NEWS
author wenzelm
Sun Oct 21 19:44:25 2001 +0200 (2001-10-21)
changeset 11864 371ce685b0ec
parent 11842 b903d3dabbe2
child 11899 e543b0f01a58
permissions -rw-r--r--
* proper spacing of consecutive markup elements, especially text
blocks after section headings;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol;
    31 
    32 
    33 *** Isar ***
    34 
    35 * improved proof by cases and induction:
    36   - 'case' command admits impromptu naming of parameters (such as
    37     "case (Suc n)");
    38   - 'induct' method divinates rule instantiation from the inductive
    39     claim; no longer requires excessive ?P bindings for proper
    40     instantiation of cases;
    41   - 'induct' method properly enumerates all possibilities of set/type
    42     rules; as a consequence facts may be also passed through *type*
    43     rules without further ado;
    44   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    45   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    46   - moved induct/cases attributes to Pure, methods to Provers;
    47   - generic method setup instantiated for FOL and HOL;
    48 
    49 * Pure: renamed "antecedent" case to "rule_context";
    50 
    51 * Pure: added 'corollary' command;
    52 
    53 * Pure: fixed 'token_translation' command;
    54 
    55 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    56 
    57 * HOL: 'recdef' now fails on unfinished automated proofs, use
    58 "(permissive)" option to recover old behavior;
    59 
    60 * HOL: 'inductive' now longer features separate (collective)
    61 attributes for 'intros';
    62 
    63 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
    64 
    65 
    66 *** HOL ***
    67 
    68 * HOL: moved over to sane numeral syntax; the new policy is as
    69 follows:
    70 
    71   - 0 and 1 are polymorphic constants, which are defined on any
    72   numeric type (nat, int, real etc.);
    73 
    74   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    75   binary representation internally;
    76 
    77   - type nat has special constructor Suc, and generally prefers Suc 0
    78   over 1::nat and Suc (Suc 0) over 2::nat;
    79 
    80 This change may cause significant INCOMPATIBILITIES; here are some
    81 hints on converting existing sources:
    82 
    83   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    84   entities, so expressions involving "-" (unary or binary minus) need
    85   to be spaced properly;
    86 
    87   - existing occurrences of "1" may need to be constraint "1::nat" or
    88   even replaced by Suc 0; similar for old "2";
    89 
    90   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
    91 
    92   - remove all special provisions on numerals in proofs;
    93 
    94 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
    95 (beware of argument permutation!);
    96 
    97 * HOL: linorder_less_split superseded by linorder_cases;
    98 
    99 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   100 to peripheral theory "Hilbert_Choice";
   101 
   102 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   103 in this (rare) case use:
   104 
   105   delSWrapper "split_all_tac"
   106   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   107 
   108 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   109 MAY FAIL;
   110 
   111 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   112 Isabelle's type classes, ^ on functions and relations has too general
   113 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   114 necessary to attach explicit type constraints;
   115 
   116 * HOL: syntax translations now work properly with numerals and records
   117 expressions;
   118 
   119 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   120 Florian Kammüller;
   121 
   122 * HOL: eliminated global items
   123 
   124   const "()" -> "Product_Type.Unity"
   125   type "unit" -> "Product_Type.unit"
   126 
   127 
   128 *** ZF ***
   129 
   130 * ZF: the integer library now covers quotients and remainders, with
   131 many laws relating division to addition, multiplication, etc.;
   132 
   133 
   134 *** General ***
   135 
   136 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   137 manual;
   138 
   139 * classical reasoner: renamed addaltern to addafter, addSaltern to
   140 addSafter;
   141 
   142 * syntax: new token syntax "num" for plain numerals (without "#" of
   143 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   144 tokens, so expressions involving minus need to be spaced properly;
   145 
   146 * syntax: support non-oriented infixes;
   147 
   148 * syntax: print modes "type_brackets" and "no_type_brackets" control
   149 output of nested => (types); the default behavior is "type_brackets";
   150 
   151 * syntax: builtin parse translation for "_constify" turns valued
   152 tokens into AST constants;
   153 
   154 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   155 
   156 * system: Proof General keywords specification is now part of the
   157 Isabelle distribution (see etc/isar-keywords.el);
   158 
   159 * system: smart selection of Isabelle process versus Isabelle
   160 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   161 run both "isabelle" and "Isabelle" even if file names are badly
   162 damaged (executable inspects the case of the first letter of its own
   163 name); added separate "isabelle-process" and "isabelle-interface";
   164 
   165 
   166 
   167 New in Isabelle99-2 (February 2001)
   168 -----------------------------------
   169 
   170 *** Overview of INCOMPATIBILITIES ***
   171 
   172 * HOL: please note that theories in the Library and elsewhere often use the
   173 new-style (Isar) format; to refer to their theorems in an ML script you must
   174 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   175 
   176 * HOL: inductive package no longer splits induction rule aggressively,
   177 but only as far as specified by the introductions given; the old
   178 format may be recovered via ML function complete_split_rule or attribute
   179 'split_rule (complete)';
   180 
   181 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   182 gfp_Tarski to gfp_unfold;
   183 
   184 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   185 
   186 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   187 relation); infix "^^" has been renamed "``"; infix "``" has been
   188 renamed "`"; "univalent" has been renamed "single_valued";
   189 
   190 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   191 operation;
   192 
   193 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   194 
   195 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   196 
   197 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   198 consequence, it is no longer monotonic wrt. the local goal context
   199 (which is now passed through the inductive cases);
   200 
   201 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   202 \<gg> to \<ggreater>;
   203 
   204 
   205 *** Document preparation ***
   206 
   207 * \isabellestyle{NAME} selects version of Isabelle output (currently
   208 available: are "it" for near math-mode best-style output, "sl" for
   209 slanted text style, and "tt" for plain type-writer; if no
   210 \isabellestyle command is given, output is according to slanted
   211 type-writer);
   212 
   213 * support sub/super scripts (for single symbols only), input syntax is
   214 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   215 
   216 * some more standard symbols; see Appendix A of the system manual for
   217 the complete list of symbols defined in isabellesym.sty;
   218 
   219 * improved isabelle style files; more abstract symbol implementation
   220 (should now use \isamath{...} and \isatext{...} in custom symbol
   221 definitions);
   222 
   223 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   224 state; Note that presentation of goal states does not conform to
   225 actual human-readable proof documents.  Please do not include goal
   226 states into document output unless you really know what you are doing!
