NEWS
author berghofe
Tue Mar 05 18:54:55 2002 +0100 (2002-03-05)
changeset 13023 f869b6822006
parent 12984 6071200efbf6
child 13025 433c57d09d53
permissions -rw-r--r--
Added two paragraphs on "rules" method and code generator.
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2002 (March 2002)
     6 --------------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    14 users may run a separate document processing stage manually like this:
    15 "isatool usedir -D output HOL Test && isatool document Test/output";
    16 
    17 * theory dependency graph may now be incorporated into documents;
    18 isatool usedir -g true will produce session_graph.eps/.pdf for use
    19 with \includegraphics of LaTeX;
    20 
    21 * proper spacing of consecutive markup elements, especially text
    22 blocks after section headings;
    23 
    24 * support bold style (for single symbols only), input syntax is like
    25 this: "\<^bold>\<alpha>" or "\<^bold>A";
    26 
    27 * \<bullet> is now output as bold \cdot by default, which looks much
    28 better in printed text;
    29 
    30 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    31 note that these symbols are currently unavailable in Proof General /
    32 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
    33 
    34 * isatool latex no longer depends on changed TEXINPUTS, instead
    35 isatool document copies the Isabelle style files to the target
    36 location;
    37 
    38 
    39 *** Isar ***
    40 
    41 * Pure/Provers: improved proof by cases and induction;
    42   - 'case' command admits impromptu naming of parameters (such as
    43     "case (Suc n)");
    44   - 'induct' method divinates rule instantiation from the inductive
    45     claim; no longer requires excessive ?P bindings for proper
    46     instantiation of cases;
    47   - 'induct' method properly enumerates all possibilities of set/type
    48     rules; as a consequence facts may be also passed through *type*
    49     rules without further ado;
    50   - 'induct' method now derives symbolic cases from the *rulified*
    51     rule (before it used to rulify cases stemming from the internal
    52     atomized version); this means that the context of a non-atomic
    53     statement becomes is included in the hypothesis, avoiding the
    54     slightly cumbersome show "PROP ?case" form;
    55   - 'induct' may now use elim-style induction rules without chaining
    56     facts, using ``missing'' premises from the goal state; this allows
    57     rules stemming from inductive sets to be applied in unstructured
    58     scripts, while still benefitting from proper handling of non-atomic
    59     statements; NB: major inductive premises need to be put first, all
    60     the rest of the goal is passed through the induction;
    61   - 'induct' proper support for mutual induction involving non-atomic
    62     rule statements (uses the new concept of simultaneous goals, see
    63     below);
    64   - append all possible rule selections, but only use the first
    65     success (no backtracking);
    66   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    67   - undeclared rule case names default to numbers 1, 2, 3, ...;
    68   - added 'print_induct_rules' (covered by help item in recent Proof
    69     General versions);
    70   - moved induct/cases attributes to Pure, methods to Provers;
    71   - generic method setup instantiated for FOL and HOL;
    72 
    73 * Pure: support multiple simultaneous goal statements, for example
    74 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    75 meta-level mechanism, this acts as if several individual goals had
    76 been stated separately; in particular common proof methods need to be
    77 repeated in order to cover all claims; note that a single elimination
    78 step is *not* sufficient to establish the two conjunctions, so this
    79 fails:
    80 
    81   assume "A & B" then have A and B ..   (*".." fails*)
    82 
    83 better use "obtain" in situations as above; alternative refer to
    84 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    85 
    86 * Pure: proper integration with ``locales''; unlike the original
    87 version by Florian Kammüller, Isar locales package high-level proof
    88 contexts rather than raw logical ones (e.g. we admit to include
    89 attributes everywhere); operations on locales include merge and
    90 rename; support for implicit arguments (``structures''); simultaneous
    91 type-inference over imports and text; see also HOL/ex/Locales.thy for
    92 some examples;
    93 
    94 * Pure: the following commands have been ``localized'', supporting a
    95 target locale specification "(in name)": 'lemma', 'theorem',
    96 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
    97 stored both within the locale and at the theory level (exported and
    98 qualified by the locale name);
    99 
   100 * Pure: theory goals may now be specified in ``long'' form, with
   101 ad-hoc contexts consisting of arbitrary locale elements. for example
   102 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   103 definitions may be given, too); the result is a meta-level rule with
   104 the context elements being discharged in the obvious way;
   105 
   106 * Pure: new proof command 'using' allows to augment currently used
   107 facts after a goal statement ('using' is syntactically analogous to
   108 'apply', but acts on the goal's facts only); this allows chained facts
   109 to be separated into parts given before and after a claim, as in
   110 ``from a and b have C using d and e <proof>'';
   111 
   112 * Pure: renamed "antecedent" case to "rule_context";
   113 
   114 * Pure: new 'judgment' command records explicit information about the
   115 object-logic embedding (used by several tools internally); no longer
   116 use hard-wired "Trueprop";
   117 
   118 * Pure: added 'corollary' command;
   119 
   120 * Pure: fixed 'token_translation' command;
   121 
   122 * Pure: removed obsolete 'exported' attribute;
   123 
   124 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   125 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   126 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   127 
   128 * Pure: method 'atomize' presents local goal premises as object-level
   129 statements (atomic meta-level propositions); setup controlled via
   130 rewrite rules declarations of 'atomize' attribute; example
   131 application: 'induct' method with proper rule statements in improper
   132 proof *scripts*;
   133 
   134 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   135 now consider the syntactic context of assumptions, giving a better
   136 chance to get type-inference of the arguments right (this is
   137 especially important for locales);
   138 
   139 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   140 mode;
   141 
   142 * Pure/obtain: the formal conclusion "thesis", being marked as
   143 ``internal'', may no longer be reference directly in the text;
   144 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   145 situations;
   146 
   147 * Pure: generic 'sym' attribute which declares a rule both as pure
   148 'elim?' and for the 'symmetric' operation;
   149 
   150 * Pure: marginal comments ``--'' may now occur just anywhere in the
   151 text; the fixed correlation with particular command syntax has been
   152 discontinued;
   153 
   154 * Pure: new method 'rules' is particularly well-suited for proof
   155 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   156 but often produces more compact proof terms with less detours;
   157 
   158 * Pure/Provers/classical: simplified integration with pure rule
   159 attributes and methods; the classical "intro?/elim?/dest?"
   160 declarations coincide with the pure ones; the "rule" method no longer
   161 includes classically swapped intros; "intro" and "elim" methods no
   162 longer pick rules from the context; also got rid of ML declarations
   163 AddXIs/AddXEs/AddXDs; all of this has some potential for
   164 INCOMPATIBILITY;
   165 
   166 * Provers/classical: attribute 'swapped' produces classical inversions
   167 of introduction rules;
   168 
   169 * Provers/simplifier: 'simplified' attribute may refer to explicit
   170 rules instead of full simplifier context; 'iff' attribute handles
   171 conditional rules;
   172 
   173 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   174 
   175 * HOL: 'recdef' now fails on unfinished automated proofs, use
   176 "(permissive)" option to recover old behavior;
   177 
   178 * HOL: 'inductive' no longer features separate (collective) attributes
   179 for 'intros' (was found too confusing);
   180 
   181 * HOL: properly declared induction rules less_induct and
   182 wf_induct_rule;
   183 
   184 
   185 *** HOL ***
   186 
   187 * HOL: moved over to sane numeral syntax; the new policy is as
   188 follows:
   189 
   190   - 0 and 1 are polymorphic constants, which are defined on any
   191   numeric type (nat, int, real etc.);
   192 
   193   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   194   binary representation internally;
   195 
   196   - type nat has special constructor Suc, and generally prefers Suc 0
   197   over 1::nat and Suc (Suc 0) over 2::nat;
   198 
   199 This change may cause significant problems of INCOMPATIBILITY; here
   200 are some hints on converting existing sources:
   201 
   202   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   203   entities, so expressions involving "-" (unary or binary minus) need
   204   to be spaced properly;
   205 
   206   - existing occurrences of "1" may need to be constraint "1::nat" or
   207   even replaced by Suc 0; similar for old "2";
   208 
   209   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   210 
   211   - remove all special provisions on numerals in proofs;
   212 
   213 * HOL: simp rules nat_number_of expand numerals on nat to Suc/0
   214 representation (depends on bin_arith_simps in the default context);
   215 
   216 * HOL: symbolic syntax for x^2 (numeral 2);
   217 
   218 * HOL: the class of all HOL types is now called "type" rather than
   219 "term"; INCOMPATIBILITY, need to adapt references to this type class
   220 in axclass/classes, instance/arities, and (usually rare) occurrences
   221 in typings (of consts etc.); internally the class is called
   222 "HOL.type", ML programs should refer to HOLogic.typeS;
   223 
   224 * HOL/record package improvements:
   225   - new derived operations "fields" to build a partial record section,
   226     "extend" to promote a fixed record to a record scheme, and
   227     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   228     declared as simp by default;
   229   - shared operations ("more", "fields", etc.) now need to be always
   230     qualified) --- potential INCOMPATIBILITY;
   231   - removed "make_scheme" operations (use "make" with "extend") --
   232     INCOMPATIBILITY;
   233   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   234   - provides cases/induct rules for use with corresponding Isar
   235     methods (for concrete records, record schemes, concrete more
   236     parts, and schematic more parts -- in that order);
   237   - internal definitions directly based on a light-weight abstract
   238     theory of product types over typedef rather than datatype;
   239 
   240 * HOL: generic code generator for generating executable ML code from
   241 specifications; specific support for HOL constructs such as inductive
   242 datatypes and sets, as well as recursive functions; can be invoked
   243 via 'generate_code' theory section;
   244 
   245 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   246 
   247 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   248 (beware of argument permutation!);
   249 
   250 * HOL: linorder_less_split superseded by linorder_cases;
   251 
   252 * HOL/List: "nodups" renamed to "distinct";
   253 
   254 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   255 to peripheral theory "Hilbert_Choice";
   256 
   257 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   258 in this (rare) case use:
   259 
   260   delSWrapper "split_all_tac"
   261   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   262 
   263 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   264 MAY FAIL;
   265 
   266 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   267 Isabelle's type classes, ^ on functions and relations has too general
   268 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   269 necessary to attach explicit type constraints;
   270 
   271 * HOL/Relation: the prefix name of the infix "O" has been changed from
   272 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   273 renamed accordingly (eg "compI" -> "rel_compI").
