NEWS
author wenzelm
Sun Oct 14 22:05:01 2001 +0200 (2001-10-14)
changeset 11767 7380c9d45626
parent 11745 06cd8c3b5487
child 11788 60054fee3c16
permissions -rw-r--r--
tuned rewrite/simplify interface;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * support bold style (for single symbols only), input syntax is like
    11 this: "\<^bold>\<alpha>" or "\<^bold>A";
    12 
    13 * \<bullet> is no output as bold \cdot by default, which looks much
    14 better in printed text;
    15 
    16 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    17 note that these symbols are currently unavailable in Proof General /
    18 X-Symbol;
    19 
    20 
    21 *** Isar ***
    22 
    23 * improved proof by cases and induction:
    24   - moved induct/cases attributes to Pure;
    25   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    26   - generic setup instantiated for FOL and HOL;
    27   - removed obsolete "(simplified)" and "(stripped)" options;
    28 
    29 * Pure: renamed "antecedent" case to "rule_context";
    30 
    31 * Pure: added 'corollary' command;
    32 
    33 * Pure: fixed 'token_translation' command;
    34 
    35 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    36 
    37 * HOL: 'recdef' now fails on unfinished automated proofs, use
    38 "(permissive)" option to recover old behavior;
    39 
    40 * HOL: 'inductive' now longer features separate (collective)
    41 attributes for 'intros';
    42 
    43 
    44 *** HOL ***
    45 
    46 * HOL: moved over to sane numeral syntax; the new policy is as
    47 follows:
    48 
    49   - 0 and 1 are polymorphic constants, which are defined on any
    50   numeric type (nat, int, real etc.);
    51 
    52   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    53   binary representation internally;
    54 
    55   - type nat has special constructor Suc, and generally prefers Suc 0
    56   over 1::nat and Suc (Suc 0) over 2::nat;
    57 
    58 This change may cause significant INCOMPATIBILITIES; here are some
    59 hints on converting existing sources:
    60 
    61   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    62   entities, so expressions involving "-" (unary or binary minus) need
    63   to be spaced properly;
    64 
    65   - existing occurrences of "1" may need to be constraint "1::nat" or
    66   even replaced by Suc 0; similar for old "2";
    67 
    68   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
    69 
    70   - remove all special provisions on numerals in proofs;
    71 
    72 * HOL: linorder_less_split superseded by linorder_cases;
    73 
    74 * HOL: added "The" definite description operator; move Hilbert's "Eps"
    75 to peripheral theory "Hilbert_Choice";
    76 
    77 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
    78 in this (rare) case use:
    79 
    80   delSWrapper "split_all_tac"
    81   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
    82 
    83 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
    84 MAY FAIL;
    85 
    86 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
    87 Isabelle's type classes, ^ on functions and relations has too general
    88 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
    89 necessary to attach explicit type constraints;
    90 
    91 * HOL: syntax translations now work properly with numerals and records
    92 expressions;
    93 
    94 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
    95 Florian Kammüller;
    96 
    97 * HOL: eliminated global items
    98 
    99   const "()" -> "Product_Type.Unity"
   100   type "unit" -> "Product_Type.unit"
   101 
   102 
   103 *** ZF ***
   104 
   105 * ZF: the integer library now covers quotients and remainders, with
   106 many laws relating division to addition, multiplication, etc.;
   107 
   108 
   109 *** General ***
   110 
   111 * Meta-level proof terms (by Stefan Berghofer), see also ref manual;
   112 
   113 * new token syntax "num" for plain numerals (without "#" of "xnum");
   114 potential INCOMPATIBILITY, since -0, -1 etc. are now separate tokens,
   115 so expressions involving minus need to be spaced properly;
   116 
   117 * Classical reasoner: renamed addaltern to addafter, addSaltern to
   118 addSafter;
   119 
   120 * syntax: support non-oriented infixes;
   121 
   122 * print modes "type_brackets" and "no_type_brackets" control output of
   123 nested => (types); the default behavior is "brackets";
   124 
   125 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   126 
   127 * system: Proof General keywords specification is now part of the
   128 Isabelle distribution (see etc/isar-keywords.el);
   129 
   130 * system: smart selection of Isabelle process versus Isabelle
   131 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   132 run both "isabelle" and "Isabelle" even if file names are badly
   133 damaged (executable inspects the case of the first letter of its own
   134 name); added separate "isabelle-process" and "isabelle-interface";
   135 
   136 
   137 
   138 New in Isabelle99-2 (February 2001)
   139 -----------------------------------
   140 
   141 *** Overview of INCOMPATIBILITIES ***
   142 
   143 * HOL: please note that theories in the Library and elsewhere often use the
   144 new-style (Isar) format; to refer to their theorems in an ML script you must
   145 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   146 
   147 * HOL: inductive package no longer splits induction rule aggressively,
   148 but only as far as specified by the introductions given; the old
   149 format may be recovered via ML function complete_split_rule or attribute
   150 'split_rule (complete)';
   151 
   152 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   153 gfp_Tarski to gfp_unfold;
   154 
   155 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   156 
   157 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   158 relation); infix "^^" has been renamed "``"; infix "``" has been
   159 renamed "`"; "univalent" has been renamed "single_valued";
   160 
   161 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   162 operation;
   163 
   164 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   165 
   166 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   167 
   168 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   169 consequence, it is no longer monotonic wrt. the local goal context
   170 (which is now passed through the inductive cases);
   171 
   172 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   173 \<gg> to \<ggreater>;
   174 
   175 
   176 *** Document preparation ***
   177 
   178 * \isabellestyle{NAME} selects version of Isabelle output (currently
   179 available: are "it" for near math-mode best-style output, "sl" for
   180 slanted text style, and "tt" for plain type-writer; if no
   181 \isabellestyle command is given, output is according to slanted
   182 type-writer);
   183 
   184 * support sub/super scripts (for single symbols only), input syntax is
   185 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   186 
   187 * some more standard symbols; see Appendix A of the system manual for
   188 the complete list of symbols defined in isabellesym.sty;
   189 
   190 * improved isabelle style files; more abstract symbol implementation
   191 (should now use \isamath{...} and \isatext{...} in custom symbol
   192 definitions);
   193 
   194 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   195 state; Note that presentation of goal states does not conform to
   196 actual human-readable proof documents.  Please do not include goal
   197 states into document output unless you really know what you are doing!