   227 
   228 * proper indentation of antiquoted output with proportional LaTeX
   229 fonts;
   230 
   231 * no_document ML operator temporarily disables LaTeX document
   232 generation;
   233 
   234 * isatool unsymbolize tunes sources for plain ASCII communication;
   235 
   236 
   237 *** Isar ***
   238 
   239 * Pure: Isar now suffers initial goal statements to contain unbound
   240 schematic variables (this does not conform to actual readable proof
   241 documents, due to unpredictable outcome and non-compositional proof
   242 checking); users who know what they are doing may use schematic goals
   243 for Prolog-style synthesis of proven results;
   244 
   245 * Pure: assumption method (an implicit finishing) now handles actual
   246 rules as well;
   247 
   248 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   249 initial goal, declare "that" only as Pure intro (only for single
   250 steps); the "that" rule assumption may now be involved in implicit
   251 finishing, thus ".." becomes a feasible for trivial obtains;
   252 
   253 * Pure: default proof step now includes 'intro_classes'; thus trivial
   254 instance proofs may be performed by "..";
   255 
   256 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   257 statements as well;
   258 
   259 * Pure: more robust selection of calculational rules;
   260 
   261 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   262 rule (as well as the assumption rule);
   263 
   264 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   265 lemmas, using the graph browser tool;
   266 
   267 * Pure: predict failure of "show" in interactive mode;
   268 
   269 * Pure: 'thms_containing' now takes actual terms as arguments;
   270 
   271 * HOL: improved method 'induct' --- now handles non-atomic goals
   272 (potential INCOMPATIBILITY); tuned error handling;
   273 
   274 * HOL: cases and induct rules now provide explicit hints about the
   275 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   276 any remaining facts are inserted into the goal verbatim;
   277 
   278 * HOL: local contexts (aka cases) may now contain term bindings as
   279 well; the 'cases' and 'induct' methods new provide a ?case binding for
   280 the result to be shown in each case;
   281 
   282 * HOL: added 'recdef_tc' command;
   283 
   284 * isatool convert assists in eliminating legacy ML scripts;
   285 
   286 
   287 *** HOL ***
   288 
   289 * HOL/Library: a collection of generic theories to be used together
   290 with main HOL; the theory loader path already includes this directory
   291 by default; the following existing theories have been moved here:
   292 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   293 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   294 
   295 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   296 modelling and verification task performed in Isabelle/HOL +
   297 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   298 
   299 * HOL/Algebra: special summation operator SUM no longer exists, it has
   300 been replaced by setsum; infix 'assoc' now has priority 50 (like
   301 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   302 'domain', this makes the theory consistent with mathematical
   303 literature;
   304 
   305 * HOL basics: added overloaded operations "inverse" and "divide"
   306 (infix "/"), syntax for generic "abs" operation, generic summation
   307 operator \<Sum>;
   308 
   309 * HOL/typedef: simplified package, provide more useful rules (see also
   310 HOL/subset.thy);
   311 
   312 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   313 now expressed as a proper nested rule (old-style tactic scripts may
   314 require atomize_strip_tac to cope with non-atomic premises);
   315 
   316 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   317 to "split_conv" (old name still available for compatibility);
   318 
   319 * HOL: improved concrete syntax for strings (e.g. allows translation
   320 rules with string literals);
   321 
   322 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   323 and Fleuriot's mechanization of analysis;
   324 
   325 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   326 
   327 
   328 *** CTT ***
   329 
   330 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   331 "lam" is displayed as TWO lambda-symbols
   332 
   333 * CTT: theory Main now available, containing everything (that is, Bool
   334 and Arith);
   335 
   336 
   337 *** General ***
   338 
   339 * Pure: the Simplifier has been implemented properly as a derived rule
   340 outside of the actual kernel (at last!); the overall performance
   341 penalty in practical applications is about 50%, while reliability of
   342 the Isabelle inference kernel has been greatly improved;
   343 
   344 * print modes "brackets" and "no_brackets" control output of nested =>
   345 (types) and ==> (props); the default behaviour is "brackets";
   346 
   347 * Provers: fast_tac (and friends) now handle actual object-logic rules
   348 as assumptions as well;
   349 
   350 * system: support Poly/ML 4.0;
   351 
   352 * system: isatool install handles KDE version 1 or 2;
   353 
   354 
   355 
   356 New in Isabelle99-1 (October 2000)
   357 ----------------------------------
   358 
   359 *** Overview of INCOMPATIBILITIES ***
   360 
   361 * HOL: simplification of natural numbers is much changed; to partly
   362 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   363 issue the following ML commands:
   364 
   365   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   366   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   367 
   368 * HOL: simplification no longer dives into case-expressions; this is
   369 controlled by "t.weak_case_cong" for each datatype t;
   370 
   371 * HOL: nat_less_induct renamed to less_induct;
   372 
   373 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   374 fixsome to patch .thy and .ML sources automatically;
   375 
   376   select_equality  -> some_equality
   377   select_eq_Ex     -> some_eq_ex
   378   selectI2EX       -> someI2_ex
   379   selectI2         -> someI2
   380   selectI          -> someI
   381   select1_equality -> some1_equality
   382   Eps_sym_eq       -> some_sym_eq_trivial
   383   Eps_eq           -> some_eq_trivial
   384 
   385 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   386 
   387 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   388 instead);
   389 
   390 * HOL: the recursion equations generated by 'recdef' are now called
   391 f.simps instead of f.rules;
   392 
   393 * HOL: qed_spec_mp now also handles bounded ALL as well;
   394 
   395 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   396 sometimes be needed;
   397 
   398 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   399 
   400 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   401 
   402 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   403 product is now "<*>" instead of "Times"; the lexicographic product is
   404 now "<*lex*>" instead of "**";
   405 
   406 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   407 of main HOL, but was unused); better use HOL's datatype package;
   408 
   409 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   410 the old syntax may be recovered as follows:
   411 
   412   syntax (symbols)
   413     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   414       (infixl "\\<oplus>" 100)
   415 
   416 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   417 
   418 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   419 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   420 internally;
   421 
   422 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   423 changed from A/r to A//r;
   424 
   425 * ZF: new treatment of arithmetic (nat & int) may break some old
   426 proofs;
   427 
   428 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   429 rulify -> rule_format, elimify -> elim_format, ...);
   430 
   431 * Isar/Provers: intro/elim/dest attributes changed; renamed
   432 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   433 should have to change intro!! to intro? only); replaced "delrule" by
   434 "rule del";
   435 
   436 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   437 
   438 * Provers: strengthened force_tac by using new first_best_tac;
   439 
   440 * LaTeX document preparation: several changes of isabelle.sty (see
   441 lib/texinputs);
   442 
   443 
   444 *** Document preparation ***
   445 
   446 * formal comments (text blocks etc.) in new-style theories may now
   447 contain antiquotations of thm/prop/term/typ/text to be presented
   448 according to latex print mode; concrete syntax is like this:
   449 @{term[show_types] "f(x) = a + x"};
   450 
   451 * isatool mkdir provides easy setup of Isabelle session directories,
   452 including proper document sources;
   453 
   454 * generated LaTeX sources are now deleted after successful run
   455 (isatool document -c); may retain a copy somewhere else via -D option
   456 of isatool usedir;
   457 
   458 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   459 style files, achieving self-contained LaTeX sources and simplifying
   460 LaTeX debugging;
   461 
   462 * old-style theories now produce (crude) LaTeX output as well;
   463 
   464 * browser info session directories are now self-contained (may be put
   465 on WWW server seperately); improved graphs of nested sessions; removed
   466 graph for 'all sessions';
   467 
   468 * several improvements in isabelle style files; \isabellestyle{it}
   469 produces fake math mode output; \isamarkupheader is now \section by
   470 default; see lib/texinputs/isabelle.sty etc.;
   471 
   472 
   473 *** Isar ***
   474 
   475 * Isar/Pure: local results and corresponding term bindings are now
   476 subject to Hindley-Milner polymorphism (similar to ML); this
   477 accommodates incremental type-inference very nicely;
   478 
   479 * Isar/Pure: new derived language element 'obtain' supports
   480 generalized existence reasoning;
   481 
   482 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   483 support accumulation of results, without applying any rules yet;
   484 useful to collect intermediate results without explicit name
   485 references, and for use with transitivity rules with more than 2
   486 premises;
   487 
   488 * Isar/Pure: scalable support for case-analysis type proofs: new
   489 'case' language element refers to local contexts symbolically, as
   490 produced by certain proof methods; internally, case names are attached
   491 to theorems as "tags";
   492 
   493 * Isar/Pure: theory command 'hide' removes declarations from
   494 class/type/const name spaces;
   495 
   496 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   497 indicate potential overloading;
   498 
   499 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   500 
   501 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   502 "{a,b,c}" instead of {a,b,c};
   503 
   504 * Isar/Pure now provides its own version of intro/elim/dest
   505 attributes; useful for building new logics, but beware of confusion
   506 with the version in Provers/classical;
   507 
   508 * Isar/Pure: the local context of (non-atomic) goals is provided via
   509 case name 'antecedent';
   510 
   511 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   512 to the current context is now done automatically);
   513 
   514 * Isar/Pure: theory command 'method_setup' provides a simple interface
   515 for definining proof methods in ML;
   516 
   517 * Isar/Provers: intro/elim/dest attributes changed; renamed
   518 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   519 most cases, one should have to change intro!! to intro? only);
   520 replaced "delrule" by "rule del";
   521 
   522 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   523 'symmetric' attribute (the latter supercedes [RS sym]);
   524 
   525 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   526 method modifier); 'simp' method: 'only:' modifier removes loopers as
   527 well (including splits);
   528 
   529 * Isar/Provers: Simplifier and Classical methods now support all kind
   530 of modifiers used in the past, including 'cong', 'iff', etc.