   274 
   275 * HOL: syntax translations now work properly with numerals and records
   276 expressions;
   277 
   278 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   279 of "lam" -- INCOMPATIBILITY;
   280 
   281 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   282 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   283 renamed "Product_Type.unit";
   284 
   285 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   286 
   287 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   288 the "cases" method);
   289 
   290 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   291 Florian Kammüller);
   292 
   293 * HOL/IMP: updated and converted to new-style theory format; several
   294 parts turned into readable document, with proper Isar proof texts and
   295 some explanations (by Gerwin Klein);
   296 
   297 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   298 
   299 * HOL-Hyperreal is now a logic image;
   300 
   301 
   302 *** HOLCF ***
   303 
   304 * Isar: consts/constdefs supports mixfix syntax for continuous
   305 operations;
   306 
   307 * Isar: domain package adapted to new-style theory format, e.g. see
   308 HOLCF/ex/Dnat.thy;
   309 
   310 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   311 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   312 lift.induct_tac, always use UU instead of Undef;
   313 
   314 * HOLCF/IMP: updated and converted to new-style theory;
   315 
   316 
   317 *** ZF ***
   318 
   319 * Isar: proper integration of logic-specific tools and packages,
   320 including theory commands '(co)inductive', '(co)datatype',
   321 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   322 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   323 
   324 * theory Main no longer includes AC; for the Axiom of Choice, base
   325 your theory on Main_ZFC;
   326 
   327 * the integer library now covers quotients and remainders, with many
   328 laws relating division to addition, multiplication, etc.;
   329 
   330 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   331 typeless version of the formalism;
   332 
   333 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory format;
   334 
   335 * ZF/Induct: new directory for examples of inductive definitions,
   336 including theory Multiset for multiset orderings; converted to
   337 new-style theory format;
   338 
   339 * Many new theorems about lists, ordinals, etc.;
   340 
   341 
   342 *** General ***
   343 
   344 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   345 variable proof controls level of detail: 0 = no proofs (only oracle
   346 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   347 also ref manual for further ML interfaces;
   348 
   349 * Pure/axclass: removed obsolete ML interface
   350 goal_subclass/goal_arity;
   351 
   352 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   353 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   354 separate tokens, so expressions involving minus need to be spaced
   355 properly;
   356 
   357 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   358 rather than "infixl" or "infixr";
   359 
   360 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   361 sort constraint specifications in type inference; e.g. "x::_::foo"
   362 ensures that the type of "x" is of sort "foo" (but not necessarily a
   363 type variable);
   364 
   365 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   366 control output of nested => (types); the default behavior is
   367 "type_brackets";
   368 
   369 * Pure/syntax: builtin parse translation for "_constify" turns valued
   370 tokens into AST constants;
   371 
   372 * Pure/syntax: prefer later declarations of translations and print
   373 translation functions; potential INCOMPATIBILITY: need to reverse
   374 multiple declarations for same syntax element constant;
   375 
   376 * Pure/show_hyps reset by default (in accordance to existing Isar
   377 practice);
   378 
   379 * Provers/classical: renamed addaltern to addafter, addSaltern to
   380 addSafter;
   381 
   382 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   383 as well;
   384 
   385 * system: tested support for MacOS X; should be able to get Isabelle +
   386 Proof General to work in a plain Terminal after installing Poly/ML
   387 (e.g. from the Isabelle distribution area) and GNU bash alone
   388 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   389 support requires further installations, e.g. from
   390 http://fink.sourceforge.net/);
   391 
   392 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   393 
   394 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   395 of 40 MB), cf. ML_OPTIONS;
   396 
   397 * system: Proof General keywords specification is now part of the
   398 Isabelle distribution (see etc/isar-keywords.el);
   399 
   400 * system: support for persistent Proof General sessions (refrain from
   401 outdating all loaded theories on startup); user may create writable
   402 logic images like this: ``isabelle -q HOL Test'';
   403 
   404 * system: smart selection of Isabelle process versus Isabelle
   405 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   406 run both "isabelle" and "Isabelle" even if file names are badly
   407 damaged (executable inspects the case of the first letter of its own
   408 name); added separate "isabelle-process" and "isabelle-interface";
   409 
   410 * system: refrain from any attempt at filtering input streams; no
   411 longer support ``8bit'' encoding of old isabelle font, instead proper
   412 iso-latin characters may now be used; the related isatools
   413 "symbolinput" and "nonascii" have disappeared as well;
   414 
   415 * system: removed old "xterm" interface (the print modes "xterm" and
   416 "xterm_color" are still available for direct use in a suitable
   417 terminal);
   418 
   419 
   420 
   421 New in Isabelle99-2 (February 2001)
   422 -----------------------------------
   423 
   424 *** Overview of INCOMPATIBILITIES ***
   425 
   426 * HOL: please note that theories in the Library and elsewhere often use the
   427 new-style (Isar) format; to refer to their theorems in an ML script you must
   428 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   429 
   430 * HOL: inductive package no longer splits induction rule aggressively,
   431 but only as far as specified by the introductions given; the old
   432 format may be recovered via ML function complete_split_rule or attribute
   433 'split_rule (complete)';
   434 
   435 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   436 gfp_Tarski to gfp_unfold;
   437 
   438 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   439 
   440 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   441 relation); infix "^^" has been renamed "``"; infix "``" has been
   442 renamed "`"; "univalent" has been renamed "single_valued";
   443 
   444 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   445 operation;
   446 
   447 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   448 
   449 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   450 
   451 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   452 consequence, it is no longer monotonic wrt. the local goal context
   453 (which is now passed through the inductive cases);
   454 
   455 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   456 \<gg> to \<ggreater>;
   457 
   458 
   459 *** Document preparation ***
   460 
   461 * \isabellestyle{NAME} selects version of Isabelle output (currently
   462 available: are "it" for near math-mode best-style output, "sl" for
   463 slanted text style, and "tt" for plain type-writer; if no
   464 \isabellestyle command is given, output is according to slanted
   465 type-writer);
   466 
   467 * support sub/super scripts (for single symbols only), input syntax is
   468 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   469 
   470 * some more standard symbols; see Appendix A of the system manual for
   471 the complete list of symbols defined in isabellesym.sty;
   472 
   473 * improved isabelle style files; more abstract symbol implementation
   474 (should now use \isamath{...} and \isatext{...} in custom symbol
   475 definitions);
   476 
   477 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   478 state; Note that presentation of goal states does not conform to
   479 actual human-readable proof documents.  Please do not include goal
   480 states into document output unless you really know what you are doing!
