NEWS
author wenzelm
Fri Oct 26 23:58:21 2001 +0200 (2001-10-26)
changeset 11952 b10f1e8862f4
parent 11937 2a2b1182a23b
child 11965 c84eb86d9a5f
permissions -rw-r--r--
* Pure: method 'atomize' presents local goal premises as object-level
statements (atomic meta-level propositions); setup controlled via
rewrite rules declarations of 'atomize' attribute; example
application: 'induct' method with proper rule statements in improper
proof *scripts*;
     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 * Pure: removed obsolete 'exported' attribute;
    56 
    57 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    58 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    59 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    60 
    61 * Pure: method 'atomize' presents local goal premises as object-level
    62 statements (atomic meta-level propositions); setup controlled via
    63 rewrite rules declarations of 'atomize' attribute; example
    64 application: 'induct' method with proper rule statements in improper
    65 proof *scripts*;
    66 
    67 * Provers: 'simplified' attribute may refer to explicit rules instead
    68 of full simplifier context; 'iff' attribute handles conditional rules;
    69 
    70 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
    71 
    72 * HOL: 'recdef' now fails on unfinished automated proofs, use
    73 "(permissive)" option to recover old behavior;
    74 
    75 * HOL: 'inductive' no longer features separate (collective) attributes
    76 for 'intros' (was found too confusing);
    77 
    78 
    79 
    80 *** HOL ***
    81 
    82 * HOL: moved over to sane numeral syntax; the new policy is as
    83 follows:
    84 
    85   - 0 and 1 are polymorphic constants, which are defined on any
    86   numeric type (nat, int, real etc.);
    87 
    88   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
    89   binary representation internally;
    90 
    91   - type nat has special constructor Suc, and generally prefers Suc 0
    92   over 1::nat and Suc (Suc 0) over 2::nat;
    93 
    94 This change may cause significant INCOMPATIBILITIES; here are some
    95 hints on converting existing sources:
    96 
    97   - due to the new "num" token, "-0" and "-1" etc. are now atomic
    98   entities, so expressions involving "-" (unary or binary minus) need
    99   to be spaced properly;
   100 
   101   - existing occurrences of "1" may need to be constraint "1::nat" or
   102   even replaced by Suc 0; similar for old "2";
   103 
   104   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   105 
   106   - remove all special provisions on numerals in proofs;
   107 
   108 * HOL/record:
   109   - removed old "make" and "make_scheme" operations -- INCOMPATIBILITY;
   110   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   111   - provides cases/induct rules for use with corresponding Isar methods;
   112   - new derived operations "make" (for adding fields of current
   113     record), "extend" to promote fixed record to record scheme, and
   114     "truncate" for the reverse; cf. theorems "derived_defs", which are
   115     *not* declared as simp by default;
   116   - internal definitions directly based on a light-weight abstract
   117     theory of product types over typedef rather than datatype;
   118 
   119 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   120 
   121 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   122 (beware of argument permutation!);
   123 
   124 * HOL: linorder_less_split superseded by linorder_cases;
   125 
   126 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   127 to peripheral theory "Hilbert_Choice";
   128 
   129 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   130 in this (rare) case use:
   131 
   132   delSWrapper "split_all_tac"
   133   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   134 
   135 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   136 MAY FAIL;
   137 
   138 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   139 Isabelle's type classes, ^ on functions and relations has too general
   140 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   141 necessary to attach explicit type constraints;
   142 
   143 * HOL: syntax translations now work properly with numerals and records
   144 expressions;
   145 
   146 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   147 Florian Kammüller;
   148 
   149 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   150 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   151 renamed "Product_Type.unit";
   152 
   153 
   154 *** ZF ***
   155 
   156 * ZF: the integer library now covers quotients and remainders, with
   157 many laws relating division to addition, multiplication, etc.;
   158 
   159 
   160 *** General ***
   161 
   162 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   163 manual;
   164 
   165 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   166 
   167 * clasimp: ``iff'' declarations now handle conditional rules as well;
   168 
   169 * syntax: new token syntax "num" for plain numerals (without "#" of
   170 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   171 tokens, so expressions involving minus need to be spaced properly;
   172 
   173 * syntax: support non-oriented infixes;
   174 
   175 * syntax: print modes "type_brackets" and "no_type_brackets" control
   176 output of nested => (types); the default behavior is "type_brackets";
   177 
   178 * syntax: builtin parse translation for "_constify" turns valued
   179 tokens into AST constants;
   180 
   181 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   182 
   183 * system: Proof General keywords specification is now part of the
   184 Isabelle distribution (see etc/isar-keywords.el);
   185 
   186 * system: smart selection of Isabelle process versus Isabelle
   187 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   188 run both "isabelle" and "Isabelle" even if file names are badly
   189 damaged (executable inspects the case of the first letter of its own
   190 name); added separate "isabelle-process" and "isabelle-interface";
   191 
   192 
   193 
   194 New in Isabelle99-2 (February 2001)
   195 -----------------------------------
   196 
   197 *** Overview of INCOMPATIBILITIES ***
   198 
   199 * HOL: please note that theories in the Library and elsewhere often use the
   200 new-style (Isar) format; to refer to their theorems in an ML script you must
   201 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   202 
   203 * HOL: inductive package no longer splits induction rule aggressively,
   204 but only as far as specified by the introductions given; the old
   205 format may be recovered via ML function complete_split_rule or attribute
   206 'split_rule (complete)';
   207 
   208 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   209 gfp_Tarski to gfp_unfold;
   210 
   211 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   212 
   213 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   214 relation); infix "^^" has been renamed "``"; infix "``" has been
   215 renamed "`"; "univalent" has been renamed "single_valued";
   216 
   217 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   218 operation;
   219 
   220 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   221 
   222 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   223 
   224 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   225 consequence, it is no longer monotonic wrt. the local goal context
   226 (which is now passed through the inductive cases);
   227 
   228 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   229 \<gg> to \<ggreater>;
   230 
   231 
   232 *** Document preparation ***
   233 
   234 * \isabellestyle{NAME} selects version of Isabelle output (currently
   235 available: are "it" for near math-mode best-style output, "sl" for
   236 slanted text style, and "tt" for plain type-writer; if no
   237 \isabellestyle command is given, output is according to slanted
   238 type-writer);
   239 
   240 * support sub/super scripts (for single symbols only), input syntax is
   241 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   242 
   243 * some more standard symbols; see Appendix A of the system manual for
   244 the complete list of symbols defined in isabellesym.sty;
   245 
   246 * improved isabelle style files; more abstract symbol implementation
   247 (should now use \isamath{...} and \isatext{...} in custom symbol
   248 definitions);
   249 
   250 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   251 state; Note that presentation of goal states does not conform to
   252 actual human-readable proof documents.  Please do not include goal
   253 states into document output unless you really know what you are doing!