   531 
   532 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   533 of Simplifier and Classical reasoner);
   534 
   535 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   536 now support named cases; major packages (inductive, datatype, primrec,
   537 recdef) support case names and properly name parameters;
   538 
   539 * Isar/HOL: new transitivity rules for substitution in inequalities --
   540 monotonicity conditions are extracted to be proven at end of
   541 calculations;
   542 
   543 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   544 method anyway;
   545 
   546 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   547 split_if split_if_asm; datatype package provides theorems foo.splits =
   548 foo.split foo.split_asm for each datatype;
   549 
   550 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   551 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   552 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   553 use "(cases (simplified))" method in proper proof texts);
   554 
   555 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   556 
   557 * Isar: names of theorems etc. may be natural numbers as well;
   558 
   559 * Isar: 'pr' command: optional arguments for goals_limit and
   560 ProofContext.prems_limit; no longer prints theory contexts, but only
   561 proof states;
   562 
   563 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   564 additional print modes to be specified; e.g. "pr(latex)" will print
   565 proof state according to the Isabelle LaTeX style;
   566 
   567 * Isar: improved support for emulating tactic scripts, including proof
   568 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   569 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   570 (for HOL datatypes);
   571 
   572 * Isar: simplified (more robust) goal selection of proof methods: 1st
   573 goal, all goals, or explicit goal specifier (tactic emulation); thus
   574 'proof method scripts' have to be in depth-first order;
   575 
   576 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   577 
   578 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   579 should instead use individual commands for printing items
   580 (print_commands, print_methods etc.);
   581 
   582 * Isar: added 'nothing' --- the empty list of theorems;
   583 
   584 
   585 *** HOL ***
   586 
   587 * HOL/MicroJava: formalization of a fragment of Java, together with a
   588 corresponding virtual machine and a specification of its bytecode
   589 verifier and a lightweight bytecode verifier, including proofs of
   590 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   591 Cornelia Pusch (see also the homepage of project Bali at
   592 http://isabelle.in.tum.de/Bali/);
   593 
   594 * HOL/Algebra: new theory of rings and univariate polynomials, by
   595 Clemens Ballarin;
   596 
   597 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   598 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   599 Rasmussen;
   600 
   601 * HOL/Lattice: fundamental concepts of lattice theory and order
   602 structures, including duals, properties of bounds versus algebraic
   603 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   604 Theorem for complete lattices etc.; may also serve as a demonstration
   605 for abstract algebraic reasoning using axiomatic type classes, and
   606 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   607 
   608 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   609 von Oheimb;
   610 
   611 * HOL/IMPP: extension of IMP with local variables and mutually
   612 recursive procedures, by David von Oheimb;
   613 
   614 * HOL/Lambda: converted into new-style theory and document;
   615 
   616 * HOL/ex/Multiquote: example of multiple nested quotations and
   617 anti-quotations -- basically a generalized version of de-Bruijn
   618 representation; very useful in avoiding lifting of operations;
   619 
   620 * HOL/record: added general record equality rule to simpset; fixed
   621 select-update simplification procedure to handle extended records as
   622 well; admit "r" as field name;
   623 
   624 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   625 other numeric types and also as the identity of groups, rings, etc.;
   626 
   627 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   628 Types nat and int belong to this axclass;
   629 
   630 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   631    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   632    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   633   two terms #m*u and #n*u are replaced by #(m+n)*u
   634     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   635   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   636     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   637 
   638 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   639 powerful prover for predicate logic but knows nothing of clasets; see
   640 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   641 
   642 * HOL: new version of "case_tac" subsumes both boolean case split and
   643 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   644 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   645 
   646 * HOL: simplification no longer dives into case-expressions: only the
   647 selector expression is simplified, but not the remaining arms; to
   648 enable full simplification of case-expressions for datatype t, you may
   649 remove t.weak_case_cong from the simpset, either globally (Delcongs
   650 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   651 
   652 * HOL/recdef: the recursion equations generated by 'recdef' for
   653 function 'f' are now called f.simps instead of f.rules; if all
   654 termination conditions are proved automatically, these simplification
   655 rules are added to the simpset, as in primrec; rules may be named
   656 individually as well, resulting in a separate list of theorems for
   657 each equation;
   658 
   659 * HOL/While is a new theory that provides a while-combinator. It
   660 permits the definition of tail-recursive functions without the
   661 provision of a termination measure. The latter is necessary once the
   662 invariant proof rule for while is applied.
   663 
   664 * HOL: new (overloaded) notation for the set of elements below/above
   665 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   666 
   667 * HOL: theorems impI, allI, ballI bound as "strip";
   668 
   669 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   670 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   671 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   672 
   673 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   674 
   675 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   676 main HOL, but was unused);
   677 
   678 * HOL: fewer consts declared as global (e.g. have to refer to
   679 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   680 
   681 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   682 in case of overlap with user translations (e.g. judgements over
   683 tuples); (note that the underlying logical represenation is still
   684 bogus);
   685 
   686 
   687 *** ZF ***
   688 
   689 * ZF: simplification automatically cancels common terms in arithmetic
   690 expressions over nat and int;
   691 
   692 * ZF: new treatment of nat to minimize type-checking: all operators
   693 coerce their operands to a natural number using the function natify,
   694 making the algebraic laws unconditional;
   695 
   696 * ZF: as above, for int: operators coerce their operands to an integer
   697 using the function intify;
   698 
   699 * ZF: the integer library now contains many of the usual laws for the
   700 orderings, including $<=, and monotonicity laws for $+ and $*;
   701 
   702 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   703 simplification;
   704 
   705 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   706 to the simplifier and classical reasoner simultaneously;
   707 
   708 
   709 *** General ***
   710 
   711 * Provers: blast_tac now handles actual object-logic rules as
   712 assumptions; note that auto_tac uses blast_tac internally as well;
   713 
   714 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   715 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   716 
   717 * Provers: delrules now handles destruct rules as well (no longer need
   718 explicit make_elim);
   719 
   720 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   721   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   722 use instead the strong form,
   723   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   724 in HOL, FOL and ZF the function cla_make_elim will create such rules
   725 from destruct-rules;
   726 
   727 * Provers: Simplifier.easy_setup provides a fast path to basic
   728 Simplifier setup for new object-logics;
   729 
   730 * Pure: AST translation rules no longer require constant head on LHS;
   731 
   732 * Pure: improved name spaces: ambiguous output is qualified; support
   733 for hiding of names;
   734 
   735 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   736 XSYMBOL_HOME; no longer need to do manual configuration in most
   737 situations;
   738 
   739 * system: compression of ML heaps images may now be controlled via -c
   740 option of isabelle and isatool usedir (currently only observed by
   741 Poly/ML);
   742 
   743 * system: isatool installfonts may handle X-Symbol fonts as well (very
   744 useful for remote X11);
   745 
   746 * system: provide TAGS file for Isabelle sources;
   747 
   748 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   749 order;
   750 
   751 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   752 timing flag supersedes proof_timing and Toplevel.trace;
   753 
   754 * ML: new combinators |>> and |>>> for incremental transformations
   755 with secondary results (e.g. certain theory extensions):
   756 
   757 * ML: PureThy.add_defs gets additional argument to indicate potential
   758 overloading (usually false);
   759 
   760 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   761 results;
   762 
   763 
   764 
   765 New in Isabelle99 (October 1999)
   766 --------------------------------
   767 
   768 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   769 
   770 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   771 are no longer simplified.  (This allows the simplifier to unfold recursive
   772 functional programs.)  To restore the old behaviour, declare
   773 
   774     Delcongs [if_weak_cong];
   775 
   776 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   777 complement;
   778 
   779 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   780 
   781 * HOL/datatype: mutual_induct_tac no longer exists --
   782   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   783 
   784 * HOL/typedef: fixed type inference for representing set; type
   785 arguments now have to occur explicitly on the rhs as type constraints;
   786 
   787 * ZF: The con_defs part of an inductive definition may no longer refer
   788 to constants declared in the same theory;
   789 
   790 * HOL, ZF: the function mk_cases, generated by the inductive
   791 definition package, has lost an argument.  To simplify its result, it
   792 uses the default simpset instead of a supplied list of theorems.