   198 
   199 * proper indentation of antiquoted output with proportional LaTeX
   200 fonts;
   201 
   202 * no_document ML operator temporarily disables LaTeX document
   203 generation;
   204 
   205 * isatool unsymbolize tunes sources for plain ASCII communication;
   206 
   207 
   208 *** Isar ***
   209 
   210 * Pure: Isar now suffers initial goal statements to contain unbound
   211 schematic variables (this does not conform to actual readable proof
   212 documents, due to unpredictable outcome and non-compositional proof
   213 checking); users who know what they are doing may use schematic goals
   214 for Prolog-style synthesis of proven results;
   215 
   216 * Pure: assumption method (an implicit finishing) now handles actual
   217 rules as well;
   218 
   219 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   220 initial goal, declare "that" only as Pure intro (only for single
   221 steps); the "that" rule assumption may now be involved in implicit
   222 finishing, thus ".." becomes a feasible for trivial obtains;
   223 
   224 * Pure: default proof step now includes 'intro_classes'; thus trivial
   225 instance proofs may be performed by "..";
   226 
   227 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   228 statements as well;
   229 
   230 * Pure: more robust selection of calculational rules;
   231 
   232 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   233 rule (as well as the assumption rule);
   234 
   235 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   236 lemmas, using the graph browser tool;
   237 
   238 * Pure: predict failure of "show" in interactive mode;
   239 
   240 * Pure: 'thms_containing' now takes actual terms as arguments;
   241 
   242 * HOL: improved method 'induct' --- now handles non-atomic goals
   243 (potential INCOMPATIBILITY); tuned error handling;
   244 
   245 * HOL: cases and induct rules now provide explicit hints about the
   246 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   247 any remaining facts are inserted into the goal verbatim;
   248 
   249 * HOL: local contexts (aka cases) may now contain term bindings as
   250 well; the 'cases' and 'induct' methods new provide a ?case binding for
   251 the result to be shown in each case;
   252 
   253 * HOL: added 'recdef_tc' command;
   254 
   255 * isatool convert assists in eliminating legacy ML scripts;
   256 
   257 
   258 *** HOL ***
   259 
   260 * HOL/Library: a collection of generic theories to be used together
   261 with main HOL; the theory loader path already includes this directory
   262 by default; the following existing theories have been moved here:
   263 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   264 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   265 
   266 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   267 modelling and verification task performed in Isabelle/HOL +
   268 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   269 
   270 * HOL/Algebra: special summation operator SUM no longer exists, it has
   271 been replaced by setsum; infix 'assoc' now has priority 50 (like
   272 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   273 'domain', this makes the theory consistent with mathematical
   274 literature;
   275 
   276 * HOL basics: added overloaded operations "inverse" and "divide"
   277 (infix "/"), syntax for generic "abs" operation, generic summation
   278 operator \<Sum>;
   279 
   280 * HOL/typedef: simplified package, provide more useful rules (see also
   281 HOL/subset.thy);
   282 
   283 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   284 now expressed as a proper nested rule (old-style tactic scripts may
   285 require atomize_strip_tac to cope with non-atomic premises);
   286 
   287 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   288 to "split_conv" (old name still available for compatibility);
   289 
   290 * HOL: improved concrete syntax for strings (e.g. allows translation
   291 rules with string literals);
   292 
   293 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   294 and Fleuriot's mechanization of analysis;
   295 
   296 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   297 
   298 
   299 *** CTT ***
   300 
   301 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   302 "lam" is displayed as TWO lambda-symbols
   303 
   304 * CTT: theory Main now available, containing everything (that is, Bool
   305 and Arith);
   306 
   307 
   308 *** General ***
   309 
   310 * Pure: the Simplifier has been implemented properly as a derived rule
   311 outside of the actual kernel (at last!); the overall performance
   312 penalty in practical applications is about 50%, while reliability of
   313 the Isabelle inference kernel has been greatly improved;
   314 
   315 * print modes "brackets" and "no_brackets" control output of nested =>
   316 (types) and ==> (props); the default behaviour is "brackets";
   317 
   318 * Provers: fast_tac (and friends) now handle actual object-logic rules
   319 as assumptions as well;
   320 
   321 * system: support Poly/ML 4.0;
   322 
   323 * system: isatool install handles KDE version 1 or 2;
   324 
   325 
   326 
   327 New in Isabelle99-1 (October 2000)
   328 ----------------------------------
   329 
   330 *** Overview of INCOMPATIBILITIES ***
   331 
   332 * HOL: simplification of natural numbers is much changed; to partly
   333 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   334 issue the following ML commands:
   335 
   336   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   337   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   338 
   339 * HOL: simplification no longer dives into case-expressions; this is
   340 controlled by "t.weak_case_cong" for each datatype t;
   341 
   342 * HOL: nat_less_induct renamed to less_induct;
   343 
   344 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   345 fixsome to patch .thy and .ML sources automatically;
   346 
   347   select_equality  -> some_equality
   348   select_eq_Ex     -> some_eq_ex
   349   selectI2EX       -> someI2_ex
   350   selectI2         -> someI2
   351   selectI          -> someI
   352   select1_equality -> some1_equality
   353   Eps_sym_eq       -> some_sym_eq_trivial
   354   Eps_eq           -> some_eq_trivial
   355 
   356 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   357 
   358 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   359 instead);
   360 
   361 * HOL: the recursion equations generated by 'recdef' are now called
   362 f.simps instead of f.rules;
   363 
   364 * HOL: qed_spec_mp now also handles bounded ALL as well;
   365 
   366 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   367 sometimes be needed;
   368 
   369 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   370 
   371 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   372 
   373 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   374 product is now "<*>" instead of "Times"; the lexicographic product is
   375 now "<*lex*>" instead of "**";
   376 
   377 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   378 of main HOL, but was unused); better use HOL's datatype package;
   379 
   380 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   381 the old syntax may be recovered as follows:
   382 
   383   syntax (symbols)
   384     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   385       (infixl "\\<oplus>" 100)
   386 
   387 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   388 
   389 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   390 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   391 internally;
   392 
   393 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   394 changed from A/r to A//r;
   395 
   396 * ZF: new treatment of arithmetic (nat & int) may break some old
   397 proofs;
   398 
   399 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   400 rulify -> rule_format, elimify -> elim_format, ...);
   401 
   402 * Isar/Provers: intro/elim/dest attributes changed; renamed
   403 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   404 should have to change intro!! to intro? only); replaced "delrule" by
   405 "rule del";
   406 
   407 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   408 
   409 * Provers: strengthened force_tac by using new first_best_tac;
   410 
   411 * LaTeX document preparation: several changes of isabelle.sty (see
   412 lib/texinputs);
   413 
   414 
   415 *** Document preparation ***
   416 
   417 * formal comments (text blocks etc.) in new-style theories may now
   418 contain antiquotations of thm/prop/term/typ/text to be presented
   419 according to latex print mode; concrete syntax is like this:
   420 @{term[show_types] "f(x) = a + x"};
   421 
   422 * isatool mkdir provides easy setup of Isabelle session directories,
   423 including proper document sources;
   424 
   425 * generated LaTeX sources are now deleted after successful run
   426 (isatool document -c); may retain a copy somewhere else via -D option
   427 of isatool usedir;
   428 
   429 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   430 style files, achieving self-contained LaTeX sources and simplifying
   431 LaTeX debugging;
   432 
   433 * old-style theories now produce (crude) LaTeX output as well;
   434 
   435 * browser info session directories are now self-contained (may be put
   436 on WWW server seperately); improved graphs of nested sessions; removed
   437 graph for 'all sessions';
   438 
   439 * several improvements in isabelle style files; \isabellestyle{it}
   440 produces fake math mode output; \isamarkupheader is now \section by
   441 default; see lib/texinputs/isabelle.sty etc.;
   442 
   443 
   444 *** Isar ***
   445 
   446 * Isar/Pure: local results and corresponding term bindings are now
   447 subject to Hindley-Milner polymorphism (similar to ML); this
   448 accommodates incremental type-inference very nicely;
   449 
   450 * Isar/Pure: new derived language element 'obtain' supports
   451 generalized existence reasoning;
   452 
   453 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   454 support accumulation of results, without applying any rules yet;
   455 useful to collect intermediate results without explicit name
   456 references, and for use with transitivity rules with more than 2
   457 premises;
   458 
   459 * Isar/Pure: scalable support for case-analysis type proofs: new
   460 'case' language element refers to local contexts symbolically, as
   461 produced by certain proof methods; internally, case names are attached
   462 to theorems as "tags";
   463 
   464 * Isar/Pure: theory command 'hide' removes declarations from
   465 class/type/const name spaces;
   466 
   467 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   468 indicate potential overloading;
   469 
   470 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   471 
   472 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   473 "{a,b,c}" instead of {a,b,c};
   474 
   475 * Isar/Pure now provides its own version of intro/elim/dest
   476 attributes; useful for building new logics, but beware of confusion
   477 with the version in Provers/classical;
   478 
   479 * Isar/Pure: the local context of (non-atomic) goals is provided via
   480 case name 'antecedent';
   481 
   482 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   483 to the current context is now done automatically);
   484 
   485 * Isar/Pure: theory command 'method_setup' provides a simple interface
   486 for definining proof methods in ML;
   487 
   488 * Isar/Provers: intro/elim/dest attributes changed; renamed
   489 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   490 most cases, one should have to change intro!! to intro? only);
   491 replaced "delrule" by "rule del";
   492 
   493 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   494 'symmetric' attribute (the latter supercedes [RS sym]);
   495 
   496 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   497 method modifier); 'simp' method: 'only:' modifier removes loopers as
   498 well (including splits);
   499 
   500 * Isar/Provers: Simplifier and Classical methods now support all kind
   501 of modifiers used in the past, including 'cong', 'iff', etc.
