NEWS
author nipkow
Thu Dec 13 16:48:34 2001 +0100 (2001-12-13)
changeset 12489 c92e38c3cbaa
parent 12472 3307149f1ec2
child 12538 150af0a4bb11
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in Isabelle2001 (December 2001)
     5 -----------------------------------
     6 
     7 *** Document preparation ***
     8 
     9 * greatly simplified document preparation setup, including more
    10 graceful interpretation of isatool usedir -i/-d/-D options, and more
    11 instructive isatool mkdir; users should basically be able to get
    12 started with "isatool mkdir Test && isatool make";
    13 
    14 * theory dependency graph may now be incorporated into documents;
    15 isatool usedir -g true will produce session_graph.eps/.pdf for use
    16 with \includegraphics of LaTeX;
    17 
    18 * proper spacing of consecutive markup elements, especially text
    19 blocks after section headings;
    20 
    21 * support bold style (for single symbols only), input syntax is like
    22 this: "\<^bold>\<alpha>" or "\<^bold>A";
    23 
    24 * \<bullet> is now output as bold \cdot by default, which looks much
    25 better in printed text;
    26 
    27 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    28 note that these symbols are currently unavailable in Proof General /
    29 X-Symbol;
    30 
    31 
    32 *** Isar ***
    33 
    34 * Pure/Provers: improved proof by cases and induction;
    35   - 'case' command admits impromptu naming of parameters (such as
    36     "case (Suc n)");
    37   - 'induct' method divinates rule instantiation from the inductive
    38     claim; no longer requires excessive ?P bindings for proper
    39     instantiation of cases;
    40   - 'induct' method properly enumerates all possibilities of set/type
    41     rules; as a consequence facts may be also passed through *type*
    42     rules without further ado;
    43   - 'induct' method now derives symbolic cases from the *rulified*
    44     rule (before it used to rulify cases stemming from the internal
    45     atomized version); this means that the context of a non-atomic
    46     statement becomes is included in the hypothesis, avoiding the
    47     slightly cumbersome show "PROP ?case" form;
    48   - 'induct' may now use elim-style induction rules without chaining
    49     facts, using ``missing'' premises from the goal state; this allows
    50     rules stemming from inductive sets to be applied in unstructured
    51     scripts, while still benefitting from proper handling of non-atomic
    52     statements; NB: major inductive premises need to be put first, all
    53     the rest of the goal is passed through the induction;
    54   - 'induct' proper support for mutual induction involving non-atomic
    55     rule statements (uses the new concept of simultaneous goals, see
    56     below);
    57   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    58   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    59   - moved induct/cases attributes to Pure, methods to Provers;
    60   - generic method setup instantiated for FOL and HOL;
    61 
    62 * Pure: support multiple simultaneous goal statements, for example
    63 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    64 meta-level mechanism, this acts as if several individual goals had
    65 been stated separately; in particular common proof methods need to be
    66 repeated in order to cover all claims; note that a single elimination
    67 step is *not* sufficient to establish the two conjunctions, so this
    68 fails:
    69 
    70   assume "A & B" then have A and B ..   (*".." fails*)
    71 
    72 better use "obtain" in situations as above; alternative refer to
    73 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    74 
    75 * Pure: proper integration with ``locales''; unlike the original
    76 version by Florian Kammüller, Isar locales package high-level proof
    77 contexts rather than raw logical ones (e.g. we admit to include
    78 attributes everywhere); operations on locales include merge and
    79 rename; e.g. see HOL/ex/Locales.thy;
    80 
    81 * Pure: theory goals now support ad-hoc contexts, which are discharged
    82 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    83 coincides with that of a locale body;
    84 
    85 * Pure: renamed "antecedent" case to "rule_context";
    86 
    87 * Pure: added 'corollary' command;
    88 
    89 * Pure: fixed 'token_translation' command;
    90 
    91 * Pure: removed obsolete 'exported' attribute;
    92 
    93 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    94 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    95 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    96 
    97 * Pure: method 'atomize' presents local goal premises as object-level
    98 statements (atomic meta-level propositions); setup controlled via
    99 rewrite rules declarations of 'atomize' attribute; example
   100 application: 'induct' method with proper rule statements in improper
   101 proof *scripts*;
   102 
   103 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   104 now consider the syntactic context of assumptions, giving a better
   105 chance to get type-inference of the arguments right (this is
   106 especially important for locales);
   107 
   108 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   109 mode;
   110 
   111 * Pure/obtain: the formal conclusion "thesis", being marked as
   112 ``internal'', may no longer be reference directly in the text;
   113 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   114 situations;
   115 
   116 * Pure: generic 'sym' attribute which declares a rule both as pure
   117 'elim?' and for the 'symmetric' operation;
   118 
   119 * Pure/Provers/classical: simplified integration with pure rule
   120 attributes and methods; the classical "intro?/elim?/dest?"
   121 declarations coincide with the pure ones; the "rule" method no longer
   122 includes classically swapped intros; "intro" and "elim" methods no
   123 longer pick rules from the context; also got rid of ML declarations
   124 AddXIs/AddXEs/AddXDs; all of this has some potential for
   125 INCOMPATIBILITY;
   126 
   127 * Provers/classical: attribute 'swapped' produces classical inversions
   128 of introduction rules;
   129 
   130 * Provers/simplifier: 'simplified' attribute may refer to explicit
   131 rules instead of full simplifier context; 'iff' attribute handles
   132 conditional rules;
   133 
   134 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   135 
   136 * HOL: 'recdef' now fails on unfinished automated proofs, use
   137 "(permissive)" option to recover old behavior;
   138 
   139 * HOL: 'inductive' no longer features separate (collective) attributes
   140 for 'intros' (was found too confusing);
   141 
   142 * HOL: properly declared induction rules less_induct and
   143 wf_induct_rule;
   144 
   145 * HOLCF: domain package adapted to new-style theories, e.g. see
   146 HOLCF/ex/Dnat.thy;
   147 
   148 * ZF: proper integration of logic-specific tools and packages,
   149 including theory commands '(co)inductive', '(co)datatype',
   150 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   151 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   152 
   153 
   154 *** HOL ***
   155 
   156 * HOL: moved over to sane numeral syntax; the new policy is as
   157 follows:
   158 
   159   - 0 and 1 are polymorphic constants, which are defined on any
   160   numeric type (nat, int, real etc.);
   161 
   162   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   163   binary representation internally;
   164 
   165   - type nat has special constructor Suc, and generally prefers Suc 0
   166   over 1::nat and Suc (Suc 0) over 2::nat;
   167 
   168 This change may cause significant problems of INCOMPATIBILITY; here
   169 are some hints on converting existing sources:
   170 
   171   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   172   entities, so expressions involving "-" (unary or binary minus) need
   173   to be spaced properly;
   174 
   175   - existing occurrences of "1" may need to be constraint "1::nat" or
   176   even replaced by Suc 0; similar for old "2";
   177 
   178   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   179 
   180   - remove all special provisions on numerals in proofs;
   181 
   182 * HOL: the class of all HOL types is now called "type" rather than
   183 "term"; INCOMPATIBILITY, need to adapt references to this type class
   184 in axclass/classes, instance/arities, and (usually rare) occurrences
   185 in typings (of consts etc.); internally the class is called
   186 "HOL.type", ML programs should refer to HOLogic.typeS;
   187 
   188 * HOL/record package improvements:
   189   - new derived operations "fields" to build a partial record section,
   190     "extend" to promote a fixed record to a record scheme, and
   191     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   192     declared as simp by default;
   193   - removed "make_scheme" operations (use "make" with "extend") --
   194     INCOMPATIBILITY;
   195   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   196   - provides cases/induct rules for use with corresponding Isar
   197     methods (for concrete records, record schemes, concrete more
   198     parts, and schematic more parts -- in that order);
   199   - internal definitions directly based on a light-weight abstract
   200     theory of product types over typedef rather than datatype;
   201 
   202 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   203 
   204 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   205 (beware of argument permutation!);
   206 
   207 * HOL: linorder_less_split superseded by linorder_cases;
   208 
   209 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   210 to peripheral theory "Hilbert_Choice";
   211 
   212 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   213 in this (rare) case use:
   214 
   215   delSWrapper "split_all_tac"
   216   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   217 
   218 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   219 MAY FAIL;
   220 
   221 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   222 Isabelle's type classes, ^ on functions and relations has too general
   223 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   224 necessary to attach explicit type constraints;
   225 
   226 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   227 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   228 (eg "compI" -> "rel_compI").