   793 
   794 * HOL/List: the constructors of type list are now Nil and Cons;
   795 
   796 * Simplifier: the type of the infix ML functions
   797         setSSolver addSSolver setSolver addSolver
   798 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   799 for packaging solvers. A solver is created via
   800         mk_solver: string -> (thm list -> int -> tactic) -> solver
   801 where the string argument is only a comment.
   802 
   803 
   804 *** Proof tools ***
   805 
   806 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   807 decision procedure for linear arithmetic. Currently it is used for
   808 types `nat', `int', and `real' in HOL (see below); it can, should and
   809 will be instantiated for other types and logics as well.
   810 
   811 * The simplifier now accepts rewrite rules with flexible heads, eg
   812      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   813   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   814   matching.
   815 
   816 
   817 *** General ***
   818 
   819 * New Isabelle/Isar subsystem provides an alternative to traditional
   820 tactical theorem proving; together with the ProofGeneral/isar user
   821 interface it offers an interactive environment for developing human
   822 readable proof documents (Isar == Intelligible semi-automated
   823 reasoning); for further information see isatool doc isar-ref,
   824 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   825 
   826 * improved and simplified presentation of theories: better HTML markup
   827 (including colors), graph views in several sizes; isatool usedir now
   828 provides a proper interface for user theories (via -P option); actual
   829 document preparation based on (PDF)LaTeX is available as well (for
   830 new-style theories only); see isatool doc system for more information;
   831 
   832 * native support for Proof General, both for classic Isabelle and
   833 Isabelle/Isar;
   834 
   835 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   836 using the graph browser tool;
   837 
   838 * Isabelle manuals now also available as PDF;
   839 
   840 * theory loader rewritten from scratch (may not be fully
   841 bug-compatible); old loadpath variable has been replaced by show_path,
   842 add_path, del_path, reset_path functions; new operations such as
   843 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   844 isatool doc ref);
   845 
   846 * improved isatool install: option -k creates KDE application icon,
   847 option -p DIR installs standalone binaries;
   848 
   849 * added ML_PLATFORM setting (useful for cross-platform installations);
   850 more robust handling of platform specific ML images for SML/NJ;
   851 
   852 * the settings environment is now statically scoped, i.e. it is never
   853 created again in sub-processes invoked from isabelle, isatool, or
   854 Isabelle;
   855 
   856 * path element specification '~~' refers to '$ISABELLE_HOME';
   857 
   858 * in locales, the "assumes" and "defines" parts may be omitted if
   859 empty;
   860 
   861 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   862 long arrows);
   863 
   864 * new print_mode "HTML";
   865 
   866 * new flag show_tags controls display of tags of theorems (which are
   867 basically just comments that may be attached by some tools);
   868 
   869 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   870 mode and goal output format:
   871 
   872 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   873 244c244
   874 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   875 ---
   876 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   877 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   878 181c181
   879 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   880 ---
   881 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   882 
   883 * function bind_thms stores lists of theorems (cf. bind_thm);
   884 
   885 * new shorthand tactics ftac, eatac, datac, fatac;
   886 
   887 * qed (and friends) now accept "" as result name; in that case the
   888 theorem is not stored, but proper checks and presentation of the
   889 result still apply;
   890 
   891 * theorem database now also indexes constants "Trueprop", "all",
   892 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   893 
   894 
   895 *** HOL ***
   896 
   897 ** HOL arithmetic **
   898 
   899 * There are now decision procedures for linear arithmetic over nat and
   900 int:
   901 
   902 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   903 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   904 are treated as atomic; subformulae not involving type `nat' or `int'
   905 are ignored; quantified subformulae are ignored unless they are
   906 positive universal or negative existential. The tactic has to be
   907 invoked by hand and can be a little bit slow. In particular, the
   908 running time is exponential in the number of occurrences of `min' and
   909 `max', and `-' on `nat'.
   910 
   911 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   912 (negated) (in)equalities among the premises and the conclusion into
   913 account (i.e. no compound formulae) and does not know about `min' and
   914 `max', and `-' on `nat'. It is fast and is used automatically by the
   915 simplifier.
   916 
   917 NB: At the moment, these decision procedures do not cope with mixed
   918 nat/int formulae where the two parts interact, such as `m < n ==>
   919 int(m) < int(n)'.
   920 
   921 * HOL/Numeral provides a generic theory of numerals (encoded
   922 efficiently as bit strings); setup for types nat/int/real is in place;
   923 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   924 int, existing theories and proof scripts may require a few additional
   925 type constraints;
   926 
   927 * integer division and remainder can now be performed on constant
   928 arguments;
   929 
   930 * many properties of integer multiplication, division and remainder
   931 are now available;
   932 
   933 * An interface to the Stanford Validity Checker (SVC) is available through the
   934 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   935 are proved automatically.  SVC must be installed separately, and its results
   936 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   937 invocation of the underlying oracle).  For SVC see
   938   http://verify.stanford.edu/SVC
   939 
   940 * IsaMakefile: the HOL-Real target now builds an actual image;
   941 
   942 
   943 ** HOL misc **
   944 
   945 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   946 (in Isabelle/Isar) -- by Gertrud Bauer;
   947 
   948 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   949 analysis for assembly languages with subtypes;
   950 
   951 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   952 -- avoids syntactic ambiguities and treats state, transition, and
   953 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   954 changed syntax and (many) tactics;
   955 
   956 * HOL/inductive: Now also handles more general introduction rules such
   957   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   958   theorems are now maintained within the theory (maintained via the
   959   "mono" attribute);
   960 
   961 * HOL/datatype: Now also handles arbitrarily branching datatypes
   962   (using function types) such as
   963 
   964   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   965 
   966 * HOL/record: record_simproc (part of the default simpset) takes care
   967 of selectors applied to updated records; record_split_tac is no longer
   968 part of the default claset; update_defs may now be removed from the
   969 simpset in many cases; COMPATIBILITY: old behavior achieved by
   970 
   971   claset_ref () := claset() addSWrapper record_split_wrapper;
   972   Delsimprocs [record_simproc]
   973 
   974 * HOL/typedef: fixed type inference for representing set; type
   975 arguments now have to occur explicitly on the rhs as type constraints;
   976 
   977 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   978 names rather than an ML expression;
   979 
   980 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   981 supplied later.  Program schemes can be defined, such as
   982     "While B C s = (if B s then While B C (C s) else s)"
   983 where the well-founded relation can be chosen after B and C have been given.