   502 
   503 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   504 of Simplifier and Classical reasoner);
   505 
   506 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   507 now support named cases; major packages (inductive, datatype, primrec,
   508 recdef) support case names and properly name parameters;
   509 
   510 * Isar/HOL: new transitivity rules for substitution in inequalities --
   511 monotonicity conditions are extracted to be proven at end of
   512 calculations;
   513 
   514 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   515 method anyway;
   516 
   517 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   518 split_if split_if_asm; datatype package provides theorems foo.splits =
   519 foo.split foo.split_asm for each datatype;
   520 
   521 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   522 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   523 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   524 use "(cases (simplified))" method in proper proof texts);
   525 
   526 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   527 
   528 * Isar: names of theorems etc. may be natural numbers as well;
   529 
   530 * Isar: 'pr' command: optional arguments for goals_limit and
   531 ProofContext.prems_limit; no longer prints theory contexts, but only
   532 proof states;
   533 
   534 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   535 additional print modes to be specified; e.g. "pr(latex)" will print
   536 proof state according to the Isabelle LaTeX style;
   537 
   538 * Isar: improved support for emulating tactic scripts, including proof
   539 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   540 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   541 (for HOL datatypes);
   542 
   543 * Isar: simplified (more robust) goal selection of proof methods: 1st
   544 goal, all goals, or explicit goal specifier (tactic emulation); thus
   545 'proof method scripts' have to be in depth-first order;
   546 
   547 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   548 
   549 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   550 should instead use individual commands for printing items
   551 (print_commands, print_methods etc.);
   552 
   553 * Isar: added 'nothing' --- the empty list of theorems;
   554 
   555 
   556 *** HOL ***
   557 
   558 * HOL/MicroJava: formalization of a fragment of Java, together with a
   559 corresponding virtual machine and a specification of its bytecode
   560 verifier and a lightweight bytecode verifier, including proofs of
   561 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   562 Cornelia Pusch (see also the homepage of project Bali at
   563 http://isabelle.in.tum.de/Bali/);
   564 
   565 * HOL/Algebra: new theory of rings and univariate polynomials, by
   566 Clemens Ballarin;
   567 
   568 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   569 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   570 Rasmussen;
   571 
   572 * HOL/Lattice: fundamental concepts of lattice theory and order
   573 structures, including duals, properties of bounds versus algebraic
   574 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   575 Theorem for complete lattices etc.; may also serve as a demonstration
   576 for abstract algebraic reasoning using axiomatic type classes, and
   577 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   578 
   579 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   580 von Oheimb;
   581 
   582 * HOL/IMPP: extension of IMP with local variables and mutually
   583 recursive procedures, by David von Oheimb;
   584 
   585 * HOL/Lambda: converted into new-style theory and document;
   586 
   587 * HOL/ex/Multiquote: example of multiple nested quotations and
   588 anti-quotations -- basically a generalized version of de-Bruijn
   589 representation; very useful in avoiding lifting of operations;
   590 
   591 * HOL/record: added general record equality rule to simpset; fixed
   592 select-update simplification procedure to handle extended records as
   593 well; admit "r" as field name;
   594 
   595 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   596 other numeric types and also as the identity of groups, rings, etc.;
   597 
   598 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   599 Types nat and int belong to this axclass;
   600 
   601 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   602    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   603    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   604   two terms #m*u and #n*u are replaced by #(m+n)*u
   605     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   606   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   607     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   608 
   609 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   610 powerful prover for predicate logic but knows nothing of clasets; see
   611 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   612 
   613 * HOL: new version of "case_tac" subsumes both boolean case split and
   614 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   615 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   616 
   617 * HOL: simplification no longer dives into case-expressions: only the
   618 selector expression is simplified, but not the remaining arms; to
   619 enable full simplification of case-expressions for datatype t, you may
   620 remove t.weak_case_cong from the simpset, either globally (Delcongs
   621 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   622 
   623 * HOL/recdef: the recursion equations generated by 'recdef' for
   624 function 'f' are now called f.simps instead of f.rules; if all
   625 termination conditions are proved automatically, these simplification
   626 rules are added to the simpset, as in primrec; rules may be named
   627 individually as well, resulting in a separate list of theorems for
   628 each equation;
   629 
   630 * HOL/While is a new theory that provides a while-combinator. It
   631 permits the definition of tail-recursive functions without the
   632 provision of a termination measure. The latter is necessary once the
   633 invariant proof rule for while is applied.
   634 
   635 * HOL: new (overloaded) notation for the set of elements below/above
   636 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   637 
   638 * HOL: theorems impI, allI, ballI bound as "strip";
   639 
   640 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   641 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   642 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   643 
   644 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   645 
   646 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   647 main HOL, but was unused);
   648 
   649 * HOL: fewer consts declared as global (e.g. have to refer to
   650 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   651 
   652 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   653 in case of overlap with user translations (e.g. judgements over
   654 tuples); (note that the underlying logical represenation is still
   655 bogus);
   656 
   657 
   658 *** ZF ***
   659 
   660 * ZF: simplification automatically cancels common terms in arithmetic
   661 expressions over nat and int;
   662 
   663 * ZF: new treatment of nat to minimize type-checking: all operators
   664 coerce their operands to a natural number using the function natify,
   665 making the algebraic laws unconditional;
   666 
   667 * ZF: as above, for int: operators coerce their operands to an integer
   668 using the function intify;
   669 
   670 * ZF: the integer library now contains many of the usual laws for the
   671 orderings, including $<=, and monotonicity laws for $+ and $*;
   672 
   673 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   674 simplification;
   675 
   676 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   677 to the simplifier and classical reasoner simultaneously;
   678 
   679 
   680 *** General ***
   681 
   682 * Provers: blast_tac now handles actual object-logic rules as
   683 assumptions; note that auto_tac uses blast_tac internally as well;
   684 
   685 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   686 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   687 
   688 * Provers: delrules now handles destruct rules as well (no longer need
   689 explicit make_elim);
   690 
   691 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   692   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   693 use instead the strong form,
   694   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   695 in HOL, FOL and ZF the function cla_make_elim will create such rules
   696 from destruct-rules;
   697 
   698 * Provers: Simplifier.easy_setup provides a fast path to basic
   699 Simplifier setup for new object-logics;
   700 
   701 * Pure: AST translation rules no longer require constant head on LHS;
   702 
   703 * Pure: improved name spaces: ambiguous output is qualified; support
   704 for hiding of names;
   705 
   706 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   707 XSYMBOL_HOME; no longer need to do manual configuration in most
   708 situations;
   709 
   710 * system: compression of ML heaps images may now be controlled via -c
   711 option of isabelle and isatool usedir (currently only observed by
   712 Poly/ML);
   713 
   714 * system: isatool installfonts may handle X-Symbol fonts as well (very
   715 useful for remote X11);
   716 
   717 * system: provide TAGS file for Isabelle sources;
   718 
   719 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   720 order;
   721 
   722 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   723 timing flag supersedes proof_timing and Toplevel.trace;
   724 
   725 * ML: new combinators |>> and |>>> for incremental transformations
   726 with secondary results (e.g. certain theory extensions):
   727 
   728 * ML: PureThy.add_defs gets additional argument to indicate potential
   729 overloading (usually false);
   730 
   731 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   732 results;
   733 
   734 
   735 
   736 New in Isabelle99 (October 1999)
   737 --------------------------------
   738 
   739 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   740 
   741 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   742 are no longer simplified.  (This allows the simplifier to unfold recursive
   743 functional programs.)  To restore the old behaviour, declare
   744 
   745     Delcongs [if_weak_cong];
   746 
   747 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   748 complement;
   749 
   750 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   751 
   752 * HOL/datatype: mutual_induct_tac no longer exists --
   753   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   754 
   755 * HOL/typedef: fixed type inference for representing set; type
   756 arguments now have to occur explicitly on the rhs as type constraints;
   757 
   758 * ZF: The con_defs part of an inductive definition may no longer refer
   759 to constants declared in the same theory;
   760 
   761 * HOL, ZF: the function mk_cases, generated by the inductive
   762 definition package, has lost an argument.  To simplify its result, it
   763 uses the default simpset instead of a supplied list of theorems.
