NEWS
author wenzelm
Tue Nov 20 22:53:05 2001 +0100 (2001-11-20)
changeset 12253 1886dc96b7e9
parent 12245 3dd9aae402bb
child 12280 fc7e3f01bc40
permissions -rw-r--r--
* HOL/record: cases/induct for more parts;
* syntax: prefer later print_translation functions;
     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 * improved proof by cases and induction:
    36   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    37   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    38   - moved induct/cases attributes to Pure, methods to Provers;
    39   - generic method setup instantiated for FOL and HOL;
    40 
    41   - 'case' command admits impromptu naming of parameters (such as
    42 "case (Suc n)");
    43 
    44   - 'induct' method divinates rule instantiation from the inductive
    45 claim; no longer requires excessive ?P bindings for proper
    46 instantiation of cases;
    47 
    48   - 'induct' method properly enumerates all possibilities of set/type
    49 rules; as a consequence facts may be also passed through *type* rules
    50 without further ado;
    51 
    52   - 'induct' method now derives symbolic cases from the *rulified*
    53 rule (before it used to rulify cases stemming from the internal
    54 atomized version); this means that the context of a non-atomic
    55 statement becomes is included in the hypothesis, avoiding the slightly
    56 cumbersome show "PROP ?case" form;
    57 
    58   - 'induct' may now use elim-style induction rules without chaining
    59 facts, using ``missing'' premises from the goal state; this allows
    60 rules stemming from inductive sets to be applied in unstructured
    61 scripts, while still benefitting from proper handling of non-atomic
    62 statements; NB: major inductive premises need to be put first, all the
    63 rest of the goal is passed through the induction;
    64 
    65 - 'induct' proper support for mutual induction involving non-atomic
    66 rule statements (uses the new concept of simultaneous goals, see
    67 below);
    68 
    69 * Pure: support multiple simultaneous goal statements, for example
    70 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    71 meta-level mechanism, this acts as if several individual goals had
    72 been stated separately; in particular common proof methods need to be
    73 repeated in order to cover all claims; note that a single elimination
    74 step is *not* sufficient to establish the two conjunctions, so this
    75 fails:
    76 
    77   assume "A & B" then have A and B ..   (*".." fails*)
    78 
    79 better use "obtain" in situations as above; alternative refer to
    80 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    81 
    82 * Pure: proper integration with ``locales''; unlike the original
    83 version by Florian Kammüller, Isar locales package high-level proof
    84 contexts rather than raw logical ones (e.g. we admit to include
    85 attributes everywhere);
    86 
    87 * Pure: theory goals now support ad-hoc contexts, which are discharged
    88 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    89 coincides with that of a locale body;
    90 
    91 * Pure: renamed "antecedent" case to "rule_context";
    92 
    93 * Pure: added 'corollary' command;
    94 
    95 * Pure: fixed 'token_translation' command;
    96 
    97 * Pure: removed obsolete 'exported' attribute;
    98 
    99 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   100 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   101 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   102 
   103 * Pure: method 'atomize' presents local goal premises as object-level
   104 statements (atomic meta-level propositions); setup controlled via
   105 rewrite rules declarations of 'atomize' attribute; example
   106 application: 'induct' method with proper rule statements in improper
   107 proof *scripts*;
   108 
   109 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   110 now consider the syntactic context of assumptions, giving a better
   111 chance to get type-inference of the arguments right (this is
   112 especially important for locales);
   113 
   114 * Provers: 'simplified' attribute may refer to explicit rules instead
   115 of full simplifier context; 'iff' attribute handles conditional rules;
   116 
   117 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   118 
   119 * HOL: 'recdef' now fails on unfinished automated proofs, use
   120 "(permissive)" option to recover old behavior;
   121 
   122 * HOL: 'inductive' no longer features separate (collective) attributes
   123 for 'intros' (was found too confusing);
   124 
   125 
   126 
   127 *** HOL ***
   128 
   129 * HOL: moved over to sane numeral syntax; the new policy is as
   130 follows:
   131 
   132   - 0 and 1 are polymorphic constants, which are defined on any
   133   numeric type (nat, int, real etc.);
   134 
   135   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   136   binary representation internally;
   137 
   138   - type nat has special constructor Suc, and generally prefers Suc 0
   139   over 1::nat and Suc (Suc 0) over 2::nat;
   140 
   141 This change may cause significant INCOMPATIBILITIES; here are some
   142 hints on converting existing sources:
   143 
   144   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   145   entities, so expressions involving "-" (unary or binary minus) need
   146   to be spaced properly;
   147 
   148   - existing occurrences of "1" may need to be constraint "1::nat" or
   149   even replaced by Suc 0; similar for old "2";
   150 
   151   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   152 
   153   - remove all special provisions on numerals in proofs;
   154 
   155 * HOL/record:
   156   - removed old "make" and "make_scheme" operations -- INCOMPATIBILITY;
   157   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   158   - provides cases/induct rules for use with corresponding Isar
   159     methods (for concrete records, record schemes, concrete more
   160     parts, schematic more parts -- in that order);
   161   - new derived operations "make" (for adding fields of current
   162     record), "extend" to promote fixed record to record scheme, and
   163     "truncate" for the reverse; cf. theorems "derived_defs", which are
   164     *not* declared as simp by default;
   165   - internal definitions directly based on a light-weight abstract
   166     theory of product types over typedef rather than datatype;
   167 
   168 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   169 
   170 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   171 (beware of argument permutation!);
   172 
   173 * HOL: linorder_less_split superseded by linorder_cases;
   174 
   175 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   176 to peripheral theory "Hilbert_Choice";
   177 
   178 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   179 in this (rare) case use:
   180 
   181   delSWrapper "split_all_tac"
   182   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   183 
   184 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   185 MAY FAIL;
   186 
   187 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   188 Isabelle's type classes, ^ on functions and relations has too general
   189 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   190 necessary to attach explicit type constraints;
   191 
   192 * HOL: syntax translations now work properly with numerals and records
   193 expressions;
   194 
   195 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   196 Florian Kammüller;
   197 
   198 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   199 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   200 renamed "Product_Type.unit";
   201 
   202 
   203 *** HOLCF ***
   204 
   205 * proper rep_datatype lift (see theory Lift); use plain induct_tac
   206 instead of former lift.induct_tac; always use UU instead of Undef;
   207 
   208 * 'domain' package adapted to new-style theories, e.g. see
   209 HOLCF/ex/Dnat.thy;
   210 
   211 
   212 *** ZF ***
   213 
   214 * ZF: new-style theory commands '(co)inductive', '(co)datatype',
   215 'rep_datatype', 'inductive_cases'; also methods 'ind_cases',
   216 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   217 
   218 * ZF: the integer library now covers quotients and remainders, with
   219 many laws relating division to addition, multiplication, etc.;
   220 
   221 * ZF/Induct: new directory for examples of inductive definitions,
   222 including theory Multiset for multiset orderings;
   223 
   224 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   225 typeless version of the formalism;
   226 
   227 
   228 *** General ***
   229 
   230 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   231 manual;
   232 
   233 * Pure/axclass: removed obsolete ML interface goal_subclass/goal_arity;
   234 
   235 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   236 
   237 * clasimp: ``iff'' declarations now handle conditional rules as well;
   238 
   239 * syntax: new token syntax "num" for plain numerals (without "#" of
   240 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   241 tokens, so expressions involving minus need to be spaced properly;
   242 
   243 * syntax: support non-oriented infixes;
   244 
   245 * syntax: print modes "type_brackets" and "no_type_brackets" control
   246 output of nested => (types); the default behavior is "type_brackets";
   247 
   248 * syntax: builtin parse translation for "_constify" turns valued
   249 tokens into AST constants;
   250 
   251 * syntax: prefer later print_translation functions; potential
   252 INCOMPATIBILITY: need to reverse declarations of multiple translation
   253 functions for same constant;
   254 
   255 * system: refrain from any attempt at filtering input streams; no
   256 longer support ``8bit'' encoding of old isabelle font, instead proper
   257 iso-latin characters may now be used;
   258 
   259 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   260 
   261 * system: Proof General keywords specification is now part of the
   262 Isabelle distribution (see etc/isar-keywords.el);
   263 
   264 * system: smart selection of Isabelle process versus Isabelle
   265 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   266 run both "isabelle" and "Isabelle" even if file names are badly
   267 damaged (executable inspects the case of the first letter of its own
   268 name); added separate "isabelle-process" and "isabelle-interface";
   269 
   270 
   271 
   272 New in Isabelle99-2 (February 2001)
   273 -----------------------------------
   274 
   275 *** Overview of INCOMPATIBILITIES ***
   276 
   277 * HOL: please note that theories in the Library and elsewhere often use the
   278 new-style (Isar) format; to refer to their theorems in an ML script you must
   279 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   280 
   281 * HOL: inductive package no longer splits induction rule aggressively,
   282 but only as far as specified by the introductions given; the old
   283 format may be recovered via ML function complete_split_rule or attribute
   284 'split_rule (complete)';
   285 
   286 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   287 gfp_Tarski to gfp_unfold;
   288 
   289 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   290 
   291 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   292 relation); infix "^^" has been renamed "``"; infix "``" has been
   293 renamed "`"; "univalent" has been renamed "single_valued";
   294 
   295 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   296 operation;
   297 
   298 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   299 
   300 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   301 
   302 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   303 consequence, it is no longer monotonic wrt. the local goal context
   304 (which is now passed through the inductive cases);
   305 
   306 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   307 \<gg> to \<ggreater>;
   308 
   309 
   310 *** Document preparation ***
   311 
   312 * \isabellestyle{NAME} selects version of Isabelle output (currently
   313 available: are "it" for near math-mode best-style output, "sl" for
   314 slanted text style, and "tt" for plain type-writer; if no
   315 \isabellestyle command is given, output is according to slanted
   316 type-writer);
   317 
   318 * support sub/super scripts (for single symbols only), input syntax is
   319 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   320 
   321 * some more standard symbols; see Appendix A of the system manual for
   322 the complete list of symbols defined in isabellesym.sty;
   323 
   324 * improved isabelle style files; more abstract symbol implementation
   325 (should now use \isamath{...} and \isatext{...} in custom symbol
   326 definitions);
   327 
   328 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   329 state; Note that presentation of goal states does not conform to
   330 actual human-readable proof documents.  Please do not include goal
   331 states into document output unless you really know what you are doing!
