Inf_bool_def
   761     Meet_fun_def            ~> Inf_fun_def
   762     Meet_greatest           ~> Inf_greatest
   763     Meet_lower              ~> Inf_lower
   764     Meet_set_def            ~> Inf_set_def
   765 
   766     Sup_def                 ~> Sup_Inf
   767     Sup_bool_eq             ~> Sup_bool_def
   768     Sup_fun_eq              ~> Sup_fun_def
   769     Sup_set_eq              ~> Sup_set_def
   770 
   771     listsp_meetI            ~> listsp_infI
   772     listsp_meet_eq          ~> listsp_inf_eq
   773 
   774     meet_min                ~> inf_min
   775     join_max                ~> sup_max
   776 
   777 * Added syntactic class "size"; overloaded constant "size" now has
   778 type "'a::size ==> bool"
   779 
   780 * Internal reorganisation of `size' of datatypes: size theorems
   781 "foo.size" are no longer subsumed by "foo.simps" (but are still
   782 simplification rules by default!); theorems "prod.size" now named
   783 "*.size".
   784 
   785 * Class "div" now inherits from class "times" rather than "type".
   786 INCOMPATIBILITY.
   787 
   788 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   789 Linorder etc.  have disappeared; operations defined in terms of
   790 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   791 
   792 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
   793 
   794 * HOL-Word: New extensive library and type for generic, fixed size
   795 machine words, with arithemtic, bit-wise, shifting and rotating
   796 operations, reflection into int, nat, and bool lists, automation for
   797 linear arithmetic (by automatic reflection into nat or int), including
   798 lemmas on overflow and monotonicity.  Instantiated to all appropriate
   799 arithmetic type classes, supporting automatic simplification of
   800 numerals on all operations.
   801 
   802 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   803 
   804 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   805 
   806 * Code generator library theories:
   807   - Code_Integer represents HOL integers by big integer literals in target
   808     languages.
   809   - Code_Char represents HOL characters by character literals in target
   810     languages.
   811   - Code_Char_chr like Code_Char, but also offers treatment of character
   812     codes; includes Code_Integer.
   813   - Executable_Set allows to generate code for finite sets using lists.
   814   - Executable_Rat implements rational numbers as triples (sign, enumerator,
   815     denominator).
   816   - Executable_Real implements a subset of real numbers, namly those
   817     representable by rational numbers.
   818   - Efficient_Nat implements natural numbers by integers, which in general will
   819     result in higher efficency; pattern matching with 0/Suc is eliminated;
   820     includes Code_Integer.
   821   - Code_Index provides an additional datatype index which is mapped to
   822     target-language built-in integers.
   823   - Code_Message provides an additional datatype message_string} which is isomorphic to
   824     strings; messages are mapped to target-language strings.
   825 
   826 * New package for inductive predicates
   827 
   828   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   829 
   830     inductive
   831       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   832       for z_1 :: U_1 and ... and z_n :: U_m
   833     where
   834       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   835     | ...
   836 
   837   with full support for type-inference, rather than
   838 
   839     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   840 
   841     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   842     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   843 
   844     inductive "s z_1 ... z_m"
   845     intros
   846       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   847       ...
   848 
   849   For backward compatibility, there is a wrapper allowing inductive
   850   sets to be defined with the new package via
   851 
   852     inductive_set
   853       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   854       for z_1 :: U_1 and ... and z_n :: U_m
   855     where
   856       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   857     | ...
   858 
   859   or
   860 
   861     inductive_set
   862       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   863       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   864       for z_1 :: U_1 and ... and z_n :: U_m
   865     where
   866       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   867     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   868     | ...
   869 
   870   if the additional syntax "p ..." is required.
   871 
   872   Numerous examples can be found in the subdirectories src/HOL/Auth,
   873   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
   874 
   875   INCOMPATIBILITIES:
   876 
   877   - Since declaration and definition of inductive sets or predicates
   878     is no longer separated, abbreviations involving the newly
   879     introduced sets or predicates must be specified together with the
   880     introduction rules after the 'where' keyword (see above), rather
   881     than before the actual inductive definition.
   882 
   883   - The variables in induction and elimination rules are now
   884     quantified in the order of their occurrence in the introduction
   885     rules, rather than in alphabetical order. Since this may break
   886     some proofs, these proofs either have to be repaired, e.g. by
   887     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
   888     statements of the form
   889 
   890       case (rule_i a_i_1 ... a_i_{k_i})
   891 
   892     or the old order of quantification has to be restored by explicitly adding
   893     meta-level quantifiers in the introduction rules, i.e.
   894 
   895       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   896 
   897   - The format of the elimination rules is now
   898 
   899       p z_1 ... z_m x_1 ... x_n ==>
   900         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   901         ==> ... ==> P
   902 
   903     for predicates and
   904 
   905       (x_1, ..., x_n) : s z_1 ... z_m ==>
   906         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   907         ==> ... ==> P
   908 
   909     for sets rather than
   910 
   911       x : s z_1 ... z_m ==>
   912         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   913         ==> ... ==> P
   914 
   915     This may require terms in goals to be expanded to n-tuples
   916     (e.g. using case_tac or simplification with the split_paired_all
   917     rule) before the above elimination rule is applicable.
   918 
   919   - The elimination or case analysis rules for (mutually) inductive
   920     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
   921     list of rules "p_1_..._p_k.elims" is no longer available.
   922 
   923 * New package "function"/"fun" for general recursive functions,
   924 supporting mutual and nested recursion, definitions in local contexts,
   925 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
   926 for small examples, and the separate tutorial on the function
   927 package. The old recdef "package" is still available as before, but
   928 users are encouraged to use the new package.
   929 
   930 * Method "lexicographic_order" automatically synthesizes termination
   931 relations as lexicographic combinations of size measures. 
   932 
   933 * Case-expressions allow arbitrary constructor-patterns (including
   934 "_") and take their order into account, like in functional
   935 programming.  Internally, this is translated into nested
   936 case-expressions; missing cases are added and mapped to the predefined
   937 constant "undefined". In complicated cases printing may no longer show
   938 the original input but the internal form. Lambda-abstractions allow
   939 the same form of pattern matching: "% pat1 => e1 | ..." is an
   940 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
   941 variable.
   942 
   943 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   944 is an abbreviation for "of_nat :: nat => int". The simplification
   945 rules for "of_nat" have been changed to work like "int" did
   946 previously.  Potential INCOMPATIBILITY:
   947   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   948   - of_nat_diff and of_nat_mult are no longer default simp rules
   949 
   950 * Method "algebra" solves polynomial equations over (semi)rings using
   951 Groebner bases. The (semi)ring structure is defined by locales and the
   952 tool setup depends on that generic context. Installing the method for
   953 a specific type involves instantiating the locale and possibly adding
   954 declarations for computation on the coefficients.  The method is
   955 already instantiated for natural numbers and for the axiomatic class
   956 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
   957 CALCULEMUS 2007 for the general principles underlying this
   958 architecture of context-aware proof-tools.
   959 
   960 * Method "ferrack" implements quantifier elimination over
   961 special-purpose dense linear orders using locales (analogous to
   962 "algebra"). The method is already installed for class
   963 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
   964 rat, etc.
   965 
   966 * Former constant "List.op @" now named "List.append".  Use ML
   967 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
   968 circumvent possible incompatibilities when working on ML level.
   969 
   970 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
   971 
   972 * New function listsum :: 'a list => 'a for arbitrary monoids.
   973 Special syntax: "SUM x <- xs. f x" (and latex variants)
   974 
   975 * New syntax for Haskell-like list comprehension (input only), eg.
   976 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
   977 
   978 * The special syntax for function "filter" has changed from [x :
   979 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
   980 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
   981 
   982 * [a..b] is now defined for arbitrary linear orders.  It used to be
   983 defined on nat only, as an abbreviation for [a..<Suc b]
   984 INCOMPATIBILITY.
   985 
   986 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
   987 
   988 * New functions "sorted" and "sort" in src/HOL/List.thy.
   989 
   990 * New lemma collection field_simps (an extension of ring_simps) for
   991 manipulating (in)equations involving division. Multiplies with all
   992 denominators that can be proved to be non-zero (in equations) or
   993 positive/negative (in inequations).
   994 
   995 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   996 have been improved and renamed to ring_simps, group_simps and
   997 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
   998 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
   999 
  1000 * Theory Library/Commutative_Ring: switched from recdef to function
  1001 package; constants add, mul, pow now curried.  Infix syntax for
  1002 algebraic operations.
  1003 
  1004 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1005 INCOMPATIBILITY.
  1006 
  1007 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1008 INCOMPATIBILITY.
  1009 
  1010 * HOL/records: generalised field-update to take a function on the
  1011 field rather than the new value: r(|A := x|) is translated to A_update
  1012 (K x) r The K-combinator that is internally used is called K_record.
  1013 INCOMPATIBILITY: Usage of the plain update functions has to be
  1014 adapted.
  1015  
  1016 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1017 * x = 0, which are required for a semiring.  Richer structures do not
  1018 inherit from semiring_0 anymore, because this property is a theorem
  1019 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1020 there is more to prove, but this is mostly trivial.
  1021 
  1022 * Class "recpower" is generalized to arbitrary monoids, not just
  1023 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1024 commutativity or semiring properties additionally.
  1025 
  1026 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1027 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1028 better use 'abbreviation'.
  1029 
  1030 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1031 
  1032 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1033 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1034 significant changes for setting up numeral syntax for types:
  1035   - New constants Numeral.pred and Numeral.succ instead
  1036       of former Numeral.bin_pred and Numeral.bin_succ.
  1037   - Use integer operations instead of bin_add, bin_mult and so on.
  1038   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1039   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1040 
  1041 See src/HOL/Integ/IntArith.thy for an example setup.
  1042 
  1043 * Command 'normal_form' computes the normal form of a term that may
  1044 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1045 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1046 heavy-duty computations because the functions are compiled to ML
  1047 first.  Correspondingly, a method "normalization" is provided.  See
  1048 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1049 
  1050 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1051 25 like -->); output depends on the "iff" print_mode, the default is
  1052 "A = B" (with priority 50).
  1053 
  1054 * Relations less (<) and less_eq (<=) are also available on type bool.
  1055 Modified syntax to disallow nesting without explicit parentheses,
  1056 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1057 INCOMPATIBILITY.
  1058 
  1059 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1060 
  1061 * Relation composition operator "op O" now has precedence 75 and binds
  1062 stronger than union and intersection. INCOMPATIBILITY.
  1063 
  1064 * The old set interval syntax "{m..n(}" (and relatives) has been
  1065 removed.  Use "{m..<n}" (and relatives) instead.
  1066 
  1067 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1068 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1069 ``declare [[simproc del: neq]]''.
  1070 
  1071 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1072 True/False.
  1073 
  1074 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1075 
  1076 * Theorem setsum_mult renamed to setsum_right_distrib.
  1077 
  1078 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1079 ``rule'' method.
  1080 
  1081 * Reimplemented methods "sat" and "satx", with several improvements:
  1082 goals no longer need to be stated as "<prems> ==> False", equivalences
  1083 (i.e. "=" on type bool) are handled, variable names of the form
  1084 "lit_<n>" are no longer reserved, significant speedup.
  1085 
  1086 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1087 zChaff is still supported as well.
  1088 
  1089 * 'inductive' and 'datatype': provide projections of mutual rules,
  1090 bundled as foo_bar.inducts;
  1091 
  1092 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1093 Library.
  1094 
  1095 * Library: moved theory Accessible_Part to main HOL.
  1096 
  1097 * Library: added theory Coinductive_List of potentially infinite lists
  1098 as greatest fixed-point.
  1099 
  1100 * Library: added theory AssocList which implements (finite) maps as
  1101 association lists.
  1102 
  1103 * Method "evaluation" solves goals (i.e. a boolean expression)
  1104 efficiently by compiling it to ML.  The goal is "proved" (via an
  1105 oracle) if it evaluates to True.
  1106 
  1107 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1108 also when invoked by the simplifier.  This results in the Simplifier
  1109 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1110 Configuration option fast_arith_split_limit=0 recovers the old
  1111 behavior.
  1112 
  1113 * Support for hex (0x20) and binary (0b1001) numerals.
  1114 
  1115 * New method: reify eqs (t), where eqs are equations for an
  1116 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1117 parameter, computes a term s::'b and a list xs::'a list and proves the
  1118 theorem I xs s = t. This is also known as reification or quoting. The
  1119 resulting theorem is applied to the subgoal to substitute t with I xs
  1120 s.  If t is omitted, the subgoal itself is reified.
  1121 
  1122 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1123 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1124 where f is supposed to be a computable function (in the sense of code
  1125 generattion). The method uses reify to compute s and xs as above then
  1126 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1127 r and finally gets the theorem t = r, which is again applied to the
  1128 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1129 
  1130 * Reflection: Automatic reification now handels binding, an example is
  1131 available in src/HOL/ex/ReflectionEx.thy
  1132 
  1133 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1134 command 'statespace' that is similar to 'record', but introduces an
  1135 abstract specification based on the locale infrastructure instead of
  1136 HOL types.  This leads to extra flexibility in composing state spaces,
  1137 in particular multiple inheritance and renaming of components.
  1138 
  1139 
  1140 *** HOL-Complex ***
  1141 
  1142 * Hyperreal: Functions root and sqrt are now defined on negative real
  1143 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1144 Nonnegativity side conditions have been removed from many lemmas, so
  1145 that more subgoals may now be solved by simplification; potential
  1146 INCOMPATIBILITY.
  1147 
  1148 * Real: new type classes formalize real normed vector spaces and
  1149 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1150 and norm :: 'a => real.
  1151 
  1152 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1153 reals into other types. The overloaded constant Reals :: 'a set is now
  1154 defined as range of_real; potential INCOMPATIBILITY.
  1155 
  1156 * Real: proper support for ML code generation, including 'quickcheck'.
  1157 Reals are implemented as arbitrary precision rationals.
  1158 
  1159 * Hyperreal: Several constants that previously worked only for the
  1160 reals have been generalized, so they now work over arbitrary vector
  1161 spaces. Type annotations may need to be added in some cases; potential
  1162 INCOMPATIBILITY.
  1163 
  1164   Infinitesimal  :: ('a::real_normed_vector) star set
  1165   HFinite        :: ('a::real_normed_vector) star set
  1166   HInfinite      :: ('a::real_normed_vector) star set
  1167   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1168   monad          :: ('a::real_normed_vector) star => 'a star set
  1169   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1170   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1171   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1172   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1173   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1174   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1175   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1176   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1177   sgn            :: 'a::real_normed_vector => 'a
  1178   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1179 
  1180 * Complex: Some complex-specific constants are now abbreviations for
  1181 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1182 hnorm.  Other constants have been entirely removed in favor of the
  1183 polymorphic versions (INCOMPATIBILITY):
  1184 
  1185   approx        <-- capprox
  1186   HFinite       <-- CFinite
  1187   HInfinite     <-- CInfinite
  1188   Infinitesimal <-- CInfinitesimal
  1189   monad         <-- cmonad
  1190   galaxy        <-- cgalaxy
  1191   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1192   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1193   (ns)deriv     <-- (ns)cderiv
  1194 
  1195 
  1196 *** HOL-Algebra ***
  1197 
  1198 * Formalisation of ideals and the quotient construction over rings.
  1199 
  1200 * Order and lattice theory no longer based on records.
  1201 INCOMPATIBILITY.
  1202 
  1203 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1204 greatest_closed.  INCOMPATIBILITY.
  1205 
  1206 * Method algebra is now set up via an attribute.  For examples see
  1207 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1208 of algebraic structures.
  1209 
  1210 * Renamed theory CRing to Ring.
  1211 
  1212 
  1213 *** HOL-Nominal ***
  1214 
  1215 * Substantial, yet incomplete support for nominal datatypes (binding
  1216 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1217 src/HOL/Nominal/Examples.  Prospective users should consult
  1218 http://isabelle.in.tum.de/nominal/
  1219 
  1220 
  1221 *** ML ***
  1222 
  1223 * ML basics: just one true type int, which coincides with IntInf.int
  1224 (even on SML/NJ).
  1225 
  1226 * ML within Isar: antiquotations allow to embed statically-checked
  1227 formal entities in the source, referring to the context available at
  1228 compile-time.  For example:
  1229 
  1230 ML {* @{sort "{zero,one}"} *}
  1231 ML {* @{typ "'a => 'b"} *}
  1232 ML {* @{term "%x. x"} *}
  1233 ML {* @{prop "x == y"} *}
  1234 ML {* @{ctyp "'a => 'b"} *}
  1235 ML {* @{cterm "%x. x"} *}
  1236 ML {* @{cprop "x == y"} *}
  1237 ML {* @{thm asm_rl} *}
  1238 ML {* @{thms asm_rl} *}
  1239 ML {* @{type_name c} *}
  1240 ML {* @{type_syntax c} *}
  1241 ML {* @{const_name c} *}
  1242 ML {* @{const_syntax c} *}
  1243 ML {* @{context} *}
  1244 ML {* @{theory} *}
  1245 ML {* @{theory Pure} *}
  1246 ML {* @{theory_ref} *}
  1247 ML {* @{theory_ref Pure} *}
  1248 ML {* @{simpset} *}
  1249 ML {* @{claset} *}
  1250 ML {* @{clasimpset} *}
  1251 
  1252 The same works for sources being ``used'' within an Isar context.
  1253 
  1254 * ML in Isar: improved error reporting; extra verbosity with
  1255 ML_Context.trace enabled.
  1256 
  1257 * Pure/General/table.ML: the join operations now works via exceptions
  1258 DUP/SAME instead of type option. This is simpler in simple cases, and
  1259 admits slightly more efficient complex applications.
  1260 
  1261 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1262 use Context.generic instead of just theory.
  1263 
  1264 * Pure: datatype Context.generic joins theory/Proof.context and
  1265 provides some facilities for code that works in either kind of
  1266 context, notably GenericDataFun for uniform theory and proof data.
  1267 
  1268 * Pure: simplified internal attribute type, which is now always
  1269 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1270 local (Proof.context) attributes have been discontinued, while
  1271 minimizing code duplication. Thm.rule_attribute and
  1272 Thm.declaration_attribute build canonical attributes; see also structure
  1273 Context for further operations on Context.generic, notably
  1274 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1275 declarations and definitions.
  1276 
  1277 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1278 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1279 init only required for impure data. INCOMPATIBILITY: empty really need
  1280 to be empty (no dependencies on theory content!)