   764 
   765 * HOL/List: the constructors of type list are now Nil and Cons;
   766 
   767 * Simplifier: the type of the infix ML functions
   768         setSSolver addSSolver setSolver addSolver
   769 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   770 for packaging solvers. A solver is created via
   771         mk_solver: string -> (thm list -> int -> tactic) -> solver
   772 where the string argument is only a comment.
   773 
   774 
   775 *** Proof tools ***
   776 
   777 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   778 decision procedure for linear arithmetic. Currently it is used for
   779 types `nat', `int', and `real' in HOL (see below); it can, should and
   780 will be instantiated for other types and logics as well.
   781 
   782 * The simplifier now accepts rewrite rules with flexible heads, eg
   783      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   784   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   785   matching.
   786 
   787 
   788 *** General ***
   789 
   790 * New Isabelle/Isar subsystem provides an alternative to traditional
   791 tactical theorem proving; together with the ProofGeneral/isar user
   792 interface it offers an interactive environment for developing human
   793 readable proof documents (Isar == Intelligible semi-automated
   794 reasoning); for further information see isatool doc isar-ref,
   795 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   796 
   797 * improved and simplified presentation of theories: better HTML markup
   798 (including colors), graph views in several sizes; isatool usedir now
   799 provides a proper interface for user theories (via -P option); actual
   800 document preparation based on (PDF)LaTeX is available as well (for
   801 new-style theories only); see isatool doc system for more information;
   802 
   803 * native support for Proof General, both for classic Isabelle and
   804 Isabelle/Isar;
   805 
   806 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   807 using the graph browser tool;
   808 
   809 * Isabelle manuals now also available as PDF;
   810 
   811 * theory loader rewritten from scratch (may not be fully
   812 bug-compatible); old loadpath variable has been replaced by show_path,
   813 add_path, del_path, reset_path functions; new operations such as
   814 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   815 isatool doc ref);
   816 
   817 * improved isatool install: option -k creates KDE application icon,
   818 option -p DIR installs standalone binaries;
   819 
   820 * added ML_PLATFORM setting (useful for cross-platform installations);
   821 more robust handling of platform specific ML images for SML/NJ;
   822 
   823 * the settings environment is now statically scoped, i.e. it is never
   824 created again in sub-processes invoked from isabelle, isatool, or
   825 Isabelle;
   826 
   827 * path element specification '~~' refers to '$ISABELLE_HOME';
   828 
   829 * in locales, the "assumes" and "defines" parts may be omitted if
   830 empty;
   831 
   832 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   833 long arrows);
   834 
   835 * new print_mode "HTML";
   836 
   837 * new flag show_tags controls display of tags of theorems (which are
   838 basically just comments that may be attached by some tools);
   839 
   840 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   841 mode and goal output format:
   842 
   843 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   844 244c244
   845 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   846 ---
   847 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   848 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   849 181c181
   850 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   851 ---
   852 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   853 
   854 * function bind_thms stores lists of theorems (cf. bind_thm);
   855 
   856 * new shorthand tactics ftac, eatac, datac, fatac;
   857 
   858 * qed (and friends) now accept "" as result name; in that case the
   859 theorem is not stored, but proper checks and presentation of the
   860 result still apply;
   861 
   862 * theorem database now also indexes constants "Trueprop", "all",
   863 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   864 
   865 
   866 *** HOL ***
   867 
   868 ** HOL arithmetic **
   869 
   870 * There are now decision procedures for linear arithmetic over nat and
   871 int:
   872 
   873 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   874 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   875 are treated as atomic; subformulae not involving type `nat' or `int'
   876 are ignored; quantified subformulae are ignored unless they are
   877 positive universal or negative existential. The tactic has to be
   878 invoked by hand and can be a little bit slow. In particular, the
   879 running time is exponential in the number of occurrences of `min' and
   880 `max', and `-' on `nat'.
   881 
   882 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   883 (negated) (in)equalities among the premises and the conclusion into
   884 account (i.e. no compound formulae) and does not know about `min' and
   885 `max', and `-' on `nat'. It is fast and is used automatically by the
   886 simplifier.
   887 
   888 NB: At the moment, these decision procedures do not cope with mixed
   889 nat/int formulae where the two parts interact, such as `m < n ==>
   890 int(m) < int(n)'.
   891 
   892 * HOL/Numeral provides a generic theory of numerals (encoded
   893 efficiently as bit strings); setup for types nat/int/real is in place;
   894 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   895 int, existing theories and proof scripts may require a few additional
   896 type constraints;
   897 
   898 * integer division and remainder can now be performed on constant
   899 arguments;
   900 
   901 * many properties of integer multiplication, division and remainder
   902 are now available;
   903 
   904 * An interface to the Stanford Validity Checker (SVC) is available through the
   905 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   906 are proved automatically.  SVC must be installed separately, and its results
   907 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   908 invocation of the underlying oracle).  For SVC see
   909   http://verify.stanford.edu/SVC
   910 
   911 * IsaMakefile: the HOL-Real target now builds an actual image;
   912 
   913 
   914 ** HOL misc **
   915 
   916 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   917 (in Isabelle/Isar) -- by Gertrud Bauer;
   918 
   919 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   920 analysis for assembly languages with subtypes;
   921 
   922 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   923 -- avoids syntactic ambiguities and treats state, transition, and
   924 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   925 changed syntax and (many) tactics;
   926 
   927 * HOL/inductive: Now also handles more general introduction rules such
   928   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   929   theorems are now maintained within the theory (maintained via the
   930   "mono" attribute);
   931 
   932 * HOL/datatype: Now also handles arbitrarily branching datatypes
   933   (using function types) such as
   934 
   935   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   936 
   937 * HOL/record: record_simproc (part of the default simpset) takes care
   938 of selectors applied to updated records; record_split_tac is no longer
   939 part of the default claset; update_defs may now be removed from the
   940 simpset in many cases; COMPATIBILITY: old behavior achieved by
   941 
   942   claset_ref () := claset() addSWrapper record_split_wrapper;
   943   Delsimprocs [record_simproc]
   944 
   945 * HOL/typedef: fixed type inference for representing set; type
   946 arguments now have to occur explicitly on the rhs as type constraints;
   947 
   948 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   949 names rather than an ML expression;
   950 
   951 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   952 supplied later.  Program schemes can be defined, such as
   953     "While B C s = (if B s then While B C (C s) else s)"
   954 where the well-founded relation can be chosen after B and C have been given.