   481 
   482 * proper indentation of antiquoted output with proportional LaTeX
   483 fonts;
   484 
   485 * no_document ML operator temporarily disables LaTeX document
   486 generation;
   487 
   488 * isatool unsymbolize tunes sources for plain ASCII communication;
   489 
   490 
   491 *** Isar ***
   492 
   493 * Pure: Isar now suffers initial goal statements to contain unbound
   494 schematic variables (this does not conform to actual readable proof
   495 documents, due to unpredictable outcome and non-compositional proof
   496 checking); users who know what they are doing may use schematic goals
   497 for Prolog-style synthesis of proven results;
   498 
   499 * Pure: assumption method (an implicit finishing) now handles actual
   500 rules as well;
   501 
   502 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   503 initial goal, declare "that" only as Pure intro (only for single
   504 steps); the "that" rule assumption may now be involved in implicit
   505 finishing, thus ".." becomes a feasible for trivial obtains;
   506 
   507 * Pure: default proof step now includes 'intro_classes'; thus trivial
   508 instance proofs may be performed by "..";
   509 
   510 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   511 statements as well;
   512 
   513 * Pure: more robust selection of calculational rules;
   514 
   515 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   516 rule (as well as the assumption rule);
   517 
   518 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   519 lemmas, using the graph browser tool;
   520 
   521 * Pure: predict failure of "show" in interactive mode;
   522 
   523 * Pure: 'thms_containing' now takes actual terms as arguments;
   524 
   525 * HOL: improved method 'induct' --- now handles non-atomic goals
   526 (potential INCOMPATIBILITY); tuned error handling;
   527 
   528 * HOL: cases and induct rules now provide explicit hints about the
   529 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   530 any remaining facts are inserted into the goal verbatim;
   531 
   532 * HOL: local contexts (aka cases) may now contain term bindings as
   533 well; the 'cases' and 'induct' methods new provide a ?case binding for
   534 the result to be shown in each case;
   535 
   536 * HOL: added 'recdef_tc' command;
   537 
   538 * isatool convert assists in eliminating legacy ML scripts;
   539 
   540 
   541 *** HOL ***
   542 
   543 * HOL/Library: a collection of generic theories to be used together
   544 with main HOL; the theory loader path already includes this directory
   545 by default; the following existing theories have been moved here:
   546 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   547 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   548 
   549 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   550 modelling and verification task performed in Isabelle/HOL +
   551 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   552 
   553 * HOL/Algebra: special summation operator SUM no longer exists, it has
   554 been replaced by setsum; infix 'assoc' now has priority 50 (like
   555 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   556 'domain', this makes the theory consistent with mathematical
   557 literature;
   558 
   559 * HOL basics: added overloaded operations "inverse" and "divide"
   560 (infix "/"), syntax for generic "abs" operation, generic summation
   561 operator \<Sum>;
   562 
   563 * HOL/typedef: simplified package, provide more useful rules (see also
   564 HOL/subset.thy);
   565 
   566 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   567 now expressed as a proper nested rule (old-style tactic scripts may
   568 require atomize_strip_tac to cope with non-atomic premises);
   569 
   570 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   571 to "split_conv" (old name still available for compatibility);
   572 
   573 * HOL: improved concrete syntax for strings (e.g. allows translation
   574 rules with string literals);
   575 
   576 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   577  and Fleuriot's mechanization of analysis, including the transcendental
   578  functions for the reals;
   579 
   580 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   581 
   582 
   583 *** CTT ***
   584 
   585 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   586 "lam" is displayed as TWO lambda-symbols
   587 
   588 * CTT: theory Main now available, containing everything (that is, Bool
   589 and Arith);
   590 
   591 
   592 *** General ***
   593 
   594 * Pure: the Simplifier has been implemented properly as a derived rule
   595 outside of the actual kernel (at last!); the overall performance
   596 penalty in practical applications is about 50%, while reliability of
   597 the Isabelle inference kernel has been greatly improved;
   598 
   599 * print modes "brackets" and "no_brackets" control output of nested =>
   600 (types) and ==> (props); the default behaviour is "brackets";
   601 
   602 * Provers: fast_tac (and friends) now handle actual object-logic rules
   603 as assumptions as well;
   604 
   605 * system: support Poly/ML 4.0;
   606 
   607 * system: isatool install handles KDE version 1 or 2;
   608 
   609 
   610 
   611 New in Isabelle99-1 (October 2000)
   612 ----------------------------------
   613 
   614 *** Overview of INCOMPATIBILITIES ***
   615 
   616 * HOL: simplification of natural numbers is much changed; to partly
   617 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   618 issue the following ML commands:
   619 
   620   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   621   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   622 
   623 * HOL: simplification no longer dives into case-expressions; this is
   624 controlled by "t.weak_case_cong" for each datatype t;
   625 
   626 * HOL: nat_less_induct renamed to less_induct;
   627 
   628 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   629 fixsome to patch .thy and .ML sources automatically;
   630 
   631   select_equality  -> some_equality
   632   select_eq_Ex     -> some_eq_ex
   633   selectI2EX       -> someI2_ex
   634   selectI2         -> someI2
   635   selectI          -> someI
   636   select1_equality -> some1_equality
   637   Eps_sym_eq       -> some_sym_eq_trivial
   638   Eps_eq           -> some_eq_trivial
   639 
   640 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   641 
   642 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   643 instead);
   644 
   645 * HOL: the recursion equations generated by 'recdef' are now called
   646 f.simps instead of f.rules;
   647 
   648 * HOL: qed_spec_mp now also handles bounded ALL as well;
   649 
   650 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   651 sometimes be needed;
   652 
   653 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   654 
   655 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   656 
   657 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   658 product is now "<*>" instead of "Times"; the lexicographic product is
   659 now "<*lex*>" instead of "**";
   660 
   661 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   662 of main HOL, but was unused); better use HOL's datatype package;
   663 
   664 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   665 the old syntax may be recovered as follows:
   666 
   667   syntax (symbols)
   668     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   669       (infixl "\\<oplus>" 100)
   670 
   671 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   672 
   673 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   674 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   675 internally;
   676 
   677 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   678 changed from A/r to A//r;
   679 
   680 * ZF: new treatment of arithmetic (nat & int) may break some old
   681 proofs;
   682 
   683 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   684 rulify -> rule_format, elimify -> elim_format, ...);
   685 
   686 * Isar/Provers: intro/elim/dest attributes changed; renamed
   687 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   688 should have to change intro!! to intro? only); replaced "delrule" by
   689 "rule del";
   690 
   691 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   692 
   693 * Provers: strengthened force_tac by using new first_best_tac;
   694 
   695 * LaTeX document preparation: several changes of isabelle.sty (see
   696 lib/texinputs);
   697 
   698 
   699 *** Document preparation ***
   700 
   701 * formal comments (text blocks etc.) in new-style theories may now
   702 contain antiquotations of thm/prop/term/typ/text to be presented
   703 according to latex print mode; concrete syntax is like this:
   704 @{term[show_types] "f(x) = a + x"};
   705 
   706 * isatool mkdir provides easy setup of Isabelle session directories,
   707 including proper document sources;
   708 
   709 * generated LaTeX sources are now deleted after successful run
   710 (isatool document -c); may retain a copy somewhere else via -D option
   711 of isatool usedir;
   712 
   713 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   714 style files, achieving self-contained LaTeX sources and simplifying
   715 LaTeX debugging;
   716 
   717 * old-style theories now produce (crude) LaTeX output as well;
   718 
   719 * browser info session directories are now self-contained (may be put
   720 on WWW server seperately); improved graphs of nested sessions; removed
   721 graph for 'all sessions';
   722 
   723 * several improvements in isabelle style files; \isabellestyle{it}
   724 produces fake math mode output; \isamarkupheader is now \section by
   725 default; see lib/texinputs/isabelle.sty etc.;
   726 
   727 
   728 *** Isar ***
   729 
   730 * Isar/Pure: local results and corresponding term bindings are now
   731 subject to Hindley-Milner polymorphism (similar to ML); this
   732 accommodates incremental type-inference very nicely;
   733 
   734 * Isar/Pure: new derived language element 'obtain' supports
   735 generalized existence reasoning;
   736 
   737 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   738 support accumulation of results, without applying any rules yet;
   739 useful to collect intermediate results without explicit name
   740 references, and for use with transitivity rules with more than 2
   741 premises;
   742 
   743 * Isar/Pure: scalable support for case-analysis type proofs: new
   744 'case' language element refers to local contexts symbolically, as
   745 produced by certain proof methods; internally, case names are attached
   746 to theorems as "tags";
   747 
   748 * Isar/Pure: theory command 'hide' removes declarations from
   749 class/type/const name spaces;
   750 
   751 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   752 indicate potential overloading;
   753 
   754 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   755 
   756 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   757 "{a,b,c}" instead of {a,b,c};
   758 
   759 * Isar/Pure now provides its own version of intro/elim/dest
   760 attributes; useful for building new logics, but beware of confusion
   761 with the version in Provers/classical;
   762 
   763 * Isar/Pure: the local context of (non-atomic) goals is provided via
   764 case name 'antecedent';
   765 
   766 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   767 to the current context is now done automatically);
   768 
   769 * Isar/Pure: theory command 'method_setup' provides a simple interface
   770 for definining proof methods in ML;
   771 
   772 * Isar/Provers: intro/elim/dest attributes changed; renamed
   773 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   774 most cases, one should have to change intro!! to intro? only);
   775 replaced "delrule" by "rule del";
   776 
   777 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   778 'symmetric' attribute (the latter supercedes [RS sym]);
   779 
   780 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   781 method modifier); 'simp' method: 'only:' modifier removes loopers as
   782 well (including splits);
   783 
   784 * Isar/Provers: Simplifier and Classical methods now support all kind
   785 of modifiers used in the past, including 'cong', 'iff', etc.