   229 
   230 * HOL: syntax translations now work properly with numerals and records
   231 expressions;
   232 
   233 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   234 of "lam" -- INCOMPATIBILITY;
   235 
   236 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   237 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   238 renamed "Product_Type.unit";
   239 
   240 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   241 Florian Kammüller;
   242 
   243 
   244 *** HOLCF ***
   245 
   246 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
   247 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   248 lift.induct_tac, always use UU instead of Undef;
   249 
   250 
   251 *** ZF ***
   252 
   253 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   254 typeless version of the formalism;
   255 
   256 * ZF/Induct: new directory for examples of inductive definitions,
   257 including theory Multiset for multiset orderings;
   258 
   259 * ZF: the integer library now covers quotients and remainders, with
   260 many laws relating division to addition, multiplication, etc.;
   261 
   262 
   263 *** General ***
   264 
   265 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   266 variable proof controls level of detail: 0 = no proofs (only oracle
   267 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   268 also ref manual for further ML interfaces;
   269 
   270 * Pure/axclass: removed obsolete ML interface
   271 goal_subclass/goal_arity;
   272 
   273 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   274 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   275 separate tokens, so expressions involving minus need to be spaced
   276 properly;
   277 
   278 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   279 rather than "infixl" or "infixr";
   280 
   281 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   282 sort constraint specifications in type inference; e.g. "x::_::foo"
   283 ensures that the type of "x" is of sort "foo" (but not necessarily a
   284 type variable);
   285 
   286 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   287 control output of nested => (types); the default behavior is
   288 "type_brackets";
   289 
   290 * Pure/syntax: builtin parse translation for "_constify" turns valued
   291 tokens into AST constants;
   292 
   293 * Pure/syntax: prefer later declarations of translations and print
   294 translation functions; potential INCOMPATIBILITY: need to reverse
   295 multiple declarations for same syntax element constant;
   296 
   297 * Provers/classical: renamed addaltern to addafter, addSaltern to
   298 addSafter;
   299 
   300 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   301 as well;
   302 
   303 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   304 
   305 * system: Proof General keywords specification is now part of the
   306 Isabelle distribution (see etc/isar-keywords.el);
   307 
   308 * system: smart selection of Isabelle process versus Isabelle
   309 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   310 run both "isabelle" and "Isabelle" even if file names are badly
   311 damaged (executable inspects the case of the first letter of its own
   312 name); added separate "isabelle-process" and "isabelle-interface";
   313 
   314 * system: refrain from any attempt at filtering input streams; no
   315 longer support ``8bit'' encoding of old isabelle font, instead proper
   316 iso-latin characters may now be used; the related isatools
   317 "symbolinput" and "nonascii" have disappeared as well;
   318 
   319 * system: removed old "xterm" interface (the print modes "xterm" and
   320 "xterm_color" are still available for direct use in a suitable
   321 terminal);
   322 
   323 
   324 
   325 New in Isabelle99-2 (February 2001)
   326 -----------------------------------
   327 
   328 *** Overview of INCOMPATIBILITIES ***
   329 
   330 * HOL: please note that theories in the Library and elsewhere often use the
   331 new-style (Isar) format; to refer to their theorems in an ML script you must
   332 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   333 
   334 * HOL: inductive package no longer splits induction rule aggressively,
   335 but only as far as specified by the introductions given; the old
   336 format may be recovered via ML function complete_split_rule or attribute
   337 'split_rule (complete)';
   338 
   339 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   340 gfp_Tarski to gfp_unfold;
   341 
   342 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   343 
   344 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   345 relation); infix "^^" has been renamed "``"; infix "``" has been
   346 renamed "`"; "univalent" has been renamed "single_valued";
   347 
   348 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   349 operation;
   350 
   351 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   352 
   353 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   354 
   355 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   356 consequence, it is no longer monotonic wrt. the local goal context
   357 (which is now passed through the inductive cases);
   358 
   359 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   360 \<gg> to \<ggreater>;
   361 
   362 
   363 *** Document preparation ***
   364 
   365 * \isabellestyle{NAME} selects version of Isabelle output (currently
   366 available: are "it" for near math-mode best-style output, "sl" for
   367 slanted text style, and "tt" for plain type-writer; if no
   368 \isabellestyle command is given, output is according to slanted
   369 type-writer);
   370 
   371 * support sub/super scripts (for single symbols only), input syntax is
   372 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   373 
   374 * some more standard symbols; see Appendix A of the system manual for
   375 the complete list of symbols defined in isabellesym.sty;
   376 
   377 * improved isabelle style files; more abstract symbol implementation
   378 (should now use \isamath{...} and \isatext{...} in custom symbol
   379 definitions);
   380 
   381 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   382 state; Note that presentation of goal states does not conform to
   383 actual human-readable proof documents.  Please do not include goal
   384 states into document output unless you really know what you are doing!
   385 
   386 * proper indentation of antiquoted output with proportional LaTeX
   387 fonts;
   388 
   389 * no_document ML operator temporarily disables LaTeX document
   390 generation;
   391 
   392 * isatool unsymbolize tunes sources for plain ASCII communication;
   393 
   394 
   395 *** Isar ***
   396 
   397 * Pure: Isar now suffers initial goal statements to contain unbound
   398 schematic variables (this does not conform to actual readable proof
   399 documents, due to unpredictable outcome and non-compositional proof
   400 checking); users who know what they are doing may use schematic goals
   401 for Prolog-style synthesis of proven results;
   402 
   403 * Pure: assumption method (an implicit finishing) now handles actual
   404 rules as well;
   405 
   406 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   407 initial goal, declare "that" only as Pure intro (only for single
   408 steps); the "that" rule assumption may now be involved in implicit
   409 finishing, thus ".." becomes a feasible for trivial obtains;
   410 
   411 * Pure: default proof step now includes 'intro_classes'; thus trivial
   412 instance proofs may be performed by "..";
   413 
   414 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   415 statements as well;
   416 
   417 * Pure: more robust selection of calculational rules;
   418 
   419 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   420 rule (as well as the assumption rule);
   421 
   422 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   423 lemmas, using the graph browser tool;
   424 
   425 * Pure: predict failure of "show" in interactive mode;
   426 
   427 * Pure: 'thms_containing' now takes actual terms as arguments;
   428 
   429 * HOL: improved method 'induct' --- now handles non-atomic goals
   430 (potential INCOMPATIBILITY); tuned error handling;
   431 
   432 * HOL: cases and induct rules now provide explicit hints about the
   433 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   434 any remaining facts are inserted into the goal verbatim;
   435 
   436 * HOL: local contexts (aka cases) may now contain term bindings as
   437 well; the 'cases' and 'induct' methods new provide a ?case binding for
   438 the result to be shown in each case;
   439 
   440 * HOL: added 'recdef_tc' command;
   441 
   442 * isatool convert assists in eliminating legacy ML scripts;
   443 
   444 
   445 *** HOL ***
   446 
   447 * HOL/Library: a collection of generic theories to be used together
   448 with main HOL; the theory loader path already includes this directory
   449 by default; the following existing theories have been moved here:
   450 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   451 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   452 
   453 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   454 modelling and verification task performed in Isabelle/HOL +
   455 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   456 
   457 * HOL/Algebra: special summation operator SUM no longer exists, it has
   458 been replaced by setsum; infix 'assoc' now has priority 50 (like
   459 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   460 'domain', this makes the theory consistent with mathematical
   461 literature;
   462 
   463 * HOL basics: added overloaded operations "inverse" and "divide"
   464 (infix "/"), syntax for generic "abs" operation, generic summation
   465 operator \<Sum>;
   466 
   467 * HOL/typedef: simplified package, provide more useful rules (see also
   468 HOL/subset.thy);
   469 
   470 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   471 now expressed as a proper nested rule (old-style tactic scripts may
   472 require atomize_strip_tac to cope with non-atomic premises);
   473 
   474 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   475 to "split_conv" (old name still available for compatibility);
   476 
   477 * HOL: improved concrete syntax for strings (e.g. allows translation
   478 rules with string literals);
   479 
   480 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   481  and Fleuriot's mechanization of analysis, including the transcendental
   482  functions for the reals;
   483 
   484 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   485 
   486 
   487 *** CTT ***
   488 
   489 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   490 "lam" is displayed as TWO lambda-symbols
   491 
   492 * CTT: theory Main now available, containing everything (that is, Bool
   493 and Arith);
   494 
   495 
   496 *** General ***
   497 
   498 * Pure: the Simplifier has been implemented properly as a derived rule
   499 outside of the actual kernel (at last!); the overall performance
   500 penalty in practical applications is about 50%, while reliability of
   501 the Isabelle inference kernel has been greatly improved;
   502 
   503 * print modes "brackets" and "no_brackets" control output of nested =>
   504 (types) and ==> (props); the default behaviour is "brackets";
   505 
   506 * Provers: fast_tac (and friends) now handle actual object-logic rules
   507 as assumptions as well;
   508 
   509 * system: support Poly/ML 4.0;
   510 
   511 * system: isatool install handles KDE version 1 or 2;
   512 
   513 
   514 
   515 New in Isabelle99-1 (October 2000)
   516 ----------------------------------
   517 
   518 *** Overview of INCOMPATIBILITIES ***
   519 
   520 * HOL: simplification of natural numbers is much changed; to partly
   521 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   522 issue the following ML commands:
   523 
   524   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   525   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   526 
   527 * HOL: simplification no longer dives into case-expressions; this is
   528 controlled by "t.weak_case_cong" for each datatype t;
   529 
   530 * HOL: nat_less_induct renamed to less_induct;
   531 
   532 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   533 fixsome to patch .thy and .ML sources automatically;
   534 
   535   select_equality  -> some_equality
