NEWS
author wenzelm
Sat Dec 01 18:50:41 2001 +0100 (2001-12-01)
changeset 12335 db4d5f498742
parent 12312 f0f06950820d
child 12364 108cdda23ab3
permissions -rw-r--r--
* HOL: the class of all HOL types is now called "type" rather than
"term"; INCOMPATIBILITY, need to adapt references to this type class
in axclass/classes, instance/arities, and (usually rare) occurrences
in typings (of consts etc.); internally the class is called
"HOL.type", ML programs should refer to HOLogic.typeS;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     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 Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol;
    31 
    32 
    33 *** Isar ***
    34 
    35 * Pure/Provers: improved proof by cases and induction;
    36   - 'case' command admits impromptu naming of parameters (such as
    37     "case (Suc n)");
    38   - 'induct' method divinates rule instantiation from the inductive
    39     claim; no longer requires excessive ?P bindings for proper
    40     instantiation of cases;
    41   - 'induct' method properly enumerates all possibilities of set/type
    42     rules; as a consequence facts may be also passed through *type*
    43     rules without further ado;
    44   - 'induct' method now derives symbolic cases from the *rulified*
    45     rule (before it used to rulify cases stemming from the internal
    46     atomized version); this means that the context of a non-atomic
    47     statement becomes is included in the hypothesis, avoiding the
    48     slightly cumbersome show "PROP ?case" form;
    49   - 'induct' may now use elim-style induction rules without chaining
    50     facts, using ``missing'' premises from the goal state; this allows
    51     rules stemming from inductive sets to be applied in unstructured
    52     scripts, while still benefitting from proper handling of non-atomic
    53     statements; NB: major inductive premises need to be put first, all
    54     the rest of the goal is passed through the induction;
    55   - 'induct' proper support for mutual induction involving non-atomic
    56     rule statements (uses the new concept of simultaneous goals, see
    57     below);
    58   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    59   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    60   - moved induct/cases attributes to Pure, methods to Provers;
    61   - generic method setup instantiated for FOL and HOL;
    62 
    63 * Pure: support multiple simultaneous goal statements, for example
    64 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    65 meta-level mechanism, this acts as if several individual goals had
    66 been stated separately; in particular common proof methods need to be
    67 repeated in order to cover all claims; note that a single elimination
    68 step is *not* sufficient to establish the two conjunctions, so this
    69 fails:
    70 
    71   assume "A & B" then have A and B ..   (*".." fails*)
    72 
    73 better use "obtain" in situations as above; alternative refer to
    74 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    75 
    76 * Pure: proper integration with ``locales''; unlike the original
    77 version by Florian Kammüller, Isar locales package high-level proof
    78 contexts rather than raw logical ones (e.g. we admit to include
    79 attributes everywhere); operations on locales include merge and
    80 rename; e.g. see HOL/ex/Locales.thy;
    81 
    82 * Pure: theory goals now support ad-hoc contexts, which are discharged
    83 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    84 coincides with that of a locale body;
    85 
    86 * Pure: renamed "antecedent" case to "rule_context";
    87 
    88 * Pure: added 'corollary' command;
    89 
    90 * Pure: fixed 'token_translation' command;
    91 
    92 * Pure: removed obsolete 'exported' attribute;
    93 
    94 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    95 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    96 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    97 
    98 * Pure: method 'atomize' presents local goal premises as object-level
    99 statements (atomic meta-level propositions); setup controlled via
   100 rewrite rules declarations of 'atomize' attribute; example
   101 application: 'induct' method with proper rule statements in improper
   102 proof *scripts*;
   103 
   104 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   105 now consider the syntactic context of assumptions, giving a better
   106 chance to get type-inference of the arguments right (this is
   107 especially important for locales);
   108 
   109 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   110 mode;
   111 
   112 * Provers: 'simplified' attribute may refer to explicit rules instead
   113 of full simplifier context; 'iff' attribute handles conditional rules;
   114 
   115 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   116 
   117 * HOL: 'recdef' now fails on unfinished automated proofs, use
   118 "(permissive)" option to recover old behavior;
   119 
   120 * HOL: 'inductive' no longer features separate (collective) attributes
   121 for 'intros' (was found too confusing);
   122 
   123 * HOLCF: domain package adapted to new-style theories, e.g. see
   124 HOLCF/ex/Dnat.thy;
   125 
   126 * ZF: proper integration of logic-specific tools and packages,
   127 including theory commands '(co)inductive', '(co)datatype',
   128 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   129 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   130 
   131 
   132 
   133 *** HOL ***
   134 
   135 * HOL: moved over to sane numeral syntax; the new policy is as
   136 follows:
   137 
   138   - 0 and 1 are polymorphic constants, which are defined on any
   139   numeric type (nat, int, real etc.);
   140 
   141   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   142   binary representation internally;
   143 
   144   - type nat has special constructor Suc, and generally prefers Suc 0
   145   over 1::nat and Suc (Suc 0) over 2::nat;
   146 
   147 This change may cause significant INCOMPATIBILITIES; here are some
   148 hints on converting existing sources:
   149 
   150   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   151   entities, so expressions involving "-" (unary or binary minus) need
   152   to be spaced properly;
   153 
   154   - existing occurrences of "1" may need to be constraint "1::nat" or
   155   even replaced by Suc 0; similar for old "2";
   156 
   157   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   158 
   159   - remove all special provisions on numerals in proofs;
   160 
   161 * HOL: the class of all HOL types is now called "type" rather than
   162 "term"; INCOMPATIBILITY, need to adapt references to this type class
   163 in axclass/classes, instance/arities, and (usually rare) occurrences
   164 in typings (of consts etc.); internally the class is called
   165 "HOL.type", ML programs should refer to HOLogic.typeS;
   166 
   167 * HOL/record package improvements:
   168   - new derived operations "fields" to build a partial record section,
   169     "extend" to promote a fixed record to a record scheme, and
   170     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   171     declared as simp by default;
   172   - removed "make_scheme" operations (use "make" with "extend") --
   173     INCOMPATIBILITY;
   174   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   175   - provides cases/induct rules for use with corresponding Isar
   176     methods (for concrete records, record schemes, concrete more
   177     parts, and schematic more parts -- in that order);
   178   - internal definitions directly based on a light-weight abstract
   179     theory of product types over typedef rather than datatype;
   180 
   181 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   182 
   183 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   184 (beware of argument permutation!);
   185 
   186 * HOL: linorder_less_split superseded by linorder_cases;
   187 
   188 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   189 to peripheral theory "Hilbert_Choice";
   190 
   191 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   192 in this (rare) case use:
   193 
   194   delSWrapper "split_all_tac"
   195   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   196 
   197 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   198 MAY FAIL;
   199 
   200 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   201 Isabelle's type classes, ^ on functions and relations has too general
   202 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   203 necessary to attach explicit type constraints;
   204 
   205 * HOL: syntax translations now work properly with numerals and records
   206 expressions;
   207 
   208 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   209 Florian Kammüller;
   210 
   211 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   212 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   213 renamed "Product_Type.unit";
   214 
   215 
   216 *** HOLCF ***
   217 
   218 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
   219 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   220 lift.induct_tac, always use UU instead of Undef;
   221 
   222 
   223 *** ZF ***
   224 
   225 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   226 typeless version of the formalism;
   227 
   228 * ZF/Induct: new directory for examples of inductive definitions,
   229 including theory Multiset for multiset orderings;
   230 
   231 * ZF: the integer library now covers quotients and remainders, with
   232 many laws relating division to addition, multiplication, etc.;
   233 
   234 
   235 *** General ***
   236 
   237 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   238 variable proof controls level of detail: 0 = no proofs (only oracle
   239 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   240 also ref manual for further ML interfaces;
   241 
   242 * Pure/axclass: removed obsolete ML interface
   243 goal_subclass/goal_arity;
   244 
   245 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   246 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   247 separate tokens, so expressions involving minus need to be spaced
   248 properly;
   249 
   250 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   251 rather than "infixl" or "infixr";
   252 
   253 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   254 sort constraint specifications in type inference; e.g. "x::_::foo"
   255 ensures that the type of "x" is of sort "foo" (but not necessarily a
   256 type variable);
   257 
   258 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   259 control output of nested => (types); the default behavior is
   260 "type_brackets";
   261 
   262 * Pure/syntax: builtin parse translation for "_constify" turns valued
   263 tokens into AST constants;
   264 
   265 * Pure/syntax: prefer later declarations of translations and print
   266 translation functions; potential INCOMPATIBILITY: need to reverse