  1281 
  1282 * Pure/kernel: consts certification ignores sort constraints given in
  1283 signature declarations. (This information is not relevant to the
  1284 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1285 potential INCOMPATIBILITY.
  1286 
  1287 * Pure: axiomatic type classes are now purely definitional, with
  1288 explicit proofs of class axioms and super class relations performed
  1289 internally. See Pure/axclass.ML for the main internal interfaces --
  1290 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1291 AxClass.axiomatize_class/classrel/arity supersede
  1292 Sign.add_classes/classrel/arities.
  1293 
  1294 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1295 global/local versions on theory vs. Proof.context have been
  1296 discontinued; Attrib.syntax and Method.syntax have been adapted
  1297 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1298 attributes, methods, etc.
  1299 
  1300 * Pure: several functions of signature "... -> theory -> theory * ..."
  1301 have been reoriented to "... -> theory -> ... * theory" in order to
  1302 allow natural usage in combination with the ||>, ||>>, |-> and
  1303 fold_map combinators.
  1304 
  1305 * Pure: official theorem names (closed derivations) and additional
  1306 comments (tags) are now strictly separate.  Name hints -- which are
  1307 maintained as tags -- may be attached any time without affecting the
  1308 derivation.
  1309 
  1310 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1311 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1312 achieve the old behaviour.
  1313 
  1314 * Pure: the "Goal" constant is now called "prop", supporting a
  1315 slightly more general idea of ``protecting'' meta-level rule
  1316 statements.
  1317 
  1318 * Pure: Logic.(un)varify only works in a global context, which is now
  1319 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1320 Logic.legacy_(un)varify as temporary workaround.
  1321 
  1322 * Pure: structure Name provides scalable operations for generating
  1323 internal variable names, notably Name.variants etc.  This replaces
  1324 some popular functions from term.ML:
  1325 
  1326   Term.variant		->  Name.variant
  1327   Term.variantlist	->  Name.variant_list
  1328   Term.invent_names	->  Name.invent_list
  1329 
  1330 Note that low-level renaming rarely occurs in new code -- operations
  1331 from structure Variable are used instead (see below).
  1332 
  1333 * Pure: structure Variable provides fundamental operations for proper
  1334 treatment of fixed/schematic variables in a context.  For example,
  1335 Variable.import introduces fixes for schematics of given facts and
  1336 Variable.export reverses the effect (up to renaming) -- this replaces
  1337 various freeze_thaw operations.
  1338 
  1339 * Pure: structure Goal provides simple interfaces for
  1340 init/conclude/finish and tactical prove operations (replacing former
  1341 Tactic.prove).  Goal.prove is the canonical way to prove results
  1342 within a given context; Goal.prove_global is a degraded version for
  1343 theory level goals, including a global Drule.standard.  Note that
  1344 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1345 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1346 in a locale context).
  1347 
  1348 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1349 and type checking (Syntax.check_term etc.), with common combinations
  1350 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1351 which are considered legacy and await removal.
  1352 
  1353 * Pure/Syntax: generic interfaces for type unchecking
  1354 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1355 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1356 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1357 available for convenience, but refer to the very same operations using
  1358 a mere theory instead of a full context.
  1359 
  1360 * Isar: simplified treatment of user-level errors, using exception
  1361 ERROR of string uniformly.  Function error now merely raises ERROR,
  1362 without any side effect on output channels.  The Isar toplevel takes
  1363 care of proper display of ERROR exceptions.  ML code may use plain
  1364 handle/can/try; cat_error may be used to concatenate errors like this:
  1365 
  1366   ... handle ERROR msg => cat_error msg "..."
  1367 
  1368 Toplevel ML code (run directly or through the Isar toplevel) may be
  1369 embedded into the Isar toplevel with exception display/debug like
  1370 this:
  1371 
  1372   Isar.toplevel (fn () => ...)
  1373 
  1374 INCOMPATIBILITY, removed special transform_error facilities, removed
  1375 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1376 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1377 -- use plain ERROR instead.
  1378 
  1379 * Isar: theory setup now has type (theory -> theory), instead of a
  1380 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1381 
  1382 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1383 ProofContext.debug/verbose flags.
  1384 
  1385 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1386 theory before entering a proof state.  Transactions now always see a
  1387 quasi-functional intermediate checkpoint, both in interactive and
  1388 batch mode.
  1389 
  1390 * Isar: simplified interfaces for outer syntax.  Renamed
  1391 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1392 OuterSyntax.add_parsers -- this functionality is now included in
  1393 OuterSyntax.command etc.  INCOMPATIBILITY.
  1394 
  1395 * Simplifier: the simpset of a running simplification process now
  1396 contains a proof context (cf. Simplifier.the_context), which is the
  1397 very context that the initial simpset has been retrieved from (by
  1398 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1399 (solver, looper etc.) may depend on arbitrary proof data.
  1400 
  1401 * Simplifier.inherit_context inherits the proof context (plus the
  1402 local bounds) of the current simplification process; any simproc
  1403 etc. that calls the Simplifier recursively should do this!  Removed
  1404 former Simplifier.inherit_bounds, which is already included here --
  1405 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1406 specify an explicit context using Simplifier.context/theory_context.
  1407 
  1408 * Simplifier/Classical Reasoner: more abstract interfaces
  1409 change_simpset/claset for modifying the simpset/claset reference of a
  1410 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1411 INCOMPATIBILITY.
  1412 
  1413 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1414 "Trueprop" etc.
  1415 
  1416 
  1417 *** System ***
  1418 
  1419 * settings: the default heap location within ISABELLE_HOME_USER now
  1420 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1421 Isabelle installations.
  1422 
  1423 * isabelle-process: option -S (secure mode) disables some critical
  1424 operations, notably runtime compilation and evaluation of ML source
  1425 code.
  1426 
  1427 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1428 
  1429 * Support for parallel execution, using native multicore support of
  1430 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1431 independent theories, according to the given theory header
  1432 specifications. The maximum number of worker threads is specified via
  1433 usedir option -M or the "max-threads" setting in Proof General. A
  1434 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1435 to 6 on a 8-core machine.  User-code needs to observe certain
  1436 guidelines for thread-safe programming, see appendix A in the Isar
  1437 Implementation manual.
  1438 
  1439 
  1440 
  1441 New in Isabelle2005 (October 2005)
  1442 ----------------------------------
  1443 
  1444 *** General ***
  1445 
  1446 * Theory headers: the new header syntax for Isar theories is
  1447 
  1448   theory <name>
  1449   imports <theory1> ... <theoryN>
  1450   uses <file1> ... <fileM>
  1451   begin
  1452 
  1453 where the 'uses' part is optional.  The previous syntax
  1454 
  1455   theory <name> = <theory1> + ... + <theoryN>:
  1456 
  1457 will disappear in the next release.  Use isatool fixheaders to convert
  1458 existing theory files.  Note that there is no change in ancient
  1459 non-Isar theories now, but these will disappear soon.
  1460 
  1461 * Theory loader: parent theories can now also be referred to via
  1462 relative and absolute paths.
  1463 
  1464 * Command 'find_theorems' searches for a list of criteria instead of a
  1465 list of constants. Known criteria are: intro, elim, dest, name:string,
  1466 simp:term, and any term. Criteria can be preceded by '-' to select
  1467 theorems that do not match. Intro, elim, dest select theorems that
  1468 match the current goal, name:s selects theorems whose fully qualified
  1469 name contain s, and simp:term selects all simplification rules whose
  1470 lhs match term.  Any other term is interpreted as pattern and selects
  1471 all theorems matching the pattern. Available in ProofGeneral under
  1472 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1473 
  1474   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1475 
  1476 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1477 matching the current goal as introduction rule and not having "HOL."
  1478 in their name (i.e. not being defined in theory HOL).
  1479 
  1480 * Command 'thms_containing' has been discontinued in favour of
  1481 'find_theorems'; INCOMPATIBILITY.
  1482 
  1483 * Communication with Proof General is now 8bit clean, which means that
  1484 Unicode text in UTF-8 encoding may be used within theory texts (both
  1485 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1486 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1487 
  1488   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1489   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1490 
  1491 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1492 Classical Reasoner.  Typical big applications run around 2 times
  1493 faster.
  1494 
  1495 
  1496 *** Document preparation ***
  1497 
  1498 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1499 of raw sources.  Only those symbols that do not require additional
  1500 LaTeX packages (depending on comments in isabellesym.sty) are
  1501 displayed properly, everything else is left verbatim.  isatool display
  1502 and isatool print are used as front ends (these are subject to the
  1503 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1504 
  1505 * Command tags control specific markup of certain regions of text,
  1506 notably folding and hiding.  Predefined tags include "theory" (for
  1507 theory begin and end), "proof" for proof commands, and "ML" for
  1508 commands involving ML code; the additional tags "visible" and
  1509 "invisible" are unused by default.  Users may give explicit tag
  1510 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1511 interpretation of tags is determined by the LaTeX job during document
  1512 preparation: see option -V of isatool usedir, or options -n and -t of
  1513 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1514 \isadroptag.
  1515 
  1516 Several document versions may be produced at the same time via isatool
  1517 usedir (the generated index.html will link all of them).  Typical
  1518 specifications include ''-V document=theory,proof,ML'' to present
  1519 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1520 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1521 these parts without any formal replacement text.  The Isabelle site
  1522 default settings produce ''document'' and ''outline'' versions as
  1523 specified above.
  1524 
  1525 * Several new antiquotations:
  1526 
  1527   @{term_type term} prints a term with its type annotated;
  1528 
  1529   @{typeof term} prints the type of a term;
  1530 
  1531   @{const const} is the same as @{term const}, but checks that the
  1532   argument is a known logical constant;
  1533 
  1534   @{term_style style term} and @{thm_style style thm} print a term or
  1535   theorem applying a "style" to it
  1536 
  1537   @{ML text}
  1538 
  1539 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1540 definitions, equations, inequations etc., 'concl' printing only the
  1541 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1542 to print the specified premise.  TermStyle.add_style provides an ML
  1543 interface for introducing further styles.  See also the "LaTeX Sugar"
  1544 document practical applications.  The ML antiquotation prints
  1545 type-checked ML expressions verbatim.
  1546 
  1547 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1548 and 'text' support optional locale specification '(in loc)', which
  1549 specifies the default context for interpreting antiquotations.  For
  1550 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1551 
  1552 * Option 'locale=NAME' of antiquotations specifies an alternative
  1553 context interpreting the subsequent argument.  For example: @{thm
  1554 [locale=lattice] inf_assoc}.
  1555 
  1556 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1557 a proof context.
  1558 
  1559 * Proper output of antiquotations for theory commands involving a
  1560 proof context (such as 'locale' or 'theorem (in loc) ...').
  1561 
  1562 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1563 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1564 
  1565 * isatool usedir: new option -C (default true) controls whether option
  1566 -D should include a copy of the original document directory; -C false
  1567 prevents unwanted effects such as copying of administrative CVS data.
  1568 
  1569 
  1570 *** Pure ***
  1571 
  1572 * Considerably improved version of 'constdefs' command.  Now performs
  1573 automatic type-inference of declared constants; additional support for
  1574 local structure declarations (cf. locales and HOL records), see also
  1575 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1576 sequential dependencies of definitions within a single 'constdefs'
  1577 section; moreover, the declared name needs to be an identifier.  If
  1578 all fails, consider to fall back on 'consts' and 'defs' separately.
  1579 
  1580 * Improved indexed syntax and implicit structures.  First of all,
  1581 indexed syntax provides a notational device for subscripted
  1582 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1583 expressions.  Secondly, in a local context with structure
  1584 declarations, number indexes \<^sub>n or the empty index (default
  1585 number 1) refer to a certain fixed variable implicitly; option
  1586 show_structs controls printing of implicit structures.  Typical
  1587 applications of these concepts involve record types and locales.
  1588 
  1589 * New command 'no_syntax' removes grammar declarations (and
  1590 translations) resulting from the given syntax specification, which is
  1591 interpreted in the same manner as for the 'syntax' command.
  1592 
  1593 * 'Advanced' translation functions (parse_translation etc.) may depend
  1594 on the signature of the theory context being presently used for
  1595 parsing/printing, see also isar-ref manual.
  1596 
  1597 * Improved 'oracle' command provides a type-safe interface to turn an
  1598 ML expression of type theory -> T -> term into a primitive rule of
  1599 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1600 is already included here); see also FOL/ex/IffExample.thy;
  1601 INCOMPATIBILITY.
  1602 
  1603 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1604 before); "cI" is no longer bound, use "c.intro" instead.
  1605 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1606 axclasses vs. locales.
  1607 
  1608 * Improved internal renaming of symbolic identifiers -- attach primes
  1609 instead of base 26 numbers.
  1610 
  1611 * New flag show_question_marks controls printing of leading question
  1612 marks in schematic variable names.
  1613 
  1614 * In schematic variable names, *any* symbol following \<^isub> or
  1615 \<^isup> is now treated as part of the base name.  For example, the
  1616 following works without printing of awkward ".0" indexes:
  1617 
  1618   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1619     by simp
  1620 
  1621 * Inner syntax includes (*(*nested*) comments*).
  1622 
  1623 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1624 annotations as "(00...)".
  1625 
  1626 * Clear separation of logical types and nonterminals, where the latter
  1627 may only occur in 'syntax' specifications or type abbreviations.
  1628 Before that distinction was only partially implemented via type class
  1629 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1630 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1631 exotic syntax specifications may require further adaption
  1632 (e.g. Cube/Cube.thy).
  1633 
  1634 * Removed obsolete type class "logic", use the top sort {} instead.
  1635 Note that non-logical types should be declared as 'nonterminals'
  1636 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1637 specifications.
  1638 
  1639 * Attributes 'induct' and 'cases': type or set names may now be
  1640 locally fixed variables as well.
  1641 
  1642 * Simplifier: can now control the depth to which conditional rewriting
  1643 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1644 Limit.
  1645 
  1646 * Simplifier: simplification procedures may now take the current
  1647 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1648 interface), which is very useful for calling the Simplifier
  1649 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1650 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1651 low-level mk_simproc no longer applies Logic.varify internally, to
  1652 allow for use in a context of fixed variables.
  1653 
  1654 * thin_tac now works even if the assumption being deleted contains !!
  1655 or ==>.  More generally, erule now works even if the major premise of
  1656 the elimination rule contains !! or ==>.
  1657 
  1658 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1659 
  1660 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1661 from Pure, which contains all common declarations already.  Both
  1662 theories are defined via plain Isabelle/Isar .thy files.
  1663 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1664 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1665 use isatool fixcpure to adapt your theory and ML sources.
  1666 
  1667 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1668 selections of theorems in named facts via index ranges.
  1669 
  1670 * 'print_theorems': in theory mode, really print the difference
  1671 wrt. the last state (works for interactive theory development only),
  1672 in proof mode print all local facts (cf. 'print_facts');
  1673 
  1674 * 'hide': option '(open)' hides only base names.
  1675 
  1676 * More efficient treatment of intermediate checkpoints in interactive
  1677 theory development.
  1678 
  1679 * Code generator is now invoked via code_module (incremental code
  1680 generation) and code_library (modular code generation, ML structures
  1681 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1682 must be quoted when used as identifiers.
  1683 
  1684 * New 'value' command for reading, evaluating and printing terms using
  1685 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1686 quoted when used as identifier.
  1687 
  1688 
  1689 *** Locales ***
  1690 
  1691 * New commands for the interpretation of locale expressions in
  1692 theories (1), locales (2) and proof contexts (3).  These generate
  1693 proof obligations from the expression specification.  After the
  1694 obligations have been discharged, theorems of the expression are added
  1695 to the theory, target locale or proof context.  The synopsis of the
  1696 commands is a follows:
  1697 
  1698   (1) interpretation expr inst
  1699   (2) interpretation target < expr
  1700   (3) interpret expr inst
  1701 
  1702 Interpretation in theories and proof contexts require a parameter
  1703 instantiation of terms from the current context.  This is applied to
  1704 specifications and theorems of the interpreted expression.
  1705 Interpretation in locales only permits parameter renaming through the
  1706 locale expression.  Interpretation is smart in that interpretations
  1707 that are active already do not occur in proof obligations, neither are
  1708 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1709 inspect active interpretations of a particular locale.  For details,
  1710 see the Isar Reference manual.  Examples can be found in
  1711 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1712 
  1713 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1714 'interpret' instead.
  1715 
  1716 * New context element 'constrains' for adding type constraints to
  1717 parameters.
  1718 
  1719 * Context expressions: renaming of parameters with syntax
  1720 redeclaration.
  1721 
  1722 * Locale declaration: 'includes' disallowed.
  1723 
  1724 * Proper static binding of attribute syntax -- i.e. types / terms /
  1725 facts mentioned as arguments are always those of the locale definition
  1726 context, independently of the context of later invocations.  Moreover,
  1727 locale operations (renaming and type / term instantiation) are applied
  1728 to attribute arguments as expected.
  1729 
  1730 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1731 actual attributes; rare situations may require Attrib.attribute to
  1732 embed those attributes into Attrib.src that lack concrete syntax.
  1733 Attribute implementations need to cooperate properly with the static
  1734 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1735 Attrib.XXX_thm etc. already do the right thing without further
  1736 intervention.  Only unusual applications -- such as "where" or "of"
  1737 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1738 on the context and the facts involved -- may have to assign parsed
  1739 values to argument tokens explicitly.
  1740 
  1741 * Changed parameter management in theorem generation for long goal
  1742 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1743 theorem statement in rare situations.
  1744 
  1745 * Locale inspection command 'print_locale' omits notes elements.  Use
  1746 'print_locale!' to have them included in the output.
  1747 
  1748 
  1749 *** Provers ***
  1750 
  1751 * Provers/hypsubst.ML: improved version of the subst method, for
  1752 single-step rewriting: it now works in bound variable contexts. New is
  1753 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1754 rewrite a different subterm than the original subst method, which is
  1755 still available as 'simplesubst'.
  1756 
  1757 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1758 and quasi orders.
  1759 
  1760 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1761 reflexive-transitive closure of relations.
  1762 
  1763 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1764 limit (previously hard-coded with a value of 20) user-definable.
  1765 
  1766 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1767 is peformed already.  Object-logics merely need to finish their
  1768 initial simpset configuration as before.  INCOMPATIBILITY.