   786 
   787 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   788 of Simplifier and Classical reasoner);
   789 
   790 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   791 now support named cases; major packages (inductive, datatype, primrec,
   792 recdef) support case names and properly name parameters;
   793 
   794 * Isar/HOL: new transitivity rules for substitution in inequalities --
   795 monotonicity conditions are extracted to be proven at end of
   796 calculations;
   797 
   798 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   799 method anyway;
   800 
   801 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   802 split_if split_if_asm; datatype package provides theorems foo.splits =
   803 foo.split foo.split_asm for each datatype;
   804 
   805 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   806 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   807 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   808 use "(cases (simplified))" method in proper proof texts);
   809 
   810 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   811 
   812 * Isar: names of theorems etc. may be natural numbers as well;
   813 
   814 * Isar: 'pr' command: optional arguments for goals_limit and
   815 ProofContext.prems_limit; no longer prints theory contexts, but only
   816 proof states;
   817 
   818 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   819 additional print modes to be specified; e.g. "pr(latex)" will print
   820 proof state according to the Isabelle LaTeX style;
   821 
   822 * Isar: improved support for emulating tactic scripts, including proof
   823 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   824 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   825 (for HOL datatypes);
   826 
   827 * Isar: simplified (more robust) goal selection of proof methods: 1st
   828 goal, all goals, or explicit goal specifier (tactic emulation); thus
   829 'proof method scripts' have to be in depth-first order;
   830 
   831 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   832 
   833 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   834 should instead use individual commands for printing items
   835 (print_commands, print_methods etc.);
   836 
   837 * Isar: added 'nothing' --- the empty list of theorems;
   838 
   839 
   840 *** HOL ***
   841 
   842 * HOL/MicroJava: formalization of a fragment of Java, together with a
   843 corresponding virtual machine and a specification of its bytecode
   844 verifier and a lightweight bytecode verifier, including proofs of
   845 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   846 Cornelia Pusch (see also the homepage of project Bali at
   847 http://isabelle.in.tum.de/Bali/);
   848 
   849 * HOL/Algebra: new theory of rings and univariate polynomials, by
   850 Clemens Ballarin;
   851 
   852 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   853 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   854 Rasmussen;
   855 
   856 * HOL/Lattice: fundamental concepts of lattice theory and order
   857 structures, including duals, properties of bounds versus algebraic
   858 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   859 Theorem for complete lattices etc.; may also serve as a demonstration
   860 for abstract algebraic reasoning using axiomatic type classes, and
   861 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   862 
   863 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   864 von Oheimb;
   865 
   866 * HOL/IMPP: extension of IMP with local variables and mutually
   867 recursive procedures, by David von Oheimb;
   868 
   869 * HOL/Lambda: converted into new-style theory and document;
   870 
   871 * HOL/ex/Multiquote: example of multiple nested quotations and
   872 anti-quotations -- basically a generalized version of de-Bruijn
   873 representation; very useful in avoiding lifting of operations;
   874 
   875 * HOL/record: added general record equality rule to simpset; fixed
   876 select-update simplification procedure to handle extended records as
   877 well; admit "r" as field name;
   878 
   879 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   880 other numeric types and also as the identity of groups, rings, etc.;
   881 
   882 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   883 Types nat and int belong to this axclass;
   884 
   885 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   886    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   887    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   888   two terms #m*u and #n*u are replaced by #(m+n)*u
   889     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   890   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   891     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   892 
   893 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   894 powerful prover for predicate logic but knows nothing of clasets; see
   895 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   896 
   897 * HOL: new version of "case_tac" subsumes both boolean case split and
   898 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   899 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   900 
   901 * HOL: simplification no longer dives into case-expressions: only the
   902 selector expression is simplified, but not the remaining arms; to
   903 enable full simplification of case-expressions for datatype t, you may
   904 remove t.weak_case_cong from the simpset, either globally (Delcongs
   905 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   906 
   907 * HOL/recdef: the recursion equations generated by 'recdef' for
   908 function 'f' are now called f.simps instead of f.rules; if all
   909 termination conditions are proved automatically, these simplification
   910 rules are added to the simpset, as in primrec; rules may be named
   911 individually as well, resulting in a separate list of theorems for
   912 each equation;
   913 
   914 * HOL/While is a new theory that provides a while-combinator. It
   915 permits the definition of tail-recursive functions without the
   916 provision of a termination measure. The latter is necessary once the
   917 invariant proof rule for while is applied.
   918 
   919 * HOL: new (overloaded) notation for the set of elements below/above
   920 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   921 
   922 * HOL: theorems impI, allI, ballI bound as "strip";
   923 
   924 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   925 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   926 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   927 
   928 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   929 
   930 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   931 main HOL, but was unused);
   932 
   933 * HOL: fewer consts declared as global (e.g. have to refer to
   934 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   935 
   936 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   937 in case of overlap with user translations (e.g. judgements over
   938 tuples); (note that the underlying logical represenation is still
   939 bogus);
   940 
   941 
   942 *** ZF ***
   943 
   944 * ZF: simplification automatically cancels common terms in arithmetic
   945 expressions over nat and int;
   946 
   947 * ZF: new treatment of nat to minimize type-checking: all operators
   948 coerce their operands to a natural number using the function natify,
   949 making the algebraic laws unconditional;
   950 
   951 * ZF: as above, for int: operators coerce their operands to an integer
   952 using the function intify;
   953 
   954 * ZF: the integer library now contains many of the usual laws for the
   955 orderings, including $<=, and monotonicity laws for $+ and $*;
   956 
   957 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   958 simplification;
   959 
   960 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   961 to the simplifier and classical reasoner simultaneously;
   962 
   963 
   964 *** General ***
   965 
   966 * Provers: blast_tac now handles actual object-logic rules as
   967 assumptions; note that auto_tac uses blast_tac internally as well;
   968 
   969 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   970 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   971 
   972 * Provers: delrules now handles destruct rules as well (no longer need
   973 explicit make_elim);
   974 
   975 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   976   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   977 use instead the strong form,
   978   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   979 in HOL, FOL and ZF the function cla_make_elim will create such rules
   980 from destruct-rules;
   981 
   982 * Provers: Simplifier.easy_setup provides a fast path to basic
   983 Simplifier setup for new object-logics;
   984 
   985 * Pure: AST translation rules no longer require constant head on LHS;
   986 
   987 * Pure: improved name spaces: ambiguous output is qualified; support
   988 for hiding of names;
   989 
   990 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   991 XSYMBOL_HOME; no longer need to do manual configuration in most
   992 situations;
   993 
   994 * system: compression of ML heaps images may now be controlled via -c
   995 option of isabelle and isatool usedir (currently only observed by
   996 Poly/ML);
   997 
   998 * system: isatool installfonts may handle X-Symbol fonts as well (very
   999 useful for remote X11);
  1000 
  1001 * system: provide TAGS file for Isabelle sources;
  1002 
  1003 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1004 order;
  1005 
  1006 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1007 timing flag supersedes proof_timing and Toplevel.trace;
  1008 
  1009 * ML: new combinators |>> and |>>> for incremental transformations
  1010 with secondary results (e.g. certain theory extensions):
  1011 
  1012 * ML: PureThy.add_defs gets additional argument to indicate potential
  1013 overloading (usually false);
  1014 
  1015 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1016 results;
  1017 
  1018 
  1019 
  1020 New in Isabelle99 (October 1999)
  1021 --------------------------------
  1022 
  1023 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1024 
  1025 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1026 are no longer simplified.  (This allows the simplifier to unfold recursive
  1027 functional programs.)  To restore the old behaviour, declare
  1028 
  1029     Delcongs [if_weak_cong];
  1030 
  1031 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1032 complement;
  1033 
  1034 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1035 
  1036 * HOL/datatype: mutual_induct_tac no longer exists --
  1037   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1038 
  1039 * HOL/typedef: fixed type inference for representing set; type
  1040 arguments now have to occur explicitly on the rhs as type constraints;
  1041 
  1042 * ZF: The con_defs part of an inductive definition may no longer refer
  1043 to constants declared in the same theory;
  1044 
  1045 * HOL, ZF: the function mk_cases, generated by the inductive
  1046 definition package, has lost an argument.  To simplify its result, it
  1047 uses the default simpset instead of a supplied list of theorems.
  1048 
  1049 * HOL/List: the constructors of type list are now Nil and Cons;
  1050 
  1051 * Simplifier: the type of the infix ML functions
  1052         setSSolver addSSolver setSolver addSolver
  1053 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1054 for packaging solvers. A solver is created via
  1055         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1056 where the string argument is only a comment.
  1057 
  1058 
  1059 *** Proof tools ***
  1060 
  1061 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1062 decision procedure for linear arithmetic. Currently it is used for
  1063 types `nat', `int', and `real' in HOL (see below); it can, should and
  1064 will be instantiated for other types and logics as well.
  1065 
  1066 * The simplifier now accepts rewrite rules with flexible heads, eg
  1067      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1068   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1069   matching.