   267 multiple declarations for same syntax element constant;
   268 
   269 * Provers/classical: renamed addaltern to addafter, addSaltern to
   270 addSafter;
   271 
   272 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   273 as well;
   274 
   275 * system: refrain from any attempt at filtering input streams; no
   276 longer support ``8bit'' encoding of old isabelle font, instead proper
   277 iso-latin characters may now be used;
   278 
   279 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   280 
   281 * system: Proof General keywords specification is now part of the
   282 Isabelle distribution (see etc/isar-keywords.el);
   283 
   284 * system: smart selection of Isabelle process versus Isabelle
   285 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   286 run both "isabelle" and "Isabelle" even if file names are badly
   287 damaged (executable inspects the case of the first letter of its own
   288 name); added separate "isabelle-process" and "isabelle-interface";
   289 
   290 
   291 
   292 New in Isabelle99-2 (February 2001)
   293 -----------------------------------
   294 
   295 *** Overview of INCOMPATIBILITIES ***
   296 
   297 * HOL: please note that theories in the Library and elsewhere often use the
   298 new-style (Isar) format; to refer to their theorems in an ML script you must
   299 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   300 
   301 * HOL: inductive package no longer splits induction rule aggressively,
   302 but only as far as specified by the introductions given; the old
   303 format may be recovered via ML function complete_split_rule or attribute
   304 'split_rule (complete)';
   305 
   306 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   307 gfp_Tarski to gfp_unfold;
   308 
   309 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   310 
   311 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   312 relation); infix "^^" has been renamed "``"; infix "``" has been
   313 renamed "`"; "univalent" has been renamed "single_valued";
   314 
   315 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   316 operation;
   317 
   318 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   319 
   320 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   321 
   322 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   323 consequence, it is no longer monotonic wrt. the local goal context
   324 (which is now passed through the inductive cases);
   325 
   326 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   327 \<gg> to \<ggreater>;
   328 
   329 
   330 *** Document preparation ***
   331 
   332 * \isabellestyle{NAME} selects version of Isabelle output (currently
   333 available: are "it" for near math-mode best-style output, "sl" for
   334 slanted text style, and "tt" for plain type-writer; if no
   335 \isabellestyle command is given, output is according to slanted
   336 type-writer);
   337 
   338 * support sub/super scripts (for single symbols only), input syntax is
   339 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   340 
   341 * some more standard symbols; see Appendix A of the system manual for
   342 the complete list of symbols defined in isabellesym.sty;
   343 
   344 * improved isabelle style files; more abstract symbol implementation
   345 (should now use \isamath{...} and \isatext{...} in custom symbol
   346 definitions);
   347 
   348 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   349 state; Note that presentation of goal states does not conform to
   350 actual human-readable proof documents.  Please do not include goal
   351 states into document output unless you really know what you are doing!
   352 
   353 * proper indentation of antiquoted output with proportional LaTeX
   354 fonts;
   355 
   356 * no_document ML operator temporarily disables LaTeX document
   357 generation;
   358 
   359 * isatool unsymbolize tunes sources for plain ASCII communication;
   360 
   361 
   362 *** Isar ***
   363 
   364 * Pure: Isar now suffers initial goal statements to contain unbound
   365 schematic variables (this does not conform to actual readable proof
   366 documents, due to unpredictable outcome and non-compositional proof
   367 checking); users who know what they are doing may use schematic goals
   368 for Prolog-style synthesis of proven results;
   369 
   370 * Pure: assumption method (an implicit finishing) now handles actual
   371 rules as well;
   372 
   373 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   374 initial goal, declare "that" only as Pure intro (only for single
   375 steps); the "that" rule assumption may now be involved in implicit
   376 finishing, thus ".." becomes a feasible for trivial obtains;
   377 
   378 * Pure: default proof step now includes 'intro_classes'; thus trivial
   379 instance proofs may be performed by "..";
   380 
   381 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   382 statements as well;
   383 
   384 * Pure: more robust selection of calculational rules;
   385 
   386 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   387 rule (as well as the assumption rule);
   388 
   389 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   390 lemmas, using the graph browser tool;
   391 
   392 * Pure: predict failure of "show" in interactive mode;
   393 
   394 * Pure: 'thms_containing' now takes actual terms as arguments;
   395 
   396 * HOL: improved method 'induct' --- now handles non-atomic goals
   397 (potential INCOMPATIBILITY); tuned error handling;
   398 
   399 * HOL: cases and induct rules now provide explicit hints about the
   400 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   401 any remaining facts are inserted into the goal verbatim;
   402 
   403 * HOL: local contexts (aka cases) may now contain term bindings as
   404 well; the 'cases' and 'induct' methods new provide a ?case binding for
   405 the result to be shown in each case;
   406 
   407 * HOL: added 'recdef_tc' command;
   408 
   409 * isatool convert assists in eliminating legacy ML scripts;
   410 
   411 
   412 *** HOL ***
   413 
   414 * HOL/Library: a collection of generic theories to be used together
   415 with main HOL; the theory loader path already includes this directory
   416 by default; the following existing theories have been moved here:
   417 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   418 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   419 
   420 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   421 modelling and verification task performed in Isabelle/HOL +
   422 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   423 
   424 * HOL/Algebra: special summation operator SUM no longer exists, it has
   425 been replaced by setsum; infix 'assoc' now has priority 50 (like
   426 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   427 'domain', this makes the theory consistent with mathematical
   428 literature;
   429 
   430 * HOL basics: added overloaded operations "inverse" and "divide"
   431 (infix "/"), syntax for generic "abs" operation, generic summation
   432 operator \<Sum>;
   433 
   434 * HOL/typedef: simplified package, provide more useful rules (see also
   435 HOL/subset.thy);
   436 
   437 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   438 now expressed as a proper nested rule (old-style tactic scripts may
   439 require atomize_strip_tac to cope with non-atomic premises);
   440 
   441 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   442 to "split_conv" (old name still available for compatibility);
   443 
   444 * HOL: improved concrete syntax for strings (e.g. allows translation
   445 rules with string literals);
   446 
   447 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   448  and Fleuriot's mechanization of analysis, including the transcendental
   449  functions for the reals;
   450 
   451 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   452 
   453 
   454 *** CTT ***
   455 
   456 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   457 "lam" is displayed as TWO lambda-symbols
   458 
   459 * CTT: theory Main now available, containing everything (that is, Bool
   460 and Arith);
   461 
   462 
   463 *** General ***
   464 
   465 * Pure: the Simplifier has been implemented properly as a derived rule
   466 outside of the actual kernel (at last!); the overall performance
   467 penalty in practical applications is about 50%, while reliability of
   468 the Isabelle inference kernel has been greatly improved;
   469 
   470 * print modes "brackets" and "no_brackets" control output of nested =>
   471 (types) and ==> (props); the default behaviour is "brackets";
   472 
   473 * Provers: fast_tac (and friends) now handle actual object-logic rules
   474 as assumptions as well;
   475 
   476 * system: support Poly/ML 4.0;
   477 
   478 * system: isatool install handles KDE version 1 or 2;
   479 
   480 
   481 
   482 New in Isabelle99-1 (October 2000)
   483 ----------------------------------
   484 
   485 *** Overview of INCOMPATIBILITIES ***
   486 
   487 * HOL: simplification of natural numbers is much changed; to partly
   488 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   489 issue the following ML commands:
   490 
   491   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   492   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   493 
   494 * HOL: simplification no longer dives into case-expressions; this is
   495 controlled by "t.weak_case_cong" for each datatype t;
   496 
   497 * HOL: nat_less_induct renamed to less_induct;
   498 
   499 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   500 fixsome to patch .thy and .ML sources automatically;
   501 
   502   select_equality  -> some_equality
   503   select_eq_Ex     -> some_eq_ex
   504   selectI2EX       -> someI2_ex
   505   selectI2         -> someI2
   506   selectI          -> someI
   507   select1_equality -> some1_equality
   508   Eps_sym_eq       -> some_sym_eq_trivial
   509   Eps_eq           -> some_eq_trivial
   510 
   511 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   512 
   513 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   514 instead);
   515 
   516 * HOL: the recursion equations generated by 'recdef' are now called
   517 f.simps instead of f.rules;
   518 
   519 * HOL: qed_spec_mp now also handles bounded ALL as well;
   520 
   521 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   522 sometimes be needed;
   523 
   524 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   525 
   526 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   527 
   528 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   529 product is now "<*>" instead of "Times"; the lexicographic product is
   530 now "<*lex*>" instead of "**";
   531 
   532 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   533 of main HOL, but was unused); better use HOL's datatype package;
   534 
   535 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   536 the old syntax may be recovered as follows:
   537 
   538   syntax (symbols)
   539     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   540       (infixl "\\<oplus>" 100)
