NEWS
author skalberg
Fri Aug 29 13:18:45 2003 +0200 (2003-08-29)
changeset 14173 a3690aeb79d4
parent 14172 a872d646bf01
child 14175 dbd16ebaf907
permissions -rw-r--r--
Removed the extended digits again.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    10   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    11   (\<a>...\<z>), are now considered normal letters, and can therefore
    12   be used anywhere where an ASCII letter (a...zA...Z) has until
    13   now. COMPATIBILITY: This obviously changes the parsing of some
    14   terms, especially where a symbol has been used as a binder, say
    15   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    16   as an identifier.  Fix it by inserting a space around former
    17   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    18   existing theory and ML files.
    19 
    20 *** HOL ***
    21 
    22 * 'specification' command added, allowing for definition by
    23 specification.
    24 
    25 
    26 New in Isabelle2003 (May 2003)
    27 --------------------------------
    28 
    29 *** General ***
    30 
    31 * Provers/simplifier:
    32 
    33   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    34     Assumptions are now subject to complete mutual simplification,
    35     not just from left to right. The simplifier now preserves
    36     the order of assumptions.
    37 
    38     Potential INCOMPATIBILITY:
    39 
    40     -- simp sometimes diverges where the old version did
    41        not, e.g. invoking simp on the goal
    42 
    43         [| P (f x); y = x; f x = f y |] ==> Q
    44 
    45        now gives rise to the infinite reduction sequence
    46 
    47         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    48 
    49        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    50        kind of problem.
    51 
    52     -- Tactics combining classical reasoner and simplification (such as auto)
    53        are also affected by this change, because many of them rely on
    54        simp. They may sometimes diverge as well or yield a different numbers
    55        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    56        in case of problems. Sometimes subsequent calls to the classical
    57        reasoner will fail because a preceeding call to the simplifier too
    58        eagerly simplified the goal, e.g. deleted redundant premises.
    59 
    60   - The simplifier trace now shows the names of the applied rewrite rules
    61 
    62   - You can limit the number of recursive invocations of the simplifier
    63     during conditional rewriting (where the simplifie tries to solve the
    64     conditions before applying the rewrite rule):
    65     ML "simp_depth_limit := n"
    66     where n is an integer. Thus you can force termination where previously
    67     the simplifier would diverge.
    68 
    69   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
    70 
    71   - No longer aborts on failed congruence proof.  Instead, the
    72     congruence is ignored.
    73 
    74 * Pure: New generic framework for extracting programs from constructive
    75   proofs. See HOL/Extraction.thy for an example instantiation, as well
    76   as HOL/Extraction for some case studies.
    77 
    78 * Pure: The main goal of the proof state is no longer shown by default, only
    79 the subgoals. This behaviour is controlled by a new flag.
    80    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
    81 (ML: Proof.show_main_goal).
    82 
    83 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
    84 rules whose conclusion matches subgoal 1:
    85       PG menu: Isabelle/Isar -> Show me -> matching rules
    86 The rules are ordered by how closely they match the subgoal.
    87 In particular, rules that solve a subgoal outright are displayed first
    88 (or rather last, the way they are printed).
    89 (ML: ProofGeneral.print_intros())
    90 
    91 * Pure: New flag trace_unify_fail causes unification to print
    92 diagnostic information (PG: in trace buffer) when it fails. This is
    93 useful for figuring out why single step proofs like rule, erule or
    94 assumption failed.
    95 
    96 * Pure: Locale specifications now produce predicate definitions
    97 according to the body of text (covering assumptions modulo local
    98 definitions); predicate "loc_axioms" covers newly introduced text,
    99 while "loc" is cumulative wrt. all included locale expressions; the
   100 latter view is presented only on export into the global theory
   101 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   102 on the old view without predicates;
   103 
   104 * Pure: predefined locales "var" and "struct" are useful for sharing
   105 parameters (as in CASL, for example); just specify something like
   106 ``var x + var y + struct M'' as import;
   107 
   108 * Pure: improved thms_containing: proper indexing of facts instead of
   109 raw theorems; check validity of results wrt. current name space;
   110 include local facts of proof configuration (also covers active
   111 locales), cover fixed variables in index; may use "_" in term
   112 specification; an optional limit for the number of printed facts may
   113 be given (the default is 40);
   114 
   115 * Pure: disallow duplicate fact bindings within new-style theory files
   116 (batch-mode only);
   117 
   118 * Provers: improved induct method: assumptions introduced by case
   119 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   120 the goal statement); "foo" still refers to all facts collectively;
   121 
   122 * Provers: the function blast.overloaded has been removed: all constants
   123 are regarded as potentially overloaded, which improves robustness in exchange
   124 for slight decrease in efficiency;
   125 
   126 * Provers/linorder: New generic prover for transitivity reasoning over
   127 linear orders.  Note: this prover is not efficient!
   128 
   129 * Isar: preview of problems to finish 'show' now produce an error
   130 rather than just a warning (in interactive mode);
   131 
   132 
   133 *** HOL ***
   134 
   135 * arith(_tac)
   136 
   137  - Produces a counter example if it cannot prove a goal.
   138    Note that the counter example may be spurious if the goal is not a formula
   139    of quantifier-free linear arithmetic.
   140    In ProofGeneral the counter example appears in the trace buffer.
   141 
   142  - Knows about div k and mod k where k is a numeral of type nat or int.
   143 
   144  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   145    linear arithmetic fails. This takes account of quantifiers and divisibility.
   146    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   147 
   148 * simp's arithmetic capabilities have been enhanced a bit: it now
   149 takes ~= in premises into account (by performing a case split);
   150 
   151 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   152 are distributed over a sum of terms;
   153 
   154 * New tactic "trans_tac" and method "trans" instantiate
   155 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   156 "<=", "<" and "="). 
   157 
   158 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   159 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   160 
   161 * 'typedef' command has new option "open" to suppress the set
   162 definition;
   163 
   164 * functions Min and Max on finite sets have been introduced (theory
   165 Finite_Set);
   166 
   167 * attribute [symmetric] now works for relations as well; it turns
   168 (x,y) : R^-1 into (y,x) : R, and vice versa;
   169 
   170 * induct over a !!-quantified statement (say !!x1..xn):
   171   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   172 
   173 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   174 %x. None. Warning: empty_def now refers to the previously hidden definition
   175 of the empty set.
   176 
   177 * Algebra: formalization of classical algebra.  Intended as base for
   178 any algebraic development in Isabelle.  Currently covers group theory
   179 (up to Sylow's theorem) and ring theory (Universal Property of
   180 Univariate Polynomials).  Contributions welcome;
   181 
   182 * GroupTheory: deleted, since its material has been moved to Algebra;
   183 
   184 * Complex: new directory of the complex numbers with numeric constants, 
   185 nonstandard complex numbers, and some complex analysis, standard and 
   186 nonstandard (Jacques Fleuriot);
   187 
   188 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   189 
   190 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   191 Fleuriot);
   192 
   193 * Real/HahnBanach: updated and adapted to locales;
   194 
   195 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   196 Gray and Kramer);
   197 
   198 * UNITY: added the Meier-Sanders theory of progress sets;
   199 
   200 * MicroJava: bytecode verifier and lightweight bytecode verifier
   201 as abstract algorithms, instantiated to the JVM;
   202 
   203 * Bali: Java source language formalization. Type system, operational
   204 semantics, axiomatic semantics. Supported language features:
   205 classes, interfaces, objects,virtual methods, static methods,
   206 static/instance fields, arrays, access modifiers, definite
   207 assignment, exceptions.