  1769 
  1770 
  1771 *** HOL ***
  1772 
  1773 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1774 
  1775   syntax (epsilon)
  1776     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1777 
  1778 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1779 and x-symbol; use option '-m epsilon' to get it actually printed.
  1780 Moreover, the mathematically important symbolic identifier \<epsilon>
  1781 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1782 
  1783 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1784 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1785 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1786 support corresponding Isar calculations.
  1787 
  1788 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1789 instead of ":".
  1790 
  1791 * theory SetInterval: changed the syntax for open intervals:
  1792 
  1793   Old       New
  1794   {..n(}    {..<n}
  1795   {)n..}    {n<..}
  1796   {m..n(}   {m..<n}
  1797   {)m..n}   {m<..n}
  1798   {)m..n(}  {m<..<n}
  1799 
  1800 The old syntax is still supported but will disappear in the next
  1801 release.  For conversion use the following Emacs search and replace
  1802 patterns (these are not perfect but work quite well):
  1803 
  1804   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1805   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1806 
  1807 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1808 equalities in commutative rings; method 'algebra' provides a generic
  1809 interface.
  1810 
  1811 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1812 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1813 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1814 be a tuple pattern.
  1815 
  1816 Some new syntax forms are available:
  1817 
  1818   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1819   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1820   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1821   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1822 
  1823 The latter form "\<Sum>x < k. e" used to be based on a separate
  1824 function "Summation", which has been discontinued.
  1825 
  1826 * theory Finite_Set: in structured induction proofs, the insert case
  1827 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1828 (insert F x)'.
  1829 
  1830 * The 'refute' command has been extended to support a much larger
  1831 fragment of HOL, including axiomatic type classes, constdefs and
  1832 typedefs, inductive datatypes and recursion.
  1833 
  1834 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1835 Requires zChaff with proof generation to be installed.  See
  1836 HOL/ex/SAT_Examples.thy for examples.
  1837 
  1838 * Datatype induction via method 'induct' now preserves the name of the
  1839 induction variable. For example, when proving P(xs::'a list) by
  1840 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1841 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1842 in unstructured proof scripts.
  1843 
  1844 * Reworked implementation of records.  Improved scalability for
  1845 records with many fields, avoiding performance problems for type
  1846 inference. Records are no longer composed of nested field types, but
  1847 of nested extension types. Therefore the record type only grows linear
  1848 in the number of extensions and not in the number of fields.  The
  1849 top-level (users) view on records is preserved.  Potential
  1850 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1851 old record representation. The type generated for a record is called
  1852 <record_name>_ext_type.
  1853 
  1854 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1855 proofs triggered by a record definition or a simproc (if
  1856 quick_and_dirty is enabled).  Definitions of large records can take
  1857 quite long.
  1858 
  1859 New simproc record_upd_simproc for simplification of multiple record
  1860 updates enabled by default.  Moreover, trivial updates are also
  1861 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1862 occasionally, since simplification is more powerful by default.
  1863 
  1864 * typedef: proper support for polymorphic sets, which contain extra
  1865 type-variables in the term.
  1866 
  1867 * Simplifier: automatically reasons about transitivity chains
  1868 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1869 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1870 old proofs break occasionally as simplification may now solve more
  1871 goals than previously.
  1872 
  1873 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1874 present.  Works for all partial orders (class "order"), in particular
  1875 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1876 just like y <= x.
  1877 
  1878 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1879 bound variable or a constant then the let is unfolded.  Otherwise
  1880 first a is simplified to b, and then f b is simplified to g. If
  1881 possible we abstract b from g arriving at "let x = b in h x",
  1882 otherwise we unfold the let and arrive at g.  The simproc can be
  1883 enabled/disabled by the reference use_let_simproc.  Potential
  1884 INCOMPATIBILITY since simplification is more powerful by default.
  1885 
  1886 * Classical reasoning: the meson method now accepts theorems as arguments.
  1887 
  1888 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1889 jobs to provide advice on the provability of subgoals.
  1890 
  1891 * Theory OrderedGroup and Ring_and_Field: various additions and
  1892 improvements to faciliate calculations involving equalities and
  1893 inequalities.
  1894 
  1895 The following theorems have been eliminated or modified
  1896 (INCOMPATIBILITY):
  1897 
  1898   abs_eq             now named abs_of_nonneg
  1899   abs_of_ge_0        now named abs_of_nonneg
  1900   abs_minus_eq       now named abs_of_nonpos
  1901   imp_abs_id         now named abs_of_nonneg
  1902   imp_abs_neg_id     now named abs_of_nonpos
  1903   mult_pos           now named mult_pos_pos
  1904   mult_pos_le        now named mult_nonneg_nonneg
  1905   mult_pos_neg_le    now named mult_nonneg_nonpos
  1906   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1907   mult_neg           now named mult_neg_neg
  1908   mult_neg_le        now named mult_nonpos_nonpos
  1909 
  1910 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1911      
  1912      zero_le_square
  1913      not_square_less_zero 
  1914 
  1915   The following lemmas have been deleted from Real/RealPow:
  1916   
  1917      realpow_zero_zero
  1918      realpow_two
  1919      realpow_less
  1920      zero_le_power
  1921      realpow_two_le
  1922      abs_realpow_two
  1923      realpow_two_abs     
  1924 
  1925 * Theory Parity: added rules for simplifying exponents.
  1926 
  1927 * Theory List:
  1928 
  1929 The following theorems have been eliminated or modified
  1930 (INCOMPATIBILITY):
  1931 
  1932   list_all_Nil       now named list_all.simps(1)
  1933   list_all_Cons      now named list_all.simps(2)
  1934   list_all_conv      now named list_all_iff
  1935   set_mem_eq         now named mem_iff
  1936 
  1937 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1938 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1939 
  1940 
  1941 *** HOL-Complex ***
  1942 
  1943 * Theory RealDef: better support for embedding natural numbers and
  1944 integers in the reals.
  1945 
  1946 The following theorems have been eliminated or modified
  1947 (INCOMPATIBILITY):
  1948 
  1949   exp_ge_add_one_self  now requires no hypotheses
  1950   real_of_int_add      reversed direction of equality (use [symmetric])
  1951   real_of_int_minus    reversed direction of equality (use [symmetric])
  1952   real_of_int_diff     reversed direction of equality (use [symmetric])
  1953   real_of_int_mult     reversed direction of equality (use [symmetric])
  1954 
  1955 * Theory RComplete: expanded support for floor and ceiling functions.
  1956 
  1957 * Theory Ln is new, with properties of the natural logarithm
  1958 
  1959 * Hyperreal: There is a new type constructor "star" for making
  1960 nonstandard types.  The old type names are now type synonyms:
  1961 
  1962   hypreal = real star
  1963   hypnat = nat star
  1964   hcomplex = complex star
  1965 
  1966 * Hyperreal: Many groups of similarly-defined constants have been
  1967 replaced by polymorphic versions (INCOMPATIBILITY):
  1968 
  1969   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1970 
  1971   starset      <-- starsetNat, starsetC
  1972   *s*          <-- *sNat*, *sc*
  1973   starset_n    <-- starsetNat_n, starsetC_n
  1974   *sn*         <-- *sNatn*, *scn*
  1975   InternalSets <-- InternalNatSets, InternalCSets
  1976 
  1977   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1978   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1979   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1980   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1981   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1982 
  1983 * Hyperreal: Many type-specific theorems have been removed in favor of
  1984 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1985 
  1986   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1987   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1988   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1989   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1990   right_minus <-- hypreal_add_minus
  1991   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1992   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1993   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1994   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1995   mult_1_right <-- hcomplex_mult_one_right
  1996   mult_zero_left <-- hcomplex_mult_zero_left
  1997   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1998   right_distrib <-- hypnat_add_mult_distrib2
  1999   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2000   right_inverse <-- hypreal_mult_inverse
  2001   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2002   order_refl <-- {hypreal,hypnat}_le_refl
  2003   order_trans <-- {hypreal,hypnat}_le_trans
  2004   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2005   order_less_le <-- {hypreal,hypnat}_less_le
  2006   linorder_linear <-- {hypreal,hypnat}_le_linear
  2007   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2008   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2009   add_nonneg_nonneg <-- hypreal_le_add_order
  2010 
  2011 * Hyperreal: Separate theorems having to do with type-specific
  2012 versions of constants have been merged into theorems that apply to the
  2013 new polymorphic constants (INCOMPATIBILITY):
  2014 
  2015   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2016   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2017   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2018   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2019   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2020   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2021   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2022   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2023   STAR_diff <-- {STAR,STARC}_diff
  2024   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2025     STARC_hcomplex_of_complex}_image_subset
  2026   starset_n_Un <-- starset{Nat,C}_n_Un
  2027   starset_n_Int <-- starset{Nat,C}_n_Int
  2028   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2029   starset_n_diff <-- starset{Nat,C}_n_diff
  2030   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2031   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2032   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2033   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2034   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2035   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2036   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2037   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2038   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2039   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2040   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2041   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2042   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2043   starfun_diff <-- starfun{C,RC,CR}_diff
  2044   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2045   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2046   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2047   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2048   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2049   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2050   starfun_Id <-- starfunC_Id
  2051   starfun_approx <-- starfun{Nat,CR}_approx
  2052   starfun_capprox <-- starfun{C,RC}_capprox
  2053   starfun_abs <-- starfunNat_rabs
  2054   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2055   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2056   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2057   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2058   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2059   starfun_add_approx <-- starfunCR_add_approx
  2060   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2061   starfun_divide <-- starfun{C,CR,RC}_divide
  2062   starfun_n <-- starfun{Nat,C}_n
  2063   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2064   starfun_n_add <-- starfun{Nat,C}_n_add
  2065   starfun_n_add_minus <-- starfunNat_n_add_minus
  2066   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2067   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2068   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2069 
  2070   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2071   star_n_minus <-- {hypreal,hcomplex}_minus
  2072   star_n_diff <-- {hypreal,hcomplex}_diff
  2073   star_n_mult <-- {hypreal,hcomplex}_mult
  2074   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2075   star_n_le <-- {hypreal,hypnat}_le
  2076   star_n_less <-- {hypreal,hypnat}_less
  2077   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2078   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2079   star_n_abs <-- hypreal_hrabs
  2080   star_n_divide <-- hcomplex_divide
  2081 
  2082   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2083   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2084   star_of_diff <-- hypreal_of_real_diff
  2085   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2086   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2087   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2088   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2089   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2090   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2091   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2092   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2093   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2094   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2095   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2096   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2097   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2098   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2099   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2100   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2101   star_of_power <-- hypreal_of_real_power
  2102   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2103 
  2104 * Hyperreal: new method "transfer" that implements the transfer
  2105 principle of nonstandard analysis. With a subgoal that mentions
  2106 nonstandard types like "'a star", the command "apply transfer"
  2107 replaces it with an equivalent one that mentions only standard types.
  2108 To be successful, all free variables must have standard types; non-
  2109 standard variables must have explicit universal quantifiers.
  2110 
  2111 * Hyperreal: A theory of Taylor series.
  2112 
  2113 
  2114 *** HOLCF ***
  2115 
  2116 * Discontinued special version of 'constdefs' (which used to support
  2117 continuous functions) in favor of the general Pure one with full
  2118 type-inference.
  2119 
  2120 * New simplification procedure for solving continuity conditions; it
  2121 is much faster on terms with many nested lambda abstractions (cubic
  2122 instead of exponential time).
  2123 
  2124 * New syntax for domain package: selector names are now optional.
  2125 Parentheses should be omitted unless argument is lazy, for example:
  2126 
  2127   domain 'a stream = cons "'a" (lazy "'a stream")
  2128 
  2129 * New command 'fixrec' for defining recursive functions with pattern
  2130 matching; defining multiple functions with mutual recursion is also
  2131 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2132 sinr, or any data constructor defined by the domain package. The given
  2133 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2134 syntax and examples.
  2135 
  2136 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2137 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2138 but the proof obligation additionally includes an admissibility
  2139 requirement. The packages generate instances of class cpo or pcpo,
  2140 with continuity and strictness theorems for Rep and Abs.
  2141 
  2142 * HOLCF: Many theorems have been renamed according to a more standard naming
  2143 scheme (INCOMPATIBILITY):
  2144 
  2145   foo_inject:  "foo$x = foo$y ==> x = y"
  2146   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2147   foo_less:    "(foo$x << foo$y) = (x << y)"
  2148   foo_strict:  "foo$UU = UU"
  2149   foo_defined: "... ==> foo$x ~= UU"
  2150   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2151 
  2152 
  2153 *** ZF ***
  2154 
  2155 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2156 including the First Isomorphism Theorem (on quotienting by the kernel
  2157 of a homomorphism).
  2158 
  2159 * ZF/Simplifier: install second copy of type solver that actually
  2160 makes use of TC rules declared to Isar proof contexts (or locales);
  2161 the old version is still required for ML proof scripts.
  2162 
  2163 
  2164 *** Cube ***
  2165 
  2166 * Converted to Isar theory format; use locales instead of axiomatic
  2167 theories.
  2168 
  2169 
  2170 *** ML ***
  2171 
  2172 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2173 for ||>, ||>>, |>>,
  2174 
  2175 * Pure/library.ML no longer defines its own option datatype, but uses
  2176 that of the SML basis, which has constructors NONE and SOME instead of
  2177 None and Some, as well as exception Option.Option instead of OPTION.
  2178 The functions the, if_none, is_some, is_none have been adapted
  2179 accordingly, while Option.map replaces apsome.
  2180 
  2181 * Pure/library.ML: the exception LIST has been given up in favour of
  2182 the standard exceptions Empty and Subscript, as well as
  2183 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2184 superceded by the standard hd and tl functions etc.
  2185 
  2186 A number of basic list functions are no longer exported to the ML
  2187 toplevel, as they are variants of predefined functions.  The following
  2188 suggests how one can translate existing code:
  2189 
  2190     rev_append xs ys = List.revAppend (xs, ys)
  2191     nth_elem (i, xs) = List.nth (xs, i)
  2192     last_elem xs = List.last xs
  2193     flat xss = List.concat xss
  2194     seq fs = List.app fs
  2195     partition P xs = List.partition P xs
  2196     mapfilter f xs = List.mapPartial f xs
  2197 
  2198 * Pure/library.ML: several combinators for linear functional
  2199 transformations, notably reverse application and composition:
  2200 
  2201   x |> f                f #> g
  2202   (x, y) |-> f          f #-> g
  2203 
  2204 * Pure/library.ML: introduced/changed precedence of infix operators:
  2205 
  2206   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2207   infix 2 ?;
  2208   infix 3 o oo ooo oooo;
  2209   infix 4 ~~ upto downto;
  2210 
  2211 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2212 infix operators.
  2213 
  2214 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2215 fold_map support linear functional transformations and nesting.  For
  2216 example:
  2217 
  2218   fold f [x1, ..., xN] y =
  2219     y |> f x1 |> ... |> f xN
  2220 
  2221   (fold o fold) f [xs1, ..., xsN] y =
  2222     y |> fold f xs1 |> ... |> fold f xsN
  2223 
  2224   fold f [x1, ..., xN] =
  2225     f x1 #> ... #> f xN
  2226 
  2227   (fold o fold) f [xs1, ..., xsN] =
  2228     fold f xs1 #> ... #> fold f xsN
  2229 
  2230 * Pure/library.ML: the following selectors on type 'a option are
  2231 available:
  2232 
  2233   the:               'a option -> 'a  (*partial*)
  2234   these:             'a option -> 'a  where 'a = 'b list
  2235   the_default: 'a -> 'a option -> 'a
  2236   the_list:          'a option -> 'a list
  2237 
  2238 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2239 basic operations for association lists, following natural argument
  2240 order; moreover the explicit equality predicate passed here avoids
  2241 potentially expensive polymorphic runtime equality checks.
  2242 The old functions may be expressed as follows:
  2243 
  2244   assoc = uncurry (AList.lookup (op =))
  2245   assocs = these oo AList.lookup (op =)
  2246   overwrite = uncurry (AList.update (op =)) o swap
  2247 
  2248 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2249 
  2250   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2251   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2252 
  2253 replacing make_keylist and keyfilter (occassionally used)
  2254 Naive rewrites:
  2255 
  2256   make_keylist = AList.make
  2257   keyfilter = AList.find (op =)
  2258 
  2259 * eq_fst and eq_snd now take explicit equality parameter, thus
  2260   avoiding eqtypes. Naive rewrites:
  2261 
  2262     eq_fst = eq_fst (op =)
  2263     eq_snd = eq_snd (op =)
  2264 
  2265 * Removed deprecated apl and apr (rarely used).
  2266   Naive rewrites:
  2267 
  2268     apl (n, op) =>>= curry op n
  2269     apr (op, m) =>>= fn n => op (n, m)
  2270 
  2271 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2272 provides a reasonably efficient light-weight implementation of sets as
  2273 lists.
  2274 
  2275 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2276 few new operations; existing lookup and update are now curried to
  2277 follow natural argument order (for use with fold etc.);
  2278 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2279 
  2280 * Pure/General: output via the Isabelle channels of
  2281 writeln/warning/error etc. is now passed through Output.output, with a
  2282 hook for arbitrary transformations depending on the print_mode
  2283 (cf. Output.add_mode -- the first active mode that provides a output
  2284 function wins).  Already formatted output may be embedded into further
  2285 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2286 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2287 accommodate easy composition of diagnostic messages etc.  Programmers
  2288 rarely need to care about Output.output or Output.raw at all, with
  2289 some notable exceptions: Output.output is required when bypassing the
  2290 standard channels (writeln etc.), or in token translations to produce
  2291 properly formatted results; Output.raw is required when capturing
  2292 already output material that will eventually be presented to the user
  2293 a second time.  For the default print mode, both Output.output and
  2294 Output.raw have no effect.
  2295 
  2296 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2297 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2298 cumulative results are displayed at the end of a batch session.
  2299 
  2300 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2301 replaced by File.platform_path and File.shell_path (with appropriate
  2302 hooks).  This provides a clean interface for unusual systems where the
  2303 internal and external process view of file names are different.
  2304 
  2305 * Pure: more efficient orders for basic syntactic entities: added
  2306 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2307 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2308 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2309 orders now -- potential INCOMPATIBILITY for code that depends on a
  2310 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2311 Library.sort_strings on result).