   254 
   255 * proper indentation of antiquoted output with proportional LaTeX
   256 fonts;
   257 
   258 * no_document ML operator temporarily disables LaTeX document
   259 generation;
   260 
   261 * isatool unsymbolize tunes sources for plain ASCII communication;
   262 
   263 
   264 *** Isar ***
   265 
   266 * Pure: Isar now suffers initial goal statements to contain unbound
   267 schematic variables (this does not conform to actual readable proof
   268 documents, due to unpredictable outcome and non-compositional proof
   269 checking); users who know what they are doing may use schematic goals
   270 for Prolog-style synthesis of proven results;
   271 
   272 * Pure: assumption method (an implicit finishing) now handles actual
   273 rules as well;
   274 
   275 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   276 initial goal, declare "that" only as Pure intro (only for single
   277 steps); the "that" rule assumption may now be involved in implicit
   278 finishing, thus ".." becomes a feasible for trivial obtains;
   279 
   280 * Pure: default proof step now includes 'intro_classes'; thus trivial
   281 instance proofs may be performed by "..";
   282 
   283 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   284 statements as well;
   285 
   286 * Pure: more robust selection of calculational rules;
   287 
   288 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   289 rule (as well as the assumption rule);
   290 
   291 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   292 lemmas, using the graph browser tool;
   293 
   294 * Pure: predict failure of "show" in interactive mode;
   295 
   296 * Pure: 'thms_containing' now takes actual terms as arguments;
   297 
   298 * HOL: improved method 'induct' --- now handles non-atomic goals
   299 (potential INCOMPATIBILITY); tuned error handling;
   300 
   301 * HOL: cases and induct rules now provide explicit hints about the
   302 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   303 any remaining facts are inserted into the goal verbatim;
   304 
   305 * HOL: local contexts (aka cases) may now contain term bindings as
   306 well; the 'cases' and 'induct' methods new provide a ?case binding for
   307 the result to be shown in each case;
   308 
   309 * HOL: added 'recdef_tc' command;
   310 
   311 * isatool convert assists in eliminating legacy ML scripts;
   312 
   313 
   314 *** HOL ***
   315 
   316 * HOL/Library: a collection of generic theories to be used together
   317 with main HOL; the theory loader path already includes this directory
   318 by default; the following existing theories have been moved here:
   319 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   320 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   321 
   322 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   323 modelling and verification task performed in Isabelle/HOL +
   324 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   325 
   326 * HOL/Algebra: special summation operator SUM no longer exists, it has
   327 been replaced by setsum; infix 'assoc' now has priority 50 (like
   328 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   329 'domain', this makes the theory consistent with mathematical
   330 literature;
   331 
   332 * HOL basics: added overloaded operations "inverse" and "divide"
   333 (infix "/"), syntax for generic "abs" operation, generic summation
   334 operator \<Sum>;
   335 
   336 * HOL/typedef: simplified package, provide more useful rules (see also
   337 HOL/subset.thy);
   338 
   339 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   340 now expressed as a proper nested rule (old-style tactic scripts may
   341 require atomize_strip_tac to cope with non-atomic premises);
   342 
   343 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   344 to "split_conv" (old name still available for compatibility);
   345 
   346 * HOL: improved concrete syntax for strings (e.g. allows translation
   347 rules with string literals);
   348 
   349 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   350 and Fleuriot's mechanization of analysis;
   351 
   352 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   353 
   354 
   355 *** CTT ***
   356 
   357 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   358 "lam" is displayed as TWO lambda-symbols
   359 
   360 * CTT: theory Main now available, containing everything (that is, Bool
   361 and Arith);
   362 
   363 
   364 *** General ***
   365 
   366 * Pure: the Simplifier has been implemented properly as a derived rule
   367 outside of the actual kernel (at last!); the overall performance
   368 penalty in practical applications is about 50%, while reliability of
   369 the Isabelle inference kernel has been greatly improved;
   370 
   371 * print modes "brackets" and "no_brackets" control output of nested =>
   372 (types) and ==> (props); the default behaviour is "brackets";
   373 
   374 * Provers: fast_tac (and friends) now handle actual object-logic rules
   375 as assumptions as well;
   376 
   377 * system: support Poly/ML 4.0;
   378 
   379 * system: isatool install handles KDE version 1 or 2;
   380 
   381 
   382 
   383 New in Isabelle99-1 (October 2000)
   384 ----------------------------------
   385 
   386 *** Overview of INCOMPATIBILITIES ***
   387 
   388 * HOL: simplification of natural numbers is much changed; to partly
   389 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   390 issue the following ML commands:
   391 
   392   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   393   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   394 
   395 * HOL: simplification no longer dives into case-expressions; this is
   396 controlled by "t.weak_case_cong" for each datatype t;
   397 
   398 * HOL: nat_less_induct renamed to less_induct;
   399 
   400 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   401 fixsome to patch .thy and .ML sources automatically;
   402 
   403   select_equality  -> some_equality
   404   select_eq_Ex     -> some_eq_ex
   405   selectI2EX       -> someI2_ex
   406   selectI2         -> someI2
   407   selectI          -> someI
   408   select1_equality -> some1_equality
   409   Eps_sym_eq       -> some_sym_eq_trivial
   410   Eps_eq           -> some_eq_trivial
   411 
   412 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   413 
   414 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   415 instead);
   416 
   417 * HOL: the recursion equations generated by 'recdef' are now called
   418 f.simps instead of f.rules;
   419 
   420 * HOL: qed_spec_mp now also handles bounded ALL as well;
   421 
   422 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   423 sometimes be needed;
   424 
   425 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   426 
   427 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   428 
   429 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   430 product is now "<*>" instead of "Times"; the lexicographic product is
   431 now "<*lex*>" instead of "**";
   432 
   433 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   434 of main HOL, but was unused); better use HOL's datatype package;
   435 
   436 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   437 the old syntax may be recovered as follows:
   438 
   439   syntax (symbols)
   440     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   441       (infixl "\\<oplus>" 100)
   442 
   443 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   444 
   445 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   446 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   447 internally;
   448 
   449 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   450 changed from A/r to A//r;
   451 
   452 * ZF: new treatment of arithmetic (nat & int) may break some old
   453 proofs;
   454 
   455 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   456 rulify -> rule_format, elimify -> elim_format, ...);
   457 
   458 * Isar/Provers: intro/elim/dest attributes changed; renamed
   459 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   460 should have to change intro!! to intro? only); replaced "delrule" by
   461 "rule del";
   462 
   463 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   464 
   465 * Provers: strengthened force_tac by using new first_best_tac;
   466 
   467 * LaTeX document preparation: several changes of isabelle.sty (see
   468 lib/texinputs);
   469 
   470 
   471 *** Document preparation ***
   472 
   473 * formal comments (text blocks etc.) in new-style theories may now
   474 contain antiquotations of thm/prop/term/typ/text to be presented
   475 according to latex print mode; concrete syntax is like this:
   476 @{term[show_types] "f(x) = a + x"};
   477 
   478 * isatool mkdir provides easy setup of Isabelle session directories,
   479 including proper document sources;
   480 
   481 * generated LaTeX sources are now deleted after successful run
   482 (isatool document -c); may retain a copy somewhere else via -D option
   483 of isatool usedir;
   484 
   485 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   486 style files, achieving self-contained LaTeX sources and simplifying
   487 LaTeX debugging;
   488 
   489 * old-style theories now produce (crude) LaTeX output as well;
   490 
   491 * browser info session directories are now self-contained (may be put
   492 on WWW server seperately); improved graphs of nested sessions; removed
   493 graph for 'all sessions';
   494 
   495 * several improvements in isabelle style files; \isabellestyle{it}
   496 produces fake math mode output; \isamarkupheader is now \section by
   497 default; see lib/texinputs/isabelle.sty etc.;
   498 
   499 
   500 *** Isar ***
   501 
   502 * Isar/Pure: local results and corresponding term bindings are now
   503 subject to Hindley-Milner polymorphism (similar to ML); this
   504 accommodates incremental type-inference very nicely;
   505 
   506 * Isar/Pure: new derived language element 'obtain' supports
   507 generalized existence reasoning;
   508 
   509 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   510 support accumulation of results, without applying any rules yet;
   511 useful to collect intermediate results without explicit name
   512 references, and for use with transitivity rules with more than 2
   513 premises;
   514 
   515 * Isar/Pure: scalable support for case-analysis type proofs: new
   516 'case' language element refers to local contexts symbolically, as
   517 produced by certain proof methods; internally, case names are attached
   518 to theorems as "tags";
   519 
   520 * Isar/Pure: theory command 'hide' removes declarations from
   521 class/type/const name spaces;
   522 
   523 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   524 indicate potential overloading;
   525 
   526 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   527 
   528 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   529 "{a,b,c}" instead of {a,b,c};
   530 
   531 * Isar/Pure now provides its own version of intro/elim/dest
   532 attributes; useful for building new logics, but beware of confusion
   533 with the version in Provers/classical;
   534 
   535 * Isar/Pure: the local context of (non-atomic) goals is provided via
   536 case name 'antecedent';
   537 
   538 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   539 to the current context is now done automatically);
   540 
   541 * Isar/Pure: theory command 'method_setup' provides a simple interface
   542 for definining proof methods in ML;
   543 
   544 * Isar/Provers: intro/elim/dest attributes changed; renamed
   545 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   546 most cases, one should have to change intro!! to intro? only);
   547 replaced "delrule" by "rule del";
   548 
   549 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   550 'symmetric' attribute (the latter supercedes [RS sym]);
   551 
   552 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   553 method modifier); 'simp' method: 'only:' modifier removes loopers as
   554 well (including splits);
   555 
   556 * Isar/Provers: Simplifier and Classical methods now support all kind
   557 of modifiers used in the past, including 'cong', 'iff', etc.