   208 
   209 
   210 *** ZF ***
   211 
   212 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   213 universe, etc.);
   214 
   215 * Main ZF: virtually all theories converted to new-style format;
   216 
   217 
   218 *** ML ***
   219 
   220 * Pure: Tactic.prove provides sane interface for internal proofs;
   221 omits the infamous "standard" operation, so this is more appropriate
   222 than prove_goalw_cterm in many situations (e.g. in simprocs);
   223 
   224 * Pure: improved error reporting of simprocs;
   225 
   226 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   227 up simprocs;
   228 
   229 
   230 *** Document preparation ***
   231 
   232 * uses \par instead of \\ for line breaks in theory text. This may
   233 shift some page breaks in large documents. To get the old behaviour
   234 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   235 
   236 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   237 other packages
   238 
   239 * \<euro> now needs package babel/greek instead of marvosym (which
   240 broke \Rightarrow)
   241 
   242 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   243 textcomp package)
   244 
   245 
   246 New in Isabelle2002 (March 2002)
   247 --------------------------------
   248 
   249 *** Document preparation ***
   250 
   251 * greatly simplified document preparation setup, including more
   252 graceful interpretation of isatool usedir -i/-d/-D options, and more
   253 instructive isatool mkdir; users should basically be able to get
   254 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   255 users may run a separate document processing stage manually like this:
   256 "isatool usedir -D output HOL Test && isatool document Test/output";
   257 
   258 * theory dependency graph may now be incorporated into documents;
   259 isatool usedir -g true will produce session_graph.eps/.pdf for use
   260 with \includegraphics of LaTeX;
   261 
   262 * proper spacing of consecutive markup elements, especially text
   263 blocks after section headings;
   264 
   265 * support bold style (for single symbols only), input syntax is like
   266 this: "\<^bold>\<alpha>" or "\<^bold>A";
   267 
   268 * \<bullet> is now output as bold \cdot by default, which looks much
   269 better in printed text;
   270 
   271 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   272 note that these symbols are currently unavailable in Proof General /
   273 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   274 
   275 * isatool latex no longer depends on changed TEXINPUTS, instead
   276 isatool document copies the Isabelle style files to the target
   277 location;
   278 
   279 
   280 *** Isar ***
   281 
   282 * Pure/Provers: improved proof by cases and induction;
   283   - 'case' command admits impromptu naming of parameters (such as
   284     "case (Suc n)");
   285   - 'induct' method divinates rule instantiation from the inductive
   286     claim; no longer requires excessive ?P bindings for proper
   287     instantiation of cases;
   288   - 'induct' method properly enumerates all possibilities of set/type
   289     rules; as a consequence facts may be also passed through *type*
   290     rules without further ado;
   291   - 'induct' method now derives symbolic cases from the *rulified*
   292     rule (before it used to rulify cases stemming from the internal
   293     atomized version); this means that the context of a non-atomic
   294     statement becomes is included in the hypothesis, avoiding the
   295     slightly cumbersome show "PROP ?case" form;
   296   - 'induct' may now use elim-style induction rules without chaining
   297     facts, using ``missing'' premises from the goal state; this allows
   298     rules stemming from inductive sets to be applied in unstructured
   299     scripts, while still benefitting from proper handling of non-atomic
   300     statements; NB: major inductive premises need to be put first, all
   301     the rest of the goal is passed through the induction;
   302   - 'induct' proper support for mutual induction involving non-atomic
   303     rule statements (uses the new concept of simultaneous goals, see
   304     below);
   305   - append all possible rule selections, but only use the first
   306     success (no backtracking);
   307   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   308   - undeclared rule case names default to numbers 1, 2, 3, ...;
   309   - added 'print_induct_rules' (covered by help item in recent Proof
   310     General versions);
   311   - moved induct/cases attributes to Pure, methods to Provers;
   312   - generic method setup instantiated for FOL and HOL;
   313 
   314 * Pure: support multiple simultaneous goal statements, for example
   315 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   316 meta-level mechanism, this acts as if several individual goals had
   317 been stated separately; in particular common proof methods need to be
   318 repeated in order to cover all claims; note that a single elimination
   319 step is *not* sufficient to establish the two conjunctions, so this
   320 fails:
   321 
   322   assume "A & B" then have A and B ..   (*".." fails*)
   323 
   324 better use "obtain" in situations as above; alternative refer to
   325 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   326 
   327 * Pure: proper integration with ``locales''; unlike the original
   328 version by Florian Kammüller, Isar locales package high-level proof
   329 contexts rather than raw logical ones (e.g. we admit to include
   330 attributes everywhere); operations on locales include merge and
   331 rename; support for implicit arguments (``structures''); simultaneous
   332 type-inference over imports and text; see also HOL/ex/Locales.thy for
   333 some examples;
   334 
   335 * Pure: the following commands have been ``localized'', supporting a
   336 target locale specification "(in name)": 'lemma', 'theorem',
   337 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   338 stored both within the locale and at the theory level (exported and
   339 qualified by the locale name);
   340 
   341 * Pure: theory goals may now be specified in ``long'' form, with
   342 ad-hoc contexts consisting of arbitrary locale elements. for example
   343 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   344 definitions may be given, too); the result is a meta-level rule with
   345 the context elements being discharged in the obvious way;
   346 
   347 * Pure: new proof command 'using' allows to augment currently used
   348 facts after a goal statement ('using' is syntactically analogous to
   349 'apply', but acts on the goal's facts only); this allows chained facts
   350 to be separated into parts given before and after a claim, as in
   351 ``from a and b have C using d and e <proof>'';
   352 
   353 * Pure: renamed "antecedent" case to "rule_context";
   354 
   355 * Pure: new 'judgment' command records explicit information about the
   356 object-logic embedding (used by several tools internally); no longer
   357 use hard-wired "Trueprop";
   358 
   359 * Pure: added 'corollary' command;
   360 
   361 * Pure: fixed 'token_translation' command;
   362 
   363 * Pure: removed obsolete 'exported' attribute;
   364 
   365 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   366 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   367 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   368 
   369 * Pure: method 'atomize' presents local goal premises as object-level
   370 statements (atomic meta-level propositions); setup controlled via
   371 rewrite rules declarations of 'atomize' attribute; example
   372 application: 'induct' method with proper rule statements in improper
   373 proof *scripts*;
   374 
   375 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   376 now consider the syntactic context of assumptions, giving a better
   377 chance to get type-inference of the arguments right (this is
   378 especially important for locales);
   379 
   380 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   381 mode;
   382 
   383 * Pure/obtain: the formal conclusion "thesis", being marked as
   384 ``internal'', may no longer be reference directly in the text;
   385 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   386 situations;
   387 
   388 * Pure: generic 'sym' attribute which declares a rule both as pure
   389 'elim?' and for the 'symmetric' operation;
   390 
   391 * Pure: marginal comments ``--'' may now occur just anywhere in the
   392 text; the fixed correlation with particular command syntax has been
   393 discontinued;
   394 
   395 * Pure: new method 'rules' is particularly well-suited for proof
   396 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   397 but often produces more compact proof terms with less detours;
   398 
   399 * Pure/Provers/classical: simplified integration with pure rule
   400 attributes and methods; the classical "intro?/elim?/dest?"
   401 declarations coincide with the pure ones; the "rule" method no longer
   402 includes classically swapped intros; "intro" and "elim" methods no
   403 longer pick rules from the context; also got rid of ML declarations
   404 AddXIs/AddXEs/AddXDs; all of this has some potential for
   405 INCOMPATIBILITY;
   406 
   407 * Provers/classical: attribute 'swapped' produces classical inversions
   408 of introduction rules;
   409 
   410 * Provers/simplifier: 'simplified' attribute may refer to explicit
   411 rules instead of full simplifier context; 'iff' attribute handles
   412 conditional rules;
   413 
   414 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   415 
   416 * HOL: 'recdef' now fails on unfinished automated proofs, use
   417 "(permissive)" option to recover old behavior;
   418 
   419 * HOL: 'inductive' no longer features separate (collective) attributes
   420 for 'intros' (was found too confusing);
   421 
   422 * HOL: properly declared induction rules less_induct and
   423 wf_induct_rule;
   424 
   425 
   426 *** HOL ***
   427 
   428 * HOL: moved over to sane numeral syntax; the new policy is as
   429 follows:
   430 
   431   - 0 and 1 are polymorphic constants, which are defined on any
   432   numeric type (nat, int, real etc.);
   433 
   434   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   435   binary representation internally;
   436 
   437   - type nat has special constructor Suc, and generally prefers Suc 0
   438   over 1::nat and Suc (Suc 0) over 2::nat;
   439 
   440 This change may cause significant problems of INCOMPATIBILITY; here
   441 are some hints on converting existing sources:
   442 
   443   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   444   entities, so expressions involving "-" (unary or binary minus) need
   445   to be spaced properly;
   446 
   447   - existing occurrences of "1" may need to be constraint "1::nat" or
   448   even replaced by Suc 0; similar for old "2";
   449 
   450   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   451 
   452   - remove all special provisions on numerals in proofs;
   453 
   454 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   455 representation (depends on bin_arith_simps in the default context);
   456 
   457 * HOL: symbolic syntax for x^2 (numeral 2);
   458 
   459 * HOL: the class of all HOL types is now called "type" rather than
   460 "term"; INCOMPATIBILITY, need to adapt references to this type class
   461 in axclass/classes, instance/arities, and (usually rare) occurrences
   462 in typings (of consts etc.); internally the class is called
   463 "HOL.type", ML programs should refer to HOLogic.typeS;
   464 
   465 * HOL/record package improvements:
   466   - new derived operations "fields" to build a partial record section,
   467     "extend" to promote a fixed record to a record scheme, and
   468     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   469     declared as simp by default;
   470   - shared operations ("more", "fields", etc.) now need to be always
   471     qualified) --- potential INCOMPATIBILITY;
   472   - removed "make_scheme" operations (use "make" with "extend") --
   473     INCOMPATIBILITY;
   474   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   475   - provides cases/induct rules for use with corresponding Isar
   476     methods (for concrete records, record schemes, concrete more
   477     parts, and schematic more parts -- in that order);
   478   - internal definitions directly based on a light-weight abstract
   479     theory of product types over typedef rather than datatype;
   480 
   481 * HOL: generic code generator for generating executable ML code from
   482 specifications; specific support for HOL constructs such as inductive
   483 datatypes and sets, as well as recursive functions; can be invoked
   484 via 'generate_code' theory section;
   485 
   486 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   487 
   488 * HOL: consolidated and renamed several theories.  In particular:
   489 	Ord.thy has been absorbed into HOL.thy
   490 	String.thy has been absorbed into List.thy
   491  
   492 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   493 (beware of argument permutation!);
   494 
   495 * HOL: linorder_less_split superseded by linorder_cases;
   496 
   497 * HOL/List: "nodups" renamed to "distinct";
   498 
   499 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   500 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   501   - Ex_def has changed, now need to use some_eq_ex
   502 
   503 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   504 in this (rare) case use:
   505 
   506   delSWrapper "split_all_tac"
   507   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   508 
   509 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   510 MAY FAIL;
   511 
   512 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   513 Isabelle's type classes, ^ on functions and relations has too general
   514 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   515 necessary to attach explicit type constraints;
   516 
   517 * HOL/Relation: the prefix name of the infix "O" has been changed from
   518 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   519 renamed accordingly (eg "compI" -> "rel_compI").