   541 
   542 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   543 
   544 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   545 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   546 internally;
   547 
   548 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   549 changed from A/r to A//r;
   550 
   551 * ZF: new treatment of arithmetic (nat & int) may break some old
   552 proofs;
   553 
   554 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   555 rulify -> rule_format, elimify -> elim_format, ...);
   556 
   557 * Isar/Provers: intro/elim/dest attributes changed; renamed
   558 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   559 should have to change intro!! to intro? only); replaced "delrule" by
   560 "rule del";
   561 
   562 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   563 
   564 * Provers: strengthened force_tac by using new first_best_tac;
   565 
   566 * LaTeX document preparation: several changes of isabelle.sty (see
   567 lib/texinputs);
   568 
   569 
   570 *** Document preparation ***
   571 
   572 * formal comments (text blocks etc.) in new-style theories may now
   573 contain antiquotations of thm/prop/term/typ/text to be presented
   574 according to latex print mode; concrete syntax is like this:
   575 @{term[show_types] "f(x) = a + x"};
   576 
   577 * isatool mkdir provides easy setup of Isabelle session directories,
   578 including proper document sources;
   579 
   580 * generated LaTeX sources are now deleted after successful run
   581 (isatool document -c); may retain a copy somewhere else via -D option
   582 of isatool usedir;
   583 
   584 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   585 style files, achieving self-contained LaTeX sources and simplifying
   586 LaTeX debugging;
   587 
   588 * old-style theories now produce (crude) LaTeX output as well;
   589 
   590 * browser info session directories are now self-contained (may be put
   591 on WWW server seperately); improved graphs of nested sessions; removed
   592 graph for 'all sessions';
   593 
   594 * several improvements in isabelle style files; \isabellestyle{it}
   595 produces fake math mode output; \isamarkupheader is now \section by
   596 default; see lib/texinputs/isabelle.sty etc.;
   597 
   598 
   599 *** Isar ***
   600 
   601 * Isar/Pure: local results and corresponding term bindings are now
   602 subject to Hindley-Milner polymorphism (similar to ML); this
   603 accommodates incremental type-inference very nicely;
   604 
   605 * Isar/Pure: new derived language element 'obtain' supports
   606 generalized existence reasoning;
   607 
   608 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   609 support accumulation of results, without applying any rules yet;
   610 useful to collect intermediate results without explicit name
   611 references, and for use with transitivity rules with more than 2
   612 premises;
   613 
   614 * Isar/Pure: scalable support for case-analysis type proofs: new
   615 'case' language element refers to local contexts symbolically, as
   616 produced by certain proof methods; internally, case names are attached
   617 to theorems as "tags";
   618 
   619 * Isar/Pure: theory command 'hide' removes declarations from
   620 class/type/const name spaces;
   621 
   622 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   623 indicate potential overloading;
   624 
   625 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   626 
   627 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   628 "{a,b,c}" instead of {a,b,c};
   629 
   630 * Isar/Pure now provides its own version of intro/elim/dest
   631 attributes; useful for building new logics, but beware of confusion
   632 with the version in Provers/classical;
   633 
   634 * Isar/Pure: the local context of (non-atomic) goals is provided via
   635 case name 'antecedent';
   636 
   637 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   638 to the current context is now done automatically);
   639 
   640 * Isar/Pure: theory command 'method_setup' provides a simple interface
   641 for definining proof methods in ML;
   642 
   643 * Isar/Provers: intro/elim/dest attributes changed; renamed
   644 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   645 most cases, one should have to change intro!! to intro? only);
   646 replaced "delrule" by "rule del";
   647 
   648 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   649 'symmetric' attribute (the latter supercedes [RS sym]);
   650 
   651 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   652 method modifier); 'simp' method: 'only:' modifier removes loopers as
   653 well (including splits);
   654 
   655 * Isar/Provers: Simplifier and Classical methods now support all kind
   656 of modifiers used in the past, including 'cong', 'iff', etc.
   657 
   658 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   659 of Simplifier and Classical reasoner);
   660 
   661 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   662 now support named cases; major packages (inductive, datatype, primrec,
   663 recdef) support case names and properly name parameters;
   664 
   665 * Isar/HOL: new transitivity rules for substitution in inequalities --
   666 monotonicity conditions are extracted to be proven at end of
   667 calculations;
   668 
   669 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   670 method anyway;
   671 
   672 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   673 split_if split_if_asm; datatype package provides theorems foo.splits =
   674 foo.split foo.split_asm for each datatype;
   675 
   676 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   677 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   678 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   679 use "(cases (simplified))" method in proper proof texts);
   680 
   681 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   682 
   683 * Isar: names of theorems etc. may be natural numbers as well;
   684 
   685 * Isar: 'pr' command: optional arguments for goals_limit and
   686 ProofContext.prems_limit; no longer prints theory contexts, but only
   687 proof states;
   688 
   689 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   690 additional print modes to be specified; e.g. "pr(latex)" will print
   691 proof state according to the Isabelle LaTeX style;
   692 
   693 * Isar: improved support for emulating tactic scripts, including proof
   694 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   695 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   696 (for HOL datatypes);
   697 
   698 * Isar: simplified (more robust) goal selection of proof methods: 1st
   699 goal, all goals, or explicit goal specifier (tactic emulation); thus
   700 'proof method scripts' have to be in depth-first order;
   701 
   702 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   703 
   704 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   705 should instead use individual commands for printing items
   706 (print_commands, print_methods etc.);
   707 
   708 * Isar: added 'nothing' --- the empty list of theorems;
   709 
   710 
   711 *** HOL ***
   712 
   713 * HOL/MicroJava: formalization of a fragment of Java, together with a
   714 corresponding virtual machine and a specification of its bytecode
   715 verifier and a lightweight bytecode verifier, including proofs of
   716 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   717 Cornelia Pusch (see also the homepage of project Bali at
   718 http://isabelle.in.tum.de/Bali/);
   719 
   720 * HOL/Algebra: new theory of rings and univariate polynomials, by
   721 Clemens Ballarin;
   722 
   723 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   724 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   725 Rasmussen;
   726 
   727 * HOL/Lattice: fundamental concepts of lattice theory and order
   728 structures, including duals, properties of bounds versus algebraic
   729 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   730 Theorem for complete lattices etc.; may also serve as a demonstration
   731 for abstract algebraic reasoning using axiomatic type classes, and
   732 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   733 
   734 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   735 von Oheimb;
   736 
   737 * HOL/IMPP: extension of IMP with local variables and mutually
   738 recursive procedures, by David von Oheimb;
   739 
   740 * HOL/Lambda: converted into new-style theory and document;
   741 
   742 * HOL/ex/Multiquote: example of multiple nested quotations and
   743 anti-quotations -- basically a generalized version of de-Bruijn
   744 representation; very useful in avoiding lifting of operations;
   745 
   746 * HOL/record: added general record equality rule to simpset; fixed
   747 select-update simplification procedure to handle extended records as
   748 well; admit "r" as field name;
   749 
   750 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   751 other numeric types and also as the identity of groups, rings, etc.;
   752 
   753 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   754 Types nat and int belong to this axclass;
   755 
   756 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   757    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   758    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   759   two terms #m*u and #n*u are replaced by #(m+n)*u
   760     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   761   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   762     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   763 
   764 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   765 powerful prover for predicate logic but knows nothing of clasets; see
   766 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   767 
   768 * HOL: new version of "case_tac" subsumes both boolean case split and
   769 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   770 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   771 
   772 * HOL: simplification no longer dives into case-expressions: only the
   773 selector expression is simplified, but not the remaining arms; to
   774 enable full simplification of case-expressions for datatype t, you may
   775 remove t.weak_case_cong from the simpset, either globally (Delcongs
   776 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   777 
   778 * HOL/recdef: the recursion equations generated by 'recdef' for
   779 function 'f' are now called f.simps instead of f.rules; if all
   780 termination conditions are proved automatically, these simplification
   781 rules are added to the simpset, as in primrec; rules may be named
   782 individually as well, resulting in a separate list of theorems for
   783 each equation;
   784 
   785 * HOL/While is a new theory that provides a while-combinator. It
   786 permits the definition of tail-recursive functions without the
   787 provision of a termination measure. The latter is necessary once the
   788 invariant proof rule for while is applied.