   955 
   956 * HOL/List: the constructors of type list are now Nil and Cons;
   957 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   958 course, ML tools referring to List.list.op # etc. have to be adapted;
   959 
   960 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   961 disabled by default; run isabelle with option -m HOL to get back to
   962 the original Gordon/HOL-style output;
   963 
   964 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   965 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   966 
   967 * HOL basic syntax simplified (more orthogonal): all variants of
   968 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   969 Eps operator is provided as well: "SOME x. P[x]";
   970 
   971 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   972 
   973 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   974 thus available for user theories;
   975 
   976 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   977 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   978 time;
   979 
   980 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   981 several times and then mp;
   982 
   983 
   984 *** LK ***
   985 
   986 * the notation <<...>> is now available as a notation for sequences of
   987 formulas;
   988 
   989 * the simplifier is now installed
   990 
   991 * the axiom system has been generalized (thanks to Soren Heilmann)
   992 
   993 * the classical reasoner now has a default rule database
   994 
   995 
   996 *** ZF ***
   997 
   998 * new primrec section allows primitive recursive functions to be given
   999 directly (as in HOL) over datatypes and the natural numbers;
  1000 
  1001 * new tactics induct_tac and exhaust_tac for induction (or case
  1002 analysis) over datatypes and the natural numbers;
  1003 
  1004 * the datatype declaration of type T now defines the recursor T_rec;
  1005 
  1006 * simplification automatically does freeness reasoning for datatype
  1007 constructors;
  1008 
  1009 * automatic type-inference, with AddTCs command to insert new
  1010 type-checking rules;
  1011 
  1012 * datatype introduction rules are now added as Safe Introduction rules
  1013 to the claset;
  1014 
  1015 * the syntax "if P then x else y" is now available in addition to
  1016 if(P,x,y);
  1017 
  1018 
  1019 *** Internal programming interfaces ***
  1020 
  1021 * tuned simplifier trace output; new flag debug_simp;
  1022 
  1023 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1024 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1025 
  1026 * AxClass.axclass_tac lost the theory argument;
  1027 
  1028 * tuned current_goals_markers semantics: begin / end goal avoids
  1029 printing empty lines;
  1030 
  1031 * removed prs and prs_fn hook, which was broken because it did not
  1032 include \n in its semantics, forcing writeln to add one
  1033 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1034 string -> unit if you really want to output text without newline;
  1035 
  1036 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1037 plain output, interface builders may have to enable 'isabelle_font'
  1038 mode to get Isabelle font glyphs as before;
  1039 
  1040 * refined token_translation interface; INCOMPATIBILITY: output length
  1041 now of type real instead of int;
  1042 
  1043 * theory loader actions may be traced via new ThyInfo.add_hook
  1044 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1045 your own database of information attached to *whole* theories -- as
  1046 opposed to intra-theory data slots offered via TheoryDataFun;
  1047 
  1048 * proper handling of dangling sort hypotheses (at last!);
  1049 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1050 extra sort hypotheses that can be witnessed from the type signature;
  1051 the force_strip_shyps flag is gone, any remaining shyps are simply
  1052 left in the theorem (with a warning issued by strip_shyps_warning);
  1053 
  1054 
  1055 
  1056 New in Isabelle98-1 (October 1998)
  1057 ----------------------------------
  1058 
  1059 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1060 
  1061 * several changes of automated proof tools;
  1062 
  1063 * HOL: major changes to the inductive and datatype packages, including
  1064 some minor incompatibilities of theory syntax;
  1065 
  1066 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1067 called `inj_on';
  1068 
  1069 * HOL: removed duplicate thms in Arith:
  1070   less_imp_add_less  should be replaced by  trans_less_add1
  1071   le_imp_add_le      should be replaced by  trans_le_add1
  1072 
  1073 * HOL: unary minus is now overloaded (new type constraints may be
  1074 required);
  1075 
  1076 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1077 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1078 now taken as an integer constant.
  1079 
  1080 * Pure: ML function 'theory_of' renamed to 'theory';
  1081 
  1082 
  1083 *** Proof tools ***
  1084 
  1085 * Simplifier:
  1086   1. Asm_full_simp_tac is now more aggressive.
  1087      1. It will sometimes reorient premises if that increases their power to
  1088         simplify.
  1089      2. It does no longer proceed strictly from left to right but may also
  1090         rotate premises to achieve further simplification.
  1091      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1092      old Asm_full_simp_tac in that it does not rotate premises.
  1093   2. The simplifier now knows a little bit about nat-arithmetic.
  1094 
  1095 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1096 allows for selected deletion of wrappers, by introduction of names for
  1097 wrapper functionals.  This implies that addbefore, addSbefore,
  1098 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1099 and that adding two tactics with the same name overwrites the first
  1100 one (emitting a warning).
  1101   type wrapper = (int -> tactic) -> (int -> tactic)
  1102   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1103   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1104   delWrapper, delSWrapper: claset *  string            -> claset
  1105   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1106 
  1107 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1108 semantics; addbefore now affects only the unsafe part of step_tac
  1109 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1110 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1111 by Force_tac;
  1112 
  1113 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1114 compWrapper; added safe wrapper (and access functions for it);
  1115 
  1116 * HOL/split_all_tac is now much faster and fails if there is nothing
  1117 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1118 and the names of the automatically generated variables have changed.
  1119 split_all_tac has moved within claset() from unsafe wrappers to safe
  1120 wrappers, which means that !!-bound variables are split much more
  1121 aggressively, and safe_tac and clarify_tac now split such variables.
  1122 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1123 Note: the same holds for record_split_tac, which does the job of
  1124 split_all_tac for record fields.
  1125 
  1126 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1127 permanently to the default simpset using Addsplits just like
  1128 Addsimps. They can be removed via Delsplits just like
  1129 Delsimps. Lower-case versions are also available.
  1130 
  1131 * HOL/Simplifier: The rule split_if is now part of the default
  1132 simpset. This means that the simplifier will eliminate all occurrences
  1133 of if-then-else in the conclusion of a goal. To prevent this, you can
  1134 either remove split_if completely from the default simpset by
  1135 `Delsplits [split_if]' or remove it in a specific call of the
  1136 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1137 other case splitting rules to/from the default simpset: every datatype
  1138 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1139 t is the name of the datatype).
  1140 
  1141 * Classical reasoner / Simplifier combination: new force_tac (and
  1142 derivatives Force_tac, force) combines rewriting and classical
  1143 reasoning (and whatever other tools) similarly to auto_tac, but is
  1144 aimed to solve the given subgoal completely.
  1145 
  1146 
  1147 *** General ***
  1148 
  1149 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1150 and `goalw': the theory is no longer needed as an explicit argument -
  1151 the current theory context is used; assumptions are no longer returned
  1152 at the ML-level unless one of them starts with ==> or !!; it is
  1153 recommended to convert to these new commands using isatool fixgoal
  1154 (backup your sources first!);
  1155 
  1156 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1157 the current theory context, and 'theory' to lookup stored theories;
  1158 
  1159 * new theory section 'locale' for declaring constants, assumptions and
  1160 definitions that have local scope;
  1161 
  1162 * new theory section 'nonterminals' for purely syntactic types;
  1163 
  1164 * new theory section 'setup' for generic ML setup functions
  1165 (e.g. package initialization);
  1166 
  1167 * the distribution now includes Isabelle icons: see
  1168 lib/logo/isabelle-{small,tiny}.xpm;
  1169 
  1170 * isatool install - install binaries with absolute references to
  1171 ISABELLE_HOME/bin;
  1172 
  1173 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1174 
  1175 * print mode 'emacs' reserved for Isamode;
  1176 
  1177 * support multiple print (ast) translations per constant name;
  1178 
  1179 * theorems involving oracles are now printed with a suffixed [!];
  1180 
  1181 
  1182 *** HOL ***
  1183 
  1184 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1185 
  1186 * HOL/inductive package reorganized and improved: now supports mutual
  1187 definitions such as
  1188 
  1189   inductive EVEN ODD
  1190     intrs
  1191       null "0 : EVEN"
  1192       oddI "n : EVEN ==> Suc n : ODD"
  1193       evenI "n : ODD ==> Suc n : EVEN"
  1194 
  1195 new theorem list "elims" contains an elimination rule for each of the
  1196 recursive sets; inductive definitions now handle disjunctive premises
  1197 correctly (also ZF);
  1198 
  1199 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1200 "mutual_induct" no longer exists - the induction rule is always
  1201 contained in "induct";
  1202 
  1203 
  1204 * HOL/datatype package re-implemented and greatly improved: now
  1205 supports mutually recursive datatypes such as
  1206 
  1207   datatype
  1208     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1209             | SUM ('a aexp) ('a aexp)
  1210             | DIFF ('a aexp) ('a aexp)
  1211             | NUM 'a
  1212   and
  1213     'a bexp = LESS ('a aexp) ('a aexp)
  1214             | AND ('a bexp) ('a bexp)
  1215             | OR ('a bexp) ('a bexp)
  1216 
  1217 as well as indirectly recursive datatypes such as
  1218 
  1219   datatype
  1220     ('a, 'b) term = Var 'a
  1221                   | App 'b ((('a, 'b) term) list)
  1222 
  1223 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1224 induction on mutually / indirectly recursive datatypes.