   520 
   521 * HOL: syntax translations now work properly with numerals and records
   522 expressions;
   523 
   524 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   525 of "lam" -- INCOMPATIBILITY;
   526 
   527 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   528 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   529 renamed "Product_Type.unit";
   530 
   531 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   532 
   533 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   534 the "cases" method);
   535 
   536 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   537 Florian Kammüller);
   538 
   539 * HOL/IMP: updated and converted to new-style theory format; several
   540 parts turned into readable document, with proper Isar proof texts and
   541 some explanations (by Gerwin Klein);
   542 
   543 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   544 
   545 * HOL-Hyperreal is now a logic image;
   546 
   547 
   548 *** HOLCF ***
   549 
   550 * Isar: consts/constdefs supports mixfix syntax for continuous
   551 operations;
   552 
   553 * Isar: domain package adapted to new-style theory format, e.g. see
   554 HOLCF/ex/Dnat.thy;
   555 
   556 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   557 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   558 lift.induct_tac, always use UU instead of Undef;
   559 
   560 * HOLCF/IMP: updated and converted to new-style theory;
   561 
   562 
   563 *** ZF ***
   564 
   565 * Isar: proper integration of logic-specific tools and packages,
   566 including theory commands '(co)inductive', '(co)datatype',
   567 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   568 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   569 
   570 * theory Main no longer includes AC; for the Axiom of Choice, base
   571 your theory on Main_ZFC;
   572 
   573 * the integer library now covers quotients and remainders, with many
   574 laws relating division to addition, multiplication, etc.;
   575 
   576 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   577 typeless version of the formalism;
   578 
   579 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   580 format;
   581 
   582 * ZF/Induct: new directory for examples of inductive definitions,
   583 including theory Multiset for multiset orderings; converted to
   584 new-style theory format;
   585 
   586 * ZF: many new theorems about lists, ordinals, etc.;
   587 
   588 
   589 *** General ***
   590 
   591 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   592 variable proof controls level of detail: 0 = no proofs (only oracle
   593 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   594 also ref manual for further ML interfaces;
   595 
   596 * Pure/axclass: removed obsolete ML interface
   597 goal_subclass/goal_arity;
   598 
   599 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   600 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   601 separate tokens, so expressions involving minus need to be spaced
   602 properly;
   603 
   604 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   605 rather than "infixl" or "infixr";
   606 
   607 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   608 sort constraint specifications in type inference; e.g. "x::_::foo"
   609 ensures that the type of "x" is of sort "foo" (but not necessarily a
   610 type variable);
   611 
   612 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   613 control output of nested => (types); the default behavior is
   614 "type_brackets";
   615 
   616 * Pure/syntax: builtin parse translation for "_constify" turns valued
   617 tokens into AST constants;
   618 
   619 * Pure/syntax: prefer later declarations of translations and print
   620 translation functions; potential INCOMPATIBILITY: need to reverse
   621 multiple declarations for same syntax element constant;
   622 
   623 * Pure/show_hyps reset by default (in accordance to existing Isar
   624 practice);
   625 
   626 * Provers/classical: renamed addaltern to addafter, addSaltern to
   627 addSafter;
   628 
   629 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   630 as well;
   631 
   632 * system: tested support for MacOS X; should be able to get Isabelle +
   633 Proof General to work in a plain Terminal after installing Poly/ML
   634 (e.g. from the Isabelle distribution area) and GNU bash alone
   635 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   636 support requires further installations, e.g. from
   637 http://fink.sourceforge.net/);
   638 
   639 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   640 
   641 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   642 of 40 MB), cf. ML_OPTIONS;
   643 
   644 * system: Proof General keywords specification is now part of the
   645 Isabelle distribution (see etc/isar-keywords.el);
   646 
   647 * system: support for persistent Proof General sessions (refrain from
   648 outdating all loaded theories on startup); user may create writable
   649 logic images like this: ``isabelle -q HOL Test'';
   650 
   651 * system: smart selection of Isabelle process versus Isabelle
   652 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   653 run both "isabelle" and "Isabelle" even if file names are badly
   654 damaged (executable inspects the case of the first letter of its own
   655 name); added separate "isabelle-process" and "isabelle-interface";
   656 
   657 * system: refrain from any attempt at filtering input streams; no
   658 longer support ``8bit'' encoding of old isabelle font, instead proper
   659 iso-latin characters may now be used; the related isatools
   660 "symbolinput" and "nonascii" have disappeared as well;
   661 
   662 * system: removed old "xterm" interface (the print modes "xterm" and
   663 "xterm_color" are still available for direct use in a suitable
   664 terminal);
   665 
   666 
   667 
   668 New in Isabelle99-2 (February 2001)
   669 -----------------------------------
   670 
   671 *** Overview of INCOMPATIBILITIES ***
   672 
   673 * HOL: please note that theories in the Library and elsewhere often use the
   674 new-style (Isar) format; to refer to their theorems in an ML script you must
   675 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   676 
   677 * HOL: inductive package no longer splits induction rule aggressively,
   678 but only as far as specified by the introductions given; the old
   679 format may be recovered via ML function complete_split_rule or attribute
   680 'split_rule (complete)';
   681 
   682 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   683 gfp_Tarski to gfp_unfold;
   684 
   685 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   686 
   687 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   688 relation); infix "^^" has been renamed "``"; infix "``" has been
   689 renamed "`"; "univalent" has been renamed "single_valued";
   690 
   691 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   692 operation;
   693 
   694 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   695 
   696 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   697 
   698 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   699 consequence, it is no longer monotonic wrt. the local goal context
   700 (which is now passed through the inductive cases);
   701 
   702 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   703 \<gg> to \<ggreater>;
   704 
   705 
   706 *** Document preparation ***
   707 
   708 * \isabellestyle{NAME} selects version of Isabelle output (currently
   709 available: are "it" for near math-mode best-style output, "sl" for
   710 slanted text style, and "tt" for plain type-writer; if no
   711 \isabellestyle command is given, output is according to slanted
   712 type-writer);
   713 
   714 * support sub/super scripts (for single symbols only), input syntax is
   715 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   716 
   717 * some more standard symbols; see Appendix A of the system manual for
   718 the complete list of symbols defined in isabellesym.sty;
   719 
   720 * improved isabelle style files; more abstract symbol implementation
   721 (should now use \isamath{...} and \isatext{...} in custom symbol
   722 definitions);
   723 
   724 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   725 state; Note that presentation of goal states does not conform to
   726 actual human-readable proof documents.  Please do not include goal
   727 states into document output unless you really know what you are doing!
   728 
   729 * proper indentation of antiquoted output with proportional LaTeX
   730 fonts;
   731 
   732 * no_document ML operator temporarily disables LaTeX document
   733 generation;
   734 
   735 * isatool unsymbolize tunes sources for plain ASCII communication;
   736 
   737 
   738 *** Isar ***
   739 
   740 * Pure: Isar now suffers initial goal statements to contain unbound
   741 schematic variables (this does not conform to actual readable proof
   742 documents, due to unpredictable outcome and non-compositional proof
   743 checking); users who know what they are doing may use schematic goals
   744 for Prolog-style synthesis of proven results;
   745 
   746 * Pure: assumption method (an implicit finishing) now handles actual
   747 rules as well;
   748 
   749 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   750 initial goal, declare "that" only as Pure intro (only for single
   751 steps); the "that" rule assumption may now be involved in implicit
   752 finishing, thus ".." becomes a feasible for trivial obtains;
   753 
   754 * Pure: default proof step now includes 'intro_classes'; thus trivial
   755 instance proofs may be performed by "..";
   756 
   757 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   758 statements as well;
   759 
   760 * Pure: more robust selection of calculational rules;
   761 
   762 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   763 rule (as well as the assumption rule);
   764 
   765 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   766 lemmas, using the graph browser tool;
   767 
   768 * Pure: predict failure of "show" in interactive mode;
   769 
   770 * Pure: 'thms_containing' now takes actual terms as arguments;
   771 
   772 * HOL: improved method 'induct' --- now handles non-atomic goals
   773 (potential INCOMPATIBILITY); tuned error handling;
   774 
   775 * HOL: cases and induct rules now provide explicit hints about the
   776 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   777 any remaining facts are inserted into the goal verbatim;
   778 
   779 * HOL: local contexts (aka cases) may now contain term bindings as
   780 well; the 'cases' and 'induct' methods new provide a ?case binding for
   781 the result to be shown in each case;
   782 
   783 * HOL: added 'recdef_tc' command;
   784 
   785 * isatool convert assists in eliminating legacy ML scripts;
   786 
   787 
   788 *** HOL ***
   789 
   790 * HOL/Library: a collection of generic theories to be used together
   791 with main HOL; the theory loader path already includes this directory
   792 by default; the following existing theories have been moved here:
   793 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   794 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   795 
   796 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   797 modelling and verification task performed in Isabelle/HOL +
   798 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   799 
   800 * HOL/Algebra: special summation operator SUM no longer exists, it has
   801 been replaced by setsum; infix 'assoc' now has priority 50 (like
   802 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   803 'domain', this makes the theory consistent with mathematical
   804 literature;
   805 
   806 * HOL basics: added overloaded operations "inverse" and "divide"
   807 (infix "/"), syntax for generic "abs" operation, generic summation
   808 operator \<Sum>;
   809 
   810 * HOL/typedef: simplified package, provide more useful rules (see also
   811 HOL/subset.thy);
   812 
   813 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   814 now expressed as a proper nested rule (old-style tactic scripts may
   815 require atomize_strip_tac to cope with non-atomic premises);
   816 
   817 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   818 to "split_conv" (old name still available for compatibility);
   819 
   820 * HOL: improved concrete syntax for strings (e.g. allows translation
   821 rules with string literals);
   822 
   823 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   824  and Fleuriot's mechanization of analysis, including the transcendental
   825  functions for the reals;
   826 
   827 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   828 
   829 
   830 *** CTT ***
   831 
   832 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   833 "lam" is displayed as TWO lambda-symbols
   834 
   835 * CTT: theory Main now available, containing everything (that is, Bool
   836 and Arith);
   837 
   838 
   839 *** General ***
   840 
   841 * Pure: the Simplifier has been implemented properly as a derived rule
   842 outside of the actual kernel (at last!); the overall performance
   843 penalty in practical applications is about 50%, while reliability of
   844 the Isabelle inference kernel has been greatly improved;
   845 
   846 * print modes "brackets" and "no_brackets" control output of nested =>