  2312 
  2313 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2314 fold_types traverse types/terms from left to right, observing natural
  2315 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2316 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2317 
  2318 * Pure: name spaces have been refined, with significant changes of the
  2319 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2320 to extern(_table).  The plain name entry path is superceded by a
  2321 general 'naming' context, which also includes the 'policy' to produce
  2322 a fully qualified name and external accesses of a fully qualified
  2323 name; NameSpace.extend is superceded by context dependent
  2324 Sign.declare_name.  Several theory and proof context operations modify
  2325 the naming context.  Especially note Theory.restore_naming and
  2326 ProofContext.restore_naming to get back to a sane state; note that
  2327 Theory.add_path is no longer sufficient to recover from
  2328 Theory.absolute_path in particular.
  2329 
  2330 * Pure: new flags short_names (default false) and unique_names
  2331 (default true) for controlling output of qualified names.  If
  2332 short_names is set, names are printed unqualified.  If unique_names is
  2333 reset, the name prefix is reduced to the minimum required to achieve
  2334 the original result when interning again, even if there is an overlap
  2335 with earlier declarations.
  2336 
  2337 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2338 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2339 (useful for printing error messages).  INCOMPATIBILITY.
  2340 
  2341 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2342 Theory.theory are now identified, referring to the universal
  2343 Context.theory (see Pure/context.ML).  Actual signature and theory
  2344 content is managed as theory data.  The old code and interfaces were
  2345 spread over many files and structures; the new arrangement introduces
  2346 considerable INCOMPATIBILITY to gain more clarity:
  2347 
  2348   Context -- theory management operations (name, identity, inclusion,
  2349     parents, ancestors, merge, etc.), plus generic theory data;
  2350 
  2351   Sign -- logical signature and syntax operations (declaring consts,
  2352     types, etc.), plus certify/read for common entities;
  2353 
  2354   Theory -- logical theory operations (stating axioms, definitions,
  2355     oracles), plus a copy of logical signature operations (consts,
  2356     types, etc.); also a few basic management operations (Theory.copy,
  2357     Theory.merge, etc.)
  2358 
  2359 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2360 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2361 for convenience -- they merely return the theory.
  2362 
  2363 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2364 
  2365 * Pure: the Isar proof context type is already defined early in Pure
  2366 as Context.proof (note that ProofContext.context and Proof.context are
  2367 aliases, where the latter is the preferred name).  This enables other
  2368 Isabelle components to refer to that type even before Isar is present.
  2369 
  2370 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2371 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2372 any of these kinds.  For example, Sign.intern typeK is now
  2373 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2374 Theory.hide_types.  Also note that former
  2375 Theory.hide_classes/types/consts are now
  2376 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2377 internalize their arguments!  INCOMPATIBILITY.
  2378 
  2379 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2380 datatype thmref (with constructors Name and NameSelection) instead of
  2381 plain string -- INCOMPATIBILITY;
  2382 
  2383 * Pure: cases produced by proof methods specify options, where NONE
  2384 means to remove case bindings -- INCOMPATIBILITY in
  2385 (RAW_)METHOD_CASES.
  2386 
  2387 * Pure: the following operations retrieve axioms or theorems from a
  2388 theory node or theory hierarchy, respectively:
  2389 
  2390   Theory.axioms_of: theory -> (string * term) list
  2391   Theory.all_axioms_of: theory -> (string * term) list
  2392   PureThy.thms_of: theory -> (string * thm) list
  2393   PureThy.all_thms_of: theory -> (string * thm) list
  2394 
  2395 * Pure: print_tac now outputs the goal through the trace channel.
  2396 
  2397 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2398 Reference Toplevel.debug (default false) controls detailed printing
  2399 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2400 controls execution profiling -- set to 1 for time and 2 for space
  2401 (both increase the runtime).
  2402 
  2403 * Isar session: The initial use of ROOT.ML is now always timed,
  2404 i.e. the log will show the actual process times, in contrast to the
  2405 elapsed wall-clock time that the outer shell wrapper produces.
  2406 
  2407 * Simplifier: improved handling of bound variables (nameless
  2408 representation, avoid allocating new strings).  Simprocs that invoke
  2409 the Simplifier recursively should use Simplifier.inherit_bounds to
  2410 avoid local name clashes.  Failure to do so produces warnings
  2411 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2412 for further details.
  2413 
  2414 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2415 bindings for all theorems stored within a given theory; this may help
  2416 in porting non-Isar theories to Isar ones, while keeping ML proof
  2417 scripts for the time being.
  2418 
  2419 * ML operator HTML.with_charset specifies the charset begin used for
  2420 generated HTML files.  For example:
  2421 
  2422   HTML.with_charset "utf-8" use_thy "Hebrew";
  2423   HTML.with_charset "utf-8" use_thy "Chinese";
  2424 
  2425 
  2426 *** System ***
  2427 
  2428 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2429 isabelle, isatool etc.).
  2430 
  2431 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2432 isatool doc, isatool mkdir, display_drafts etc.).
  2433 
  2434 * isatool usedir: option -f allows specification of the ML file to be
  2435 used by Isabelle; default is ROOT.ML.
  2436 
  2437 * New isatool version outputs the version identifier of the Isabelle
  2438 distribution being used.
  2439 
  2440 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2441 (containing Boolean satisfiability problems) into Isabelle/HOL
  2442 theories.
  2443 
  2444 
  2445 
  2446 New in Isabelle2004 (April 2004)
  2447 --------------------------------
  2448 
  2449 *** General ***
  2450 
  2451 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2452   Replaces linorder.ML.
  2453 
  2454 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2455   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2456   (\<a>...\<z>), are now considered normal letters, and can therefore
  2457   be used anywhere where an ASCII letter (a...zA...Z) has until
  2458   now. COMPATIBILITY: This obviously changes the parsing of some
  2459   terms, especially where a symbol has been used as a binder, say
  2460   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2461   as an identifier.  Fix it by inserting a space around former
  2462   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2463   existing theory and ML files.
  2464 
  2465 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2466 
  2467 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2468   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2469   a normal (but invisible) letter. For multiple letter subscripts repeat
  2470   \<^isub> like this: x\<^isub>1\<^isub>2.
  2471 
  2472 * Pure: There are now sub-/superscripts that can span more than one
  2473   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2474   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2475   superscript. The new control characters are not identifier parts.
  2476 
  2477 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2478   content of "..." to the latex file instead of \isacntrl... . The "..."
  2479   may consist of any printable characters excluding the end bracket >.
  2480 
  2481 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2482   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2483   declare constants "final", which prevents their being given a definition
  2484   later.  It is useful for constants whose behaviour is fixed axiomatically
  2485   rather than definitionally, such as the meta-logic connectives.
  2486 
  2487 * Pure: 'instance' now handles general arities with general sorts
  2488   (i.e. intersections of classes),
  2489 
  2490 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2491   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2492   It can be changed to alter the colors/layout of generated pages.
  2493 
  2494 
  2495 *** Isar ***
  2496 
  2497 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2498   cut_tac, subgoal_tac and thin_tac:
  2499   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2500     locales are no longer forced to write Isar proof scripts.
  2501     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2502     emulations.
  2503   - INCOMPATIBILITY: names of variables to be instantiated may no
  2504     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2505     This is consistent with the instantiation attribute "where".
  2506 
  2507 * Attributes "where" and "of":
  2508   - Now take type variables of instantiated theorem into account when reading
  2509     the instantiation string.  This fixes a bug that caused instantiated
  2510     theorems to have too special types in some circumstances.
  2511   - "where" permits explicit instantiations of type variables.
  2512 
  2513 * Calculation commands "moreover" and "also" no longer interfere with
  2514   current facts ("this"), admitting arbitrary combinations with "then"
  2515   and derived forms.
  2516 
  2517 * Locales:
  2518   - Goal statements involving the context element "includes" no longer
  2519     generate theorems with internal delta predicates (those ending on
  2520     "_axioms") in the premise.
  2521     Resolve particular premise with <locale>.intro to obtain old form.
  2522   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2523     specification and "includes" elements in goal statement.
  2524   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2525     [intro?] and [elim?] (respectively) by default.
  2526   - Experimental command for instantiation of locales in proof contexts:
  2527         instantiate <label>[<attrs>]: <loc>
  2528     Instantiates locale <loc> and adds all its theorems to the current context
  2529     taking into account their attributes.  Label and attrs are optional
  2530     modifiers, like in theorem declarations.  If present, names of
  2531     instantiated theorems are qualified with <label>, and the attributes
  2532     <attrs> are applied after any attributes these theorems might have already.
  2533       If the locale has assumptions, a chained fact of the form
  2534     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2535     are derived.  The command does not support old-style locales declared
  2536     with "locale (open)".
  2537       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2538 
  2539 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2540   (Isar) contexts.
  2541 
  2542 
  2543 *** HOL ***
  2544 
  2545 * Proof import: new image HOL4 contains the imported library from
  2546   the HOL4 system with about 2500 theorems. It is imported by
  2547   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2548   can be used like any other Isabelle image.  See
  2549   HOL/Import/HOL/README for more information.
  2550 
  2551 * Simplifier:
  2552   - Much improved handling of linear and partial orders.
  2553     Reasoners for linear and partial orders are set up for type classes
  2554     "linorder" and "order" respectively, and are added to the default simpset
  2555     as solvers.  This means that the simplifier can build transitivity chains
  2556     to solve goals from the assumptions.
  2557   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2558     of blast or auto after simplification become unnecessary because the goal
  2559     is solved by simplification already.
  2560 
  2561 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2562     all proved in axiomatic type classes for semirings, rings and fields.
  2563 
  2564 * Numerics:
  2565   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2566     now formalized using the Ring_and_Field theory mentioned above.
  2567   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2568     than before, because now they are set up once in a generic manner.
  2569   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2570     Look for the general versions in Ring_and_Field (and Power if they concern
  2571     exponentiation).
  2572 
  2573 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2574 
  2575 * Records:
  2576   - Record types are now by default printed with their type abbreviation
  2577     instead of the list of all field types. This can be configured via
  2578     the reference "print_record_type_abbr".
  2579   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2580     (not enabled by default).
  2581   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2582     EX x. x = sel r to True (not enabled by default).
  2583   - Tactic "record_split_simp_tac" to split and simplify records added.
  2584 
  2585 * 'specification' command added, allowing for definition by
  2586   specification.  There is also an 'ax_specification' command that
  2587   introduces the new constants axiomatically.
  2588 
  2589 * arith(_tac) is now able to generate counterexamples for reals as well.
  2590 
  2591 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2592 
  2593 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2594   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2595 
  2596 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2597   matrix theory to linear programming.
  2598 
  2599 * Unions and Intersections:
  2600   The latex output syntax of UN and INT has been changed
  2601   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2602   i.e. the index formulae has become a subscript.
  2603   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2604 
  2605 * Unions and Intersections over Intervals:
  2606   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2607   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2608   like in normal math, and corresponding versions for < and for intersection.
  2609 
  2610 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2611   lexicographic dictonary ordering has been added as "lexord".
  2612 
  2613 * ML: the legacy theory structures Int and List have been removed. They had
  2614   conflicted with ML Basis Library structures having the same names.
  2615 
  2616 * 'refute' command added to search for (finite) countermodels.  Only works
  2617   for a fragment of HOL.  The installation of an external SAT solver is
  2618   highly recommended.  See "HOL/Refute.thy" for details.
  2619 
  2620 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2621   formulae under an assignment of free variables to random values.
  2622   In contrast to 'refute', it can deal with inductive datatypes,
  2623   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2624   for examples.
  2625 
  2626 
  2627 *** HOLCF ***
  2628 
  2629 * Streams now come with concatenation and are part of the HOLCF image
  2630 
  2631 
  2632 
  2633 New in Isabelle2003 (May 2003)
  2634 ------------------------------
  2635 
  2636 *** General ***
  2637 
  2638 * Provers/simplifier:
  2639 
  2640   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2641     Assumptions are now subject to complete mutual simplification,
  2642     not just from left to right. The simplifier now preserves
  2643     the order of assumptions.
  2644 
  2645     Potential INCOMPATIBILITY:
  2646 
  2647     -- simp sometimes diverges where the old version did
  2648        not, e.g. invoking simp on the goal
  2649 
  2650         [| P (f x); y = x; f x = f y |] ==> Q
  2651 
  2652        now gives rise to the infinite reduction sequence
  2653 
  2654         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2655 
  2656        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2657        kind of problem.
  2658 
  2659     -- Tactics combining classical reasoner and simplification (such as auto)
  2660        are also affected by this change, because many of them rely on
  2661        simp. They may sometimes diverge as well or yield a different numbers
  2662        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2663        in case of problems. Sometimes subsequent calls to the classical
  2664        reasoner will fail because a preceeding call to the simplifier too
  2665        eagerly simplified the goal, e.g. deleted redundant premises.
  2666 
  2667   - The simplifier trace now shows the names of the applied rewrite rules
  2668 
  2669   - You can limit the number of recursive invocations of the simplifier
  2670     during conditional rewriting (where the simplifie tries to solve the
  2671     conditions before applying the rewrite rule):
  2672     ML "simp_depth_limit := n"
  2673     where n is an integer. Thus you can force termination where previously
  2674     the simplifier would diverge.
  2675 
  2676   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2677 
  2678   - No longer aborts on failed congruence proof.  Instead, the
  2679     congruence is ignored.
  2680 
  2681 * Pure: New generic framework for extracting programs from constructive
  2682   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2683   as HOL/Extraction for some case studies.
  2684 
  2685 * Pure: The main goal of the proof state is no longer shown by default, only
  2686 the subgoals. This behaviour is controlled by a new flag.
  2687    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2688 (ML: Proof.show_main_goal).
  2689 
  2690 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2691 rules whose conclusion matches subgoal 1:
  2692       PG menu: Isabelle/Isar -> Show me -> matching rules
  2693 The rules are ordered by how closely they match the subgoal.
  2694 In particular, rules that solve a subgoal outright are displayed first
  2695 (or rather last, the way they are printed).
  2696 (ML: ProofGeneral.print_intros())
  2697 
  2698 * Pure: New flag trace_unify_fail causes unification to print
  2699 diagnostic information (PG: in trace buffer) when it fails. This is
  2700 useful for figuring out why single step proofs like rule, erule or
  2701 assumption failed.
  2702 
  2703 * Pure: Locale specifications now produce predicate definitions
  2704 according to the body of text (covering assumptions modulo local
  2705 definitions); predicate "loc_axioms" covers newly introduced text,
  2706 while "loc" is cumulative wrt. all included locale expressions; the
  2707 latter view is presented only on export into the global theory
  2708 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2709 on the old view without predicates;
  2710 
  2711 * Pure: predefined locales "var" and "struct" are useful for sharing
  2712 parameters (as in CASL, for example); just specify something like
  2713 ``var x + var y + struct M'' as import;
  2714 
  2715 * Pure: improved thms_containing: proper indexing of facts instead of
  2716 raw theorems; check validity of results wrt. current name space;
  2717 include local facts of proof configuration (also covers active
  2718 locales), cover fixed variables in index; may use "_" in term
  2719 specification; an optional limit for the number of printed facts may
  2720 be given (the default is 40);
  2721 
  2722 * Pure: disallow duplicate fact bindings within new-style theory files
  2723 (batch-mode only);
  2724 
  2725 * Provers: improved induct method: assumptions introduced by case
  2726 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2727 the goal statement); "foo" still refers to all facts collectively;
  2728 
  2729 * Provers: the function blast.overloaded has been removed: all constants
  2730 are regarded as potentially overloaded, which improves robustness in exchange
  2731 for slight decrease in efficiency;
  2732 
  2733 * Provers/linorder: New generic prover for transitivity reasoning over
  2734 linear orders.  Note: this prover is not efficient!
  2735 
  2736 * Isar: preview of problems to finish 'show' now produce an error
  2737 rather than just a warning (in interactive mode);
  2738 
  2739 
  2740 *** HOL ***
  2741 
  2742 * arith(_tac)
  2743 
  2744  - Produces a counter example if it cannot prove a goal.
  2745    Note that the counter example may be spurious if the goal is not a formula
  2746    of quantifier-free linear arithmetic.
  2747    In ProofGeneral the counter example appears in the trace buffer.
  2748 
  2749  - Knows about div k and mod k where k is a numeral of type nat or int.
  2750 
  2751  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2752    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2753    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2754 
  2755 * simp's arithmetic capabilities have been enhanced a bit: it now
  2756 takes ~= in premises into account (by performing a case split);
  2757 
  2758 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2759 are distributed over a sum of terms;
  2760 
  2761 * New tactic "trans_tac" and method "trans" instantiate
  2762 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2763 "<=", "<" and "=").
  2764 
  2765 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2766 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2767 
  2768 * 'typedef' command has new option "open" to suppress the set
  2769 definition;
  2770 
  2771 * functions Min and Max on finite sets have been introduced (theory
  2772 Finite_Set);
  2773 
  2774 * attribute [symmetric] now works for relations as well; it turns
  2775 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2776 
  2777 * induct over a !!-quantified statement (say !!x1..xn):
  2778   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2779 
  2780 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2781 %x. None. Warning: empty_def now refers to the previously hidden definition
  2782 of the empty set.
  2783 
  2784 * Algebra: formalization of classical algebra.  Intended as base for
  2785 any algebraic development in Isabelle.  Currently covers group theory
  2786 (up to Sylow's theorem) and ring theory (Universal Property of
  2787 Univariate Polynomials).  Contributions welcome;
  2788 
  2789 * GroupTheory: deleted, since its material has been moved to Algebra;
  2790 
  2791 * Complex: new directory of the complex numbers with numeric constants,
  2792 nonstandard complex numbers, and some complex analysis, standard and
  2793 nonstandard (Jacques Fleuriot);
  2794 
  2795 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2796 
  2797 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2798 Fleuriot);
  2799 
  2800 * Real/HahnBanach: updated and adapted to locales;
  2801 
  2802 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2803 Gray and Kramer);
  2804 
  2805 * UNITY: added the Meier-Sanders theory of progress sets;
  2806 
  2807 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2808 as abstract algorithms, instantiated to the JVM;
  2809 
  2810 * Bali: Java source language formalization. Type system, operational
  2811 semantics, axiomatic semantics. Supported language features:
  2812 classes, interfaces, objects,virtual methods, static methods,
  2813 static/instance fields, arrays, access modifiers, definite
  2814 assignment, exceptions.
