NEWS
author haftmann
Tue Sep 19 15:31:32 2006 +0200 (2006-09-19)
changeset 20607 926a76a84e97
parent 20582 ebd0e03c6a9b
child 20620 8b26f58c5646
permissions -rw-r--r--
Operational Equality
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory syntax: the header format ``theory A = B + C:'' has been
    10 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    11 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    12 
    13 * Theory syntax: the old non-Isar theory file format has been
    14 discontinued altogether.  Note that ML proof scripts may still be used
    15 with Isar theories; migration is usually quite simple with the ML
    16 function use_legacy_bindings.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: some popular names (e.g. "class", "if") are now
    19 keywords.  INCOMPATIBILITY, use double quotes.
    20 
    21 * Legacy goal package: reduced interface to the bare minimum required
    22 to keep existing proof scripts running.  Most other user-level
    23 functions are now part of the OldGoals structure, which is *not* open
    24 by default (consider isatool expandshort before open OldGoals).
    25 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    26 these tend to cause confusion about the actual goal (!) context being
    27 used here, which is not necessarily the same as the_context().
    28 
    29 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    30 
    31 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    32 by default, which means that "prems" (and also "fixed variables") are
    33 suppressed from proof state output.  Note that the ProofGeneral
    34 settings mechanism allows to change and save options persistently, but
    35 older versions of Isabelle will fail to start up if a negative prems
    36 limit is imposed.
    37 
    38 
    39 *** Document preparation ***
    40 
    41 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    42 check the given source text as ML type/structure, printing verbatim.
    43 
    44 
    45 *** Pure ***
    46 
    47 * class_package.ML offers a combination of axclasses and locales to achieve
    48 Haskell-like type classes in Isabelle. See HOL/ex/Classpackage.thy for examples.
    49 
    50 * Yet another code generator framework allows to generate executable code
    51 for ML and Haskell (including "class"es). A short usage sketch:
    52 
    53     internal compilation:
    54         code_gen <list of constants (term syntax)> (SML -)
    55     writing SML code to a file:
    56         code_gen <list of constants (term syntax)> (SML <filename>)
    57     writing Haskell code to a bunch of files:
    58         code_gen <list of constants (term syntax)> (Haskell <filename>)
    59 
    60 Reasonable default setup of framework in HOL/Main.
    61 
    62 See HOL/ex/Code*.thy for examples.
    63 
    64 Theorem attributs for selecting and transforming function equations theorems:
    65 
    66     [code fun]:       select a theorem as function equation for a specific constant
    67     [code nofun]:     deselect a theorem as function equation for a specific constant
    68     [code inline]:    select an equation theorem for unfolding (inlining) in place
    69     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    70 
    71 User-defined serializations (target in {SML, Haskell}):
    72 
    73     code_const <and-list of constants (term syntax)>
    74       {(target) <and-list of const target syntax>}+
    75 
    76     code_type <and-list of type constructors>
    77       {(target) <and-list of type target syntax>}+
    78 
    79     code_instance <and-list of instances>
    80       {(target)}+
    81         where instance ::= <type constructor> :: <class>
    82 
    83     code_class <and_list of classes>
    84       {(target) <and-list of class target syntax>}+
    85         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
    86 
    87 For code_instance and code_class, target SML is silently ignored.
    88 
    89 See HOL theories and HOL/ex/Code*.thy for usage examples.
    90 
    91 * Command 'no_translations' removes translation rules from theory
    92 syntax.
    93 
    94 * Overloaded definitions are now actually checked for acyclic
    95 dependencies.  The overloading scheme is slightly more general than
    96 that of Haskell98, although Isabelle does not demand an exact
    97 correspondence to type class and instance declarations.
    98 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
    99 exotic versions of overloading -- at the discretion of the user!
   100 
   101 Polymorphic constants are represented via type arguments, i.e. the
   102 instantiation that matches an instance against the most general
   103 declaration given in the signature.  For example, with the declaration
   104 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   105 as c(nat).  Overloading is essentially simultaneous structural
   106 recursion over such type arguments.  Incomplete specification patterns
   107 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   108 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   109 Command 'print_theory' outputs the normalized system of recursive
   110 equations, see section "definitions".
   111 
   112 * Isar: improper proof element 'guess' is like 'obtain', but derives
   113 the obtained context from the course of reasoning!  For example:
   114 
   115   assume "EX x y. A x & B y"   -- "any previous fact"
   116   then guess x and y by clarify
   117 
   118 This technique is potentially adventurous, depending on the facts and
   119 proof tools being involved here.
   120 
   121 * Isar: known facts from the proof context may be specified as literal
   122 propositions, using ASCII back-quote syntax.  This works wherever
   123 named facts used to be allowed so far, in proof commands, proof
   124 methods, attributes etc.  Literal facts are retrieved from the context
   125 according to unification of type and term parameters.  For example,
   126 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   127 theorems in the current context, then these are valid literal facts:
   128 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   129 
   130 There is also a proof method "fact" which does the same composition
   131 for explicit goal states, e.g. the following proof texts coincide with
   132 certain special cases of literal facts:
   133 
   134   have "A" by fact                 ==  note `A`
   135   have "A ==> B" by fact           ==  note `A ==> B`
   136   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   137   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   138 
   139 * Isar: ":" (colon) is no longer a symbolic identifier character in
   140 outer syntax.  Thus symbolic identifiers may be used without
   141 additional white space in declarations like this: ``assume *: A''.
   142 
   143 * Isar: 'print_facts' prints all local facts of the current context,
   144 both named and unnamed ones.
   145 
   146 * Isar: 'def' now admits simultaneous definitions, e.g.:
   147 
   148   def x == "t" and y == "u"
   149 
   150 * Isar: added command 'unfolding', which is structurally similar to
   151 'using', but affects both the goal state and facts by unfolding given
   152 rewrite rules.  Thus many occurrences of the 'unfold' method or
   153 'unfolded' attribute may be replaced by first-class proof text.
   154 
   155 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   156 and command 'unfolding' now all support object-level equalities
   157 (potentially conditional).  The underlying notion of rewrite rule is
   158 analogous to the 'rule_format' attribute, but *not* that of the
   159 Simplifier (which is usually more generous).
   160 
   161 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   162 method expression within a sandbox consisting of the first N
   163 sub-goals, which need to exist.  For example, ``simp_all [3]''
   164 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   165 simplifies all new goals that emerge from applying rule foo to the
   166 originally first one.
   167 
   168 * Isar: schematic goals are no longer restricted to higher-order
   169 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   170 expected.
   171 
   172 * Isar: the conclusion of a long theorem statement is now either
   173 'shows' (a simultaneous conjunction, as before), or 'obtains'
   174 (essentially a disjunction of cases with local parameters and
   175 assumptions).  The latter allows to express general elimination rules
   176 adequately; in this notation common elimination rules look like this:
   177 
   178   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   179     assumes "EX x. P x"
   180     obtains x where "P x"
   181 
   182   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   183     assumes "A & B"
   184     obtains A and B
   185 
   186   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   187     assumes "A | B"
   188     obtains
   189       A
   190     | B
   191 
   192 The subsequent classical rules even refer to the formal "thesis"
   193 explicitly:
   194 
   195   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   196     obtains "~ thesis"
   197 
   198   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   199     obtains "thesis ==> something"
   200 
   201 The actual proof of an 'obtains' statement is analogous to that of the
   202 Isar proof element 'obtain', only that there may be several cases.
   203 Optional case names may be specified in parentheses; these will be
   204 available both in the present proof and as annotations in the
   205 resulting rule, for later use with the 'cases' method (cf. attribute
   206 case_names).
   207 
   208 * Isar: 'print_statement' prints theorems from the current theory or
   209 proof context in long statement form, according to the syntax of a
   210 top-level lemma.
   211 
   212 * Isar: 'obtain' takes an optional case name for the local context
   213 introduction rule (default "that").
   214 
   215 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   216 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   217 to occur.
   218 
   219 * Pure: syntax "CONST name" produces a fully internalized constant
   220 according to the current context.  This is particularly useful for
   221 syntax translations that should refer to internal constant
   222 representations independently of name spaces.
   223 
   224 * Isar/locales: 'const_syntax' provides a robust interface to the
   225 'syntax' primitive that also works in a locale context.  Type
   226 declaration and internal syntactic representation of given constants
   227 retrieved from the context.
   228 
   229 * Isar/locales: new derived specification elements 'axiomatization',
   230 'definition', 'abbreviation', which support type-inference, admit
   231 object-level specifications (equality, equivalence).  See also the
   232 isar-ref manual.  Examples:
   233 
   234   axiomatization
   235     eq  (infix "===" 50)
   236     where eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   237 
   238   definition
   239     "f x y = x + y + 1"
   240     "g x = f x x"
   241 
   242   abbreviation
   243     neq  (infix "=!=" 50)
   244     "x =!= y == ~ (x === y)"
   245 
   246 These specifications may be also used in a locale context.  Then the
   247 constants being introduced depend on certain fixed parameters, and the
   248 constant name is qualified by the locale base name.  An internal
   249 abbreviation takes care for convenient input and output, making the
   250 parameters implicit and using the original short name.  See also
   251 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   252 entities from a monomorphic theory.
   253 
   254 Presently, abbreviations are only available 'in' a target locale, but
   255 not inherited by general import expressions.  Also note that
   256 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   257 'translations' in common applications.
   258 
   259 Concrete syntax is attached to specified constants in internal form,
   260 independently of name spaces.  The parse tree representation is
   261 slightly different -- use 'const_syntax' instead of raw 'syntax', and
   262 'translations' with explicit "CONST" markup to accommodate this.
   263 
   264 * Isar/locales: improved parameter handling:
   265 - use of locales "var" and "struct" no longer necessary;
   266 - parameter renamings are no longer required to be injective.
   267   This enables, for example, to define a locale for endomorphisms thus:
   268   locale endom = homom mult mult h.
   269 
   270 * Isar/locales: changed the way locales with predicates are defined.
   271 Instead of accumulating the specification, the imported expression is
   272 now an interpretation.
   273 INCOMPATIBILITY: different normal form of locale expressions.
   274 In particular, in interpretations of locales with predicates,
   275 goals repesenting already interpreted fragments are not removed
   276 automatically.  Use methods `intro_locales' and `unfold_locales'; see below.
   277 
   278 * Isar/locales: new methods `intro_locales' and `unfold_locales' provide
   279 backward reasoning on locales predicates.  The methods are aware of
   280 interpretations and discharge corresponding goals.  `intro_locales' is
   281 less aggressive then `unfold_locales' and does not unfold predicates to
   282 assumptions.
   283 
   284 * Isar/locales: the order in which locale fragments are accumulated
   285 has changed.  This enables to override declarations from fragments
   286 due to interpretations -- for example, unwanted simp rules.
   287 
   288 * Provers/induct: improved internal context management to support
   289 local fixes and defines on-the-fly.  Thus explicit meta-level
   290 connectives !! and ==> are rarely required anymore in inductive goals
   291 (using object-logic connectives for this purpose has been long
   292 obsolete anyway).  The subsequent proof patterns illustrate advanced
   293 techniques of natural induction; general datatypes and inductive sets
   294 work analogously (see also src/HOL/Lambda for realistic examples).
   295 
   296 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   297 parameters:
   298 
   299   lemma
   300     fixes n :: nat and x :: 'a
   301     assumes a: "A n x"
   302     shows "P n x"
   303     using a                     -- {* make induct insert fact a *}
   304   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   305     case 0
   306     show ?case sorry
   307   next
   308     case (Suc n)
   309     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   310     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   311     show ?case sorry
   312   qed
   313 
   314 (2) This is how to perform induction over ``expressions of a certain
   315 form'', using a locally defined inductive parameter n == "a x"
   316 together with strengthening (the latter is usually required to get
   317 sufficiently flexible induction hypotheses):
   318 
   319   lemma
   320     fixes a :: "'a => nat"
   321     assumes a: "A (a x)"
   322     shows "P (a x)"
   323     using a
   324   proof (induct n == "a x" arbitrary: x)
   325     ...
   326 
   327 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   328 particular technique.
   329 
   330 (3) This is how to perform existential reasoning ('obtains' or
   331 'obtain') by induction, while avoiding explicit object-logic
   332 encodings:
   333 
   334   lemma
   335     fixes n :: nat
   336     obtains x :: 'a where "P n x" and "Q n x"
   337   proof (induct n arbitrary: thesis)
   338     case 0
   339     obtain x where "P 0 x" and "Q 0 x" sorry
   340     then show thesis by (rule 0)
   341   next
   342     case (Suc n)
   343     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   344     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   345     then show thesis by (rule Suc.prems)
   346   qed
   347 
   348 Here the 'arbitrary: thesis' specification essentially modifies the
   349 scope of the formal thesis parameter, in order to the get the whole
   350 existence statement through the induction as expected.
   351 
   352 * Provers/induct: mutual induction rules are now specified as a list
   353 of rule sharing the same induction cases.  HOL packages usually
   354 provide foo_bar.inducts for mutually defined items foo and bar
   355 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   356 specify mutual induction rules differently, i.e. like this:
   357 
   358   (induct rule: foo_bar.inducts)
   359   (induct set: foo bar)
   360   (induct type: foo bar)
   361 
   362 The ML function ProjectRule.projections turns old-style rules into the
   363 new format.
   364 
   365 * Provers/induct: improved handling of simultaneous goals.  Instead of
   366 introducing object-level conjunction, the statement is now split into
   367 several conclusions, while the corresponding symbolic cases are
   368 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   369 explicitly.  For example:
   370 
   371   lemma
   372     fixes n :: nat
   373     shows "P n" and "Q n"
   374   proof (induct n)
   375     case 0 case 1
   376     show "P 0" sorry
   377   next
   378     case 0 case 2
   379     show "Q 0" sorry
   380   next
   381     case (Suc n) case 1
   382     note `P n` and `Q n`
   383     show "P (Suc n)" sorry
   384   next
   385     case (Suc n) case 2
   386     note `P n` and `Q n`
   387     show "Q (Suc n)" sorry
   388   qed
   389 
   390 The split into subcases may be deferred as follows -- this is
   391 particularly relevant for goal statements with local premises.
   392 
   393   lemma
   394     fixes n :: nat
   395     shows "A n ==> P n" and "B n ==> Q n"
   396   proof (induct n)
   397     case 0
   398     {
   399       case 1
   400       note `A 0`
   401       show "P 0" sorry
   402     next
   403       case 2
   404       note `B 0`
   405       show "Q 0" sorry
   406     }
   407   next
   408     case (Suc n)
   409     note `A n ==> P n` and `B n ==> Q n`
   410     {
   411       case 1
   412       note `A (Suc n)`
   413       show "P (Suc n)" sorry
   414     next
   415       case 2
   416       note `B (Suc n)`
   417       show "Q (Suc n)" sorry
   418     }
   419   qed
   420 
   421 If simultaneous goals are to be used with mutual rules, the statement
   422 needs to be structured carefully as a two-level conjunction, using
   423 lists of propositions separated by 'and':
   424 
   425   lemma
   426     shows "a : A ==> P1 a"
   427           "a : A ==> P2 a"
   428       and "b : B ==> Q1 b"
   429           "b : B ==> Q2 b"
   430           "b : B ==> Q3 b"
   431   proof (induct set: A B)
   432 
   433 * Provers/induct: support coinduction as well.  See
   434 src/HOL/Library/Coinductive_List.thy for various examples.
   435 
   436 * Simplifier: by default the simplifier trace only shows top level rewrites
   437 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   438 less danger of being flooded by the trace. The trace indicates where parts
   439 have been suppressed.
   440   
   441 * Provers/classical: removed obsolete classical version of elim_format
   442 attribute; classical elim/dest rules are now treated uniformly when
   443 manipulating the claset.
   444 
   445 * Provers/classical: stricter checks to ensure that supplied intro,
   446 dest and elim rules are well-formed; dest and elim rules must have at
   447 least one premise.
   448 
   449 * Provers/classical: attributes dest/elim/intro take an optional
   450 weight argument for the rule (just as the Pure versions).  Weights are
   451 ignored by automated tools, but determine the search order of single
   452 rule steps.
   453 
   454 * Syntax: input syntax now supports dummy variable binding "%_. b",
   455 where the body does not mention the bound variable.  Note that dummy
   456 patterns implicitly depend on their context of bounds, which makes
   457 "{_. _}" match any set comprehension as expected.  Potential
   458 INCOMPATIBILITY -- parse translations need to cope with syntactic
   459 constant "_idtdummy" in the binding position.
   460 
   461 * Syntax: removed obsolete syntactic constant "_K" and its associated
   462 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   463 for example "A -> B" => "Pi A (%_. B)".
   464 
   465 * Pure: 'class_deps' command visualizes the subclass relation, using
   466 the graph browser tool.
   467 
   468 
   469 *** HOL ***
   470 
   471 * New theory OperationalEquality providing class 'eq' with constant 'eq',
   472 allowing for code generation with polymorphic equality.
   473 
   474 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has been
   475 abandoned in favour of plain 'int'. INCOMPATIBILITY -- Significant changes
   476 for setting up numeral syntax for types:
   477 
   478   - new constants Numeral.pred and Numeral.succ instead
   479       of former Numeral.bin_pred and Numeral.bin_succ.
   480   - Use integer operations instead of bin_add, bin_mult and so on.
   481   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   482   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   483 
   484 See HOL/Integ/IntArith.thy for an example setup.
   485 
   486 * New top level command 'normal_form' computes the normal form of a term
   487 that may contain free variables. For example 'normal_form "rev[a,b,c]"'
   488 prints '[b,c,a]'. This command is suitable for heavy-duty computations
   489 because the functions are compiled to ML first.
   490 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as
   491 an identifier.
   492 
   493 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   494 25 like -->); output depends on the "iff" print_mode, the default is
   495 "A = B" (with priority 50).
   496 
   497 * Renamed constants in HOL.thy and Orderings.thy:
   498     op +   ~> HOL.plus
   499     op -   ~> HOL.minus
   500     uminus ~> HOL.uminus
   501     op *   ~> HOL.times
   502     op <   ~> Orderings.less
   503     op <=  ~> Orderings.less_eq
   504 
   505 Adaptions may be required in the following cases:
   506 
   507 a) User-defined constants using any of the names "plus", "minus", "times",
   508 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   509 may go wrong.
   510 INCOMPATIBILITY: use more specific names.
   511 
   512 b) Variables named "plus", "minus", "times", "less", "less_eq"
   513 INCOMPATIBILITY: use more specific names.
   514 
   515 c) Permutative equations (e.g. "a + b = b + a")
   516 Since the change of names also changes the order of terms, permutative
   517 rewrite rules may get applied in a different order. Experience shows that
   518 this is rarely the case (only two adaptions in the whole Isabelle
   519 distribution).
   520 INCOMPATIBILITY: rewrite proofs
   521 
   522 d) ML code directly refering to constant names
   523 This in general only affects hand-written proof tactics, simprocs and so on.
   524 INCOMPATIBILITY: grep your sourcecode and replace names.
   525 
   526 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   527 
   528 * The old set interval syntax "{m..n(}" (and relatives) has been removed.