   536   select_eq_Ex     -> some_eq_ex
   537   selectI2EX       -> someI2_ex
   538   selectI2         -> someI2
   539   selectI          -> someI
   540   select1_equality -> some1_equality
   541   Eps_sym_eq       -> some_sym_eq_trivial
   542   Eps_eq           -> some_eq_trivial
   543 
   544 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   545 
   546 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   547 instead);
   548 
   549 * HOL: the recursion equations generated by 'recdef' are now called
   550 f.simps instead of f.rules;
   551 
   552 * HOL: qed_spec_mp now also handles bounded ALL as well;
   553 
   554 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   555 sometimes be needed;
   556 
   557 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   558 
   559 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   560 
   561 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   562 product is now "<*>" instead of "Times"; the lexicographic product is
   563 now "<*lex*>" instead of "**";
   564 
   565 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   566 of main HOL, but was unused); better use HOL's datatype package;
   567 
   568 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   569 the old syntax may be recovered as follows:
   570 
   571   syntax (symbols)
   572     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   573       (infixl "\\<oplus>" 100)
   574 
   575 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   576 
   577 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   578 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   579 internally;
   580 
   581 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   582 changed from A/r to A//r;
   583 
   584 * ZF: new treatment of arithmetic (nat & int) may break some old
   585 proofs;
   586 
   587 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   588 rulify -> rule_format, elimify -> elim_format, ...);
   589 
   590 * Isar/Provers: intro/elim/dest attributes changed; renamed
   591 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   592 should have to change intro!! to intro? only); replaced "delrule" by
   593 "rule del";
   594 
   595 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   596 
   597 * Provers: strengthened force_tac by using new first_best_tac;
   598 
   599 * LaTeX document preparation: several changes of isabelle.sty (see
   600 lib/texinputs);
   601 
   602 
   603 *** Document preparation ***
   604 
   605 * formal comments (text blocks etc.) in new-style theories may now
   606 contain antiquotations of thm/prop/term/typ/text to be presented
   607 according to latex print mode; concrete syntax is like this:
   608 @{term[show_types] "f(x) = a + x"};
   609 
   610 * isatool mkdir provides easy setup of Isabelle session directories,
   611 including proper document sources;
   612 
   613 * generated LaTeX sources are now deleted after successful run
   614 (isatool document -c); may retain a copy somewhere else via -D option
   615 of isatool usedir;
   616 
   617 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   618 style files, achieving self-contained LaTeX sources and simplifying
   619 LaTeX debugging;
   620 
   621 * old-style theories now produce (crude) LaTeX output as well;
   622 
   623 * browser info session directories are now self-contained (may be put
   624 on WWW server seperately); improved graphs of nested sessions; removed
   625 graph for 'all sessions';
   626 
   627 * several improvements in isabelle style files; \isabellestyle{it}
   628 produces fake math mode output; \isamarkupheader is now \section by
   629 default; see lib/texinputs/isabelle.sty etc.;
   630 
   631 
   632 *** Isar ***
   633 
   634 * Isar/Pure: local results and corresponding term bindings are now
   635 subject to Hindley-Milner polymorphism (similar to ML); this
   636 accommodates incremental type-inference very nicely;
   637 
   638 * Isar/Pure: new derived language element 'obtain' supports
   639 generalized existence reasoning;
   640 
   641 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   642 support accumulation of results, without applying any rules yet;
   643 useful to collect intermediate results without explicit name
   644 references, and for use with transitivity rules with more than 2
   645 premises;
   646 
   647 * Isar/Pure: scalable support for case-analysis type proofs: new
   648 'case' language element refers to local contexts symbolically, as
   649 produced by certain proof methods; internally, case names are attached
   650 to theorems as "tags";
   651 
   652 * Isar/Pure: theory command 'hide' removes declarations from
   653 class/type/const name spaces;
   654 
   655 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   656 indicate potential overloading;
   657 
   658 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   659 
   660 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   661 "{a,b,c}" instead of {a,b,c};
   662 
   663 * Isar/Pure now provides its own version of intro/elim/dest
   664 attributes; useful for building new logics, but beware of confusion
   665 with the version in Provers/classical;
   666 
   667 * Isar/Pure: the local context of (non-atomic) goals is provided via
   668 case name 'antecedent';
   669 
   670 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   671 to the current context is now done automatically);
   672 
   673 * Isar/Pure: theory command 'method_setup' provides a simple interface
   674 for definining proof methods in ML;
   675 
   676 * Isar/Provers: intro/elim/dest attributes changed; renamed
   677 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   678 most cases, one should have to change intro!! to intro? only);
   679 replaced "delrule" by "rule del";
   680 
   681 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   682 'symmetric' attribute (the latter supercedes [RS sym]);
   683 
   684 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   685 method modifier); 'simp' method: 'only:' modifier removes loopers as
   686 well (including splits);
   687 
   688 * Isar/Provers: Simplifier and Classical methods now support all kind
   689 of modifiers used in the past, including 'cong', 'iff', etc.
   690 
   691 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   692 of Simplifier and Classical reasoner);
   693 
   694 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   695 now support named cases; major packages (inductive, datatype, primrec,
   696 recdef) support case names and properly name parameters;
   697 
   698 * Isar/HOL: new transitivity rules for substitution in inequalities --
   699 monotonicity conditions are extracted to be proven at end of
   700 calculations;
   701 
   702 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   703 method anyway;
   704 
   705 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   706 split_if split_if_asm; datatype package provides theorems foo.splits =
   707 foo.split foo.split_asm for each datatype;
   708 
   709 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   710 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   711 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   712 use "(cases (simplified))" method in proper proof texts);
   713 
   714 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   715 
   716 * Isar: names of theorems etc. may be natural numbers as well;
   717 
   718 * Isar: 'pr' command: optional arguments for goals_limit and
   719 ProofContext.prems_limit; no longer prints theory contexts, but only
   720 proof states;
   721 
   722 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   723 additional print modes to be specified; e.g. "pr(latex)" will print
   724 proof state according to the Isabelle LaTeX style;
   725 
   726 * Isar: improved support for emulating tactic scripts, including proof
   727 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   728 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   729 (for HOL datatypes);
   730 
   731 * Isar: simplified (more robust) goal selection of proof methods: 1st
   732 goal, all goals, or explicit goal specifier (tactic emulation); thus
   733 'proof method scripts' have to be in depth-first order;
   734 
   735 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   736 
   737 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   738 should instead use individual commands for printing items
   739 (print_commands, print_methods etc.);
   740 
   741 * Isar: added 'nothing' --- the empty list of theorems;
   742 
   743 
   744 *** HOL ***
   745 
   746 * HOL/MicroJava: formalization of a fragment of Java, together with a
   747 corresponding virtual machine and a specification of its bytecode
   748 verifier and a lightweight bytecode verifier, including proofs of
   749 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   750 Cornelia Pusch (see also the homepage of project Bali at
   751 http://isabelle.in.tum.de/Bali/);
   752 
   753 * HOL/Algebra: new theory of rings and univariate polynomials, by
   754 Clemens Ballarin;
   755 
   756 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   757 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   758 Rasmussen;
   759 
   760 * HOL/Lattice: fundamental concepts of lattice theory and order
   761 structures, including duals, properties of bounds versus algebraic
   762 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   763 Theorem for complete lattices etc.; may also serve as a demonstration
   764 for abstract algebraic reasoning using axiomatic type classes, and
   765 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   766 
   767 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   768 von Oheimb;
   769 
   770 * HOL/IMPP: extension of IMP with local variables and mutually
   771 recursive procedures, by David von Oheimb;
   772 
   773 * HOL/Lambda: converted into new-style theory and document;
   774 
   775 * HOL/ex/Multiquote: example of multiple nested quotations and
   776 anti-quotations -- basically a generalized version of de-Bruijn
   777 representation; very useful in avoiding lifting of operations;
   778 
   779 * HOL/record: added general record equality rule to simpset; fixed
   780 select-update simplification procedure to handle extended records as
   781 well; admit "r" as field name;
   782 
   783 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   784 other numeric types and also as the identity of groups, rings, etc.;
   785 
   786 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   787 Types nat and int belong to this axclass;
   788 
   789 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   790    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   791    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   792   two terms #m*u and #n*u are replaced by #(m+n)*u
   793     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   794   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   795     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   796 
   797 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   798 powerful prover for predicate logic but knows nothing of clasets; see
   799 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   800 
   801 * HOL: new version of "case_tac" subsumes both boolean case split and
   802 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   803 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   804 
   805 * HOL: simplification no longer dives into case-expressions: only the
   806 selector expression is simplified, but not the remaining arms; to
   807 enable full simplification of case-expressions for datatype t, you may
   808 remove t.weak_case_cong from the simpset, either globally (Delcongs
   809 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   810 
   811 * HOL/recdef: the recursion equations generated by 'recdef' for
   812 function 'f' are now called f.simps instead of f.rules; if all
   813 termination conditions are proved automatically, these simplification
   814 rules are added to the simpset, as in primrec; rules may be named
   815 individually as well, resulting in a separate list of theorems for
   816 each equation;
   817 
   818 * HOL/While is a new theory that provides a while-combinator. It
   819 permits the definition of tail-recursive functions without the
   820 provision of a termination measure. The latter is necessary once the
   821 invariant proof rule for while is applied.