   332 
   333 * proper indentation of antiquoted output with proportional LaTeX
   334 fonts;
   335 
   336 * no_document ML operator temporarily disables LaTeX document
   337 generation;
   338 
   339 * isatool unsymbolize tunes sources for plain ASCII communication;
   340 
   341 
   342 *** Isar ***
   343 
   344 * Pure: Isar now suffers initial goal statements to contain unbound
   345 schematic variables (this does not conform to actual readable proof
   346 documents, due to unpredictable outcome and non-compositional proof
   347 checking); users who know what they are doing may use schematic goals
   348 for Prolog-style synthesis of proven results;
   349 
   350 * Pure: assumption method (an implicit finishing) now handles actual
   351 rules as well;
   352 
   353 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   354 initial goal, declare "that" only as Pure intro (only for single
   355 steps); the "that" rule assumption may now be involved in implicit
   356 finishing, thus ".." becomes a feasible for trivial obtains;
   357 
   358 * Pure: default proof step now includes 'intro_classes'; thus trivial
   359 instance proofs may be performed by "..";
   360 
   361 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   362 statements as well;
   363 
   364 * Pure: more robust selection of calculational rules;
   365 
   366 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   367 rule (as well as the assumption rule);
   368 
   369 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   370 lemmas, using the graph browser tool;
   371 
   372 * Pure: predict failure of "show" in interactive mode;
   373 
   374 * Pure: 'thms_containing' now takes actual terms as arguments;
   375 
   376 * HOL: improved method 'induct' --- now handles non-atomic goals
   377 (potential INCOMPATIBILITY); tuned error handling;
   378 
   379 * HOL: cases and induct rules now provide explicit hints about the
   380 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   381 any remaining facts are inserted into the goal verbatim;
   382 
   383 * HOL: local contexts (aka cases) may now contain term bindings as
   384 well; the 'cases' and 'induct' methods new provide a ?case binding for
   385 the result to be shown in each case;
   386 
   387 * HOL: added 'recdef_tc' command;
   388 
   389 * isatool convert assists in eliminating legacy ML scripts;
   390 
   391 
   392 *** HOL ***
   393 
   394 * HOL/Library: a collection of generic theories to be used together
   395 with main HOL; the theory loader path already includes this directory
   396 by default; the following existing theories have been moved here:
   397 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   398 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   399 
   400 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   401 modelling and verification task performed in Isabelle/HOL +
   402 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   403 
   404 * HOL/Algebra: special summation operator SUM no longer exists, it has
   405 been replaced by setsum; infix 'assoc' now has priority 50 (like
   406 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   407 'domain', this makes the theory consistent with mathematical
   408 literature;
   409 
   410 * HOL basics: added overloaded operations "inverse" and "divide"
   411 (infix "/"), syntax for generic "abs" operation, generic summation
   412 operator \<Sum>;
   413 
   414 * HOL/typedef: simplified package, provide more useful rules (see also
   415 HOL/subset.thy);
   416 
   417 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   418 now expressed as a proper nested rule (old-style tactic scripts may
   419 require atomize_strip_tac to cope with non-atomic premises);
   420 
   421 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   422 to "split_conv" (old name still available for compatibility);
   423 
   424 * HOL: improved concrete syntax for strings (e.g. allows translation
   425 rules with string literals);
   426 
   427 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   428  and Fleuriot's mechanization of analysis, including the transcendental
   429  functions for the reals;
   430 
   431 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   432 
   433 
   434 *** CTT ***
   435 
   436 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   437 "lam" is displayed as TWO lambda-symbols
   438 
   439 * CTT: theory Main now available, containing everything (that is, Bool
   440 and Arith);
   441 
   442 
   443 *** General ***
   444 
   445 * Pure: the Simplifier has been implemented properly as a derived rule
   446 outside of the actual kernel (at last!); the overall performance
   447 penalty in practical applications is about 50%, while reliability of
   448 the Isabelle inference kernel has been greatly improved;
   449 
   450 * print modes "brackets" and "no_brackets" control output of nested =>
   451 (types) and ==> (props); the default behaviour is "brackets";
   452 
   453 * Provers: fast_tac (and friends) now handle actual object-logic rules
   454 as assumptions as well;
   455 
   456 * system: support Poly/ML 4.0;
   457 
   458 * system: isatool install handles KDE version 1 or 2;
   459 
   460 
   461 
   462 New in Isabelle99-1 (October 2000)
   463 ----------------------------------
   464 
   465 *** Overview of INCOMPATIBILITIES ***
   466 
   467 * HOL: simplification of natural numbers is much changed; to partly
   468 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   469 issue the following ML commands:
   470 
   471   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   472   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   473 
   474 * HOL: simplification no longer dives into case-expressions; this is
   475 controlled by "t.weak_case_cong" for each datatype t;
   476 
   477 * HOL: nat_less_induct renamed to less_induct;
   478 
   479 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   480 fixsome to patch .thy and .ML sources automatically;
   481 
   482   select_equality  -> some_equality
   483   select_eq_Ex     -> some_eq_ex
   484   selectI2EX       -> someI2_ex
   485   selectI2         -> someI2
   486   selectI          -> someI
   487   select1_equality -> some1_equality
   488   Eps_sym_eq       -> some_sym_eq_trivial
   489   Eps_eq           -> some_eq_trivial
   490 
   491 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   492 
   493 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   494 instead);
   495 
   496 * HOL: the recursion equations generated by 'recdef' are now called
   497 f.simps instead of f.rules;
   498 
   499 * HOL: qed_spec_mp now also handles bounded ALL as well;
   500 
   501 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   502 sometimes be needed;
   503 
   504 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   505 
   506 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   507 
   508 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   509 product is now "<*>" instead of "Times"; the lexicographic product is
   510 now "<*lex*>" instead of "**";
   511 
   512 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   513 of main HOL, but was unused); better use HOL's datatype package;
   514 
   515 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   516 the old syntax may be recovered as follows:
   517 
   518   syntax (symbols)
   519     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   520       (infixl "\\<oplus>" 100)
   521 
   522 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   523 
   524 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   525 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   526 internally;
   527 
   528 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   529 changed from A/r to A//r;
   530 
   531 * ZF: new treatment of arithmetic (nat & int) may break some old
   532 proofs;
   533 
   534 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   535 rulify -> rule_format, elimify -> elim_format, ...);
   536 
   537 * Isar/Provers: intro/elim/dest attributes changed; renamed
   538 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   539 should have to change intro!! to intro? only); replaced "delrule" by
   540 "rule del";
   541 
   542 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   543 
   544 * Provers: strengthened force_tac by using new first_best_tac;
   545 
   546 * LaTeX document preparation: several changes of isabelle.sty (see
   547 lib/texinputs);
   548 
   549 
   550 *** Document preparation ***
   551 
   552 * formal comments (text blocks etc.) in new-style theories may now
   553 contain antiquotations of thm/prop/term/typ/text to be presented
   554 according to latex print mode; concrete syntax is like this:
   555 @{term[show_types] "f(x) = a + x"};
   556 
   557 * isatool mkdir provides easy setup of Isabelle session directories,
   558 including proper document sources;
   559 
   560 * generated LaTeX sources are now deleted after successful run
   561 (isatool document -c); may retain a copy somewhere else via -D option
   562 of isatool usedir;
   563 
   564 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   565 style files, achieving self-contained LaTeX sources and simplifying
   566 LaTeX debugging;