   984 
   985 * HOL/List: the constructors of type list are now Nil and Cons;
   986 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   987 course, ML tools referring to List.list.op # etc. have to be adapted;
   988 
   989 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   990 disabled by default; run isabelle with option -m HOL to get back to
   991 the original Gordon/HOL-style output;
   992 
   993 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   994 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   995 
   996 * HOL basic syntax simplified (more orthogonal): all variants of
   997 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   998 Eps operator is provided as well: "SOME x. P[x]";
   999 
  1000 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1001 
  1002 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1003 thus available for user theories;
  1004 
  1005 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1006 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1007 time;
  1008 
  1009 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1010 several times and then mp;
  1011 
  1012 
  1013 *** LK ***
  1014 
  1015 * the notation <<...>> is now available as a notation for sequences of
  1016 formulas;
  1017 
  1018 * the simplifier is now installed
  1019 
  1020 * the axiom system has been generalized (thanks to Soren Heilmann)
  1021 
  1022 * the classical reasoner now has a default rule database
  1023 
  1024 
  1025 *** ZF ***
  1026 
  1027 * new primrec section allows primitive recursive functions to be given
  1028 directly (as in HOL) over datatypes and the natural numbers;
  1029 
  1030 * new tactics induct_tac and exhaust_tac for induction (or case
  1031 analysis) over datatypes and the natural numbers;
  1032 
  1033 * the datatype declaration of type T now defines the recursor T_rec;
  1034 
  1035 * simplification automatically does freeness reasoning for datatype
  1036 constructors;
  1037 
  1038 * automatic type-inference, with AddTCs command to insert new
  1039 type-checking rules;
  1040 
  1041 * datatype introduction rules are now added as Safe Introduction rules
  1042 to the claset;
  1043 
  1044 * the syntax "if P then x else y" is now available in addition to
  1045 if(P,x,y);
  1046 
  1047 
  1048 *** Internal programming interfaces ***
  1049 
  1050 * tuned simplifier trace output; new flag debug_simp;
  1051 
  1052 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1053 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1054 
  1055 * AxClass.axclass_tac lost the theory argument;
  1056 
  1057 * tuned current_goals_markers semantics: begin / end goal avoids
  1058 printing empty lines;
  1059 
  1060 * removed prs and prs_fn hook, which was broken because it did not
  1061 include \n in its semantics, forcing writeln to add one
  1062 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1063 string -> unit if you really want to output text without newline;
  1064 
  1065 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1066 plain output, interface builders may have to enable 'isabelle_font'
  1067 mode to get Isabelle font glyphs as before;
  1068 
  1069 * refined token_translation interface; INCOMPATIBILITY: output length
  1070 now of type real instead of int;
  1071 
  1072 * theory loader actions may be traced via new ThyInfo.add_hook
  1073 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1074 your own database of information attached to *whole* theories -- as
  1075 opposed to intra-theory data slots offered via TheoryDataFun;
  1076 
  1077 * proper handling of dangling sort hypotheses (at last!);
  1078 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1079 extra sort hypotheses that can be witnessed from the type signature;
  1080 the force_strip_shyps flag is gone, any remaining shyps are simply
  1081 left in the theorem (with a warning issued by strip_shyps_warning);
  1082 
  1083 
  1084 
  1085 New in Isabelle98-1 (October 1998)
  1086 ----------------------------------
  1087 
  1088 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1089 
  1090 * several changes of automated proof tools;
  1091 
  1092 * HOL: major changes to the inductive and datatype packages, including
  1093 some minor incompatibilities of theory syntax;
  1094 
  1095 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1096 called `inj_on';
  1097 
  1098 * HOL: removed duplicate thms in Arith:
  1099   less_imp_add_less  should be replaced by  trans_less_add1
  1100   le_imp_add_le      should be replaced by  trans_le_add1
  1101 
  1102 * HOL: unary minus is now overloaded (new type constraints may be
  1103 required);
  1104 
  1105 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1106 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1107 now taken as an integer constant.
  1108 
  1109 * Pure: ML function 'theory_of' renamed to 'theory';
  1110 
  1111 
  1112 *** Proof tools ***
  1113 
  1114 * Simplifier:
  1115   1. Asm_full_simp_tac is now more aggressive.
  1116      1. It will sometimes reorient premises if that increases their power to
  1117         simplify.
  1118      2. It does no longer proceed strictly from left to right but may also
  1119         rotate premises to achieve further simplification.
  1120      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1121      old Asm_full_simp_tac in that it does not rotate premises.
  1122   2. The simplifier now knows a little bit about nat-arithmetic.
  1123 
  1124 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1125 allows for selected deletion of wrappers, by introduction of names for
  1126 wrapper functionals.  This implies that addbefore, addSbefore,
  1127 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1128 and that adding two tactics with the same name overwrites the first
  1129 one (emitting a warning).
  1130   type wrapper = (int -> tactic) -> (int -> tactic)
  1131   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1132   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1133   delWrapper, delSWrapper: claset *  string            -> claset
  1134   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1135 
  1136 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1137 semantics; addbefore now affects only the unsafe part of step_tac
  1138 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1139 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1140 by Force_tac;
  1141 
  1142 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1143 compWrapper; added safe wrapper (and access functions for it);
  1144 
  1145 * HOL/split_all_tac is now much faster and fails if there is nothing
  1146 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1147 and the names of the automatically generated variables have changed.
  1148 split_all_tac has moved within claset() from unsafe wrappers to safe
  1149 wrappers, which means that !!-bound variables are split much more
  1150 aggressively, and safe_tac and clarify_tac now split such variables.
  1151 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1152 Note: the same holds for record_split_tac, which does the job of
  1153 split_all_tac for record fields.
  1154 
  1155 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1156 permanently to the default simpset using Addsplits just like
  1157 Addsimps. They can be removed via Delsplits just like
  1158 Delsimps. Lower-case versions are also available.
  1159 
  1160 * HOL/Simplifier: The rule split_if is now part of the default
  1161 simpset. This means that the simplifier will eliminate all occurrences
  1162 of if-then-else in the conclusion of a goal. To prevent this, you can
  1163 either remove split_if completely from the default simpset by
  1164 `Delsplits [split_if]' or remove it in a specific call of the
  1165 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1166 other case splitting rules to/from the default simpset: every datatype
  1167 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1168 t is the name of the datatype).
  1169 
  1170 * Classical reasoner / Simplifier combination: new force_tac (and
  1171 derivatives Force_tac, force) combines rewriting and classical
  1172 reasoning (and whatever other tools) similarly to auto_tac, but is
  1173 aimed to solve the given subgoal completely.
  1174 
  1175 
  1176 *** General ***
  1177 
  1178 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1179 and `goalw': the theory is no longer needed as an explicit argument -
  1180 the current theory context is used; assumptions are no longer returned
  1181 at the ML-level unless one of them starts with ==> or !!; it is
  1182 recommended to convert to these new commands using isatool fixgoal
  1183 (backup your sources first!);
  1184 
  1185 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1186 the current theory context, and 'theory' to lookup stored theories;
  1187 
  1188 * new theory section 'locale' for declaring constants, assumptions and
  1189 definitions that have local scope;
  1190 
  1191 * new theory section 'nonterminals' for purely syntactic types;
  1192 
  1193 * new theory section 'setup' for generic ML setup functions
  1194 (e.g. package initialization);
  1195 
  1196 * the distribution now includes Isabelle icons: see
  1197 lib/logo/isabelle-{small,tiny}.xpm;
  1198 
  1199 * isatool install - install binaries with absolute references to
  1200 ISABELLE_HOME/bin;
  1201 
  1202 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1203 
  1204 * print mode 'emacs' reserved for Isamode;
  1205 
  1206 * support multiple print (ast) translations per constant name;
  1207 
  1208 * theorems involving oracles are now printed with a suffixed [!];
  1209 
  1210 
  1211 *** HOL ***
  1212 
  1213 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1214 
  1215 * HOL/inductive package reorganized and improved: now supports mutual
  1216 definitions such as
  1217 
  1218   inductive EVEN ODD
  1219     intrs
  1220       null "0 : EVEN"
  1221       oddI "n : EVEN ==> Suc n : ODD"
  1222       evenI "n : ODD ==> Suc n : EVEN"
  1223 
  1224 new theorem list "elims" contains an elimination rule for each of the
  1225 recursive sets; inductive definitions now handle disjunctive premises
  1226 correctly (also ZF);
  1227 
  1228 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1229 "mutual_induct" no longer exists - the induction rule is always
  1230 contained in "induct";
  1231 
  1232 
  1233 * HOL/datatype package re-implemented and greatly improved: now
  1234 supports mutually recursive datatypes such as
  1235 
  1236   datatype
  1237     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1238             | SUM ('a aexp) ('a aexp)
  1239             | DIFF ('a aexp) ('a aexp)
  1240             | NUM 'a
  1241   and
  1242     'a bexp = LESS ('a aexp) ('a aexp)
  1243             | AND ('a bexp) ('a bexp)
  1244             | OR ('a bexp) ('a bexp)
  1245 
  1246 as well as indirectly recursive datatypes such as
  1247 
  1248   datatype
  1249     ('a, 'b) term = Var 'a
  1250                   | App 'b ((('a, 'b) term) list)
  1251 
  1252 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1253 induction on mutually / indirectly recursive datatypes.