   558 
   559 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   560 of Simplifier and Classical reasoner);
   561 
   562 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   563 now support named cases; major packages (inductive, datatype, primrec,
   564 recdef) support case names and properly name parameters;
   565 
   566 * Isar/HOL: new transitivity rules for substitution in inequalities --
   567 monotonicity conditions are extracted to be proven at end of
   568 calculations;
   569 
   570 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   571 method anyway;
   572 
   573 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   574 split_if split_if_asm; datatype package provides theorems foo.splits =
   575 foo.split foo.split_asm for each datatype;
   576 
   577 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   578 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   579 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   580 use "(cases (simplified))" method in proper proof texts);
   581 
   582 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   583 
   584 * Isar: names of theorems etc. may be natural numbers as well;
   585 
   586 * Isar: 'pr' command: optional arguments for goals_limit and
   587 ProofContext.prems_limit; no longer prints theory contexts, but only
   588 proof states;
   589 
   590 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   591 additional print modes to be specified; e.g. "pr(latex)" will print
   592 proof state according to the Isabelle LaTeX style;
   593 
   594 * Isar: improved support for emulating tactic scripts, including proof
   595 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   596 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   597 (for HOL datatypes);
   598 
   599 * Isar: simplified (more robust) goal selection of proof methods: 1st
   600 goal, all goals, or explicit goal specifier (tactic emulation); thus
   601 'proof method scripts' have to be in depth-first order;
   602 
   603 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   604 
   605 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   606 should instead use individual commands for printing items
   607 (print_commands, print_methods etc.);
   608 
   609 * Isar: added 'nothing' --- the empty list of theorems;
   610 
   611 
   612 *** HOL ***
   613 
   614 * HOL/MicroJava: formalization of a fragment of Java, together with a
   615 corresponding virtual machine and a specification of its bytecode
   616 verifier and a lightweight bytecode verifier, including proofs of
   617 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   618 Cornelia Pusch (see also the homepage of project Bali at
   619 http://isabelle.in.tum.de/Bali/);
   620 
   621 * HOL/Algebra: new theory of rings and univariate polynomials, by
   622 Clemens Ballarin;
   623 
   624 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   625 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   626 Rasmussen;
   627 
   628 * HOL/Lattice: fundamental concepts of lattice theory and order
   629 structures, including duals, properties of bounds versus algebraic
   630 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   631 Theorem for complete lattices etc.; may also serve as a demonstration
   632 for abstract algebraic reasoning using axiomatic type classes, and
   633 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   634 
   635 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   636 von Oheimb;
   637 
   638 * HOL/IMPP: extension of IMP with local variables and mutually
   639 recursive procedures, by David von Oheimb;
   640 
   641 * HOL/Lambda: converted into new-style theory and document;
   642 
   643 * HOL/ex/Multiquote: example of multiple nested quotations and
   644 anti-quotations -- basically a generalized version of de-Bruijn
   645 representation; very useful in avoiding lifting of operations;
   646 
   647 * HOL/record: added general record equality rule to simpset; fixed
   648 select-update simplification procedure to handle extended records as
   649 well; admit "r" as field name;
   650 
   651 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   652 other numeric types and also as the identity of groups, rings, etc.;
   653 
   654 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   655 Types nat and int belong to this axclass;
   656 
   657 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   658    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   659    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   660   two terms #m*u and #n*u are replaced by #(m+n)*u
   661     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   662   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   663     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   664 
   665 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   666 powerful prover for predicate logic but knows nothing of clasets; see
   667 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   668 
   669 * HOL: new version of "case_tac" subsumes both boolean case split and
   670 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   671 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   672 
   673 * HOL: simplification no longer dives into case-expressions: only the
   674 selector expression is simplified, but not the remaining arms; to
   675 enable full simplification of case-expressions for datatype t, you may
   676 remove t.weak_case_cong from the simpset, either globally (Delcongs
   677 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   678 
   679 * HOL/recdef: the recursion equations generated by 'recdef' for
   680 function 'f' are now called f.simps instead of f.rules; if all
   681 termination conditions are proved automatically, these simplification
   682 rules are added to the simpset, as in primrec; rules may be named
   683 individually as well, resulting in a separate list of theorems for
   684 each equation;
   685 
   686 * HOL/While is a new theory that provides a while-combinator. It
   687 permits the definition of tail-recursive functions without the
   688 provision of a termination measure. The latter is necessary once the
   689 invariant proof rule for while is applied.