   789 
   790 * HOL: new (overloaded) notation for the set of elements below/above
   791 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   792 
   793 * HOL: theorems impI, allI, ballI bound as "strip";
   794 
   795 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   796 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   797 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   798 
   799 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   800 
   801 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   802 main HOL, but was unused);
   803 
   804 * HOL: fewer consts declared as global (e.g. have to refer to
   805 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   806 
   807 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   808 in case of overlap with user translations (e.g. judgements over
   809 tuples); (note that the underlying logical represenation is still
   810 bogus);
   811 
   812 
   813 *** ZF ***
   814 
   815 * ZF: simplification automatically cancels common terms in arithmetic
   816 expressions over nat and int;
   817 
   818 * ZF: new treatment of nat to minimize type-checking: all operators
   819 coerce their operands to a natural number using the function natify,
   820 making the algebraic laws unconditional;
   821 
   822 * ZF: as above, for int: operators coerce their operands to an integer
   823 using the function intify;
   824 
   825 * ZF: the integer library now contains many of the usual laws for the
   826 orderings, including $<=, and monotonicity laws for $+ and $*;
   827 
   828 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   829 simplification;
   830 
   831 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   832 to the simplifier and classical reasoner simultaneously;
   833 
   834 
   835 *** General ***
   836 
   837 * Provers: blast_tac now handles actual object-logic rules as
   838 assumptions; note that auto_tac uses blast_tac internally as well;
   839 
   840 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   841 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   842 
   843 * Provers: delrules now handles destruct rules as well (no longer need
   844 explicit make_elim);
   845 
   846 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   847   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   848 use instead the strong form,
   849   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   850 in HOL, FOL and ZF the function cla_make_elim will create such rules
   851 from destruct-rules;
   852 
   853 * Provers: Simplifier.easy_setup provides a fast path to basic
   854 Simplifier setup for new object-logics;
   855 
   856 * Pure: AST translation rules no longer require constant head on LHS;
   857 
   858 * Pure: improved name spaces: ambiguous output is qualified; support
   859 for hiding of names;
   860 
   861 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   862 XSYMBOL_HOME; no longer need to do manual configuration in most
   863 situations;
   864 
   865 * system: compression of ML heaps images may now be controlled via -c
   866 option of isabelle and isatool usedir (currently only observed by
   867 Poly/ML);
   868 
   869 * system: isatool installfonts may handle X-Symbol fonts as well (very
   870 useful for remote X11);
   871 
   872 * system: provide TAGS file for Isabelle sources;
   873 
   874 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   875 order;
   876 
   877 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   878 timing flag supersedes proof_timing and Toplevel.trace;
   879 
   880 * ML: new combinators |>> and |>>> for incremental transformations
   881 with secondary results (e.g. certain theory extensions):
   882 
   883 * ML: PureThy.add_defs gets additional argument to indicate potential
   884 overloading (usually false);
   885 
   886 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   887 results;
   888 
   889 
   890 
   891 New in Isabelle99 (October 1999)
   892 --------------------------------
   893 
   894 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   895 
   896 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   897 are no longer simplified.  (This allows the simplifier to unfold recursive
   898 functional programs.)  To restore the old behaviour, declare
   899 
   900     Delcongs [if_weak_cong];
   901 
   902 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   903 complement;
   904 
   905 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   906 
   907 * HOL/datatype: mutual_induct_tac no longer exists --
   908   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   909 
   910 * HOL/typedef: fixed type inference for representing set; type
   911 arguments now have to occur explicitly on the rhs as type constraints;
   912 
   913 * ZF: The con_defs part of an inductive definition may no longer refer
   914 to constants declared in the same theory;
   915 
   916 * HOL, ZF: the function mk_cases, generated by the inductive
   917 definition package, has lost an argument.  To simplify its result, it
   918 uses the default simpset instead of a supplied list of theorems.
   919 
   920 * HOL/List: the constructors of type list are now Nil and Cons;
   921 
   922 * Simplifier: the type of the infix ML functions
   923         setSSolver addSSolver setSolver addSolver
   924 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   925 for packaging solvers. A solver is created via
   926         mk_solver: string -> (thm list -> int -> tactic) -> solver
   927 where the string argument is only a comment.
   928 
   929 
   930 *** Proof tools ***
   931 
   932 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   933 decision procedure for linear arithmetic. Currently it is used for
   934 types `nat', `int', and `real' in HOL (see below); it can, should and
   935 will be instantiated for other types and logics as well.
   936 
   937 * The simplifier now accepts rewrite rules with flexible heads, eg
   938      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   939   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   940   matching.
   941 
   942 
   943 *** General ***
   944 
   945 * New Isabelle/Isar subsystem provides an alternative to traditional
   946 tactical theorem proving; together with the ProofGeneral/isar user
   947 interface it offers an interactive environment for developing human
   948 readable proof documents (Isar == Intelligible semi-automated
   949 reasoning); for further information see isatool doc isar-ref,
   950 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   951 
   952 * improved and simplified presentation of theories: better HTML markup
   953 (including colors), graph views in several sizes; isatool usedir now
   954 provides a proper interface for user theories (via -P option); actual
   955 document preparation based on (PDF)LaTeX is available as well (for
   956 new-style theories only); see isatool doc system for more information;
   957 
   958 * native support for Proof General, both for classic Isabelle and
   959 Isabelle/Isar;
   960 
   961 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   962 using the graph browser tool;
   963 
   964 * Isabelle manuals now also available as PDF;
   965 
   966 * theory loader rewritten from scratch (may not be fully
   967 bug-compatible); old loadpath variable has been replaced by show_path,
   968 add_path, del_path, reset_path functions; new operations such as
   969 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   970 isatool doc ref);
   971 
   972 * improved isatool install: option -k creates KDE application icon,
   973 option -p DIR installs standalone binaries;
   974 
   975 * added ML_PLATFORM setting (useful for cross-platform installations);
   976 more robust handling of platform specific ML images for SML/NJ;
   977 
   978 * the settings environment is now statically scoped, i.e. it is never
   979 created again in sub-processes invoked from isabelle, isatool, or
   980 Isabelle;
   981 
   982 * path element specification '~~' refers to '$ISABELLE_HOME';
   983 
   984 * in locales, the "assumes" and "defines" parts may be omitted if
   985 empty;
   986 
   987 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   988 long arrows);
   989 
   990 * new print_mode "HTML";
   991 
   992 * new flag show_tags controls display of tags of theorems (which are
   993 basically just comments that may be attached by some tools);
   994 
   995 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   996 mode and goal output format:
   997 
   998 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   999 244c244
  1000 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1001 ---
  1002 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1003 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1004 181c181
  1005 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1006 ---
  1007 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1008 
  1009 * function bind_thms stores lists of theorems (cf. bind_thm);
  1010 
  1011 * new shorthand tactics ftac, eatac, datac, fatac;
  1012 
  1013 * qed (and friends) now accept "" as result name; in that case the
  1014 theorem is not stored, but proper checks and presentation of the
  1015 result still apply;
  1016 
  1017 * theorem database now also indexes constants "Trueprop", "all",
  1018 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1019 
  1020 
  1021 *** HOL ***
  1022 
  1023 ** HOL arithmetic **
  1024 
  1025 * There are now decision procedures for linear arithmetic over nat and
  1026 int:
  1027 
  1028 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1029 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1030 are treated as atomic; subformulae not involving type `nat' or `int'
  1031 are ignored; quantified subformulae are ignored unless they are
  1032 positive universal or negative existential. The tactic has to be
  1033 invoked by hand and can be a little bit slow. In particular, the
  1034 running time is exponential in the number of occurrences of `min' and
  1035 `max', and `-' on `nat'.
  1036 
  1037 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1038 (negated) (in)equalities among the premises and the conclusion into
  1039 account (i.e. no compound formulae) and does not know about `min' and
  1040 `max', and `-' on `nat'. It is fast and is used automatically by the
  1041 simplifier.
  1042 
  1043 NB: At the moment, these decision procedures do not cope with mixed
  1044 nat/int formulae where the two parts interact, such as `m < n ==>
  1045 int(m) < int(n)'.