   847 (types) and ==> (props); the default behaviour is "brackets";
   848 
   849 * Provers: fast_tac (and friends) now handle actual object-logic rules
   850 as assumptions as well;
   851 
   852 * system: support Poly/ML 4.0;
   853 
   854 * system: isatool install handles KDE version 1 or 2;
   855 
   856 
   857 
   858 New in Isabelle99-1 (October 2000)
   859 ----------------------------------
   860 
   861 *** Overview of INCOMPATIBILITIES ***
   862 
   863 * HOL: simplification of natural numbers is much changed; to partly
   864 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   865 issue the following ML commands:
   866 
   867   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   868   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   869 
   870 * HOL: simplification no longer dives into case-expressions; this is
   871 controlled by "t.weak_case_cong" for each datatype t;
   872 
   873 * HOL: nat_less_induct renamed to less_induct;
   874 
   875 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   876 fixsome to patch .thy and .ML sources automatically;
   877 
   878   select_equality  -> some_equality
   879   select_eq_Ex     -> some_eq_ex
   880   selectI2EX       -> someI2_ex
   881   selectI2         -> someI2
   882   selectI          -> someI
   883   select1_equality -> some1_equality
   884   Eps_sym_eq       -> some_sym_eq_trivial
   885   Eps_eq           -> some_eq_trivial
   886 
   887 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   888 
   889 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   890 instead);
   891 
   892 * HOL: the recursion equations generated by 'recdef' are now called
   893 f.simps instead of f.rules;
   894 
   895 * HOL: qed_spec_mp now also handles bounded ALL as well;
   896 
   897 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   898 sometimes be needed;
   899 
   900 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   901 
   902 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   903 
   904 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   905 product is now "<*>" instead of "Times"; the lexicographic product is
   906 now "<*lex*>" instead of "**";
   907 
   908 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   909 of main HOL, but was unused); better use HOL's datatype package;
   910 
   911 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   912 the old syntax may be recovered as follows:
   913 
   914   syntax (symbols)
   915     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   916       (infixl "\\<oplus>" 100)
   917 
   918 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   919 
   920 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   921 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   922 internally;
   923 
   924 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   925 changed from A/r to A//r;
   926 
   927 * ZF: new treatment of arithmetic (nat & int) may break some old
   928 proofs;
   929 
   930 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   931 rulify -> rule_format, elimify -> elim_format, ...);
   932 
   933 * Isar/Provers: intro/elim/dest attributes changed; renamed
   934 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   935 should have to change intro!! to intro? only); replaced "delrule" by
   936 "rule del";
   937 
   938 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   939 
   940 * Provers: strengthened force_tac by using new first_best_tac;
   941 
   942 * LaTeX document preparation: several changes of isabelle.sty (see
   943 lib/texinputs);
   944 
   945 
   946 *** Document preparation ***
   947 
   948 * formal comments (text blocks etc.) in new-style theories may now
   949 contain antiquotations of thm/prop/term/typ/text to be presented
   950 according to latex print mode; concrete syntax is like this:
   951 @{term[show_types] "f(x) = a + x"};
   952 
   953 * isatool mkdir provides easy setup of Isabelle session directories,
   954 including proper document sources;
   955 
   956 * generated LaTeX sources are now deleted after successful run
   957 (isatool document -c); may retain a copy somewhere else via -D option
   958 of isatool usedir;
   959 
   960 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   961 style files, achieving self-contained LaTeX sources and simplifying
   962 LaTeX debugging;
   963 
   964 * old-style theories now produce (crude) LaTeX output as well;
   965 
   966 * browser info session directories are now self-contained (may be put
   967 on WWW server seperately); improved graphs of nested sessions; removed
   968 graph for 'all sessions';
   969 
   970 * several improvements in isabelle style files; \isabellestyle{it}
   971 produces fake math mode output; \isamarkupheader is now \section by
   972 default; see lib/texinputs/isabelle.sty etc.;
   973 
   974 
   975 *** Isar ***
   976 
   977 * Isar/Pure: local results and corresponding term bindings are now
   978 subject to Hindley-Milner polymorphism (similar to ML); this
   979 accommodates incremental type-inference very nicely;
   980 
   981 * Isar/Pure: new derived language element 'obtain' supports
   982 generalized existence reasoning;
   983 
   984 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   985 support accumulation of results, without applying any rules yet;
   986 useful to collect intermediate results without explicit name
   987 references, and for use with transitivity rules with more than 2
   988 premises;
   989 
   990 * Isar/Pure: scalable support for case-analysis type proofs: new
   991 'case' language element refers to local contexts symbolically, as
   992 produced by certain proof methods; internally, case names are attached
   993 to theorems as "tags";
   994 
   995 * Isar/Pure: theory command 'hide' removes declarations from
   996 class/type/const name spaces;
   997 
   998 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   999 indicate potential overloading;
  1000 
  1001 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1002 
  1003 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1004 "{a,b,c}" instead of {a,b,c};
  1005 
  1006 * Isar/Pure now provides its own version of intro/elim/dest
  1007 attributes; useful for building new logics, but beware of confusion
  1008 with the version in Provers/classical;
  1009 
  1010 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1011 case name 'antecedent';
  1012 
  1013 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1014 to the current context is now done automatically);
  1015 
  1016 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1017 for definining proof methods in ML;
  1018 
  1019 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1020 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1021 most cases, one should have to change intro!! to intro? only);
  1022 replaced "delrule" by "rule del";
  1023 
  1024 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1025 'symmetric' attribute (the latter supercedes [RS sym]);
  1026 
  1027 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1028 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1029 well (including splits);
  1030 
  1031 * Isar/Provers: Simplifier and Classical methods now support all kind
  1032 of modifiers used in the past, including 'cong', 'iff', etc.
  1033 
  1034 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1035 of Simplifier and Classical reasoner);
  1036 
  1037 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1038 now support named cases; major packages (inductive, datatype, primrec,
  1039 recdef) support case names and properly name parameters;
  1040 
  1041 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1042 monotonicity conditions are extracted to be proven at end of
  1043 calculations;
  1044 
  1045 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1046 method anyway;
  1047 
  1048 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1049 split_if split_if_asm; datatype package provides theorems foo.splits =
  1050 foo.split foo.split_asm for each datatype;
  1051 
  1052 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1053 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1054 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1055 use "(cases (simplified))" method in proper proof texts);
  1056 
  1057 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1058 
  1059 * Isar: names of theorems etc. may be natural numbers as well;
  1060 
  1061 * Isar: 'pr' command: optional arguments for goals_limit and
  1062 ProofContext.prems_limit; no longer prints theory contexts, but only
  1063 proof states;
  1064 
  1065 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1066 additional print modes to be specified; e.g. "pr(latex)" will print
  1067 proof state according to the Isabelle LaTeX style;
  1068 
  1069 * Isar: improved support for emulating tactic scripts, including proof
  1070 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1071 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1072 (for HOL datatypes);
  1073 
  1074 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1075 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1076 'proof method scripts' have to be in depth-first order;
  1077 
  1078 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1079 
  1080 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1081 should instead use individual commands for printing items
  1082 (print_commands, print_methods etc.);
  1083 
  1084 * Isar: added 'nothing' --- the empty list of theorems;
  1085 
  1086 
  1087 *** HOL ***
  1088 
  1089 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1090 corresponding virtual machine and a specification of its bytecode
  1091 verifier and a lightweight bytecode verifier, including proofs of
  1092 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1093 Cornelia Pusch (see also the homepage of project Bali at
  1094 http://isabelle.in.tum.de/Bali/);
  1095 
  1096 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1097 Clemens Ballarin;
  1098 
  1099 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1100 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1101 Rasmussen;
  1102 
  1103 * HOL/Lattice: fundamental concepts of lattice theory and order
  1104 structures, including duals, properties of bounds versus algebraic
  1105 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1106 Theorem for complete lattices etc.; may also serve as a demonstration
  1107 for abstract algebraic reasoning using axiomatic type classes, and
  1108 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1109 
  1110 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1111 von Oheimb;
  1112 
  1113 * HOL/IMPP: extension of IMP with local variables and mutually
  1114 recursive procedures, by David von Oheimb;
  1115 
  1116 * HOL/Lambda: converted into new-style theory and document;
  1117 
  1118 * HOL/ex/Multiquote: example of multiple nested quotations and
  1119 anti-quotations -- basically a generalized version of de-Bruijn
  1120 representation; very useful in avoiding lifting of operations;
  1121 
  1122 * HOL/record: added general record equality rule to simpset; fixed
  1123 select-update simplification procedure to handle extended records as
  1124 well; admit "r" as field name;
  1125 
  1126 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1127 other numeric types and also as the identity of groups, rings, etc.;
  1128 
  1129 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1130 Types nat and int belong to this axclass;
  1131 
  1132 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1133    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1134    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1135   two terms #m*u and #n*u are replaced by #(m+n)*u
  1136     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1137   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1138     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1139 
  1140 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1141 powerful prover for predicate logic but knows nothing of clasets; see
  1142 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1143 
  1144 * HOL: new version of "case_tac" subsumes both boolean case split and
  1145 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1146 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1147 
  1148 * HOL: simplification no longer dives into case-expressions: only the
  1149 selector expression is simplified, but not the remaining arms; to
  1150 enable full simplification of case-expressions for datatype t, you may
  1151 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1152 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1153 
  1154 * HOL/recdef: the recursion equations generated by 'recdef' for
  1155 function 'f' are now called f.simps instead of f.rules; if all
  1156 termination conditions are proved automatically, these simplification
  1157 rules are added to the simpset, as in primrec; rules may be named
  1158 individually as well, resulting in a separate list of theorems for
  1159 each equation;
  1160 
  1161 * HOL/While is a new theory that provides a while-combinator. It
  1162 permits the definition of tail-recursive functions without the
  1163 provision of a termination measure. The latter is necessary once the
  1164 invariant proof rule for while is applied.