  1254 
  1255 Primrec equations are now stored in theory and can be accessed via
  1256 <function_name>.simps.
  1257 
  1258 INCOMPATIBILITIES:
  1259 
  1260   - Theories using datatypes must now have theory Datatype as an
  1261     ancestor.
  1262   - The specific <typename>.induct_tac no longer exists - use the
  1263     generic induct_tac instead.
  1264   - natE has been renamed to nat.exhaust - use exhaust_tac
  1265     instead of res_inst_tac ... natE. Note that the variable
  1266     names in nat.exhaust differ from the names in natE, this
  1267     may cause some "fragile" proofs to fail.
  1268   - The theorems split_<typename>_case and split_<typename>_case_asm
  1269     have been renamed to <typename>.split and <typename>.split_asm.
  1270   - Since default sorts of type variables are now handled correctly,
  1271     some datatype definitions may have to be annotated with explicit
  1272     sort constraints.
  1273   - Primrec definitions no longer require function name and type
  1274     of recursive argument.
  1275 
  1276 Consider using isatool fixdatatype to adapt your theories and proof
  1277 scripts to the new package (backup your sources first!).
  1278 
  1279 
  1280 * HOL/record package: considerably improved implementation; now
  1281 includes concrete syntax for record types, terms, updates; theorems
  1282 for surjective pairing and splitting !!-bound record variables; proof
  1283 support is as follows:
  1284 
  1285   1) standard conversions (selectors or updates applied to record
  1286 constructor terms) are part of the standard simpset;
  1287 
  1288   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1289 made part of standard simpset and claset via addIffs;
  1290 
  1291   3) a tactic for record field splitting (record_split_tac) is part of
  1292 the standard claset (addSWrapper);
  1293 
  1294 To get a better idea about these rules you may retrieve them via
  1295 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1296 the name of your record type.
  1297 
  1298 The split tactic 3) conceptually simplifies by the following rule:
  1299 
  1300   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1301 
  1302 Thus any record variable that is bound by meta-all will automatically
  1303 blow up into some record constructor term, consequently the
  1304 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1305 solve record problems automatically.
  1306 
  1307 
  1308 * reorganized the main HOL image: HOL/Integ and String loaded by
  1309 default; theory Main includes everything;
  1310 
  1311 * automatic simplification of integer sums and comparisons, using cancellation;
  1312 
  1313 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1314 
  1315 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1316 
  1317 * many new identities for unions, intersections, set difference, etc.;
  1318 
  1319 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1320 called split_if, split_split, split_sum_case and split_nat_case (to go
  1321 with add/delsplits);
  1322 
  1323 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1324 (?x::unit) = (); this is made part of the default simpset, which COULD
  1325 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1326 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1327 unit_abs_eta_conv is added in order to counter the effect of
  1328 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1329 %u.f();
  1330 
  1331 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1332 makes more sense);
  1333 
  1334 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1335   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1336   disjointness reasoning but breaking a few old proofs.
  1337 
  1338 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1339 to 'converse' from 'inverse' (for compatibility with ZF and some
  1340 literature);
  1341 
  1342 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1343 the well-founded relation;
  1344 
  1345 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1346     Compl A.  The "Compl" syntax remains available as input syntax for this
  1347     release ONLY.
  1348 
  1349 * HOL/Update: new theory of function updates:
  1350     f(a:=b) == %x. if x=a then b else f x
  1351 may also be iterated as in f(a:=b,c:=d,...);
  1352 
  1353 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1354 
  1355 * HOL/List:
  1356   - new function list_update written xs[i:=v] that updates the i-th
  1357     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1358   - new function `upt' written [i..j(] which generates the list
  1359     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1360     bound write [i..j], which is a shorthand for [i..j+1(].
  1361   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1362 
  1363 * HOL/Arith:
  1364   - removed 'pred' (predecessor) function;
  1365   - generalized some theorems about n-1;
  1366   - many new laws about "div" and "mod";
  1367   - new laws about greatest common divisors (see theory ex/Primes);
  1368 
  1369 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1370 instead of "inverse";
  1371 
  1372 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1373   of the multiset ordering;
  1374 
  1375 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1376   (not included by default);
  1377 
  1378 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1379 
  1380 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1381   programs, i.e. different program variables may have different types.
  1382 
  1383 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1384   [previously, this check worked only if the rewrite rule was unconditional]
  1385   Now rew can involve either definitions or equalities (either == or =).
  1386 
  1387 
  1388 *** ZF ***
  1389 
  1390 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1391   only the theorems proved on ZF.ML;
  1392 
  1393 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1394   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1395   disjointness reasoning but breaking a few old proofs.
  1396 
  1397 * ZF/Update: new theory of function updates
  1398     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1399   may also be iterated as in f(a:=b,c:=d,...);
  1400 
  1401 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1402 
  1403 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1404   [previously, this check worked only if the rewrite rule was unconditional]