   529   Use "{m..<n}" (and relatives) instead.
   530 
   531 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   532 "t = s" to False (by simproc "neq_simproc").  For backward
   533 compatibility this can be disabled by ML "reset use_neq_simproc".
   534 
   535 * "m dvd n" where m and n are numbers is evaluated to True/False by simp.
   536 
   537 * Theorem Cons_eq_map_conv no longer has attribute `simp'.
   538 
   539 * Theorem setsum_mult renamed to setsum_right_distrib.
   540 
   541 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   542 'rule' method.
   543 
   544 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   545 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   546 "=" on type bool) are handled, variable names of the form "lit_<n>"
   547 are no longer reserved, significant speedup.
   548 
   549 * Tactics 'sat' and 'satx' can now replay MiniSat proof traces.  zChaff is
   550 still supported as well.
   551 
   552 * inductive and datatype: provide projections of mutual rules, bundled
   553 as foo_bar.inducts;
   554 
   555 * Library: theory Accessible_Part has been move to main HOL.
   556 
   557 * Library: added theory Coinductive_List of potentially infinite lists
   558 as greatest fixed-point.
   559 
   560 * Library: added theory AssocList which implements (finite) maps as
   561 association lists.
   562 
   563 * New proof method "evaluation" for efficiently solving a goal
   564   (i.e. a boolean expression) by compiling it to ML. The goal is
   565   "proved" (via the oracle "Evaluation") if it evaluates to True.
   566 
   567 * Linear arithmetic now splits certain operators (e.g. min, max, abs) also
   568 when invoked by the simplifier.  This results in the simplifier being more
   569 powerful on arithmetic goals.
   570 INCOMPATIBILTY: rewrite proofs.  Set fast_arith_split_limit to 0 to obtain
   571 the old behavior.
   572 
   573 * Support for hex (0x20) and binary (0b1001) numerals. 
   574 
   575 * New method:
   576   reify eqs (t), where eqs are equations for an interpretation 
   577  I :: 'a list => 'b => 'c and t::'c is an optional parameter,
   578  computes a term s::'b and a list xs::'a list and proves the theorem
   579   I xs s = t. This is also known as reification or quoting. The resulting theorem is applied to the subgoal to substitute t with I xs s.
   580 If t is omitted, the subgoal itself is reified.
   581 
   582 * New method:
   583  reflection corr_thm eqs (t). The parameters eqs and (t) are as explained above. corr_thm is a theorem for 
   584 I vs (f t) = I vs t, where f is supposed to be a computable function (in the sense of code generattion). The method uses reify to compute s and xs as above then applies corr_thm and uses normalization by evaluation to "prove" f s = r and finally gets the theorem t = r, which is again applied to the subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   585 
   586 * Reflection: Automatic refification now handels binding, an example is available in HOL/ex/ReflectionEx.thy
   587 *** HOL-Algebra ***
   588 
   589 * Method algebra is now set up via an attribute.  For examples see CRing.thy.
   590   INCOMPATIBILITY: the method is now weaker on combinations of algebraic
   591   structures.
   592 
   593 * Formalisation of ideals and the quotient construction over rings, contributed
   594   by Stephan Hohe.
   595 
   596 * Renamed `CRing.thy' to `Ring.thy'.  INCOMPATIBILITY.
   597 
   598 *** HOL-Complex ***
   599 
   600 * Theory Real: new method ferrack implements quantifier elimination
   601 for linear arithmetic over the reals. The quantifier elimination
   602 feature is used only for decision, for compatibility with arith. This
   603 means a goal is either solved or left unchanged, no simplification.
   604 
   605 
   606 *** ML ***
   607 
   608 * Pure/General/susp.ML:
   609 
   610 New module for delayed evaluations.
   611 
   612 * Pure/library:
   613 
   614 Semantically identical functions "equal_list" and "eq_list" have been
   615 unified to "eq_list".
   616 
   617 * Pure/library:
   618 
   619   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   620   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   621 
   622 The semantics of "burrow" is: "take a function with *simulatanously*
   623 transforms a list of value, and apply it *simulatanously* to a list of
   624 list of values of the appropriate type". Confer this with "map" which
   625 would *not* apply its argument function simulatanously but in
   626 sequence. "fold_burrow" has an additional context.
   627 
   628 Both actually avoid the usage of "unflat" since they hide away
   629 "unflat" from the user.
   630 
   631 * Pure/library: functions map2 and fold2 with curried syntax for
   632 simultanous mapping and folding:
   633 
   634     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   635     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   636 
   637 * Pure/library: indexed lists - some functions in the Isabelle library
   638 treating lists over 'a as finite mappings from [0...n] to 'a have been
   639 given more convenient names and signatures reminiscent of similar
   640 functions for alists, tables, etc:
   641 
   642   val nth: 'a list -> int -> 'a 
   643   val nth_update: int * 'a -> 'a list -> 'a list
   644   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   645   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   646 
   647 Note that fold_index starts counting at index 0, not 1 like foldln
   648 used to.
   649 
   650 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   651 
   652 * Pure/General/name_mangler.ML provides a functor for generic name
   653 mangling (bijective mapping from any expression values to strings).
   654 
   655 * Pure/General/rat.ML implements rational numbers.
   656 
   657 * Pure/General/table.ML: the join operations now works via exceptions
   658 DUP/SAME instead of type option.  This is simpler in simple cases, and
   659 admits slightly more efficient complex applications.
   660 
   661 * Pure: datatype Context.generic joins theory/Proof.context and
   662 provides some facilities for code that works in either kind of
   663 context, notably GenericDataFun for uniform theory and proof data.
   664 
   665 * Pure: 'advanced' translation functions (parse_translation etc.) now
   666 use Context.generic instead of just theory.
   667 
   668 * Pure: simplified internal attribute type, which is now always
   669 Context.generic * thm -> Context.generic * thm.  Global (theory)
   670 vs. local (Proof.context) attributes have been discontinued, while
   671 minimizing code duplication.  Thm.rule_attribute and
   672 Thm.declaration_attribute build canonical attributes; see also
   673 structure Context for further operations on Context.generic, notably
   674 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   675 declarations and definitions.
   676 
   677 * Pure/kernel: consts certification ignores sort constraints given in
   678 signature declarations.  (This information is not relevant to the
   679 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   680 
   681 * Pure: axiomatic type classes are now purely definitional, with
   682 explicit proofs of class axioms and super class relations performed
   683 internally.  See Pure/axclass.ML for the main internal interfaces --
   684 notably AxClass.define_class supercedes AxClass.add_axclass, and
   685 AxClass.axiomatize_class/classrel/arity supercede
   686 Sign.add_classes/classrel/arities.
   687 
   688 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   689 global/local versions on theory vs. Proof.context have been
   690 discontinued; Attrib.syntax and Method.syntax have been adapted
   691 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   692 attributes, methods, etc.
   693 
   694 * Pure: several functions of signature "... -> theory -> theory * ..."
   695 have been reoriented to "... -> theory -> ... * theory" in order to
   696 allow natural usage in combination with the ||>, ||>>, |-> and
   697 fold_map combinators.
   698 
   699 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   700 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   701 achieve the old behaviour.
   702 
   703 * Pure: the "Goal" constant is now called "prop", supporting a
   704 slightly more general idea of ``protecting'' meta-level rule
   705 statements.
   706 
   707 * Pure: Logic.(un)varify only works in a global context, which is now
   708 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   709 Logic.legacy_(un)varify as temporary workaround.
   710 
   711 * Pure: structure Name provides scalable operations for generating
   712 internal variable names, notably Name.variants etc.  This replaces
   713 some popular functions from term.ML:
   714 
   715   Term.variant		->  Name.variant
   716   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   717   Term.invent_names	->  Name.invent_list
   718 
   719 Note that low-level renaming rarely occurs in new code -- operations
   720 from structure Variable are used instead (see below).
   721 
   722 * Pure: structure Variable provides fundamental operations for proper
   723 treatment of fixed/schematic variables in a context.  For example,
   724 Variable.import introduces fixes for schematics of given facts and
   725 Variable.export reverses the effect (up to renaming) -- this replaces
   726 various freeze_thaw operations.
   727 
   728 * Pure: structure Goal provides simple interfaces for
   729 init/conclude/finish and tactical prove operations (replacing former
   730 Tactic.prove).  Goal.prove is the canonical way to prove results
   731 within a given context; Goal.prove_global is a degraded version for
   732 theory level goals, including a global Drule.standard.  Note that
   733 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   734 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   735 in a locale context).
   736 
   737 * Isar: simplified treatment of user-level errors, using exception
   738 ERROR of string uniformly.  Function error now merely raises ERROR,
   739 without any side effect on output channels.  The Isar toplevel takes
   740 care of proper display of ERROR exceptions.  ML code may use plain
   741 handle/can/try; cat_error may be used to concatenate errors like this:
   742 
   743   ... handle ERROR msg => cat_error msg "..."
   744 
   745 Toplevel ML code (run directly or through the Isar toplevel) may be
   746 embedded into the Isar toplevel with exception display/debug like
   747 this:
   748 
   749   Isar.toplevel (fn () => ...)
   750 
   751 INCOMPATIBILITY, removed special transform_error facilities, removed
   752 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   753 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   754 -- use plain ERROR instead.
   755 
   756 * Isar: theory setup now has type (theory -> theory), instead of a
   757 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   758 
   759 * Isar: installed ML toplevel pretty printer for type Proof.context,
   760 subject to ProofContext.debug/verbose flags.
   761 
   762 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   763 theory before entering a proof state.  Transactions now always see a
   764 quasi-functional intermediate checkpoint, both in interactive and
   765 batch mode.
   766 
   767 * Simplifier: the simpset of a running simplification process now
   768 contains a proof context (cf. Simplifier.the_context), which is the
   769 very context that the initial simpset has been retrieved from (by
   770 simpset_of/local_simpset_of).  Consequently, all plug-in components
   771 (solver, looper etc.) may depend on arbitrary proof data.
   772 
   773 * Simplifier.inherit_context inherits the proof context (plus the
   774 local bounds) of the current simplification process; any simproc
   775 etc. that calls the Simplifier recursively should do this!  Removed
   776 former Simplifier.inherit_bounds, which is already included here --
   777 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   778 specify an explicit context using Simplifier.context/theory_context.
   779 
   780 * Simplifier/Classical Reasoner: more abstract interfaces
   781 change_simpset/claset for modifying the simpset/claset reference of a
   782 theory; raw versions simpset/claset_ref etc. have been discontinued --
   783 INCOMPATIBILITY.
   784 
   785 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   786 "Trueprop" etc.
   787 
   788 
   789 
   790 New in Isabelle2005 (October 2005)
   791 ----------------------------------
   792 
   793 *** General ***
   794 
   795 * Theory headers: the new header syntax for Isar theories is
   796 
   797   theory <name>
   798   imports <theory1> ... <theoryN>
   799   uses <file1> ... <fileM>
   800   begin
   801 
   802 where the 'uses' part is optional.  The previous syntax
   803 
   804   theory <name> = <theory1> + ... + <theoryN>:
   805 
   806 will disappear in the next release.  Use isatool fixheaders to convert
   807 existing theory files.  Note that there is no change in ancient
   808 non-Isar theories now, but these will disappear soon.
   809 
   810 * Theory loader: parent theories can now also be referred to via
   811 relative and absolute paths.
   812 
   813 * Command 'find_theorems' searches for a list of criteria instead of a
   814 list of constants. Known criteria are: intro, elim, dest, name:string,
   815 simp:term, and any term. Criteria can be preceded by '-' to select
   816 theorems that do not match. Intro, elim, dest select theorems that
   817 match the current goal, name:s selects theorems whose fully qualified
   818 name contain s, and simp:term selects all simplification rules whose
   819 lhs match term.  Any other term is interpreted as pattern and selects
   820 all theorems matching the pattern. Available in ProofGeneral under
   821 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   822 
   823   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   824 
   825 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   826 matching the current goal as introduction rule and not having "HOL."
   827 in their name (i.e. not being defined in theory HOL).
   828 
   829 * Command 'thms_containing' has been discontinued in favour of
   830 'find_theorems'; INCOMPATIBILITY.
   831 
   832 * Communication with Proof General is now 8bit clean, which means that
   833 Unicode text in UTF-8 encoding may be used within theory texts (both
   834 formal and informal parts).  Cf. option -U of the Isabelle Proof
   835 General interface.  Here are some simple examples (cf. src/HOL/ex):
   836 
   837   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   838   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   839 
   840 * Improved efficiency of the Simplifier and, to a lesser degree, the
   841 Classical Reasoner.  Typical big applications run around 2 times
   842 faster.
   843 
   844 
   845 *** Document preparation ***
   846 
   847 * Commands 'display_drafts' and 'print_drafts' perform simple output
   848 of raw sources.  Only those symbols that do not require additional
   849 LaTeX packages (depending on comments in isabellesym.sty) are
   850 displayed properly, everything else is left verbatim.  isatool display
   851 and isatool print are used as front ends (these are subject to the
   852 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   853 
   854 * Command tags control specific markup of certain regions of text,
   855 notably folding and hiding.  Predefined tags include "theory" (for
   856 theory begin and end), "proof" for proof commands, and "ML" for
   857 commands involving ML code; the additional tags "visible" and
   858 "invisible" are unused by default.  Users may give explicit tag
   859 specifications in the text, e.g. ''by %invisible (auto)''.  The
   860 interpretation of tags is determined by the LaTeX job during document
   861 preparation: see option -V of isatool usedir, or options -n and -t of
   862 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   863 \isadroptag.
   864 
   865 Several document versions may be produced at the same time via isatool
   866 usedir (the generated index.html will link all of them).  Typical
   867 specifications include ''-V document=theory,proof,ML'' to present
   868 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   869 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   870 these parts without any formal replacement text.  The Isabelle site
   871 default settings produce ''document'' and ''outline'' versions as
   872 specified above.
   873 
   874 * Several new antiquotations:
   875 
   876   @{term_type term} prints a term with its type annotated;
   877 
   878   @{typeof term} prints the type of a term;
   879 
   880   @{const const} is the same as @{term const}, but checks that the
   881   argument is a known logical constant;
   882 
   883   @{term_style style term} and @{thm_style style thm} print a term or
   884   theorem applying a "style" to it
   885 
   886   @{ML text}
   887 
   888 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   889 definitions, equations, inequations etc., 'concl' printing only the
   890 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   891 to print the specified premise.  TermStyle.add_style provides an ML
   892 interface for introducing further styles.  See also the "LaTeX Sugar"
   893 document practical applications.  The ML antiquotation prints
   894 type-checked ML expressions verbatim.
   895 
   896 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   897 and 'text' support optional locale specification '(in loc)', which
   898 specifies the default context for interpreting antiquotations.  For
   899 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   900 
   901 * Option 'locale=NAME' of antiquotations specifies an alternative
   902 context interpreting the subsequent argument.  For example: @{thm
   903 [locale=lattice] inf_assoc}.
   904 
   905 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   906 a proof context.
   907 
   908 * Proper output of antiquotations for theory commands involving a
   909 proof context (such as 'locale' or 'theorem (in loc) ...').
   910 
   911 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   912 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   913 
   914 * isatool usedir: new option -C (default true) controls whether option
   915 -D should include a copy of the original document directory; -C false
   916 prevents unwanted effects such as copying of administrative CVS data.
   917 
   918 
   919 *** Pure ***
   920 
   921 * Considerably improved version of 'constdefs' command.  Now performs
   922 automatic type-inference of declared constants; additional support for
   923 local structure declarations (cf. locales and HOL records), see also
   924 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   925 sequential dependencies of definitions within a single 'constdefs'
   926 section; moreover, the declared name needs to be an identifier.  If
   927 all fails, consider to fall back on 'consts' and 'defs' separately.
   928 
   929 * Improved indexed syntax and implicit structures.  First of all,
   930 indexed syntax provides a notational device for subscripted
   931 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   932 expressions.  Secondly, in a local context with structure
   933 declarations, number indexes \<^sub>n or the empty index (default
   934 number 1) refer to a certain fixed variable implicitly; option
   935 show_structs controls printing of implicit structures.  Typical
   936 applications of these concepts involve record types and locales.
   937 
   938 * New command 'no_syntax' removes grammar declarations (and
   939 translations) resulting from the given syntax specification, which is
   940 interpreted in the same manner as for the 'syntax' command.
   941 
   942 * 'Advanced' translation functions (parse_translation etc.) may depend
   943 on the signature of the theory context being presently used for
   944 parsing/printing, see also isar-ref manual.
   945 
   946 * Improved 'oracle' command provides a type-safe interface to turn an
   947 ML expression of type theory -> T -> term into a primitive rule of
   948 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   949 is already included here); see also FOL/ex/IffExample.thy;
   950 INCOMPATIBILITY.
   951 
   952 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   953 before); "cI" is no longer bound, use "c.intro" instead.
   954 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   955 axclasses vs. locales.
   956 
   957 * Improved internal renaming of symbolic identifiers -- attach primes
   958 instead of base 26 numbers.
   959 
   960 * New flag show_question_marks controls printing of leading question
   961 marks in schematic variable names.
   962 
   963 * In schematic variable names, *any* symbol following \<^isub> or
   964 \<^isup> is now treated as part of the base name.  For example, the
   965 following works without printing of awkward ".0" indexes:
   966 
   967   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   968     by simp
   969 
   970 * Inner syntax includes (*(*nested*) comments*).
   971 
   972 * Pretty printer now supports unbreakable blocks, specified in mixfix
   973 annotations as "(00...)".
   974 
   975 * Clear separation of logical types and nonterminals, where the latter
   976 may only occur in 'syntax' specifications or type abbreviations.
   977 Before that distinction was only partially implemented via type class
   978 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   979 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   980 exotic syntax specifications may require further adaption
   981 (e.g. Cube/Cube.thy).
   982 
   983 * Removed obsolete type class "logic", use the top sort {} instead.
   984 Note that non-logical types should be declared as 'nonterminals'
   985 rather than 'types'.  INCOMPATIBILITY for new object-logic
   986 specifications.
   987 
   988 * Attributes 'induct' and 'cases': type or set names may now be
   989 locally fixed variables as well.
   990 
   991 * Simplifier: can now control the depth to which conditional rewriting
   992 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   993 Limit.
   994 
   995 * Simplifier: simplification procedures may now take the current
   996 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   997 interface), which is very useful for calling the Simplifier
   998 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   999 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1000 low-level mk_simproc no longer applies Logic.varify internally, to
  1001 allow for use in a context of fixed variables.
  1002 
  1003 * thin_tac now works even if the assumption being deleted contains !!
  1004 or ==>.  More generally, erule now works even if the major premise of
  1005 the elimination rule contains !! or ==>.
  1006 
  1007 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1008 
  1009 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1010 from Pure, which contains all common declarations already.  Both
  1011 theories are defined via plain Isabelle/Isar .thy files.