  1046 
  1047 * HOL/Numeral provides a generic theory of numerals (encoded
  1048 efficiently as bit strings); setup for types nat/int/real is in place;
  1049 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1050 int, existing theories and proof scripts may require a few additional
  1051 type constraints;
  1052 
  1053 * integer division and remainder can now be performed on constant
  1054 arguments;
  1055 
  1056 * many properties of integer multiplication, division and remainder
  1057 are now available;
  1058 
  1059 * An interface to the Stanford Validity Checker (SVC) is available through the
  1060 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1061 are proved automatically.  SVC must be installed separately, and its results
  1062 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1063 invocation of the underlying oracle).  For SVC see
  1064   http://verify.stanford.edu/SVC
  1065 
  1066 * IsaMakefile: the HOL-Real target now builds an actual image;
  1067 
  1068 
  1069 ** HOL misc **
  1070 
  1071 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1072 (in Isabelle/Isar) -- by Gertrud Bauer;
  1073 
  1074 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1075 analysis for assembly languages with subtypes;
  1076 
  1077 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1078 -- avoids syntactic ambiguities and treats state, transition, and
  1079 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1080 changed syntax and (many) tactics;
  1081 
  1082 * HOL/inductive: Now also handles more general introduction rules such
  1083   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1084   theorems are now maintained within the theory (maintained via the
  1085   "mono" attribute);
  1086 
  1087 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1088   (using function types) such as
  1089 
  1090   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1091 
  1092 * HOL/record: record_simproc (part of the default simpset) takes care
  1093 of selectors applied to updated records; record_split_tac is no longer
  1094 part of the default claset; update_defs may now be removed from the
  1095 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1096 
  1097   claset_ref () := claset() addSWrapper record_split_wrapper;
  1098   Delsimprocs [record_simproc]
  1099 
  1100 * HOL/typedef: fixed type inference for representing set; type
  1101 arguments now have to occur explicitly on the rhs as type constraints;
  1102 
  1103 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1104 names rather than an ML expression;
  1105 
  1106 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1107 supplied later.  Program schemes can be defined, such as
  1108     "While B C s = (if B s then While B C (C s) else s)"
  1109 where the well-founded relation can be chosen after B and C have been given.
  1110 
  1111 * HOL/List: the constructors of type list are now Nil and Cons;
  1112 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1113 course, ML tools referring to List.list.op # etc. have to be adapted;
  1114 
  1115 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1116 disabled by default; run isabelle with option -m HOL to get back to
  1117 the original Gordon/HOL-style output;
  1118 
  1119 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1120 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1121 
  1122 * HOL basic syntax simplified (more orthogonal): all variants of
  1123 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1124 Eps operator is provided as well: "SOME x. P[x]";
  1125 
  1126 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1127 
  1128 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1129 thus available for user theories;
  1130 
  1131 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1132 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1133 time;
  1134 
  1135 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1136 several times and then mp;
  1137 
  1138 
  1139 *** LK ***
  1140 
  1141 * the notation <<...>> is now available as a notation for sequences of
  1142 formulas;
  1143 
  1144 * the simplifier is now installed
  1145 
  1146 * the axiom system has been generalized (thanks to Soren Heilmann)
  1147 
  1148 * the classical reasoner now has a default rule database
  1149 
  1150 
  1151 *** ZF ***
  1152 
  1153 * new primrec section allows primitive recursive functions to be given
  1154 directly (as in HOL) over datatypes and the natural numbers;
  1155 
  1156 * new tactics induct_tac and exhaust_tac for induction (or case
  1157 analysis) over datatypes and the natural numbers;
  1158 
  1159 * the datatype declaration of type T now defines the recursor T_rec;
  1160 
  1161 * simplification automatically does freeness reasoning for datatype
  1162 constructors;
  1163 
  1164 * automatic type-inference, with AddTCs command to insert new
  1165 type-checking rules;
  1166 
  1167 * datatype introduction rules are now added as Safe Introduction rules
  1168 to the claset;
  1169 
  1170 * the syntax "if P then x else y" is now available in addition to
  1171 if(P,x,y);
  1172 
  1173 
  1174 *** Internal programming interfaces ***
  1175 
  1176 * tuned simplifier trace output; new flag debug_simp;
  1177 
  1178 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1179 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1180 
  1181 * AxClass.axclass_tac lost the theory argument;
  1182 
  1183 * tuned current_goals_markers semantics: begin / end goal avoids
  1184 printing empty lines;
  1185 
  1186 * removed prs and prs_fn hook, which was broken because it did not
  1187 include \n in its semantics, forcing writeln to add one
  1188 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1189 string -> unit if you really want to output text without newline;
  1190 
  1191 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1192 plain output, interface builders may have to enable 'isabelle_font'
  1193 mode to get Isabelle font glyphs as before;
  1194 
  1195 * refined token_translation interface; INCOMPATIBILITY: output length
  1196 now of type real instead of int;
  1197 
  1198 * theory loader actions may be traced via new ThyInfo.add_hook
  1199 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1200 your own database of information attached to *whole* theories -- as
  1201 opposed to intra-theory data slots offered via TheoryDataFun;
  1202 
  1203 * proper handling of dangling sort hypotheses (at last!);
  1204 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1205 extra sort hypotheses that can be witnessed from the type signature;
  1206 the force_strip_shyps flag is gone, any remaining shyps are simply
  1207 left in the theorem (with a warning issued by strip_shyps_warning);
  1208 
  1209 
  1210 
  1211 New in Isabelle98-1 (October 1998)
  1212 ----------------------------------
  1213 
  1214 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1215 
  1216 * several changes of automated proof tools;
  1217 
  1218 * HOL: major changes to the inductive and datatype packages, including
  1219 some minor incompatibilities of theory syntax;
  1220 
  1221 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1222 called `inj_on';
  1223 
  1224 * HOL: removed duplicate thms in Arith:
  1225   less_imp_add_less  should be replaced by  trans_less_add1
  1226   le_imp_add_le      should be replaced by  trans_le_add1
  1227 
  1228 * HOL: unary minus is now overloaded (new type constraints may be
  1229 required);
  1230 
  1231 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1232 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1233 now taken as an integer constant.
  1234 
  1235 * Pure: ML function 'theory_of' renamed to 'theory';
  1236 
  1237 
  1238 *** Proof tools ***
  1239 
  1240 * Simplifier:
  1241   1. Asm_full_simp_tac is now more aggressive.
  1242      1. It will sometimes reorient premises if that increases their power to
  1243         simplify.
  1244      2. It does no longer proceed strictly from left to right but may also
  1245         rotate premises to achieve further simplification.
  1246      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1247      old Asm_full_simp_tac in that it does not rotate premises.
  1248   2. The simplifier now knows a little bit about nat-arithmetic.
  1249 
  1250 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1251 allows for selected deletion of wrappers, by introduction of names for
  1252 wrapper functionals.  This implies that addbefore, addSbefore,
  1253 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1254 and that adding two tactics with the same name overwrites the first
  1255 one (emitting a warning).
  1256   type wrapper = (int -> tactic) -> (int -> tactic)
  1257   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1258   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1259   delWrapper, delSWrapper: claset *  string            -> claset
  1260   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1261 
  1262 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1263 semantics; addbefore now affects only the unsafe part of step_tac
  1264 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1265 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1266 by Force_tac;
  1267 
  1268 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1269 compWrapper; added safe wrapper (and access functions for it);
  1270 
  1271 * HOL/split_all_tac is now much faster and fails if there is nothing
  1272 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1273 and the names of the automatically generated variables have changed.
  1274 split_all_tac has moved within claset() from unsafe wrappers to safe
  1275 wrappers, which means that !!-bound variables are split much more
  1276 aggressively, and safe_tac and clarify_tac now split such variables.
  1277 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1278 Note: the same holds for record_split_tac, which does the job of
  1279 split_all_tac for record fields.
  1280 
  1281 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1282 permanently to the default simpset using Addsplits just like
  1283 Addsimps. They can be removed via Delsplits just like
  1284 Delsimps. Lower-case versions are also available.
  1285 
  1286 * HOL/Simplifier: The rule split_if is now part of the default
  1287 simpset. This means that the simplifier will eliminate all occurrences
  1288 of if-then-else in the conclusion of a goal. To prevent this, you can
  1289 either remove split_if completely from the default simpset by
  1290 `Delsplits [split_if]' or remove it in a specific call of the
  1291 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1292 other case splitting rules to/from the default simpset: every datatype
  1293 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1294 t is the name of the datatype).
  1295 
  1296 * Classical reasoner / Simplifier combination: new force_tac (and
  1297 derivatives Force_tac, force) combines rewriting and classical
  1298 reasoning (and whatever other tools) similarly to auto_tac, but is
  1299 aimed to solve the given subgoal completely.