  1070 
  1071 
  1072 *** General ***
  1073 
  1074 * New Isabelle/Isar subsystem provides an alternative to traditional
  1075 tactical theorem proving; together with the ProofGeneral/isar user
  1076 interface it offers an interactive environment for developing human
  1077 readable proof documents (Isar == Intelligible semi-automated
  1078 reasoning); for further information see isatool doc isar-ref,
  1079 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1080 
  1081 * improved and simplified presentation of theories: better HTML markup
  1082 (including colors), graph views in several sizes; isatool usedir now
  1083 provides a proper interface for user theories (via -P option); actual
  1084 document preparation based on (PDF)LaTeX is available as well (for
  1085 new-style theories only); see isatool doc system for more information;
  1086 
  1087 * native support for Proof General, both for classic Isabelle and
  1088 Isabelle/Isar;
  1089 
  1090 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1091 using the graph browser tool;
  1092 
  1093 * Isabelle manuals now also available as PDF;
  1094 
  1095 * theory loader rewritten from scratch (may not be fully
  1096 bug-compatible); old loadpath variable has been replaced by show_path,
  1097 add_path, del_path, reset_path functions; new operations such as
  1098 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1099 isatool doc ref);
  1100 
  1101 * improved isatool install: option -k creates KDE application icon,
  1102 option -p DIR installs standalone binaries;
  1103 
  1104 * added ML_PLATFORM setting (useful for cross-platform installations);
  1105 more robust handling of platform specific ML images for SML/NJ;
  1106 
  1107 * the settings environment is now statically scoped, i.e. it is never
  1108 created again in sub-processes invoked from isabelle, isatool, or
  1109 Isabelle;
  1110 
  1111 * path element specification '~~' refers to '$ISABELLE_HOME';
  1112 
  1113 * in locales, the "assumes" and "defines" parts may be omitted if
  1114 empty;
  1115 
  1116 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1117 long arrows);
  1118 
  1119 * new print_mode "HTML";
  1120 
  1121 * new flag show_tags controls display of tags of theorems (which are
  1122 basically just comments that may be attached by some tools);
  1123 
  1124 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1125 mode and goal output format:
  1126 
  1127 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1128 244c244
  1129 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1130 ---
  1131 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1132 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1133 181c181
  1134 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1135 ---
  1136 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1137 
  1138 * function bind_thms stores lists of theorems (cf. bind_thm);
  1139 
  1140 * new shorthand tactics ftac, eatac, datac, fatac;
  1141 
  1142 * qed (and friends) now accept "" as result name; in that case the
  1143 theorem is not stored, but proper checks and presentation of the
  1144 result still apply;
  1145 
  1146 * theorem database now also indexes constants "Trueprop", "all",
  1147 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1148 
  1149 
  1150 *** HOL ***
  1151 
  1152 ** HOL arithmetic **
  1153 
  1154 * There are now decision procedures for linear arithmetic over nat and
  1155 int:
  1156 
  1157 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1158 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1159 are treated as atomic; subformulae not involving type `nat' or `int'
  1160 are ignored; quantified subformulae are ignored unless they are
  1161 positive universal or negative existential. The tactic has to be
  1162 invoked by hand and can be a little bit slow. In particular, the
  1163 running time is exponential in the number of occurrences of `min' and
  1164 `max', and `-' on `nat'.
  1165 
  1166 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1167 (negated) (in)equalities among the premises and the conclusion into
  1168 account (i.e. no compound formulae) and does not know about `min' and
  1169 `max', and `-' on `nat'. It is fast and is used automatically by the
  1170 simplifier.
  1171 
  1172 NB: At the moment, these decision procedures do not cope with mixed
  1173 nat/int formulae where the two parts interact, such as `m < n ==>
  1174 int(m) < int(n)'.
  1175 
  1176 * HOL/Numeral provides a generic theory of numerals (encoded
  1177 efficiently as bit strings); setup for types nat/int/real is in place;
  1178 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1179 int, existing theories and proof scripts may require a few additional
  1180 type constraints;
  1181 
  1182 * integer division and remainder can now be performed on constant
  1183 arguments;
  1184 
  1185 * many properties of integer multiplication, division and remainder
  1186 are now available;
  1187 
  1188 * An interface to the Stanford Validity Checker (SVC) is available through the
  1189 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1190 are proved automatically.  SVC must be installed separately, and its results
  1191 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1192 invocation of the underlying oracle).  For SVC see
  1193   http://verify.stanford.edu/SVC
  1194 
  1195 * IsaMakefile: the HOL-Real target now builds an actual image;
  1196 
  1197 
  1198 ** HOL misc **
  1199 
  1200 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1201 (in Isabelle/Isar) -- by Gertrud Bauer;
  1202 
  1203 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1204 analysis for assembly languages with subtypes;
  1205 
  1206 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1207 -- avoids syntactic ambiguities and treats state, transition, and
  1208 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1209 changed syntax and (many) tactics;
  1210 
  1211 * HOL/inductive: Now also handles more general introduction rules such
  1212   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1213   theorems are now maintained within the theory (maintained via the
  1214   "mono" attribute);
  1215 
  1216 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1217   (using function types) such as
  1218 
  1219   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1220 
  1221 * HOL/record: record_simproc (part of the default simpset) takes care
  1222 of selectors applied to updated records; record_split_tac is no longer
  1223 part of the default claset; update_defs may now be removed from the
  1224 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1225 
  1226   claset_ref () := claset() addSWrapper record_split_wrapper;
  1227   Delsimprocs [record_simproc]
  1228 
  1229 * HOL/typedef: fixed type inference for representing set; type
  1230 arguments now have to occur explicitly on the rhs as type constraints;
  1231 
  1232 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1233 names rather than an ML expression;
  1234 
  1235 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1236 supplied later.  Program schemes can be defined, such as
  1237     "While B C s = (if B s then While B C (C s) else s)"
  1238 where the well-founded relation can be chosen after B and C have been given.
  1239 
  1240 * HOL/List: the constructors of type list are now Nil and Cons;
  1241 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1242 course, ML tools referring to List.list.op # etc. have to be adapted;
  1243 
  1244 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1245 disabled by default; run isabelle with option -m HOL to get back to
  1246 the original Gordon/HOL-style output;
  1247 
  1248 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1249 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1250 
  1251 * HOL basic syntax simplified (more orthogonal): all variants of
  1252 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1253 Eps operator is provided as well: "SOME x. P[x]";
  1254 
  1255 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1256 
  1257 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1258 thus available for user theories;
  1259 
  1260 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1261 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1262 time;
  1263 
  1264 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1265 several times and then mp;
  1266 
  1267 
  1268 *** LK ***
  1269 
  1270 * the notation <<...>> is now available as a notation for sequences of
  1271 formulas;
  1272 
  1273 * the simplifier is now installed
  1274 
  1275 * the axiom system has been generalized (thanks to Soren Heilmann)
  1276 
  1277 * the classical reasoner now has a default rule database
  1278 
  1279 
  1280 *** ZF ***
  1281 
  1282 * new primrec section allows primitive recursive functions to be given
  1283 directly (as in HOL) over datatypes and the natural numbers;
  1284 
  1285 * new tactics induct_tac and exhaust_tac for induction (or case
  1286 analysis) over datatypes and the natural numbers;
  1287 
  1288 * the datatype declaration of type T now defines the recursor T_rec;
  1289 
  1290 * simplification automatically does freeness reasoning for datatype
  1291 constructors;
  1292 
  1293 * automatic type-inference, with AddTCs command to insert new
  1294 type-checking rules;
  1295 
  1296 * datatype introduction rules are now added as Safe Introduction rules
  1297 to the claset;
  1298 
  1299 * the syntax "if P then x else y" is now available in addition to
  1300 if(P,x,y);
  1301 
  1302 
  1303 *** Internal programming interfaces ***
  1304 
  1305 * tuned simplifier trace output; new flag debug_simp;
  1306 
  1307 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1308 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1309 
  1310 * AxClass.axclass_tac lost the theory argument;
  1311 
  1312 * tuned current_goals_markers semantics: begin / end goal avoids
  1313 printing empty lines;
  1314 
  1315 * removed prs and prs_fn hook, which was broken because it did not
  1316 include \n in its semantics, forcing writeln to add one
  1317 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1318 string -> unit if you really want to output text without newline;
  1319 
  1320 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1321 plain output, interface builders may have to enable 'isabelle_font'
  1322 mode to get Isabelle font glyphs as before;
  1323 
  1324 * refined token_translation interface; INCOMPATIBILITY: output length
  1325 now of type real instead of int;
  1326 
  1327 * theory loader actions may be traced via new ThyInfo.add_hook
  1328 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1329 your own database of information attached to *whole* theories -- as
  1330 opposed to intra-theory data slots offered via TheoryDataFun;
  1331 
  1332 * proper handling of dangling sort hypotheses (at last!);
  1333 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1334 extra sort hypotheses that can be witnessed from the type signature;
  1335 the force_strip_shyps flag is gone, any remaining shyps are simply
  1336 left in the theorem (with a warning issued by strip_shyps_warning);
  1337 
  1338 
  1339 
  1340 New in Isabelle98-1 (October 1998)
  1341 ----------------------------------
  1342 
  1343 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1344 
  1345 * several changes of automated proof tools;
  1346 
  1347 * HOL: major changes to the inductive and datatype packages, including
  1348 some minor incompatibilities of theory syntax;
  1349 
  1350 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1351 called `inj_on';
  1352 
  1353 * HOL: removed duplicate thms in Arith:
  1354   less_imp_add_less  should be replaced by  trans_less_add1
  1355   le_imp_add_le      should be replaced by  trans_le_add1
  1356 
  1357 * HOL: unary minus is now overloaded (new type constraints may be
  1358 required);
  1359 
  1360 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1361 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1362 now taken as an integer constant.
  1363 
  1364 * Pure: ML function 'theory_of' renamed to 'theory';
  1365 
  1366 
  1367 *** Proof tools ***
  1368 
  1369 * Simplifier:
  1370   1. Asm_full_simp_tac is now more aggressive.
  1371      1. It will sometimes reorient premises if that increases their power to
  1372         simplify.
  1373      2. It does no longer proceed strictly from left to right but may also
  1374         rotate premises to achieve further simplification.
  1375      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1376      old Asm_full_simp_tac in that it does not rotate premises.