  1225 
  1226 Primrec equations are now stored in theory and can be accessed via
  1227 <function_name>.simps.
  1228 
  1229 INCOMPATIBILITIES:
  1230 
  1231   - Theories using datatypes must now have theory Datatype as an
  1232     ancestor.
  1233   - The specific <typename>.induct_tac no longer exists - use the
  1234     generic induct_tac instead.
  1235   - natE has been renamed to nat.exhaust - use exhaust_tac
  1236     instead of res_inst_tac ... natE. Note that the variable
  1237     names in nat.exhaust differ from the names in natE, this
  1238     may cause some "fragile" proofs to fail.
  1239   - The theorems split_<typename>_case and split_<typename>_case_asm
  1240     have been renamed to <typename>.split and <typename>.split_asm.
  1241   - Since default sorts of type variables are now handled correctly,
  1242     some datatype definitions may have to be annotated with explicit
  1243     sort constraints.
  1244   - Primrec definitions no longer require function name and type
  1245     of recursive argument.
  1246 
  1247 Consider using isatool fixdatatype to adapt your theories and proof
  1248 scripts to the new package (backup your sources first!).
  1249 
  1250 
  1251 * HOL/record package: considerably improved implementation; now
  1252 includes concrete syntax for record types, terms, updates; theorems
  1253 for surjective pairing and splitting !!-bound record variables; proof
  1254 support is as follows:
  1255 
  1256   1) standard conversions (selectors or updates applied to record
  1257 constructor terms) are part of the standard simpset;
  1258 
  1259   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1260 made part of standard simpset and claset via addIffs;
  1261 
  1262   3) a tactic for record field splitting (record_split_tac) is part of
  1263 the standard claset (addSWrapper);
  1264 
  1265 To get a better idea about these rules you may retrieve them via
  1266 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1267 the name of your record type.
  1268 
  1269 The split tactic 3) conceptually simplifies by the following rule:
  1270 
  1271   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1272 
  1273 Thus any record variable that is bound by meta-all will automatically
  1274 blow up into some record constructor term, consequently the
  1275 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1276 solve record problems automatically.
  1277 
  1278 
  1279 * reorganized the main HOL image: HOL/Integ and String loaded by
  1280 default; theory Main includes everything;
  1281 
  1282 * automatic simplification of integer sums and comparisons, using cancellation;
  1283 
  1284 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1285 
  1286 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1287 
  1288 * many new identities for unions, intersections, set difference, etc.;
  1289 
  1290 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1291 called split_if, split_split, split_sum_case and split_nat_case (to go
  1292 with add/delsplits);
  1293 
  1294 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1295 (?x::unit) = (); this is made part of the default simpset, which COULD
  1296 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1297 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1298 unit_abs_eta_conv is added in order to counter the effect of
  1299 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1300 %u.f();
  1301 
  1302 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1303 makes more sense);
  1304 
  1305 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1306   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1307   disjointness reasoning but breaking a few old proofs.
  1308 
  1309 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1310 to 'converse' from 'inverse' (for compatibility with ZF and some
  1311 literature);
  1312 
  1313 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1314 the well-founded relation;
  1315 
  1316 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1317     Compl A.  The "Compl" syntax remains available as input syntax for this
  1318     release ONLY.
  1319 
  1320 * HOL/Update: new theory of function updates:
  1321     f(a:=b) == %x. if x=a then b else f x
  1322 may also be iterated as in f(a:=b,c:=d,...);
  1323 
  1324 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1325 
  1326 * HOL/List:
  1327   - new function list_update written xs[i:=v] that updates the i-th
  1328     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1329   - new function `upt' written [i..j(] which generates the list
  1330     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1331     bound write [i..j], which is a shorthand for [i..j+1(].
  1332   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1333 
  1334 * HOL/Arith:
  1335   - removed 'pred' (predecessor) function;
  1336   - generalized some theorems about n-1;
  1337   - many new laws about "div" and "mod";
  1338   - new laws about greatest common divisors (see theory ex/Primes);
  1339 
  1340 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1341 instead of "inverse";
  1342 
  1343 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1344   of the multiset ordering;
  1345 
  1346 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1347   (not included by default);
  1348 
  1349 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1350 
  1351 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1352   programs, i.e. different program variables may have different types.
  1353 
  1354 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1355   [previously, this check worked only if the rewrite rule was unconditional]
  1356   Now rew can involve either definitions or equalities (either == or =).
  1357 
  1358 
  1359 *** ZF ***
  1360 
  1361 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1362   only the theorems proved on ZF.ML;
  1363 
  1364 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1365   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1366   disjointness reasoning but breaking a few old proofs.
  1367 
  1368 * ZF/Update: new theory of function updates
  1369     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1370   may also be iterated as in f(a:=b,c:=d,...);
  1371 
  1372 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1373 
  1374 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1375   [previously, this check worked only if the rewrite rule was unconditional]