   822 
   823 * HOL: new (overloaded) notation for the set of elements below/above
   824 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   825 
   826 * HOL: theorems impI, allI, ballI bound as "strip";
   827 
   828 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   829 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   830 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   831 
   832 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   833 
   834 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   835 main HOL, but was unused);
   836 
   837 * HOL: fewer consts declared as global (e.g. have to refer to
   838 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   839 
   840 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   841 in case of overlap with user translations (e.g. judgements over
   842 tuples); (note that the underlying logical represenation is still
   843 bogus);
   844 
   845 
   846 *** ZF ***
   847 
   848 * ZF: simplification automatically cancels common terms in arithmetic
   849 expressions over nat and int;
   850 
   851 * ZF: new treatment of nat to minimize type-checking: all operators
   852 coerce their operands to a natural number using the function natify,
   853 making the algebraic laws unconditional;
   854 
   855 * ZF: as above, for int: operators coerce their operands to an integer
   856 using the function intify;
   857 
   858 * ZF: the integer library now contains many of the usual laws for the
   859 orderings, including $<=, and monotonicity laws for $+ and $*;
   860 
   861 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   862 simplification;
   863 
   864 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   865 to the simplifier and classical reasoner simultaneously;
   866 
   867 
   868 *** General ***
   869 
   870 * Provers: blast_tac now handles actual object-logic rules as
   871 assumptions; note that auto_tac uses blast_tac internally as well;
   872 
   873 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   874 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   875 
   876 * Provers: delrules now handles destruct rules as well (no longer need
   877 explicit make_elim);
   878 
   879 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   880   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   881 use instead the strong form,
   882   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   883 in HOL, FOL and ZF the function cla_make_elim will create such rules
   884 from destruct-rules;
   885 
   886 * Provers: Simplifier.easy_setup provides a fast path to basic
   887 Simplifier setup for new object-logics;
   888 
   889 * Pure: AST translation rules no longer require constant head on LHS;
   890 
   891 * Pure: improved name spaces: ambiguous output is qualified; support
   892 for hiding of names;
   893 
   894 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   895 XSYMBOL_HOME; no longer need to do manual configuration in most
   896 situations;
   897 
   898 * system: compression of ML heaps images may now be controlled via -c
   899 option of isabelle and isatool usedir (currently only observed by
   900 Poly/ML);
   901 
   902 * system: isatool installfonts may handle X-Symbol fonts as well (very
   903 useful for remote X11);
   904 
   905 * system: provide TAGS file for Isabelle sources;
   906 
   907 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   908 order;
   909 
   910 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   911 timing flag supersedes proof_timing and Toplevel.trace;
   912 
   913 * ML: new combinators |>> and |>>> for incremental transformations
   914 with secondary results (e.g. certain theory extensions):
   915 
   916 * ML: PureThy.add_defs gets additional argument to indicate potential
   917 overloading (usually false);
   918 
   919 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   920 results;
   921 
   922 
   923 
   924 New in Isabelle99 (October 1999)
   925 --------------------------------
   926 
   927 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   928 
   929 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   930 are no longer simplified.  (This allows the simplifier to unfold recursive
   931 functional programs.)  To restore the old behaviour, declare
   932 
   933     Delcongs [if_weak_cong];
   934 
   935 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   936 complement;
   937 
   938 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   939 
   940 * HOL/datatype: mutual_induct_tac no longer exists --
   941   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   942 
   943 * HOL/typedef: fixed type inference for representing set; type
   944 arguments now have to occur explicitly on the rhs as type constraints;
   945 
   946 * ZF: The con_defs part of an inductive definition may no longer refer
   947 to constants declared in the same theory;
   948 
   949 * HOL, ZF: the function mk_cases, generated by the inductive
   950 definition package, has lost an argument.  To simplify its result, it
   951 uses the default simpset instead of a supplied list of theorems.
   952 
   953 * HOL/List: the constructors of type list are now Nil and Cons;
   954 
   955 * Simplifier: the type of the infix ML functions
   956         setSSolver addSSolver setSolver addSolver
   957 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   958 for packaging solvers. A solver is created via
   959         mk_solver: string -> (thm list -> int -> tactic) -> solver
   960 where the string argument is only a comment.
   961 
   962 
   963 *** Proof tools ***
   964 
   965 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   966 decision procedure for linear arithmetic. Currently it is used for
   967 types `nat', `int', and `real' in HOL (see below); it can, should and
   968 will be instantiated for other types and logics as well.
   969 
   970 * The simplifier now accepts rewrite rules with flexible heads, eg
   971      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   972   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   973   matching.
   974 
   975 
   976 *** General ***
   977 
   978 * New Isabelle/Isar subsystem provides an alternative to traditional
   979 tactical theorem proving; together with the ProofGeneral/isar user
   980 interface it offers an interactive environment for developing human
   981 readable proof documents (Isar == Intelligible semi-automated
   982 reasoning); for further information see isatool doc isar-ref,
   983 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   984 
   985 * improved and simplified presentation of theories: better HTML markup
   986 (including colors), graph views in several sizes; isatool usedir now
   987 provides a proper interface for user theories (via -P option); actual
   988 document preparation based on (PDF)LaTeX is available as well (for
   989 new-style theories only); see isatool doc system for more information;
   990 
   991 * native support for Proof General, both for classic Isabelle and
   992 Isabelle/Isar;
   993 
   994 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   995 using the graph browser tool;
   996 
   997 * Isabelle manuals now also available as PDF;
   998 
   999 * theory loader rewritten from scratch (may not be fully
  1000 bug-compatible); old loadpath variable has been replaced by show_path,
  1001 add_path, del_path, reset_path functions; new operations such as
  1002 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1003 isatool doc ref);
  1004 
  1005 * improved isatool install: option -k creates KDE application icon,
  1006 option -p DIR installs standalone binaries;
  1007 
  1008 * added ML_PLATFORM setting (useful for cross-platform installations);
  1009 more robust handling of platform specific ML images for SML/NJ;
  1010 
  1011 * the settings environment is now statically scoped, i.e. it is never
  1012 created again in sub-processes invoked from isabelle, isatool, or
  1013 Isabelle;
  1014 
  1015 * path element specification '~~' refers to '$ISABELLE_HOME';
  1016 
  1017 * in locales, the "assumes" and "defines" parts may be omitted if
  1018 empty;
  1019 
  1020 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1021 long arrows);
  1022 
  1023 * new print_mode "HTML";
  1024 
  1025 * new flag show_tags controls display of tags of theorems (which are
  1026 basically just comments that may be attached by some tools);
  1027 
  1028 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1029 mode and goal output format:
  1030 
  1031 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1032 244c244
  1033 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1034 ---
  1035 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1036 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1037 181c181
  1038 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1039 ---
  1040 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1041 
  1042 * function bind_thms stores lists of theorems (cf. bind_thm);
  1043 
  1044 * new shorthand tactics ftac, eatac, datac, fatac;
  1045 
  1046 * qed (and friends) now accept "" as result name; in that case the
  1047 theorem is not stored, but proper checks and presentation of the
  1048 result still apply;
  1049 
  1050 * theorem database now also indexes constants "Trueprop", "all",
  1051 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1052 
  1053 
  1054 *** HOL ***
  1055 
  1056 ** HOL arithmetic **
  1057 
  1058 * There are now decision procedures for linear arithmetic over nat and
  1059 int:
  1060 
  1061 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1062 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1063 are treated as atomic; subformulae not involving type `nat' or `int'
  1064 are ignored; quantified subformulae are ignored unless they are
  1065 positive universal or negative existential. The tactic has to be
  1066 invoked by hand and can be a little bit slow. In particular, the
  1067 running time is exponential in the number of occurrences of `min' and
  1068 `max', and `-' on `nat'.