  1300 
  1301 
  1302 *** General ***
  1303 
  1304 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1305 and `goalw': the theory is no longer needed as an explicit argument -
  1306 the current theory context is used; assumptions are no longer returned
  1307 at the ML-level unless one of them starts with ==> or !!; it is
  1308 recommended to convert to these new commands using isatool fixgoal
  1309 (backup your sources first!);
  1310 
  1311 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1312 the current theory context, and 'theory' to lookup stored theories;
  1313 
  1314 * new theory section 'locale' for declaring constants, assumptions and
  1315 definitions that have local scope;
  1316 
  1317 * new theory section 'nonterminals' for purely syntactic types;
  1318 
  1319 * new theory section 'setup' for generic ML setup functions
  1320 (e.g. package initialization);
  1321 
  1322 * the distribution now includes Isabelle icons: see
  1323 lib/logo/isabelle-{small,tiny}.xpm;
  1324 
  1325 * isatool install - install binaries with absolute references to
  1326 ISABELLE_HOME/bin;
  1327 
  1328 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1329 
  1330 * print mode 'emacs' reserved for Isamode;
  1331 
  1332 * support multiple print (ast) translations per constant name;
  1333 
  1334 * theorems involving oracles are now printed with a suffixed [!];
  1335 
  1336 
  1337 *** HOL ***
  1338 
  1339 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1340 
  1341 * HOL/inductive package reorganized and improved: now supports mutual
  1342 definitions such as
  1343 
  1344   inductive EVEN ODD
  1345     intrs
  1346       null "0 : EVEN"
  1347       oddI "n : EVEN ==> Suc n : ODD"
  1348       evenI "n : ODD ==> Suc n : EVEN"
  1349 
  1350 new theorem list "elims" contains an elimination rule for each of the
  1351 recursive sets; inductive definitions now handle disjunctive premises
  1352 correctly (also ZF);
  1353 
  1354 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1355 "mutual_induct" no longer exists - the induction rule is always
  1356 contained in "induct";
  1357 
  1358 
  1359 * HOL/datatype package re-implemented and greatly improved: now
  1360 supports mutually recursive datatypes such as
  1361 
  1362   datatype
  1363     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1364             | SUM ('a aexp) ('a aexp)
  1365             | DIFF ('a aexp) ('a aexp)
  1366             | NUM 'a
  1367   and
  1368     'a bexp = LESS ('a aexp) ('a aexp)
  1369             | AND ('a bexp) ('a bexp)
  1370             | OR ('a bexp) ('a bexp)
  1371 
  1372 as well as indirectly recursive datatypes such as
  1373 
  1374   datatype
  1375     ('a, 'b) term = Var 'a
  1376                   | App 'b ((('a, 'b) term) list)
  1377 
  1378 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1379 induction on mutually / indirectly recursive datatypes.
  1380 
  1381 Primrec equations are now stored in theory and can be accessed via
  1382 <function_name>.simps.
  1383 
  1384 INCOMPATIBILITIES:
  1385 
  1386   - Theories using datatypes must now have theory Datatype as an
  1387     ancestor.
  1388   - The specific <typename>.induct_tac no longer exists - use the
  1389     generic induct_tac instead.
  1390   - natE has been renamed to nat.exhaust - use exhaust_tac
  1391     instead of res_inst_tac ... natE. Note that the variable
  1392     names in nat.exhaust differ from the names in natE, this
  1393     may cause some "fragile" proofs to fail.
  1394   - The theorems split_<typename>_case and split_<typename>_case_asm
  1395     have been renamed to <typename>.split and <typename>.split_asm.
  1396   - Since default sorts of type variables are now handled correctly,
  1397     some datatype definitions may have to be annotated with explicit
  1398     sort constraints.
  1399   - Primrec definitions no longer require function name and type
  1400     of recursive argument.
  1401 
  1402 Consider using isatool fixdatatype to adapt your theories and proof
  1403 scripts to the new package (backup your sources first!).
  1404 
  1405 
  1406 * HOL/record package: considerably improved implementation; now
  1407 includes concrete syntax for record types, terms, updates; theorems
  1408 for surjective pairing and splitting !!-bound record variables; proof
  1409 support is as follows:
  1410 
  1411   1) standard conversions (selectors or updates applied to record
  1412 constructor terms) are part of the standard simpset;
  1413 
  1414   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1415 made part of standard simpset and claset via addIffs;
  1416 
  1417   3) a tactic for record field splitting (record_split_tac) is part of
  1418 the standard claset (addSWrapper);
  1419 
  1420 To get a better idea about these rules you may retrieve them via
  1421 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1422 the name of your record type.
  1423 
  1424 The split tactic 3) conceptually simplifies by the following rule:
  1425 
  1426   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1427 
  1428 Thus any record variable that is bound by meta-all will automatically
  1429 blow up into some record constructor term, consequently the
  1430 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1431 solve record problems automatically.
  1432 
  1433 
  1434 * reorganized the main HOL image: HOL/Integ and String loaded by
  1435 default; theory Main includes everything;
  1436 
  1437 * automatic simplification of integer sums and comparisons, using cancellation;
  1438 
  1439 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1440 
  1441 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1442 
  1443 * many new identities for unions, intersections, set difference, etc.;
  1444 
  1445 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1446 called split_if, split_split, split_sum_case and split_nat_case (to go
  1447 with add/delsplits);
  1448 
  1449 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1450 (?x::unit) = (); this is made part of the default simpset, which COULD
  1451 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1452 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1453 unit_abs_eta_conv is added in order to counter the effect of
  1454 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1455 %u.f();
  1456 
  1457 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1458 makes more sense);
  1459 
  1460 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1461   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1462   disjointness reasoning but breaking a few old proofs.
  1463 
  1464 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1465 to 'converse' from 'inverse' (for compatibility with ZF and some
  1466 literature);
  1467 
  1468 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1469 the well-founded relation;
  1470 
  1471 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1472     Compl A.  The "Compl" syntax remains available as input syntax for this
  1473     release ONLY.
  1474 
  1475 * HOL/Update: new theory of function updates:
  1476     f(a:=b) == %x. if x=a then b else f x
  1477 may also be iterated as in f(a:=b,c:=d,...);
  1478 
  1479 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1480 
  1481 * HOL/List:
  1482   - new function list_update written xs[i:=v] that updates the i-th
  1483     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1484   - new function `upt' written [i..j(] which generates the list
  1485     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1486     bound write [i..j], which is a shorthand for [i..j+1(].
  1487   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1488 
  1489 * HOL/Arith:
  1490   - removed 'pred' (predecessor) function;
  1491   - generalized some theorems about n-1;
  1492   - many new laws about "div" and "mod";
  1493   - new laws about greatest common divisors (see theory ex/Primes);
  1494 
  1495 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1496 instead of "inverse";
  1497 
  1498 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1499   of the multiset ordering;
  1500 
  1501 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1502   (not included by default);
  1503 
  1504 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1505 
  1506 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1507   programs, i.e. different program variables may have different types.
  1508 
  1509 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1510   [previously, this check worked only if the rewrite rule was unconditional]
  1511   Now rew can involve either definitions or equalities (either == or =).
  1512 
  1513 
  1514 *** ZF ***
  1515 
  1516 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1517   only the theorems proved on ZF.ML;
  1518 
  1519 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1520   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1521   disjointness reasoning but breaking a few old proofs.