  1012 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1013 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1014 use isatool fixcpure to adapt your theory and ML sources.
  1015 
  1016 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1017 selections of theorems in named facts via index ranges.
  1018 
  1019 * 'print_theorems': in theory mode, really print the difference
  1020 wrt. the last state (works for interactive theory development only),
  1021 in proof mode print all local facts (cf. 'print_facts');
  1022 
  1023 * 'hide': option '(open)' hides only base names.
  1024 
  1025 * More efficient treatment of intermediate checkpoints in interactive
  1026 theory development.
  1027 
  1028 * Code generator is now invoked via code_module (incremental code
  1029 generation) and code_library (modular code generation, ML structures
  1030 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1031 must be quoted when used as identifiers.
  1032 
  1033 * New 'value' command for reading, evaluating and printing terms using
  1034 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1035 quoted when used as identifier.
  1036 
  1037 
  1038 *** Locales ***
  1039 
  1040 * New commands for the interpretation of locale expressions in
  1041 theories (1), locales (2) and proof contexts (3).  These generate
  1042 proof obligations from the expression specification.  After the
  1043 obligations have been discharged, theorems of the expression are added
  1044 to the theory, target locale or proof context.  The synopsis of the
  1045 commands is a follows:
  1046 
  1047   (1) interpretation expr inst
  1048   (2) interpretation target < expr
  1049   (3) interpret expr inst
  1050 
  1051 Interpretation in theories and proof contexts require a parameter
  1052 instantiation of terms from the current context.  This is applied to
  1053 specifications and theorems of the interpreted expression.
  1054 Interpretation in locales only permits parameter renaming through the
  1055 locale expression.  Interpretation is smart in that interpretations
  1056 that are active already do not occur in proof obligations, neither are
  1057 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1058 inspect active interpretations of a particular locale.  For details,
  1059 see the Isar Reference manual.  Examples can be found in
  1060 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1061 
  1062 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1063 'interpret' instead.
  1064 
  1065 * New context element 'constrains' for adding type constraints to
  1066 parameters.
  1067 
  1068 * Context expressions: renaming of parameters with syntax
  1069 redeclaration.
  1070 
  1071 * Locale declaration: 'includes' disallowed.
  1072 
  1073 * Proper static binding of attribute syntax -- i.e. types / terms /
  1074 facts mentioned as arguments are always those of the locale definition
  1075 context, independently of the context of later invocations.  Moreover,
  1076 locale operations (renaming and type / term instantiation) are applied
  1077 to attribute arguments as expected.
  1078 
  1079 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1080 actual attributes; rare situations may require Attrib.attribute to
  1081 embed those attributes into Attrib.src that lack concrete syntax.
  1082 Attribute implementations need to cooperate properly with the static
  1083 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1084 Attrib.XXX_thm etc. already do the right thing without further
  1085 intervention.  Only unusual applications -- such as "where" or "of"
  1086 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1087 on the context and the facts involved -- may have to assign parsed
  1088 values to argument tokens explicitly.
  1089 
  1090 * Changed parameter management in theorem generation for long goal
  1091 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1092 theorem statement in rare situations.
  1093 
  1094 * Locale inspection command 'print_locale' omits notes elements.  Use
  1095 'print_locale!' to have them included in the output.
  1096 
  1097 
  1098 *** Provers ***
  1099 
  1100 * Provers/hypsubst.ML: improved version of the subst method, for
  1101 single-step rewriting: it now works in bound variable contexts. New is
  1102 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1103 rewrite a different subterm than the original subst method, which is
  1104 still available as 'simplesubst'.
  1105 
  1106 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1107 and quasi orders.
  1108 
  1109 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1110 reflexive-transitive closure of relations.
  1111 
  1112 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1113 limit (previously hard-coded with a value of 20) user-definable.
  1114 
  1115 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1116 is peformed already.  Object-logics merely need to finish their
  1117 initial simpset configuration as before.  INCOMPATIBILITY.
  1118 
  1119 
  1120 *** HOL ***
  1121 
  1122 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1123 
  1124   syntax (epsilon)
  1125     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1126 
  1127 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1128 and x-symbol; use option '-m epsilon' to get it actually printed.
  1129 Moreover, the mathematically important symbolic identifier \<epsilon>
  1130 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1131 
  1132 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1133 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1134 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1135 support corresponding Isar calculations.
  1136 
  1137 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1138 instead of ":".
  1139 
  1140 * theory SetInterval: changed the syntax for open intervals:
  1141 
  1142   Old       New
  1143   {..n(}    {..<n}
  1144   {)n..}    {n<..}
  1145   {m..n(}   {m..<n}
  1146   {)m..n}   {m<..n}
  1147   {)m..n(}  {m<..<n}
  1148 
  1149 The old syntax is still supported but will disappear in the next
  1150 release.  For conversion use the following Emacs search and replace
  1151 patterns (these are not perfect but work quite well):
  1152 
  1153   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1154   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1155 
  1156 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1157 equalities in commutative rings; method 'algebra' provides a generic
  1158 interface.
  1159 
  1160 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1161 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1162 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1163 be a tuple pattern.
  1164 
  1165 Some new syntax forms are available:
  1166 
  1167   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1168   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1169   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1170   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1171 
  1172 The latter form "\<Sum>x < k. e" used to be based on a separate
  1173 function "Summation", which has been discontinued.
  1174 
  1175 * theory Finite_Set: in structured induction proofs, the insert case
  1176 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1177 (insert F x)'.
  1178 
  1179 * The 'refute' command has been extended to support a much larger
  1180 fragment of HOL, including axiomatic type classes, constdefs and
  1181 typedefs, inductive datatypes and recursion.
  1182 
  1183 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1184 Requires zChaff with proof generation to be installed.  See
  1185 HOL/ex/SAT_Examples.thy for examples.
  1186 
  1187 * Datatype induction via method 'induct' now preserves the name of the
  1188 induction variable. For example, when proving P(xs::'a list) by
  1189 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1190 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1191 in unstructured proof scripts.
  1192 
  1193 * Reworked implementation of records.  Improved scalability for
  1194 records with many fields, avoiding performance problems for type
  1195 inference. Records are no longer composed of nested field types, but
  1196 of nested extension types. Therefore the record type only grows linear
  1197 in the number of extensions and not in the number of fields.  The
  1198 top-level (users) view on records is preserved.  Potential
  1199 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1200 old record representation. The type generated for a record is called
  1201 <record_name>_ext_type.
  1202 
  1203 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1204 proofs triggered by a record definition or a simproc (if
  1205 quick_and_dirty is enabled).  Definitions of large records can take
  1206 quite long.
  1207 
  1208 New simproc record_upd_simproc for simplification of multiple record
  1209 updates enabled by default.  Moreover, trivial updates are also
  1210 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1211 occasionally, since simplification is more powerful by default.
  1212 
  1213 * typedef: proper support for polymorphic sets, which contain extra
  1214 type-variables in the term.
  1215 
  1216 * Simplifier: automatically reasons about transitivity chains
  1217 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1218 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1219 old proofs break occasionally as simplification may now solve more
  1220 goals than previously.
  1221 
  1222 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1223 present.  Works for all partial orders (class "order"), in particular
  1224 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1225 just like y <= x.
  1226 
  1227 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1228 bound variable or a constant then the let is unfolded.  Otherwise
  1229 first a is simplified to b, and then f b is simplified to g. If
  1230 possible we abstract b from g arriving at "let x = b in h x",
  1231 otherwise we unfold the let and arrive at g.  The simproc can be
  1232 enabled/disabled by the reference use_let_simproc.  Potential
  1233 INCOMPATIBILITY since simplification is more powerful by default.
  1234 
  1235 * Classical reasoning: the meson method now accepts theorems as arguments.
  1236 
  1237 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1238 jobs to provide advice on the provability of subgoals.
  1239 
  1240 * Theory OrderedGroup and Ring_and_Field: various additions and
  1241 improvements to faciliate calculations involving equalities and
  1242 inequalities.
  1243 
  1244 The following theorems have been eliminated or modified
  1245 (INCOMPATIBILITY):
  1246 
  1247   abs_eq             now named abs_of_nonneg
  1248   abs_of_ge_0        now named abs_of_nonneg
  1249   abs_minus_eq       now named abs_of_nonpos
  1250   imp_abs_id         now named abs_of_nonneg
  1251   imp_abs_neg_id     now named abs_of_nonpos
  1252   mult_pos           now named mult_pos_pos
  1253   mult_pos_le        now named mult_nonneg_nonneg
  1254   mult_pos_neg_le    now named mult_nonneg_nonpos
  1255   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1256   mult_neg           now named mult_neg_neg
  1257   mult_neg_le        now named mult_nonpos_nonpos
  1258 
  1259 * Theory Parity: added rules for simplifying exponents.
  1260 
  1261 * Theory List:
  1262 
  1263 The following theorems have been eliminated or modified
  1264 (INCOMPATIBILITY):
  1265 
  1266   list_all_Nil       now named list_all.simps(1)
  1267   list_all_Cons      now named list_all.simps(2)
  1268   list_all_conv      now named list_all_iff
  1269   set_mem_eq         now named mem_iff
  1270 
  1271 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1272 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1273 
  1274 
  1275 *** HOL-Complex ***
  1276 
  1277 * Theory RealDef: better support for embedding natural numbers and
  1278 integers in the reals.
  1279 
  1280 The following theorems have been eliminated or modified
  1281 (INCOMPATIBILITY):
  1282 
  1283   exp_ge_add_one_self  now requires no hypotheses
  1284   real_of_int_add      reversed direction of equality (use [symmetric])
  1285   real_of_int_minus    reversed direction of equality (use [symmetric])
  1286   real_of_int_diff     reversed direction of equality (use [symmetric])
  1287   real_of_int_mult     reversed direction of equality (use [symmetric])
  1288 
  1289 * Theory RComplete: expanded support for floor and ceiling functions.
  1290 
  1291 * Theory Ln is new, with properties of the natural logarithm
  1292 
  1293 * Hyperreal: There is a new type constructor "star" for making
  1294 nonstandard types.  The old type names are now type synonyms:
  1295 
  1296   hypreal = real star
  1297   hypnat = nat star
  1298   hcomplex = complex star
  1299 
  1300 * Hyperreal: Many groups of similarly-defined constants have been
  1301 replaced by polymorphic versions (INCOMPATIBILITY):
  1302 
  1303   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1304 
  1305   starset      <-- starsetNat, starsetC
  1306   *s*          <-- *sNat*, *sc*
  1307   starset_n    <-- starsetNat_n, starsetC_n
  1308   *sn*         <-- *sNatn*, *scn*
  1309   InternalSets <-- InternalNatSets, InternalCSets
  1310 
  1311   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1312   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1313   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1314   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1315   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1316 
  1317 * Hyperreal: Many type-specific theorems have been removed in favor of
  1318 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1319 
  1320   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1321   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1322   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1323   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1324   right_minus <-- hypreal_add_minus
  1325   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1326   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1327   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1328   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1329   mult_1_right <-- hcomplex_mult_one_right
  1330   mult_zero_left <-- hcomplex_mult_zero_left
  1331   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1332   right_distrib <-- hypnat_add_mult_distrib2
  1333   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1334   right_inverse <-- hypreal_mult_inverse
  1335   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1336   order_refl <-- {hypreal,hypnat}_le_refl
  1337   order_trans <-- {hypreal,hypnat}_le_trans
  1338   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1339   order_less_le <-- {hypreal,hypnat}_less_le
  1340   linorder_linear <-- {hypreal,hypnat}_le_linear
  1341   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1342   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1343   add_nonneg_nonneg <-- hypreal_le_add_order
  1344 
  1345 * Hyperreal: Separate theorems having to do with type-specific
  1346 versions of constants have been merged into theorems that apply to the
  1347 new polymorphic constants (INCOMPATIBILITY):
  1348 
  1349   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1350   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1351   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1352   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1353   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1354   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1355   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1356   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1357   STAR_diff <-- {STAR,STARC}_diff
  1358   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1359     STARC_hcomplex_of_complex}_image_subset
  1360   starset_n_Un <-- starset{Nat,C}_n_Un
  1361   starset_n_Int <-- starset{Nat,C}_n_Int
  1362   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1363   starset_n_diff <-- starset{Nat,C}_n_diff
  1364   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1365   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1366   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1367   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1368   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1369   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1370   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1371   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1372   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1373   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1374   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1375   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1376   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1377   starfun_diff <-- starfun{C,RC,CR}_diff
  1378   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1379   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1380   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1381   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1382   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1383   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1384   starfun_Id <-- starfunC_Id
  1385   starfun_approx <-- starfun{Nat,CR}_approx
  1386   starfun_capprox <-- starfun{C,RC}_capprox
  1387   starfun_abs <-- starfunNat_rabs
  1388   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1389   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1390   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1391   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1392   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1393   starfun_add_approx <-- starfunCR_add_approx
  1394   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1395   starfun_divide <-- starfun{C,CR,RC}_divide
  1396   starfun_n <-- starfun{Nat,C}_n
  1397   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1398   starfun_n_add <-- starfun{Nat,C}_n_add
  1399   starfun_n_add_minus <-- starfunNat_n_add_minus
  1400   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1401   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1402   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1403 
  1404   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1405   star_n_minus <-- {hypreal,hcomplex}_minus
  1406   star_n_diff <-- {hypreal,hcomplex}_diff
  1407   star_n_mult <-- {hypreal,hcomplex}_mult
  1408   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1409   star_n_le <-- {hypreal,hypnat}_le
  1410   star_n_less <-- {hypreal,hypnat}_less
  1411   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1412   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1413   star_n_abs <-- hypreal_hrabs
  1414   star_n_divide <-- hcomplex_divide
  1415 
  1416   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1417   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1418   star_of_diff <-- hypreal_of_real_diff
  1419   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1420   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1421   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1422   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1423   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1424   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1425   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1426   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1427   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1428   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1429   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1430   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1431   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1432   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1433   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1434   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1435   star_of_power <-- hypreal_of_real_power
  1436   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1437 
  1438 * Hyperreal: new method "transfer" that implements the transfer
  1439 principle of nonstandard analysis. With a subgoal that mentions
  1440 nonstandard types like "'a star", the command "apply transfer"
  1441 replaces it with an equivalent one that mentions only standard types.
  1442 To be successful, all free variables must have standard types; non-
  1443 standard variables must have explicit universal quantifiers.
  1444 
  1445 * Hyperreal: A theory of Taylor series.
  1446 
  1447 
  1448 *** HOLCF ***
  1449 
  1450 * Discontinued special version of 'constdefs' (which used to support
  1451 continuous functions) in favor of the general Pure one with full
  1452 type-inference.
  1453 
  1454 * New simplification procedure for solving continuity conditions; it
  1455 is much faster on terms with many nested lambda abstractions (cubic
  1456 instead of exponential time).
  1457 
  1458 * New syntax for domain package: selector names are now optional.
  1459 Parentheses should be omitted unless argument is lazy, for example:
  1460 
  1461   domain 'a stream = cons "'a" (lazy "'a stream")
  1462 
  1463 * New command 'fixrec' for defining recursive functions with pattern
  1464 matching; defining multiple functions with mutual recursion is also
  1465 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1466 sinr, or any data constructor defined by the domain package. The given
  1467 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1468 syntax and examples.
  1469 
  1470 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1471 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1472 but the proof obligation additionally includes an admissibility
  1473 requirement. The packages generate instances of class cpo or pcpo,
  1474 with continuity and strictness theorems for Rep and Abs.
  1475 
  1476 * HOLCF: Many theorems have been renamed according to a more standard naming
  1477 scheme (INCOMPATIBILITY):
  1478 
  1479   foo_inject:  "foo$x = foo$y ==> x = y"
  1480   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1481   foo_less:    "(foo$x << foo$y) = (x << y)"
  1482   foo_strict:  "foo$UU = UU"
  1483   foo_defined: "... ==> foo$x ~= UU"
  1484   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1485 
  1486 
  1487 *** ZF ***
  1488 
  1489 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1490 including the First Isomorphism Theorem (on quotienting by the kernel
  1491 of a homomorphism).
  1492 
  1493 * ZF/Simplifier: install second copy of type solver that actually
  1494 makes use of TC rules declared to Isar proof contexts (or locales);
  1495 the old version is still required for ML proof scripts.
  1496 
  1497 
  1498 *** Cube ***
  1499 
  1500 * Converted to Isar theory format; use locales instead of axiomatic
  1501 theories.
  1502 
  1503 
  1504 *** ML ***
  1505 
  1506 * Pure/library.ML no longer defines its own option datatype, but uses
  1507 that of the SML basis, which has constructors NONE and SOME instead of
  1508 None and Some, as well as exception Option.Option instead of OPTION.
  1509 The functions the, if_none, is_some, is_none have been adapted
  1510 accordingly, while Option.map replaces apsome.
  1511 
  1512 * Pure/library.ML: the exception LIST has been given up in favour of
  1513 the standard exceptions Empty and Subscript, as well as
  1514 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1515 superceded by the standard hd and tl functions etc.
  1516 
  1517 A number of basic list functions are no longer exported to the ML
  1518 toplevel, as they are variants of predefined functions.  The following
  1519 suggests how one can translate existing code:
  1520 
  1521     rev_append xs ys = List.revAppend (xs, ys)
  1522     nth_elem (i, xs) = List.nth (xs, i)
  1523     last_elem xs = List.last xs
  1524     flat xss = List.concat xss
  1525     seq fs = List.app fs
  1526     partition P xs = List.partition P xs
  1527     mapfilter f xs = List.mapPartial f xs
  1528 
  1529 * Pure/library.ML: several combinators for linear functional
  1530 transformations, notably reverse application and composition:
  1531 
  1532   x |> f                f #> g
  1533   (x, y) |-> f          f #-> g
  1534 
  1535 * Pure/library.ML: introduced/changed precedence of infix operators:
  1536 
  1537   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1538   infix 2 ?;
  1539   infix 3 o oo ooo oooo;
  1540   infix 4 ~~ upto downto;
  1541 
  1542 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1543 infix operators.
  1544 
  1545 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1546 fold_map support linear functional transformations and nesting.  For
  1547 example:
  1548 
  1549   fold f [x1, ..., xN] y =
  1550     y |> f x1 |> ... |> f xN
  1551 
  1552   (fold o fold) f [xs1, ..., xsN] y =
  1553     y |> fold f xs1 |> ... |> fold f xsN
  1554 
  1555   fold f [x1, ..., xN] =
  1556     f x1 #> ... #> f xN
  1557 
  1558   (fold o fold) f [xs1, ..., xsN] =
  1559     fold f xs1 #> ... #> fold f xsN
  1560 
  1561 * Pure/library.ML: the following selectors on type 'a option are
  1562 available:
  1563 
  1564   the:               'a option -> 'a  (*partial*)
  1565   these:             'a option -> 'a  where 'a = 'b list
  1566   the_default: 'a -> 'a option -> 'a
  1567   the_list:          'a option -> 'a list
  1568 
  1569 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1570 basic operations for association lists, following natural argument
  1571 order; moreover the explicit equality predicate passed here avoids
  1572 potentially expensive polymorphic runtime equality checks.