   567 
   568 * old-style theories now produce (crude) LaTeX output as well;
   569 
   570 * browser info session directories are now self-contained (may be put
   571 on WWW server seperately); improved graphs of nested sessions; removed
   572 graph for 'all sessions';
   573 
   574 * several improvements in isabelle style files; \isabellestyle{it}
   575 produces fake math mode output; \isamarkupheader is now \section by
   576 default; see lib/texinputs/isabelle.sty etc.;
   577 
   578 
   579 *** Isar ***
   580 
   581 * Isar/Pure: local results and corresponding term bindings are now
   582 subject to Hindley-Milner polymorphism (similar to ML); this
   583 accommodates incremental type-inference very nicely;
   584 
   585 * Isar/Pure: new derived language element 'obtain' supports
   586 generalized existence reasoning;
   587 
   588 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   589 support accumulation of results, without applying any rules yet;
   590 useful to collect intermediate results without explicit name
   591 references, and for use with transitivity rules with more than 2
   592 premises;
   593 
   594 * Isar/Pure: scalable support for case-analysis type proofs: new
   595 'case' language element refers to local contexts symbolically, as
   596 produced by certain proof methods; internally, case names are attached
   597 to theorems as "tags";
   598 
   599 * Isar/Pure: theory command 'hide' removes declarations from
   600 class/type/const name spaces;
   601 
   602 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   603 indicate potential overloading;
   604 
   605 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   606 
   607 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   608 "{a,b,c}" instead of {a,b,c};
   609 
   610 * Isar/Pure now provides its own version of intro/elim/dest
   611 attributes; useful for building new logics, but beware of confusion
   612 with the version in Provers/classical;
   613 
   614 * Isar/Pure: the local context of (non-atomic) goals is provided via
   615 case name 'antecedent';
   616 
   617 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   618 to the current context is now done automatically);
   619 
   620 * Isar/Pure: theory command 'method_setup' provides a simple interface
   621 for definining proof methods in ML;
   622 
   623 * Isar/Provers: intro/elim/dest attributes changed; renamed
   624 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   625 most cases, one should have to change intro!! to intro? only);
   626 replaced "delrule" by "rule del";
   627 
   628 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   629 'symmetric' attribute (the latter supercedes [RS sym]);
   630 
   631 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   632 method modifier); 'simp' method: 'only:' modifier removes loopers as
   633 well (including splits);
   634 
   635 * Isar/Provers: Simplifier and Classical methods now support all kind
   636 of modifiers used in the past, including 'cong', 'iff', etc.
   637 
   638 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   639 of Simplifier and Classical reasoner);
   640 
   641 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   642 now support named cases; major packages (inductive, datatype, primrec,
   643 recdef) support case names and properly name parameters;
   644 
   645 * Isar/HOL: new transitivity rules for substitution in inequalities --
   646 monotonicity conditions are extracted to be proven at end of
   647 calculations;
   648 
   649 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   650 method anyway;
   651 
   652 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   653 split_if split_if_asm; datatype package provides theorems foo.splits =
   654 foo.split foo.split_asm for each datatype;
   655 
   656 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   657 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   658 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   659 use "(cases (simplified))" method in proper proof texts);
   660 
   661 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   662 
   663 * Isar: names of theorems etc. may be natural numbers as well;
   664 
   665 * Isar: 'pr' command: optional arguments for goals_limit and
   666 ProofContext.prems_limit; no longer prints theory contexts, but only
   667 proof states;
   668 
   669 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   670 additional print modes to be specified; e.g. "pr(latex)" will print
   671 proof state according to the Isabelle LaTeX style;
   672 
   673 * Isar: improved support for emulating tactic scripts, including proof
   674 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   675 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   676 (for HOL datatypes);
   677 
   678 * Isar: simplified (more robust) goal selection of proof methods: 1st
   679 goal, all goals, or explicit goal specifier (tactic emulation); thus
   680 'proof method scripts' have to be in depth-first order;
   681 
   682 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   683 
   684 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   685 should instead use individual commands for printing items
   686 (print_commands, print_methods etc.);
   687 
   688 * Isar: added 'nothing' --- the empty list of theorems;
   689 
   690 
   691 *** HOL ***
   692 
   693 * HOL/MicroJava: formalization of a fragment of Java, together with a
   694 corresponding virtual machine and a specification of its bytecode
   695 verifier and a lightweight bytecode verifier, including proofs of
   696 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   697 Cornelia Pusch (see also the homepage of project Bali at
   698 http://isabelle.in.tum.de/Bali/);
   699 
   700 * HOL/Algebra: new theory of rings and univariate polynomials, by
   701 Clemens Ballarin;
   702 
   703 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   704 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   705 Rasmussen;
   706 
   707 * HOL/Lattice: fundamental concepts of lattice theory and order
   708 structures, including duals, properties of bounds versus algebraic
   709 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   710 Theorem for complete lattices etc.; may also serve as a demonstration
   711 for abstract algebraic reasoning using axiomatic type classes, and
   712 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   713 
   714 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   715 von Oheimb;
   716 
   717 * HOL/IMPP: extension of IMP with local variables and mutually
   718 recursive procedures, by David von Oheimb;
   719 
   720 * HOL/Lambda: converted into new-style theory and document;
   721 
   722 * HOL/ex/Multiquote: example of multiple nested quotations and
   723 anti-quotations -- basically a generalized version of de-Bruijn
   724 representation; very useful in avoiding lifting of operations;
   725 
   726 * HOL/record: added general record equality rule to simpset; fixed
   727 select-update simplification procedure to handle extended records as
   728 well; admit "r" as field name;
   729 
   730 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   731 other numeric types and also as the identity of groups, rings, etc.;
   732 
   733 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   734 Types nat and int belong to this axclass;
   735 
   736 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   737    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   738    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   739   two terms #m*u and #n*u are replaced by #(m+n)*u
   740     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   741   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   742     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   743 
   744 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   745 powerful prover for predicate logic but knows nothing of clasets; see
   746 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   747 
   748 * HOL: new version of "case_tac" subsumes both boolean case split and
   749 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   750 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   751 
   752 * HOL: simplification no longer dives into case-expressions: only the
   753 selector expression is simplified, but not the remaining arms; to
   754 enable full simplification of case-expressions for datatype t, you may
   755 remove t.weak_case_cong from the simpset, either globally (Delcongs
   756 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   757 
   758 * HOL/recdef: the recursion equations generated by 'recdef' for
   759 function 'f' are now called f.simps instead of f.rules; if all
   760 termination conditions are proved automatically, these simplification
   761 rules are added to the simpset, as in primrec; rules may be named
   762 individually as well, resulting in a separate list of theorems for
   763 each equation;
   764 
   765 * HOL/While is a new theory that provides a while-combinator. It
   766 permits the definition of tail-recursive functions without the
   767 provision of a termination measure. The latter is necessary once the
   768 invariant proof rule for while is applied.