  2815 
  2816 
  2817 *** ZF ***
  2818 
  2819 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2820 universe, etc.);
  2821 
  2822 * Main ZF: virtually all theories converted to new-style format;
  2823 
  2824 
  2825 *** ML ***
  2826 
  2827 * Pure: Tactic.prove provides sane interface for internal proofs;
  2828 omits the infamous "standard" operation, so this is more appropriate
  2829 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2830 
  2831 * Pure: improved error reporting of simprocs;
  2832 
  2833 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2834 up simprocs;
  2835 
  2836 
  2837 *** Document preparation ***
  2838 
  2839 * uses \par instead of \\ for line breaks in theory text. This may
  2840 shift some page breaks in large documents. To get the old behaviour
  2841 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2842 
  2843 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2844 other packages
  2845 
  2846 * \<euro> now needs package babel/greek instead of marvosym (which
  2847 broke \Rightarrow)
  2848 
  2849 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2850 textcomp package)
  2851 
  2852 
  2853 
  2854 New in Isabelle2002 (March 2002)
  2855 --------------------------------
  2856 
  2857 *** Document preparation ***
  2858 
  2859 * greatly simplified document preparation setup, including more
  2860 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2861 instructive isatool mkdir; users should basically be able to get
  2862 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2863 users may run a separate document processing stage manually like this:
  2864 "isatool usedir -D output HOL Test && isatool document Test/output";
  2865 
  2866 * theory dependency graph may now be incorporated into documents;
  2867 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2868 with \includegraphics of LaTeX;
  2869 
  2870 * proper spacing of consecutive markup elements, especially text
  2871 blocks after section headings;
  2872 
  2873 * support bold style (for single symbols only), input syntax is like
  2874 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2875 
  2876 * \<bullet> is now output as bold \cdot by default, which looks much
  2877 better in printed text;
  2878 
  2879 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2880 note that these symbols are currently unavailable in Proof General /
  2881 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2882 
  2883 * isatool latex no longer depends on changed TEXINPUTS, instead
  2884 isatool document copies the Isabelle style files to the target
  2885 location;
  2886 
  2887 
  2888 *** Isar ***
  2889 
  2890 * Pure/Provers: improved proof by cases and induction;
  2891   - 'case' command admits impromptu naming of parameters (such as
  2892     "case (Suc n)");
  2893   - 'induct' method divinates rule instantiation from the inductive
  2894     claim; no longer requires excessive ?P bindings for proper
  2895     instantiation of cases;
  2896   - 'induct' method properly enumerates all possibilities of set/type
  2897     rules; as a consequence facts may be also passed through *type*
  2898     rules without further ado;
  2899   - 'induct' method now derives symbolic cases from the *rulified*
  2900     rule (before it used to rulify cases stemming from the internal
  2901     atomized version); this means that the context of a non-atomic
  2902     statement becomes is included in the hypothesis, avoiding the
  2903     slightly cumbersome show "PROP ?case" form;
  2904   - 'induct' may now use elim-style induction rules without chaining
  2905     facts, using ``missing'' premises from the goal state; this allows
  2906     rules stemming from inductive sets to be applied in unstructured
  2907     scripts, while still benefitting from proper handling of non-atomic
  2908     statements; NB: major inductive premises need to be put first, all
  2909     the rest of the goal is passed through the induction;
  2910   - 'induct' proper support for mutual induction involving non-atomic
  2911     rule statements (uses the new concept of simultaneous goals, see
  2912     below);
  2913   - append all possible rule selections, but only use the first
  2914     success (no backtracking);
  2915   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2916   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2917   - added 'print_induct_rules' (covered by help item in recent Proof
  2918     General versions);
  2919   - moved induct/cases attributes to Pure, methods to Provers;
  2920   - generic method setup instantiated for FOL and HOL;
  2921 
  2922 * Pure: support multiple simultaneous goal statements, for example
  2923 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2924 meta-level mechanism, this acts as if several individual goals had
  2925 been stated separately; in particular common proof methods need to be
  2926 repeated in order to cover all claims; note that a single elimination
  2927 step is *not* sufficient to establish the two conjunctions, so this
  2928 fails:
  2929 
  2930   assume "A & B" then have A and B ..   (*".." fails*)
  2931 
  2932 better use "obtain" in situations as above; alternative refer to
  2933 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2934 
  2935 * Pure: proper integration with ``locales''; unlike the original
  2936 version by Florian Kammller, Isar locales package high-level proof
  2937 contexts rather than raw logical ones (e.g. we admit to include
  2938 attributes everywhere); operations on locales include merge and
  2939 rename; support for implicit arguments (``structures''); simultaneous
  2940 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2941 some examples;
  2942 
  2943 * Pure: the following commands have been ``localized'', supporting a
  2944 target locale specification "(in name)": 'lemma', 'theorem',
  2945 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2946 stored both within the locale and at the theory level (exported and
  2947 qualified by the locale name);
  2948 
  2949 * Pure: theory goals may now be specified in ``long'' form, with
  2950 ad-hoc contexts consisting of arbitrary locale elements. for example
  2951 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2952 definitions may be given, too); the result is a meta-level rule with
  2953 the context elements being discharged in the obvious way;
  2954 
  2955 * Pure: new proof command 'using' allows to augment currently used
  2956 facts after a goal statement ('using' is syntactically analogous to
  2957 'apply', but acts on the goal's facts only); this allows chained facts
  2958 to be separated into parts given before and after a claim, as in
  2959 ``from a and b have C using d and e <proof>'';
  2960 
  2961 * Pure: renamed "antecedent" case to "rule_context";
  2962 
  2963 * Pure: new 'judgment' command records explicit information about the
  2964 object-logic embedding (used by several tools internally); no longer
  2965 use hard-wired "Trueprop";
  2966 
  2967 * Pure: added 'corollary' command;
  2968 
  2969 * Pure: fixed 'token_translation' command;
  2970 
  2971 * Pure: removed obsolete 'exported' attribute;
  2972 
  2973 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2974 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2975 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2976 
  2977 * Pure: method 'atomize' presents local goal premises as object-level
  2978 statements (atomic meta-level propositions); setup controlled via
  2979 rewrite rules declarations of 'atomize' attribute; example
  2980 application: 'induct' method with proper rule statements in improper
  2981 proof *scripts*;
  2982 
  2983 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2984 now consider the syntactic context of assumptions, giving a better
  2985 chance to get type-inference of the arguments right (this is
  2986 especially important for locales);
  2987 
  2988 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2989 mode;
  2990 
  2991 * Pure/obtain: the formal conclusion "thesis", being marked as
  2992 ``internal'', may no longer be reference directly in the text;
  2993 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2994 situations;
  2995 
  2996 * Pure: generic 'sym' attribute which declares a rule both as pure
  2997 'elim?' and for the 'symmetric' operation;
  2998 
  2999 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3000 text; the fixed correlation with particular command syntax has been
  3001 discontinued;
  3002 
  3003 * Pure: new method 'rules' is particularly well-suited for proof
  3004 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3005 but often produces more compact proof terms with less detours;
  3006 
  3007 * Pure/Provers/classical: simplified integration with pure rule
  3008 attributes and methods; the classical "intro?/elim?/dest?"
  3009 declarations coincide with the pure ones; the "rule" method no longer
  3010 includes classically swapped intros; "intro" and "elim" methods no
  3011 longer pick rules from the context; also got rid of ML declarations
  3012 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3013 INCOMPATIBILITY;
  3014 
  3015 * Provers/classical: attribute 'swapped' produces classical inversions
  3016 of introduction rules;
  3017 
  3018 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3019 rules instead of full simplifier context; 'iff' attribute handles
  3020 conditional rules;
  3021 
  3022 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3023 
  3024 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3025 "(permissive)" option to recover old behavior;
  3026 
  3027 * HOL: 'inductive' no longer features separate (collective) attributes
  3028 for 'intros' (was found too confusing);
  3029 
  3030 * HOL: properly declared induction rules less_induct and
  3031 wf_induct_rule;
  3032 
  3033 
  3034 *** HOL ***
  3035 
  3036 * HOL: moved over to sane numeral syntax; the new policy is as
  3037 follows:
  3038 
  3039   - 0 and 1 are polymorphic constants, which are defined on any
  3040   numeric type (nat, int, real etc.);
  3041 
  3042   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3043   binary representation internally;
  3044 
  3045   - type nat has special constructor Suc, and generally prefers Suc 0
  3046   over 1::nat and Suc (Suc 0) over 2::nat;
  3047 
  3048 This change may cause significant problems of INCOMPATIBILITY; here
  3049 are some hints on converting existing sources:
  3050 
  3051   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3052   entities, so expressions involving "-" (unary or binary minus) need
  3053   to be spaced properly;
  3054 
  3055   - existing occurrences of "1" may need to be constraint "1::nat" or
  3056   even replaced by Suc 0; similar for old "2";
  3057 
  3058   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3059 
  3060   - remove all special provisions on numerals in proofs;
  3061 
  3062 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3063 representation (depends on bin_arith_simps in the default context);
  3064 
  3065 * HOL: symbolic syntax for x^2 (numeral 2);
  3066 
  3067 * HOL: the class of all HOL types is now called "type" rather than
  3068 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3069 in axclass/classes, instance/arities, and (usually rare) occurrences
  3070 in typings (of consts etc.); internally the class is called
  3071 "HOL.type", ML programs should refer to HOLogic.typeS;
  3072 
  3073 * HOL/record package improvements:
  3074   - new derived operations "fields" to build a partial record section,
  3075     "extend" to promote a fixed record to a record scheme, and
  3076     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3077     declared as simp by default;
  3078   - shared operations ("more", "fields", etc.) now need to be always
  3079     qualified) --- potential INCOMPATIBILITY;
  3080   - removed "make_scheme" operations (use "make" with "extend") --
  3081     INCOMPATIBILITY;
  3082   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3083   - provides cases/induct rules for use with corresponding Isar
  3084     methods (for concrete records, record schemes, concrete more
  3085     parts, and schematic more parts -- in that order);
  3086   - internal definitions directly based on a light-weight abstract
  3087     theory of product types over typedef rather than datatype;
  3088 
  3089 * HOL: generic code generator for generating executable ML code from
  3090 specifications; specific support for HOL constructs such as inductive
  3091 datatypes and sets, as well as recursive functions; can be invoked
  3092 via 'generate_code' theory section;
  3093 
  3094 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3095 
  3096 * HOL: consolidated and renamed several theories.  In particular:
  3097         Ord.thy has been absorbed into HOL.thy
  3098         String.thy has been absorbed into List.thy
  3099 
  3100 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3101 (beware of argument permutation!);
  3102 
  3103 * HOL: linorder_less_split superseded by linorder_cases;
  3104 
  3105 * HOL/List: "nodups" renamed to "distinct";
  3106 
  3107 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3108 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3109   - Ex_def has changed, now need to use some_eq_ex
  3110 
  3111 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3112 in this (rare) case use:
  3113 
  3114   delSWrapper "split_all_tac"
  3115   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3116 
  3117 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3118 MAY FAIL;
  3119 
  3120 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3121 Isabelle's type classes, ^ on functions and relations has too general
  3122 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3123 necessary to attach explicit type constraints;
  3124 
  3125 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3126 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3127 renamed accordingly (eg "compI" -> "rel_compI").
  3128 
  3129 * HOL: syntax translations now work properly with numerals and records
  3130 expressions;
  3131 
  3132 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3133 of "lam" -- INCOMPATIBILITY;
  3134 
  3135 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3136 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3137 renamed "Product_Type.unit";
  3138 
  3139 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3140 
  3141 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3142 the "cases" method);
  3143 
  3144 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3145 Florian Kammller);
  3146 
  3147 * HOL/IMP: updated and converted to new-style theory format; several
  3148 parts turned into readable document, with proper Isar proof texts and
  3149 some explanations (by Gerwin Klein);
  3150 
  3151 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3152 
  3153 * HOL-Hyperreal is now a logic image;
  3154 
  3155 
  3156 *** HOLCF ***
  3157 
  3158 * Isar: consts/constdefs supports mixfix syntax for continuous
  3159 operations;
  3160 
  3161 * Isar: domain package adapted to new-style theory format, e.g. see
  3162 HOLCF/ex/Dnat.thy;
  3163 
  3164 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3165 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3166 lift.induct_tac, always use UU instead of Undef;
  3167 
  3168 * HOLCF/IMP: updated and converted to new-style theory;
  3169 
  3170 
  3171 *** ZF ***
  3172 
  3173 * Isar: proper integration of logic-specific tools and packages,
  3174 including theory commands '(co)inductive', '(co)datatype',
  3175 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3176 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3177 
  3178 * theory Main no longer includes AC; for the Axiom of Choice, base
  3179 your theory on Main_ZFC;
  3180 
  3181 * the integer library now covers quotients and remainders, with many
  3182 laws relating division to addition, multiplication, etc.;
  3183 
  3184 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3185 typeless version of the formalism;
  3186 
  3187 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3188 format;
  3189 
  3190 * ZF/Induct: new directory for examples of inductive definitions,
  3191 including theory Multiset for multiset orderings; converted to
  3192 new-style theory format;
  3193 
  3194 * ZF: many new theorems about lists, ordinals, etc.;
  3195 
  3196 
  3197 *** General ***
  3198 
  3199 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3200 variable proof controls level of detail: 0 = no proofs (only oracle
  3201 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3202 also ref manual for further ML interfaces;
  3203 
  3204 * Pure/axclass: removed obsolete ML interface
  3205 goal_subclass/goal_arity;
  3206 
  3207 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3208 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3209 separate tokens, so expressions involving minus need to be spaced
  3210 properly;
  3211 
  3212 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3213 rather than "infixl" or "infixr";
  3214 
  3215 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3216 sort constraint specifications in type inference; e.g. "x::_::foo"
  3217 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3218 type variable);
  3219 
  3220 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3221 control output of nested => (types); the default behavior is
  3222 "type_brackets";
  3223 
  3224 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3225 tokens into AST constants;
  3226 
  3227 * Pure/syntax: prefer later declarations of translations and print
  3228 translation functions; potential INCOMPATIBILITY: need to reverse
  3229 multiple declarations for same syntax element constant;
  3230 
  3231 * Pure/show_hyps reset by default (in accordance to existing Isar
  3232 practice);
  3233 
  3234 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3235 addSafter;
  3236 
  3237 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3238 as well;
  3239 
  3240 * system: tested support for MacOS X; should be able to get Isabelle +
  3241 Proof General to work in a plain Terminal after installing Poly/ML
  3242 (e.g. from the Isabelle distribution area) and GNU bash alone
  3243 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3244 support requires further installations, e.g. from
  3245 http://fink.sourceforge.net/);
  3246 
  3247 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3248 
  3249 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3250 of 40 MB), cf. ML_OPTIONS;
  3251 
  3252 * system: Proof General keywords specification is now part of the
  3253 Isabelle distribution (see etc/isar-keywords.el);
  3254 
  3255 * system: support for persistent Proof General sessions (refrain from
  3256 outdating all loaded theories on startup); user may create writable
  3257 logic images like this: ``isabelle -q HOL Test'';
  3258 
  3259 * system: smart selection of Isabelle process versus Isabelle
  3260 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3261 run both "isabelle" and "Isabelle" even if file names are badly
  3262 damaged (executable inspects the case of the first letter of its own
  3263 name); added separate "isabelle-process" and "isabelle-interface";
  3264 
  3265 * system: refrain from any attempt at filtering input streams; no
  3266 longer support ``8bit'' encoding of old isabelle font, instead proper
  3267 iso-latin characters may now be used; the related isatools
  3268 "symbolinput" and "nonascii" have disappeared as well;
  3269 
  3270 * system: removed old "xterm" interface (the print modes "xterm" and
  3271 "xterm_color" are still available for direct use in a suitable
  3272 terminal);
  3273 
  3274 
  3275 
  3276 New in Isabelle99-2 (February 2001)
  3277 -----------------------------------
  3278 
  3279 *** Overview of INCOMPATIBILITIES ***
  3280 
  3281 * HOL: please note that theories in the Library and elsewhere often use the
  3282 new-style (Isar) format; to refer to their theorems in an ML script you must
  3283 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3284 
  3285 * HOL: inductive package no longer splits induction rule aggressively,
  3286 but only as far as specified by the introductions given; the old
  3287 format may be recovered via ML function complete_split_rule or attribute
  3288 'split_rule (complete)';
  3289 
  3290 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3291 gfp_Tarski to gfp_unfold;
  3292 
  3293 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3294 
  3295 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3296 relation); infix "^^" has been renamed "``"; infix "``" has been
  3297 renamed "`"; "univalent" has been renamed "single_valued";
  3298 
  3299 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3300 operation;
  3301 
  3302 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3303 
  3304 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3305 
  3306 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3307 consequence, it is no longer monotonic wrt. the local goal context
  3308 (which is now passed through the inductive cases);
  3309 
  3310 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3311 \<gg> to \<ggreater>;
  3312 
  3313 
  3314 *** Document preparation ***
  3315 
  3316 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3317 available: are "it" for near math-mode best-style output, "sl" for
  3318 slanted text style, and "tt" for plain type-writer; if no
  3319 \isabellestyle command is given, output is according to slanted
  3320 type-writer);
  3321 
  3322 * support sub/super scripts (for single symbols only), input syntax is
  3323 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3324 
  3325 * some more standard symbols; see Appendix A of the system manual for
  3326 the complete list of symbols defined in isabellesym.sty;
  3327 
  3328 * improved isabelle style files; more abstract symbol implementation
  3329 (should now use \isamath{...} and \isatext{...} in custom symbol
  3330 definitions);
  3331 
  3332 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3333 state; Note that presentation of goal states does not conform to
  3334 actual human-readable proof documents.  Please do not include goal
  3335 states into document output unless you really know what you are doing!