  1069 
  1070 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1071 (negated) (in)equalities among the premises and the conclusion into
  1072 account (i.e. no compound formulae) and does not know about `min' and
  1073 `max', and `-' on `nat'. It is fast and is used automatically by the
  1074 simplifier.
  1075 
  1076 NB: At the moment, these decision procedures do not cope with mixed
  1077 nat/int formulae where the two parts interact, such as `m < n ==>
  1078 int(m) < int(n)'.
  1079 
  1080 * HOL/Numeral provides a generic theory of numerals (encoded
  1081 efficiently as bit strings); setup for types nat/int/real is in place;
  1082 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1083 int, existing theories and proof scripts may require a few additional
  1084 type constraints;
  1085 
  1086 * integer division and remainder can now be performed on constant
  1087 arguments;
  1088 
  1089 * many properties of integer multiplication, division and remainder
  1090 are now available;
  1091 
  1092 * An interface to the Stanford Validity Checker (SVC) is available through the
  1093 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1094 are proved automatically.  SVC must be installed separately, and its results
  1095 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1096 invocation of the underlying oracle).  For SVC see
  1097   http://verify.stanford.edu/SVC
  1098 
  1099 * IsaMakefile: the HOL-Real target now builds an actual image;
  1100 
  1101 
  1102 ** HOL misc **
  1103 
  1104 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1105 (in Isabelle/Isar) -- by Gertrud Bauer;
  1106 
  1107 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1108 analysis for assembly languages with subtypes;
  1109 
  1110 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1111 -- avoids syntactic ambiguities and treats state, transition, and
  1112 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1113 changed syntax and (many) tactics;
  1114 
  1115 * HOL/inductive: Now also handles more general introduction rules such
  1116   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1117   theorems are now maintained within the theory (maintained via the
  1118   "mono" attribute);
  1119 
  1120 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1121   (using function types) such as
  1122 
  1123   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1124 
  1125 * HOL/record: record_simproc (part of the default simpset) takes care
  1126 of selectors applied to updated records; record_split_tac is no longer
  1127 part of the default claset; update_defs may now be removed from the
  1128 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1129 
  1130   claset_ref () := claset() addSWrapper record_split_wrapper;
  1131   Delsimprocs [record_simproc]
  1132 
  1133 * HOL/typedef: fixed type inference for representing set; type
  1134 arguments now have to occur explicitly on the rhs as type constraints;
  1135 
  1136 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1137 names rather than an ML expression;
  1138 
  1139 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1140 supplied later.  Program schemes can be defined, such as
  1141     "While B C s = (if B s then While B C (C s) else s)"
  1142 where the well-founded relation can be chosen after B and C have been given.
  1143 
  1144 * HOL/List: the constructors of type list are now Nil and Cons;
  1145 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1146 course, ML tools referring to List.list.op # etc. have to be adapted;
  1147 
  1148 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1149 disabled by default; run isabelle with option -m HOL to get back to
  1150 the original Gordon/HOL-style output;
  1151 
  1152 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1153 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1154 
  1155 * HOL basic syntax simplified (more orthogonal): all variants of
  1156 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1157 Eps operator is provided as well: "SOME x. P[x]";
  1158 
  1159 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1160 
  1161 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1162 thus available for user theories;
  1163 
  1164 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1165 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1166 time;
  1167 
  1168 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1169 several times and then mp;
  1170 
  1171 
  1172 *** LK ***
  1173 
  1174 * the notation <<...>> is now available as a notation for sequences of
  1175 formulas;
  1176 
  1177 * the simplifier is now installed
  1178 
  1179 * the axiom system has been generalized (thanks to Soren Heilmann)
  1180 
  1181 * the classical reasoner now has a default rule database
  1182 
  1183 
  1184 *** ZF ***
  1185 
  1186 * new primrec section allows primitive recursive functions to be given
  1187 directly (as in HOL) over datatypes and the natural numbers;
  1188 
  1189 * new tactics induct_tac and exhaust_tac for induction (or case
  1190 analysis) over datatypes and the natural numbers;
  1191 
  1192 * the datatype declaration of type T now defines the recursor T_rec;
  1193 
  1194 * simplification automatically does freeness reasoning for datatype
  1195 constructors;
  1196 
  1197 * automatic type-inference, with AddTCs command to insert new
  1198 type-checking rules;
  1199 
  1200 * datatype introduction rules are now added as Safe Introduction rules
  1201 to the claset;
  1202 
  1203 * the syntax "if P then x else y" is now available in addition to
  1204 if(P,x,y);
  1205 
  1206 
  1207 *** Internal programming interfaces ***
  1208 
  1209 * tuned simplifier trace output; new flag debug_simp;
  1210 
  1211 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1212 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1213 
  1214 * AxClass.axclass_tac lost the theory argument;
  1215 
  1216 * tuned current_goals_markers semantics: begin / end goal avoids
  1217 printing empty lines;
  1218 
  1219 * removed prs and prs_fn hook, which was broken because it did not
  1220 include \n in its semantics, forcing writeln to add one
  1221 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1222 string -> unit if you really want to output text without newline;
  1223 
  1224 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1225 plain output, interface builders may have to enable 'isabelle_font'
  1226 mode to get Isabelle font glyphs as before;
  1227 
  1228 * refined token_translation interface; INCOMPATIBILITY: output length
  1229 now of type real instead of int;
  1230 
  1231 * theory loader actions may be traced via new ThyInfo.add_hook
  1232 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1233 your own database of information attached to *whole* theories -- as
  1234 opposed to intra-theory data slots offered via TheoryDataFun;
  1235 
  1236 * proper handling of dangling sort hypotheses (at last!);
  1237 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1238 extra sort hypotheses that can be witnessed from the type signature;
  1239 the force_strip_shyps flag is gone, any remaining shyps are simply
  1240 left in the theorem (with a warning issued by strip_shyps_warning);
  1241 
  1242 
  1243 
  1244 New in Isabelle98-1 (October 1998)
  1245 ----------------------------------
  1246 
  1247 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1248 
  1249 * several changes of automated proof tools;
  1250 
  1251 * HOL: major changes to the inductive and datatype packages, including
  1252 some minor incompatibilities of theory syntax;
  1253 
  1254 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1255 called `inj_on';
  1256 
  1257 * HOL: removed duplicate thms in Arith:
  1258   less_imp_add_less  should be replaced by  trans_less_add1
  1259   le_imp_add_le      should be replaced by  trans_le_add1
  1260 
  1261 * HOL: unary minus is now overloaded (new type constraints may be
  1262 required);
  1263 
  1264 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1265 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1266 now taken as an integer constant.
  1267 
  1268 * Pure: ML function 'theory_of' renamed to 'theory';
  1269 
  1270 
  1271 *** Proof tools ***
  1272 
  1273 * Simplifier:
  1274   1. Asm_full_simp_tac is now more aggressive.
  1275      1. It will sometimes reorient premises if that increases their power to
  1276         simplify.
  1277      2. It does no longer proceed strictly from left to right but may also
  1278         rotate premises to achieve further simplification.
  1279      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1280      old Asm_full_simp_tac in that it does not rotate premises.
  1281   2. The simplifier now knows a little bit about nat-arithmetic.
  1282 
  1283 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1284 allows for selected deletion of wrappers, by introduction of names for
  1285 wrapper functionals.  This implies that addbefore, addSbefore,
  1286 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1287 and that adding two tactics with the same name overwrites the first
  1288 one (emitting a warning).
  1289   type wrapper = (int -> tactic) -> (int -> tactic)
  1290   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1291   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1292   delWrapper, delSWrapper: claset *  string            -> claset
  1293   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1294 
  1295 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1296 semantics; addbefore now affects only the unsafe part of step_tac
  1297 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1298 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1299 by Force_tac;
  1300 
  1301 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1302 compWrapper; added safe wrapper (and access functions for it);
  1303 
  1304 * HOL/split_all_tac is now much faster and fails if there is nothing
  1305 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1306 and the names of the automatically generated variables have changed.
  1307 split_all_tac has moved within claset() from unsafe wrappers to safe
  1308 wrappers, which means that !!-bound variables are split much more
  1309 aggressively, and safe_tac and clarify_tac now split such variables.
  1310 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1311 Note: the same holds for record_split_tac, which does the job of
  1312 split_all_tac for record fields.