   769 
   770 * HOL: new (overloaded) notation for the set of elements below/above
   771 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   772 
   773 * HOL: theorems impI, allI, ballI bound as "strip";
   774 
   775 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   776 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   777 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   778 
   779 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   780 
   781 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   782 main HOL, but was unused);
   783 
   784 * HOL: fewer consts declared as global (e.g. have to refer to
   785 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   786 
   787 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   788 in case of overlap with user translations (e.g. judgements over
   789 tuples); (note that the underlying logical represenation is still
   790 bogus);
   791 
   792 
   793 *** ZF ***
   794 
   795 * ZF: simplification automatically cancels common terms in arithmetic
   796 expressions over nat and int;
   797 
   798 * ZF: new treatment of nat to minimize type-checking: all operators
   799 coerce their operands to a natural number using the function natify,
   800 making the algebraic laws unconditional;
   801 
   802 * ZF: as above, for int: operators coerce their operands to an integer
   803 using the function intify;
   804 
   805 * ZF: the integer library now contains many of the usual laws for the
   806 orderings, including $<=, and monotonicity laws for $+ and $*;
   807 
   808 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   809 simplification;
   810 
   811 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   812 to the simplifier and classical reasoner simultaneously;
   813 
   814 
   815 *** General ***
   816 
   817 * Provers: blast_tac now handles actual object-logic rules as
   818 assumptions; note that auto_tac uses blast_tac internally as well;
   819 
   820 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   821 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   822 
   823 * Provers: delrules now handles destruct rules as well (no longer need
   824 explicit make_elim);
   825 
   826 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   827   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   828 use instead the strong form,
   829   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   830 in HOL, FOL and ZF the function cla_make_elim will create such rules
   831 from destruct-rules;
   832 
   833 * Provers: Simplifier.easy_setup provides a fast path to basic
   834 Simplifier setup for new object-logics;
   835 
   836 * Pure: AST translation rules no longer require constant head on LHS;
   837 
   838 * Pure: improved name spaces: ambiguous output is qualified; support
   839 for hiding of names;
   840 
   841 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   842 XSYMBOL_HOME; no longer need to do manual configuration in most
   843 situations;
   844 
   845 * system: compression of ML heaps images may now be controlled via -c
   846 option of isabelle and isatool usedir (currently only observed by
   847 Poly/ML);
   848 
   849 * system: isatool installfonts may handle X-Symbol fonts as well (very
   850 useful for remote X11);
   851 
   852 * system: provide TAGS file for Isabelle sources;
   853 
   854 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   855 order;
   856 
   857 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   858 timing flag supersedes proof_timing and Toplevel.trace;
   859 
   860 * ML: new combinators |>> and |>>> for incremental transformations
   861 with secondary results (e.g. certain theory extensions):
   862 
   863 * ML: PureThy.add_defs gets additional argument to indicate potential
   864 overloading (usually false);
   865 
   866 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   867 results;
   868 
   869 
   870 
   871 New in Isabelle99 (October 1999)
   872 --------------------------------
   873 
   874 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   875 
   876 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   877 are no longer simplified.  (This allows the simplifier to unfold recursive
   878 functional programs.)  To restore the old behaviour, declare
   879 
   880     Delcongs [if_weak_cong];
   881 
   882 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   883 complement;
   884 
   885 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   886 
   887 * HOL/datatype: mutual_induct_tac no longer exists --
   888   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   889 
   890 * HOL/typedef: fixed type inference for representing set; type
   891 arguments now have to occur explicitly on the rhs as type constraints;
   892 
   893 * ZF: The con_defs part of an inductive definition may no longer refer
   894 to constants declared in the same theory;
   895 
   896 * HOL, ZF: the function mk_cases, generated by the inductive
   897 definition package, has lost an argument.  To simplify its result, it
   898 uses the default simpset instead of a supplied list of theorems.
   899 
   900 * HOL/List: the constructors of type list are now Nil and Cons;
   901 
   902 * Simplifier: the type of the infix ML functions
   903         setSSolver addSSolver setSolver addSolver
   904 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   905 for packaging solvers. A solver is created via
   906         mk_solver: string -> (thm list -> int -> tactic) -> solver
   907 where the string argument is only a comment.
   908 
   909 
   910 *** Proof tools ***
   911 
   912 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   913 decision procedure for linear arithmetic. Currently it is used for
   914 types `nat', `int', and `real' in HOL (see below); it can, should and
   915 will be instantiated for other types and logics as well.
   916 
   917 * The simplifier now accepts rewrite rules with flexible heads, eg
   918      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   919   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   920   matching.
   921 
   922 
   923 *** General ***
   924 
   925 * New Isabelle/Isar subsystem provides an alternative to traditional
   926 tactical theorem proving; together with the ProofGeneral/isar user
   927 interface it offers an interactive environment for developing human
   928 readable proof documents (Isar == Intelligible semi-automated
   929 reasoning); for further information see isatool doc isar-ref,
   930 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   931 
   932 * improved and simplified presentation of theories: better HTML markup
   933 (including colors), graph views in several sizes; isatool usedir now
   934 provides a proper interface for user theories (via -P option); actual
   935 document preparation based on (PDF)LaTeX is available as well (for
   936 new-style theories only); see isatool doc system for more information;
   937 
   938 * native support for Proof General, both for classic Isabelle and
   939 Isabelle/Isar;
   940 
   941 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   942 using the graph browser tool;
   943 
   944 * Isabelle manuals now also available as PDF;
   945 
   946 * theory loader rewritten from scratch (may not be fully
   947 bug-compatible); old loadpath variable has been replaced by show_path,
   948 add_path, del_path, reset_path functions; new operations such as
   949 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   950 isatool doc ref);
   951 
   952 * improved isatool install: option -k creates KDE application icon,
   953 option -p DIR installs standalone binaries;
   954 
   955 * added ML_PLATFORM setting (useful for cross-platform installations);
   956 more robust handling of platform specific ML images for SML/NJ;
   957 
   958 * the settings environment is now statically scoped, i.e. it is never
   959 created again in sub-processes invoked from isabelle, isatool, or
   960 Isabelle;
   961 
   962 * path element specification '~~' refers to '$ISABELLE_HOME';
   963 
   964 * in locales, the "assumes" and "defines" parts may be omitted if
   965 empty;
   966 
   967 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   968 long arrows);
   969 
   970 * new print_mode "HTML";
   971 
   972 * new flag show_tags controls display of tags of theorems (which are
   973 basically just comments that may be attached by some tools);
   974 
   975 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   976 mode and goal output format:
   977 
   978 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   979 244c244
   980 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   981 ---
   982 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   983 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   984 181c181
   985 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   986 ---
   987 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   988 
   989 * function bind_thms stores lists of theorems (cf. bind_thm);
   990 
   991 * new shorthand tactics ftac, eatac, datac, fatac;
   992 
   993 * qed (and friends) now accept "" as result name; in that case the
   994 theorem is not stored, but proper checks and presentation of the
   995 result still apply;
   996 
   997 * theorem database now also indexes constants "Trueprop", "all",
   998 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   999 
  1000 
  1001 *** HOL ***
  1002 
  1003 ** HOL arithmetic **
  1004 
  1005 * There are now decision procedures for linear arithmetic over nat and
  1006 int:
  1007 
  1008 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1009 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1010 are treated as atomic; subformulae not involving type `nat' or `int'
  1011 are ignored; quantified subformulae are ignored unless they are
  1012 positive universal or negative existential. The tactic has to be
  1013 invoked by hand and can be a little bit slow. In particular, the
  1014 running time is exponential in the number of occurrences of `min' and
  1015 `max', and `-' on `nat'.
  1016 
  1017 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1018 (negated) (in)equalities among the premises and the conclusion into
  1019 account (i.e. no compound formulae) and does not know about `min' and
  1020 `max', and `-' on `nat'. It is fast and is used automatically by the
  1021 simplifier.
  1022 
  1023 NB: At the moment, these decision procedures do not cope with mixed
  1024 nat/int formulae where the two parts interact, such as `m < n ==>
  1025 int(m) < int(n)'.