  3336 
  3337 * proper indentation of antiquoted output with proportional LaTeX
  3338 fonts;
  3339 
  3340 * no_document ML operator temporarily disables LaTeX document
  3341 generation;
  3342 
  3343 * isatool unsymbolize tunes sources for plain ASCII communication;
  3344 
  3345 
  3346 *** Isar ***
  3347 
  3348 * Pure: Isar now suffers initial goal statements to contain unbound
  3349 schematic variables (this does not conform to actual readable proof
  3350 documents, due to unpredictable outcome and non-compositional proof
  3351 checking); users who know what they are doing may use schematic goals
  3352 for Prolog-style synthesis of proven results;
  3353 
  3354 * Pure: assumption method (an implicit finishing) now handles actual
  3355 rules as well;
  3356 
  3357 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3358 initial goal, declare "that" only as Pure intro (only for single
  3359 steps); the "that" rule assumption may now be involved in implicit
  3360 finishing, thus ".." becomes a feasible for trivial obtains;
  3361 
  3362 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3363 instance proofs may be performed by "..";
  3364 
  3365 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3366 statements as well;
  3367 
  3368 * Pure: more robust selection of calculational rules;
  3369 
  3370 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3371 rule (as well as the assumption rule);
  3372 
  3373 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3374 lemmas, using the graph browser tool;
  3375 
  3376 * Pure: predict failure of "show" in interactive mode;
  3377 
  3378 * Pure: 'thms_containing' now takes actual terms as arguments;
  3379 
  3380 * HOL: improved method 'induct' --- now handles non-atomic goals
  3381 (potential INCOMPATIBILITY); tuned error handling;
  3382 
  3383 * HOL: cases and induct rules now provide explicit hints about the
  3384 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3385 any remaining facts are inserted into the goal verbatim;
  3386 
  3387 * HOL: local contexts (aka cases) may now contain term bindings as
  3388 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3389 the result to be shown in each case;
  3390 
  3391 * HOL: added 'recdef_tc' command;
  3392 
  3393 * isatool convert assists in eliminating legacy ML scripts;
  3394 
  3395 
  3396 *** HOL ***
  3397 
  3398 * HOL/Library: a collection of generic theories to be used together
  3399 with main HOL; the theory loader path already includes this directory
  3400 by default; the following existing theories have been moved here:
  3401 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3402 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3403 
  3404 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3405 modelling and verification task performed in Isabelle/HOL +
  3406 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3407 
  3408 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3409 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3410 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3411 'domain', this makes the theory consistent with mathematical
  3412 literature;
  3413 
  3414 * HOL basics: added overloaded operations "inverse" and "divide"
  3415 (infix "/"), syntax for generic "abs" operation, generic summation
  3416 operator \<Sum>;
  3417 
  3418 * HOL/typedef: simplified package, provide more useful rules (see also
  3419 HOL/subset.thy);
  3420 
  3421 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3422 now expressed as a proper nested rule (old-style tactic scripts may
  3423 require atomize_strip_tac to cope with non-atomic premises);
  3424 
  3425 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3426 to "split_conv" (old name still available for compatibility);
  3427 
  3428 * HOL: improved concrete syntax for strings (e.g. allows translation
  3429 rules with string literals);
  3430 
  3431 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3432  and Fleuriot's mechanization of analysis, including the transcendental
  3433  functions for the reals;
  3434 
  3435 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3436 
  3437 
  3438 *** CTT ***
  3439 
  3440 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3441 "lam" is displayed as TWO lambda-symbols
  3442 
  3443 * CTT: theory Main now available, containing everything (that is, Bool
  3444 and Arith);
  3445 
  3446 
  3447 *** General ***
  3448 
  3449 * Pure: the Simplifier has been implemented properly as a derived rule
  3450 outside of the actual kernel (at last!); the overall performance
  3451 penalty in practical applications is about 50%, while reliability of
  3452 the Isabelle inference kernel has been greatly improved;
  3453 
  3454 * print modes "brackets" and "no_brackets" control output of nested =>
  3455 (types) and ==> (props); the default behaviour is "brackets";
  3456 
  3457 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3458 as assumptions as well;
  3459 
  3460 * system: support Poly/ML 4.0;
  3461 
  3462 * system: isatool install handles KDE version 1 or 2;
  3463 
  3464 
  3465 
  3466 New in Isabelle99-1 (October 2000)
  3467 ----------------------------------
  3468 
  3469 *** Overview of INCOMPATIBILITIES ***
  3470 
  3471 * HOL: simplification of natural numbers is much changed; to partly
  3472 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3473 issue the following ML commands:
  3474 
  3475   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3476   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3477 
  3478 * HOL: simplification no longer dives into case-expressions; this is
  3479 controlled by "t.weak_case_cong" for each datatype t;
  3480 
  3481 * HOL: nat_less_induct renamed to less_induct;
  3482 
  3483 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3484 fixsome to patch .thy and .ML sources automatically;
  3485 
  3486   select_equality  -> some_equality
  3487   select_eq_Ex     -> some_eq_ex
  3488   selectI2EX       -> someI2_ex
  3489   selectI2         -> someI2
  3490   selectI          -> someI
  3491   select1_equality -> some1_equality
  3492   Eps_sym_eq       -> some_sym_eq_trivial
  3493   Eps_eq           -> some_eq_trivial
  3494 
  3495 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3496 
  3497 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3498 instead);
  3499 
  3500 * HOL: the recursion equations generated by 'recdef' are now called
  3501 f.simps instead of f.rules;
  3502 
  3503 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3504 
  3505 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3506 sometimes be needed;
  3507 
  3508 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3509 
  3510 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3511 
  3512 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3513 product is now "<*>" instead of "Times"; the lexicographic product is
  3514 now "<*lex*>" instead of "**";
  3515 
  3516 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3517 of main HOL, but was unused); better use HOL's datatype package;
  3518 
  3519 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3520 the old syntax may be recovered as follows:
  3521 
  3522   syntax (symbols)
  3523     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3524       (infixl "\\<oplus>" 100)
  3525 
  3526 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3527 
  3528 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3529 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3530 internally;
  3531 
  3532 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3533 changed from A/r to A//r;
  3534 
  3535 * ZF: new treatment of arithmetic (nat & int) may break some old
  3536 proofs;
  3537 
  3538 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3539 rulify -> rule_format, elimify -> elim_format, ...);
  3540 
  3541 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3542 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3543 should have to change intro!! to intro? only); replaced "delrule" by
  3544 "rule del";
  3545 
  3546 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3547 
  3548 * Provers: strengthened force_tac by using new first_best_tac;
  3549 
  3550 * LaTeX document preparation: several changes of isabelle.sty (see
  3551 lib/texinputs);
  3552 
  3553 
  3554 *** Document preparation ***
  3555 
  3556 * formal comments (text blocks etc.) in new-style theories may now
  3557 contain antiquotations of thm/prop/term/typ/text to be presented
  3558 according to latex print mode; concrete syntax is like this:
  3559 @{term[show_types] "f(x) = a + x"};
  3560 
  3561 * isatool mkdir provides easy setup of Isabelle session directories,
  3562 including proper document sources;
  3563 
  3564 * generated LaTeX sources are now deleted after successful run
  3565 (isatool document -c); may retain a copy somewhere else via -D option
  3566 of isatool usedir;
  3567 
  3568 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3569 style files, achieving self-contained LaTeX sources and simplifying
  3570 LaTeX debugging;
  3571 
  3572 * old-style theories now produce (crude) LaTeX output as well;
  3573 
  3574 * browser info session directories are now self-contained (may be put
  3575 on WWW server seperately); improved graphs of nested sessions; removed
  3576 graph for 'all sessions';
  3577 
  3578 * several improvements in isabelle style files; \isabellestyle{it}
  3579 produces fake math mode output; \isamarkupheader is now \section by
  3580 default; see lib/texinputs/isabelle.sty etc.;
  3581 
  3582 
  3583 *** Isar ***
  3584 
  3585 * Isar/Pure: local results and corresponding term bindings are now
  3586 subject to Hindley-Milner polymorphism (similar to ML); this
  3587 accommodates incremental type-inference very nicely;
  3588 
  3589 * Isar/Pure: new derived language element 'obtain' supports
  3590 generalized existence reasoning;
  3591 
  3592 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3593 support accumulation of results, without applying any rules yet;
  3594 useful to collect intermediate results without explicit name
  3595 references, and for use with transitivity rules with more than 2
  3596 premises;
  3597 
  3598 * Isar/Pure: scalable support for case-analysis type proofs: new
  3599 'case' language element refers to local contexts symbolically, as
  3600 produced by certain proof methods; internally, case names are attached
  3601 to theorems as "tags";
  3602 
  3603 * Isar/Pure: theory command 'hide' removes declarations from
  3604 class/type/const name spaces;
  3605 
  3606 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3607 indicate potential overloading;
  3608 
  3609 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3610 
  3611 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3612 "{a,b,c}" instead of {a,b,c};
  3613 
  3614 * Isar/Pure now provides its own version of intro/elim/dest
  3615 attributes; useful for building new logics, but beware of confusion
  3616 with the version in Provers/classical;
  3617 
  3618 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3619 case name 'antecedent';
  3620 
  3621 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3622 to the current context is now done automatically);
  3623 
  3624 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3625 for definining proof methods in ML;
  3626 
  3627 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3628 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3629 most cases, one should have to change intro!! to intro? only);
  3630 replaced "delrule" by "rule del";
  3631 
  3632 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3633 'symmetric' attribute (the latter supercedes [RS sym]);
  3634 
  3635 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3636 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3637 well (including splits);
  3638 
  3639 * Isar/Provers: Simplifier and Classical methods now support all kind
  3640 of modifiers used in the past, including 'cong', 'iff', etc.
  3641 
  3642 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3643 of Simplifier and Classical reasoner);
  3644 
  3645 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3646 now support named cases; major packages (inductive, datatype, primrec,
  3647 recdef) support case names and properly name parameters;
  3648 
  3649 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3650 monotonicity conditions are extracted to be proven at end of
  3651 calculations;
  3652 
  3653 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3654 method anyway;
  3655 
  3656 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3657 split_if split_if_asm; datatype package provides theorems foo.splits =
  3658 foo.split foo.split_asm for each datatype;
  3659 
  3660 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3661 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3662 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3663 use "(cases (simplified))" method in proper proof texts);
  3664 
  3665 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3666 
  3667 * Isar: names of theorems etc. may be natural numbers as well;
  3668 
  3669 * Isar: 'pr' command: optional arguments for goals_limit and
  3670 ProofContext.prems_limit; no longer prints theory contexts, but only
  3671 proof states;
  3672 
  3673 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3674 additional print modes to be specified; e.g. "pr(latex)" will print
  3675 proof state according to the Isabelle LaTeX style;
  3676 
  3677 * Isar: improved support for emulating tactic scripts, including proof
  3678 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3679 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3680 (for HOL datatypes);
  3681 
  3682 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3683 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3684 'proof method scripts' have to be in depth-first order;
  3685 
  3686 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3687 
  3688 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3689 should instead use individual commands for printing items
  3690 (print_commands, print_methods etc.);
  3691 
  3692 * Isar: added 'nothing' --- the empty list of theorems;
  3693 
  3694 
  3695 *** HOL ***
  3696 
  3697 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3698 corresponding virtual machine and a specification of its bytecode
  3699 verifier and a lightweight bytecode verifier, including proofs of
  3700 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3701 Cornelia Pusch (see also the homepage of project Bali at
  3702 http://isabelle.in.tum.de/Bali/);
  3703 
  3704 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3705 Clemens Ballarin;
  3706 
  3707 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3708 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3709 Rasmussen;
  3710 
  3711 * HOL/Lattice: fundamental concepts of lattice theory and order
  3712 structures, including duals, properties of bounds versus algebraic
  3713 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3714 Theorem for complete lattices etc.; may also serve as a demonstration
  3715 for abstract algebraic reasoning using axiomatic type classes, and
  3716 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3717 
  3718 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3719 von Oheimb;
  3720 
  3721 * HOL/IMPP: extension of IMP with local variables and mutually
  3722 recursive procedures, by David von Oheimb;
  3723 
  3724 * HOL/Lambda: converted into new-style theory and document;
  3725 
  3726 * HOL/ex/Multiquote: example of multiple nested quotations and
  3727 anti-quotations -- basically a generalized version of de-Bruijn
  3728 representation; very useful in avoiding lifting of operations;
  3729 
  3730 * HOL/record: added general record equality rule to simpset; fixed
  3731 select-update simplification procedure to handle extended records as
  3732 well; admit "r" as field name;
  3733 
  3734 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3735 other numeric types and also as the identity of groups, rings, etc.;
  3736 
  3737 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3738 Types nat and int belong to this axclass;
  3739 
  3740 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3741    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3742    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3743   two terms #m*u and #n*u are replaced by #(m+n)*u
  3744     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3745   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3746     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3747 
  3748 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3749 powerful prover for predicate logic but knows nothing of clasets; see
  3750 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3751 
  3752 * HOL: new version of "case_tac" subsumes both boolean case split and
  3753 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3754 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3755 
  3756 * HOL: simplification no longer dives into case-expressions: only the
  3757 selector expression is simplified, but not the remaining arms; to
  3758 enable full simplification of case-expressions for datatype t, you may
  3759 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3760 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3761 
  3762 * HOL/recdef: the recursion equations generated by 'recdef' for
  3763 function 'f' are now called f.simps instead of f.rules; if all
  3764 termination conditions are proved automatically, these simplification
  3765 rules are added to the simpset, as in primrec; rules may be named
  3766 individually as well, resulting in a separate list of theorems for
  3767 each equation;
  3768 
  3769 * HOL/While is a new theory that provides a while-combinator. It
  3770 permits the definition of tail-recursive functions without the
  3771 provision of a termination measure. The latter is necessary once the
  3772 invariant proof rule for while is applied.
  3773 
  3774 * HOL: new (overloaded) notation for the set of elements below/above
  3775 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3776 
  3777 * HOL: theorems impI, allI, ballI bound as "strip";
  3778 
  3779 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3780 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3781 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3782 
  3783 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3784 
  3785 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3786 main HOL, but was unused);
  3787 
  3788 * HOL: fewer consts declared as global (e.g. have to refer to
  3789 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3790 
  3791 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3792 in case of overlap with user translations (e.g. judgements over
  3793 tuples); (note that the underlying logical represenation is still
  3794 bogus);
  3795 
  3796 
  3797 *** ZF ***
  3798 
  3799 * ZF: simplification automatically cancels common terms in arithmetic
  3800 expressions over nat and int;
  3801 
  3802 * ZF: new treatment of nat to minimize type-checking: all operators
  3803 coerce their operands to a natural number using the function natify,
  3804 making the algebraic laws unconditional;
  3805 
  3806 * ZF: as above, for int: operators coerce their operands to an integer
  3807 using the function intify;
  3808 
  3809 * ZF: the integer library now contains many of the usual laws for the
  3810 orderings, including $<=, and monotonicity laws for $+ and $*;
  3811 
  3812 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3813 simplification;
  3814 
  3815 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3816 to the simplifier and classical reasoner simultaneously;
  3817 
  3818 
  3819 *** General ***
  3820 
  3821 * Provers: blast_tac now handles actual object-logic rules as
  3822 assumptions; note that auto_tac uses blast_tac internally as well;
  3823 
  3824 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3825 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3826 
  3827 * Provers: delrules now handles destruct rules as well (no longer need
  3828 explicit make_elim);
  3829 
  3830 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3831   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3832 use instead the strong form,
  3833   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3834 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3835 from destruct-rules;
  3836 
  3837 * Provers: Simplifier.easy_setup provides a fast path to basic
  3838 Simplifier setup for new object-logics;
  3839 
  3840 * Pure: AST translation rules no longer require constant head on LHS;
  3841 
  3842 * Pure: improved name spaces: ambiguous output is qualified; support
  3843 for hiding of names;
  3844 
  3845 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3846 XSYMBOL_HOME; no longer need to do manual configuration in most
  3847 situations;
  3848 
  3849 * system: compression of ML heaps images may now be controlled via -c
  3850 option of isabelle and isatool usedir (currently only observed by
  3851 Poly/ML);
  3852 
  3853 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3854 useful for remote X11);
  3855 
  3856 * system: provide TAGS file for Isabelle sources;
  3857 
  3858 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3859 order;
  3860 
  3861 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3862 timing flag supersedes proof_timing and Toplevel.trace;
  3863 
  3864 * ML: new combinators |>> and |>>> for incremental transformations
  3865 with secondary results (e.g. certain theory extensions):
  3866 
  3867 * ML: PureThy.add_defs gets additional argument to indicate potential
  3868 overloading (usually false);
  3869 
  3870 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3871 results;
  3872 
  3873 
  3874 
  3875 New in Isabelle99 (October 1999)
  3876 --------------------------------
  3877 
  3878 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3879 
  3880 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3881 are no longer simplified.  (This allows the simplifier to unfold recursive
  3882 functional programs.)  To restore the old behaviour, declare
  3883 
  3884     Delcongs [if_weak_cong];
  3885 
  3886 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3887 complement;
  3888 
  3889 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3890 
  3891 * HOL/datatype: mutual_induct_tac no longer exists --
  3892   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3893 
  3894 * HOL/typedef: fixed type inference for representing set; type
  3895 arguments now have to occur explicitly on the rhs as type constraints;
  3896 
  3897 * ZF: The con_defs part of an inductive definition may no longer refer
  3898 to constants declared in the same theory;
  3899 
  3900 * HOL, ZF: the function mk_cases, generated by the inductive
  3901 definition package, has lost an argument.  To simplify its result, it
  3902 uses the default simpset instead of a supplied list of theorems.
  3903 
  3904 * HOL/List: the constructors of type list are now Nil and Cons;
  3905 
  3906 * Simplifier: the type of the infix ML functions
  3907         setSSolver addSSolver setSolver addSolver
  3908 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3909 for packaging solvers. A solver is created via
  3910         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3911 where the string argument is only a comment.
  3912 
  3913 
  3914 *** Proof tools ***
  3915 
  3916 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3917 decision procedure for linear arithmetic. Currently it is used for
  3918 types `nat', `int', and `real' in HOL (see below); it can, should and
  3919 will be instantiated for other types and logics as well.
  3920 
  3921 * The simplifier now accepts rewrite rules with flexible heads, eg
  3922      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3923   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3924   matching.