  1377   2. The simplifier now knows a little bit about nat-arithmetic.
  1378 
  1379 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1380 allows for selected deletion of wrappers, by introduction of names for
  1381 wrapper functionals.  This implies that addbefore, addSbefore,
  1382 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1383 and that adding two tactics with the same name overwrites the first
  1384 one (emitting a warning).
  1385   type wrapper = (int -> tactic) -> (int -> tactic)
  1386   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1387   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1388   delWrapper, delSWrapper: claset *  string            -> claset
  1389   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1390 
  1391 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1392 semantics; addbefore now affects only the unsafe part of step_tac
  1393 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1394 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1395 by Force_tac;
  1396 
  1397 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1398 compWrapper; added safe wrapper (and access functions for it);
  1399 
  1400 * HOL/split_all_tac is now much faster and fails if there is nothing
  1401 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1402 and the names of the automatically generated variables have changed.
  1403 split_all_tac has moved within claset() from unsafe wrappers to safe
  1404 wrappers, which means that !!-bound variables are split much more
  1405 aggressively, and safe_tac and clarify_tac now split such variables.
  1406 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1407 Note: the same holds for record_split_tac, which does the job of
  1408 split_all_tac for record fields.
  1409 
  1410 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1411 permanently to the default simpset using Addsplits just like
  1412 Addsimps. They can be removed via Delsplits just like
  1413 Delsimps. Lower-case versions are also available.
  1414 
  1415 * HOL/Simplifier: The rule split_if is now part of the default
  1416 simpset. This means that the simplifier will eliminate all occurrences
  1417 of if-then-else in the conclusion of a goal. To prevent this, you can
  1418 either remove split_if completely from the default simpset by
  1419 `Delsplits [split_if]' or remove it in a specific call of the
  1420 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1421 other case splitting rules to/from the default simpset: every datatype
  1422 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1423 t is the name of the datatype).
  1424 
  1425 * Classical reasoner / Simplifier combination: new force_tac (and
  1426 derivatives Force_tac, force) combines rewriting and classical
  1427 reasoning (and whatever other tools) similarly to auto_tac, but is
  1428 aimed to solve the given subgoal completely.
  1429 
  1430 
  1431 *** General ***
  1432 
  1433 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1434 and `goalw': the theory is no longer needed as an explicit argument -
  1435 the current theory context is used; assumptions are no longer returned
  1436 at the ML-level unless one of them starts with ==> or !!; it is
  1437 recommended to convert to these new commands using isatool fixgoal
  1438 (backup your sources first!);
  1439 
  1440 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1441 the current theory context, and 'theory' to lookup stored theories;
  1442 
  1443 * new theory section 'locale' for declaring constants, assumptions and
  1444 definitions that have local scope;
  1445 
  1446 * new theory section 'nonterminals' for purely syntactic types;
  1447 
  1448 * new theory section 'setup' for generic ML setup functions
  1449 (e.g. package initialization);
  1450 
  1451 * the distribution now includes Isabelle icons: see
  1452 lib/logo/isabelle-{small,tiny}.xpm;
  1453 
  1454 * isatool install - install binaries with absolute references to
  1455 ISABELLE_HOME/bin;
  1456 
  1457 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1458 
  1459 * print mode 'emacs' reserved for Isamode;
  1460 
  1461 * support multiple print (ast) translations per constant name;
  1462 
  1463 * theorems involving oracles are now printed with a suffixed [!];
  1464 
  1465 
  1466 *** HOL ***
  1467 
  1468 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1469 
  1470 * HOL/inductive package reorganized and improved: now supports mutual
  1471 definitions such as
  1472 
  1473   inductive EVEN ODD
  1474     intrs
  1475       null "0 : EVEN"
  1476       oddI "n : EVEN ==> Suc n : ODD"
  1477       evenI "n : ODD ==> Suc n : EVEN"
  1478 
  1479 new theorem list "elims" contains an elimination rule for each of the
  1480 recursive sets; inductive definitions now handle disjunctive premises
  1481 correctly (also ZF);
  1482 
  1483 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1484 "mutual_induct" no longer exists - the induction rule is always
  1485 contained in "induct";
  1486 
  1487 
  1488 * HOL/datatype package re-implemented and greatly improved: now
  1489 supports mutually recursive datatypes such as
  1490 
  1491   datatype
  1492     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1493             | SUM ('a aexp) ('a aexp)
  1494             | DIFF ('a aexp) ('a aexp)
  1495             | NUM 'a
  1496   and
  1497     'a bexp = LESS ('a aexp) ('a aexp)
  1498             | AND ('a bexp) ('a bexp)
  1499             | OR ('a bexp) ('a bexp)
  1500 
  1501 as well as indirectly recursive datatypes such as
  1502 
  1503   datatype
  1504     ('a, 'b) term = Var 'a
  1505                   | App 'b ((('a, 'b) term) list)
  1506 
  1507 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1508 induction on mutually / indirectly recursive datatypes.
  1509 
  1510 Primrec equations are now stored in theory and can be accessed via
  1511 <function_name>.simps.
  1512 
  1513 INCOMPATIBILITIES:
  1514 
  1515   - Theories using datatypes must now have theory Datatype as an
  1516     ancestor.
  1517   - The specific <typename>.induct_tac no longer exists - use the
  1518     generic induct_tac instead.
  1519   - natE has been renamed to nat.exhaust - use exhaust_tac
  1520     instead of res_inst_tac ... natE. Note that the variable
  1521     names in nat.exhaust differ from the names in natE, this
  1522     may cause some "fragile" proofs to fail.
  1523   - The theorems split_<typename>_case and split_<typename>_case_asm
  1524     have been renamed to <typename>.split and <typename>.split_asm.
  1525   - Since default sorts of type variables are now handled correctly,
  1526     some datatype definitions may have to be annotated with explicit
  1527     sort constraints.
  1528   - Primrec definitions no longer require function name and type
  1529     of recursive argument.
  1530 
  1531 Consider using isatool fixdatatype to adapt your theories and proof
  1532 scripts to the new package (backup your sources first!).
  1533 
  1534 
  1535 * HOL/record package: considerably improved implementation; now
  1536 includes concrete syntax for record types, terms, updates; theorems
  1537 for surjective pairing and splitting !!-bound record variables; proof
  1538 support is as follows:
  1539 
  1540   1) standard conversions (selectors or updates applied to record
  1541 constructor terms) are part of the standard simpset;
  1542 
  1543   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1544 made part of standard simpset and claset via addIffs;
  1545 
  1546   3) a tactic for record field splitting (record_split_tac) is part of
  1547 the standard claset (addSWrapper);
  1548 
  1549 To get a better idea about these rules you may retrieve them via
  1550 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1551 the name of your record type.
  1552 
  1553 The split tactic 3) conceptually simplifies by the following rule:
  1554 
  1555   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1556 
  1557 Thus any record variable that is bound by meta-all will automatically
  1558 blow up into some record constructor term, consequently the
  1559 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1560 solve record problems automatically.
  1561 
  1562 
  1563 * reorganized the main HOL image: HOL/Integ and String loaded by
  1564 default; theory Main includes everything;
  1565 
  1566 * automatic simplification of integer sums and comparisons, using cancellation;
  1567 
  1568 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1569 
  1570 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1571 
  1572 * many new identities for unions, intersections, set difference, etc.;
  1573 
  1574 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1575 called split_if, split_split, split_sum_case and split_nat_case (to go
  1576 with add/delsplits);
  1577 
  1578 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1579 (?x::unit) = (); this is made part of the default simpset, which COULD
  1580 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1581 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1582 unit_abs_eta_conv is added in order to counter the effect of
  1583 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1584 %u.f();
  1585 
  1586 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1587 makes more sense);
  1588 
  1589 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1590   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1591   disjointness reasoning but breaking a few old proofs.
  1592 
  1593 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1594 to 'converse' from 'inverse' (for compatibility with ZF and some
  1595 literature);
  1596 
  1597 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1598 the well-founded relation;
  1599 
  1600 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1601     Compl A.  The "Compl" syntax remains available as input syntax for this
  1602     release ONLY.
  1603 
  1604 * HOL/Update: new theory of function updates:
  1605     f(a:=b) == %x. if x=a then b else f x
  1606 may also be iterated as in f(a:=b,c:=d,...);
  1607 
  1608 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1609 
  1610 * HOL/List:
  1611   - new function list_update written xs[i:=v] that updates the i-th
  1612     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1613   - new function `upt' written [i..j(] which generates the list
  1614     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1615     bound write [i..j], which is a shorthand for [i..j+1(].
  1616   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1617 
  1618 * HOL/Arith:
  1619   - removed 'pred' (predecessor) function;
  1620   - generalized some theorems about n-1;
  1621   - many new laws about "div" and "mod";
  1622   - new laws about greatest common divisors (see theory ex/Primes);
  1623 
  1624 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1625 instead of "inverse";
  1626 
  1627 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1628   of the multiset ordering;
  1629 
  1630 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1631   (not included by default);
  1632 
  1633 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1634 
  1635 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1636   programs, i.e. different program variables may have different types.