  1573 The old functions may be expressed as follows:
  1574 
  1575   assoc = uncurry (AList.lookup (op =))
  1576   assocs = these oo AList.lookup (op =)
  1577   overwrite = uncurry (AList.update (op =)) o swap
  1578 
  1579 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1580 
  1581   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1582   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1583 
  1584 replacing make_keylist and keyfilter (occassionally used)
  1585 Naive rewrites:
  1586 
  1587   make_keylist = AList.make
  1588   keyfilter = AList.find (op =)
  1589 
  1590 * eq_fst and eq_snd now take explicit equality parameter, thus
  1591   avoiding eqtypes. Naive rewrites:
  1592 
  1593     eq_fst = eq_fst (op =)
  1594     eq_snd = eq_snd (op =)
  1595 
  1596 * Removed deprecated apl and apr (rarely used).
  1597   Naive rewrites:
  1598 
  1599     apl (n, op) =>>= curry op n
  1600     apr (op, m) =>>= fn n => op (n, m)
  1601 
  1602 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1603 provides a reasonably efficient light-weight implementation of sets as
  1604 lists.
  1605 
  1606 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1607 few new operations; existing lookup and update are now curried to
  1608 follow natural argument order (for use with fold etc.);
  1609 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1610 
  1611 * Pure/General: output via the Isabelle channels of
  1612 writeln/warning/error etc. is now passed through Output.output, with a
  1613 hook for arbitrary transformations depending on the print_mode
  1614 (cf. Output.add_mode -- the first active mode that provides a output
  1615 function wins).  Already formatted output may be embedded into further
  1616 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1617 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1618 accommodate easy composition of diagnostic messages etc.  Programmers
  1619 rarely need to care about Output.output or Output.raw at all, with
  1620 some notable exceptions: Output.output is required when bypassing the
  1621 standard channels (writeln etc.), or in token translations to produce
  1622 properly formatted results; Output.raw is required when capturing
  1623 already output material that will eventually be presented to the user
  1624 a second time.  For the default print mode, both Output.output and
  1625 Output.raw have no effect.
  1626 
  1627 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1628 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1629 cumulative results are displayed at the end of a batch session.
  1630 
  1631 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1632 replaced by File.platform_path and File.shell_path (with appropriate
  1633 hooks).  This provides a clean interface for unusual systems where the
  1634 internal and external process view of file names are different.
  1635 
  1636 * Pure: more efficient orders for basic syntactic entities: added
  1637 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1638 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1639 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1640 orders now -- potential INCOMPATIBILITY for code that depends on a
  1641 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1642 Library.sort_strings on result).
  1643 
  1644 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1645 fold_types traverse types/terms from left to right, observing natural
  1646 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1647 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1648 
  1649 * Pure: name spaces have been refined, with significant changes of the
  1650 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1651 to extern(_table).  The plain name entry path is superceded by a
  1652 general 'naming' context, which also includes the 'policy' to produce
  1653 a fully qualified name and external accesses of a fully qualified
  1654 name; NameSpace.extend is superceded by context dependent
  1655 Sign.declare_name.  Several theory and proof context operations modify
  1656 the naming context.  Especially note Theory.restore_naming and
  1657 ProofContext.restore_naming to get back to a sane state; note that
  1658 Theory.add_path is no longer sufficient to recover from
  1659 Theory.absolute_path in particular.
  1660 
  1661 * Pure: new flags short_names (default false) and unique_names
  1662 (default true) for controlling output of qualified names.  If
  1663 short_names is set, names are printed unqualified.  If unique_names is
  1664 reset, the name prefix is reduced to the minimum required to achieve
  1665 the original result when interning again, even if there is an overlap
  1666 with earlier declarations.
  1667 
  1668 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1669 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1670 (useful for printing error messages).  INCOMPATIBILITY.
  1671 
  1672 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1673 Theory.theory are now identified, referring to the universal
  1674 Context.theory (see Pure/context.ML).  Actual signature and theory
  1675 content is managed as theory data.  The old code and interfaces were
  1676 spread over many files and structures; the new arrangement introduces
  1677 considerable INCOMPATIBILITY to gain more clarity:
  1678 
  1679   Context -- theory management operations (name, identity, inclusion,
  1680     parents, ancestors, merge, etc.), plus generic theory data;
  1681 
  1682   Sign -- logical signature and syntax operations (declaring consts,
  1683     types, etc.), plus certify/read for common entities;
  1684 
  1685   Theory -- logical theory operations (stating axioms, definitions,
  1686     oracles), plus a copy of logical signature operations (consts,
  1687     types, etc.); also a few basic management operations (Theory.copy,
  1688     Theory.merge, etc.)
  1689 
  1690 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1691 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1692 for convenience -- they merely return the theory.
  1693 
  1694 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1695 
  1696 * Pure: the Isar proof context type is already defined early in Pure
  1697 as Context.proof (note that ProofContext.context and Proof.context are
  1698 aliases, where the latter is the preferred name).  This enables other
  1699 Isabelle components to refer to that type even before Isar is present.
  1700 
  1701 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1702 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1703 any of these kinds.  For example, Sign.intern typeK is now
  1704 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1705 Theory.hide_types.  Also note that former
  1706 Theory.hide_classes/types/consts are now
  1707 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1708 internalize their arguments!  INCOMPATIBILITY.
  1709 
  1710 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1711 datatype thmref (with constructors Name and NameSelection) instead of
  1712 plain string -- INCOMPATIBILITY;
  1713 
  1714 * Pure: cases produced by proof methods specify options, where NONE
  1715 means to remove case bindings -- INCOMPATIBILITY in
  1716 (RAW_)METHOD_CASES.
  1717 
  1718 * Pure: the following operations retrieve axioms or theorems from a
  1719 theory node or theory hierarchy, respectively:
  1720 
  1721   Theory.axioms_of: theory -> (string * term) list
  1722   Theory.all_axioms_of: theory -> (string * term) list
  1723   PureThy.thms_of: theory -> (string * thm) list
  1724   PureThy.all_thms_of: theory -> (string * thm) list
  1725 
  1726 * Pure: print_tac now outputs the goal through the trace channel.
  1727 
  1728 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1729 Reference Toplevel.debug (default false) controls detailed printing
  1730 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1731 controls execution profiling -- set to 1 for time and 2 for space
  1732 (both increase the runtime).
  1733 
  1734 * Isar session: The initial use of ROOT.ML is now always timed,
  1735 i.e. the log will show the actual process times, in contrast to the
  1736 elapsed wall-clock time that the outer shell wrapper produces.
  1737 
  1738 * Simplifier: improved handling of bound variables (nameless
  1739 representation, avoid allocating new strings).  Simprocs that invoke
  1740 the Simplifier recursively should use Simplifier.inherit_bounds to
  1741 avoid local name clashes.  Failure to do so produces warnings
  1742 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1743 for further details.
  1744 
  1745 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1746 bindings for all theorems stored within a given theory; this may help
  1747 in porting non-Isar theories to Isar ones, while keeping ML proof
  1748 scripts for the time being.
  1749 
  1750 * ML operator HTML.with_charset specifies the charset begin used for
  1751 generated HTML files.  For example:
  1752 
  1753   HTML.with_charset "utf-8" use_thy "Hebrew";
  1754   HTML.with_charset "utf-8" use_thy "Chinese";
  1755 
  1756 
  1757 *** System ***
  1758 
  1759 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1760 isabelle, isatool etc.).
  1761 
  1762 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1763 isatool doc, isatool mkdir, display_drafts etc.).
  1764 
  1765 * isatool usedir: option -f allows specification of the ML file to be
  1766 used by Isabelle; default is ROOT.ML.
  1767 
  1768 * New isatool version outputs the version identifier of the Isabelle
  1769 distribution being used.
  1770 
  1771 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1772 (containing Boolean satisfiability problems) into Isabelle/HOL
  1773 theories.
  1774 
  1775 
  1776 
  1777 New in Isabelle2004 (April 2004)
  1778 --------------------------------
  1779 
  1780 *** General ***
  1781 
  1782 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1783   Replaces linorder.ML.
  1784 
  1785 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1786   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1787   (\<a>...\<z>), are now considered normal letters, and can therefore
  1788   be used anywhere where an ASCII letter (a...zA...Z) has until
  1789   now. COMPATIBILITY: This obviously changes the parsing of some
  1790   terms, especially where a symbol has been used as a binder, say
  1791   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1792   as an identifier.  Fix it by inserting a space around former
  1793   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1794   existing theory and ML files.
  1795 
  1796 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1797 
  1798 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1799   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1800   a normal (but invisible) letter. For multiple letter subscripts repeat
  1801   \<^isub> like this: x\<^isub>1\<^isub>2.
  1802 
  1803 * Pure: There are now sub-/superscripts that can span more than one
  1804   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1805   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1806   superscript. The new control characters are not identifier parts.
  1807 
  1808 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1809   content of "..." to the latex file instead of \isacntrl... . The "..."
  1810   may consist of any printable characters excluding the end bracket >.
  1811 
  1812 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1813   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1814   declare constants "final", which prevents their being given a definition
  1815   later.  It is useful for constants whose behaviour is fixed axiomatically
  1816   rather than definitionally, such as the meta-logic connectives.
  1817 
  1818 * Pure: 'instance' now handles general arities with general sorts
  1819   (i.e. intersections of classes),
  1820 
  1821 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1822   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1823   It can be changed to alter the colors/layout of generated pages.
  1824 
  1825 
  1826 *** Isar ***
  1827 
  1828 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1829   cut_tac, subgoal_tac and thin_tac:
  1830   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1831     locales are no longer forced to write Isar proof scripts.
  1832     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1833     emulations.
  1834   - INCOMPATIBILITY: names of variables to be instantiated may no
  1835     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1836     This is consistent with the instantiation attribute "where".
  1837 
  1838 * Attributes "where" and "of":
  1839   - Now take type variables of instantiated theorem into account when reading
  1840     the instantiation string.  This fixes a bug that caused instantiated
  1841     theorems to have too special types in some circumstances.
  1842   - "where" permits explicit instantiations of type variables.
  1843 
  1844 * Calculation commands "moreover" and "also" no longer interfere with
  1845   current facts ("this"), admitting arbitrary combinations with "then"
  1846   and derived forms.
  1847 
  1848 * Locales:
  1849   - Goal statements involving the context element "includes" no longer
  1850     generate theorems with internal delta predicates (those ending on
  1851     "_axioms") in the premise.
  1852     Resolve particular premise with <locale>.intro to obtain old form.
  1853   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1854     specification and "includes" elements in goal statement.
  1855   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1856     [intro?] and [elim?] (respectively) by default.
  1857   - Experimental command for instantiation of locales in proof contexts:
  1858         instantiate <label>[<attrs>]: <loc>
  1859     Instantiates locale <loc> and adds all its theorems to the current context
  1860     taking into account their attributes.  Label and attrs are optional
  1861     modifiers, like in theorem declarations.  If present, names of
  1862     instantiated theorems are qualified with <label>, and the attributes
  1863     <attrs> are applied after any attributes these theorems might have already.
  1864       If the locale has assumptions, a chained fact of the form
  1865     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1866     are derived.  The command does not support old-style locales declared
  1867     with "locale (open)".
  1868       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1869 
  1870 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1871   (Isar) contexts.
  1872 
  1873 
  1874 *** HOL ***
  1875 
  1876 * Proof import: new image HOL4 contains the imported library from
  1877   the HOL4 system with about 2500 theorems. It is imported by
  1878   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1879   can be used like any other Isabelle image.  See
  1880   HOL/Import/HOL/README for more information.
  1881 
  1882 * Simplifier:
  1883   - Much improved handling of linear and partial orders.
  1884     Reasoners for linear and partial orders are set up for type classes
  1885     "linorder" and "order" respectively, and are added to the default simpset
  1886     as solvers.  This means that the simplifier can build transitivity chains
  1887     to solve goals from the assumptions.
  1888   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1889     of blast or auto after simplification become unnecessary because the goal
  1890     is solved by simplification already.
  1891 
  1892 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1893     all proved in axiomatic type classes for semirings, rings and fields.
  1894 
  1895 * Numerics:
  1896   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1897     now formalized using the Ring_and_Field theory mentioned above.
  1898   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1899     than before, because now they are set up once in a generic manner.
  1900   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1901     Look for the general versions in Ring_and_Field (and Power if they concern
  1902     exponentiation).
  1903 
  1904 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1905 
  1906 * Records:
  1907   - Record types are now by default printed with their type abbreviation
  1908     instead of the list of all field types. This can be configured via
  1909     the reference "print_record_type_abbr".
  1910   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1911     (not enabled by default).
  1912   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1913     EX x. x = sel r to True (not enabled by default).
  1914   - Tactic "record_split_simp_tac" to split and simplify records added.
  1915 
  1916 * 'specification' command added, allowing for definition by
  1917   specification.  There is also an 'ax_specification' command that
  1918   introduces the new constants axiomatically.
  1919 
  1920 * arith(_tac) is now able to generate counterexamples for reals as well.
  1921 
  1922 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1923 
  1924 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1925   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1926 
  1927 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1928   matrix theory to linear programming.
  1929 
  1930 * Unions and Intersections:
  1931   The latex output syntax of UN and INT has been changed
  1932   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1933   i.e. the index formulae has become a subscript.
  1934   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1935 
  1936 * Unions and Intersections over Intervals:
  1937   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1938   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1939   like in normal math, and corresponding versions for < and for intersection.
  1940 
  1941 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1942   lexicographic dictonary ordering has been added as "lexord".
  1943 
  1944 * ML: the legacy theory structures Int and List have been removed. They had
  1945   conflicted with ML Basis Library structures having the same names.
  1946 
  1947 * 'refute' command added to search for (finite) countermodels.  Only works
  1948   for a fragment of HOL.  The installation of an external SAT solver is
  1949   highly recommended.  See "HOL/Refute.thy" for details.
  1950 
  1951 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1952   formulae under an assignment of free variables to random values.
  1953   In contrast to 'refute', it can deal with inductive datatypes,
  1954   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1955   for examples.
  1956 
  1957 
  1958 *** HOLCF ***
  1959 
  1960 * Streams now come with concatenation and are part of the HOLCF image
  1961 
  1962 
  1963 
  1964 New in Isabelle2003 (May 2003)
  1965 ------------------------------
  1966 
  1967 *** General ***
  1968 
  1969 * Provers/simplifier:
  1970 
  1971   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  1972     Assumptions are now subject to complete mutual simplification,
  1973     not just from left to right. The simplifier now preserves
  1974     the order of assumptions.
  1975 
  1976     Potential INCOMPATIBILITY:
  1977 
  1978     -- simp sometimes diverges where the old version did
  1979        not, e.g. invoking simp on the goal
  1980 
  1981         [| P (f x); y = x; f x = f y |] ==> Q
  1982 
  1983        now gives rise to the infinite reduction sequence
  1984 
  1985         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  1986 
  1987        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  1988        kind of problem.
  1989 
  1990     -- Tactics combining classical reasoner and simplification (such as auto)
  1991        are also affected by this change, because many of them rely on
  1992        simp. They may sometimes diverge as well or yield a different numbers
  1993        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  1994        in case of problems. Sometimes subsequent calls to the classical
  1995        reasoner will fail because a preceeding call to the simplifier too
  1996        eagerly simplified the goal, e.g. deleted redundant premises.
  1997 
  1998   - The simplifier trace now shows the names of the applied rewrite rules
  1999 
  2000   - You can limit the number of recursive invocations of the simplifier
  2001     during conditional rewriting (where the simplifie tries to solve the
  2002     conditions before applying the rewrite rule):
  2003     ML "simp_depth_limit := n"
  2004     where n is an integer. Thus you can force termination where previously
  2005     the simplifier would diverge.
  2006 
  2007   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2008 
  2009   - No longer aborts on failed congruence proof.  Instead, the
  2010     congruence is ignored.
  2011 
  2012 * Pure: New generic framework for extracting programs from constructive
  2013   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2014   as HOL/Extraction for some case studies.
  2015 
  2016 * Pure: The main goal of the proof state is no longer shown by default, only
  2017 the subgoals. This behaviour is controlled by a new flag.
  2018    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2019 (ML: Proof.show_main_goal).
  2020 
  2021 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2022 rules whose conclusion matches subgoal 1:
  2023       PG menu: Isabelle/Isar -> Show me -> matching rules
  2024 The rules are ordered by how closely they match the subgoal.
  2025 In particular, rules that solve a subgoal outright are displayed first
  2026 (or rather last, the way they are printed).
  2027 (ML: ProofGeneral.print_intros())
  2028 
  2029 * Pure: New flag trace_unify_fail causes unification to print
  2030 diagnostic information (PG: in trace buffer) when it fails. This is
  2031 useful for figuring out why single step proofs like rule, erule or
  2032 assumption failed.
  2033 
  2034 * Pure: Locale specifications now produce predicate definitions
  2035 according to the body of text (covering assumptions modulo local
  2036 definitions); predicate "loc_axioms" covers newly introduced text,
  2037 while "loc" is cumulative wrt. all included locale expressions; the
  2038 latter view is presented only on export into the global theory
  2039 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2040 on the old view without predicates;
  2041 
  2042 * Pure: predefined locales "var" and "struct" are useful for sharing
  2043 parameters (as in CASL, for example); just specify something like
  2044 ``var x + var y + struct M'' as import;
  2045 
  2046 * Pure: improved thms_containing: proper indexing of facts instead of
  2047 raw theorems; check validity of results wrt. current name space;
  2048 include local facts of proof configuration (also covers active
  2049 locales), cover fixed variables in index; may use "_" in term
  2050 specification; an optional limit for the number of printed facts may
  2051 be given (the default is 40);
  2052 
  2053 * Pure: disallow duplicate fact bindings within new-style theory files
  2054 (batch-mode only);
  2055 
  2056 * Provers: improved induct method: assumptions introduced by case
  2057 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2058 the goal statement); "foo" still refers to all facts collectively;
  2059 
  2060 * Provers: the function blast.overloaded has been removed: all constants
  2061 are regarded as potentially overloaded, which improves robustness in exchange
  2062 for slight decrease in efficiency;
  2063 
  2064 * Provers/linorder: New generic prover for transitivity reasoning over
  2065 linear orders.  Note: this prover is not efficient!
  2066 
  2067 * Isar: preview of problems to finish 'show' now produce an error
  2068 rather than just a warning (in interactive mode);
  2069 
  2070 
  2071 *** HOL ***
  2072 
  2073 * arith(_tac)
  2074 
  2075  - Produces a counter example if it cannot prove a goal.
  2076    Note that the counter example may be spurious if the goal is not a formula
  2077    of quantifier-free linear arithmetic.
  2078    In ProofGeneral the counter example appears in the trace buffer.
  2079 
  2080  - Knows about div k and mod k where k is a numeral of type nat or int.