  1313 
  1314 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1315 permanently to the default simpset using Addsplits just like
  1316 Addsimps. They can be removed via Delsplits just like
  1317 Delsimps. Lower-case versions are also available.
  1318 
  1319 * HOL/Simplifier: The rule split_if is now part of the default
  1320 simpset. This means that the simplifier will eliminate all occurrences
  1321 of if-then-else in the conclusion of a goal. To prevent this, you can
  1322 either remove split_if completely from the default simpset by
  1323 `Delsplits [split_if]' or remove it in a specific call of the
  1324 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1325 other case splitting rules to/from the default simpset: every datatype
  1326 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1327 t is the name of the datatype).
  1328 
  1329 * Classical reasoner / Simplifier combination: new force_tac (and
  1330 derivatives Force_tac, force) combines rewriting and classical
  1331 reasoning (and whatever other tools) similarly to auto_tac, but is
  1332 aimed to solve the given subgoal completely.
  1333 
  1334 
  1335 *** General ***
  1336 
  1337 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1338 and `goalw': the theory is no longer needed as an explicit argument -
  1339 the current theory context is used; assumptions are no longer returned
  1340 at the ML-level unless one of them starts with ==> or !!; it is
  1341 recommended to convert to these new commands using isatool fixgoal
  1342 (backup your sources first!);
  1343 
  1344 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1345 the current theory context, and 'theory' to lookup stored theories;
  1346 
  1347 * new theory section 'locale' for declaring constants, assumptions and
  1348 definitions that have local scope;
  1349 
  1350 * new theory section 'nonterminals' for purely syntactic types;
  1351 
  1352 * new theory section 'setup' for generic ML setup functions
  1353 (e.g. package initialization);
  1354 
  1355 * the distribution now includes Isabelle icons: see
  1356 lib/logo/isabelle-{small,tiny}.xpm;
  1357 
  1358 * isatool install - install binaries with absolute references to
  1359 ISABELLE_HOME/bin;
  1360 
  1361 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1362 
  1363 * print mode 'emacs' reserved for Isamode;
  1364 
  1365 * support multiple print (ast) translations per constant name;
  1366 
  1367 * theorems involving oracles are now printed with a suffixed [!];
  1368 
  1369 
  1370 *** HOL ***
  1371 
  1372 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1373 
  1374 * HOL/inductive package reorganized and improved: now supports mutual
  1375 definitions such as
  1376 
  1377   inductive EVEN ODD
  1378     intrs
  1379       null "0 : EVEN"
  1380       oddI "n : EVEN ==> Suc n : ODD"
  1381       evenI "n : ODD ==> Suc n : EVEN"
  1382 
  1383 new theorem list "elims" contains an elimination rule for each of the
  1384 recursive sets; inductive definitions now handle disjunctive premises
  1385 correctly (also ZF);
  1386 
  1387 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1388 "mutual_induct" no longer exists - the induction rule is always
  1389 contained in "induct";
  1390 
  1391 
  1392 * HOL/datatype package re-implemented and greatly improved: now
  1393 supports mutually recursive datatypes such as
  1394 
  1395   datatype
  1396     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1397             | SUM ('a aexp) ('a aexp)
  1398             | DIFF ('a aexp) ('a aexp)
  1399             | NUM 'a
  1400   and
  1401     'a bexp = LESS ('a aexp) ('a aexp)
  1402             | AND ('a bexp) ('a bexp)
  1403             | OR ('a bexp) ('a bexp)
  1404 
  1405 as well as indirectly recursive datatypes such as
  1406 
  1407   datatype
  1408     ('a, 'b) term = Var 'a
  1409                   | App 'b ((('a, 'b) term) list)
  1410 
  1411 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1412 induction on mutually / indirectly recursive datatypes.
  1413 
  1414 Primrec equations are now stored in theory and can be accessed via
  1415 <function_name>.simps.
  1416 
  1417 INCOMPATIBILITIES:
  1418 
  1419   - Theories using datatypes must now have theory Datatype as an
  1420     ancestor.
  1421   - The specific <typename>.induct_tac no longer exists - use the
  1422     generic induct_tac instead.
  1423   - natE has been renamed to nat.exhaust - use exhaust_tac
  1424     instead of res_inst_tac ... natE. Note that the variable
  1425     names in nat.exhaust differ from the names in natE, this
  1426     may cause some "fragile" proofs to fail.
  1427   - The theorems split_<typename>_case and split_<typename>_case_asm
  1428     have been renamed to <typename>.split and <typename>.split_asm.
  1429   - Since default sorts of type variables are now handled correctly,
  1430     some datatype definitions may have to be annotated with explicit
  1431     sort constraints.
  1432   - Primrec definitions no longer require function name and type
  1433     of recursive argument.
  1434 
  1435 Consider using isatool fixdatatype to adapt your theories and proof
  1436 scripts to the new package (backup your sources first!).
  1437 
  1438 
  1439 * HOL/record package: considerably improved implementation; now
  1440 includes concrete syntax for record types, terms, updates; theorems
  1441 for surjective pairing and splitting !!-bound record variables; proof
  1442 support is as follows:
  1443 
  1444   1) standard conversions (selectors or updates applied to record
  1445 constructor terms) are part of the standard simpset;
  1446 
  1447   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1448 made part of standard simpset and claset via addIffs;
  1449 
  1450   3) a tactic for record field splitting (record_split_tac) is part of
  1451 the standard claset (addSWrapper);
  1452 
  1453 To get a better idea about these rules you may retrieve them via
  1454 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1455 the name of your record type.
  1456 
  1457 The split tactic 3) conceptually simplifies by the following rule:
  1458 
  1459   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1460 
  1461 Thus any record variable that is bound by meta-all will automatically
  1462 blow up into some record constructor term, consequently the
  1463 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1464 solve record problems automatically.
  1465 
  1466 
  1467 * reorganized the main HOL image: HOL/Integ and String loaded by
  1468 default; theory Main includes everything;
  1469 
  1470 * automatic simplification of integer sums and comparisons, using cancellation;
  1471 
  1472 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1473 
  1474 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1475 
  1476 * many new identities for unions, intersections, set difference, etc.;
  1477 
  1478 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1479 called split_if, split_split, split_sum_case and split_nat_case (to go
  1480 with add/delsplits);
  1481 
  1482 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1483 (?x::unit) = (); this is made part of the default simpset, which COULD
  1484 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1485 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1486 unit_abs_eta_conv is added in order to counter the effect of
  1487 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1488 %u.f();
  1489 
  1490 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1491 makes more sense);
  1492 
  1493 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1494   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1495   disjointness reasoning but breaking a few old proofs.
  1496 
  1497 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1498 to 'converse' from 'inverse' (for compatibility with ZF and some
  1499 literature);
  1500 
  1501 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1502 the well-founded relation;
  1503 
  1504 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1505     Compl A.  The "Compl" syntax remains available as input syntax for this
  1506     release ONLY.
  1507 
  1508 * HOL/Update: new theory of function updates:
  1509     f(a:=b) == %x. if x=a then b else f x
  1510 may also be iterated as in f(a:=b,c:=d,...);
  1511 
  1512 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1513 
  1514 * HOL/List:
  1515   - new function list_update written xs[i:=v] that updates the i-th
  1516     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1517   - new function `upt' written [i..j(] which generates the list
  1518     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1519     bound write [i..j], which is a shorthand for [i..j+1(].
  1520   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1521 
  1522 * HOL/Arith:
  1523   - removed 'pred' (predecessor) function;
  1524   - generalized some theorems about n-1;
  1525   - many new laws about "div" and "mod";
  1526   - new laws about greatest common divisors (see theory ex/Primes);
  1527 
  1528 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1529 instead of "inverse";
  1530 
  1531 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1532   of the multiset ordering;
  1533 
  1534 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1535   (not included by default);
  1536 
  1537 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1538 
  1539 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1540   programs, i.e. different program variables may have different types.
  1541 
  1542 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1543   [previously, this check worked only if the rewrite rule was unconditional]
  1544   Now rew can involve either definitions or equalities (either == or =).
  1545 
  1546 
  1547 *** ZF ***
  1548 
  1549 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1550   only the theorems proved on ZF.ML;
  1551 
  1552 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1553   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1554   disjointness reasoning but breaking a few old proofs.