  1376   Now rew can involve either definitions or equalities (either == or =).
  1377 
  1378 * case_tac provided for compatibility with HOL
  1379     (like the old excluded_middle_tac, but with subgoals swapped)
  1380 
  1381 
  1382 *** Internal programming interfaces ***
  1383 
  1384 * Pure: several new basic modules made available for general use, see
  1385 also src/Pure/README;
  1386 
  1387 * improved the theory data mechanism to support encapsulation (data
  1388 kind name replaced by private Object.kind, acting as authorization
  1389 key); new type-safe user interface via functor TheoryDataFun; generic
  1390 print_data function becomes basically useless;
  1391 
  1392 * removed global_names compatibility flag -- all theory declarations
  1393 are qualified by default;
  1394 
  1395 * module Pure/Syntax now offers quote / antiquote translation
  1396 functions (useful for Hoare logic etc. with implicit dependencies);
  1397 see HOL/ex/Antiquote for an example use;
  1398 
  1399 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1400 cterm -> thm;
  1401 
  1402 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1403 subgoal;
  1404 
  1405 * Display.print_goals function moved to Locale.print_goals;
  1406 
  1407 * standard print function for goals supports current_goals_markers
  1408 variable for marking begin of proof, end of proof, start of goal; the
  1409 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1410 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1411 for example;
  1412 
  1413 
  1414 
  1415 New in Isabelle98 (January 1998)
  1416 --------------------------------
  1417 
  1418 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1419 
  1420 * changed lexical syntax of terms / types: dots made part of long
  1421 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1422 
  1423 * simpset (and claset) reference variable replaced by functions
  1424 simpset / simpset_ref;
  1425 
  1426 * no longer supports theory aliases (via merge) and non-trivial
  1427 implicit merge of thms' signatures;
  1428 
  1429 * most internal names of constants changed due to qualified names;
  1430 
  1431 * changed Pure/Sequence interface (see Pure/seq.ML);
  1432 
  1433 
  1434 *** General Changes ***
  1435 
  1436 * hierachically structured name spaces (for consts, types, axms, thms
  1437 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1438 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1439 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1440 long_names for fully qualified output names; NOTE: ML programs
  1441 (special tactics, packages etc.) referring to internal names may have
  1442 to be adapted to cope with fully qualified names; in case of severe
  1443 backward campatibility problems try setting 'global_names' at compile
  1444 time to have enrything declared within a flat name space; one may also
  1445 fine tune name declarations in theories via the 'global' and 'local'
  1446 section;
  1447 
  1448 * reimplemented the implicit simpset and claset using the new anytype
  1449 data filed in signatures; references simpset:simpset ref etc. are
  1450 replaced by functions simpset:unit->simpset and
  1451 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1452 to patch your ML files accordingly;
  1453 
  1454 * HTML output now includes theory graph data for display with Java
  1455 applet or isatool browser; data generated automatically via isatool
  1456 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1457 
  1458 * defs may now be conditional; improved rewrite_goals_tac to handle
  1459 conditional equations;
  1460 
  1461 * defs now admits additional type arguments, using TYPE('a) syntax;
  1462 
  1463 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1464 creates a new theory node; implicit merge of thms' signatures is
  1465 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1466 transfer:theory->thm->thm in (rare) cases;
  1467 
  1468 * improved handling of draft signatures / theories; draft thms (and
  1469 ctyps, cterms) are automatically promoted to real ones;
  1470 
  1471 * slightly changed interfaces for oracles: admit many per theory, named
  1472 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1473 
  1474 * print_goals: optional output of const types (set show_consts and
  1475 show_types);
  1476 
  1477 * improved output of warnings (###) and errors (***);
  1478 
  1479 * subgoal_tac displays a warning if the new subgoal has type variables;
  1480 
  1481 * removed old README and Makefiles;
  1482 
  1483 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1484 
  1485 * removed obsolete init_pps and init_database;
  1486 
  1487 * deleted the obsolete tactical STATE, which was declared by
  1488     fun STATE tacfun st = tacfun st st;
  1489 
  1490 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1491 (which abbreviates $HOME);
  1492 
  1493 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1494 use isatool fixseq to adapt your ML programs (this works for fully
  1495 qualified references to the Sequence structure only!);
  1496 
  1497 * use_thy no longer requires writable current directory; it always
  1498 reloads .ML *and* .thy file, if either one is out of date;
  1499 
  1500 
  1501 *** Classical Reasoner ***
  1502 
  1503 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1504 tactics that use classical reasoning to simplify a subgoal without
  1505 splitting it into several subgoals;
  1506 
  1507 * Safe_tac: like safe_tac but uses the default claset;
  1508 
  1509 
  1510 *** Simplifier ***
  1511 
  1512 * added simplification meta rules:
  1513     (asm_)(full_)simplify: simpset -> thm -> thm;
  1514 
  1515 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1516 logics (again);
  1517 
  1518 * added prems argument to simplification procedures;
  1519 
  1520 * HOL, FOL, ZF: added infix function `addsplits':
  1521   instead of `<simpset> setloop (split_tac <thms>)'
  1522   you can simply write `<simpset> addsplits <thms>'
  1523 
  1524 
  1525 *** Syntax ***
  1526 
  1527 * TYPE('a) syntax for type reflection terms;
  1528 
  1529 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1530 
  1531 * pretty printer: changed order of mixfix annotation preference (again!);
  1532 
  1533 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1534 
  1535 
  1536 *** HOL ***
  1537 
  1538 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1539   with `addloop' of the simplifier to faciliate case splitting in premises.
  1540 
  1541 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1542 
  1543 * HOL/Auth: new protocol proofs including some for the Internet
  1544   protocol TLS;
  1545 
  1546 * HOL/Map: new theory of `maps' a la VDM;
  1547 
  1548 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1549 cancelling out common nat summands from =, <, <= (in)equalities, or
  1550 differences; simplification procedures nat_cancel_factor for
  1551 cancelling common factor from =, <, <= (in)equalities over natural
  1552 sums; nat_cancel contains both kinds of procedures, it is installed by
  1553 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1554 
  1555 * HOL/simplifier: terms of the form
  1556   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1557   are rewritten to
  1558   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1559   and those of the form
  1560   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1561   are rewritten to
  1562   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1563 
  1564 * HOL/datatype
  1565   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1566 
  1567   P(t_case f1 ... fn x) =
  1568      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1569         ...
  1570        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1571      )
  1572 
  1573   and a theorem `split_t_case_asm' of the form
  1574 
  1575   P(t_case f1 ... fn x) =
  1576     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1577         ...
  1578        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1579      )
  1580   which can be added to a simpset via `addsplits'. The existing theorems
  1581   expand_list_case and expand_option_case have been renamed to
  1582   split_list_case and split_option_case.
  1583 
  1584 * HOL/Arithmetic:
  1585   - `pred n' is automatically converted to `n-1'.
  1586     Users are strongly encouraged not to use `pred' any longer,
  1587     because it will disappear altogether at some point.
  1588   - Users are strongly encouraged to write "0 < n" rather than
  1589     "n ~= 0". Theorems and proof tools have been modified towards this
  1590     `standard'.
  1591 
  1592 * HOL/Lists:
  1593   the function "set_of_list" has been renamed "set" (and its theorems too);
  1594   the function "nth" now takes its arguments in the reverse order and
  1595   has acquired the infix notation "!" as in "xs!n".
  1596 
  1597 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1598 
  1599 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1600   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1601 
  1602 * HOL/record: extensible records with schematic structural subtyping
  1603 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1604 still lacks various theorems and concrete record syntax;
  1605 
  1606 
  1607 *** HOLCF ***
  1608 
  1609 * removed "axioms" and "generated by" sections;
  1610 
  1611 * replaced "ops" section by extended "consts" section, which is capable of
  1612   handling the continuous function space "->" directly;
  1613 
  1614 * domain package:
  1615   . proves theorems immediately and stores them in the theory,
  1616   . creates hierachical name space,
  1617   . now uses normal mixfix annotations (instead of cinfix...),
  1618   . minor changes to some names and values (for consistency),
  1619   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1620   . separator between mutual domain defs: changed "," to "and",
  1621   . improved handling of sort constraints;  now they have to
  1622     appear on the left-hand side of the equations only;
  1623 
  1624 * fixed LAM <x,y,zs>.b syntax;
  1625 
  1626 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1627 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1628 
  1629 
  1630 *** FOL and ZF ***
  1631 
  1632 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1633   with `addloop' of the simplifier to faciliate case splitting in premises.
  1634 
  1635 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1636 in HOL, they strip ALL and --> from proved theorems;
  1637 
  1638 
  1639 
  1640 New in Isabelle94-8 (May 1997)
  1641 ------------------------------
  1642 
  1643 *** General Changes ***
  1644 
  1645 * new utilities to build / run / maintain Isabelle etc. (in parts
  1646 still somewhat experimental); old Makefiles etc. still functional;
  1647 
  1648 * new 'Isabelle System Manual';
  1649 
  1650 * INSTALL text, together with ./configure and ./build scripts;
  1651 
  1652 * reimplemented type inference for greater efficiency, better error
  1653 messages and clean internal interface;
  1654 
  1655 * prlim command for dealing with lots of subgoals (an easier way of
  1656 setting goals_limit);
  1657 
  1658 
  1659 *** Syntax ***
  1660 
  1661 * supports alternative (named) syntax tables (parser and pretty
  1662 printer); internal interface is provided by add_modesyntax(_i);
  1663 
  1664 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1665 be used in conjunction with the Isabelle symbol font; uses the
  1666 "symbols" syntax table;
  1667 
  1668 * added token_translation interface (may translate name tokens in
  1669 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1670 the current print_mode); IMPORTANT: user print translation functions
  1671 are responsible for marking newly introduced bounds
  1672 (Syntax.mark_boundT);
  1673 
  1674 * token translations for modes "xterm" and "xterm_color" that display
  1675 names in bold, underline etc. or colors (which requires a color
  1676 version of xterm);
  1677 
  1678 * infixes may now be declared with names independent of their syntax;
  1679 
  1680 * added typed_print_translation (like print_translation, but may
  1681 access type of constant);
  1682 
  1683 
  1684 *** Classical Reasoner ***
  1685 
  1686 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1687 some limitations.  Blast_tac...