  2081 
  2082  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2083    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2084    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2085 
  2086 * simp's arithmetic capabilities have been enhanced a bit: it now
  2087 takes ~= in premises into account (by performing a case split);
  2088 
  2089 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2090 are distributed over a sum of terms;
  2091 
  2092 * New tactic "trans_tac" and method "trans" instantiate
  2093 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2094 "<=", "<" and "=").
  2095 
  2096 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2097 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2098 
  2099 * 'typedef' command has new option "open" to suppress the set
  2100 definition;
  2101 
  2102 * functions Min and Max on finite sets have been introduced (theory
  2103 Finite_Set);
  2104 
  2105 * attribute [symmetric] now works for relations as well; it turns
  2106 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2107 
  2108 * induct over a !!-quantified statement (say !!x1..xn):
  2109   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2110 
  2111 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2112 %x. None. Warning: empty_def now refers to the previously hidden definition
  2113 of the empty set.
  2114 
  2115 * Algebra: formalization of classical algebra.  Intended as base for
  2116 any algebraic development in Isabelle.  Currently covers group theory
  2117 (up to Sylow's theorem) and ring theory (Universal Property of
  2118 Univariate Polynomials).  Contributions welcome;
  2119 
  2120 * GroupTheory: deleted, since its material has been moved to Algebra;
  2121 
  2122 * Complex: new directory of the complex numbers with numeric constants,
  2123 nonstandard complex numbers, and some complex analysis, standard and
  2124 nonstandard (Jacques Fleuriot);
  2125 
  2126 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2127 
  2128 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2129 Fleuriot);
  2130 
  2131 * Real/HahnBanach: updated and adapted to locales;
  2132 
  2133 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2134 Gray and Kramer);
  2135 
  2136 * UNITY: added the Meier-Sanders theory of progress sets;
  2137 
  2138 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2139 as abstract algorithms, instantiated to the JVM;
  2140 
  2141 * Bali: Java source language formalization. Type system, operational
  2142 semantics, axiomatic semantics. Supported language features:
  2143 classes, interfaces, objects,virtual methods, static methods,
  2144 static/instance fields, arrays, access modifiers, definite
  2145 assignment, exceptions.
  2146 
  2147 
  2148 *** ZF ***
  2149 
  2150 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2151 universe, etc.);
  2152 
  2153 * Main ZF: virtually all theories converted to new-style format;
  2154 
  2155 
  2156 *** ML ***
  2157 
  2158 * Pure: Tactic.prove provides sane interface for internal proofs;
  2159 omits the infamous "standard" operation, so this is more appropriate
  2160 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2161 
  2162 * Pure: improved error reporting of simprocs;
  2163 
  2164 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2165 up simprocs;
  2166 
  2167 
  2168 *** Document preparation ***
  2169 
  2170 * uses \par instead of \\ for line breaks in theory text. This may
  2171 shift some page breaks in large documents. To get the old behaviour
  2172 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2173 
  2174 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2175 other packages
  2176 
  2177 * \<euro> now needs package babel/greek instead of marvosym (which
  2178 broke \Rightarrow)
  2179 
  2180 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2181 textcomp package)
  2182 
  2183 
  2184 
  2185 New in Isabelle2002 (March 2002)
  2186 --------------------------------
  2187 
  2188 *** Document preparation ***
  2189 
  2190 * greatly simplified document preparation setup, including more
  2191 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2192 instructive isatool mkdir; users should basically be able to get
  2193 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2194 users may run a separate document processing stage manually like this:
  2195 "isatool usedir -D output HOL Test && isatool document Test/output";
  2196 
  2197 * theory dependency graph may now be incorporated into documents;
  2198 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2199 with \includegraphics of LaTeX;
  2200 
  2201 * proper spacing of consecutive markup elements, especially text
  2202 blocks after section headings;
  2203 
  2204 * support bold style (for single symbols only), input syntax is like
  2205 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2206 
  2207 * \<bullet> is now output as bold \cdot by default, which looks much
  2208 better in printed text;
  2209 
  2210 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2211 note that these symbols are currently unavailable in Proof General /
  2212 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2213 
  2214 * isatool latex no longer depends on changed TEXINPUTS, instead
  2215 isatool document copies the Isabelle style files to the target
  2216 location;
  2217 
  2218 
  2219 *** Isar ***
  2220 
  2221 * Pure/Provers: improved proof by cases and induction;
  2222   - 'case' command admits impromptu naming of parameters (such as
  2223     "case (Suc n)");
  2224   - 'induct' method divinates rule instantiation from the inductive
  2225     claim; no longer requires excessive ?P bindings for proper
  2226     instantiation of cases;
  2227   - 'induct' method properly enumerates all possibilities of set/type
  2228     rules; as a consequence facts may be also passed through *type*
  2229     rules without further ado;
  2230   - 'induct' method now derives symbolic cases from the *rulified*
  2231     rule (before it used to rulify cases stemming from the internal
  2232     atomized version); this means that the context of a non-atomic
  2233     statement becomes is included in the hypothesis, avoiding the
  2234     slightly cumbersome show "PROP ?case" form;
  2235   - 'induct' may now use elim-style induction rules without chaining
  2236     facts, using ``missing'' premises from the goal state; this allows
  2237     rules stemming from inductive sets to be applied in unstructured
  2238     scripts, while still benefitting from proper handling of non-atomic
  2239     statements; NB: major inductive premises need to be put first, all
  2240     the rest of the goal is passed through the induction;
  2241   - 'induct' proper support for mutual induction involving non-atomic
  2242     rule statements (uses the new concept of simultaneous goals, see
  2243     below);
  2244   - append all possible rule selections, but only use the first
  2245     success (no backtracking);
  2246   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2247   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2248   - added 'print_induct_rules' (covered by help item in recent Proof
  2249     General versions);
  2250   - moved induct/cases attributes to Pure, methods to Provers;
  2251   - generic method setup instantiated for FOL and HOL;
  2252 
  2253 * Pure: support multiple simultaneous goal statements, for example
  2254 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2255 meta-level mechanism, this acts as if several individual goals had
  2256 been stated separately; in particular common proof methods need to be
  2257 repeated in order to cover all claims; note that a single elimination
  2258 step is *not* sufficient to establish the two conjunctions, so this
  2259 fails:
  2260 
  2261   assume "A & B" then have A and B ..   (*".." fails*)
  2262 
  2263 better use "obtain" in situations as above; alternative refer to
  2264 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2265 
  2266 * Pure: proper integration with ``locales''; unlike the original
  2267 version by Florian Kammller, Isar locales package high-level proof
  2268 contexts rather than raw logical ones (e.g. we admit to include
  2269 attributes everywhere); operations on locales include merge and
  2270 rename; support for implicit arguments (``structures''); simultaneous
  2271 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2272 some examples;
  2273 
  2274 * Pure: the following commands have been ``localized'', supporting a
  2275 target locale specification "(in name)": 'lemma', 'theorem',
  2276 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2277 stored both within the locale and at the theory level (exported and
  2278 qualified by the locale name);
  2279 
  2280 * Pure: theory goals may now be specified in ``long'' form, with
  2281 ad-hoc contexts consisting of arbitrary locale elements. for example
  2282 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2283 definitions may be given, too); the result is a meta-level rule with
  2284 the context elements being discharged in the obvious way;
  2285 
  2286 * Pure: new proof command 'using' allows to augment currently used
  2287 facts after a goal statement ('using' is syntactically analogous to
  2288 'apply', but acts on the goal's facts only); this allows chained facts
  2289 to be separated into parts given before and after a claim, as in
  2290 ``from a and b have C using d and e <proof>'';
  2291 
  2292 * Pure: renamed "antecedent" case to "rule_context";
  2293 
  2294 * Pure: new 'judgment' command records explicit information about the
  2295 object-logic embedding (used by several tools internally); no longer
  2296 use hard-wired "Trueprop";
  2297 
  2298 * Pure: added 'corollary' command;
  2299 
  2300 * Pure: fixed 'token_translation' command;
  2301 
  2302 * Pure: removed obsolete 'exported' attribute;
  2303 
  2304 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2305 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2306 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2307 
  2308 * Pure: method 'atomize' presents local goal premises as object-level
  2309 statements (atomic meta-level propositions); setup controlled via
  2310 rewrite rules declarations of 'atomize' attribute; example
  2311 application: 'induct' method with proper rule statements in improper
  2312 proof *scripts*;
  2313 
  2314 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2315 now consider the syntactic context of assumptions, giving a better
  2316 chance to get type-inference of the arguments right (this is
  2317 especially important for locales);
  2318 
  2319 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2320 mode;
  2321 
  2322 * Pure/obtain: the formal conclusion "thesis", being marked as
  2323 ``internal'', may no longer be reference directly in the text;
  2324 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2325 situations;
  2326 
  2327 * Pure: generic 'sym' attribute which declares a rule both as pure
  2328 'elim?' and for the 'symmetric' operation;
  2329 
  2330 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2331 text; the fixed correlation with particular command syntax has been
  2332 discontinued;
  2333 
  2334 * Pure: new method 'rules' is particularly well-suited for proof
  2335 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2336 but often produces more compact proof terms with less detours;
  2337 
  2338 * Pure/Provers/classical: simplified integration with pure rule
  2339 attributes and methods; the classical "intro?/elim?/dest?"
  2340 declarations coincide with the pure ones; the "rule" method no longer
  2341 includes classically swapped intros; "intro" and "elim" methods no
  2342 longer pick rules from the context; also got rid of ML declarations
  2343 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2344 INCOMPATIBILITY;
  2345 
  2346 * Provers/classical: attribute 'swapped' produces classical inversions
  2347 of introduction rules;
  2348 
  2349 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2350 rules instead of full simplifier context; 'iff' attribute handles
  2351 conditional rules;
  2352 
  2353 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2354 
  2355 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2356 "(permissive)" option to recover old behavior;
  2357 
  2358 * HOL: 'inductive' no longer features separate (collective) attributes
  2359 for 'intros' (was found too confusing);
  2360 
  2361 * HOL: properly declared induction rules less_induct and
  2362 wf_induct_rule;
  2363 
  2364 
  2365 *** HOL ***
  2366 
  2367 * HOL: moved over to sane numeral syntax; the new policy is as
  2368 follows:
  2369 
  2370   - 0 and 1 are polymorphic constants, which are defined on any
  2371   numeric type (nat, int, real etc.);
  2372 
  2373   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2374   binary representation internally;
  2375 
  2376   - type nat has special constructor Suc, and generally prefers Suc 0
  2377   over 1::nat and Suc (Suc 0) over 2::nat;
  2378 
  2379 This change may cause significant problems of INCOMPATIBILITY; here
  2380 are some hints on converting existing sources:
  2381 
  2382   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2383   entities, so expressions involving "-" (unary or binary minus) need
  2384   to be spaced properly;
  2385 
  2386   - existing occurrences of "1" may need to be constraint "1::nat" or
  2387   even replaced by Suc 0; similar for old "2";
  2388 
  2389   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2390 
  2391   - remove all special provisions on numerals in proofs;
  2392 
  2393 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2394 representation (depends on bin_arith_simps in the default context);
  2395 
  2396 * HOL: symbolic syntax for x^2 (numeral 2);
  2397 
  2398 * HOL: the class of all HOL types is now called "type" rather than
  2399 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2400 in axclass/classes, instance/arities, and (usually rare) occurrences
  2401 in typings (of consts etc.); internally the class is called
  2402 "HOL.type", ML programs should refer to HOLogic.typeS;
  2403 
  2404 * HOL/record package improvements:
  2405   - new derived operations "fields" to build a partial record section,
  2406     "extend" to promote a fixed record to a record scheme, and
  2407     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2408     declared as simp by default;
  2409   - shared operations ("more", "fields", etc.) now need to be always
  2410     qualified) --- potential INCOMPATIBILITY;
  2411   - removed "make_scheme" operations (use "make" with "extend") --
  2412     INCOMPATIBILITY;
  2413   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2414   - provides cases/induct rules for use with corresponding Isar
  2415     methods (for concrete records, record schemes, concrete more
  2416     parts, and schematic more parts -- in that order);
  2417   - internal definitions directly based on a light-weight abstract
  2418     theory of product types over typedef rather than datatype;
  2419 
  2420 * HOL: generic code generator for generating executable ML code from
  2421 specifications; specific support for HOL constructs such as inductive
  2422 datatypes and sets, as well as recursive functions; can be invoked
  2423 via 'generate_code' theory section;
  2424 
  2425 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2426 
  2427 * HOL: consolidated and renamed several theories.  In particular:
  2428         Ord.thy has been absorbed into HOL.thy
  2429         String.thy has been absorbed into List.thy
  2430 
  2431 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2432 (beware of argument permutation!);
  2433 
  2434 * HOL: linorder_less_split superseded by linorder_cases;
  2435 
  2436 * HOL/List: "nodups" renamed to "distinct";
  2437 
  2438 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2439 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2440   - Ex_def has changed, now need to use some_eq_ex
  2441 
  2442 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2443 in this (rare) case use:
  2444 
  2445   delSWrapper "split_all_tac"
  2446   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2447 
  2448 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2449 MAY FAIL;
  2450 
  2451 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2452 Isabelle's type classes, ^ on functions and relations has too general
  2453 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2454 necessary to attach explicit type constraints;
  2455 
  2456 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2457 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2458 renamed accordingly (eg "compI" -> "rel_compI").
  2459 
  2460 * HOL: syntax translations now work properly with numerals and records
  2461 expressions;
  2462 
  2463 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2464 of "lam" -- INCOMPATIBILITY;
  2465 
  2466 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2467 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2468 renamed "Product_Type.unit";
  2469 
  2470 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2471 
  2472 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2473 the "cases" method);
  2474 
  2475 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2476 Florian Kammller);
  2477 
  2478 * HOL/IMP: updated and converted to new-style theory format; several
  2479 parts turned into readable document, with proper Isar proof texts and
  2480 some explanations (by Gerwin Klein);
  2481 
  2482 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2483 
  2484 * HOL-Hyperreal is now a logic image;
  2485 
  2486 
  2487 *** HOLCF ***
  2488 
  2489 * Isar: consts/constdefs supports mixfix syntax for continuous
  2490 operations;
  2491 
  2492 * Isar: domain package adapted to new-style theory format, e.g. see
  2493 HOLCF/ex/Dnat.thy;
  2494 
  2495 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2496 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2497 lift.induct_tac, always use UU instead of Undef;
  2498 
  2499 * HOLCF/IMP: updated and converted to new-style theory;
  2500 
  2501 
  2502 *** ZF ***
  2503 
  2504 * Isar: proper integration of logic-specific tools and packages,
  2505 including theory commands '(co)inductive', '(co)datatype',
  2506 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2507 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2508 
  2509 * theory Main no longer includes AC; for the Axiom of Choice, base
  2510 your theory on Main_ZFC;
  2511 
  2512 * the integer library now covers quotients and remainders, with many
  2513 laws relating division to addition, multiplication, etc.;
  2514 
  2515 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2516 typeless version of the formalism;
  2517 
  2518 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2519 format;
  2520 
  2521 * ZF/Induct: new directory for examples of inductive definitions,
  2522 including theory Multiset for multiset orderings; converted to
  2523 new-style theory format;
  2524 
  2525 * ZF: many new theorems about lists, ordinals, etc.;
  2526 
  2527 
  2528 *** General ***
  2529 
  2530 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2531 variable proof controls level of detail: 0 = no proofs (only oracle
  2532 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2533 also ref manual for further ML interfaces;
  2534 
  2535 * Pure/axclass: removed obsolete ML interface
  2536 goal_subclass/goal_arity;
  2537 
  2538 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2539 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2540 separate tokens, so expressions involving minus need to be spaced
  2541 properly;
  2542 
  2543 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2544 rather than "infixl" or "infixr";
  2545 
  2546 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2547 sort constraint specifications in type inference; e.g. "x::_::foo"
  2548 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2549 type variable);
  2550 
  2551 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2552 control output of nested => (types); the default behavior is
  2553 "type_brackets";
  2554 
  2555 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2556 tokens into AST constants;
  2557 
  2558 * Pure/syntax: prefer later declarations of translations and print
  2559 translation functions; potential INCOMPATIBILITY: need to reverse
  2560 multiple declarations for same syntax element constant;
  2561 
  2562 * Pure/show_hyps reset by default (in accordance to existing Isar
  2563 practice);
  2564 
  2565 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2566 addSafter;
  2567 
  2568 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2569 as well;
  2570 
  2571 * system: tested support for MacOS X; should be able to get Isabelle +
  2572 Proof General to work in a plain Terminal after installing Poly/ML
  2573 (e.g. from the Isabelle distribution area) and GNU bash alone
  2574 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2575 support requires further installations, e.g. from
  2576 http://fink.sourceforge.net/);
  2577 
  2578 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2579 
  2580 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2581 of 40 MB), cf. ML_OPTIONS;
  2582 
  2583 * system: Proof General keywords specification is now part of the
  2584 Isabelle distribution (see etc/isar-keywords.el);
  2585 
  2586 * system: support for persistent Proof General sessions (refrain from
  2587 outdating all loaded theories on startup); user may create writable
  2588 logic images like this: ``isabelle -q HOL Test'';
  2589 
  2590 * system: smart selection of Isabelle process versus Isabelle
  2591 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2592 run both "isabelle" and "Isabelle" even if file names are badly
  2593 damaged (executable inspects the case of the first letter of its own
  2594 name); added separate "isabelle-process" and "isabelle-interface";
  2595 
  2596 * system: refrain from any attempt at filtering input streams; no
  2597 longer support ``8bit'' encoding of old isabelle font, instead proper
  2598 iso-latin characters may now be used; the related isatools
  2599 "symbolinput" and "nonascii" have disappeared as well;
  2600 
  2601 * system: removed old "xterm" interface (the print modes "xterm" and
  2602 "xterm_color" are still available for direct use in a suitable
  2603 terminal);
  2604 
  2605 
  2606 
  2607 New in Isabelle99-2 (February 2001)
  2608 -----------------------------------
  2609 
  2610 *** Overview of INCOMPATIBILITIES ***
  2611 
  2612 * HOL: please note that theories in the Library and elsewhere often use the
  2613 new-style (Isar) format; to refer to their theorems in an ML script you must
  2614 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2615 
  2616 * HOL: inductive package no longer splits induction rule aggressively,
  2617 but only as far as specified by the introductions given; the old
  2618 format may be recovered via ML function complete_split_rule or attribute
  2619 'split_rule (complete)';
  2620 
  2621 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2622 gfp_Tarski to gfp_unfold;
  2623 
  2624 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2625 
  2626 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2627 relation); infix "^^" has been renamed "``"; infix "``" has been
  2628 renamed "`"; "univalent" has been renamed "single_valued";
  2629 
  2630 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2631 operation;
  2632 
  2633 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2634 
  2635 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2636 
  2637 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2638 consequence, it is no longer monotonic wrt. the local goal context
  2639 (which is now passed through the inductive cases);
  2640 
  2641 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2642 \<gg> to \<ggreater>;
  2643 
  2644 
  2645 *** Document preparation ***
  2646 
  2647 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2648 available: are "it" for near math-mode best-style output, "sl" for
  2649 slanted text style, and "tt" for plain type-writer; if no
  2650 \isabellestyle command is given, output is according to slanted
  2651 type-writer);
  2652 
  2653 * support sub/super scripts (for single symbols only), input syntax is
  2654 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2655 
  2656 * some more standard symbols; see Appendix A of the system manual for
  2657 the complete list of symbols defined in isabellesym.sty;
  2658 
  2659 * improved isabelle style files; more abstract symbol implementation
  2660 (should now use \isamath{...} and \isatext{...} in custom symbol
  2661 definitions);
  2662 
  2663 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2664 state; Note that presentation of goal states does not conform to
  2665 actual human-readable proof documents.  Please do not include goal
  2666 states into document output unless you really know what you are doing!