  1522 
  1523 * ZF/Update: new theory of function updates
  1524     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1525   may also be iterated as in f(a:=b,c:=d,...);
  1526 
  1527 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1528 
  1529 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1530   [previously, this check worked only if the rewrite rule was unconditional]
  1531   Now rew can involve either definitions or equalities (either == or =).
  1532 
  1533 * case_tac provided for compatibility with HOL
  1534     (like the old excluded_middle_tac, but with subgoals swapped)
  1535 
  1536 
  1537 *** Internal programming interfaces ***
  1538 
  1539 * Pure: several new basic modules made available for general use, see
  1540 also src/Pure/README;
  1541 
  1542 * improved the theory data mechanism to support encapsulation (data
  1543 kind name replaced by private Object.kind, acting as authorization
  1544 key); new type-safe user interface via functor TheoryDataFun; generic
  1545 print_data function becomes basically useless;
  1546 
  1547 * removed global_names compatibility flag -- all theory declarations
  1548 are qualified by default;
  1549 
  1550 * module Pure/Syntax now offers quote / antiquote translation
  1551 functions (useful for Hoare logic etc. with implicit dependencies);
  1552 see HOL/ex/Antiquote for an example use;
  1553 
  1554 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1555 cterm -> thm;
  1556 
  1557 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1558 subgoal;
  1559 
  1560 * Display.print_goals function moved to Locale.print_goals;
  1561 
  1562 * standard print function for goals supports current_goals_markers
  1563 variable for marking begin of proof, end of proof, start of goal; the
  1564 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1565 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1566 for example;
  1567 
  1568 
  1569 
  1570 New in Isabelle98 (January 1998)
  1571 --------------------------------
  1572 
  1573 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1574 
  1575 * changed lexical syntax of terms / types: dots made part of long
  1576 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1577 
  1578 * simpset (and claset) reference variable replaced by functions
  1579 simpset / simpset_ref;
  1580 
  1581 * no longer supports theory aliases (via merge) and non-trivial
  1582 implicit merge of thms' signatures;
  1583 
  1584 * most internal names of constants changed due to qualified names;
  1585 
  1586 * changed Pure/Sequence interface (see Pure/seq.ML);
  1587 
  1588 
  1589 *** General Changes ***
  1590 
  1591 * hierachically structured name spaces (for consts, types, axms, thms
  1592 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1593 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1594 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1595 long_names for fully qualified output names; NOTE: ML programs
  1596 (special tactics, packages etc.) referring to internal names may have
  1597 to be adapted to cope with fully qualified names; in case of severe
  1598 backward campatibility problems try setting 'global_names' at compile
  1599 time to have enrything declared within a flat name space; one may also
  1600 fine tune name declarations in theories via the 'global' and 'local'
  1601 section;
  1602 
  1603 * reimplemented the implicit simpset and claset using the new anytype
  1604 data filed in signatures; references simpset:simpset ref etc. are
  1605 replaced by functions simpset:unit->simpset and
  1606 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1607 to patch your ML files accordingly;
  1608 
  1609 * HTML output now includes theory graph data for display with Java
  1610 applet or isatool browser; data generated automatically via isatool
  1611 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1612 
  1613 * defs may now be conditional; improved rewrite_goals_tac to handle
  1614 conditional equations;
  1615 
  1616 * defs now admits additional type arguments, using TYPE('a) syntax;
  1617 
  1618 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1619 creates a new theory node; implicit merge of thms' signatures is
  1620 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1621 transfer:theory->thm->thm in (rare) cases;
  1622 
  1623 * improved handling of draft signatures / theories; draft thms (and
  1624 ctyps, cterms) are automatically promoted to real ones;
  1625 
  1626 * slightly changed interfaces for oracles: admit many per theory, named
  1627 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1628 
  1629 * print_goals: optional output of const types (set show_consts and
  1630 show_types);
  1631 
  1632 * improved output of warnings (###) and errors (***);
  1633 
  1634 * subgoal_tac displays a warning if the new subgoal has type variables;
  1635 
  1636 * removed old README and Makefiles;
  1637 
  1638 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1639 
  1640 * removed obsolete init_pps and init_database;
  1641 
  1642 * deleted the obsolete tactical STATE, which was declared by
  1643     fun STATE tacfun st = tacfun st st;
  1644 
  1645 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1646 (which abbreviates $HOME);
  1647 
  1648 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1649 use isatool fixseq to adapt your ML programs (this works for fully
  1650 qualified references to the Sequence structure only!);
  1651 
  1652 * use_thy no longer requires writable current directory; it always
  1653 reloads .ML *and* .thy file, if either one is out of date;
  1654 
  1655 
  1656 *** Classical Reasoner ***
  1657 
  1658 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1659 tactics that use classical reasoning to simplify a subgoal without
  1660 splitting it into several subgoals;
  1661 
  1662 * Safe_tac: like safe_tac but uses the default claset;
  1663 
  1664 
  1665 *** Simplifier ***
  1666 
  1667 * added simplification meta rules:
  1668     (asm_)(full_)simplify: simpset -> thm -> thm;
  1669 
  1670 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1671 logics (again);
  1672 
  1673 * added prems argument to simplification procedures;
  1674 
  1675 * HOL, FOL, ZF: added infix function `addsplits':
  1676   instead of `<simpset> setloop (split_tac <thms>)'
  1677   you can simply write `<simpset> addsplits <thms>'
  1678 
  1679 
  1680 *** Syntax ***
  1681 
  1682 * TYPE('a) syntax for type reflection terms;
  1683 
  1684 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1685 
  1686 * pretty printer: changed order of mixfix annotation preference (again!);
  1687 
  1688 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1689 
  1690 
  1691 *** HOL ***
  1692 
  1693 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1694   with `addloop' of the simplifier to faciliate case splitting in premises.
  1695 
  1696 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1697 
  1698 * HOL/Auth: new protocol proofs including some for the Internet
  1699   protocol TLS;
  1700 
  1701 * HOL/Map: new theory of `maps' a la VDM;
  1702 
  1703 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1704 cancelling out common nat summands from =, <, <= (in)equalities, or
  1705 differences; simplification procedures nat_cancel_factor for
  1706 cancelling common factor from =, <, <= (in)equalities over natural
  1707 sums; nat_cancel contains both kinds of procedures, it is installed by
  1708 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1709 
  1710 * HOL/simplifier: terms of the form
  1711   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1712   are rewritten to
  1713   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1714   and those of the form
  1715   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1716   are rewritten to
  1717   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1718 
  1719 * HOL/datatype
  1720   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1721 
  1722   P(t_case f1 ... fn x) =
  1723      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1724         ...
  1725        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1726      )
  1727 
  1728   and a theorem `split_t_case_asm' of the form
  1729 
  1730   P(t_case f1 ... fn x) =
  1731     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1732         ...
  1733        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1734      )
  1735   which can be added to a simpset via `addsplits'. The existing theorems
  1736   expand_list_case and expand_option_case have been renamed to
  1737   split_list_case and split_option_case.
  1738 
  1739 * HOL/Arithmetic:
  1740   - `pred n' is automatically converted to `n-1'.
  1741     Users are strongly encouraged not to use `pred' any longer,
  1742     because it will disappear altogether at some point.
  1743   - Users are strongly encouraged to write "0 < n" rather than
  1744     "n ~= 0". Theorems and proof tools have been modified towards this
  1745     `standard'.
  1746 
  1747 * HOL/Lists:
  1748   the function "set_of_list" has been renamed "set" (and its theorems too);
  1749   the function "nth" now takes its arguments in the reverse order and
  1750   has acquired the infix notation "!" as in "xs!n".
  1751 
  1752 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1753 
  1754 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1755   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1756 
  1757 * HOL/record: extensible records with schematic structural subtyping
  1758 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1759 still lacks various theorems and concrete record syntax;
  1760 
  1761 
  1762 *** HOLCF ***
  1763 
  1764 * removed "axioms" and "generated by" sections;
  1765 
  1766 * replaced "ops" section by extended "consts" section, which is capable of
  1767   handling the continuous function space "->" directly;
  1768 
  1769 * domain package:
  1770   . proves theorems immediately and stores them in the theory,
  1771   . creates hierachical name space,
  1772   . now uses normal mixfix annotations (instead of cinfix...),
  1773   . minor changes to some names and values (for consistency),
  1774   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1775   . separator between mutual domain defs: changed "," to "and",
  1776   . improved handling of sort constraints;  now they have to
  1777     appear on the left-hand side of the equations only;
  1778 
  1779 * fixed LAM <x,y,zs>.b syntax;
  1780 
  1781 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1782 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1783 
  1784 
  1785 *** FOL and ZF ***
  1786 
  1787 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1788   with `addloop' of the simplifier to faciliate case splitting in premises.
  1789 
  1790 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1791 in HOL, they strip ALL and --> from proved theorems;
  1792 
  1793 
  1794 
  1795 New in Isabelle94-8 (May 1997)
  1796 ------------------------------
  1797 
  1798 *** General Changes ***
  1799 
  1800 * new utilities to build / run / maintain Isabelle etc. (in parts
  1801 still somewhat experimental); old Makefiles etc. still functional;
  1802 
  1803 * new 'Isabelle System Manual';
  1804 
  1805 * INSTALL text, together with ./configure and ./build scripts;
  1806 
  1807 * reimplemented type inference for greater efficiency, better error
  1808 messages and clean internal interface;
  1809 
  1810 * prlim command for dealing with lots of subgoals (an easier way of
  1811 setting goals_limit);
  1812 
  1813 
  1814 *** Syntax ***
  1815 
  1816 * supports alternative (named) syntax tables (parser and pretty
  1817 printer); internal interface is provided by add_modesyntax(_i);
  1818 
  1819 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1820 be used in conjunction with the Isabelle symbol font; uses the
  1821 "symbols" syntax table;
  1822 
  1823 * added token_translation interface (may translate name tokens in
  1824 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1825 the current print_mode); IMPORTANT: user print translation functions
  1826 are responsible for marking newly introduced bounds
  1827 (Syntax.mark_boundT);
  1828 
  1829 * token translations for modes "xterm" and "xterm_color" that display
  1830 names in bold, underline etc. or colors (which requires a color
  1831 version of xterm);
  1832 
  1833 * infixes may now be declared with names independent of their syntax;
  1834 
  1835 * added typed_print_translation (like print_translation, but may
  1836 access type of constant);
  1837 
  1838 
  1839 *** Classical Reasoner ***
  1840 
  1841 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1842 some limitations.  Blast_tac...