  3925 
  3926 
  3927 *** General ***
  3928 
  3929 * New Isabelle/Isar subsystem provides an alternative to traditional
  3930 tactical theorem proving; together with the ProofGeneral/isar user
  3931 interface it offers an interactive environment for developing human
  3932 readable proof documents (Isar == Intelligible semi-automated
  3933 reasoning); for further information see isatool doc isar-ref,
  3934 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3935 
  3936 * improved and simplified presentation of theories: better HTML markup
  3937 (including colors), graph views in several sizes; isatool usedir now
  3938 provides a proper interface for user theories (via -P option); actual
  3939 document preparation based on (PDF)LaTeX is available as well (for
  3940 new-style theories only); see isatool doc system for more information;
  3941 
  3942 * native support for Proof General, both for classic Isabelle and
  3943 Isabelle/Isar;
  3944 
  3945 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3946 using the graph browser tool;
  3947 
  3948 * Isabelle manuals now also available as PDF;
  3949 
  3950 * theory loader rewritten from scratch (may not be fully
  3951 bug-compatible); old loadpath variable has been replaced by show_path,
  3952 add_path, del_path, reset_path functions; new operations such as
  3953 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3954 isatool doc ref);
  3955 
  3956 * improved isatool install: option -k creates KDE application icon,
  3957 option -p DIR installs standalone binaries;
  3958 
  3959 * added ML_PLATFORM setting (useful for cross-platform installations);
  3960 more robust handling of platform specific ML images for SML/NJ;
  3961 
  3962 * the settings environment is now statically scoped, i.e. it is never
  3963 created again in sub-processes invoked from isabelle, isatool, or
  3964 Isabelle;
  3965 
  3966 * path element specification '~~' refers to '$ISABELLE_HOME';
  3967 
  3968 * in locales, the "assumes" and "defines" parts may be omitted if
  3969 empty;
  3970 
  3971 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3972 long arrows);
  3973 
  3974 * new print_mode "HTML";
  3975 
  3976 * new flag show_tags controls display of tags of theorems (which are
  3977 basically just comments that may be attached by some tools);
  3978 
  3979 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3980 mode and goal output format:
  3981 
  3982 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3983 244c244
  3984 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3985 ---
  3986 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3987 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3988 181c181
  3989 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3990 ---
  3991 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3992 
  3993 * function bind_thms stores lists of theorems (cf. bind_thm);
  3994 
  3995 * new shorthand tactics ftac, eatac, datac, fatac;
  3996 
  3997 * qed (and friends) now accept "" as result name; in that case the
  3998 theorem is not stored, but proper checks and presentation of the
  3999 result still apply;
  4000 
  4001 * theorem database now also indexes constants "Trueprop", "all",
  4002 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4003 
  4004 
  4005 *** HOL ***
  4006 
  4007 ** HOL arithmetic **
  4008 
  4009 * There are now decision procedures for linear arithmetic over nat and
  4010 int:
  4011 
  4012 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4013 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4014 are treated as atomic; subformulae not involving type `nat' or `int'
  4015 are ignored; quantified subformulae are ignored unless they are
  4016 positive universal or negative existential. The tactic has to be
  4017 invoked by hand and can be a little bit slow. In particular, the
  4018 running time is exponential in the number of occurrences of `min' and
  4019 `max', and `-' on `nat'.
  4020 
  4021 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4022 (negated) (in)equalities among the premises and the conclusion into
  4023 account (i.e. no compound formulae) and does not know about `min' and
  4024 `max', and `-' on `nat'. It is fast and is used automatically by the
  4025 simplifier.
  4026 
  4027 NB: At the moment, these decision procedures do not cope with mixed
  4028 nat/int formulae where the two parts interact, such as `m < n ==>
  4029 int(m) < int(n)'.
  4030 
  4031 * HOL/Numeral provides a generic theory of numerals (encoded
  4032 efficiently as bit strings); setup for types nat/int/real is in place;
  4033 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4034 int, existing theories and proof scripts may require a few additional
  4035 type constraints;
  4036 
  4037 * integer division and remainder can now be performed on constant
  4038 arguments;
  4039 
  4040 * many properties of integer multiplication, division and remainder
  4041 are now available;
  4042 
  4043 * An interface to the Stanford Validity Checker (SVC) is available through the
  4044 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4045 are proved automatically.  SVC must be installed separately, and its results
  4046 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4047 invocation of the underlying oracle).  For SVC see
  4048   http://verify.stanford.edu/SVC
  4049 
  4050 * IsaMakefile: the HOL-Real target now builds an actual image;
  4051 
  4052 
  4053 ** HOL misc **
  4054 
  4055 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4056 (in Isabelle/Isar) -- by Gertrud Bauer;
  4057 
  4058 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4059 analysis for assembly languages with subtypes;
  4060 
  4061 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4062 -- avoids syntactic ambiguities and treats state, transition, and
  4063 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4064 changed syntax and (many) tactics;
  4065 
  4066 * HOL/inductive: Now also handles more general introduction rules such
  4067   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4068   theorems are now maintained within the theory (maintained via the
  4069   "mono" attribute);
  4070 
  4071 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4072   (using function types) such as
  4073 
  4074   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4075 
  4076 * HOL/record: record_simproc (part of the default simpset) takes care
  4077 of selectors applied to updated records; record_split_tac is no longer
  4078 part of the default claset; update_defs may now be removed from the
  4079 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4080 
  4081   claset_ref () := claset() addSWrapper record_split_wrapper;
  4082   Delsimprocs [record_simproc]
  4083 
  4084 * HOL/typedef: fixed type inference for representing set; type
  4085 arguments now have to occur explicitly on the rhs as type constraints;
  4086 
  4087 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4088 names rather than an ML expression;
  4089 
  4090 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4091 supplied later.  Program schemes can be defined, such as
  4092     "While B C s = (if B s then While B C (C s) else s)"
  4093 where the well-founded relation can be chosen after B and C have been given.
  4094 
  4095 * HOL/List: the constructors of type list are now Nil and Cons;
  4096 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4097 course, ML tools referring to List.list.op # etc. have to be adapted;
  4098 
  4099 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4100 disabled by default; run isabelle with option -m HOL to get back to
  4101 the original Gordon/HOL-style output;
  4102 
  4103 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4104 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4105 
  4106 * HOL basic syntax simplified (more orthogonal): all variants of
  4107 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4108 Eps operator is provided as well: "SOME x. P[x]";
  4109 
  4110 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4111 
  4112 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4113 thus available for user theories;
  4114 
  4115 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4116 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4117 time;
  4118 
  4119 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4120 several times and then mp;
  4121 
  4122 
  4123 *** LK ***
  4124 
  4125 * the notation <<...>> is now available as a notation for sequences of
  4126 formulas;
  4127 
  4128 * the simplifier is now installed
  4129 
  4130 * the axiom system has been generalized (thanks to Soren Heilmann)
  4131 
  4132 * the classical reasoner now has a default rule database
  4133 
  4134 
  4135 *** ZF ***
  4136 
  4137 * new primrec section allows primitive recursive functions to be given
  4138 directly (as in HOL) over datatypes and the natural numbers;
  4139 
  4140 * new tactics induct_tac and exhaust_tac for induction (or case
  4141 analysis) over datatypes and the natural numbers;
  4142 
  4143 * the datatype declaration of type T now defines the recursor T_rec;
  4144 
  4145 * simplification automatically does freeness reasoning for datatype
  4146 constructors;
  4147 
  4148 * automatic type-inference, with AddTCs command to insert new
  4149 type-checking rules;
  4150 
  4151 * datatype introduction rules are now added as Safe Introduction rules
  4152 to the claset;
  4153 
  4154 * the syntax "if P then x else y" is now available in addition to
  4155 if(P,x,y);
  4156 
  4157 
  4158 *** Internal programming interfaces ***
  4159 
  4160 * tuned simplifier trace output; new flag debug_simp;
  4161 
  4162 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4163 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4164 
  4165 * AxClass.axclass_tac lost the theory argument;
  4166 
  4167 * tuned current_goals_markers semantics: begin / end goal avoids
  4168 printing empty lines;
  4169 
  4170 * removed prs and prs_fn hook, which was broken because it did not
  4171 include \n in its semantics, forcing writeln to add one
  4172 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4173 string -> unit if you really want to output text without newline;
  4174 
  4175 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4176 plain output, interface builders may have to enable 'isabelle_font'
  4177 mode to get Isabelle font glyphs as before;
  4178 
  4179 * refined token_translation interface; INCOMPATIBILITY: output length
  4180 now of type real instead of int;
  4181 
  4182 * theory loader actions may be traced via new ThyInfo.add_hook
  4183 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4184 your own database of information attached to *whole* theories -- as
  4185 opposed to intra-theory data slots offered via TheoryDataFun;
  4186 
  4187 * proper handling of dangling sort hypotheses (at last!);
  4188 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4189 extra sort hypotheses that can be witnessed from the type signature;
  4190 the force_strip_shyps flag is gone, any remaining shyps are simply
  4191 left in the theorem (with a warning issued by strip_shyps_warning);
  4192 
  4193 
  4194 
  4195 New in Isabelle98-1 (October 1998)
  4196 ----------------------------------
  4197 
  4198 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4199 
  4200 * several changes of automated proof tools;
  4201 
  4202 * HOL: major changes to the inductive and datatype packages, including
  4203 some minor incompatibilities of theory syntax;
  4204 
  4205 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4206 called `inj_on';
  4207 
  4208 * HOL: removed duplicate thms in Arith:
  4209   less_imp_add_less  should be replaced by  trans_less_add1
  4210   le_imp_add_le      should be replaced by  trans_le_add1
  4211 
  4212 * HOL: unary minus is now overloaded (new type constraints may be
  4213 required);
  4214 
  4215 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4216 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4217 now taken as an integer constant.
  4218 
  4219 * Pure: ML function 'theory_of' renamed to 'theory';
  4220 
  4221 
  4222 *** Proof tools ***
  4223 
  4224 * Simplifier:
  4225   1. Asm_full_simp_tac is now more aggressive.
  4226      1. It will sometimes reorient premises if that increases their power to
  4227         simplify.
  4228      2. It does no longer proceed strictly from left to right but may also
  4229         rotate premises to achieve further simplification.
  4230      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4231      old Asm_full_simp_tac in that it does not rotate premises.
  4232   2. The simplifier now knows a little bit about nat-arithmetic.
  4233 
  4234 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4235 allows for selected deletion of wrappers, by introduction of names for
  4236 wrapper functionals.  This implies that addbefore, addSbefore,
  4237 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4238 and that adding two tactics with the same name overwrites the first
  4239 one (emitting a warning).
  4240   type wrapper = (int -> tactic) -> (int -> tactic)
  4241   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4242   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4243   delWrapper, delSWrapper: claset *  string            -> claset
  4244   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4245 
  4246 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4247 semantics; addbefore now affects only the unsafe part of step_tac
  4248 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4249 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4250 by Force_tac;
  4251 
  4252 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4253 compWrapper; added safe wrapper (and access functions for it);
  4254 
  4255 * HOL/split_all_tac is now much faster and fails if there is nothing
  4256 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4257 and the names of the automatically generated variables have changed.
  4258 split_all_tac has moved within claset() from unsafe wrappers to safe
  4259 wrappers, which means that !!-bound variables are split much more
  4260 aggressively, and safe_tac and clarify_tac now split such variables.
  4261 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4262 Note: the same holds for record_split_tac, which does the job of
  4263 split_all_tac for record fields.
  4264 
  4265 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4266 permanently to the default simpset using Addsplits just like
  4267 Addsimps. They can be removed via Delsplits just like
  4268 Delsimps. Lower-case versions are also available.
  4269 
  4270 * HOL/Simplifier: The rule split_if is now part of the default
  4271 simpset. This means that the simplifier will eliminate all occurrences
  4272 of if-then-else in the conclusion of a goal. To prevent this, you can
  4273 either remove split_if completely from the default simpset by
  4274 `Delsplits [split_if]' or remove it in a specific call of the
  4275 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4276 other case splitting rules to/from the default simpset: every datatype
  4277 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4278 t is the name of the datatype).
  4279 
  4280 * Classical reasoner / Simplifier combination: new force_tac (and
  4281 derivatives Force_tac, force) combines rewriting and classical
  4282 reasoning (and whatever other tools) similarly to auto_tac, but is
  4283 aimed to solve the given subgoal completely.
  4284 
  4285 
  4286 *** General ***
  4287 
  4288 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4289 and `goalw': the theory is no longer needed as an explicit argument -
  4290 the current theory context is used; assumptions are no longer returned
  4291 at the ML-level unless one of them starts with ==> or !!; it is
  4292 recommended to convert to these new commands using isatool fixgoal
  4293 (backup your sources first!);
  4294 
  4295 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4296 the current theory context, and 'theory' to lookup stored theories;
  4297 
  4298 * new theory section 'locale' for declaring constants, assumptions and
  4299 definitions that have local scope;
  4300 
  4301 * new theory section 'nonterminals' for purely syntactic types;
  4302 
  4303 * new theory section 'setup' for generic ML setup functions
  4304 (e.g. package initialization);
  4305 
  4306 * the distribution now includes Isabelle icons: see
  4307 lib/logo/isabelle-{small,tiny}.xpm;
  4308 
  4309 * isatool install - install binaries with absolute references to
  4310 ISABELLE_HOME/bin;
  4311 
  4312 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4313 
  4314 * print mode 'emacs' reserved for Isamode;
  4315 
  4316 * support multiple print (ast) translations per constant name;
  4317 
  4318 * theorems involving oracles are now printed with a suffixed [!];
  4319 
  4320 
  4321 *** HOL ***
  4322 
  4323 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4324 
  4325 * HOL/inductive package reorganized and improved: now supports mutual
  4326 definitions such as
  4327 
  4328   inductive EVEN ODD
  4329     intrs
  4330       null "0 : EVEN"
  4331       oddI "n : EVEN ==> Suc n : ODD"
  4332       evenI "n : ODD ==> Suc n : EVEN"
  4333 
  4334 new theorem list "elims" contains an elimination rule for each of the
  4335 recursive sets; inductive definitions now handle disjunctive premises
  4336 correctly (also ZF);
  4337 
  4338 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4339 "mutual_induct" no longer exists - the induction rule is always
  4340 contained in "induct";
  4341 
  4342 
  4343 * HOL/datatype package re-implemented and greatly improved: now
  4344 supports mutually recursive datatypes such as
  4345 
  4346   datatype
  4347     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4348             | SUM ('a aexp) ('a aexp)
  4349             | DIFF ('a aexp) ('a aexp)
  4350             | NUM 'a
  4351   and
  4352     'a bexp = LESS ('a aexp) ('a aexp)
  4353             | AND ('a bexp) ('a bexp)
  4354             | OR ('a bexp) ('a bexp)
  4355 
  4356 as well as indirectly recursive datatypes such as
  4357 
  4358   datatype
  4359     ('a, 'b) term = Var 'a
  4360                   | App 'b ((('a, 'b) term) list)
  4361 
  4362 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4363 induction on mutually / indirectly recursive datatypes.
  4364 
  4365 Primrec equations are now stored in theory and can be accessed via
  4366 <function_name>.simps.
  4367 
  4368 INCOMPATIBILITIES:
  4369 
  4370   - Theories using datatypes must now have theory Datatype as an
  4371     ancestor.
  4372   - The specific <typename>.induct_tac no longer exists - use the
  4373     generic induct_tac instead.
  4374   - natE has been renamed to nat.exhaust - use exhaust_tac
  4375     instead of res_inst_tac ... natE. Note that the variable
  4376     names in nat.exhaust differ from the names in natE, this
  4377     may cause some "fragile" proofs to fail.
  4378   - The theorems split_<typename>_case and split_<typename>_case_asm
  4379     have been renamed to <typename>.split and <typename>.split_asm.
  4380   - Since default sorts of type variables are now handled correctly,
  4381     some datatype definitions may have to be annotated with explicit
  4382     sort constraints.
  4383   - Primrec definitions no longer require function name and type
  4384     of recursive argument.
  4385 
  4386 Consider using isatool fixdatatype to adapt your theories and proof
  4387 scripts to the new package (backup your sources first!).
  4388 
  4389 
  4390 * HOL/record package: considerably improved implementation; now
  4391 includes concrete syntax for record types, terms, updates; theorems
  4392 for surjective pairing and splitting !!-bound record variables; proof
  4393 support is as follows:
  4394 
  4395   1) standard conversions (selectors or updates applied to record
  4396 constructor terms) are part of the standard simpset;
  4397 
  4398   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4399 made part of standard simpset and claset via addIffs;
  4400 
  4401   3) a tactic for record field splitting (record_split_tac) is part of
  4402 the standard claset (addSWrapper);
  4403 
  4404 To get a better idea about these rules you may retrieve them via
  4405 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4406 the name of your record type.
  4407 
  4408 The split tactic 3) conceptually simplifies by the following rule:
  4409 
  4410   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4411 
  4412 Thus any record variable that is bound by meta-all will automatically
  4413 blow up into some record constructor term, consequently the
  4414 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4415 solve record problems automatically.
  4416 
  4417 
  4418 * reorganized the main HOL image: HOL/Integ and String loaded by
  4419 default; theory Main includes everything;
  4420 
  4421 * automatic simplification of integer sums and comparisons, using cancellation;
  4422 
  4423 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4424 
  4425 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4426 
  4427 * many new identities for unions, intersections, set difference, etc.;
  4428 
  4429 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4430 called split_if, split_split, split_sum_case and split_nat_case (to go
  4431 with add/delsplits);
  4432 
  4433 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4434 (?x::unit) = (); this is made part of the default simpset, which COULD
  4435 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4436 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4437 unit_abs_eta_conv is added in order to counter the effect of
  4438 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4439 %u.f();
  4440 
  4441 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4442 makes more sense);
  4443 
  4444 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4445   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4446   disjointness reasoning but breaking a few old proofs.
  4447 
  4448 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4449 to 'converse' from 'inverse' (for compatibility with ZF and some
  4450 literature);
  4451 
  4452 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4453 the well-founded relation;
  4454 
  4455 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4456     Compl A.  The "Compl" syntax remains available as input syntax for this
  4457     release ONLY.
  4458 
  4459 * HOL/Update: new theory of function updates:
  4460     f(a:=b) == %x. if x=a then b else f x
  4461 may also be iterated as in f(a:=b,c:=d,...);
  4462 
  4463 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4464 
  4465 * HOL/List:
  4466   - new function list_update written xs[i:=v] that updates the i-th
  4467     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4468   - new function `upt' written [i..j(] which generates the list
  4469     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4470     bound write [i..j], which is a shorthand for [i..j+1(].
  4471   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4472 
  4473 * HOL/Arith:
  4474   - removed 'pred' (predecessor) function;
  4475   - generalized some theorems about n-1;
  4476   - many new laws about "div" and "mod";
  4477   - new laws about greatest common divisors (see theory ex/Primes);
  4478 
  4479 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4480 instead of "inverse";
  4481 
  4482 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4483   of the multiset ordering;
  4484 
  4485 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4486   (not included by default);
  4487 
  4488 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4489 
  4490 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4491   programs, i.e. different program variables may have different types.