  1165 
  1166 * HOL: new (overloaded) notation for the set of elements below/above
  1167 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1168 
  1169 * HOL: theorems impI, allI, ballI bound as "strip";
  1170 
  1171 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1172 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1173 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1174 
  1175 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1176 
  1177 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1178 main HOL, but was unused);
  1179 
  1180 * HOL: fewer consts declared as global (e.g. have to refer to
  1181 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1182 
  1183 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1184 in case of overlap with user translations (e.g. judgements over
  1185 tuples); (note that the underlying logical represenation is still
  1186 bogus);
  1187 
  1188 
  1189 *** ZF ***
  1190 
  1191 * ZF: simplification automatically cancels common terms in arithmetic
  1192 expressions over nat and int;
  1193 
  1194 * ZF: new treatment of nat to minimize type-checking: all operators
  1195 coerce their operands to a natural number using the function natify,
  1196 making the algebraic laws unconditional;
  1197 
  1198 * ZF: as above, for int: operators coerce their operands to an integer
  1199 using the function intify;
  1200 
  1201 * ZF: the integer library now contains many of the usual laws for the
  1202 orderings, including $<=, and monotonicity laws for $+ and $*;
  1203 
  1204 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1205 simplification;
  1206 
  1207 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1208 to the simplifier and classical reasoner simultaneously;
  1209 
  1210 
  1211 *** General ***
  1212 
  1213 * Provers: blast_tac now handles actual object-logic rules as
  1214 assumptions; note that auto_tac uses blast_tac internally as well;
  1215 
  1216 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1217 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1218 
  1219 * Provers: delrules now handles destruct rules as well (no longer need
  1220 explicit make_elim);
  1221 
  1222 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1223   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1224 use instead the strong form,
  1225   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1226 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1227 from destruct-rules;
  1228 
  1229 * Provers: Simplifier.easy_setup provides a fast path to basic
  1230 Simplifier setup for new object-logics;
  1231 
  1232 * Pure: AST translation rules no longer require constant head on LHS;
  1233 
  1234 * Pure: improved name spaces: ambiguous output is qualified; support
  1235 for hiding of names;
  1236 
  1237 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1238 XSYMBOL_HOME; no longer need to do manual configuration in most
  1239 situations;
  1240 
  1241 * system: compression of ML heaps images may now be controlled via -c
  1242 option of isabelle and isatool usedir (currently only observed by
  1243 Poly/ML);
  1244 
  1245 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1246 useful for remote X11);
  1247 
  1248 * system: provide TAGS file for Isabelle sources;
  1249 
  1250 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1251 order;
  1252 
  1253 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1254 timing flag supersedes proof_timing and Toplevel.trace;
  1255 
  1256 * ML: new combinators |>> and |>>> for incremental transformations
  1257 with secondary results (e.g. certain theory extensions):
  1258 
  1259 * ML: PureThy.add_defs gets additional argument to indicate potential
  1260 overloading (usually false);
  1261 
  1262 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1263 results;
  1264 
  1265 
  1266 
  1267 New in Isabelle99 (October 1999)
  1268 --------------------------------
  1269 
  1270 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1271 
  1272 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1273 are no longer simplified.  (This allows the simplifier to unfold recursive
  1274 functional programs.)  To restore the old behaviour, declare
  1275 
  1276     Delcongs [if_weak_cong];
  1277 
  1278 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1279 complement;
  1280 
  1281 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1282 
  1283 * HOL/datatype: mutual_induct_tac no longer exists --
  1284   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1285 
  1286 * HOL/typedef: fixed type inference for representing set; type
  1287 arguments now have to occur explicitly on the rhs as type constraints;
  1288 
  1289 * ZF: The con_defs part of an inductive definition may no longer refer
  1290 to constants declared in the same theory;
  1291 
  1292 * HOL, ZF: the function mk_cases, generated by the inductive
  1293 definition package, has lost an argument.  To simplify its result, it
  1294 uses the default simpset instead of a supplied list of theorems.
  1295 
  1296 * HOL/List: the constructors of type list are now Nil and Cons;
  1297 
  1298 * Simplifier: the type of the infix ML functions
  1299         setSSolver addSSolver setSolver addSolver
  1300 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1301 for packaging solvers. A solver is created via
  1302         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1303 where the string argument is only a comment.
  1304 
  1305 
  1306 *** Proof tools ***
  1307 
  1308 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1309 decision procedure for linear arithmetic. Currently it is used for
  1310 types `nat', `int', and `real' in HOL (see below); it can, should and
  1311 will be instantiated for other types and logics as well.
  1312 
  1313 * The simplifier now accepts rewrite rules with flexible heads, eg
  1314      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1315   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1316   matching.
  1317 
  1318 
  1319 *** General ***
  1320 
  1321 * New Isabelle/Isar subsystem provides an alternative to traditional
  1322 tactical theorem proving; together with the ProofGeneral/isar user
  1323 interface it offers an interactive environment for developing human
  1324 readable proof documents (Isar == Intelligible semi-automated
  1325 reasoning); for further information see isatool doc isar-ref,
  1326 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1327 
  1328 * improved and simplified presentation of theories: better HTML markup
  1329 (including colors), graph views in several sizes; isatool usedir now
  1330 provides a proper interface for user theories (via -P option); actual
  1331 document preparation based on (PDF)LaTeX is available as well (for
  1332 new-style theories only); see isatool doc system for more information;
  1333 
  1334 * native support for Proof General, both for classic Isabelle and
  1335 Isabelle/Isar;
  1336 
  1337 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1338 using the graph browser tool;
  1339 
  1340 * Isabelle manuals now also available as PDF;
  1341 
  1342 * theory loader rewritten from scratch (may not be fully
  1343 bug-compatible); old loadpath variable has been replaced by show_path,
  1344 add_path, del_path, reset_path functions; new operations such as
  1345 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1346 isatool doc ref);
  1347 
  1348 * improved isatool install: option -k creates KDE application icon,
  1349 option -p DIR installs standalone binaries;
  1350 
  1351 * added ML_PLATFORM setting (useful for cross-platform installations);
  1352 more robust handling of platform specific ML images for SML/NJ;
  1353 
  1354 * the settings environment is now statically scoped, i.e. it is never
  1355 created again in sub-processes invoked from isabelle, isatool, or
  1356 Isabelle;
  1357 
  1358 * path element specification '~~' refers to '$ISABELLE_HOME';
  1359 
  1360 * in locales, the "assumes" and "defines" parts may be omitted if
  1361 empty;
  1362 
  1363 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1364 long arrows);
  1365 
  1366 * new print_mode "HTML";
  1367 
  1368 * new flag show_tags controls display of tags of theorems (which are
  1369 basically just comments that may be attached by some tools);
  1370 
  1371 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1372 mode and goal output format:
  1373 
  1374 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1375 244c244
  1376 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1377 ---
  1378 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1379 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1380 181c181
  1381 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1382 ---
  1383 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1384 
  1385 * function bind_thms stores lists of theorems (cf. bind_thm);
  1386 
  1387 * new shorthand tactics ftac, eatac, datac, fatac;
  1388 
  1389 * qed (and friends) now accept "" as result name; in that case the
  1390 theorem is not stored, but proper checks and presentation of the
  1391 result still apply;
  1392 
  1393 * theorem database now also indexes constants "Trueprop", "all",
  1394 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1395 
  1396 
  1397 *** HOL ***
  1398 
  1399 ** HOL arithmetic **
  1400 
  1401 * There are now decision procedures for linear arithmetic over nat and
  1402 int:
  1403 
  1404 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1405 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1406 are treated as atomic; subformulae not involving type `nat' or `int'
  1407 are ignored; quantified subformulae are ignored unless they are
  1408 positive universal or negative existential. The tactic has to be
  1409 invoked by hand and can be a little bit slow. In particular, the
  1410 running time is exponential in the number of occurrences of `min' and
  1411 `max', and `-' on `nat'.
  1412 
  1413 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1414 (negated) (in)equalities among the premises and the conclusion into
  1415 account (i.e. no compound formulae) and does not know about `min' and
  1416 `max', and `-' on `nat'. It is fast and is used automatically by the
  1417 simplifier.
  1418 
  1419 NB: At the moment, these decision procedures do not cope with mixed
  1420 nat/int formulae where the two parts interact, such as `m < n ==>
  1421 int(m) < int(n)'.
  1422 
  1423 * HOL/Numeral provides a generic theory of numerals (encoded
  1424 efficiently as bit strings); setup for types nat/int/real is in place;
  1425 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1426 int, existing theories and proof scripts may require a few additional
  1427 type constraints;
  1428 
  1429 * integer division and remainder can now be performed on constant
  1430 arguments;
  1431 
  1432 * many properties of integer multiplication, division and remainder
  1433 are now available;
  1434 
  1435 * An interface to the Stanford Validity Checker (SVC) is available through the
  1436 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1437 are proved automatically.  SVC must be installed separately, and its results
  1438 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1439 invocation of the underlying oracle).  For SVC see
  1440   http://verify.stanford.edu/SVC
  1441 
  1442 * IsaMakefile: the HOL-Real target now builds an actual image;
  1443 
  1444 
  1445 ** HOL misc **
  1446 
  1447 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1448 (in Isabelle/Isar) -- by Gertrud Bauer;
  1449 
  1450 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1451 analysis for assembly languages with subtypes;
  1452 
  1453 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1454 -- avoids syntactic ambiguities and treats state, transition, and
  1455 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1456 changed syntax and (many) tactics;
  1457 
  1458 * HOL/inductive: Now also handles more general introduction rules such
  1459   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1460   theorems are now maintained within the theory (maintained via the
  1461   "mono" attribute);
  1462 
  1463 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1464   (using function types) such as
  1465 
  1466   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1467 
  1468 * HOL/record: record_simproc (part of the default simpset) takes care
  1469 of selectors applied to updated records; record_split_tac is no longer
  1470 part of the default claset; update_defs may now be removed from the
  1471 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1472 
  1473   claset_ref () := claset() addSWrapper record_split_wrapper;
  1474   Delsimprocs [record_simproc]
  1475 
  1476 * HOL/typedef: fixed type inference for representing set; type
  1477 arguments now have to occur explicitly on the rhs as type constraints;
  1478 
  1479 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1480 names rather than an ML expression;
  1481 
  1482 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1483 supplied later.  Program schemes can be defined, such as
  1484     "While B C s = (if B s then While B C (C s) else s)"
  1485 where the well-founded relation can be chosen after B and C have been given.