  1637 
  1638 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1639   [previously, this check worked only if the rewrite rule was unconditional]
  1640   Now rew can involve either definitions or equalities (either == or =).
  1641 
  1642 
  1643 *** ZF ***
  1644 
  1645 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1646   only the theorems proved on ZF.ML;
  1647 
  1648 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1649   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1650   disjointness reasoning but breaking a few old proofs.
  1651 
  1652 * ZF/Update: new theory of function updates
  1653     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1654   may also be iterated as in f(a:=b,c:=d,...);
  1655 
  1656 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1657 
  1658 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1659   [previously, this check worked only if the rewrite rule was unconditional]
  1660   Now rew can involve either definitions or equalities (either == or =).
  1661 
  1662 * case_tac provided for compatibility with HOL
  1663     (like the old excluded_middle_tac, but with subgoals swapped)
  1664 
  1665 
  1666 *** Internal programming interfaces ***
  1667 
  1668 * Pure: several new basic modules made available for general use, see
  1669 also src/Pure/README;
  1670 
  1671 * improved the theory data mechanism to support encapsulation (data
  1672 kind name replaced by private Object.kind, acting as authorization
  1673 key); new type-safe user interface via functor TheoryDataFun; generic
  1674 print_data function becomes basically useless;
  1675 
  1676 * removed global_names compatibility flag -- all theory declarations
  1677 are qualified by default;
  1678 
  1679 * module Pure/Syntax now offers quote / antiquote translation
  1680 functions (useful for Hoare logic etc. with implicit dependencies);
  1681 see HOL/ex/Antiquote for an example use;
  1682 
  1683 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1684 cterm -> thm;
  1685 
  1686 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1687 subgoal;
  1688 
  1689 * Display.print_goals function moved to Locale.print_goals;
  1690 
  1691 * standard print function for goals supports current_goals_markers
  1692 variable for marking begin of proof, end of proof, start of goal; the
  1693 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1694 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1695 for example;
  1696 
  1697 
  1698 
  1699 New in Isabelle98 (January 1998)
  1700 --------------------------------
  1701 
  1702 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1703 
  1704 * changed lexical syntax of terms / types: dots made part of long
  1705 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1706 
  1707 * simpset (and claset) reference variable replaced by functions
  1708 simpset / simpset_ref;
  1709 
  1710 * no longer supports theory aliases (via merge) and non-trivial
  1711 implicit merge of thms' signatures;
  1712 
  1713 * most internal names of constants changed due to qualified names;
  1714 
  1715 * changed Pure/Sequence interface (see Pure/seq.ML);
  1716 
  1717 
  1718 *** General Changes ***
  1719 
  1720 * hierachically structured name spaces (for consts, types, axms, thms
  1721 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1722 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1723 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1724 long_names for fully qualified output names; NOTE: ML programs
  1725 (special tactics, packages etc.) referring to internal names may have
  1726 to be adapted to cope with fully qualified names; in case of severe
  1727 backward campatibility problems try setting 'global_names' at compile
  1728 time to have enrything declared within a flat name space; one may also
  1729 fine tune name declarations in theories via the 'global' and 'local'
  1730 section;
  1731 
  1732 * reimplemented the implicit simpset and claset using the new anytype
  1733 data filed in signatures; references simpset:simpset ref etc. are
  1734 replaced by functions simpset:unit->simpset and
  1735 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1736 to patch your ML files accordingly;
  1737 
  1738 * HTML output now includes theory graph data for display with Java
  1739 applet or isatool browser; data generated automatically via isatool
  1740 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1741 
  1742 * defs may now be conditional; improved rewrite_goals_tac to handle
  1743 conditional equations;
  1744 
  1745 * defs now admits additional type arguments, using TYPE('a) syntax;
  1746 
  1747 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1748 creates a new theory node; implicit merge of thms' signatures is
  1749 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1750 transfer:theory->thm->thm in (rare) cases;
  1751 
  1752 * improved handling of draft signatures / theories; draft thms (and
  1753 ctyps, cterms) are automatically promoted to real ones;
  1754 
  1755 * slightly changed interfaces for oracles: admit many per theory, named
  1756 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1757 
  1758 * print_goals: optional output of const types (set show_consts and
  1759 show_types);
  1760 
  1761 * improved output of warnings (###) and errors (***);
  1762 
  1763 * subgoal_tac displays a warning if the new subgoal has type variables;
  1764 
  1765 * removed old README and Makefiles;
  1766 
  1767 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1768 
  1769 * removed obsolete init_pps and init_database;
  1770 
  1771 * deleted the obsolete tactical STATE, which was declared by
  1772     fun STATE tacfun st = tacfun st st;
  1773 
  1774 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1775 (which abbreviates $HOME);
  1776 
  1777 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1778 use isatool fixseq to adapt your ML programs (this works for fully
  1779 qualified references to the Sequence structure only!);
  1780 
  1781 * use_thy no longer requires writable current directory; it always
  1782 reloads .ML *and* .thy file, if either one is out of date;
  1783 
  1784 
  1785 *** Classical Reasoner ***
  1786 
  1787 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1788 tactics that use classical reasoning to simplify a subgoal without
  1789 splitting it into several subgoals;
  1790 
  1791 * Safe_tac: like safe_tac but uses the default claset;
  1792 
  1793 
  1794 *** Simplifier ***
  1795 
  1796 * added simplification meta rules:
  1797     (asm_)(full_)simplify: simpset -> thm -> thm;
  1798 
  1799 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1800 logics (again);
  1801 
  1802 * added prems argument to simplification procedures;
  1803 
  1804 * HOL, FOL, ZF: added infix function `addsplits':
  1805   instead of `<simpset> setloop (split_tac <thms>)'
  1806   you can simply write `<simpset> addsplits <thms>'
  1807 
  1808 
  1809 *** Syntax ***
  1810 
  1811 * TYPE('a) syntax for type reflection terms;
  1812 
  1813 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1814 
  1815 * pretty printer: changed order of mixfix annotation preference (again!);
  1816 
  1817 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1818 
  1819 
  1820 *** HOL ***
  1821 
  1822 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1823   with `addloop' of the simplifier to faciliate case splitting in premises.
  1824 
  1825 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1826 
  1827 * HOL/Auth: new protocol proofs including some for the Internet
  1828   protocol TLS;
  1829 
  1830 * HOL/Map: new theory of `maps' a la VDM;
  1831 
  1832 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1833 cancelling out common nat summands from =, <, <= (in)equalities, or
  1834 differences; simplification procedures nat_cancel_factor for
  1835 cancelling common factor from =, <, <= (in)equalities over natural
  1836 sums; nat_cancel contains both kinds of procedures, it is installed by
  1837 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1838 
  1839 * HOL/simplifier: terms of the form
  1840   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1841   are rewritten to
  1842   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1843   and those of the form
  1844   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1845   are rewritten to
  1846   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1847 
  1848 * HOL/datatype
  1849   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1850 
  1851   P(t_case f1 ... fn x) =
  1852      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1853         ...
  1854        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1855      )
  1856 
  1857   and a theorem `split_t_case_asm' of the form
  1858 
  1859   P(t_case f1 ... fn x) =
  1860     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1861         ...
  1862        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1863      )
  1864   which can be added to a simpset via `addsplits'. The existing theorems
  1865   expand_list_case and expand_option_case have been renamed to
  1866   split_list_case and split_option_case.
  1867 
  1868 * HOL/Arithmetic:
  1869   - `pred n' is automatically converted to `n-1'.
  1870     Users are strongly encouraged not to use `pred' any longer,
  1871     because it will disappear altogether at some point.
  1872   - Users are strongly encouraged to write "0 < n" rather than
  1873     "n ~= 0". Theorems and proof tools have been modified towards this
  1874     `standard'.
  1875 
  1876 * HOL/Lists:
  1877   the function "set_of_list" has been renamed "set" (and its theorems too);
  1878   the function "nth" now takes its arguments in the reverse order and
  1879   has acquired the infix notation "!" as in "xs!n".
  1880 
  1881 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1882 
  1883 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1884   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1885 
  1886 * HOL/record: extensible records with schematic structural subtyping
  1887 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1888 still lacks various theorems and concrete record syntax;
  1889 
  1890 
  1891 *** HOLCF ***
  1892 
  1893 * removed "axioms" and "generated by" sections;
  1894 
  1895 * replaced "ops" section by extended "consts" section, which is capable of
  1896   handling the continuous function space "->" directly;
  1897 
  1898 * domain package:
  1899   . proves theorems immediately and stores them in the theory,
  1900   . creates hierachical name space,
  1901   . now uses normal mixfix annotations (instead of cinfix...),
  1902   . minor changes to some names and values (for consistency),
  1903   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1904   . separator between mutual domain defs: changed "," to "and",
  1905   . improved handling of sort constraints;  now they have to
  1906     appear on the left-hand side of the equations only;
  1907 
  1908 * fixed LAM <x,y,zs>.b syntax;
  1909 
  1910 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1911 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1912 
  1913 
  1914 *** FOL and ZF ***
  1915 
  1916 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1917   with `addloop' of the simplifier to faciliate case splitting in premises.