  1026 
  1027 * HOL/Numeral provides a generic theory of numerals (encoded
  1028 efficiently as bit strings); setup for types nat/int/real is in place;
  1029 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1030 int, existing theories and proof scripts may require a few additional
  1031 type constraints;
  1032 
  1033 * integer division and remainder can now be performed on constant
  1034 arguments;
  1035 
  1036 * many properties of integer multiplication, division and remainder
  1037 are now available;
  1038 
  1039 * An interface to the Stanford Validity Checker (SVC) is available through the
  1040 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1041 are proved automatically.  SVC must be installed separately, and its results
  1042 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1043 invocation of the underlying oracle).  For SVC see
  1044   http://verify.stanford.edu/SVC
  1045 
  1046 * IsaMakefile: the HOL-Real target now builds an actual image;
  1047 
  1048 
  1049 ** HOL misc **
  1050 
  1051 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1052 (in Isabelle/Isar) -- by Gertrud Bauer;
  1053 
  1054 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1055 analysis for assembly languages with subtypes;
  1056 
  1057 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1058 -- avoids syntactic ambiguities and treats state, transition, and
  1059 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1060 changed syntax and (many) tactics;
  1061 
  1062 * HOL/inductive: Now also handles more general introduction rules such
  1063   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1064   theorems are now maintained within the theory (maintained via the
  1065   "mono" attribute);
  1066 
  1067 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1068   (using function types) such as
  1069 
  1070   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1071 
  1072 * HOL/record: record_simproc (part of the default simpset) takes care
  1073 of selectors applied to updated records; record_split_tac is no longer
  1074 part of the default claset; update_defs may now be removed from the
  1075 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1076 
  1077   claset_ref () := claset() addSWrapper record_split_wrapper;
  1078   Delsimprocs [record_simproc]
  1079 
  1080 * HOL/typedef: fixed type inference for representing set; type
  1081 arguments now have to occur explicitly on the rhs as type constraints;
  1082 
  1083 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1084 names rather than an ML expression;
  1085 
  1086 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1087 supplied later.  Program schemes can be defined, such as
  1088     "While B C s = (if B s then While B C (C s) else s)"
  1089 where the well-founded relation can be chosen after B and C have been given.
  1090 
  1091 * HOL/List: the constructors of type list are now Nil and Cons;
  1092 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1093 course, ML tools referring to List.list.op # etc. have to be adapted;
  1094 
  1095 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1096 disabled by default; run isabelle with option -m HOL to get back to
  1097 the original Gordon/HOL-style output;
  1098 
  1099 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1100 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1101 
  1102 * HOL basic syntax simplified (more orthogonal): all variants of
  1103 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1104 Eps operator is provided as well: "SOME x. P[x]";
  1105 
  1106 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1107 
  1108 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1109 thus available for user theories;
  1110 
  1111 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1112 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1113 time;
  1114 
  1115 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1116 several times and then mp;
  1117 
  1118 
  1119 *** LK ***
  1120 
  1121 * the notation <<...>> is now available as a notation for sequences of
  1122 formulas;
  1123 
  1124 * the simplifier is now installed
  1125 
  1126 * the axiom system has been generalized (thanks to Soren Heilmann)
  1127 
  1128 * the classical reasoner now has a default rule database
  1129 
  1130 
  1131 *** ZF ***
  1132 
  1133 * new primrec section allows primitive recursive functions to be given
  1134 directly (as in HOL) over datatypes and the natural numbers;
  1135 
  1136 * new tactics induct_tac and exhaust_tac for induction (or case
  1137 analysis) over datatypes and the natural numbers;
  1138 
  1139 * the datatype declaration of type T now defines the recursor T_rec;
  1140 
  1141 * simplification automatically does freeness reasoning for datatype
  1142 constructors;
  1143 
  1144 * automatic type-inference, with AddTCs command to insert new
  1145 type-checking rules;
  1146 
  1147 * datatype introduction rules are now added as Safe Introduction rules
  1148 to the claset;
  1149 
  1150 * the syntax "if P then x else y" is now available in addition to
  1151 if(P,x,y);
  1152 
  1153 
  1154 *** Internal programming interfaces ***
  1155 
  1156 * tuned simplifier trace output; new flag debug_simp;
  1157 
  1158 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1159 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1160 
  1161 * AxClass.axclass_tac lost the theory argument;
  1162 
  1163 * tuned current_goals_markers semantics: begin / end goal avoids
  1164 printing empty lines;
  1165 
  1166 * removed prs and prs_fn hook, which was broken because it did not
  1167 include \n in its semantics, forcing writeln to add one
  1168 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1169 string -> unit if you really want to output text without newline;
  1170 
  1171 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1172 plain output, interface builders may have to enable 'isabelle_font'
  1173 mode to get Isabelle font glyphs as before;
  1174 
  1175 * refined token_translation interface; INCOMPATIBILITY: output length
  1176 now of type real instead of int;
  1177 
  1178 * theory loader actions may be traced via new ThyInfo.add_hook
  1179 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1180 your own database of information attached to *whole* theories -- as
  1181 opposed to intra-theory data slots offered via TheoryDataFun;
  1182 
  1183 * proper handling of dangling sort hypotheses (at last!);
  1184 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1185 extra sort hypotheses that can be witnessed from the type signature;
  1186 the force_strip_shyps flag is gone, any remaining shyps are simply
  1187 left in the theorem (with a warning issued by strip_shyps_warning);
  1188 
  1189 
  1190 
  1191 New in Isabelle98-1 (October 1998)
  1192 ----------------------------------
  1193 
  1194 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1195 
  1196 * several changes of automated proof tools;
  1197 
  1198 * HOL: major changes to the inductive and datatype packages, including
  1199 some minor incompatibilities of theory syntax;
  1200 
  1201 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1202 called `inj_on';
  1203 
  1204 * HOL: removed duplicate thms in Arith:
  1205   less_imp_add_less  should be replaced by  trans_less_add1
  1206   le_imp_add_le      should be replaced by  trans_le_add1
  1207 
  1208 * HOL: unary minus is now overloaded (new type constraints may be
  1209 required);
  1210 
  1211 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1212 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1213 now taken as an integer constant.
  1214 
  1215 * Pure: ML function 'theory_of' renamed to 'theory';
  1216 
  1217 
  1218 *** Proof tools ***
  1219 
  1220 * Simplifier:
  1221   1. Asm_full_simp_tac is now more aggressive.
  1222      1. It will sometimes reorient premises if that increases their power to
  1223         simplify.
  1224      2. It does no longer proceed strictly from left to right but may also
  1225         rotate premises to achieve further simplification.
  1226      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1227      old Asm_full_simp_tac in that it does not rotate premises.
  1228   2. The simplifier now knows a little bit about nat-arithmetic.
  1229 
  1230 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1231 allows for selected deletion of wrappers, by introduction of names for
  1232 wrapper functionals.  This implies that addbefore, addSbefore,
  1233 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1234 and that adding two tactics with the same name overwrites the first
  1235 one (emitting a warning).
  1236   type wrapper = (int -> tactic) -> (int -> tactic)
  1237   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1238   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1239   delWrapper, delSWrapper: claset *  string            -> claset
  1240   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1241 
  1242 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1243 semantics; addbefore now affects only the unsafe part of step_tac
  1244 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1245 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1246 by Force_tac;
  1247 
  1248 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1249 compWrapper; added safe wrapper (and access functions for it);
  1250 
  1251 * HOL/split_all_tac is now much faster and fails if there is nothing
  1252 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1253 and the names of the automatically generated variables have changed.
  1254 split_all_tac has moved within claset() from unsafe wrappers to safe
  1255 wrappers, which means that !!-bound variables are split much more
  1256 aggressively, and safe_tac and clarify_tac now split such variables.
  1257 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1258 Note: the same holds for record_split_tac, which does the job of
  1259 split_all_tac for record fields.
  1260 
  1261 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1262 permanently to the default simpset using Addsplits just like
  1263 Addsimps. They can be removed via Delsplits just like
  1264 Delsimps. Lower-case versions are also available.
  1265 
  1266 * HOL/Simplifier: The rule split_if is now part of the default
  1267 simpset. This means that the simplifier will eliminate all occurrences
  1268 of if-then-else in the conclusion of a goal. To prevent this, you can
  1269 either remove split_if completely from the default simpset by
  1270 `Delsplits [split_if]' or remove it in a specific call of the
  1271 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1272 other case splitting rules to/from the default simpset: every datatype
  1273 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1274 t is the name of the datatype).
  1275 
  1276 * Classical reasoner / Simplifier combination: new force_tac (and
  1277 derivatives Force_tac, force) combines rewriting and classical
  1278 reasoning (and whatever other tools) similarly to auto_tac, but is
  1279 aimed to solve the given subgoal completely.