   690 
   691 * HOL: new (overloaded) notation for the set of elements below/above
   692 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   693 
   694 * HOL: theorems impI, allI, ballI bound as "strip";
   695 
   696 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   697 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   698 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   699 
   700 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   701 
   702 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   703 main HOL, but was unused);
   704 
   705 * HOL: fewer consts declared as global (e.g. have to refer to
   706 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   707 
   708 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   709 in case of overlap with user translations (e.g. judgements over
   710 tuples); (note that the underlying logical represenation is still
   711 bogus);
   712 
   713 
   714 *** ZF ***
   715 
   716 * ZF: simplification automatically cancels common terms in arithmetic
   717 expressions over nat and int;
   718 
   719 * ZF: new treatment of nat to minimize type-checking: all operators
   720 coerce their operands to a natural number using the function natify,
   721 making the algebraic laws unconditional;
   722 
   723 * ZF: as above, for int: operators coerce their operands to an integer
   724 using the function intify;
   725 
   726 * ZF: the integer library now contains many of the usual laws for the
   727 orderings, including $<=, and monotonicity laws for $+ and $*;
   728 
   729 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   730 simplification;
   731 
   732 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   733 to the simplifier and classical reasoner simultaneously;
   734 
   735 
   736 *** General ***
   737 
   738 * Provers: blast_tac now handles actual object-logic rules as
   739 assumptions; note that auto_tac uses blast_tac internally as well;
   740 
   741 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   742 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   743 
   744 * Provers: delrules now handles destruct rules as well (no longer need
   745 explicit make_elim);
   746 
   747 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   748   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   749 use instead the strong form,
   750   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   751 in HOL, FOL and ZF the function cla_make_elim will create such rules
   752 from destruct-rules;
   753 
   754 * Provers: Simplifier.easy_setup provides a fast path to basic
   755 Simplifier setup for new object-logics;
   756 
   757 * Pure: AST translation rules no longer require constant head on LHS;
   758 
   759 * Pure: improved name spaces: ambiguous output is qualified; support
   760 for hiding of names;
   761 
   762 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   763 XSYMBOL_HOME; no longer need to do manual configuration in most
   764 situations;
   765 
   766 * system: compression of ML heaps images may now be controlled via -c
   767 option of isabelle and isatool usedir (currently only observed by
   768 Poly/ML);
   769 
   770 * system: isatool installfonts may handle X-Symbol fonts as well (very
   771 useful for remote X11);
   772 
   773 * system: provide TAGS file for Isabelle sources;
   774 
   775 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   776 order;
   777 
   778 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   779 timing flag supersedes proof_timing and Toplevel.trace;
   780 
   781 * ML: new combinators |>> and |>>> for incremental transformations
   782 with secondary results (e.g. certain theory extensions):
   783 
   784 * ML: PureThy.add_defs gets additional argument to indicate potential
   785 overloading (usually false);
   786 
   787 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   788 results;
   789 
   790 
   791 
   792 New in Isabelle99 (October 1999)
   793 --------------------------------
   794 
   795 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   796 
   797 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   798 are no longer simplified.  (This allows the simplifier to unfold recursive
   799 functional programs.)  To restore the old behaviour, declare
   800 
   801     Delcongs [if_weak_cong];
   802 
   803 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   804 complement;
   805 
   806 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   807 
   808 * HOL/datatype: mutual_induct_tac no longer exists --
   809   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   810 
   811 * HOL/typedef: fixed type inference for representing set; type
   812 arguments now have to occur explicitly on the rhs as type constraints;
   813 
   814 * ZF: The con_defs part of an inductive definition may no longer refer
   815 to constants declared in the same theory;
   816 
   817 * HOL, ZF: the function mk_cases, generated by the inductive
   818 definition package, has lost an argument.  To simplify its result, it
   819 uses the default simpset instead of a supplied list of theorems.
   820 
   821 * HOL/List: the constructors of type list are now Nil and Cons;
   822 
   823 * Simplifier: the type of the infix ML functions
   824         setSSolver addSSolver setSolver addSolver
   825 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   826 for packaging solvers. A solver is created via
   827         mk_solver: string -> (thm list -> int -> tactic) -> solver
   828 where the string argument is only a comment.
   829 
   830 
   831 *** Proof tools ***
   832 
   833 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   834 decision procedure for linear arithmetic. Currently it is used for
   835 types `nat', `int', and `real' in HOL (see below); it can, should and
   836 will be instantiated for other types and logics as well.
   837 
   838 * The simplifier now accepts rewrite rules with flexible heads, eg
   839      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   840   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   841   matching.
   842 
   843 
   844 *** General ***
   845 
   846 * New Isabelle/Isar subsystem provides an alternative to traditional
   847 tactical theorem proving; together with the ProofGeneral/isar user
   848 interface it offers an interactive environment for developing human
   849 readable proof documents (Isar == Intelligible semi-automated
   850 reasoning); for further information see isatool doc isar-ref,
   851 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   852 
   853 * improved and simplified presentation of theories: better HTML markup
   854 (including colors), graph views in several sizes; isatool usedir now
   855 provides a proper interface for user theories (via -P option); actual
   856 document preparation based on (PDF)LaTeX is available as well (for
   857 new-style theories only); see isatool doc system for more information;
   858 
   859 * native support for Proof General, both for classic Isabelle and
   860 Isabelle/Isar;
   861 
   862 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   863 using the graph browser tool;
   864 
   865 * Isabelle manuals now also available as PDF;
   866 
   867 * theory loader rewritten from scratch (may not be fully
   868 bug-compatible); old loadpath variable has been replaced by show_path,
   869 add_path, del_path, reset_path functions; new operations such as
   870 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   871 isatool doc ref);
   872 
   873 * improved isatool install: option -k creates KDE application icon,
   874 option -p DIR installs standalone binaries;
   875 
   876 * added ML_PLATFORM setting (useful for cross-platform installations);
   877 more robust handling of platform specific ML images for SML/NJ;
   878 
   879 * the settings environment is now statically scoped, i.e. it is never
   880 created again in sub-processes invoked from isabelle, isatool, or
   881 Isabelle;
   882 
   883 * path element specification '~~' refers to '$ISABELLE_HOME';
   884 
   885 * in locales, the "assumes" and "defines" parts may be omitted if
   886 empty;
   887 
   888 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   889 long arrows);
   890 
   891 * new print_mode "HTML";
   892 
   893 * new flag show_tags controls display of tags of theorems (which are
   894 basically just comments that may be attached by some tools);
   895 
   896 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   897 mode and goal output format:
   898 
   899 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   900 244c244
   901 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   902 ---
   903 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   904 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   905 181c181
   906 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   907 ---
   908 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   909 
   910 * function bind_thms stores lists of theorems (cf. bind_thm);
   911 
   912 * new shorthand tactics ftac, eatac, datac, fatac;
   913 
   914 * qed (and friends) now accept "" as result name; in that case the
   915 theorem is not stored, but proper checks and presentation of the
   916 result still apply;
   917 
   918 * theorem database now also indexes constants "Trueprop", "all",
   919 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   920 
   921 
   922 *** HOL ***
   923 
   924 ** HOL arithmetic **
   925 
   926 * There are now decision procedures for linear arithmetic over nat and
   927 int:
   928 
   929 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   930 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   931 are treated as atomic; subformulae not involving type `nat' or `int'
   932 are ignored; quantified subformulae are ignored unless they are
   933 positive universal or negative existential. The tactic has to be
   934 invoked by hand and can be a little bit slow. In particular, the
   935 running time is exponential in the number of occurrences of `min' and
   936 `max', and `-' on `nat'.
   937 
   938 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   939 (negated) (in)equalities among the premises and the conclusion into
   940 account (i.e. no compound formulae) and does not know about `min' and
   941 `max', and `-' on `nat'. It is fast and is used automatically by the
   942 simplifier.
   943 
   944 NB: At the moment, these decision procedures do not cope with mixed
   945 nat/int formulae where the two parts interact, such as `m < n ==>
   946 int(m) < int(n)'.
   947 
   948 * HOL/Numeral provides a generic theory of numerals (encoded
   949 efficiently as bit strings); setup for types nat/int/real is in place;
   950 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   951 int, existing theories and proof scripts may require a few additional
   952 type constraints;
   953 
   954 * integer division and remainder can now be performed on constant
   955 arguments;
   956 
   957 * many properties of integer multiplication, division and remainder
   958 are now available;
   959 
   960 * An interface to the Stanford Validity Checker (SVC) is available through the
   961 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   962 are proved automatically.  SVC must be installed separately, and its results
   963 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   964 invocation of the underlying oracle).  For SVC see
   965   http://verify.stanford.edu/SVC
   966 
   967 * IsaMakefile: the HOL-Real target now builds an actual image;
   968 
   969 
   970 ** HOL misc **
   971 
   972 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   973 (in Isabelle/Isar) -- by Gertrud Bauer;
   974 
   975 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   976 analysis for assembly languages with subtypes;
   977 
   978 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   979 -- avoids syntactic ambiguities and treats state, transition, and
   980 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   981 changed syntax and (many) tactics;
   982 
   983 * HOL/inductive: Now also handles more general introduction rules such
   984   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   985   theorems are now maintained within the theory (maintained via the
   986   "mono" attribute);
   987 
   988 * HOL/datatype: Now also handles arbitrarily branching datatypes
   989   (using function types) such as
   990 
   991   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   992 
   993 * HOL/record: record_simproc (part of the default simpset) takes care
   994 of selectors applied to updated records; record_split_tac is no longer
   995 part of the default claset; update_defs may now be removed from the
   996 simpset in many cases; COMPATIBILITY: old behavior achieved by
   997 
   998   claset_ref () := claset() addSWrapper record_split_wrapper;
   999   Delsimprocs [record_simproc]
  1000 
  1001 * HOL/typedef: fixed type inference for representing set; type
  1002 arguments now have to occur explicitly on the rhs as type constraints;
  1003 
  1004 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1005 names rather than an ML expression;
  1006 
  1007 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1008 supplied later.  Program schemes can be defined, such as
  1009     "While B C s = (if B s then While B C (C s) else s)"
  1010 where the well-founded relation can be chosen after B and C have been given.