  1843   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1844   + ignores elimination rules that don't have the correct format
  1845         (the conclusion MUST be a formula variable)
  1846   + ignores types, which can make HOL proofs fail
  1847   + rules must not require higher-order unification, e.g. apply_type in ZF
  1848     [message "Function Var's argument not a bound variable" relates to this]
  1849   + its proof strategy is more general but can actually be slower
  1850 
  1851 * substitution with equality assumptions no longer permutes other
  1852 assumptions;
  1853 
  1854 * minor changes in semantics of addafter (now called addaltern); renamed
  1855 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1856 (and access functions for it);
  1857 
  1858 * improved combination of classical reasoner and simplifier:
  1859   + functions for handling clasimpsets
  1860   + improvement of addss: now the simplifier is called _after_ the
  1861     safe steps.
  1862   + safe variant of addss called addSss: uses safe simplifications
  1863     _during_ the safe steps. It is more complete as it allows multiple
  1864     instantiations of unknowns (e.g. with slow_tac).
  1865 
  1866 *** Simplifier ***
  1867 
  1868 * added interface for simplification procedures (functions that
  1869 produce *proven* rewrite rules on the fly, depending on current
  1870 redex);
  1871 
  1872 * ordering on terms as parameter (used for ordered rewriting);
  1873 
  1874 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1875 
  1876 * the solver is now split into a safe and an unsafe part.
  1877 This should be invisible for the normal user, except that the
  1878 functions setsolver and addsolver have been renamed to setSolver and
  1879 addSolver; added safe_asm_full_simp_tac;
  1880 
  1881 
  1882 *** HOL ***
  1883 
  1884 * a generic induction tactic `induct_tac' which works for all datatypes and
  1885 also for type `nat';
  1886 
  1887 * a generic case distinction tactic `exhaust_tac' which works for all
  1888 datatypes and also for type `nat';
  1889 
  1890 * each datatype comes with a function `size';
  1891 
  1892 * patterns in case expressions allow tuple patterns as arguments to
  1893 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1894 
  1895 * primrec now also works with type nat;
  1896 
  1897 * recdef: a new declaration form, allows general recursive functions to be
  1898 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1899 
  1900 * the constant for negation has been renamed from "not" to "Not" to
  1901 harmonize with FOL, ZF, LK, etc.;
  1902 
  1903 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1904 infinite lists;
  1905 
  1906 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1907 
  1908 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1909 problems in commutative rings, using axiomatic type classes for + and *;
  1910 
  1911 * more examples in HOL/MiniML and HOL/Auth;
  1912 
  1913 * more default rewrite rules for quantifiers, union/intersection;
  1914 
  1915 * a new constant `arbitrary == @x.False';
  1916 
  1917 * HOLCF/IOA replaces old HOL/IOA;
  1918 
  1919 * HOLCF changes: derived all rules and arities
  1920   + axiomatic type classes instead of classes
  1921   + typedef instead of faking type definitions
  1922   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1923   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1924   + eliminated the types void, one, tr
  1925   + use unit lift and bool lift (with translations) instead of one and tr
  1926   + eliminated blift from Lift3.thy (use Def instead of blift)
  1927   all eliminated rules are derived as theorems --> no visible changes ;
  1928 
  1929 
  1930 *** ZF ***
  1931 
  1932 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1933 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1934 as ZF_cs addSIs [equalityI];
  1935 
  1936 
  1937 
  1938 New in Isabelle94-7 (November 96)
  1939 ---------------------------------
  1940 
  1941 * allowing negative levels (as offsets) in prlev and choplev;
  1942 
  1943 * super-linear speedup for large simplifications;
  1944 
  1945 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1946 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1947 FAIL); can suppress it using the command Delsimps (ex_simps @
  1948 all_simps); De Morgan laws are also now included, by default;
  1949 
  1950 * improved printing of ==>  :  ~:
  1951 
  1952 * new object-logic "Sequents" adds linear logic, while replacing LK
  1953 and Modal (thanks to Sara Kalvala);
  1954 
  1955 * HOL/Auth: correctness proofs for authentication protocols;
  1956 
  1957 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1958 examples on HOL/Auth);
  1959 
  1960 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1961 the rewriter and classical reasoner simultaneously;
  1962 
  1963 * function uresult no longer returns theorems in "standard" format;
  1964 regain previous version by: val uresult = standard o uresult;
  1965 
  1966 
  1967 
  1968 New in Isabelle94-6
  1969 -------------------
  1970 
  1971 * oracles -- these establish an interface between Isabelle and trusted
  1972 external reasoners, which may deliver results as theorems;
  1973 
  1974 * proof objects (in particular record all uses of oracles);
  1975 
  1976 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1977 
  1978 * "constdefs" section in theory files;
  1979 
  1980 * "primrec" section (HOL) no longer requires names;
  1981 
  1982 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1983 
  1984 
  1985 
  1986 New in Isabelle94-5
  1987 -------------------
  1988 
  1989 * reduced space requirements;
  1990 
  1991 * automatic HTML generation from theories;
  1992 
  1993 * theory files no longer require "..." (quotes) around most types;
  1994 
  1995 * new examples, including two proofs of the Church-Rosser theorem;
  1996 
  1997 * non-curried (1994) version of HOL is no longer distributed;
  1998 
  1999 
  2000 
  2001 New in Isabelle94-4
  2002 -------------------
  2003 
  2004 * greatly reduced space requirements;
  2005 
  2006 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2007 
  2008 * searchable theorem database (see the section "Retrieving theorems" on
  2009 page 8 of the Reference Manual);
  2010 
  2011 * new examples, including Grabczewski's monumental case study of the
  2012 Axiom of Choice;
  2013 
  2014 * The previous version of HOL renamed to Old_HOL;
  2015 
  2016 * The new version of HOL (previously called CHOL) uses a curried syntax
  2017 for functions.  Application looks like f a b instead of f(a,b);
  2018 
  2019 * Mutually recursive inductive definitions finally work in HOL;
  2020 
  2021 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2022 translates to the operator "split";
  2023 
  2024 
  2025 
  2026 New in Isabelle94-3
  2027 -------------------
  2028 
  2029 * new infix operator, addss, allowing the classical reasoner to
  2030 perform simplification at each step of its search.  Example:
  2031         fast_tac (cs addss ss)
  2032 
  2033 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2034 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2035 look like (a,b) instead of <a,b>;
  2036 
  2037 * PLEASE NOTE: CHOL will eventually replace HOL!
  2038 
  2039 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2040 It translates to the operator "split".  A new theory of integers is available;
  2041 
  2042 * In ZF, integer numerals now denote two's-complement binary integers.
  2043 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2044 
  2045 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2046 of the Axiom of Choice;
  2047 
  2048 
  2049 
  2050 New in Isabelle94-2
  2051 -------------------
  2052 
  2053 * Significantly faster resolution;
  2054 
  2055 * the different sections in a .thy file can now be mixed and repeated
  2056 freely;
  2057 
  2058 * Database of theorems for FOL, HOL and ZF.  New
  2059 commands including qed, qed_goal and bind_thm store theorems in the database.
  2060 
  2061 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2062 a given theory (thms_of), or find out what theory a theorem was proved in
  2063 (theory_of_thm);
  2064 
  2065 * Bugs fixed in the inductive definition and datatype packages;
  2066 
  2067 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2068 and HOL_dup_cs obsolete;
  2069 
  2070 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2071 have been removed;
  2072 
  2073 * Simpler definition of function space in ZF;
  2074 
  2075 * new results about cardinal and ordinal arithmetic in ZF;
  2076 
  2077 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2078 types;
  2079 
  2080 
  2081 $Id$