  1688   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1689   + ignores elimination rules that don't have the correct format
  1690         (the conclusion MUST be a formula variable)
  1691   + ignores types, which can make HOL proofs fail
  1692   + rules must not require higher-order unification, e.g. apply_type in ZF
  1693     [message "Function Var's argument not a bound variable" relates to this]
  1694   + its proof strategy is more general but can actually be slower
  1695 
  1696 * substitution with equality assumptions no longer permutes other
  1697 assumptions;
  1698 
  1699 * minor changes in semantics of addafter (now called addaltern); renamed
  1700 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1701 (and access functions for it);
  1702 
  1703 * improved combination of classical reasoner and simplifier:
  1704   + functions for handling clasimpsets
  1705   + improvement of addss: now the simplifier is called _after_ the
  1706     safe steps.
  1707   + safe variant of addss called addSss: uses safe simplifications
  1708     _during_ the safe steps. It is more complete as it allows multiple
  1709     instantiations of unknowns (e.g. with slow_tac).
  1710 
  1711 *** Simplifier ***
  1712 
  1713 * added interface for simplification procedures (functions that
  1714 produce *proven* rewrite rules on the fly, depending on current
  1715 redex);
  1716 
  1717 * ordering on terms as parameter (used for ordered rewriting);
  1718 
  1719 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1720 
  1721 * the solver is now split into a safe and an unsafe part.
  1722 This should be invisible for the normal user, except that the
  1723 functions setsolver and addsolver have been renamed to setSolver and
  1724 addSolver; added safe_asm_full_simp_tac;
  1725 
  1726 
  1727 *** HOL ***
  1728 
  1729 * a generic induction tactic `induct_tac' which works for all datatypes and
  1730 also for type `nat';
  1731 
  1732 * a generic case distinction tactic `exhaust_tac' which works for all
  1733 datatypes and also for type `nat';
  1734 
  1735 * each datatype comes with a function `size';
  1736 
  1737 * patterns in case expressions allow tuple patterns as arguments to
  1738 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1739 
  1740 * primrec now also works with type nat;
  1741 
  1742 * recdef: a new declaration form, allows general recursive functions to be
  1743 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1744 
  1745 * the constant for negation has been renamed from "not" to "Not" to
  1746 harmonize with FOL, ZF, LK, etc.;
  1747 
  1748 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1749 infinite lists;
  1750 
  1751 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1752 
  1753 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1754 problems in commutative rings, using axiomatic type classes for + and *;
  1755 
  1756 * more examples in HOL/MiniML and HOL/Auth;
  1757 
  1758 * more default rewrite rules for quantifiers, union/intersection;
  1759 
  1760 * a new constant `arbitrary == @x.False';
  1761 
  1762 * HOLCF/IOA replaces old HOL/IOA;
  1763 
  1764 * HOLCF changes: derived all rules and arities
  1765   + axiomatic type classes instead of classes
  1766   + typedef instead of faking type definitions
  1767   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1768   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1769   + eliminated the types void, one, tr
  1770   + use unit lift and bool lift (with translations) instead of one and tr
  1771   + eliminated blift from Lift3.thy (use Def instead of blift)
  1772   all eliminated rules are derived as theorems --> no visible changes ;
  1773 
  1774 
  1775 *** ZF ***
  1776 
  1777 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1778 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1779 as ZF_cs addSIs [equalityI];
  1780 
  1781 
  1782 
  1783 New in Isabelle94-7 (November 96)
  1784 ---------------------------------
  1785 
  1786 * allowing negative levels (as offsets) in prlev and choplev;
  1787 
  1788 * super-linear speedup for large simplifications;
  1789 
  1790 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1791 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1792 FAIL); can suppress it using the command Delsimps (ex_simps @
  1793 all_simps); De Morgan laws are also now included, by default;
  1794 
  1795 * improved printing of ==>  :  ~:
  1796 
  1797 * new object-logic "Sequents" adds linear logic, while replacing LK
  1798 and Modal (thanks to Sara Kalvala);
  1799 
  1800 * HOL/Auth: correctness proofs for authentication protocols;
  1801 
  1802 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1803 examples on HOL/Auth);
  1804 
  1805 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1806 the rewriter and classical reasoner simultaneously;
  1807 
  1808 * function uresult no longer returns theorems in "standard" format;
  1809 regain previous version by: val uresult = standard o uresult;
  1810 
  1811 
  1812 
  1813 New in Isabelle94-6
  1814 -------------------
  1815 
  1816 * oracles -- these establish an interface between Isabelle and trusted
  1817 external reasoners, which may deliver results as theorems;
  1818 
  1819 * proof objects (in particular record all uses of oracles);
  1820 
  1821 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1822 
  1823 * "constdefs" section in theory files;
  1824 
  1825 * "primrec" section (HOL) no longer requires names;
  1826 
  1827 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1828 
  1829 
  1830 
  1831 New in Isabelle94-5
  1832 -------------------
  1833 
  1834 * reduced space requirements;
  1835 
  1836 * automatic HTML generation from theories;
  1837 
  1838 * theory files no longer require "..." (quotes) around most types;
  1839 
  1840 * new examples, including two proofs of the Church-Rosser theorem;
  1841 
  1842 * non-curried (1994) version of HOL is no longer distributed;
  1843 
  1844 
  1845 
  1846 New in Isabelle94-4
  1847 -------------------
  1848 
  1849 * greatly reduced space requirements;
  1850 
  1851 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1852 
  1853 * searchable theorem database (see the section "Retrieving theorems" on
  1854 page 8 of the Reference Manual);
  1855 
  1856 * new examples, including Grabczewski's monumental case study of the
  1857 Axiom of Choice;
  1858 
  1859 * The previous version of HOL renamed to Old_HOL;
  1860 
  1861 * The new version of HOL (previously called CHOL) uses a curried syntax
  1862 for functions.  Application looks like f a b instead of f(a,b);
  1863 
  1864 * Mutually recursive inductive definitions finally work in HOL;
  1865 
  1866 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1867 translates to the operator "split";
  1868 
  1869 
  1870 
  1871 New in Isabelle94-3
  1872 -------------------
  1873 
  1874 * new infix operator, addss, allowing the classical reasoner to
  1875 perform simplification at each step of its search.  Example:
  1876         fast_tac (cs addss ss)
  1877 
  1878 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1879 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1880 look like (a,b) instead of <a,b>;
  1881 
  1882 * PLEASE NOTE: CHOL will eventually replace HOL!
  1883 
  1884 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1885 It translates to the operator "split".  A new theory of integers is available;
  1886 
  1887 * In ZF, integer numerals now denote two's-complement binary integers.
  1888 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1889 
  1890 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1891 of the Axiom of Choice;
  1892 
  1893 
  1894 
  1895 New in Isabelle94-2
  1896 -------------------
  1897 
  1898 * Significantly faster resolution;
  1899 
  1900 * the different sections in a .thy file can now be mixed and repeated
  1901 freely;
  1902 
  1903 * Database of theorems for FOL, HOL and ZF.  New
  1904 commands including qed, qed_goal and bind_thm store theorems in the database.
  1905 
  1906 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1907 a given theory (thms_of), or find out what theory a theorem was proved in
  1908 (theory_of_thm);
  1909 
  1910 * Bugs fixed in the inductive definition and datatype packages;
  1911 
  1912 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1913 and HOL_dup_cs obsolete;
  1914 
  1915 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1916 have been removed;
  1917 
  1918 * Simpler definition of function space in ZF;
  1919 
  1920 * new results about cardinal and ordinal arithmetic in ZF;
  1921 
  1922 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1923 types;
  1924 
  1925 
  1926 $Id$