  1011 
  1012 * HOL/List: the constructors of type list are now Nil and Cons;
  1013 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1014 course, ML tools referring to List.list.op # etc. have to be adapted;
  1015 
  1016 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1017 disabled by default; run isabelle with option -m HOL to get back to
  1018 the original Gordon/HOL-style output;
  1019 
  1020 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1021 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1022 
  1023 * HOL basic syntax simplified (more orthogonal): all variants of
  1024 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1025 Eps operator is provided as well: "SOME x. P[x]";
  1026 
  1027 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1028 
  1029 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1030 thus available for user theories;
  1031 
  1032 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1033 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1034 time;
  1035 
  1036 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1037 several times and then mp;
  1038 
  1039 
  1040 *** LK ***
  1041 
  1042 * the notation <<...>> is now available as a notation for sequences of
  1043 formulas;
  1044 
  1045 * the simplifier is now installed
  1046 
  1047 * the axiom system has been generalized (thanks to Soren Heilmann)
  1048 
  1049 * the classical reasoner now has a default rule database
  1050 
  1051 
  1052 *** ZF ***
  1053 
  1054 * new primrec section allows primitive recursive functions to be given
  1055 directly (as in HOL) over datatypes and the natural numbers;
  1056 
  1057 * new tactics induct_tac and exhaust_tac for induction (or case
  1058 analysis) over datatypes and the natural numbers;
  1059 
  1060 * the datatype declaration of type T now defines the recursor T_rec;
  1061 
  1062 * simplification automatically does freeness reasoning for datatype
  1063 constructors;
  1064 
  1065 * automatic type-inference, with AddTCs command to insert new
  1066 type-checking rules;
  1067 
  1068 * datatype introduction rules are now added as Safe Introduction rules
  1069 to the claset;
  1070 
  1071 * the syntax "if P then x else y" is now available in addition to
  1072 if(P,x,y);
  1073 
  1074 
  1075 *** Internal programming interfaces ***
  1076 
  1077 * tuned simplifier trace output; new flag debug_simp;
  1078 
  1079 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1080 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1081 
  1082 * AxClass.axclass_tac lost the theory argument;
  1083 
  1084 * tuned current_goals_markers semantics: begin / end goal avoids
  1085 printing empty lines;
  1086 
  1087 * removed prs and prs_fn hook, which was broken because it did not
  1088 include \n in its semantics, forcing writeln to add one
  1089 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1090 string -> unit if you really want to output text without newline;
  1091 
  1092 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1093 plain output, interface builders may have to enable 'isabelle_font'
  1094 mode to get Isabelle font glyphs as before;
  1095 
  1096 * refined token_translation interface; INCOMPATIBILITY: output length
  1097 now of type real instead of int;
  1098 
  1099 * theory loader actions may be traced via new ThyInfo.add_hook
  1100 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1101 your own database of information attached to *whole* theories -- as
  1102 opposed to intra-theory data slots offered via TheoryDataFun;
  1103 
  1104 * proper handling of dangling sort hypotheses (at last!);
  1105 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1106 extra sort hypotheses that can be witnessed from the type signature;
  1107 the force_strip_shyps flag is gone, any remaining shyps are simply
  1108 left in the theorem (with a warning issued by strip_shyps_warning);
  1109 
  1110 
  1111 
  1112 New in Isabelle98-1 (October 1998)
  1113 ----------------------------------
  1114 
  1115 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1116 
  1117 * several changes of automated proof tools;
  1118 
  1119 * HOL: major changes to the inductive and datatype packages, including
  1120 some minor incompatibilities of theory syntax;
  1121 
  1122 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1123 called `inj_on';
  1124 
  1125 * HOL: removed duplicate thms in Arith:
  1126   less_imp_add_less  should be replaced by  trans_less_add1
  1127   le_imp_add_le      should be replaced by  trans_le_add1
  1128 
  1129 * HOL: unary minus is now overloaded (new type constraints may be
  1130 required);
  1131 
  1132 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1133 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1134 now taken as an integer constant.
  1135 
  1136 * Pure: ML function 'theory_of' renamed to 'theory';
  1137 
  1138 
  1139 *** Proof tools ***
  1140 
  1141 * Simplifier:
  1142   1. Asm_full_simp_tac is now more aggressive.
  1143      1. It will sometimes reorient premises if that increases their power to
  1144         simplify.
  1145      2. It does no longer proceed strictly from left to right but may also
  1146         rotate premises to achieve further simplification.
  1147      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1148      old Asm_full_simp_tac in that it does not rotate premises.
  1149   2. The simplifier now knows a little bit about nat-arithmetic.
  1150 
  1151 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1152 allows for selected deletion of wrappers, by introduction of names for
  1153 wrapper functionals.  This implies that addbefore, addSbefore,
  1154 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1155 and that adding two tactics with the same name overwrites the first
  1156 one (emitting a warning).
  1157   type wrapper = (int -> tactic) -> (int -> tactic)
  1158   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1159   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1160   delWrapper, delSWrapper: claset *  string            -> claset
  1161   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1162 
  1163 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1164 semantics; addbefore now affects only the unsafe part of step_tac
  1165 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1166 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1167 by Force_tac;
  1168 
  1169 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1170 compWrapper; added safe wrapper (and access functions for it);
  1171 
  1172 * HOL/split_all_tac is now much faster and fails if there is nothing
  1173 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1174 and the names of the automatically generated variables have changed.
  1175 split_all_tac has moved within claset() from unsafe wrappers to safe
  1176 wrappers, which means that !!-bound variables are split much more
  1177 aggressively, and safe_tac and clarify_tac now split such variables.
  1178 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1179 Note: the same holds for record_split_tac, which does the job of
  1180 split_all_tac for record fields.
  1181 
  1182 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1183 permanently to the default simpset using Addsplits just like
  1184 Addsimps. They can be removed via Delsplits just like
  1185 Delsimps. Lower-case versions are also available.
  1186 
  1187 * HOL/Simplifier: The rule split_if is now part of the default
  1188 simpset. This means that the simplifier will eliminate all occurrences
  1189 of if-then-else in the conclusion of a goal. To prevent this, you can
  1190 either remove split_if completely from the default simpset by
  1191 `Delsplits [split_if]' or remove it in a specific call of the
  1192 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1193 other case splitting rules to/from the default simpset: every datatype
  1194 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1195 t is the name of the datatype).
  1196 
  1197 * Classical reasoner / Simplifier combination: new force_tac (and
  1198 derivatives Force_tac, force) combines rewriting and classical
  1199 reasoning (and whatever other tools) similarly to auto_tac, but is
  1200 aimed to solve the given subgoal completely.