  1405   Now rew can involve either definitions or equalities (either == or =).
  1406 
  1407 * case_tac provided for compatibility with HOL
  1408     (like the old excluded_middle_tac, but with subgoals swapped)
  1409 
  1410 
  1411 *** Internal programming interfaces ***
  1412 
  1413 * Pure: several new basic modules made available for general use, see
  1414 also src/Pure/README;
  1415 
  1416 * improved the theory data mechanism to support encapsulation (data
  1417 kind name replaced by private Object.kind, acting as authorization
  1418 key); new type-safe user interface via functor TheoryDataFun; generic
  1419 print_data function becomes basically useless;
  1420 
  1421 * removed global_names compatibility flag -- all theory declarations
  1422 are qualified by default;
  1423 
  1424 * module Pure/Syntax now offers quote / antiquote translation
  1425 functions (useful for Hoare logic etc. with implicit dependencies);
  1426 see HOL/ex/Antiquote for an example use;
  1427 
  1428 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1429 cterm -> thm;
  1430 
  1431 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1432 subgoal;
  1433 
  1434 * Display.print_goals function moved to Locale.print_goals;
  1435 
  1436 * standard print function for goals supports current_goals_markers
  1437 variable for marking begin of proof, end of proof, start of goal; the
  1438 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1439 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1440 for example;
  1441 
  1442 
  1443 
  1444 New in Isabelle98 (January 1998)
  1445 --------------------------------
  1446 
  1447 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1448 
  1449 * changed lexical syntax of terms / types: dots made part of long
  1450 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1451 
  1452 * simpset (and claset) reference variable replaced by functions
  1453 simpset / simpset_ref;
  1454 
  1455 * no longer supports theory aliases (via merge) and non-trivial
  1456 implicit merge of thms' signatures;
  1457 
  1458 * most internal names of constants changed due to qualified names;
  1459 
  1460 * changed Pure/Sequence interface (see Pure/seq.ML);
  1461 
  1462 
  1463 *** General Changes ***
  1464 
  1465 * hierachically structured name spaces (for consts, types, axms, thms
  1466 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1467 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1468 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1469 long_names for fully qualified output names; NOTE: ML programs
  1470 (special tactics, packages etc.) referring to internal names may have
  1471 to be adapted to cope with fully qualified names; in case of severe
  1472 backward campatibility problems try setting 'global_names' at compile
  1473 time to have enrything declared within a flat name space; one may also
  1474 fine tune name declarations in theories via the 'global' and 'local'
  1475 section;
  1476 
  1477 * reimplemented the implicit simpset and claset using the new anytype
  1478 data filed in signatures; references simpset:simpset ref etc. are
  1479 replaced by functions simpset:unit->simpset and
  1480 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1481 to patch your ML files accordingly;
  1482 
  1483 * HTML output now includes theory graph data for display with Java
  1484 applet or isatool browser; data generated automatically via isatool
  1485 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1486 
  1487 * defs may now be conditional; improved rewrite_goals_tac to handle
  1488 conditional equations;
  1489 
  1490 * defs now admits additional type arguments, using TYPE('a) syntax;
  1491 
  1492 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1493 creates a new theory node; implicit merge of thms' signatures is
  1494 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1495 transfer:theory->thm->thm in (rare) cases;
  1496 
  1497 * improved handling of draft signatures / theories; draft thms (and
  1498 ctyps, cterms) are automatically promoted to real ones;
  1499 
  1500 * slightly changed interfaces for oracles: admit many per theory, named
  1501 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1502 
  1503 * print_goals: optional output of const types (set show_consts and
  1504 show_types);
  1505 
  1506 * improved output of warnings (###) and errors (***);
  1507 
  1508 * subgoal_tac displays a warning if the new subgoal has type variables;
  1509 
  1510 * removed old README and Makefiles;
  1511 
  1512 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1513 
  1514 * removed obsolete init_pps and init_database;
  1515 
  1516 * deleted the obsolete tactical STATE, which was declared by
  1517     fun STATE tacfun st = tacfun st st;
  1518 
  1519 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1520 (which abbreviates $HOME);
  1521 
  1522 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1523 use isatool fixseq to adapt your ML programs (this works for fully
  1524 qualified references to the Sequence structure only!);
  1525 
  1526 * use_thy no longer requires writable current directory; it always
  1527 reloads .ML *and* .thy file, if either one is out of date;
  1528 
  1529 
  1530 *** Classical Reasoner ***
  1531 
  1532 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1533 tactics that use classical reasoning to simplify a subgoal without
  1534 splitting it into several subgoals;
  1535 
  1536 * Safe_tac: like safe_tac but uses the default claset;
  1537 
  1538 
  1539 *** Simplifier ***
  1540 
  1541 * added simplification meta rules:
  1542     (asm_)(full_)simplify: simpset -> thm -> thm;
  1543 
  1544 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1545 logics (again);
  1546 
  1547 * added prems argument to simplification procedures;
  1548 
  1549 * HOL, FOL, ZF: added infix function `addsplits':
  1550   instead of `<simpset> setloop (split_tac <thms>)'
  1551   you can simply write `<simpset> addsplits <thms>'
  1552 
  1553 
  1554 *** Syntax ***
  1555 
  1556 * TYPE('a) syntax for type reflection terms;
  1557 
  1558 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1559 
  1560 * pretty printer: changed order of mixfix annotation preference (again!);
  1561 
  1562 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1563 
  1564 
  1565 *** HOL ***
  1566 
  1567 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1568   with `addloop' of the simplifier to faciliate case splitting in premises.
  1569 
  1570 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1571 
  1572 * HOL/Auth: new protocol proofs including some for the Internet
  1573   protocol TLS;
  1574 
  1575 * HOL/Map: new theory of `maps' a la VDM;
  1576 
  1577 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1578 cancelling out common nat summands from =, <, <= (in)equalities, or
  1579 differences; simplification procedures nat_cancel_factor for
  1580 cancelling common factor from =, <, <= (in)equalities over natural
  1581 sums; nat_cancel contains both kinds of procedures, it is installed by
  1582 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1583 
  1584 * HOL/simplifier: terms of the form
  1585   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1586   are rewritten to
  1587   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1588   and those of the form
  1589   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1590   are rewritten to
  1591   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1592 
  1593 * HOL/datatype
  1594   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1595 
  1596   P(t_case f1 ... fn x) =
  1597      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1598         ...
  1599        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1600      )
  1601 
  1602   and a theorem `split_t_case_asm' of the form
  1603 
  1604   P(t_case f1 ... fn x) =
  1605     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1606         ...
  1607        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1608      )
  1609   which can be added to a simpset via `addsplits'. The existing theorems
  1610   expand_list_case and expand_option_case have been renamed to
  1611   split_list_case and split_option_case.
  1612 
  1613 * HOL/Arithmetic:
  1614   - `pred n' is automatically converted to `n-1'.
  1615     Users are strongly encouraged not to use `pred' any longer,
  1616     because it will disappear altogether at some point.
  1617   - Users are strongly encouraged to write "0 < n" rather than
  1618     "n ~= 0". Theorems and proof tools have been modified towards this
  1619     `standard'.
  1620 
  1621 * HOL/Lists:
  1622   the function "set_of_list" has been renamed "set" (and its theorems too);
  1623   the function "nth" now takes its arguments in the reverse order and
  1624   has acquired the infix notation "!" as in "xs!n".
  1625 
  1626 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1627 
  1628 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1629   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1630 
  1631 * HOL/record: extensible records with schematic structural subtyping
  1632 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1633 still lacks various theorems and concrete record syntax;
  1634 
  1635 
  1636 *** HOLCF ***
  1637 
  1638 * removed "axioms" and "generated by" sections;
  1639 
  1640 * replaced "ops" section by extended "consts" section, which is capable of
  1641   handling the continuous function space "->" directly;
  1642 
  1643 * domain package:
  1644   . proves theorems immediately and stores them in the theory,
  1645   . creates hierachical name space,
  1646   . now uses normal mixfix annotations (instead of cinfix...),
  1647   . minor changes to some names and values (for consistency),
  1648   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1649   . separator between mutual domain defs: changed "," to "and",
  1650   . improved handling of sort constraints;  now they have to
  1651     appear on the left-hand side of the equations only;
  1652 
  1653 * fixed LAM <x,y,zs>.b syntax;
  1654 
  1655 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1656 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1657 
  1658 
  1659 *** FOL and ZF ***
  1660 
  1661 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1662   with `addloop' of the simplifier to faciliate case splitting in premises.
  1663 
  1664 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1665 in HOL, they strip ALL and --> from proved theorems;
  1666 
  1667 
  1668 
  1669 New in Isabelle94-8 (May 1997)
  1670 ------------------------------
  1671 
  1672 *** General Changes ***
  1673 
  1674 * new utilities to build / run / maintain Isabelle etc. (in parts
  1675 still somewhat experimental); old Makefiles etc. still functional;
  1676 
  1677 * new 'Isabelle System Manual';
  1678 
  1679 * INSTALL text, together with ./configure and ./build scripts;
  1680 
  1681 * reimplemented type inference for greater efficiency, better error
  1682 messages and clean internal interface;
  1683 
  1684 * prlim command for dealing with lots of subgoals (an easier way of
  1685 setting goals_limit);
  1686 
  1687 
  1688 *** Syntax ***
  1689 
  1690 * supports alternative (named) syntax tables (parser and pretty
  1691 printer); internal interface is provided by add_modesyntax(_i);
  1692 
  1693 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1694 be used in conjunction with the Isabelle symbol font; uses the
  1695 "symbols" syntax table;
  1696 
  1697 * added token_translation interface (may translate name tokens in
  1698 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1699 the current print_mode); IMPORTANT: user print translation functions
  1700 are responsible for marking newly introduced bounds
  1701 (Syntax.mark_boundT);
  1702 
  1703 * token translations for modes "xterm" and "xterm_color" that display
  1704 names in bold, underline etc. or colors (which requires a color
  1705 version of xterm);
  1706 
  1707 * infixes may now be declared with names independent of their syntax;
  1708 
  1709 * added typed_print_translation (like print_translation, but may
  1710 access type of constant);
  1711 
  1712 
  1713 *** Classical Reasoner ***
  1714 
  1715 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1716 some limitations.  Blast_tac...