  1280 
  1281 
  1282 *** General ***
  1283 
  1284 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1285 and `goalw': the theory is no longer needed as an explicit argument -
  1286 the current theory context is used; assumptions are no longer returned
  1287 at the ML-level unless one of them starts with ==> or !!; it is
  1288 recommended to convert to these new commands using isatool fixgoal
  1289 (backup your sources first!);
  1290 
  1291 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1292 the current theory context, and 'theory' to lookup stored theories;
  1293 
  1294 * new theory section 'locale' for declaring constants, assumptions and
  1295 definitions that have local scope;
  1296 
  1297 * new theory section 'nonterminals' for purely syntactic types;
  1298 
  1299 * new theory section 'setup' for generic ML setup functions
  1300 (e.g. package initialization);
  1301 
  1302 * the distribution now includes Isabelle icons: see
  1303 lib/logo/isabelle-{small,tiny}.xpm;
  1304 
  1305 * isatool install - install binaries with absolute references to
  1306 ISABELLE_HOME/bin;
  1307 
  1308 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1309 
  1310 * print mode 'emacs' reserved for Isamode;
  1311 
  1312 * support multiple print (ast) translations per constant name;
  1313 
  1314 * theorems involving oracles are now printed with a suffixed [!];
  1315 
  1316 
  1317 *** HOL ***
  1318 
  1319 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1320 
  1321 * HOL/inductive package reorganized and improved: now supports mutual
  1322 definitions such as
  1323 
  1324   inductive EVEN ODD
  1325     intrs
  1326       null "0 : EVEN"
  1327       oddI "n : EVEN ==> Suc n : ODD"
  1328       evenI "n : ODD ==> Suc n : EVEN"
  1329 
  1330 new theorem list "elims" contains an elimination rule for each of the
  1331 recursive sets; inductive definitions now handle disjunctive premises
  1332 correctly (also ZF);
  1333 
  1334 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1335 "mutual_induct" no longer exists - the induction rule is always
  1336 contained in "induct";
  1337 
  1338 
  1339 * HOL/datatype package re-implemented and greatly improved: now
  1340 supports mutually recursive datatypes such as
  1341 
  1342   datatype
  1343     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1344             | SUM ('a aexp) ('a aexp)
  1345             | DIFF ('a aexp) ('a aexp)
  1346             | NUM 'a
  1347   and
  1348     'a bexp = LESS ('a aexp) ('a aexp)
  1349             | AND ('a bexp) ('a bexp)
  1350             | OR ('a bexp) ('a bexp)
  1351 
  1352 as well as indirectly recursive datatypes such as
  1353 
  1354   datatype
  1355     ('a, 'b) term = Var 'a
  1356                   | App 'b ((('a, 'b) term) list)
  1357 
  1358 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1359 induction on mutually / indirectly recursive datatypes.
  1360 
  1361 Primrec equations are now stored in theory and can be accessed via
  1362 <function_name>.simps.
  1363 
  1364 INCOMPATIBILITIES:
  1365 
  1366   - Theories using datatypes must now have theory Datatype as an
  1367     ancestor.
  1368   - The specific <typename>.induct_tac no longer exists - use the
  1369     generic induct_tac instead.
  1370   - natE has been renamed to nat.exhaust - use exhaust_tac
  1371     instead of res_inst_tac ... natE. Note that the variable
  1372     names in nat.exhaust differ from the names in natE, this
  1373     may cause some "fragile" proofs to fail.
  1374   - The theorems split_<typename>_case and split_<typename>_case_asm
  1375     have been renamed to <typename>.split and <typename>.split_asm.
  1376   - Since default sorts of type variables are now handled correctly,
  1377     some datatype definitions may have to be annotated with explicit
  1378     sort constraints.
  1379   - Primrec definitions no longer require function name and type
  1380     of recursive argument.
  1381 
  1382 Consider using isatool fixdatatype to adapt your theories and proof
  1383 scripts to the new package (backup your sources first!).
  1384 
  1385 
  1386 * HOL/record package: considerably improved implementation; now
  1387 includes concrete syntax for record types, terms, updates; theorems
  1388 for surjective pairing and splitting !!-bound record variables; proof
  1389 support is as follows:
  1390 
  1391   1) standard conversions (selectors or updates applied to record
  1392 constructor terms) are part of the standard simpset;
  1393 
  1394   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1395 made part of standard simpset and claset via addIffs;
  1396 
  1397   3) a tactic for record field splitting (record_split_tac) is part of
  1398 the standard claset (addSWrapper);
  1399 
  1400 To get a better idea about these rules you may retrieve them via
  1401 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1402 the name of your record type.
  1403 
  1404 The split tactic 3) conceptually simplifies by the following rule:
  1405 
  1406   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1407 
  1408 Thus any record variable that is bound by meta-all will automatically
  1409 blow up into some record constructor term, consequently the
  1410 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1411 solve record problems automatically.
  1412 
  1413 
  1414 * reorganized the main HOL image: HOL/Integ and String loaded by
  1415 default; theory Main includes everything;
  1416 
  1417 * automatic simplification of integer sums and comparisons, using cancellation;
  1418 
  1419 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1420 
  1421 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1422 
  1423 * many new identities for unions, intersections, set difference, etc.;
  1424 
  1425 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1426 called split_if, split_split, split_sum_case and split_nat_case (to go
  1427 with add/delsplits);
  1428 
  1429 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1430 (?x::unit) = (); this is made part of the default simpset, which COULD
  1431 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1432 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1433 unit_abs_eta_conv is added in order to counter the effect of
  1434 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1435 %u.f();
  1436 
  1437 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1438 makes more sense);
  1439 
  1440 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1441   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1442   disjointness reasoning but breaking a few old proofs.
  1443 
  1444 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1445 to 'converse' from 'inverse' (for compatibility with ZF and some
  1446 literature);
  1447 
  1448 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1449 the well-founded relation;
  1450 
  1451 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1452     Compl A.  The "Compl" syntax remains available as input syntax for this
  1453     release ONLY.
  1454 
  1455 * HOL/Update: new theory of function updates:
  1456     f(a:=b) == %x. if x=a then b else f x
  1457 may also be iterated as in f(a:=b,c:=d,...);
  1458 
  1459 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1460 
  1461 * HOL/List:
  1462   - new function list_update written xs[i:=v] that updates the i-th
  1463     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1464   - new function `upt' written [i..j(] which generates the list
  1465     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1466     bound write [i..j], which is a shorthand for [i..j+1(].
  1467   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1468 
  1469 * HOL/Arith:
  1470   - removed 'pred' (predecessor) function;
  1471   - generalized some theorems about n-1;
  1472   - many new laws about "div" and "mod";
  1473   - new laws about greatest common divisors (see theory ex/Primes);
  1474 
  1475 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1476 instead of "inverse";
  1477 
  1478 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1479   of the multiset ordering;
  1480 
  1481 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1482   (not included by default);
  1483 
  1484 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1485 
  1486 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1487   programs, i.e. different program variables may have different types.
  1488 
  1489 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1490   [previously, this check worked only if the rewrite rule was unconditional]
  1491   Now rew can involve either definitions or equalities (either == or =).
  1492 
  1493 
  1494 *** ZF ***
  1495 
  1496 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1497   only the theorems proved on ZF.ML;
  1498 
  1499 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1500   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1501   disjointness reasoning but breaking a few old proofs.