  1918 
  1919 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1920 in HOL, they strip ALL and --> from proved theorems;
  1921 
  1922 
  1923 
  1924 New in Isabelle94-8 (May 1997)
  1925 ------------------------------
  1926 
  1927 *** General Changes ***
  1928 
  1929 * new utilities to build / run / maintain Isabelle etc. (in parts
  1930 still somewhat experimental); old Makefiles etc. still functional;
  1931 
  1932 * new 'Isabelle System Manual';
  1933 
  1934 * INSTALL text, together with ./configure and ./build scripts;
  1935 
  1936 * reimplemented type inference for greater efficiency, better error
  1937 messages and clean internal interface;
  1938 
  1939 * prlim command for dealing with lots of subgoals (an easier way of
  1940 setting goals_limit);
  1941 
  1942 
  1943 *** Syntax ***
  1944 
  1945 * supports alternative (named) syntax tables (parser and pretty
  1946 printer); internal interface is provided by add_modesyntax(_i);
  1947 
  1948 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1949 be used in conjunction with the Isabelle symbol font; uses the
  1950 "symbols" syntax table;
  1951 
  1952 * added token_translation interface (may translate name tokens in
  1953 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1954 the current print_mode); IMPORTANT: user print translation functions
  1955 are responsible for marking newly introduced bounds
  1956 (Syntax.mark_boundT);
  1957 
  1958 * token translations for modes "xterm" and "xterm_color" that display
  1959 names in bold, underline etc. or colors (which requires a color
  1960 version of xterm);
  1961 
  1962 * infixes may now be declared with names independent of their syntax;
  1963 
  1964 * added typed_print_translation (like print_translation, but may
  1965 access type of constant);
  1966 
  1967 
  1968 *** Classical Reasoner ***
  1969 
  1970 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1971 some limitations.  Blast_tac...
  1972   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1973   + ignores elimination rules that don't have the correct format
  1974         (the conclusion MUST be a formula variable)
  1975   + ignores types, which can make HOL proofs fail
  1976   + rules must not require higher-order unification, e.g. apply_type in ZF
  1977     [message "Function Var's argument not a bound variable" relates to this]
  1978   + its proof strategy is more general but can actually be slower
  1979 
  1980 * substitution with equality assumptions no longer permutes other
  1981 assumptions;
  1982 
  1983 * minor changes in semantics of addafter (now called addaltern); renamed
  1984 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1985 (and access functions for it);
  1986 
  1987 * improved combination of classical reasoner and simplifier:
  1988   + functions for handling clasimpsets
  1989   + improvement of addss: now the simplifier is called _after_ the
  1990     safe steps.
  1991   + safe variant of addss called addSss: uses safe simplifications
  1992     _during_ the safe steps. It is more complete as it allows multiple
  1993     instantiations of unknowns (e.g. with slow_tac).
  1994 
  1995 *** Simplifier ***
  1996 
  1997 * added interface for simplification procedures (functions that
  1998 produce *proven* rewrite rules on the fly, depending on current
  1999 redex);
  2000 
  2001 * ordering on terms as parameter (used for ordered rewriting);
  2002 
  2003 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2004 
  2005 * the solver is now split into a safe and an unsafe part.
  2006 This should be invisible for the normal user, except that the
  2007 functions setsolver and addsolver have been renamed to setSolver and
  2008 addSolver; added safe_asm_full_simp_tac;
  2009 
  2010 
  2011 *** HOL ***
  2012 
  2013 * a generic induction tactic `induct_tac' which works for all datatypes and
  2014 also for type `nat';
  2015 
  2016 * a generic case distinction tactic `exhaust_tac' which works for all
  2017 datatypes and also for type `nat';
  2018 
  2019 * each datatype comes with a function `size';
  2020 
  2021 * patterns in case expressions allow tuple patterns as arguments to
  2022 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2023 
  2024 * primrec now also works with type nat;
  2025 
  2026 * recdef: a new declaration form, allows general recursive functions to be
  2027 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2028 
  2029 * the constant for negation has been renamed from "not" to "Not" to
  2030 harmonize with FOL, ZF, LK, etc.;
  2031 
  2032 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2033 infinite lists;
  2034 
  2035 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2036 
  2037 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2038 problems in commutative rings, using axiomatic type classes for + and *;
  2039 
  2040 * more examples in HOL/MiniML and HOL/Auth;
  2041 
  2042 * more default rewrite rules for quantifiers, union/intersection;
  2043 
  2044 * a new constant `arbitrary == @x.False';
  2045 
  2046 * HOLCF/IOA replaces old HOL/IOA;
  2047 
  2048 * HOLCF changes: derived all rules and arities
  2049   + axiomatic type classes instead of classes
  2050   + typedef instead of faking type definitions
  2051   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2052   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2053   + eliminated the types void, one, tr
  2054   + use unit lift and bool lift (with translations) instead of one and tr
  2055   + eliminated blift from Lift3.thy (use Def instead of blift)
  2056   all eliminated rules are derived as theorems --> no visible changes ;
  2057 
  2058 
  2059 *** ZF ***
  2060 
  2061 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2062 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2063 as ZF_cs addSIs [equalityI];
  2064 
  2065 
  2066 
  2067 New in Isabelle94-7 (November 96)
  2068 ---------------------------------
  2069 
  2070 * allowing negative levels (as offsets) in prlev and choplev;
  2071 
  2072 * super-linear speedup for large simplifications;
  2073 
  2074 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2075 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2076 FAIL); can suppress it using the command Delsimps (ex_simps @
  2077 all_simps); De Morgan laws are also now included, by default;
  2078 
  2079 * improved printing of ==>  :  ~:
  2080 
  2081 * new object-logic "Sequents" adds linear logic, while replacing LK
  2082 and Modal (thanks to Sara Kalvala);
  2083 
  2084 * HOL/Auth: correctness proofs for authentication protocols;
  2085 
  2086 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2087 examples on HOL/Auth);
  2088 
  2089 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2090 the rewriter and classical reasoner simultaneously;
  2091 
  2092 * function uresult no longer returns theorems in "standard" format;
  2093 regain previous version by: val uresult = standard o uresult;
  2094 
  2095 
  2096 
  2097 New in Isabelle94-6
  2098 -------------------
  2099 
  2100 * oracles -- these establish an interface between Isabelle and trusted
  2101 external reasoners, which may deliver results as theorems;
  2102 
  2103 * proof objects (in particular record all uses of oracles);
  2104 
  2105 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2106 
  2107 * "constdefs" section in theory files;
  2108 
  2109 * "primrec" section (HOL) no longer requires names;
  2110 
  2111 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2112 
  2113 
  2114 
  2115 New in Isabelle94-5
  2116 -------------------
  2117 
  2118 * reduced space requirements;
  2119 
  2120 * automatic HTML generation from theories;
  2121 
  2122 * theory files no longer require "..." (quotes) around most types;
  2123 
  2124 * new examples, including two proofs of the Church-Rosser theorem;
  2125 
  2126 * non-curried (1994) version of HOL is no longer distributed;
  2127 
  2128 
  2129 
  2130 New in Isabelle94-4
  2131 -------------------
  2132 
  2133 * greatly reduced space requirements;
  2134 
  2135 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2136 
  2137 * searchable theorem database (see the section "Retrieving theorems" on
  2138 page 8 of the Reference Manual);
  2139 
  2140 * new examples, including Grabczewski's monumental case study of the
  2141 Axiom of Choice;
  2142 
  2143 * The previous version of HOL renamed to Old_HOL;
  2144 
  2145 * The new version of HOL (previously called CHOL) uses a curried syntax
  2146 for functions.  Application looks like f a b instead of f(a,b);
  2147 
  2148 * Mutually recursive inductive definitions finally work in HOL;
  2149 
  2150 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2151 translates to the operator "split";
  2152 
  2153 
  2154 
  2155 New in Isabelle94-3
  2156 -------------------
  2157 
  2158 * new infix operator, addss, allowing the classical reasoner to
  2159 perform simplification at each step of its search.  Example:
  2160         fast_tac (cs addss ss)
  2161 
  2162 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2163 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2164 look like (a,b) instead of <a,b>;
  2165 
  2166 * PLEASE NOTE: CHOL will eventually replace HOL!
  2167 
  2168 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2169 It translates to the operator "split".  A new theory of integers is available;
  2170 
  2171 * In ZF, integer numerals now denote two's-complement binary integers.
  2172 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2173 
  2174 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2175 of the Axiom of Choice;
  2176 
  2177 
  2178 
  2179 New in Isabelle94-2
  2180 -------------------
  2181 
  2182 * Significantly faster resolution;
  2183 
  2184 * the different sections in a .thy file can now be mixed and repeated
  2185 freely;
  2186 
  2187 * Database of theorems for FOL, HOL and ZF.  New
  2188 commands including qed, qed_goal and bind_thm store theorems in the database.
  2189 
  2190 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2191 a given theory (thms_of), or find out what theory a theorem was proved in
  2192 (theory_of_thm);
  2193 
  2194 * Bugs fixed in the inductive definition and datatype packages;
  2195 
  2196 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2197 and HOL_dup_cs obsolete;
  2198 
  2199 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2200 have been removed;
  2201 
  2202 * Simpler definition of function space in ZF;
  2203 
  2204 * new results about cardinal and ordinal arithmetic in ZF;
  2205 
  2206 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2207 types;
  2208 
  2209 
  2210 $Id$