  4492 
  4493 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4494   [previously, this check worked only if the rewrite rule was unconditional]
  4495   Now rew can involve either definitions or equalities (either == or =).
  4496 
  4497 
  4498 *** ZF ***
  4499 
  4500 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4501   only the theorems proved on ZF.ML;
  4502 
  4503 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4504   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4505   disjointness reasoning but breaking a few old proofs.
  4506 
  4507 * ZF/Update: new theory of function updates
  4508     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4509   may also be iterated as in f(a:=b,c:=d,...);
  4510 
  4511 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4512 
  4513 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4514   [previously, this check worked only if the rewrite rule was unconditional]
  4515   Now rew can involve either definitions or equalities (either == or =).
  4516 
  4517 * case_tac provided for compatibility with HOL
  4518     (like the old excluded_middle_tac, but with subgoals swapped)
  4519 
  4520 
  4521 *** Internal programming interfaces ***
  4522 
  4523 * Pure: several new basic modules made available for general use, see
  4524 also src/Pure/README;
  4525 
  4526 * improved the theory data mechanism to support encapsulation (data
  4527 kind name replaced by private Object.kind, acting as authorization
  4528 key); new type-safe user interface via functor TheoryDataFun; generic
  4529 print_data function becomes basically useless;
  4530 
  4531 * removed global_names compatibility flag -- all theory declarations
  4532 are qualified by default;
  4533 
  4534 * module Pure/Syntax now offers quote / antiquote translation
  4535 functions (useful for Hoare logic etc. with implicit dependencies);
  4536 see HOL/ex/Antiquote for an example use;
  4537 
  4538 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4539 cterm -> thm;
  4540 
  4541 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4542 subgoal;
  4543 
  4544 * Display.print_goals function moved to Locale.print_goals;
  4545 
  4546 * standard print function for goals supports current_goals_markers
  4547 variable for marking begin of proof, end of proof, start of goal; the
  4548 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4549 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4550 for example;
  4551 
  4552 
  4553 
  4554 New in Isabelle98 (January 1998)
  4555 --------------------------------
  4556 
  4557 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4558 
  4559 * changed lexical syntax of terms / types: dots made part of long
  4560 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4561 
  4562 * simpset (and claset) reference variable replaced by functions
  4563 simpset / simpset_ref;
  4564 
  4565 * no longer supports theory aliases (via merge) and non-trivial
  4566 implicit merge of thms' signatures;
  4567 
  4568 * most internal names of constants changed due to qualified names;
  4569 
  4570 * changed Pure/Sequence interface (see Pure/seq.ML);
  4571 
  4572 
  4573 *** General Changes ***
  4574 
  4575 * hierachically structured name spaces (for consts, types, axms, thms
  4576 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4577 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4578 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4579 long_names for fully qualified output names; NOTE: ML programs
  4580 (special tactics, packages etc.) referring to internal names may have
  4581 to be adapted to cope with fully qualified names; in case of severe
  4582 backward campatibility problems try setting 'global_names' at compile
  4583 time to have enrything declared within a flat name space; one may also
  4584 fine tune name declarations in theories via the 'global' and 'local'
  4585 section;
  4586 
  4587 * reimplemented the implicit simpset and claset using the new anytype
  4588 data filed in signatures; references simpset:simpset ref etc. are
  4589 replaced by functions simpset:unit->simpset and
  4590 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4591 to patch your ML files accordingly;
  4592 
  4593 * HTML output now includes theory graph data for display with Java
  4594 applet or isatool browser; data generated automatically via isatool
  4595 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4596 
  4597 * defs may now be conditional; improved rewrite_goals_tac to handle
  4598 conditional equations;
  4599 
  4600 * defs now admits additional type arguments, using TYPE('a) syntax;
  4601 
  4602 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4603 creates a new theory node; implicit merge of thms' signatures is
  4604 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4605 transfer:theory->thm->thm in (rare) cases;
  4606 
  4607 * improved handling of draft signatures / theories; draft thms (and
  4608 ctyps, cterms) are automatically promoted to real ones;
  4609 
  4610 * slightly changed interfaces for oracles: admit many per theory, named
  4611 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4612 
  4613 * print_goals: optional output of const types (set show_consts and
  4614 show_types);
  4615 
  4616 * improved output of warnings (###) and errors (***);
  4617 
  4618 * subgoal_tac displays a warning if the new subgoal has type variables;
  4619 
  4620 * removed old README and Makefiles;
  4621 
  4622 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4623 
  4624 * removed obsolete init_pps and init_database;
  4625 
  4626 * deleted the obsolete tactical STATE, which was declared by
  4627     fun STATE tacfun st = tacfun st st;
  4628 
  4629 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4630 (which abbreviates $HOME);
  4631 
  4632 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4633 use isatool fixseq to adapt your ML programs (this works for fully
  4634 qualified references to the Sequence structure only!);
  4635 
  4636 * use_thy no longer requires writable current directory; it always
  4637 reloads .ML *and* .thy file, if either one is out of date;
  4638 
  4639 
  4640 *** Classical Reasoner ***
  4641 
  4642 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4643 tactics that use classical reasoning to simplify a subgoal without
  4644 splitting it into several subgoals;
  4645 
  4646 * Safe_tac: like safe_tac but uses the default claset;
  4647 
  4648 
  4649 *** Simplifier ***
  4650 
  4651 * added simplification meta rules:
  4652     (asm_)(full_)simplify: simpset -> thm -> thm;
  4653 
  4654 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4655 logics (again);
  4656 
  4657 * added prems argument to simplification procedures;
  4658 
  4659 * HOL, FOL, ZF: added infix function `addsplits':
  4660   instead of `<simpset> setloop (split_tac <thms>)'
  4661   you can simply write `<simpset> addsplits <thms>'
  4662 
  4663 
  4664 *** Syntax ***
  4665 
  4666 * TYPE('a) syntax for type reflection terms;
  4667 
  4668 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4669 
  4670 * pretty printer: changed order of mixfix annotation preference (again!);
  4671 
  4672 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4673 
  4674 
  4675 *** HOL ***
  4676 
  4677 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4678   with `addloop' of the simplifier to faciliate case splitting in premises.
  4679 
  4680 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4681 
  4682 * HOL/Auth: new protocol proofs including some for the Internet
  4683   protocol TLS;
  4684 
  4685 * HOL/Map: new theory of `maps' a la VDM;
  4686 
  4687 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4688 cancelling out common nat summands from =, <, <= (in)equalities, or
  4689 differences; simplification procedures nat_cancel_factor for
  4690 cancelling common factor from =, <, <= (in)equalities over natural
  4691 sums; nat_cancel contains both kinds of procedures, it is installed by
  4692 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4693 
  4694 * HOL/simplifier: terms of the form
  4695   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4696   are rewritten to
  4697   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4698   and those of the form
  4699   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4700   are rewritten to
  4701   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4702 
  4703 * HOL/datatype
  4704   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4705 
  4706   P(t_case f1 ... fn x) =
  4707      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4708         ...
  4709        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4710      )
  4711 
  4712   and a theorem `split_t_case_asm' of the form
  4713 
  4714   P(t_case f1 ... fn x) =
  4715     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4716         ...
  4717        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4718      )
  4719   which can be added to a simpset via `addsplits'. The existing theorems
  4720   expand_list_case and expand_option_case have been renamed to
  4721   split_list_case and split_option_case.
  4722 
  4723 * HOL/Arithmetic:
  4724   - `pred n' is automatically converted to `n-1'.
  4725     Users are strongly encouraged not to use `pred' any longer,
  4726     because it will disappear altogether at some point.
  4727   - Users are strongly encouraged to write "0 < n" rather than
  4728     "n ~= 0". Theorems and proof tools have been modified towards this
  4729     `standard'.
  4730 
  4731 * HOL/Lists:
  4732   the function "set_of_list" has been renamed "set" (and its theorems too);
  4733   the function "nth" now takes its arguments in the reverse order and
  4734   has acquired the infix notation "!" as in "xs!n".
  4735 
  4736 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4737 
  4738 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4739   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4740 
  4741 * HOL/record: extensible records with schematic structural subtyping
  4742 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4743 still lacks various theorems and concrete record syntax;
  4744 
  4745 
  4746 *** HOLCF ***
  4747 
  4748 * removed "axioms" and "generated by" sections;
  4749 
  4750 * replaced "ops" section by extended "consts" section, which is capable of
  4751   handling the continuous function space "->" directly;
  4752 
  4753 * domain package:
  4754   . proves theorems immediately and stores them in the theory,
  4755   . creates hierachical name space,
  4756   . now uses normal mixfix annotations (instead of cinfix...),
  4757   . minor changes to some names and values (for consistency),
  4758   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4759   . separator between mutual domain defs: changed "," to "and",
  4760   . improved handling of sort constraints;  now they have to
  4761     appear on the left-hand side of the equations only;
  4762 
  4763 * fixed LAM <x,y,zs>.b syntax;
  4764 
  4765 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4766 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4767 
  4768 
  4769 *** FOL and ZF ***
  4770 
  4771 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4772   with `addloop' of the simplifier to faciliate case splitting in premises.
  4773 
  4774 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4775 in HOL, they strip ALL and --> from proved theorems;
  4776 
  4777 
  4778 
  4779 New in Isabelle94-8 (May 1997)
  4780 ------------------------------
  4781 
  4782 *** General Changes ***
  4783 
  4784 * new utilities to build / run / maintain Isabelle etc. (in parts
  4785 still somewhat experimental); old Makefiles etc. still functional;
  4786 
  4787 * new 'Isabelle System Manual';
  4788 
  4789 * INSTALL text, together with ./configure and ./build scripts;
  4790 
  4791 * reimplemented type inference for greater efficiency, better error
  4792 messages and clean internal interface;
  4793 
  4794 * prlim command for dealing with lots of subgoals (an easier way of
  4795 setting goals_limit);
  4796 
  4797 
  4798 *** Syntax ***
  4799 
  4800 * supports alternative (named) syntax tables (parser and pretty
  4801 printer); internal interface is provided by add_modesyntax(_i);
  4802 
  4803 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4804 be used in conjunction with the Isabelle symbol font; uses the
  4805 "symbols" syntax table;
  4806 
  4807 * added token_translation interface (may translate name tokens in
  4808 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4809 the current print_mode); IMPORTANT: user print translation functions
  4810 are responsible for marking newly introduced bounds
  4811 (Syntax.mark_boundT);
  4812 
  4813 * token translations for modes "xterm" and "xterm_color" that display
  4814 names in bold, underline etc. or colors (which requires a color
  4815 version of xterm);
  4816 
  4817 * infixes may now be declared with names independent of their syntax;
  4818 
  4819 * added typed_print_translation (like print_translation, but may
  4820 access type of constant);
  4821 
  4822 
  4823 *** Classical Reasoner ***
  4824 
  4825 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4826 some limitations.  Blast_tac...
  4827   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4828   + ignores elimination rules that don't have the correct format
  4829         (the conclusion MUST be a formula variable)
  4830   + ignores types, which can make HOL proofs fail
  4831   + rules must not require higher-order unification, e.g. apply_type in ZF
  4832     [message "Function Var's argument not a bound variable" relates to this]
  4833   + its proof strategy is more general but can actually be slower
  4834 
  4835 * substitution with equality assumptions no longer permutes other
  4836 assumptions;
  4837 
  4838 * minor changes in semantics of addafter (now called addaltern); renamed
  4839 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4840 (and access functions for it);
  4841 
  4842 * improved combination of classical reasoner and simplifier:
  4843   + functions for handling clasimpsets
  4844   + improvement of addss: now the simplifier is called _after_ the
  4845     safe steps.
  4846   + safe variant of addss called addSss: uses safe simplifications
  4847     _during_ the safe steps. It is more complete as it allows multiple
  4848     instantiations of unknowns (e.g. with slow_tac).
  4849 
  4850 *** Simplifier ***
  4851 
  4852 * added interface for simplification procedures (functions that
  4853 produce *proven* rewrite rules on the fly, depending on current
  4854 redex);
  4855 
  4856 * ordering on terms as parameter (used for ordered rewriting);
  4857 
  4858 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4859 
  4860 * the solver is now split into a safe and an unsafe part.
  4861 This should be invisible for the normal user, except that the
  4862 functions setsolver and addsolver have been renamed to setSolver and
  4863 addSolver; added safe_asm_full_simp_tac;
  4864 
  4865 
  4866 *** HOL ***
  4867 
  4868 * a generic induction tactic `induct_tac' which works for all datatypes and
  4869 also for type `nat';
  4870 
  4871 * a generic case distinction tactic `exhaust_tac' which works for all
  4872 datatypes and also for type `nat';
  4873 
  4874 * each datatype comes with a function `size';
  4875 
  4876 * patterns in case expressions allow tuple patterns as arguments to
  4877 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4878 
  4879 * primrec now also works with type nat;
  4880 
  4881 * recdef: a new declaration form, allows general recursive functions to be
  4882 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4883 
  4884 * the constant for negation has been renamed from "not" to "Not" to
  4885 harmonize with FOL, ZF, LK, etc.;
  4886 
  4887 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4888 infinite lists;
  4889 
  4890 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4891 
  4892 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4893 problems in commutative rings, using axiomatic type classes for + and *;
  4894 
  4895 * more examples in HOL/MiniML and HOL/Auth;
  4896 
  4897 * more default rewrite rules for quantifiers, union/intersection;
  4898 
  4899 * a new constant `arbitrary == @x.False';
  4900 
  4901 * HOLCF/IOA replaces old HOL/IOA;
  4902 
  4903 * HOLCF changes: derived all rules and arities
  4904   + axiomatic type classes instead of classes
  4905   + typedef instead of faking type definitions
  4906   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4907   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4908   + eliminated the types void, one, tr
  4909   + use unit lift and bool lift (with translations) instead of one and tr
  4910   + eliminated blift from Lift3.thy (use Def instead of blift)
  4911   all eliminated rules are derived as theorems --> no visible changes ;
  4912 
  4913 
  4914 *** ZF ***
  4915 
  4916 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4917 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4918 as ZF_cs addSIs [equalityI];
  4919 
  4920 
  4921 
  4922 New in Isabelle94-7 (November 96)
  4923 ---------------------------------
  4924 
  4925 * allowing negative levels (as offsets) in prlev and choplev;
  4926 
  4927 * super-linear speedup for large simplifications;
  4928 
  4929 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4930 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4931 FAIL); can suppress it using the command Delsimps (ex_simps @
  4932 all_simps); De Morgan laws are also now included, by default;
  4933 
  4934 * improved printing of ==>  :  ~:
  4935 
  4936 * new object-logic "Sequents" adds linear logic, while replacing LK
  4937 and Modal (thanks to Sara Kalvala);
  4938 
  4939 * HOL/Auth: correctness proofs for authentication protocols;
  4940 
  4941 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4942 examples on HOL/Auth);
  4943 
  4944 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4945 the rewriter and classical reasoner simultaneously;
  4946 
  4947 * function uresult no longer returns theorems in "standard" format;
  4948 regain previous version by: val uresult = standard o uresult;
  4949 
  4950 
  4951 
  4952 New in Isabelle94-6
  4953 -------------------
  4954 
  4955 * oracles -- these establish an interface between Isabelle and trusted
  4956 external reasoners, which may deliver results as theorems;
  4957 
  4958 * proof objects (in particular record all uses of oracles);
  4959 
  4960 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4961 
  4962 * "constdefs" section in theory files;
  4963 
  4964 * "primrec" section (HOL) no longer requires names;
  4965 
  4966 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4967 
  4968 
  4969 
  4970 New in Isabelle94-5
  4971 -------------------
  4972 
  4973 * reduced space requirements;
  4974 
  4975 * automatic HTML generation from theories;
  4976 
  4977 * theory files no longer require "..." (quotes) around most types;
  4978 
  4979 * new examples, including two proofs of the Church-Rosser theorem;
  4980 
  4981 * non-curried (1994) version of HOL is no longer distributed;
  4982 
  4983 
  4984 
  4985 New in Isabelle94-4
  4986 -------------------
  4987 
  4988 * greatly reduced space requirements;
  4989 
  4990 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4991 
  4992 * searchable theorem database (see the section "Retrieving theorems" on
  4993 page 8 of the Reference Manual);
  4994 
  4995 * new examples, including Grabczewski's monumental case study of the
  4996 Axiom of Choice;
  4997 
  4998 * The previous version of HOL renamed to Old_HOL;
  4999 
  5000 * The new version of HOL (previously called CHOL) uses a curried syntax
  5001 for functions.  Application looks like f a b instead of f(a,b);
  5002 
  5003 * Mutually recursive inductive definitions finally work in HOL;
  5004 
  5005 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5006 translates to the operator "split";
  5007 
  5008 
  5009 
  5010 New in Isabelle94-3
  5011 -------------------
  5012 
  5013 * new infix operator, addss, allowing the classical reasoner to
  5014 perform simplification at each step of its search.  Example:
  5015         fast_tac (cs addss ss)
  5016 
  5017 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5018 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5019 look like (a,b) instead of <a,b>;
  5020 
  5021 * PLEASE NOTE: CHOL will eventually replace HOL!
  5022 
  5023 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5024 It translates to the operator "split".  A new theory of integers is available;
  5025 
  5026 * In ZF, integer numerals now denote two's-complement binary integers.
  5027 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5028 
  5029 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5030 of the Axiom of Choice;
  5031 
  5032 
  5033 
  5034 New in Isabelle94-2
  5035 -------------------
  5036 
  5037 * Significantly faster resolution;
  5038 
  5039 * the different sections in a .thy file can now be mixed and repeated
  5040 freely;
  5041 
  5042 * Database of theorems for FOL, HOL and ZF.  New
  5043 commands including qed, qed_goal and bind_thm store theorems in the database.
  5044 
  5045 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5046 a given theory (thms_of), or find out what theory a theorem was proved in
  5047 (theory_of_thm);
  5048 
  5049 * Bugs fixed in the inductive definition and datatype packages;
  5050 
  5051 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5052 and HOL_dup_cs obsolete;
  5053 
  5054 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5055 have been removed;
  5056 
  5057 * Simpler definition of function space in ZF;
  5058 
  5059 * new results about cardinal and ordinal arithmetic in ZF;
  5060 
  5061 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5062 types;
  5063 
  5064 :mode=text:wrap=hard:maxLineLen=72:
  5065 $Id$