  1486 
  1487 * HOL/List: the constructors of type list are now Nil and Cons;
  1488 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1489 course, ML tools referring to List.list.op # etc. have to be adapted;
  1490 
  1491 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1492 disabled by default; run isabelle with option -m HOL to get back to
  1493 the original Gordon/HOL-style output;
  1494 
  1495 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1496 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1497 
  1498 * HOL basic syntax simplified (more orthogonal): all variants of
  1499 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1500 Eps operator is provided as well: "SOME x. P[x]";
  1501 
  1502 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1503 
  1504 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1505 thus available for user theories;
  1506 
  1507 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1508 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1509 time;
  1510 
  1511 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1512 several times and then mp;
  1513 
  1514 
  1515 *** LK ***
  1516 
  1517 * the notation <<...>> is now available as a notation for sequences of
  1518 formulas;
  1519 
  1520 * the simplifier is now installed
  1521 
  1522 * the axiom system has been generalized (thanks to Soren Heilmann)
  1523 
  1524 * the classical reasoner now has a default rule database
  1525 
  1526 
  1527 *** ZF ***
  1528 
  1529 * new primrec section allows primitive recursive functions to be given
  1530 directly (as in HOL) over datatypes and the natural numbers;
  1531 
  1532 * new tactics induct_tac and exhaust_tac for induction (or case
  1533 analysis) over datatypes and the natural numbers;
  1534 
  1535 * the datatype declaration of type T now defines the recursor T_rec;
  1536 
  1537 * simplification automatically does freeness reasoning for datatype
  1538 constructors;
  1539 
  1540 * automatic type-inference, with AddTCs command to insert new
  1541 type-checking rules;
  1542 
  1543 * datatype introduction rules are now added as Safe Introduction rules
  1544 to the claset;
  1545 
  1546 * the syntax "if P then x else y" is now available in addition to
  1547 if(P,x,y);
  1548 
  1549 
  1550 *** Internal programming interfaces ***
  1551 
  1552 * tuned simplifier trace output; new flag debug_simp;
  1553 
  1554 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1555 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1556 
  1557 * AxClass.axclass_tac lost the theory argument;
  1558 
  1559 * tuned current_goals_markers semantics: begin / end goal avoids
  1560 printing empty lines;
  1561 
  1562 * removed prs and prs_fn hook, which was broken because it did not
  1563 include \n in its semantics, forcing writeln to add one
  1564 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1565 string -> unit if you really want to output text without newline;
  1566 
  1567 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1568 plain output, interface builders may have to enable 'isabelle_font'
  1569 mode to get Isabelle font glyphs as before;
  1570 
  1571 * refined token_translation interface; INCOMPATIBILITY: output length
  1572 now of type real instead of int;
  1573 
  1574 * theory loader actions may be traced via new ThyInfo.add_hook
  1575 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1576 your own database of information attached to *whole* theories -- as
  1577 opposed to intra-theory data slots offered via TheoryDataFun;
  1578 
  1579 * proper handling of dangling sort hypotheses (at last!);
  1580 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1581 extra sort hypotheses that can be witnessed from the type signature;
  1582 the force_strip_shyps flag is gone, any remaining shyps are simply
  1583 left in the theorem (with a warning issued by strip_shyps_warning);
  1584 
  1585 
  1586 
  1587 New in Isabelle98-1 (October 1998)
  1588 ----------------------------------
  1589 
  1590 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1591 
  1592 * several changes of automated proof tools;
  1593 
  1594 * HOL: major changes to the inductive and datatype packages, including
  1595 some minor incompatibilities of theory syntax;
  1596 
  1597 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1598 called `inj_on';
  1599 
  1600 * HOL: removed duplicate thms in Arith:
  1601   less_imp_add_less  should be replaced by  trans_less_add1
  1602   le_imp_add_le      should be replaced by  trans_le_add1
  1603 
  1604 * HOL: unary minus is now overloaded (new type constraints may be
  1605 required);
  1606 
  1607 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1608 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1609 now taken as an integer constant.
  1610 
  1611 * Pure: ML function 'theory_of' renamed to 'theory';
  1612 
  1613 
  1614 *** Proof tools ***
  1615 
  1616 * Simplifier:
  1617   1. Asm_full_simp_tac is now more aggressive.
  1618      1. It will sometimes reorient premises if that increases their power to
  1619         simplify.
  1620      2. It does no longer proceed strictly from left to right but may also
  1621         rotate premises to achieve further simplification.
  1622      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1623      old Asm_full_simp_tac in that it does not rotate premises.
  1624   2. The simplifier now knows a little bit about nat-arithmetic.
  1625 
  1626 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1627 allows for selected deletion of wrappers, by introduction of names for
  1628 wrapper functionals.  This implies that addbefore, addSbefore,
  1629 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1630 and that adding two tactics with the same name overwrites the first
  1631 one (emitting a warning).
  1632   type wrapper = (int -> tactic) -> (int -> tactic)
  1633   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1634   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1635   delWrapper, delSWrapper: claset *  string            -> claset
  1636   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1637 
  1638 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1639 semantics; addbefore now affects only the unsafe part of step_tac
  1640 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1641 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1642 by Force_tac;
  1643 
  1644 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1645 compWrapper; added safe wrapper (and access functions for it);
  1646 
  1647 * HOL/split_all_tac is now much faster and fails if there is nothing
  1648 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1649 and the names of the automatically generated variables have changed.
  1650 split_all_tac has moved within claset() from unsafe wrappers to safe
  1651 wrappers, which means that !!-bound variables are split much more
  1652 aggressively, and safe_tac and clarify_tac now split such variables.
  1653 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1654 Note: the same holds for record_split_tac, which does the job of
  1655 split_all_tac for record fields.
  1656 
  1657 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1658 permanently to the default simpset using Addsplits just like
  1659 Addsimps. They can be removed via Delsplits just like
  1660 Delsimps. Lower-case versions are also available.
  1661 
  1662 * HOL/Simplifier: The rule split_if is now part of the default
  1663 simpset. This means that the simplifier will eliminate all occurrences
  1664 of if-then-else in the conclusion of a goal. To prevent this, you can
  1665 either remove split_if completely from the default simpset by
  1666 `Delsplits [split_if]' or remove it in a specific call of the
  1667 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1668 other case splitting rules to/from the default simpset: every datatype
  1669 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1670 t is the name of the datatype).
  1671 
  1672 * Classical reasoner / Simplifier combination: new force_tac (and
  1673 derivatives Force_tac, force) combines rewriting and classical
  1674 reasoning (and whatever other tools) similarly to auto_tac, but is
  1675 aimed to solve the given subgoal completely.
  1676 
  1677 
  1678 *** General ***
  1679 
  1680 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1681 and `goalw': the theory is no longer needed as an explicit argument -
  1682 the current theory context is used; assumptions are no longer returned
  1683 at the ML-level unless one of them starts with ==> or !!; it is
  1684 recommended to convert to these new commands using isatool fixgoal
  1685 (backup your sources first!);
  1686 
  1687 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1688 the current theory context, and 'theory' to lookup stored theories;
  1689 
  1690 * new theory section 'locale' for declaring constants, assumptions and
  1691 definitions that have local scope;
  1692 
  1693 * new theory section 'nonterminals' for purely syntactic types;
  1694 
  1695 * new theory section 'setup' for generic ML setup functions
  1696 (e.g. package initialization);
  1697 
  1698 * the distribution now includes Isabelle icons: see
  1699 lib/logo/isabelle-{small,tiny}.xpm;
  1700 
  1701 * isatool install - install binaries with absolute references to
  1702 ISABELLE_HOME/bin;
  1703 
  1704 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1705 
  1706 * print mode 'emacs' reserved for Isamode;
  1707 
  1708 * support multiple print (ast) translations per constant name;
  1709 
  1710 * theorems involving oracles are now printed with a suffixed [!];
  1711 
  1712 
  1713 *** HOL ***
  1714 
  1715 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1716 
  1717 * HOL/inductive package reorganized and improved: now supports mutual
  1718 definitions such as
  1719 
  1720   inductive EVEN ODD
  1721     intrs
  1722       null "0 : EVEN"
  1723       oddI "n : EVEN ==> Suc n : ODD"
  1724       evenI "n : ODD ==> Suc n : EVEN"
  1725 
  1726 new theorem list "elims" contains an elimination rule for each of the
  1727 recursive sets; inductive definitions now handle disjunctive premises
  1728 correctly (also ZF);
  1729 
  1730 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1731 "mutual_induct" no longer exists - the induction rule is always
  1732 contained in "induct";
  1733 
  1734 
  1735 * HOL/datatype package re-implemented and greatly improved: now
  1736 supports mutually recursive datatypes such as
  1737 
  1738   datatype
  1739     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1740             | SUM ('a aexp) ('a aexp)
  1741             | DIFF ('a aexp) ('a aexp)
  1742             | NUM 'a
  1743   and
  1744     'a bexp = LESS ('a aexp) ('a aexp)
  1745             | AND ('a bexp) ('a bexp)
  1746             | OR ('a bexp) ('a bexp)
  1747 
  1748 as well as indirectly recursive datatypes such as
  1749 
  1750   datatype
  1751     ('a, 'b) term = Var 'a
  1752                   | App 'b ((('a, 'b) term) list)
  1753 
  1754 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1755 induction on mutually / indirectly recursive datatypes.
  1756 
  1757 Primrec equations are now stored in theory and can be accessed via
  1758 <function_name>.simps.
  1759 
  1760 INCOMPATIBILITIES:
  1761 
  1762   - Theories using datatypes must now have theory Datatype as an
  1763     ancestor.
  1764   - The specific <typename>.induct_tac no longer exists - use the
  1765     generic induct_tac instead.
  1766   - natE has been renamed to nat.exhaust - use exhaust_tac
  1767     instead of res_inst_tac ... natE. Note that the variable
  1768     names in nat.exhaust differ from the names in natE, this
  1769     may cause some "fragile" proofs to fail.
  1770   - The theorems split_<typename>_case and split_<typename>_case_asm
  1771     have been renamed to <typename>.split and <typename>.split_asm.
  1772   - Since default sorts of type variables are now handled correctly,
  1773     some datatype definitions may have to be annotated with explicit
  1774     sort constraints.
  1775   - Primrec definitions no longer require function name and type
  1776     of recursive argument.
  1777 
  1778 Consider using isatool fixdatatype to adapt your theories and proof
  1779 scripts to the new package (backup your sources first!).
  1780 
  1781 
  1782 * HOL/record package: considerably improved implementation; now
  1783 includes concrete syntax for record types, terms, updates; theorems
  1784 for surjective pairing and splitting !!-bound record variables; proof
  1785 support is as follows:
  1786 
  1787   1) standard conversions (selectors or updates applied to record
  1788 constructor terms) are part of the standard simpset;
  1789 
  1790   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1791 made part of standard simpset and claset via addIffs;
  1792 
  1793   3) a tactic for record field splitting (record_split_tac) is part of
  1794 the standard claset (addSWrapper);
  1795 
  1796 To get a better idea about these rules you may retrieve them via
  1797 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1798 the name of your record type.
  1799 
  1800 The split tactic 3) conceptually simplifies by the following rule:
  1801 
  1802   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1803 
  1804 Thus any record variable that is bound by meta-all will automatically
  1805 blow up into some record constructor term, consequently the
  1806 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1807 solve record problems automatically.