  1555 
  1556 * ZF/Update: new theory of function updates
  1557     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1558   may also be iterated as in f(a:=b,c:=d,...);
  1559 
  1560 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1561 
  1562 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1563   [previously, this check worked only if the rewrite rule was unconditional]
  1564   Now rew can involve either definitions or equalities (either == or =).
  1565 
  1566 * case_tac provided for compatibility with HOL
  1567     (like the old excluded_middle_tac, but with subgoals swapped)
  1568 
  1569 
  1570 *** Internal programming interfaces ***
  1571 
  1572 * Pure: several new basic modules made available for general use, see
  1573 also src/Pure/README;
  1574 
  1575 * improved the theory data mechanism to support encapsulation (data
  1576 kind name replaced by private Object.kind, acting as authorization
  1577 key); new type-safe user interface via functor TheoryDataFun; generic
  1578 print_data function becomes basically useless;
  1579 
  1580 * removed global_names compatibility flag -- all theory declarations
  1581 are qualified by default;
  1582 
  1583 * module Pure/Syntax now offers quote / antiquote translation
  1584 functions (useful for Hoare logic etc. with implicit dependencies);
  1585 see HOL/ex/Antiquote for an example use;
  1586 
  1587 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1588 cterm -> thm;
  1589 
  1590 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1591 subgoal;
  1592 
  1593 * Display.print_goals function moved to Locale.print_goals;
  1594 
  1595 * standard print function for goals supports current_goals_markers
  1596 variable for marking begin of proof, end of proof, start of goal; the
  1597 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1598 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1599 for example;
  1600 
  1601 
  1602 
  1603 New in Isabelle98 (January 1998)
  1604 --------------------------------
  1605 
  1606 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1607 
  1608 * changed lexical syntax of terms / types: dots made part of long
  1609 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1610 
  1611 * simpset (and claset) reference variable replaced by functions
  1612 simpset / simpset_ref;
  1613 
  1614 * no longer supports theory aliases (via merge) and non-trivial
  1615 implicit merge of thms' signatures;
  1616 
  1617 * most internal names of constants changed due to qualified names;
  1618 
  1619 * changed Pure/Sequence interface (see Pure/seq.ML);
  1620 
  1621 
  1622 *** General Changes ***
  1623 
  1624 * hierachically structured name spaces (for consts, types, axms, thms
  1625 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1626 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1627 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1628 long_names for fully qualified output names; NOTE: ML programs
  1629 (special tactics, packages etc.) referring to internal names may have
  1630 to be adapted to cope with fully qualified names; in case of severe
  1631 backward campatibility problems try setting 'global_names' at compile
  1632 time to have enrything declared within a flat name space; one may also
  1633 fine tune name declarations in theories via the 'global' and 'local'
  1634 section;
  1635 
  1636 * reimplemented the implicit simpset and claset using the new anytype
  1637 data filed in signatures; references simpset:simpset ref etc. are
  1638 replaced by functions simpset:unit->simpset and
  1639 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1640 to patch your ML files accordingly;
  1641 
  1642 * HTML output now includes theory graph data for display with Java
  1643 applet or isatool browser; data generated automatically via isatool
  1644 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1645 
  1646 * defs may now be conditional; improved rewrite_goals_tac to handle
  1647 conditional equations;
  1648 
  1649 * defs now admits additional type arguments, using TYPE('a) syntax;
  1650 
  1651 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1652 creates a new theory node; implicit merge of thms' signatures is
  1653 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1654 transfer:theory->thm->thm in (rare) cases;
  1655 
  1656 * improved handling of draft signatures / theories; draft thms (and
  1657 ctyps, cterms) are automatically promoted to real ones;
  1658 
  1659 * slightly changed interfaces for oracles: admit many per theory, named
  1660 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1661 
  1662 * print_goals: optional output of const types (set show_consts and
  1663 show_types);
  1664 
  1665 * improved output of warnings (###) and errors (***);
  1666 
  1667 * subgoal_tac displays a warning if the new subgoal has type variables;
  1668 
  1669 * removed old README and Makefiles;
  1670 
  1671 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1672 
  1673 * removed obsolete init_pps and init_database;
  1674 
  1675 * deleted the obsolete tactical STATE, which was declared by
  1676     fun STATE tacfun st = tacfun st st;
  1677 
  1678 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1679 (which abbreviates $HOME);
  1680 
  1681 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1682 use isatool fixseq to adapt your ML programs (this works for fully
  1683 qualified references to the Sequence structure only!);
  1684 
  1685 * use_thy no longer requires writable current directory; it always
  1686 reloads .ML *and* .thy file, if either one is out of date;
  1687 
  1688 
  1689 *** Classical Reasoner ***
  1690 
  1691 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1692 tactics that use classical reasoning to simplify a subgoal without
  1693 splitting it into several subgoals;
  1694 
  1695 * Safe_tac: like safe_tac but uses the default claset;
  1696 
  1697 
  1698 *** Simplifier ***
  1699 
  1700 * added simplification meta rules:
  1701     (asm_)(full_)simplify: simpset -> thm -> thm;
  1702 
  1703 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1704 logics (again);
  1705 
  1706 * added prems argument to simplification procedures;
  1707 
  1708 * HOL, FOL, ZF: added infix function `addsplits':
  1709   instead of `<simpset> setloop (split_tac <thms>)'
  1710   you can simply write `<simpset> addsplits <thms>'
  1711 
  1712 
  1713 *** Syntax ***
  1714 
  1715 * TYPE('a) syntax for type reflection terms;
  1716 
  1717 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1718 
  1719 * pretty printer: changed order of mixfix annotation preference (again!);
  1720 
  1721 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1722 
  1723 
  1724 *** HOL ***
  1725 
  1726 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1727   with `addloop' of the simplifier to faciliate case splitting in premises.
  1728 
  1729 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1730 
  1731 * HOL/Auth: new protocol proofs including some for the Internet
  1732   protocol TLS;
  1733 
  1734 * HOL/Map: new theory of `maps' a la VDM;
  1735 
  1736 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1737 cancelling out common nat summands from =, <, <= (in)equalities, or
  1738 differences; simplification procedures nat_cancel_factor for
  1739 cancelling common factor from =, <, <= (in)equalities over natural
  1740 sums; nat_cancel contains both kinds of procedures, it is installed by
  1741 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1742 
  1743 * HOL/simplifier: terms of the form
  1744   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1745   are rewritten to
  1746   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1747   and those of the form
  1748   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1749   are rewritten to
  1750   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1751 
  1752 * HOL/datatype
  1753   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1754 
  1755   P(t_case f1 ... fn x) =
  1756      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1757         ...
  1758        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1759      )
  1760 
  1761   and a theorem `split_t_case_asm' of the form
  1762 
  1763   P(t_case f1 ... fn x) =
  1764     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1765         ...
  1766        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1767      )
  1768   which can be added to a simpset via `addsplits'. The existing theorems
  1769   expand_list_case and expand_option_case have been renamed to
  1770   split_list_case and split_option_case.
  1771 
  1772 * HOL/Arithmetic:
  1773   - `pred n' is automatically converted to `n-1'.
  1774     Users are strongly encouraged not to use `pred' any longer,
  1775     because it will disappear altogether at some point.
  1776   - Users are strongly encouraged to write "0 < n" rather than
  1777     "n ~= 0". Theorems and proof tools have been modified towards this
  1778     `standard'.
  1779 
  1780 * HOL/Lists:
  1781   the function "set_of_list" has been renamed "set" (and its theorems too);
  1782   the function "nth" now takes its arguments in the reverse order and
  1783   has acquired the infix notation "!" as in "xs!n".
  1784 
  1785 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1786 
  1787 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1788   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1789 
  1790 * HOL/record: extensible records with schematic structural subtyping
  1791 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1792 still lacks various theorems and concrete record syntax;
  1793 
  1794 
  1795 *** HOLCF ***
  1796 
  1797 * removed "axioms" and "generated by" sections;
  1798 
  1799 * replaced "ops" section by extended "consts" section, which is capable of
  1800   handling the continuous function space "->" directly;
  1801 
  1802 * domain package:
  1803   . proves theorems immediately and stores them in the theory,
  1804   . creates hierachical name space,
  1805   . now uses normal mixfix annotations (instead of cinfix...),
  1806   . minor changes to some names and values (for consistency),
  1807   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1808   . separator between mutual domain defs: changed "," to "and",
  1809   . improved handling of sort constraints;  now they have to
  1810     appear on the left-hand side of the equations only;
  1811 
  1812 * fixed LAM <x,y,zs>.b syntax;
  1813 
  1814 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1815 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1816 
  1817 
  1818 *** FOL and ZF ***
  1819 
  1820 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1821   with `addloop' of the simplifier to faciliate case splitting in premises.