  2667 
  2668 * proper indentation of antiquoted output with proportional LaTeX
  2669 fonts;
  2670 
  2671 * no_document ML operator temporarily disables LaTeX document
  2672 generation;
  2673 
  2674 * isatool unsymbolize tunes sources for plain ASCII communication;
  2675 
  2676 
  2677 *** Isar ***
  2678 
  2679 * Pure: Isar now suffers initial goal statements to contain unbound
  2680 schematic variables (this does not conform to actual readable proof
  2681 documents, due to unpredictable outcome and non-compositional proof
  2682 checking); users who know what they are doing may use schematic goals
  2683 for Prolog-style synthesis of proven results;
  2684 
  2685 * Pure: assumption method (an implicit finishing) now handles actual
  2686 rules as well;
  2687 
  2688 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2689 initial goal, declare "that" only as Pure intro (only for single
  2690 steps); the "that" rule assumption may now be involved in implicit
  2691 finishing, thus ".." becomes a feasible for trivial obtains;
  2692 
  2693 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2694 instance proofs may be performed by "..";
  2695 
  2696 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2697 statements as well;
  2698 
  2699 * Pure: more robust selection of calculational rules;
  2700 
  2701 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2702 rule (as well as the assumption rule);
  2703 
  2704 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2705 lemmas, using the graph browser tool;
  2706 
  2707 * Pure: predict failure of "show" in interactive mode;
  2708 
  2709 * Pure: 'thms_containing' now takes actual terms as arguments;
  2710 
  2711 * HOL: improved method 'induct' --- now handles non-atomic goals
  2712 (potential INCOMPATIBILITY); tuned error handling;
  2713 
  2714 * HOL: cases and induct rules now provide explicit hints about the
  2715 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2716 any remaining facts are inserted into the goal verbatim;
  2717 
  2718 * HOL: local contexts (aka cases) may now contain term bindings as
  2719 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2720 the result to be shown in each case;
  2721 
  2722 * HOL: added 'recdef_tc' command;
  2723 
  2724 * isatool convert assists in eliminating legacy ML scripts;
  2725 
  2726 
  2727 *** HOL ***
  2728 
  2729 * HOL/Library: a collection of generic theories to be used together
  2730 with main HOL; the theory loader path already includes this directory
  2731 by default; the following existing theories have been moved here:
  2732 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2733 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2734 
  2735 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2736 modelling and verification task performed in Isabelle/HOL +
  2737 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2738 
  2739 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2740 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2741 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2742 'domain', this makes the theory consistent with mathematical
  2743 literature;
  2744 
  2745 * HOL basics: added overloaded operations "inverse" and "divide"
  2746 (infix "/"), syntax for generic "abs" operation, generic summation
  2747 operator \<Sum>;
  2748 
  2749 * HOL/typedef: simplified package, provide more useful rules (see also
  2750 HOL/subset.thy);
  2751 
  2752 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2753 now expressed as a proper nested rule (old-style tactic scripts may
  2754 require atomize_strip_tac to cope with non-atomic premises);
  2755 
  2756 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2757 to "split_conv" (old name still available for compatibility);
  2758 
  2759 * HOL: improved concrete syntax for strings (e.g. allows translation
  2760 rules with string literals);
  2761 
  2762 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2763  and Fleuriot's mechanization of analysis, including the transcendental
  2764  functions for the reals;
  2765 
  2766 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2767 
  2768 
  2769 *** CTT ***
  2770 
  2771 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2772 "lam" is displayed as TWO lambda-symbols
  2773 
  2774 * CTT: theory Main now available, containing everything (that is, Bool
  2775 and Arith);
  2776 
  2777 
  2778 *** General ***
  2779 
  2780 * Pure: the Simplifier has been implemented properly as a derived rule
  2781 outside of the actual kernel (at last!); the overall performance
  2782 penalty in practical applications is about 50%, while reliability of
  2783 the Isabelle inference kernel has been greatly improved;
  2784 
  2785 * print modes "brackets" and "no_brackets" control output of nested =>
  2786 (types) and ==> (props); the default behaviour is "brackets";
  2787 
  2788 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2789 as assumptions as well;
  2790 
  2791 * system: support Poly/ML 4.0;
  2792 
  2793 * system: isatool install handles KDE version 1 or 2;
  2794 
  2795 
  2796 
  2797 New in Isabelle99-1 (October 2000)
  2798 ----------------------------------
  2799 
  2800 *** Overview of INCOMPATIBILITIES ***
  2801 
  2802 * HOL: simplification of natural numbers is much changed; to partly
  2803 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2804 issue the following ML commands:
  2805 
  2806   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2807   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2808 
  2809 * HOL: simplification no longer dives into case-expressions; this is
  2810 controlled by "t.weak_case_cong" for each datatype t;
  2811 
  2812 * HOL: nat_less_induct renamed to less_induct;
  2813 
  2814 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2815 fixsome to patch .thy and .ML sources automatically;
  2816 
  2817   select_equality  -> some_equality
  2818   select_eq_Ex     -> some_eq_ex
  2819   selectI2EX       -> someI2_ex
  2820   selectI2         -> someI2
  2821   selectI          -> someI
  2822   select1_equality -> some1_equality
  2823   Eps_sym_eq       -> some_sym_eq_trivial
  2824   Eps_eq           -> some_eq_trivial
  2825 
  2826 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2827 
  2828 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2829 instead);
  2830 
  2831 * HOL: the recursion equations generated by 'recdef' are now called
  2832 f.simps instead of f.rules;
  2833 
  2834 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2835 
  2836 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2837 sometimes be needed;
  2838 
  2839 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2840 
  2841 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2842 
  2843 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2844 product is now "<*>" instead of "Times"; the lexicographic product is
  2845 now "<*lex*>" instead of "**";
  2846 
  2847 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2848 of main HOL, but was unused); better use HOL's datatype package;
  2849 
  2850 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2851 the old syntax may be recovered as follows:
  2852 
  2853   syntax (symbols)
  2854     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2855       (infixl "\\<oplus>" 100)
  2856 
  2857 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2858 
  2859 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2860 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2861 internally;
  2862 
  2863 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2864 changed from A/r to A//r;
  2865 
  2866 * ZF: new treatment of arithmetic (nat & int) may break some old
  2867 proofs;
  2868 
  2869 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2870 rulify -> rule_format, elimify -> elim_format, ...);
  2871 
  2872 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2873 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2874 should have to change intro!! to intro? only); replaced "delrule" by
  2875 "rule del";
  2876 
  2877 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2878 
  2879 * Provers: strengthened force_tac by using new first_best_tac;
  2880 
  2881 * LaTeX document preparation: several changes of isabelle.sty (see
  2882 lib/texinputs);
  2883 
  2884 
  2885 *** Document preparation ***
  2886 
  2887 * formal comments (text blocks etc.) in new-style theories may now
  2888 contain antiquotations of thm/prop/term/typ/text to be presented
  2889 according to latex print mode; concrete syntax is like this:
  2890 @{term[show_types] "f(x) = a + x"};
  2891 
  2892 * isatool mkdir provides easy setup of Isabelle session directories,
  2893 including proper document sources;
  2894 
  2895 * generated LaTeX sources are now deleted after successful run
  2896 (isatool document -c); may retain a copy somewhere else via -D option
  2897 of isatool usedir;
  2898 
  2899 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2900 style files, achieving self-contained LaTeX sources and simplifying
  2901 LaTeX debugging;
  2902 
  2903 * old-style theories now produce (crude) LaTeX output as well;
  2904 
  2905 * browser info session directories are now self-contained (may be put
  2906 on WWW server seperately); improved graphs of nested sessions; removed
  2907 graph for 'all sessions';
  2908 
  2909 * several improvements in isabelle style files; \isabellestyle{it}
  2910 produces fake math mode output; \isamarkupheader is now \section by
  2911 default; see lib/texinputs/isabelle.sty etc.;
  2912 
  2913 
  2914 *** Isar ***
  2915 
  2916 * Isar/Pure: local results and corresponding term bindings are now
  2917 subject to Hindley-Milner polymorphism (similar to ML); this
  2918 accommodates incremental type-inference very nicely;
  2919 
  2920 * Isar/Pure: new derived language element 'obtain' supports
  2921 generalized existence reasoning;
  2922 
  2923 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2924 support accumulation of results, without applying any rules yet;
  2925 useful to collect intermediate results without explicit name
  2926 references, and for use with transitivity rules with more than 2
  2927 premises;
  2928 
  2929 * Isar/Pure: scalable support for case-analysis type proofs: new
  2930 'case' language element refers to local contexts symbolically, as
  2931 produced by certain proof methods; internally, case names are attached
  2932 to theorems as "tags";
  2933 
  2934 * Isar/Pure: theory command 'hide' removes declarations from
  2935 class/type/const name spaces;
  2936 
  2937 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2938 indicate potential overloading;
  2939 
  2940 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2941 
  2942 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2943 "{a,b,c}" instead of {a,b,c};
  2944 
  2945 * Isar/Pure now provides its own version of intro/elim/dest
  2946 attributes; useful for building new logics, but beware of confusion
  2947 with the version in Provers/classical;
  2948 
  2949 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2950 case name 'antecedent';
  2951 
  2952 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2953 to the current context is now done automatically);
  2954 
  2955 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2956 for definining proof methods in ML;
  2957 
  2958 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2959 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2960 most cases, one should have to change intro!! to intro? only);
  2961 replaced "delrule" by "rule del";
  2962 
  2963 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2964 'symmetric' attribute (the latter supercedes [RS sym]);
  2965 
  2966 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2967 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2968 well (including splits);
  2969 
  2970 * Isar/Provers: Simplifier and Classical methods now support all kind
  2971 of modifiers used in the past, including 'cong', 'iff', etc.
  2972 
  2973 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  2974 of Simplifier and Classical reasoner);
  2975 
  2976 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  2977 now support named cases; major packages (inductive, datatype, primrec,
  2978 recdef) support case names and properly name parameters;
  2979 
  2980 * Isar/HOL: new transitivity rules for substitution in inequalities --
  2981 monotonicity conditions are extracted to be proven at end of
  2982 calculations;
  2983 
  2984 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  2985 method anyway;
  2986 
  2987 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  2988 split_if split_if_asm; datatype package provides theorems foo.splits =
  2989 foo.split foo.split_asm for each datatype;
  2990 
  2991 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  2992 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  2993 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  2994 use "(cases (simplified))" method in proper proof texts);
  2995 
  2996 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  2997 
  2998 * Isar: names of theorems etc. may be natural numbers as well;
  2999 
  3000 * Isar: 'pr' command: optional arguments for goals_limit and
  3001 ProofContext.prems_limit; no longer prints theory contexts, but only
  3002 proof states;
  3003 
  3004 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3005 additional print modes to be specified; e.g. "pr(latex)" will print
  3006 proof state according to the Isabelle LaTeX style;
  3007 
  3008 * Isar: improved support for emulating tactic scripts, including proof
  3009 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3010 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3011 (for HOL datatypes);
  3012 
  3013 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3014 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3015 'proof method scripts' have to be in depth-first order;
  3016 
  3017 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3018 
  3019 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3020 should instead use individual commands for printing items
  3021 (print_commands, print_methods etc.);
  3022 
  3023 * Isar: added 'nothing' --- the empty list of theorems;
  3024 
  3025 
  3026 *** HOL ***
  3027 
  3028 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3029 corresponding virtual machine and a specification of its bytecode
  3030 verifier and a lightweight bytecode verifier, including proofs of
  3031 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3032 Cornelia Pusch (see also the homepage of project Bali at
  3033 http://isabelle.in.tum.de/Bali/);
  3034 
  3035 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3036 Clemens Ballarin;
  3037 
  3038 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3039 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3040 Rasmussen;
  3041 
  3042 * HOL/Lattice: fundamental concepts of lattice theory and order
  3043 structures, including duals, properties of bounds versus algebraic
  3044 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3045 Theorem for complete lattices etc.; may also serve as a demonstration
  3046 for abstract algebraic reasoning using axiomatic type classes, and
  3047 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3048 
  3049 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3050 von Oheimb;
  3051 
  3052 * HOL/IMPP: extension of IMP with local variables and mutually
  3053 recursive procedures, by David von Oheimb;
  3054 
  3055 * HOL/Lambda: converted into new-style theory and document;
  3056 
  3057 * HOL/ex/Multiquote: example of multiple nested quotations and
  3058 anti-quotations -- basically a generalized version of de-Bruijn
  3059 representation; very useful in avoiding lifting of operations;
  3060 
  3061 * HOL/record: added general record equality rule to simpset; fixed
  3062 select-update simplification procedure to handle extended records as
  3063 well; admit "r" as field name;
  3064 
  3065 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3066 other numeric types and also as the identity of groups, rings, etc.;
  3067 
  3068 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3069 Types nat and int belong to this axclass;
  3070 
  3071 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3072    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3073    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3074   two terms #m*u and #n*u are replaced by #(m+n)*u
  3075     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3076   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3077     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3078 
  3079 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3080 powerful prover for predicate logic but knows nothing of clasets; see
  3081 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3082 
  3083 * HOL: new version of "case_tac" subsumes both boolean case split and
  3084 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3085 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3086 
  3087 * HOL: simplification no longer dives into case-expressions: only the
  3088 selector expression is simplified, but not the remaining arms; to
  3089 enable full simplification of case-expressions for datatype t, you may
  3090 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3091 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3092 
  3093 * HOL/recdef: the recursion equations generated by 'recdef' for
  3094 function 'f' are now called f.simps instead of f.rules; if all
  3095 termination conditions are proved automatically, these simplification
  3096 rules are added to the simpset, as in primrec; rules may be named
  3097 individually as well, resulting in a separate list of theorems for
  3098 each equation;
  3099 
  3100 * HOL/While is a new theory that provides a while-combinator. It
  3101 permits the definition of tail-recursive functions without the
  3102 provision of a termination measure. The latter is necessary once the
  3103 invariant proof rule for while is applied.
  3104 
  3105 * HOL: new (overloaded) notation for the set of elements below/above
  3106 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3107 
  3108 * HOL: theorems impI, allI, ballI bound as "strip";
  3109 
  3110 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3111 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3112 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3113 
  3114 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3115 
  3116 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3117 main HOL, but was unused);
  3118 
  3119 * HOL: fewer consts declared as global (e.g. have to refer to
  3120 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3121 
  3122 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3123 in case of overlap with user translations (e.g. judgements over
  3124 tuples); (note that the underlying logical represenation is still
  3125 bogus);
  3126 
  3127 
  3128 *** ZF ***
  3129 
  3130 * ZF: simplification automatically cancels common terms in arithmetic
  3131 expressions over nat and int;
  3132 
  3133 * ZF: new treatment of nat to minimize type-checking: all operators
  3134 coerce their operands to a natural number using the function natify,
  3135 making the algebraic laws unconditional;
  3136 
  3137 * ZF: as above, for int: operators coerce their operands to an integer
  3138 using the function intify;
  3139 
  3140 * ZF: the integer library now contains many of the usual laws for the
  3141 orderings, including $<=, and monotonicity laws for $+ and $*;
  3142 
  3143 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3144 simplification;
  3145 
  3146 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3147 to the simplifier and classical reasoner simultaneously;
  3148 
  3149 
  3150 *** General ***
  3151 
  3152 * Provers: blast_tac now handles actual object-logic rules as
  3153 assumptions; note that auto_tac uses blast_tac internally as well;
  3154 
  3155 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3156 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3157 
  3158 * Provers: delrules now handles destruct rules as well (no longer need
  3159 explicit make_elim);
  3160 
  3161 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3162   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3163 use instead the strong form,
  3164   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3165 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3166 from destruct-rules;
  3167 
  3168 * Provers: Simplifier.easy_setup provides a fast path to basic
  3169 Simplifier setup for new object-logics;
  3170 
  3171 * Pure: AST translation rules no longer require constant head on LHS;
  3172 
  3173 * Pure: improved name spaces: ambiguous output is qualified; support
  3174 for hiding of names;
  3175 
  3176 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3177 XSYMBOL_HOME; no longer need to do manual configuration in most
  3178 situations;
  3179 
  3180 * system: compression of ML heaps images may now be controlled via -c
  3181 option of isabelle and isatool usedir (currently only observed by
  3182 Poly/ML);
  3183 
  3184 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3185 useful for remote X11);
  3186 
  3187 * system: provide TAGS file for Isabelle sources;
  3188 
  3189 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3190 order;
  3191 
  3192 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3193 timing flag supersedes proof_timing and Toplevel.trace;
  3194 
  3195 * ML: new combinators |>> and |>>> for incremental transformations
  3196 with secondary results (e.g. certain theory extensions):
  3197 
  3198 * ML: PureThy.add_defs gets additional argument to indicate potential
  3199 overloading (usually false);
  3200 
  3201 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3202 results;
  3203 
  3204 
  3205 
  3206 New in Isabelle99 (October 1999)
  3207 --------------------------------
  3208 
  3209 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3210 
  3211 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3212 are no longer simplified.  (This allows the simplifier to unfold recursive
  3213 functional programs.)  To restore the old behaviour, declare
  3214 
  3215     Delcongs [if_weak_cong];
  3216 
  3217 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3218 complement;
  3219 
  3220 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3221 
  3222 * HOL/datatype: mutual_induct_tac no longer exists --
  3223   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3224 
  3225 * HOL/typedef: fixed type inference for representing set; type
  3226 arguments now have to occur explicitly on the rhs as type constraints;
  3227 
  3228 * ZF: The con_defs part of an inductive definition may no longer refer
  3229 to constants declared in the same theory;
  3230 
  3231 * HOL, ZF: the function mk_cases, generated by the inductive
  3232 definition package, has lost an argument.  To simplify its result, it
  3233 uses the default simpset instead of a supplied list of theorems.
  3234 
  3235 * HOL/List: the constructors of type list are now Nil and Cons;
  3236 
  3237 * Simplifier: the type of the infix ML functions
  3238         setSSolver addSSolver setSolver addSolver
  3239 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3240 for packaging solvers. A solver is created via
  3241         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3242 where the string argument is only a comment.