  1201 
  1202 
  1203 *** General ***
  1204 
  1205 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1206 and `goalw': the theory is no longer needed as an explicit argument -
  1207 the current theory context is used; assumptions are no longer returned
  1208 at the ML-level unless one of them starts with ==> or !!; it is
  1209 recommended to convert to these new commands using isatool fixgoal
  1210 (backup your sources first!);
  1211 
  1212 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1213 the current theory context, and 'theory' to lookup stored theories;
  1214 
  1215 * new theory section 'locale' for declaring constants, assumptions and
  1216 definitions that have local scope;
  1217 
  1218 * new theory section 'nonterminals' for purely syntactic types;
  1219 
  1220 * new theory section 'setup' for generic ML setup functions
  1221 (e.g. package initialization);
  1222 
  1223 * the distribution now includes Isabelle icons: see
  1224 lib/logo/isabelle-{small,tiny}.xpm;
  1225 
  1226 * isatool install - install binaries with absolute references to
  1227 ISABELLE_HOME/bin;
  1228 
  1229 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1230 
  1231 * print mode 'emacs' reserved for Isamode;
  1232 
  1233 * support multiple print (ast) translations per constant name;
  1234 
  1235 * theorems involving oracles are now printed with a suffixed [!];
  1236 
  1237 
  1238 *** HOL ***
  1239 
  1240 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1241 
  1242 * HOL/inductive package reorganized and improved: now supports mutual
  1243 definitions such as
  1244 
  1245   inductive EVEN ODD
  1246     intrs
  1247       null "0 : EVEN"
  1248       oddI "n : EVEN ==> Suc n : ODD"
  1249       evenI "n : ODD ==> Suc n : EVEN"
  1250 
  1251 new theorem list "elims" contains an elimination rule for each of the
  1252 recursive sets; inductive definitions now handle disjunctive premises
  1253 correctly (also ZF);
  1254 
  1255 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1256 "mutual_induct" no longer exists - the induction rule is always
  1257 contained in "induct";
  1258 
  1259 
  1260 * HOL/datatype package re-implemented and greatly improved: now
  1261 supports mutually recursive datatypes such as
  1262 
  1263   datatype
  1264     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1265             | SUM ('a aexp) ('a aexp)
  1266             | DIFF ('a aexp) ('a aexp)
  1267             | NUM 'a
  1268   and
  1269     'a bexp = LESS ('a aexp) ('a aexp)
  1270             | AND ('a bexp) ('a bexp)
  1271             | OR ('a bexp) ('a bexp)
  1272 
  1273 as well as indirectly recursive datatypes such as
  1274 
  1275   datatype
  1276     ('a, 'b) term = Var 'a
  1277                   | App 'b ((('a, 'b) term) list)
  1278 
  1279 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1280 induction on mutually / indirectly recursive datatypes.
  1281 
  1282 Primrec equations are now stored in theory and can be accessed via
  1283 <function_name>.simps.
  1284 
  1285 INCOMPATIBILITIES:
  1286 
  1287   - Theories using datatypes must now have theory Datatype as an
  1288     ancestor.
  1289   - The specific <typename>.induct_tac no longer exists - use the
  1290     generic induct_tac instead.
  1291   - natE has been renamed to nat.exhaust - use exhaust_tac
  1292     instead of res_inst_tac ... natE. Note that the variable
  1293     names in nat.exhaust differ from the names in natE, this
  1294     may cause some "fragile" proofs to fail.
  1295   - The theorems split_<typename>_case and split_<typename>_case_asm
  1296     have been renamed to <typename>.split and <typename>.split_asm.
  1297   - Since default sorts of type variables are now handled correctly,
  1298     some datatype definitions may have to be annotated with explicit
  1299     sort constraints.
  1300   - Primrec definitions no longer require function name and type
  1301     of recursive argument.
  1302 
  1303 Consider using isatool fixdatatype to adapt your theories and proof
  1304 scripts to the new package (backup your sources first!).
  1305 
  1306 
  1307 * HOL/record package: considerably improved implementation; now
  1308 includes concrete syntax for record types, terms, updates; theorems
  1309 for surjective pairing and splitting !!-bound record variables; proof
  1310 support is as follows:
  1311 
  1312   1) standard conversions (selectors or updates applied to record
  1313 constructor terms) are part of the standard simpset;
  1314 
  1315   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1316 made part of standard simpset and claset via addIffs;
  1317 
  1318   3) a tactic for record field splitting (record_split_tac) is part of
  1319 the standard claset (addSWrapper);
  1320 
  1321 To get a better idea about these rules you may retrieve them via
  1322 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1323 the name of your record type.
  1324 
  1325 The split tactic 3) conceptually simplifies by the following rule:
  1326 
  1327   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1328 
  1329 Thus any record variable that is bound by meta-all will automatically
  1330 blow up into some record constructor term, consequently the
  1331 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1332 solve record problems automatically.
  1333 
  1334 
  1335 * reorganized the main HOL image: HOL/Integ and String loaded by
  1336 default; theory Main includes everything;
  1337 
  1338 * automatic simplification of integer sums and comparisons, using cancellation;
  1339 
  1340 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1341 
  1342 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1343 
  1344 * many new identities for unions, intersections, set difference, etc.;
  1345 
  1346 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1347 called split_if, split_split, split_sum_case and split_nat_case (to go
  1348 with add/delsplits);
  1349 
  1350 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1351 (?x::unit) = (); this is made part of the default simpset, which COULD
  1352 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1353 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1354 unit_abs_eta_conv is added in order to counter the effect of
  1355 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1356 %u.f();
  1357 
  1358 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1359 makes more sense);
  1360 
  1361 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1362   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1363   disjointness reasoning but breaking a few old proofs.
  1364 
  1365 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1366 to 'converse' from 'inverse' (for compatibility with ZF and some
  1367 literature);
  1368 
  1369 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1370 the well-founded relation;
  1371 
  1372 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1373     Compl A.  The "Compl" syntax remains available as input syntax for this
  1374     release ONLY.
  1375 
  1376 * HOL/Update: new theory of function updates:
  1377     f(a:=b) == %x. if x=a then b else f x
  1378 may also be iterated as in f(a:=b,c:=d,...);
  1379 
  1380 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1381 
  1382 * HOL/List:
  1383   - new function list_update written xs[i:=v] that updates the i-th
  1384     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1385   - new function `upt' written [i..j(] which generates the list
  1386     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1387     bound write [i..j], which is a shorthand for [i..j+1(].
  1388   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1389 
  1390 * HOL/Arith:
  1391   - removed 'pred' (predecessor) function;
  1392   - generalized some theorems about n-1;
  1393   - many new laws about "div" and "mod";
  1394   - new laws about greatest common divisors (see theory ex/Primes);
  1395 
  1396 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1397 instead of "inverse";
  1398 
  1399 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1400   of the multiset ordering;
  1401 
  1402 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1403   (not included by default);
  1404 
  1405 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1406 
  1407 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1408   programs, i.e. different program variables may have different types.
  1409 
  1410 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1411   [previously, this check worked only if the rewrite rule was unconditional]
  1412   Now rew can involve either definitions or equalities (either == or =).
  1413 
  1414 
  1415 *** ZF ***
  1416 
  1417 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1418   only the theorems proved on ZF.ML;
  1419 
  1420 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1421   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1422   disjointness reasoning but breaking a few old proofs.