  1822 
  1823 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1824 in HOL, they strip ALL and --> from proved theorems;
  1825 
  1826 
  1827 
  1828 New in Isabelle94-8 (May 1997)
  1829 ------------------------------
  1830 
  1831 *** General Changes ***
  1832 
  1833 * new utilities to build / run / maintain Isabelle etc. (in parts
  1834 still somewhat experimental); old Makefiles etc. still functional;
  1835 
  1836 * new 'Isabelle System Manual';
  1837 
  1838 * INSTALL text, together with ./configure and ./build scripts;
  1839 
  1840 * reimplemented type inference for greater efficiency, better error
  1841 messages and clean internal interface;
  1842 
  1843 * prlim command for dealing with lots of subgoals (an easier way of
  1844 setting goals_limit);
  1845 
  1846 
  1847 *** Syntax ***
  1848 
  1849 * supports alternative (named) syntax tables (parser and pretty
  1850 printer); internal interface is provided by add_modesyntax(_i);
  1851 
  1852 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1853 be used in conjunction with the Isabelle symbol font; uses the
  1854 "symbols" syntax table;
  1855 
  1856 * added token_translation interface (may translate name tokens in
  1857 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1858 the current print_mode); IMPORTANT: user print translation functions
  1859 are responsible for marking newly introduced bounds
  1860 (Syntax.mark_boundT);
  1861 
  1862 * token translations for modes "xterm" and "xterm_color" that display
  1863 names in bold, underline etc. or colors (which requires a color
  1864 version of xterm);
  1865 
  1866 * infixes may now be declared with names independent of their syntax;
  1867 
  1868 * added typed_print_translation (like print_translation, but may
  1869 access type of constant);
  1870 
  1871 
  1872 *** Classical Reasoner ***
  1873 
  1874 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1875 some limitations.  Blast_tac...
  1876   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1877   + ignores elimination rules that don't have the correct format
  1878         (the conclusion MUST be a formula variable)
  1879   + ignores types, which can make HOL proofs fail
  1880   + rules must not require higher-order unification, e.g. apply_type in ZF
  1881     [message "Function Var's argument not a bound variable" relates to this]
  1882   + its proof strategy is more general but can actually be slower
  1883 
  1884 * substitution with equality assumptions no longer permutes other
  1885 assumptions;
  1886 
  1887 * minor changes in semantics of addafter (now called addaltern); renamed
  1888 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1889 (and access functions for it);
  1890 
  1891 * improved combination of classical reasoner and simplifier:
  1892   + functions for handling clasimpsets
  1893   + improvement of addss: now the simplifier is called _after_ the
  1894     safe steps.
  1895   + safe variant of addss called addSss: uses safe simplifications
  1896     _during_ the safe steps. It is more complete as it allows multiple
  1897     instantiations of unknowns (e.g. with slow_tac).
  1898 
  1899 *** Simplifier ***
  1900 
  1901 * added interface for simplification procedures (functions that
  1902 produce *proven* rewrite rules on the fly, depending on current
  1903 redex);
  1904 
  1905 * ordering on terms as parameter (used for ordered rewriting);
  1906 
  1907 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1908 
  1909 * the solver is now split into a safe and an unsafe part.
  1910 This should be invisible for the normal user, except that the
  1911 functions setsolver and addsolver have been renamed to setSolver and
  1912 addSolver; added safe_asm_full_simp_tac;
  1913 
  1914 
  1915 *** HOL ***
  1916 
  1917 * a generic induction tactic `induct_tac' which works for all datatypes and
  1918 also for type `nat';
  1919 
  1920 * a generic case distinction tactic `exhaust_tac' which works for all
  1921 datatypes and also for type `nat';
  1922 
  1923 * each datatype comes with a function `size';
  1924 
  1925 * patterns in case expressions allow tuple patterns as arguments to
  1926 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1927 
  1928 * primrec now also works with type nat;
  1929 
  1930 * recdef: a new declaration form, allows general recursive functions to be
  1931 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1932 
  1933 * the constant for negation has been renamed from "not" to "Not" to
  1934 harmonize with FOL, ZF, LK, etc.;
  1935 
  1936 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1937 infinite lists;
  1938 
  1939 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1940 
  1941 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1942 problems in commutative rings, using axiomatic type classes for + and *;
  1943 
  1944 * more examples in HOL/MiniML and HOL/Auth;
  1945 
  1946 * more default rewrite rules for quantifiers, union/intersection;
  1947 
  1948 * a new constant `arbitrary == @x.False';
  1949 
  1950 * HOLCF/IOA replaces old HOL/IOA;
  1951 
  1952 * HOLCF changes: derived all rules and arities
  1953   + axiomatic type classes instead of classes
  1954   + typedef instead of faking type definitions
  1955   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1956   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1957   + eliminated the types void, one, tr
  1958   + use unit lift and bool lift (with translations) instead of one and tr
  1959   + eliminated blift from Lift3.thy (use Def instead of blift)
  1960   all eliminated rules are derived as theorems --> no visible changes ;
  1961 
  1962 
  1963 *** ZF ***
  1964 
  1965 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1966 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1967 as ZF_cs addSIs [equalityI];
  1968 
  1969 
  1970 
  1971 New in Isabelle94-7 (November 96)
  1972 ---------------------------------
  1973 
  1974 * allowing negative levels (as offsets) in prlev and choplev;
  1975 
  1976 * super-linear speedup for large simplifications;
  1977 
  1978 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1979 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1980 FAIL); can suppress it using the command Delsimps (ex_simps @
  1981 all_simps); De Morgan laws are also now included, by default;
  1982 
  1983 * improved printing of ==>  :  ~:
  1984 
  1985 * new object-logic "Sequents" adds linear logic, while replacing LK
  1986 and Modal (thanks to Sara Kalvala);
  1987 
  1988 * HOL/Auth: correctness proofs for authentication protocols;
  1989 
  1990 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1991 examples on HOL/Auth);
  1992 
  1993 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1994 the rewriter and classical reasoner simultaneously;
  1995 
  1996 * function uresult no longer returns theorems in "standard" format;
  1997 regain previous version by: val uresult = standard o uresult;
  1998 
  1999 
  2000 
  2001 New in Isabelle94-6
  2002 -------------------
  2003 
  2004 * oracles -- these establish an interface between Isabelle and trusted
  2005 external reasoners, which may deliver results as theorems;
  2006 
  2007 * proof objects (in particular record all uses of oracles);
  2008 
  2009 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2010 
  2011 * "constdefs" section in theory files;
  2012 
  2013 * "primrec" section (HOL) no longer requires names;
  2014 
  2015 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2016 
  2017 
  2018 
  2019 New in Isabelle94-5
  2020 -------------------
  2021 
  2022 * reduced space requirements;
  2023 
  2024 * automatic HTML generation from theories;
  2025 
  2026 * theory files no longer require "..." (quotes) around most types;
  2027 
  2028 * new examples, including two proofs of the Church-Rosser theorem;
  2029 
  2030 * non-curried (1994) version of HOL is no longer distributed;
  2031 
  2032 
  2033 
  2034 New in Isabelle94-4
  2035 -------------------
  2036 
  2037 * greatly reduced space requirements;
  2038 
  2039 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2040 
  2041 * searchable theorem database (see the section "Retrieving theorems" on
  2042 page 8 of the Reference Manual);
  2043 
  2044 * new examples, including Grabczewski's monumental case study of the
  2045 Axiom of Choice;
  2046 
  2047 * The previous version of HOL renamed to Old_HOL;
  2048 
  2049 * The new version of HOL (previously called CHOL) uses a curried syntax
  2050 for functions.  Application looks like f a b instead of f(a,b);
  2051 
  2052 * Mutually recursive inductive definitions finally work in HOL;
  2053 
  2054 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2055 translates to the operator "split";
  2056 
  2057 
  2058 
  2059 New in Isabelle94-3
  2060 -------------------
  2061 
  2062 * new infix operator, addss, allowing the classical reasoner to
  2063 perform simplification at each step of its search.  Example:
  2064         fast_tac (cs addss ss)
  2065 
  2066 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2067 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2068 look like (a,b) instead of <a,b>;
  2069 
  2070 * PLEASE NOTE: CHOL will eventually replace HOL!
  2071 
  2072 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2073 It translates to the operator "split".  A new theory of integers is available;
  2074 
  2075 * In ZF, integer numerals now denote two's-complement binary integers.
  2076 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2077 
  2078 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2079 of the Axiom of Choice;
  2080 
  2081 
  2082 
  2083 New in Isabelle94-2
  2084 -------------------
  2085 
  2086 * Significantly faster resolution;
  2087 
  2088 * the different sections in a .thy file can now be mixed and repeated
  2089 freely;
  2090 
  2091 * Database of theorems for FOL, HOL and ZF.  New
  2092 commands including qed, qed_goal and bind_thm store theorems in the database.
  2093 
  2094 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2095 a given theory (thms_of), or find out what theory a theorem was proved in
  2096 (theory_of_thm);
  2097 
  2098 * Bugs fixed in the inductive definition and datatype packages;
  2099 
  2100 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2101 and HOL_dup_cs obsolete;
  2102 
  2103 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2104 have been removed;
  2105 
  2106 * Simpler definition of function space in ZF;
  2107 
  2108 * new results about cardinal and ordinal arithmetic in ZF;
  2109 
  2110 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2111 types;
  2112 
  2113 
  2114 $Id$