  3243 
  3244 
  3245 *** Proof tools ***
  3246 
  3247 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3248 decision procedure for linear arithmetic. Currently it is used for
  3249 types `nat', `int', and `real' in HOL (see below); it can, should and
  3250 will be instantiated for other types and logics as well.
  3251 
  3252 * The simplifier now accepts rewrite rules with flexible heads, eg
  3253      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3254   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3255   matching.
  3256 
  3257 
  3258 *** General ***
  3259 
  3260 * New Isabelle/Isar subsystem provides an alternative to traditional
  3261 tactical theorem proving; together with the ProofGeneral/isar user
  3262 interface it offers an interactive environment for developing human
  3263 readable proof documents (Isar == Intelligible semi-automated
  3264 reasoning); for further information see isatool doc isar-ref,
  3265 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3266 
  3267 * improved and simplified presentation of theories: better HTML markup
  3268 (including colors), graph views in several sizes; isatool usedir now
  3269 provides a proper interface for user theories (via -P option); actual
  3270 document preparation based on (PDF)LaTeX is available as well (for
  3271 new-style theories only); see isatool doc system for more information;
  3272 
  3273 * native support for Proof General, both for classic Isabelle and
  3274 Isabelle/Isar;
  3275 
  3276 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3277 using the graph browser tool;
  3278 
  3279 * Isabelle manuals now also available as PDF;
  3280 
  3281 * theory loader rewritten from scratch (may not be fully
  3282 bug-compatible); old loadpath variable has been replaced by show_path,
  3283 add_path, del_path, reset_path functions; new operations such as
  3284 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3285 isatool doc ref);
  3286 
  3287 * improved isatool install: option -k creates KDE application icon,
  3288 option -p DIR installs standalone binaries;
  3289 
  3290 * added ML_PLATFORM setting (useful for cross-platform installations);
  3291 more robust handling of platform specific ML images for SML/NJ;
  3292 
  3293 * the settings environment is now statically scoped, i.e. it is never
  3294 created again in sub-processes invoked from isabelle, isatool, or
  3295 Isabelle;
  3296 
  3297 * path element specification '~~' refers to '$ISABELLE_HOME';
  3298 
  3299 * in locales, the "assumes" and "defines" parts may be omitted if
  3300 empty;
  3301 
  3302 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3303 long arrows);
  3304 
  3305 * new print_mode "HTML";
  3306 
  3307 * new flag show_tags controls display of tags of theorems (which are
  3308 basically just comments that may be attached by some tools);
  3309 
  3310 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3311 mode and goal output format:
  3312 
  3313 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3314 244c244
  3315 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3316 ---
  3317 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3318 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3319 181c181
  3320 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3321 ---
  3322 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3323 
  3324 * function bind_thms stores lists of theorems (cf. bind_thm);
  3325 
  3326 * new shorthand tactics ftac, eatac, datac, fatac;
  3327 
  3328 * qed (and friends) now accept "" as result name; in that case the
  3329 theorem is not stored, but proper checks and presentation of the
  3330 result still apply;
  3331 
  3332 * theorem database now also indexes constants "Trueprop", "all",
  3333 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3334 
  3335 
  3336 *** HOL ***
  3337 
  3338 ** HOL arithmetic **
  3339 
  3340 * There are now decision procedures for linear arithmetic over nat and
  3341 int:
  3342 
  3343 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3344 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3345 are treated as atomic; subformulae not involving type `nat' or `int'
  3346 are ignored; quantified subformulae are ignored unless they are
  3347 positive universal or negative existential. The tactic has to be
  3348 invoked by hand and can be a little bit slow. In particular, the
  3349 running time is exponential in the number of occurrences of `min' and
  3350 `max', and `-' on `nat'.
  3351 
  3352 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3353 (negated) (in)equalities among the premises and the conclusion into
  3354 account (i.e. no compound formulae) and does not know about `min' and
  3355 `max', and `-' on `nat'. It is fast and is used automatically by the
  3356 simplifier.
  3357 
  3358 NB: At the moment, these decision procedures do not cope with mixed
  3359 nat/int formulae where the two parts interact, such as `m < n ==>
  3360 int(m) < int(n)'.
  3361 
  3362 * HOL/Numeral provides a generic theory of numerals (encoded
  3363 efficiently as bit strings); setup for types nat/int/real is in place;
  3364 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3365 int, existing theories and proof scripts may require a few additional
  3366 type constraints;
  3367 
  3368 * integer division and remainder can now be performed on constant
  3369 arguments;
  3370 
  3371 * many properties of integer multiplication, division and remainder
  3372 are now available;
  3373 
  3374 * An interface to the Stanford Validity Checker (SVC) is available through the
  3375 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3376 are proved automatically.  SVC must be installed separately, and its results
  3377 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3378 invocation of the underlying oracle).  For SVC see
  3379   http://verify.stanford.edu/SVC
  3380 
  3381 * IsaMakefile: the HOL-Real target now builds an actual image;
  3382 
  3383 
  3384 ** HOL misc **
  3385 
  3386 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3387 (in Isabelle/Isar) -- by Gertrud Bauer;
  3388 
  3389 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3390 analysis for assembly languages with subtypes;
  3391 
  3392 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3393 -- avoids syntactic ambiguities and treats state, transition, and
  3394 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3395 changed syntax and (many) tactics;
  3396 
  3397 * HOL/inductive: Now also handles more general introduction rules such
  3398   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3399   theorems are now maintained within the theory (maintained via the
  3400   "mono" attribute);
  3401 
  3402 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3403   (using function types) such as
  3404 
  3405   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3406 
  3407 * HOL/record: record_simproc (part of the default simpset) takes care
  3408 of selectors applied to updated records; record_split_tac is no longer
  3409 part of the default claset; update_defs may now be removed from the
  3410 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3411 
  3412   claset_ref () := claset() addSWrapper record_split_wrapper;
  3413   Delsimprocs [record_simproc]
  3414 
  3415 * HOL/typedef: fixed type inference for representing set; type
  3416 arguments now have to occur explicitly on the rhs as type constraints;
  3417 
  3418 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3419 names rather than an ML expression;
  3420 
  3421 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3422 supplied later.  Program schemes can be defined, such as
  3423     "While B C s = (if B s then While B C (C s) else s)"
  3424 where the well-founded relation can be chosen after B and C have been given.
  3425 
  3426 * HOL/List: the constructors of type list are now Nil and Cons;
  3427 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3428 course, ML tools referring to List.list.op # etc. have to be adapted;
  3429 
  3430 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3431 disabled by default; run isabelle with option -m HOL to get back to
  3432 the original Gordon/HOL-style output;
  3433 
  3434 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3435 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3436 
  3437 * HOL basic syntax simplified (more orthogonal): all variants of
  3438 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3439 Eps operator is provided as well: "SOME x. P[x]";
  3440 
  3441 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3442 
  3443 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3444 thus available for user theories;
  3445 
  3446 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3447 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3448 time;
  3449 
  3450 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3451 several times and then mp;
  3452 
  3453 
  3454 *** LK ***
  3455 
  3456 * the notation <<...>> is now available as a notation for sequences of
  3457 formulas;
  3458 
  3459 * the simplifier is now installed
  3460 
  3461 * the axiom system has been generalized (thanks to Soren Heilmann)
  3462 
  3463 * the classical reasoner now has a default rule database
  3464 
  3465 
  3466 *** ZF ***
  3467 
  3468 * new primrec section allows primitive recursive functions to be given
  3469 directly (as in HOL) over datatypes and the natural numbers;
  3470 
  3471 * new tactics induct_tac and exhaust_tac for induction (or case
  3472 analysis) over datatypes and the natural numbers;
  3473 
  3474 * the datatype declaration of type T now defines the recursor T_rec;
  3475 
  3476 * simplification automatically does freeness reasoning for datatype
  3477 constructors;
  3478 
  3479 * automatic type-inference, with AddTCs command to insert new
  3480 type-checking rules;
  3481 
  3482 * datatype introduction rules are now added as Safe Introduction rules
  3483 to the claset;
  3484 
  3485 * the syntax "if P then x else y" is now available in addition to
  3486 if(P,x,y);
  3487 
  3488 
  3489 *** Internal programming interfaces ***
  3490 
  3491 * tuned simplifier trace output; new flag debug_simp;
  3492 
  3493 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3494 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3495 
  3496 * AxClass.axclass_tac lost the theory argument;
  3497 
  3498 * tuned current_goals_markers semantics: begin / end goal avoids
  3499 printing empty lines;
  3500 
  3501 * removed prs and prs_fn hook, which was broken because it did not
  3502 include \n in its semantics, forcing writeln to add one
  3503 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3504 string -> unit if you really want to output text without newline;
  3505 
  3506 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3507 plain output, interface builders may have to enable 'isabelle_font'
  3508 mode to get Isabelle font glyphs as before;
  3509 
  3510 * refined token_translation interface; INCOMPATIBILITY: output length
  3511 now of type real instead of int;
  3512 
  3513 * theory loader actions may be traced via new ThyInfo.add_hook
  3514 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3515 your own database of information attached to *whole* theories -- as
  3516 opposed to intra-theory data slots offered via TheoryDataFun;
  3517 
  3518 * proper handling of dangling sort hypotheses (at last!);
  3519 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3520 extra sort hypotheses that can be witnessed from the type signature;
  3521 the force_strip_shyps flag is gone, any remaining shyps are simply
  3522 left in the theorem (with a warning issued by strip_shyps_warning);
  3523 
  3524 
  3525 
  3526 New in Isabelle98-1 (October 1998)
  3527 ----------------------------------
  3528 
  3529 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3530 
  3531 * several changes of automated proof tools;
  3532 
  3533 * HOL: major changes to the inductive and datatype packages, including
  3534 some minor incompatibilities of theory syntax;
  3535 
  3536 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3537 called `inj_on';
  3538 
  3539 * HOL: removed duplicate thms in Arith:
  3540   less_imp_add_less  should be replaced by  trans_less_add1
  3541   le_imp_add_le      should be replaced by  trans_le_add1
  3542 
  3543 * HOL: unary minus is now overloaded (new type constraints may be
  3544 required);
  3545 
  3546 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3547 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3548 now taken as an integer constant.
  3549 
  3550 * Pure: ML function 'theory_of' renamed to 'theory';
  3551 
  3552 
  3553 *** Proof tools ***
  3554 
  3555 * Simplifier:
  3556   1. Asm_full_simp_tac is now more aggressive.
  3557      1. It will sometimes reorient premises if that increases their power to
  3558         simplify.
  3559      2. It does no longer proceed strictly from left to right but may also
  3560         rotate premises to achieve further simplification.
  3561      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3562      old Asm_full_simp_tac in that it does not rotate premises.
  3563   2. The simplifier now knows a little bit about nat-arithmetic.
  3564 
  3565 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3566 allows for selected deletion of wrappers, by introduction of names for
  3567 wrapper functionals.  This implies that addbefore, addSbefore,
  3568 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3569 and that adding two tactics with the same name overwrites the first
  3570 one (emitting a warning).
  3571   type wrapper = (int -> tactic) -> (int -> tactic)
  3572   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3573   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3574   delWrapper, delSWrapper: claset *  string            -> claset
  3575   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3576 
  3577 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3578 semantics; addbefore now affects only the unsafe part of step_tac
  3579 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3580 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3581 by Force_tac;
  3582 
  3583 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3584 compWrapper; added safe wrapper (and access functions for it);
  3585 
  3586 * HOL/split_all_tac is now much faster and fails if there is nothing
  3587 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3588 and the names of the automatically generated variables have changed.
  3589 split_all_tac has moved within claset() from unsafe wrappers to safe
  3590 wrappers, which means that !!-bound variables are split much more
  3591 aggressively, and safe_tac and clarify_tac now split such variables.
  3592 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3593 Note: the same holds for record_split_tac, which does the job of
  3594 split_all_tac for record fields.
  3595 
  3596 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3597 permanently to the default simpset using Addsplits just like
  3598 Addsimps. They can be removed via Delsplits just like
  3599 Delsimps. Lower-case versions are also available.
  3600 
  3601 * HOL/Simplifier: The rule split_if is now part of the default
  3602 simpset. This means that the simplifier will eliminate all occurrences
  3603 of if-then-else in the conclusion of a goal. To prevent this, you can
  3604 either remove split_if completely from the default simpset by
  3605 `Delsplits [split_if]' or remove it in a specific call of the
  3606 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3607 other case splitting rules to/from the default simpset: every datatype
  3608 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3609 t is the name of the datatype).
  3610 
  3611 * Classical reasoner / Simplifier combination: new force_tac (and
  3612 derivatives Force_tac, force) combines rewriting and classical
  3613 reasoning (and whatever other tools) similarly to auto_tac, but is
  3614 aimed to solve the given subgoal completely.
  3615 
  3616 
  3617 *** General ***
  3618 
  3619 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3620 and `goalw': the theory is no longer needed as an explicit argument -
  3621 the current theory context is used; assumptions are no longer returned
  3622 at the ML-level unless one of them starts with ==> or !!; it is
  3623 recommended to convert to these new commands using isatool fixgoal
  3624 (backup your sources first!);
  3625 
  3626 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3627 the current theory context, and 'theory' to lookup stored theories;
  3628 
  3629 * new theory section 'locale' for declaring constants, assumptions and
  3630 definitions that have local scope;
  3631 
  3632 * new theory section 'nonterminals' for purely syntactic types;
  3633 
  3634 * new theory section 'setup' for generic ML setup functions
  3635 (e.g. package initialization);
  3636 
  3637 * the distribution now includes Isabelle icons: see
  3638 lib/logo/isabelle-{small,tiny}.xpm;
  3639 
  3640 * isatool install - install binaries with absolute references to
  3641 ISABELLE_HOME/bin;
  3642 
  3643 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3644 
  3645 * print mode 'emacs' reserved for Isamode;
  3646 
  3647 * support multiple print (ast) translations per constant name;
  3648 
  3649 * theorems involving oracles are now printed with a suffixed [!];
  3650 
  3651 
  3652 *** HOL ***
  3653 
  3654 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3655 
  3656 * HOL/inductive package reorganized and improved: now supports mutual
  3657 definitions such as
  3658 
  3659   inductive EVEN ODD
  3660     intrs
  3661       null "0 : EVEN"
  3662       oddI "n : EVEN ==> Suc n : ODD"
  3663       evenI "n : ODD ==> Suc n : EVEN"
  3664 
  3665 new theorem list "elims" contains an elimination rule for each of the
  3666 recursive sets; inductive definitions now handle disjunctive premises
  3667 correctly (also ZF);
  3668 
  3669 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3670 "mutual_induct" no longer exists - the induction rule is always
  3671 contained in "induct";
  3672 
  3673 
  3674 * HOL/datatype package re-implemented and greatly improved: now
  3675 supports mutually recursive datatypes such as
  3676 
  3677   datatype
  3678     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3679             | SUM ('a aexp) ('a aexp)
  3680             | DIFF ('a aexp) ('a aexp)
  3681             | NUM 'a
  3682   and
  3683     'a bexp = LESS ('a aexp) ('a aexp)
  3684             | AND ('a bexp) ('a bexp)
  3685             | OR ('a bexp) ('a bexp)
  3686 
  3687 as well as indirectly recursive datatypes such as
  3688 
  3689   datatype
  3690     ('a, 'b) term = Var 'a
  3691                   | App 'b ((('a, 'b) term) list)
  3692 
  3693 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3694 induction on mutually / indirectly recursive datatypes.
  3695 
  3696 Primrec equations are now stored in theory and can be accessed via
  3697 <function_name>.simps.
  3698 
  3699 INCOMPATIBILITIES:
  3700 
  3701   - Theories using datatypes must now have theory Datatype as an
  3702     ancestor.
  3703   - The specific <typename>.induct_tac no longer exists - use the
  3704     generic induct_tac instead.
  3705   - natE has been renamed to nat.exhaust - use exhaust_tac
  3706     instead of res_inst_tac ... natE. Note that the variable
  3707     names in nat.exhaust differ from the names in natE, this
  3708     may cause some "fragile" proofs to fail.
  3709   - The theorems split_<typename>_case and split_<typename>_case_asm
  3710     have been renamed to <typename>.split and <typename>.split_asm.
  3711   - Since default sorts of type variables are now handled correctly,
  3712     some datatype definitions may have to be annotated with explicit
  3713     sort constraints.
  3714   - Primrec definitions no longer require function name and type
  3715     of recursive argument.
  3716 
  3717 Consider using isatool fixdatatype to adapt your theories and proof
  3718 scripts to the new package (backup your sources first!).
  3719 
  3720 
  3721 * HOL/record package: considerably improved implementation; now
  3722 includes concrete syntax for record types, terms, updates; theorems
  3723 for surjective pairing and splitting !!-bound record variables; proof
  3724 support is as follows:
  3725 
  3726   1) standard conversions (selectors or updates applied to record
  3727 constructor terms) are part of the standard simpset;
  3728 
  3729   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3730 made part of standard simpset and claset via addIffs;
  3731 
  3732   3) a tactic for record field splitting (record_split_tac) is part of
  3733 the standard claset (addSWrapper);
  3734 
  3735 To get a better idea about these rules you may retrieve them via
  3736 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3737 the name of your record type.
  3738 
  3739 The split tactic 3) conceptually simplifies by the following rule:
  3740 
  3741   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3742 
  3743 Thus any record variable that is bound by meta-all will automatically
  3744 blow up into some record constructor term, consequently the
  3745 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3746 solve record problems automatically.
  3747 
  3748 
  3749 * reorganized the main HOL image: HOL/Integ and String loaded by
  3750 default; theory Main includes everything;
  3751 
  3752 * automatic simplification of integer sums and comparisons, using cancellation;
  3753 
  3754 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3755 
  3756 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3757 
  3758 * many new identities for unions, intersections, set difference, etc.;
  3759 
  3760 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3761 called split_if, split_split, split_sum_case and split_nat_case (to go
  3762 with add/delsplits);
  3763 
  3764 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3765 (?x::unit) = (); this is made part of the default simpset, which COULD
  3766 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3767 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3768 unit_abs_eta_conv is added in order to counter the effect of
  3769 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3770 %u.f();
  3771 
  3772 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3773 makes more sense);
  3774 
  3775 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3776   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3777   disjointness reasoning but breaking a few old proofs.
  3778 
  3779 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3780 to 'converse' from 'inverse' (for compatibility with ZF and some
  3781 literature);
  3782 
  3783 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3784 the well-founded relation;
  3785 
  3786 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3787     Compl A.  The "Compl" syntax remains available as input syntax for this
  3788     release ONLY.
  3789 
  3790 * HOL/Update: new theory of function updates:
  3791     f(a:=b) == %x. if x=a then b else f x
  3792 may also be iterated as in f(a:=b,c:=d,...);
  3793 
  3794 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3795 
  3796 * HOL/List:
  3797   - new function list_update written xs[i:=v] that updates the i-th
  3798     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3799   - new function `upt' written [i..j(] which generates the list
  3800     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3801     bound write [i..j], which is a shorthand for [i..j+1(].