  1502 
  1503 * ZF/Update: new theory of function updates
  1504     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1505   may also be iterated as in f(a:=b,c:=d,...);
  1506 
  1507 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  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 * case_tac provided for compatibility with HOL
  1514     (like the old excluded_middle_tac, but with subgoals swapped)
  1515 
  1516 
  1517 *** Internal programming interfaces ***
  1518 
  1519 * Pure: several new basic modules made available for general use, see
  1520 also src/Pure/README;
  1521 
  1522 * improved the theory data mechanism to support encapsulation (data
  1523 kind name replaced by private Object.kind, acting as authorization
  1524 key); new type-safe user interface via functor TheoryDataFun; generic
  1525 print_data function becomes basically useless;
  1526 
  1527 * removed global_names compatibility flag -- all theory declarations
  1528 are qualified by default;
  1529 
  1530 * module Pure/Syntax now offers quote / antiquote translation
  1531 functions (useful for Hoare logic etc. with implicit dependencies);
  1532 see HOL/ex/Antiquote for an example use;
  1533 
  1534 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1535 cterm -> thm;
  1536 
  1537 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1538 subgoal;
  1539 
  1540 * Display.print_goals function moved to Locale.print_goals;
  1541 
  1542 * standard print function for goals supports current_goals_markers
  1543 variable for marking begin of proof, end of proof, start of goal; the
  1544 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1545 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1546 for example;
  1547 
  1548 
  1549 
  1550 New in Isabelle98 (January 1998)
  1551 --------------------------------
  1552 
  1553 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1554 
  1555 * changed lexical syntax of terms / types: dots made part of long
  1556 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1557 
  1558 * simpset (and claset) reference variable replaced by functions
  1559 simpset / simpset_ref;
  1560 
  1561 * no longer supports theory aliases (via merge) and non-trivial
  1562 implicit merge of thms' signatures;
  1563 
  1564 * most internal names of constants changed due to qualified names;
  1565 
  1566 * changed Pure/Sequence interface (see Pure/seq.ML);
  1567 
  1568 
  1569 *** General Changes ***
  1570 
  1571 * hierachically structured name spaces (for consts, types, axms, thms
  1572 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1573 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1574 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1575 long_names for fully qualified output names; NOTE: ML programs
  1576 (special tactics, packages etc.) referring to internal names may have
  1577 to be adapted to cope with fully qualified names; in case of severe
  1578 backward campatibility problems try setting 'global_names' at compile
  1579 time to have enrything declared within a flat name space; one may also
  1580 fine tune name declarations in theories via the 'global' and 'local'
  1581 section;
  1582 
  1583 * reimplemented the implicit simpset and claset using the new anytype
  1584 data filed in signatures; references simpset:simpset ref etc. are
  1585 replaced by functions simpset:unit->simpset and
  1586 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1587 to patch your ML files accordingly;
  1588 
  1589 * HTML output now includes theory graph data for display with Java
  1590 applet or isatool browser; data generated automatically via isatool
  1591 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1592 
  1593 * defs may now be conditional; improved rewrite_goals_tac to handle
  1594 conditional equations;
  1595 
  1596 * defs now admits additional type arguments, using TYPE('a) syntax;
  1597 
  1598 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1599 creates a new theory node; implicit merge of thms' signatures is
  1600 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1601 transfer:theory->thm->thm in (rare) cases;
  1602 
  1603 * improved handling of draft signatures / theories; draft thms (and
  1604 ctyps, cterms) are automatically promoted to real ones;
  1605 
  1606 * slightly changed interfaces for oracles: admit many per theory, named
  1607 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1608 
  1609 * print_goals: optional output of const types (set show_consts and
  1610 show_types);
  1611 
  1612 * improved output of warnings (###) and errors (***);
  1613 
  1614 * subgoal_tac displays a warning if the new subgoal has type variables;
  1615 
  1616 * removed old README and Makefiles;
  1617 
  1618 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1619 
  1620 * removed obsolete init_pps and init_database;
  1621 
  1622 * deleted the obsolete tactical STATE, which was declared by
  1623     fun STATE tacfun st = tacfun st st;
  1624 
  1625 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1626 (which abbreviates $HOME);
  1627 
  1628 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1629 use isatool fixseq to adapt your ML programs (this works for fully
  1630 qualified references to the Sequence structure only!);
  1631 
  1632 * use_thy no longer requires writable current directory; it always
  1633 reloads .ML *and* .thy file, if either one is out of date;
  1634 
  1635 
  1636 *** Classical Reasoner ***
  1637 
  1638 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1639 tactics that use classical reasoning to simplify a subgoal without
  1640 splitting it into several subgoals;
  1641 
  1642 * Safe_tac: like safe_tac but uses the default claset;
  1643 
  1644 
  1645 *** Simplifier ***
  1646 
  1647 * added simplification meta rules:
  1648     (asm_)(full_)simplify: simpset -> thm -> thm;
  1649 
  1650 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1651 logics (again);
  1652 
  1653 * added prems argument to simplification procedures;
  1654 
  1655 * HOL, FOL, ZF: added infix function `addsplits':
  1656   instead of `<simpset> setloop (split_tac <thms>)'
  1657   you can simply write `<simpset> addsplits <thms>'
  1658 
  1659 
  1660 *** Syntax ***
  1661 
  1662 * TYPE('a) syntax for type reflection terms;
  1663 
  1664 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1665 
  1666 * pretty printer: changed order of mixfix annotation preference (again!);
  1667 
  1668 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1669 
  1670 
  1671 *** HOL ***
  1672 
  1673 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1674   with `addloop' of the simplifier to faciliate case splitting in premises.
  1675 
  1676 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1677 
  1678 * HOL/Auth: new protocol proofs including some for the Internet
  1679   protocol TLS;
  1680 
  1681 * HOL/Map: new theory of `maps' a la VDM;
  1682 
  1683 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1684 cancelling out common nat summands from =, <, <= (in)equalities, or
  1685 differences; simplification procedures nat_cancel_factor for
  1686 cancelling common factor from =, <, <= (in)equalities over natural
  1687 sums; nat_cancel contains both kinds of procedures, it is installed by
  1688 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1689 
  1690 * HOL/simplifier: terms of the form
  1691   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1692   are rewritten to
  1693   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1694   and those of the form
  1695   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1696   are rewritten to
  1697   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1698 
  1699 * HOL/datatype
  1700   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1701 
  1702   P(t_case f1 ... fn x) =
  1703      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1704         ...
  1705        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1706      )
  1707 
  1708   and a theorem `split_t_case_asm' of the form
  1709 
  1710   P(t_case f1 ... fn x) =
  1711     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1712         ...
  1713        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1714      )
  1715   which can be added to a simpset via `addsplits'. The existing theorems
  1716   expand_list_case and expand_option_case have been renamed to
  1717   split_list_case and split_option_case.
  1718 
  1719 * HOL/Arithmetic:
  1720   - `pred n' is automatically converted to `n-1'.
  1721     Users are strongly encouraged not to use `pred' any longer,
  1722     because it will disappear altogether at some point.
  1723   - Users are strongly encouraged to write "0 < n" rather than
  1724     "n ~= 0". Theorems and proof tools have been modified towards this
  1725     `standard'.
  1726 
  1727 * HOL/Lists:
  1728   the function "set_of_list" has been renamed "set" (and its theorems too);
  1729   the function "nth" now takes its arguments in the reverse order and
  1730   has acquired the infix notation "!" as in "xs!n".
  1731 
  1732 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1733 
  1734 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1735   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1736 
  1737 * HOL/record: extensible records with schematic structural subtyping
  1738 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1739 still lacks various theorems and concrete record syntax;
  1740 
  1741 
  1742 *** HOLCF ***
  1743 
  1744 * removed "axioms" and "generated by" sections;
  1745 
  1746 * replaced "ops" section by extended "consts" section, which is capable of
  1747   handling the continuous function space "->" directly;
  1748 
  1749 * domain package:
  1750   . proves theorems immediately and stores them in the theory,
  1751   . creates hierachical name space,
  1752   . now uses normal mixfix annotations (instead of cinfix...),
  1753   . minor changes to some names and values (for consistency),
  1754   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1755   . separator between mutual domain defs: changed "," to "and",
  1756   . improved handling of sort constraints;  now they have to
  1757     appear on the left-hand side of the equations only;
  1758 
  1759 * fixed LAM <x,y,zs>.b syntax;
  1760 
  1761 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1762 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1763 
  1764 
  1765 *** FOL and ZF ***
  1766 
  1767 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1768   with `addloop' of the simplifier to faciliate case splitting in premises.
  1769 
  1770 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1771 in HOL, they strip ALL and --> from proved theorems;
  1772 
  1773 
  1774 
  1775 New in Isabelle94-8 (May 1997)
  1776 ------------------------------
  1777 
  1778 *** General Changes ***
  1779 
  1780 * new utilities to build / run / maintain Isabelle etc. (in parts
  1781 still somewhat experimental); old Makefiles etc. still functional;
  1782 
  1783 * new 'Isabelle System Manual';
  1784 
  1785 * INSTALL text, together with ./configure and ./build scripts;
  1786 
  1787 * reimplemented type inference for greater efficiency, better error
  1788 messages and clean internal interface;
  1789 
  1790 * prlim command for dealing with lots of subgoals (an easier way of
  1791 setting goals_limit);
  1792 
  1793 
  1794 *** Syntax ***
  1795 
  1796 * supports alternative (named) syntax tables (parser and pretty
  1797 printer); internal interface is provided by add_modesyntax(_i);
  1798 
  1799 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1800 be used in conjunction with the Isabelle symbol font; uses the
  1801 "symbols" syntax table;
  1802 
  1803 * added token_translation interface (may translate name tokens in
  1804 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1805 the current print_mode); IMPORTANT: user print translation functions
  1806 are responsible for marking newly introduced bounds
  1807 (Syntax.mark_boundT);
  1808 
  1809 * token translations for modes "xterm" and "xterm_color" that display
  1810 names in bold, underline etc. or colors (which requires a color
  1811 version of xterm);
  1812 
  1813 * infixes may now be declared with names independent of their syntax;
  1814 
  1815 * added typed_print_translation (like print_translation, but may
  1816 access type of constant);
  1817 
  1818 
  1819 *** Classical Reasoner ***
  1820 
  1821 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1822 some limitations.  Blast_tac...