  1717   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1718   + ignores elimination rules that don't have the correct format
  1719         (the conclusion MUST be a formula variable)
  1720   + ignores types, which can make HOL proofs fail
  1721   + rules must not require higher-order unification, e.g. apply_type in ZF
  1722     [message "Function Var's argument not a bound variable" relates to this]
  1723   + its proof strategy is more general but can actually be slower
  1724 
  1725 * substitution with equality assumptions no longer permutes other
  1726 assumptions;
  1727 
  1728 * minor changes in semantics of addafter (now called addaltern); renamed
  1729 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1730 (and access functions for it);
  1731 
  1732 * improved combination of classical reasoner and simplifier:
  1733   + functions for handling clasimpsets
  1734   + improvement of addss: now the simplifier is called _after_ the
  1735     safe steps.
  1736   + safe variant of addss called addSss: uses safe simplifications
  1737     _during_ the safe steps. It is more complete as it allows multiple
  1738     instantiations of unknowns (e.g. with slow_tac).
  1739 
  1740 *** Simplifier ***
  1741 
  1742 * added interface for simplification procedures (functions that
  1743 produce *proven* rewrite rules on the fly, depending on current
  1744 redex);
  1745 
  1746 * ordering on terms as parameter (used for ordered rewriting);
  1747 
  1748 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1749 
  1750 * the solver is now split into a safe and an unsafe part.
  1751 This should be invisible for the normal user, except that the
  1752 functions setsolver and addsolver have been renamed to setSolver and
  1753 addSolver; added safe_asm_full_simp_tac;
  1754 
  1755 
  1756 *** HOL ***
  1757 
  1758 * a generic induction tactic `induct_tac' which works for all datatypes and
  1759 also for type `nat';
  1760 
  1761 * a generic case distinction tactic `exhaust_tac' which works for all
  1762 datatypes and also for type `nat';
  1763 
  1764 * each datatype comes with a function `size';
  1765 
  1766 * patterns in case expressions allow tuple patterns as arguments to
  1767 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1768 
  1769 * primrec now also works with type nat;
  1770 
  1771 * recdef: a new declaration form, allows general recursive functions to be
  1772 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1773 
  1774 * the constant for negation has been renamed from "not" to "Not" to
  1775 harmonize with FOL, ZF, LK, etc.;
  1776 
  1777 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1778 infinite lists;
  1779 
  1780 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1781 
  1782 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1783 problems in commutative rings, using axiomatic type classes for + and *;
  1784 
  1785 * more examples in HOL/MiniML and HOL/Auth;
  1786 
  1787 * more default rewrite rules for quantifiers, union/intersection;
  1788 
  1789 * a new constant `arbitrary == @x.False';
  1790 
  1791 * HOLCF/IOA replaces old HOL/IOA;
  1792 
  1793 * HOLCF changes: derived all rules and arities
  1794   + axiomatic type classes instead of classes
  1795   + typedef instead of faking type definitions
  1796   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1797   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1798   + eliminated the types void, one, tr
  1799   + use unit lift and bool lift (with translations) instead of one and tr
  1800   + eliminated blift from Lift3.thy (use Def instead of blift)
  1801   all eliminated rules are derived as theorems --> no visible changes ;
  1802 
  1803 
  1804 *** ZF ***
  1805 
  1806 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1807 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1808 as ZF_cs addSIs [equalityI];
  1809 
  1810 
  1811 
  1812 New in Isabelle94-7 (November 96)
  1813 ---------------------------------
  1814 
  1815 * allowing negative levels (as offsets) in prlev and choplev;
  1816 
  1817 * super-linear speedup for large simplifications;
  1818 
  1819 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1820 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1821 FAIL); can suppress it using the command Delsimps (ex_simps @
  1822 all_simps); De Morgan laws are also now included, by default;
  1823 
  1824 * improved printing of ==>  :  ~:
  1825 
  1826 * new object-logic "Sequents" adds linear logic, while replacing LK
  1827 and Modal (thanks to Sara Kalvala);
  1828 
  1829 * HOL/Auth: correctness proofs for authentication protocols;
  1830 
  1831 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1832 examples on HOL/Auth);
  1833 
  1834 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1835 the rewriter and classical reasoner simultaneously;
  1836 
  1837 * function uresult no longer returns theorems in "standard" format;
  1838 regain previous version by: val uresult = standard o uresult;
  1839 
  1840 
  1841 
  1842 New in Isabelle94-6
  1843 -------------------
  1844 
  1845 * oracles -- these establish an interface between Isabelle and trusted
  1846 external reasoners, which may deliver results as theorems;
  1847 
  1848 * proof objects (in particular record all uses of oracles);
  1849 
  1850 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1851 
  1852 * "constdefs" section in theory files;
  1853 
  1854 * "primrec" section (HOL) no longer requires names;
  1855 
  1856 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1857 
  1858 
  1859 
  1860 New in Isabelle94-5
  1861 -------------------
  1862 
  1863 * reduced space requirements;
  1864 
  1865 * automatic HTML generation from theories;
  1866 
  1867 * theory files no longer require "..." (quotes) around most types;
  1868 
  1869 * new examples, including two proofs of the Church-Rosser theorem;
  1870 
  1871 * non-curried (1994) version of HOL is no longer distributed;
  1872 
  1873 
  1874 
  1875 New in Isabelle94-4
  1876 -------------------
  1877 
  1878 * greatly reduced space requirements;
  1879 
  1880 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1881 
  1882 * searchable theorem database (see the section "Retrieving theorems" on
  1883 page 8 of the Reference Manual);
  1884 
  1885 * new examples, including Grabczewski's monumental case study of the
  1886 Axiom of Choice;
  1887 
  1888 * The previous version of HOL renamed to Old_HOL;
  1889 
  1890 * The new version of HOL (previously called CHOL) uses a curried syntax
  1891 for functions.  Application looks like f a b instead of f(a,b);
  1892 
  1893 * Mutually recursive inductive definitions finally work in HOL;
  1894 
  1895 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1896 translates to the operator "split";
  1897 
  1898 
  1899 
  1900 New in Isabelle94-3
  1901 -------------------
  1902 
  1903 * new infix operator, addss, allowing the classical reasoner to
  1904 perform simplification at each step of its search.  Example:
  1905         fast_tac (cs addss ss)
  1906 
  1907 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1908 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1909 look like (a,b) instead of <a,b>;
  1910 
  1911 * PLEASE NOTE: CHOL will eventually replace HOL!
  1912 
  1913 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1914 It translates to the operator "split".  A new theory of integers is available;
  1915 
  1916 * In ZF, integer numerals now denote two's-complement binary integers.
  1917 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1918 
  1919 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1920 of the Axiom of Choice;
  1921 
  1922 
  1923 
  1924 New in Isabelle94-2
  1925 -------------------
  1926 
  1927 * Significantly faster resolution;
  1928 
  1929 * the different sections in a .thy file can now be mixed and repeated
  1930 freely;
  1931 
  1932 * Database of theorems for FOL, HOL and ZF.  New
  1933 commands including qed, qed_goal and bind_thm store theorems in the database.
  1934 
  1935 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1936 a given theory (thms_of), or find out what theory a theorem was proved in
  1937 (theory_of_thm);
  1938 
  1939 * Bugs fixed in the inductive definition and datatype packages;
  1940 
  1941 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1942 and HOL_dup_cs obsolete;
  1943 
  1944 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1945 have been removed;
  1946 
  1947 * Simpler definition of function space in ZF;
  1948 
  1949 * new results about cardinal and ordinal arithmetic in ZF;
  1950 
  1951 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1952 types;
  1953 
  1954 
  1955 $Id$