  3802   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3803 
  3804 * HOL/Arith:
  3805   - removed 'pred' (predecessor) function;
  3806   - generalized some theorems about n-1;
  3807   - many new laws about "div" and "mod";
  3808   - new laws about greatest common divisors (see theory ex/Primes);
  3809 
  3810 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3811 instead of "inverse";
  3812 
  3813 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3814   of the multiset ordering;
  3815 
  3816 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3817   (not included by default);
  3818 
  3819 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3820 
  3821 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3822   programs, i.e. different program variables may have different types.
  3823 
  3824 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3825   [previously, this check worked only if the rewrite rule was unconditional]
  3826   Now rew can involve either definitions or equalities (either == or =).
  3827 
  3828 
  3829 *** ZF ***
  3830 
  3831 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3832   only the theorems proved on ZF.ML;
  3833 
  3834 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3835   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3836   disjointness reasoning but breaking a few old proofs.
  3837 
  3838 * ZF/Update: new theory of function updates
  3839     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3840   may also be iterated as in f(a:=b,c:=d,...);
  3841 
  3842 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3843 
  3844 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3845   [previously, this check worked only if the rewrite rule was unconditional]
  3846   Now rew can involve either definitions or equalities (either == or =).
  3847 
  3848 * case_tac provided for compatibility with HOL
  3849     (like the old excluded_middle_tac, but with subgoals swapped)
  3850 
  3851 
  3852 *** Internal programming interfaces ***
  3853 
  3854 * Pure: several new basic modules made available for general use, see
  3855 also src/Pure/README;
  3856 
  3857 * improved the theory data mechanism to support encapsulation (data
  3858 kind name replaced by private Object.kind, acting as authorization
  3859 key); new type-safe user interface via functor TheoryDataFun; generic
  3860 print_data function becomes basically useless;
  3861 
  3862 * removed global_names compatibility flag -- all theory declarations
  3863 are qualified by default;
  3864 
  3865 * module Pure/Syntax now offers quote / antiquote translation
  3866 functions (useful for Hoare logic etc. with implicit dependencies);
  3867 see HOL/ex/Antiquote for an example use;
  3868 
  3869 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3870 cterm -> thm;
  3871 
  3872 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3873 subgoal;
  3874 
  3875 * Display.print_goals function moved to Locale.print_goals;
  3876 
  3877 * standard print function for goals supports current_goals_markers
  3878 variable for marking begin of proof, end of proof, start of goal; the
  3879 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3880 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3881 for example;
  3882 
  3883 
  3884 
  3885 New in Isabelle98 (January 1998)
  3886 --------------------------------
  3887 
  3888 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3889 
  3890 * changed lexical syntax of terms / types: dots made part of long
  3891 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3892 
  3893 * simpset (and claset) reference variable replaced by functions
  3894 simpset / simpset_ref;
  3895 
  3896 * no longer supports theory aliases (via merge) and non-trivial
  3897 implicit merge of thms' signatures;
  3898 
  3899 * most internal names of constants changed due to qualified names;
  3900 
  3901 * changed Pure/Sequence interface (see Pure/seq.ML);
  3902 
  3903 
  3904 *** General Changes ***
  3905 
  3906 * hierachically structured name spaces (for consts, types, axms, thms
  3907 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3908 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3909 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3910 long_names for fully qualified output names; NOTE: ML programs
  3911 (special tactics, packages etc.) referring to internal names may have
  3912 to be adapted to cope with fully qualified names; in case of severe
  3913 backward campatibility problems try setting 'global_names' at compile
  3914 time to have enrything declared within a flat name space; one may also
  3915 fine tune name declarations in theories via the 'global' and 'local'
  3916 section;
  3917 
  3918 * reimplemented the implicit simpset and claset using the new anytype
  3919 data filed in signatures; references simpset:simpset ref etc. are
  3920 replaced by functions simpset:unit->simpset and
  3921 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3922 to patch your ML files accordingly;
  3923 
  3924 * HTML output now includes theory graph data for display with Java
  3925 applet or isatool browser; data generated automatically via isatool
  3926 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3927 
  3928 * defs may now be conditional; improved rewrite_goals_tac to handle
  3929 conditional equations;
  3930 
  3931 * defs now admits additional type arguments, using TYPE('a) syntax;
  3932 
  3933 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3934 creates a new theory node; implicit merge of thms' signatures is
  3935 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3936 transfer:theory->thm->thm in (rare) cases;
  3937 
  3938 * improved handling of draft signatures / theories; draft thms (and
  3939 ctyps, cterms) are automatically promoted to real ones;
  3940 
  3941 * slightly changed interfaces for oracles: admit many per theory, named
  3942 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3943 
  3944 * print_goals: optional output of const types (set show_consts and
  3945 show_types);
  3946 
  3947 * improved output of warnings (###) and errors (***);
  3948 
  3949 * subgoal_tac displays a warning if the new subgoal has type variables;
  3950 
  3951 * removed old README and Makefiles;
  3952 
  3953 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3954 
  3955 * removed obsolete init_pps and init_database;
  3956 
  3957 * deleted the obsolete tactical STATE, which was declared by
  3958     fun STATE tacfun st = tacfun st st;
  3959 
  3960 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3961 (which abbreviates $HOME);
  3962 
  3963 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3964 use isatool fixseq to adapt your ML programs (this works for fully
  3965 qualified references to the Sequence structure only!);
  3966 
  3967 * use_thy no longer requires writable current directory; it always
  3968 reloads .ML *and* .thy file, if either one is out of date;
  3969 
  3970 
  3971 *** Classical Reasoner ***
  3972 
  3973 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  3974 tactics that use classical reasoning to simplify a subgoal without
  3975 splitting it into several subgoals;
  3976 
  3977 * Safe_tac: like safe_tac but uses the default claset;
  3978 
  3979 
  3980 *** Simplifier ***
  3981 
  3982 * added simplification meta rules:
  3983     (asm_)(full_)simplify: simpset -> thm -> thm;
  3984 
  3985 * simplifier.ML no longer part of Pure -- has to be loaded by object
  3986 logics (again);
  3987 
  3988 * added prems argument to simplification procedures;
  3989 
  3990 * HOL, FOL, ZF: added infix function `addsplits':
  3991   instead of `<simpset> setloop (split_tac <thms>)'
  3992   you can simply write `<simpset> addsplits <thms>'
  3993 
  3994 
  3995 *** Syntax ***
  3996 
  3997 * TYPE('a) syntax for type reflection terms;
  3998 
  3999 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4000 
  4001 * pretty printer: changed order of mixfix annotation preference (again!);
  4002 
  4003 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4004 
  4005 
  4006 *** HOL ***
  4007 
  4008 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4009   with `addloop' of the simplifier to faciliate case splitting in premises.
  4010 
  4011 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4012 
  4013 * HOL/Auth: new protocol proofs including some for the Internet
  4014   protocol TLS;
  4015 
  4016 * HOL/Map: new theory of `maps' a la VDM;
  4017 
  4018 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4019 cancelling out common nat summands from =, <, <= (in)equalities, or
  4020 differences; simplification procedures nat_cancel_factor for
  4021 cancelling common factor from =, <, <= (in)equalities over natural
  4022 sums; nat_cancel contains both kinds of procedures, it is installed by
  4023 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4024 
  4025 * HOL/simplifier: terms of the form
  4026   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4027   are rewritten to
  4028   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4029   and those of the form
  4030   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4031   are rewritten to
  4032   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4033 
  4034 * HOL/datatype
  4035   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4036 
  4037   P(t_case f1 ... fn x) =
  4038      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4039         ...
  4040        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4041      )
  4042 
  4043   and a theorem `split_t_case_asm' of the form
  4044 
  4045   P(t_case f1 ... fn x) =
  4046     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4047         ...
  4048        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4049      )
  4050   which can be added to a simpset via `addsplits'. The existing theorems
  4051   expand_list_case and expand_option_case have been renamed to
  4052   split_list_case and split_option_case.
  4053 
  4054 * HOL/Arithmetic:
  4055   - `pred n' is automatically converted to `n-1'.
  4056     Users are strongly encouraged not to use `pred' any longer,
  4057     because it will disappear altogether at some point.
  4058   - Users are strongly encouraged to write "0 < n" rather than
  4059     "n ~= 0". Theorems and proof tools have been modified towards this
  4060     `standard'.
  4061 
  4062 * HOL/Lists:
  4063   the function "set_of_list" has been renamed "set" (and its theorems too);
  4064   the function "nth" now takes its arguments in the reverse order and
  4065   has acquired the infix notation "!" as in "xs!n".
  4066 
  4067 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4068 
  4069 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4070   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4071 
  4072 * HOL/record: extensible records with schematic structural subtyping
  4073 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4074 still lacks various theorems and concrete record syntax;
  4075 
  4076 
  4077 *** HOLCF ***
  4078 
  4079 * removed "axioms" and "generated by" sections;
  4080 
  4081 * replaced "ops" section by extended "consts" section, which is capable of
  4082   handling the continuous function space "->" directly;
  4083 
  4084 * domain package:
  4085   . proves theorems immediately and stores them in the theory,
  4086   . creates hierachical name space,
  4087   . now uses normal mixfix annotations (instead of cinfix...),
  4088   . minor changes to some names and values (for consistency),
  4089   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4090   . separator between mutual domain defs: changed "," to "and",
  4091   . improved handling of sort constraints;  now they have to
  4092     appear on the left-hand side of the equations only;
  4093 
  4094 * fixed LAM <x,y,zs>.b syntax;
  4095 
  4096 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4097 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4098 
  4099 
  4100 *** FOL and ZF ***
  4101 
  4102 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4103   with `addloop' of the simplifier to faciliate case splitting in premises.
  4104 
  4105 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4106 in HOL, they strip ALL and --> from proved theorems;
  4107 
  4108 
  4109 
  4110 New in Isabelle94-8 (May 1997)
  4111 ------------------------------
  4112 
  4113 *** General Changes ***
  4114 
  4115 * new utilities to build / run / maintain Isabelle etc. (in parts
  4116 still somewhat experimental); old Makefiles etc. still functional;
  4117 
  4118 * new 'Isabelle System Manual';
  4119 
  4120 * INSTALL text, together with ./configure and ./build scripts;
  4121 
  4122 * reimplemented type inference for greater efficiency, better error
  4123 messages and clean internal interface;
  4124 
  4125 * prlim command for dealing with lots of subgoals (an easier way of
  4126 setting goals_limit);
  4127 
  4128 
  4129 *** Syntax ***
  4130 
  4131 * supports alternative (named) syntax tables (parser and pretty
  4132 printer); internal interface is provided by add_modesyntax(_i);
  4133 
  4134 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4135 be used in conjunction with the Isabelle symbol font; uses the
  4136 "symbols" syntax table;
  4137 
  4138 * added token_translation interface (may translate name tokens in
  4139 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4140 the current print_mode); IMPORTANT: user print translation functions
  4141 are responsible for marking newly introduced bounds
  4142 (Syntax.mark_boundT);
  4143 
  4144 * token translations for modes "xterm" and "xterm_color" that display
  4145 names in bold, underline etc. or colors (which requires a color
  4146 version of xterm);
  4147 
  4148 * infixes may now be declared with names independent of their syntax;
  4149 
  4150 * added typed_print_translation (like print_translation, but may
  4151 access type of constant);
  4152 
  4153 
  4154 *** Classical Reasoner ***
  4155 
  4156 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4157 some limitations.  Blast_tac...
  4158   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4159   + ignores elimination rules that don't have the correct format
  4160         (the conclusion MUST be a formula variable)
  4161   + ignores types, which can make HOL proofs fail
  4162   + rules must not require higher-order unification, e.g. apply_type in ZF
  4163     [message "Function Var's argument not a bound variable" relates to this]
  4164   + its proof strategy is more general but can actually be slower
  4165 
  4166 * substitution with equality assumptions no longer permutes other
  4167 assumptions;
  4168 
  4169 * minor changes in semantics of addafter (now called addaltern); renamed
  4170 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4171 (and access functions for it);
  4172 
  4173 * improved combination of classical reasoner and simplifier:
  4174   + functions for handling clasimpsets
  4175   + improvement of addss: now the simplifier is called _after_ the
  4176     safe steps.
  4177   + safe variant of addss called addSss: uses safe simplifications
  4178     _during_ the safe steps. It is more complete as it allows multiple
  4179     instantiations of unknowns (e.g. with slow_tac).
  4180 
  4181 *** Simplifier ***
  4182 
  4183 * added interface for simplification procedures (functions that
  4184 produce *proven* rewrite rules on the fly, depending on current
  4185 redex);
  4186 
  4187 * ordering on terms as parameter (used for ordered rewriting);
  4188 
  4189 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4190 
  4191 * the solver is now split into a safe and an unsafe part.
  4192 This should be invisible for the normal user, except that the
  4193 functions setsolver and addsolver have been renamed to setSolver and
  4194 addSolver; added safe_asm_full_simp_tac;
  4195 
  4196 
  4197 *** HOL ***
  4198 
  4199 * a generic induction tactic `induct_tac' which works for all datatypes and
  4200 also for type `nat';
  4201 
  4202 * a generic case distinction tactic `exhaust_tac' which works for all
  4203 datatypes and also for type `nat';
  4204 
  4205 * each datatype comes with a function `size';
  4206 
  4207 * patterns in case expressions allow tuple patterns as arguments to
  4208 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4209 
  4210 * primrec now also works with type nat;
  4211 
  4212 * recdef: a new declaration form, allows general recursive functions to be
  4213 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4214 
  4215 * the constant for negation has been renamed from "not" to "Not" to
  4216 harmonize with FOL, ZF, LK, etc.;
  4217 
  4218 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4219 infinite lists;
  4220 
  4221 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4222 
  4223 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4224 problems in commutative rings, using axiomatic type classes for + and *;
  4225 
  4226 * more examples in HOL/MiniML and HOL/Auth;
  4227 
  4228 * more default rewrite rules for quantifiers, union/intersection;
  4229 
  4230 * a new constant `arbitrary == @x.False';
  4231 
  4232 * HOLCF/IOA replaces old HOL/IOA;
  4233 
  4234 * HOLCF changes: derived all rules and arities
  4235   + axiomatic type classes instead of classes
  4236   + typedef instead of faking type definitions
  4237   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4238   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4239   + eliminated the types void, one, tr
  4240   + use unit lift and bool lift (with translations) instead of one and tr
  4241   + eliminated blift from Lift3.thy (use Def instead of blift)
  4242   all eliminated rules are derived as theorems --> no visible changes ;
  4243 
  4244 
  4245 *** ZF ***
  4246 
  4247 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4248 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4249 as ZF_cs addSIs [equalityI];
  4250 
  4251 
  4252 
  4253 New in Isabelle94-7 (November 96)
  4254 ---------------------------------
  4255 
  4256 * allowing negative levels (as offsets) in prlev and choplev;
  4257 
  4258 * super-linear speedup for large simplifications;
  4259 
  4260 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4261 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4262 FAIL); can suppress it using the command Delsimps (ex_simps @
  4263 all_simps); De Morgan laws are also now included, by default;
  4264 
  4265 * improved printing of ==>  :  ~:
  4266 
  4267 * new object-logic "Sequents" adds linear logic, while replacing LK
  4268 and Modal (thanks to Sara Kalvala);
  4269 
  4270 * HOL/Auth: correctness proofs for authentication protocols;
  4271 
  4272 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4273 examples on HOL/Auth);
  4274 
  4275 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4276 the rewriter and classical reasoner simultaneously;
  4277 
  4278 * function uresult no longer returns theorems in "standard" format;
  4279 regain previous version by: val uresult = standard o uresult;
  4280 
  4281 
  4282 
  4283 New in Isabelle94-6
  4284 -------------------
  4285 
  4286 * oracles -- these establish an interface between Isabelle and trusted
  4287 external reasoners, which may deliver results as theorems;
  4288 
  4289 * proof objects (in particular record all uses of oracles);
  4290 
  4291 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4292 
  4293 * "constdefs" section in theory files;
  4294 
  4295 * "primrec" section (HOL) no longer requires names;
  4296 
  4297 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4298 
  4299 
  4300 
  4301 New in Isabelle94-5
  4302 -------------------
  4303 
  4304 * reduced space requirements;
  4305 
  4306 * automatic HTML generation from theories;
  4307 
  4308 * theory files no longer require "..." (quotes) around most types;
  4309 
  4310 * new examples, including two proofs of the Church-Rosser theorem;
  4311 
  4312 * non-curried (1994) version of HOL is no longer distributed;
  4313 
  4314 
  4315 
  4316 New in Isabelle94-4
  4317 -------------------
  4318 
  4319 * greatly reduced space requirements;
  4320 
  4321 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4322 
  4323 * searchable theorem database (see the section "Retrieving theorems" on
  4324 page 8 of the Reference Manual);
  4325 
  4326 * new examples, including Grabczewski's monumental case study of the
  4327 Axiom of Choice;
  4328 
  4329 * The previous version of HOL renamed to Old_HOL;
  4330 
  4331 * The new version of HOL (previously called CHOL) uses a curried syntax
  4332 for functions.  Application looks like f a b instead of f(a,b);
  4333 
  4334 * Mutually recursive inductive definitions finally work in HOL;
  4335 
  4336 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4337 translates to the operator "split";
  4338 
  4339 
  4340 
  4341 New in Isabelle94-3
  4342 -------------------
  4343 
  4344 * new infix operator, addss, allowing the classical reasoner to
  4345 perform simplification at each step of its search.  Example:
  4346         fast_tac (cs addss ss)
  4347 
  4348 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4349 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4350 look like (a,b) instead of <a,b>;
  4351 
  4352 * PLEASE NOTE: CHOL will eventually replace HOL!
  4353 
  4354 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4355 It translates to the operator "split".  A new theory of integers is available;
  4356 
  4357 * In ZF, integer numerals now denote two's-complement binary integers.
  4358 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4359 
  4360 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4361 of the Axiom of Choice;
  4362 
  4363 
  4364 
  4365 New in Isabelle94-2
  4366 -------------------
  4367 
  4368 * Significantly faster resolution;
  4369 
  4370 * the different sections in a .thy file can now be mixed and repeated
  4371 freely;
  4372 
  4373 * Database of theorems for FOL, HOL and ZF.  New
  4374 commands including qed, qed_goal and bind_thm store theorems in the database.
  4375 
  4376 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4377 a given theory (thms_of), or find out what theory a theorem was proved in
  4378 (theory_of_thm);
  4379 
  4380 * Bugs fixed in the inductive definition and datatype packages;
  4381 
  4382 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4383 and HOL_dup_cs obsolete;
  4384 
  4385 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4386 have been removed;
  4387 
  4388 * Simpler definition of function space in ZF;
  4389 
  4390 * new results about cardinal and ordinal arithmetic in ZF;
  4391 
  4392 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4393 types;
  4394 
  4395 
  4396 $Id$