  1423 
  1424 * ZF/Update: new theory of function updates
  1425     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1426   may also be iterated as in f(a:=b,c:=d,...);
  1427 
  1428 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1429 
  1430 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1431   [previously, this check worked only if the rewrite rule was unconditional]
  1432   Now rew can involve either definitions or equalities (either == or =).
  1433 
  1434 * case_tac provided for compatibility with HOL
  1435     (like the old excluded_middle_tac, but with subgoals swapped)
  1436 
  1437 
  1438 *** Internal programming interfaces ***
  1439 
  1440 * Pure: several new basic modules made available for general use, see
  1441 also src/Pure/README;
  1442 
  1443 * improved the theory data mechanism to support encapsulation (data
  1444 kind name replaced by private Object.kind, acting as authorization
  1445 key); new type-safe user interface via functor TheoryDataFun; generic
  1446 print_data function becomes basically useless;
  1447 
  1448 * removed global_names compatibility flag -- all theory declarations
  1449 are qualified by default;
  1450 
  1451 * module Pure/Syntax now offers quote / antiquote translation
  1452 functions (useful for Hoare logic etc. with implicit dependencies);
  1453 see HOL/ex/Antiquote for an example use;
  1454 
  1455 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1456 cterm -> thm;
  1457 
  1458 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1459 subgoal;
  1460 
  1461 * Display.print_goals function moved to Locale.print_goals;
  1462 
  1463 * standard print function for goals supports current_goals_markers
  1464 variable for marking begin of proof, end of proof, start of goal; the
  1465 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1466 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1467 for example;
  1468 
  1469 
  1470 
  1471 New in Isabelle98 (January 1998)
  1472 --------------------------------
  1473 
  1474 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1475 
  1476 * changed lexical syntax of terms / types: dots made part of long
  1477 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1478 
  1479 * simpset (and claset) reference variable replaced by functions
  1480 simpset / simpset_ref;
  1481 
  1482 * no longer supports theory aliases (via merge) and non-trivial
  1483 implicit merge of thms' signatures;
  1484 
  1485 * most internal names of constants changed due to qualified names;
  1486 
  1487 * changed Pure/Sequence interface (see Pure/seq.ML);
  1488 
  1489 
  1490 *** General Changes ***
  1491 
  1492 * hierachically structured name spaces (for consts, types, axms, thms
  1493 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1494 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1495 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1496 long_names for fully qualified output names; NOTE: ML programs
  1497 (special tactics, packages etc.) referring to internal names may have
  1498 to be adapted to cope with fully qualified names; in case of severe
  1499 backward campatibility problems try setting 'global_names' at compile
  1500 time to have enrything declared within a flat name space; one may also
  1501 fine tune name declarations in theories via the 'global' and 'local'
  1502 section;
  1503 
  1504 * reimplemented the implicit simpset and claset using the new anytype
  1505 data filed in signatures; references simpset:simpset ref etc. are
  1506 replaced by functions simpset:unit->simpset and
  1507 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1508 to patch your ML files accordingly;
  1509 
  1510 * HTML output now includes theory graph data for display with Java
  1511 applet or isatool browser; data generated automatically via isatool
  1512 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1513 
  1514 * defs may now be conditional; improved rewrite_goals_tac to handle
  1515 conditional equations;
  1516 
  1517 * defs now admits additional type arguments, using TYPE('a) syntax;
  1518 
  1519 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1520 creates a new theory node; implicit merge of thms' signatures is
  1521 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1522 transfer:theory->thm->thm in (rare) cases;
  1523 
  1524 * improved handling of draft signatures / theories; draft thms (and
  1525 ctyps, cterms) are automatically promoted to real ones;
  1526 
  1527 * slightly changed interfaces for oracles: admit many per theory, named
  1528 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1529 
  1530 * print_goals: optional output of const types (set show_consts and
  1531 show_types);
  1532 
  1533 * improved output of warnings (###) and errors (***);
  1534 
  1535 * subgoal_tac displays a warning if the new subgoal has type variables;
  1536 
  1537 * removed old README and Makefiles;
  1538 
  1539 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1540 
  1541 * removed obsolete init_pps and init_database;
  1542 
  1543 * deleted the obsolete tactical STATE, which was declared by
  1544     fun STATE tacfun st = tacfun st st;
  1545 
  1546 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1547 (which abbreviates $HOME);
  1548 
  1549 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1550 use isatool fixseq to adapt your ML programs (this works for fully
  1551 qualified references to the Sequence structure only!);
  1552 
  1553 * use_thy no longer requires writable current directory; it always
  1554 reloads .ML *and* .thy file, if either one is out of date;
  1555 
  1556 
  1557 *** Classical Reasoner ***
  1558 
  1559 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1560 tactics that use classical reasoning to simplify a subgoal without
  1561 splitting it into several subgoals;
  1562 
  1563 * Safe_tac: like safe_tac but uses the default claset;
  1564 
  1565 
  1566 *** Simplifier ***
  1567 
  1568 * added simplification meta rules:
  1569     (asm_)(full_)simplify: simpset -> thm -> thm;
  1570 
  1571 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1572 logics (again);
  1573 
  1574 * added prems argument to simplification procedures;
  1575 
  1576 * HOL, FOL, ZF: added infix function `addsplits':
  1577   instead of `<simpset> setloop (split_tac <thms>)'
  1578   you can simply write `<simpset> addsplits <thms>'
  1579 
  1580 
  1581 *** Syntax ***
  1582 
  1583 * TYPE('a) syntax for type reflection terms;
  1584 
  1585 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1586 
  1587 * pretty printer: changed order of mixfix annotation preference (again!);
  1588 
  1589 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1590 
  1591 
  1592 *** HOL ***
  1593 
  1594 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1595   with `addloop' of the simplifier to faciliate case splitting in premises.
  1596 
  1597 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1598 
  1599 * HOL/Auth: new protocol proofs including some for the Internet
  1600   protocol TLS;
  1601 
  1602 * HOL/Map: new theory of `maps' a la VDM;
  1603 
  1604 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1605 cancelling out common nat summands from =, <, <= (in)equalities, or
  1606 differences; simplification procedures nat_cancel_factor for
  1607 cancelling common factor from =, <, <= (in)equalities over natural
  1608 sums; nat_cancel contains both kinds of procedures, it is installed by
  1609 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1610 
  1611 * HOL/simplifier: terms of the form
  1612   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1613   are rewritten to
  1614   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1615   and those of the form
  1616   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1617   are rewritten to
  1618   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1619 
  1620 * HOL/datatype
  1621   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1622 
  1623   P(t_case f1 ... fn x) =
  1624      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1625         ...
  1626        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1627      )
  1628 
  1629   and a theorem `split_t_case_asm' of the form
  1630 
  1631   P(t_case f1 ... fn x) =
  1632     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1633         ...
  1634        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1635      )
  1636   which can be added to a simpset via `addsplits'. The existing theorems
  1637   expand_list_case and expand_option_case have been renamed to
  1638   split_list_case and split_option_case.
  1639 
  1640 * HOL/Arithmetic:
  1641   - `pred n' is automatically converted to `n-1'.
  1642     Users are strongly encouraged not to use `pred' any longer,
  1643     because it will disappear altogether at some point.
  1644   - Users are strongly encouraged to write "0 < n" rather than
  1645     "n ~= 0". Theorems and proof tools have been modified towards this
  1646     `standard'.
  1647 
  1648 * HOL/Lists:
  1649   the function "set_of_list" has been renamed "set" (and its theorems too);
  1650   the function "nth" now takes its arguments in the reverse order and
  1651   has acquired the infix notation "!" as in "xs!n".