  1808 
  1809 
  1810 * reorganized the main HOL image: HOL/Integ and String loaded by
  1811 default; theory Main includes everything;
  1812 
  1813 * automatic simplification of integer sums and comparisons, using cancellation;
  1814 
  1815 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1816 
  1817 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1818 
  1819 * many new identities for unions, intersections, set difference, etc.;
  1820 
  1821 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1822 called split_if, split_split, split_sum_case and split_nat_case (to go
  1823 with add/delsplits);
  1824 
  1825 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1826 (?x::unit) = (); this is made part of the default simpset, which COULD
  1827 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1828 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1829 unit_abs_eta_conv is added in order to counter the effect of
  1830 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1831 %u.f();
  1832 
  1833 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1834 makes more sense);
  1835 
  1836 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1837   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1838   disjointness reasoning but breaking a few old proofs.
  1839 
  1840 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1841 to 'converse' from 'inverse' (for compatibility with ZF and some
  1842 literature);
  1843 
  1844 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1845 the well-founded relation;
  1846 
  1847 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1848     Compl A.  The "Compl" syntax remains available as input syntax for this
  1849     release ONLY.
  1850 
  1851 * HOL/Update: new theory of function updates:
  1852     f(a:=b) == %x. if x=a then b else f x
  1853 may also be iterated as in f(a:=b,c:=d,...);
  1854 
  1855 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1856 
  1857 * HOL/List:
  1858   - new function list_update written xs[i:=v] that updates the i-th
  1859     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1860   - new function `upt' written [i..j(] which generates the list
  1861     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1862     bound write [i..j], which is a shorthand for [i..j+1(].
  1863   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1864 
  1865 * HOL/Arith:
  1866   - removed 'pred' (predecessor) function;
  1867   - generalized some theorems about n-1;
  1868   - many new laws about "div" and "mod";
  1869   - new laws about greatest common divisors (see theory ex/Primes);
  1870 
  1871 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1872 instead of "inverse";
  1873 
  1874 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1875   of the multiset ordering;
  1876 
  1877 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1878   (not included by default);
  1879 
  1880 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1881 
  1882 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1883   programs, i.e. different program variables may have different types.
  1884 
  1885 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1886   [previously, this check worked only if the rewrite rule was unconditional]
  1887   Now rew can involve either definitions or equalities (either == or =).
  1888 
  1889 
  1890 *** ZF ***
  1891 
  1892 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1893   only the theorems proved on ZF.ML;
  1894 
  1895 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1896   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1897   disjointness reasoning but breaking a few old proofs.
  1898 
  1899 * ZF/Update: new theory of function updates
  1900     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1901   may also be iterated as in f(a:=b,c:=d,...);
  1902 
  1903 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1904 
  1905 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1906   [previously, this check worked only if the rewrite rule was unconditional]
  1907   Now rew can involve either definitions or equalities (either == or =).
  1908 
  1909 * case_tac provided for compatibility with HOL
  1910     (like the old excluded_middle_tac, but with subgoals swapped)
  1911 
  1912 
  1913 *** Internal programming interfaces ***
  1914 
  1915 * Pure: several new basic modules made available for general use, see
  1916 also src/Pure/README;
  1917 
  1918 * improved the theory data mechanism to support encapsulation (data
  1919 kind name replaced by private Object.kind, acting as authorization
  1920 key); new type-safe user interface via functor TheoryDataFun; generic
  1921 print_data function becomes basically useless;
  1922 
  1923 * removed global_names compatibility flag -- all theory declarations
  1924 are qualified by default;
  1925 
  1926 * module Pure/Syntax now offers quote / antiquote translation
  1927 functions (useful for Hoare logic etc. with implicit dependencies);
  1928 see HOL/ex/Antiquote for an example use;
  1929 
  1930 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1931 cterm -> thm;
  1932 
  1933 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1934 subgoal;
  1935 
  1936 * Display.print_goals function moved to Locale.print_goals;
  1937 
  1938 * standard print function for goals supports current_goals_markers
  1939 variable for marking begin of proof, end of proof, start of goal; the
  1940 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1941 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1942 for example;
  1943 
  1944 
  1945 
  1946 New in Isabelle98 (January 1998)
  1947 --------------------------------
  1948 
  1949 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1950 
  1951 * changed lexical syntax of terms / types: dots made part of long
  1952 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1953 
  1954 * simpset (and claset) reference variable replaced by functions
  1955 simpset / simpset_ref;
  1956 
  1957 * no longer supports theory aliases (via merge) and non-trivial
  1958 implicit merge of thms' signatures;
  1959 
  1960 * most internal names of constants changed due to qualified names;
  1961 
  1962 * changed Pure/Sequence interface (see Pure/seq.ML);
  1963 
  1964 
  1965 *** General Changes ***
  1966 
  1967 * hierachically structured name spaces (for consts, types, axms, thms
  1968 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1969 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1970 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1971 long_names for fully qualified output names; NOTE: ML programs
  1972 (special tactics, packages etc.) referring to internal names may have
  1973 to be adapted to cope with fully qualified names; in case of severe
  1974 backward campatibility problems try setting 'global_names' at compile
  1975 time to have enrything declared within a flat name space; one may also
  1976 fine tune name declarations in theories via the 'global' and 'local'
  1977 section;
  1978 
  1979 * reimplemented the implicit simpset and claset using the new anytype
  1980 data filed in signatures; references simpset:simpset ref etc. are
  1981 replaced by functions simpset:unit->simpset and
  1982 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1983 to patch your ML files accordingly;
  1984 
  1985 * HTML output now includes theory graph data for display with Java
  1986 applet or isatool browser; data generated automatically via isatool
  1987 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1988 
  1989 * defs may now be conditional; improved rewrite_goals_tac to handle
  1990 conditional equations;
  1991 
  1992 * defs now admits additional type arguments, using TYPE('a) syntax;
  1993 
  1994 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1995 creates a new theory node; implicit merge of thms' signatures is
  1996 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1997 transfer:theory->thm->thm in (rare) cases;
  1998 
  1999 * improved handling of draft signatures / theories; draft thms (and
  2000 ctyps, cterms) are automatically promoted to real ones;
  2001 
  2002 * slightly changed interfaces for oracles: admit many per theory, named
  2003 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2004 
  2005 * print_goals: optional output of const types (set show_consts and
  2006 show_types);
  2007 
  2008 * improved output of warnings (###) and errors (***);
  2009 
  2010 * subgoal_tac displays a warning if the new subgoal has type variables;
  2011 
  2012 * removed old README and Makefiles;
  2013 
  2014 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2015 
  2016 * removed obsolete init_pps and init_database;
  2017 
  2018 * deleted the obsolete tactical STATE, which was declared by
  2019     fun STATE tacfun st = tacfun st st;
  2020 
  2021 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2022 (which abbreviates $HOME);
  2023 
  2024 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2025 use isatool fixseq to adapt your ML programs (this works for fully
  2026 qualified references to the Sequence structure only!);
  2027 
  2028 * use_thy no longer requires writable current directory; it always
  2029 reloads .ML *and* .thy file, if either one is out of date;
  2030 
  2031 
  2032 *** Classical Reasoner ***
  2033 
  2034 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2035 tactics that use classical reasoning to simplify a subgoal without
  2036 splitting it into several subgoals;
  2037 
  2038 * Safe_tac: like safe_tac but uses the default claset;
  2039 
  2040 
  2041 *** Simplifier ***
  2042 
  2043 * added simplification meta rules:
  2044     (asm_)(full_)simplify: simpset -> thm -> thm;
  2045 
  2046 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2047 logics (again);
  2048 
  2049 * added prems argument to simplification procedures;
  2050 
  2051 * HOL, FOL, ZF: added infix function `addsplits':
  2052   instead of `<simpset> setloop (split_tac <thms>)'
  2053   you can simply write `<simpset> addsplits <thms>'
  2054 
  2055 
  2056 *** Syntax ***
  2057 
  2058 * TYPE('a) syntax for type reflection terms;
  2059 
  2060 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2061 
  2062 * pretty printer: changed order of mixfix annotation preference (again!);
  2063 
  2064 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2065 
  2066 
  2067 *** HOL ***
  2068 
  2069 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2070   with `addloop' of the simplifier to faciliate case splitting in premises.
  2071 
  2072 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2073 
  2074 * HOL/Auth: new protocol proofs including some for the Internet
  2075   protocol TLS;
  2076 
  2077 * HOL/Map: new theory of `maps' a la VDM;
  2078 
  2079 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2080 cancelling out common nat summands from =, <, <= (in)equalities, or
  2081 differences; simplification procedures nat_cancel_factor for
  2082 cancelling common factor from =, <, <= (in)equalities over natural
  2083 sums; nat_cancel contains both kinds of procedures, it is installed by
  2084 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2085 
  2086 * HOL/simplifier: terms of the form
  2087   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2088   are rewritten to
  2089   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2090   and those of the form
  2091   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2092   are rewritten to
  2093   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2094 
  2095 * HOL/datatype
  2096   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2097 
  2098   P(t_case f1 ... fn x) =
  2099      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2100         ...
  2101        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2102      )
  2103 
  2104   and a theorem `split_t_case_asm' of the form
  2105 
  2106   P(t_case f1 ... fn x) =
  2107     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2108         ...
  2109        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2110      )
  2111   which can be added to a simpset via `addsplits'. The existing theorems
  2112   expand_list_case and expand_option_case have been renamed to
  2113   split_list_case and split_option_case.
  2114 
  2115 * HOL/Arithmetic:
  2116   - `pred n' is automatically converted to `n-1'.
  2117     Users are strongly encouraged not to use `pred' any longer,
  2118     because it will disappear altogether at some point.
  2119   - Users are strongly encouraged to write "0 < n" rather than
  2120     "n ~= 0". Theorems and proof tools have been modified towards this
  2121     `standard'.
  2122 
  2123 * HOL/Lists:
  2124   the function "set_of_list" has been renamed "set" (and its theorems too);
  2125   the function "nth" now takes its arguments in the reverse order and
  2126   has acquired the infix notation "!" as in "xs!n".