  1823   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1824   + ignores elimination rules that don't have the correct format
  1825         (the conclusion MUST be a formula variable)
  1826   + ignores types, which can make HOL proofs fail
  1827   + rules must not require higher-order unification, e.g. apply_type in ZF
  1828     [message "Function Var's argument not a bound variable" relates to this]
  1829   + its proof strategy is more general but can actually be slower
  1830 
  1831 * substitution with equality assumptions no longer permutes other
  1832 assumptions;
  1833 
  1834 * minor changes in semantics of addafter (now called addaltern); renamed
  1835 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1836 (and access functions for it);
  1837 
  1838 * improved combination of classical reasoner and simplifier:
  1839   + functions for handling clasimpsets
  1840   + improvement of addss: now the simplifier is called _after_ the
  1841     safe steps.
  1842   + safe variant of addss called addSss: uses safe simplifications
  1843     _during_ the safe steps. It is more complete as it allows multiple
  1844     instantiations of unknowns (e.g. with slow_tac).
  1845 
  1846 *** Simplifier ***
  1847 
  1848 * added interface for simplification procedures (functions that
  1849 produce *proven* rewrite rules on the fly, depending on current
  1850 redex);
  1851 
  1852 * ordering on terms as parameter (used for ordered rewriting);
  1853 
  1854 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1855 
  1856 * the solver is now split into a safe and an unsafe part.
  1857 This should be invisible for the normal user, except that the
  1858 functions setsolver and addsolver have been renamed to setSolver and
  1859 addSolver; added safe_asm_full_simp_tac;
  1860 
  1861 
  1862 *** HOL ***
  1863 
  1864 * a generic induction tactic `induct_tac' which works for all datatypes and
  1865 also for type `nat';
  1866 
  1867 * a generic case distinction tactic `exhaust_tac' which works for all
  1868 datatypes and also for type `nat';
  1869 
  1870 * each datatype comes with a function `size';
  1871 
  1872 * patterns in case expressions allow tuple patterns as arguments to
  1873 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1874 
  1875 * primrec now also works with type nat;
  1876 
  1877 * recdef: a new declaration form, allows general recursive functions to be
  1878 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1879 
  1880 * the constant for negation has been renamed from "not" to "Not" to
  1881 harmonize with FOL, ZF, LK, etc.;
  1882 
  1883 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1884 infinite lists;
  1885 
  1886 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1887 
  1888 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1889 problems in commutative rings, using axiomatic type classes for + and *;
  1890 
  1891 * more examples in HOL/MiniML and HOL/Auth;
  1892 
  1893 * more default rewrite rules for quantifiers, union/intersection;
  1894 
  1895 * a new constant `arbitrary == @x.False';
  1896 
  1897 * HOLCF/IOA replaces old HOL/IOA;
  1898 
  1899 * HOLCF changes: derived all rules and arities
  1900   + axiomatic type classes instead of classes
  1901   + typedef instead of faking type definitions
  1902   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1903   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1904   + eliminated the types void, one, tr
  1905   + use unit lift and bool lift (with translations) instead of one and tr
  1906   + eliminated blift from Lift3.thy (use Def instead of blift)
  1907   all eliminated rules are derived as theorems --> no visible changes ;
  1908 
  1909 
  1910 *** ZF ***
  1911 
  1912 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1913 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1914 as ZF_cs addSIs [equalityI];
  1915 
  1916 
  1917 
  1918 New in Isabelle94-7 (November 96)
  1919 ---------------------------------
  1920 
  1921 * allowing negative levels (as offsets) in prlev and choplev;
  1922 
  1923 * super-linear speedup for large simplifications;
  1924 
  1925 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1926 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1927 FAIL); can suppress it using the command Delsimps (ex_simps @
  1928 all_simps); De Morgan laws are also now included, by default;
  1929 
  1930 * improved printing of ==>  :  ~:
  1931 
  1932 * new object-logic "Sequents" adds linear logic, while replacing LK
  1933 and Modal (thanks to Sara Kalvala);
  1934 
  1935 * HOL/Auth: correctness proofs for authentication protocols;
  1936 
  1937 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1938 examples on HOL/Auth);
  1939 
  1940 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1941 the rewriter and classical reasoner simultaneously;
  1942 
  1943 * function uresult no longer returns theorems in "standard" format;
  1944 regain previous version by: val uresult = standard o uresult;
  1945 
  1946 
  1947 
  1948 New in Isabelle94-6
  1949 -------------------
  1950 
  1951 * oracles -- these establish an interface between Isabelle and trusted
  1952 external reasoners, which may deliver results as theorems;
  1953 
  1954 * proof objects (in particular record all uses of oracles);
  1955 
  1956 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1957 
  1958 * "constdefs" section in theory files;
  1959 
  1960 * "primrec" section (HOL) no longer requires names;
  1961 
  1962 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1963 
  1964 
  1965 
  1966 New in Isabelle94-5
  1967 -------------------
  1968 
  1969 * reduced space requirements;
  1970 
  1971 * automatic HTML generation from theories;
  1972 
  1973 * theory files no longer require "..." (quotes) around most types;
  1974 
  1975 * new examples, including two proofs of the Church-Rosser theorem;
  1976 
  1977 * non-curried (1994) version of HOL is no longer distributed;
  1978 
  1979 
  1980 
  1981 New in Isabelle94-4
  1982 -------------------
  1983 
  1984 * greatly reduced space requirements;
  1985 
  1986 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1987 
  1988 * searchable theorem database (see the section "Retrieving theorems" on
  1989 page 8 of the Reference Manual);
  1990 
  1991 * new examples, including Grabczewski's monumental case study of the
  1992 Axiom of Choice;
  1993 
  1994 * The previous version of HOL renamed to Old_HOL;
  1995 
  1996 * The new version of HOL (previously called CHOL) uses a curried syntax
  1997 for functions.  Application looks like f a b instead of f(a,b);
  1998 
  1999 * Mutually recursive inductive definitions finally work in HOL;
  2000 
  2001 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2002 translates to the operator "split";
  2003 
  2004 
  2005 
  2006 New in Isabelle94-3
  2007 -------------------
  2008 
  2009 * new infix operator, addss, allowing the classical reasoner to
  2010 perform simplification at each step of its search.  Example:
  2011         fast_tac (cs addss ss)
  2012 
  2013 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2014 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2015 look like (a,b) instead of <a,b>;
  2016 
  2017 * PLEASE NOTE: CHOL will eventually replace HOL!
  2018 
  2019 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2020 It translates to the operator "split".  A new theory of integers is available;
  2021 
  2022 * In ZF, integer numerals now denote two's-complement binary integers.
  2023 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2024 
  2025 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2026 of the Axiom of Choice;
  2027 
  2028 
  2029 
  2030 New in Isabelle94-2
  2031 -------------------
  2032 
  2033 * Significantly faster resolution;
  2034 
  2035 * the different sections in a .thy file can now be mixed and repeated
  2036 freely;
  2037 
  2038 * Database of theorems for FOL, HOL and ZF.  New
  2039 commands including qed, qed_goal and bind_thm store theorems in the database.
  2040 
  2041 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2042 a given theory (thms_of), or find out what theory a theorem was proved in
  2043 (theory_of_thm);
  2044 
  2045 * Bugs fixed in the inductive definition and datatype packages;
  2046 
  2047 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2048 and HOL_dup_cs obsolete;
  2049 
  2050 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2051 have been removed;
  2052 
  2053 * Simpler definition of function space in ZF;
  2054 
  2055 * new results about cardinal and ordinal arithmetic in ZF;
  2056 
  2057 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2058 types;
  2059 
  2060 
  2061 $Id$