  2127 
  2128 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2129 
  2130 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2131   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2132 
  2133 * HOL/record: extensible records with schematic structural subtyping
  2134 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2135 still lacks various theorems and concrete record syntax;
  2136 
  2137 
  2138 *** HOLCF ***
  2139 
  2140 * removed "axioms" and "generated by" sections;
  2141 
  2142 * replaced "ops" section by extended "consts" section, which is capable of
  2143   handling the continuous function space "->" directly;
  2144 
  2145 * domain package:
  2146   . proves theorems immediately and stores them in the theory,
  2147   . creates hierachical name space,
  2148   . now uses normal mixfix annotations (instead of cinfix...),
  2149   . minor changes to some names and values (for consistency),
  2150   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2151   . separator between mutual domain defs: changed "," to "and",
  2152   . improved handling of sort constraints;  now they have to
  2153     appear on the left-hand side of the equations only;
  2154 
  2155 * fixed LAM <x,y,zs>.b syntax;
  2156 
  2157 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2158 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2159 
  2160 
  2161 *** FOL and ZF ***
  2162 
  2163 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2164   with `addloop' of the simplifier to faciliate case splitting in premises.
  2165 
  2166 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2167 in HOL, they strip ALL and --> from proved theorems;
  2168 
  2169 
  2170 
  2171 New in Isabelle94-8 (May 1997)
  2172 ------------------------------
  2173 
  2174 *** General Changes ***
  2175 
  2176 * new utilities to build / run / maintain Isabelle etc. (in parts
  2177 still somewhat experimental); old Makefiles etc. still functional;
  2178 
  2179 * new 'Isabelle System Manual';
  2180 
  2181 * INSTALL text, together with ./configure and ./build scripts;
  2182 
  2183 * reimplemented type inference for greater efficiency, better error
  2184 messages and clean internal interface;
  2185 
  2186 * prlim command for dealing with lots of subgoals (an easier way of
  2187 setting goals_limit);
  2188 
  2189 
  2190 *** Syntax ***
  2191 
  2192 * supports alternative (named) syntax tables (parser and pretty
  2193 printer); internal interface is provided by add_modesyntax(_i);
  2194 
  2195 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2196 be used in conjunction with the Isabelle symbol font; uses the
  2197 "symbols" syntax table;
  2198 
  2199 * added token_translation interface (may translate name tokens in
  2200 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2201 the current print_mode); IMPORTANT: user print translation functions
  2202 are responsible for marking newly introduced bounds
  2203 (Syntax.mark_boundT);
  2204 
  2205 * token translations for modes "xterm" and "xterm_color" that display
  2206 names in bold, underline etc. or colors (which requires a color
  2207 version of xterm);
  2208 
  2209 * infixes may now be declared with names independent of their syntax;
  2210 
  2211 * added typed_print_translation (like print_translation, but may
  2212 access type of constant);
  2213 
  2214 
  2215 *** Classical Reasoner ***
  2216 
  2217 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2218 some limitations.  Blast_tac...
  2219   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2220   + ignores elimination rules that don't have the correct format
  2221         (the conclusion MUST be a formula variable)
  2222   + ignores types, which can make HOL proofs fail
  2223   + rules must not require higher-order unification, e.g. apply_type in ZF
  2224     [message "Function Var's argument not a bound variable" relates to this]
  2225   + its proof strategy is more general but can actually be slower
  2226 
  2227 * substitution with equality assumptions no longer permutes other
  2228 assumptions;
  2229 
  2230 * minor changes in semantics of addafter (now called addaltern); renamed
  2231 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2232 (and access functions for it);
  2233 
  2234 * improved combination of classical reasoner and simplifier:
  2235   + functions for handling clasimpsets
  2236   + improvement of addss: now the simplifier is called _after_ the
  2237     safe steps.
  2238   + safe variant of addss called addSss: uses safe simplifications
  2239     _during_ the safe steps. It is more complete as it allows multiple
  2240     instantiations of unknowns (e.g. with slow_tac).
  2241 
  2242 *** Simplifier ***
  2243 
  2244 * added interface for simplification procedures (functions that
  2245 produce *proven* rewrite rules on the fly, depending on current
  2246 redex);
  2247 
  2248 * ordering on terms as parameter (used for ordered rewriting);
  2249 
  2250 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2251 
  2252 * the solver is now split into a safe and an unsafe part.
  2253 This should be invisible for the normal user, except that the
  2254 functions setsolver and addsolver have been renamed to setSolver and
  2255 addSolver; added safe_asm_full_simp_tac;
  2256 
  2257 
  2258 *** HOL ***
  2259 
  2260 * a generic induction tactic `induct_tac' which works for all datatypes and
  2261 also for type `nat';
  2262 
  2263 * a generic case distinction tactic `exhaust_tac' which works for all
  2264 datatypes and also for type `nat';
  2265 
  2266 * each datatype comes with a function `size';
  2267 
  2268 * patterns in case expressions allow tuple patterns as arguments to
  2269 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2270 
  2271 * primrec now also works with type nat;
  2272 
  2273 * recdef: a new declaration form, allows general recursive functions to be
  2274 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2275 
  2276 * the constant for negation has been renamed from "not" to "Not" to
  2277 harmonize with FOL, ZF, LK, etc.;
  2278 
  2279 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2280 infinite lists;
  2281 
  2282 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2283 
  2284 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2285 problems in commutative rings, using axiomatic type classes for + and *;
  2286 
  2287 * more examples in HOL/MiniML and HOL/Auth;
  2288 
  2289 * more default rewrite rules for quantifiers, union/intersection;
  2290 
  2291 * a new constant `arbitrary == @x.False';
  2292 
  2293 * HOLCF/IOA replaces old HOL/IOA;
  2294 
  2295 * HOLCF changes: derived all rules and arities
  2296   + axiomatic type classes instead of classes
  2297   + typedef instead of faking type definitions
  2298   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2299   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2300   + eliminated the types void, one, tr
  2301   + use unit lift and bool lift (with translations) instead of one and tr
  2302   + eliminated blift from Lift3.thy (use Def instead of blift)
  2303   all eliminated rules are derived as theorems --> no visible changes ;
  2304 
  2305 
  2306 *** ZF ***
  2307 
  2308 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2309 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2310 as ZF_cs addSIs [equalityI];
  2311 
  2312 
  2313 
  2314 New in Isabelle94-7 (November 96)
  2315 ---------------------------------
  2316 
  2317 * allowing negative levels (as offsets) in prlev and choplev;
  2318 
  2319 * super-linear speedup for large simplifications;
  2320 
  2321 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2322 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2323 FAIL); can suppress it using the command Delsimps (ex_simps @
  2324 all_simps); De Morgan laws are also now included, by default;
  2325 
  2326 * improved printing of ==>  :  ~:
  2327 
  2328 * new object-logic "Sequents" adds linear logic, while replacing LK
  2329 and Modal (thanks to Sara Kalvala);
  2330 
  2331 * HOL/Auth: correctness proofs for authentication protocols;
  2332 
  2333 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2334 examples on HOL/Auth);
  2335 
  2336 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2337 the rewriter and classical reasoner simultaneously;
  2338 
  2339 * function uresult no longer returns theorems in "standard" format;
  2340 regain previous version by: val uresult = standard o uresult;
  2341 
  2342 
  2343 
  2344 New in Isabelle94-6
  2345 -------------------
  2346 
  2347 * oracles -- these establish an interface between Isabelle and trusted
  2348 external reasoners, which may deliver results as theorems;
  2349 
  2350 * proof objects (in particular record all uses of oracles);
  2351 
  2352 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2353 
  2354 * "constdefs" section in theory files;
  2355 
  2356 * "primrec" section (HOL) no longer requires names;
  2357 
  2358 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2359 
  2360 
  2361 
  2362 New in Isabelle94-5
  2363 -------------------
  2364 
  2365 * reduced space requirements;
  2366 
  2367 * automatic HTML generation from theories;
  2368 
  2369 * theory files no longer require "..." (quotes) around most types;
  2370 
  2371 * new examples, including two proofs of the Church-Rosser theorem;
  2372 
  2373 * non-curried (1994) version of HOL is no longer distributed;
  2374 
  2375 
  2376 
  2377 New in Isabelle94-4
  2378 -------------------
  2379 
  2380 * greatly reduced space requirements;
  2381 
  2382 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2383 
  2384 * searchable theorem database (see the section "Retrieving theorems" on
  2385 page 8 of the Reference Manual);
  2386 
  2387 * new examples, including Grabczewski's monumental case study of the
  2388 Axiom of Choice;
  2389 
  2390 * The previous version of HOL renamed to Old_HOL;
  2391 
  2392 * The new version of HOL (previously called CHOL) uses a curried syntax
  2393 for functions.  Application looks like f a b instead of f(a,b);
  2394 
  2395 * Mutually recursive inductive definitions finally work in HOL;
  2396 
  2397 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2398 translates to the operator "split";
  2399 
  2400 
  2401 
  2402 New in Isabelle94-3
  2403 -------------------
  2404 
  2405 * new infix operator, addss, allowing the classical reasoner to
  2406 perform simplification at each step of its search.  Example:
  2407         fast_tac (cs addss ss)
  2408 
  2409 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2410 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2411 look like (a,b) instead of <a,b>;
  2412 
  2413 * PLEASE NOTE: CHOL will eventually replace HOL!
  2414 
  2415 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2416 It translates to the operator "split".  A new theory of integers is available;
  2417 
  2418 * In ZF, integer numerals now denote two's-complement binary integers.
  2419 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2420 
  2421 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2422 of the Axiom of Choice;
  2423 
  2424 
  2425 
  2426 New in Isabelle94-2
  2427 -------------------
  2428 
  2429 * Significantly faster resolution;
  2430 
  2431 * the different sections in a .thy file can now be mixed and repeated
  2432 freely;
  2433 
  2434 * Database of theorems for FOL, HOL and ZF.  New
  2435 commands including qed, qed_goal and bind_thm store theorems in the database.
  2436 
  2437 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2438 a given theory (thms_of), or find out what theory a theorem was proved in
  2439 (theory_of_thm);
  2440 
  2441 * Bugs fixed in the inductive definition and datatype packages;
  2442 
  2443 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2444 and HOL_dup_cs obsolete;
  2445 
  2446 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2447 have been removed;
  2448 
  2449 * Simpler definition of function space in ZF;
  2450 
  2451 * new results about cardinal and ordinal arithmetic in ZF;
  2452 
  2453 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2454 types;
  2455 
  2456 
  2457 $Id$