  1652 
  1653 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1654 
  1655 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1656   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1657 
  1658 * HOL/record: extensible records with schematic structural subtyping
  1659 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1660 still lacks various theorems and concrete record syntax;
  1661 
  1662 
  1663 *** HOLCF ***
  1664 
  1665 * removed "axioms" and "generated by" sections;
  1666 
  1667 * replaced "ops" section by extended "consts" section, which is capable of
  1668   handling the continuous function space "->" directly;
  1669 
  1670 * domain package:
  1671   . proves theorems immediately and stores them in the theory,
  1672   . creates hierachical name space,
  1673   . now uses normal mixfix annotations (instead of cinfix...),
  1674   . minor changes to some names and values (for consistency),
  1675   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1676   . separator between mutual domain defs: changed "," to "and",
  1677   . improved handling of sort constraints;  now they have to
  1678     appear on the left-hand side of the equations only;
  1679 
  1680 * fixed LAM <x,y,zs>.b syntax;
  1681 
  1682 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1683 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1684 
  1685 
  1686 *** FOL and ZF ***
  1687 
  1688 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1689   with `addloop' of the simplifier to faciliate case splitting in premises.
  1690 
  1691 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1692 in HOL, they strip ALL and --> from proved theorems;
  1693 
  1694 
  1695 
  1696 New in Isabelle94-8 (May 1997)
  1697 ------------------------------
  1698 
  1699 *** General Changes ***
  1700 
  1701 * new utilities to build / run / maintain Isabelle etc. (in parts
  1702 still somewhat experimental); old Makefiles etc. still functional;
  1703 
  1704 * new 'Isabelle System Manual';
  1705 
  1706 * INSTALL text, together with ./configure and ./build scripts;
  1707 
  1708 * reimplemented type inference for greater efficiency, better error
  1709 messages and clean internal interface;
  1710 
  1711 * prlim command for dealing with lots of subgoals (an easier way of
  1712 setting goals_limit);
  1713 
  1714 
  1715 *** Syntax ***
  1716 
  1717 * supports alternative (named) syntax tables (parser and pretty
  1718 printer); internal interface is provided by add_modesyntax(_i);
  1719 
  1720 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1721 be used in conjunction with the Isabelle symbol font; uses the
  1722 "symbols" syntax table;
  1723 
  1724 * added token_translation interface (may translate name tokens in
  1725 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1726 the current print_mode); IMPORTANT: user print translation functions
  1727 are responsible for marking newly introduced bounds
  1728 (Syntax.mark_boundT);
  1729 
  1730 * token translations for modes "xterm" and "xterm_color" that display
  1731 names in bold, underline etc. or colors (which requires a color
  1732 version of xterm);
  1733 
  1734 * infixes may now be declared with names independent of their syntax;
  1735 
  1736 * added typed_print_translation (like print_translation, but may
  1737 access type of constant);
  1738 
  1739 
  1740 *** Classical Reasoner ***
  1741 
  1742 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1743 some limitations.  Blast_tac...
  1744   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1745   + ignores elimination rules that don't have the correct format
  1746         (the conclusion MUST be a formula variable)
  1747   + ignores types, which can make HOL proofs fail
  1748   + rules must not require higher-order unification, e.g. apply_type in ZF
  1749     [message "Function Var's argument not a bound variable" relates to this]
  1750   + its proof strategy is more general but can actually be slower
  1751 
  1752 * substitution with equality assumptions no longer permutes other
  1753 assumptions;
  1754 
  1755 * minor changes in semantics of addafter (now called addaltern); renamed
  1756 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1757 (and access functions for it);
  1758 
  1759 * improved combination of classical reasoner and simplifier:
  1760   + functions for handling clasimpsets
  1761   + improvement of addss: now the simplifier is called _after_ the
  1762     safe steps.
  1763   + safe variant of addss called addSss: uses safe simplifications
  1764     _during_ the safe steps. It is more complete as it allows multiple
  1765     instantiations of unknowns (e.g. with slow_tac).
  1766 
  1767 *** Simplifier ***
  1768 
  1769 * added interface for simplification procedures (functions that
  1770 produce *proven* rewrite rules on the fly, depending on current
  1771 redex);
  1772 
  1773 * ordering on terms as parameter (used for ordered rewriting);
  1774 
  1775 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1776 
  1777 * the solver is now split into a safe and an unsafe part.
  1778 This should be invisible for the normal user, except that the
  1779 functions setsolver and addsolver have been renamed to setSolver and
  1780 addSolver; added safe_asm_full_simp_tac;
  1781 
  1782 
  1783 *** HOL ***
  1784 
  1785 * a generic induction tactic `induct_tac' which works for all datatypes and
  1786 also for type `nat';
  1787 
  1788 * a generic case distinction tactic `exhaust_tac' which works for all
  1789 datatypes and also for type `nat';
  1790 
  1791 * each datatype comes with a function `size';
  1792 
  1793 * patterns in case expressions allow tuple patterns as arguments to
  1794 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1795 
  1796 * primrec now also works with type nat;
  1797 
  1798 * recdef: a new declaration form, allows general recursive functions to be
  1799 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1800 
  1801 * the constant for negation has been renamed from "not" to "Not" to
  1802 harmonize with FOL, ZF, LK, etc.;
  1803 
  1804 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1805 infinite lists;
  1806 
  1807 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1808 
  1809 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1810 problems in commutative rings, using axiomatic type classes for + and *;
  1811 
  1812 * more examples in HOL/MiniML and HOL/Auth;
  1813 
  1814 * more default rewrite rules for quantifiers, union/intersection;
  1815 
  1816 * a new constant `arbitrary == @x.False';
  1817 
  1818 * HOLCF/IOA replaces old HOL/IOA;
  1819 
  1820 * HOLCF changes: derived all rules and arities
  1821   + axiomatic type classes instead of classes
  1822   + typedef instead of faking type definitions
  1823   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1824   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1825   + eliminated the types void, one, tr
  1826   + use unit lift and bool lift (with translations) instead of one and tr
  1827   + eliminated blift from Lift3.thy (use Def instead of blift)
  1828   all eliminated rules are derived as theorems --> no visible changes ;
  1829 
  1830 
  1831 *** ZF ***
  1832 
  1833 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1834 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1835 as ZF_cs addSIs [equalityI];
  1836 
  1837 
  1838 
  1839 New in Isabelle94-7 (November 96)
  1840 ---------------------------------
  1841 
  1842 * allowing negative levels (as offsets) in prlev and choplev;
  1843 
  1844 * super-linear speedup for large simplifications;
  1845 
  1846 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1847 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1848 FAIL); can suppress it using the command Delsimps (ex_simps @
  1849 all_simps); De Morgan laws are also now included, by default;
  1850 
  1851 * improved printing of ==>  :  ~:
  1852 
  1853 * new object-logic "Sequents" adds linear logic, while replacing LK
  1854 and Modal (thanks to Sara Kalvala);
  1855 
  1856 * HOL/Auth: correctness proofs for authentication protocols;
  1857 
  1858 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1859 examples on HOL/Auth);
  1860 
  1861 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1862 the rewriter and classical reasoner simultaneously;
  1863 
  1864 * function uresult no longer returns theorems in "standard" format;
  1865 regain previous version by: val uresult = standard o uresult;
  1866 
  1867 
  1868 
  1869 New in Isabelle94-6
  1870 -------------------
  1871 
  1872 * oracles -- these establish an interface between Isabelle and trusted
  1873 external reasoners, which may deliver results as theorems;
  1874 
  1875 * proof objects (in particular record all uses of oracles);
  1876 
  1877 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1878 
  1879 * "constdefs" section in theory files;
  1880 
  1881 * "primrec" section (HOL) no longer requires names;
  1882 
  1883 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1884 
  1885 
  1886 
  1887 New in Isabelle94-5
  1888 -------------------
  1889 
  1890 * reduced space requirements;
  1891 
  1892 * automatic HTML generation from theories;
  1893 
  1894 * theory files no longer require "..." (quotes) around most types;
  1895 
  1896 * new examples, including two proofs of the Church-Rosser theorem;
  1897 
  1898 * non-curried (1994) version of HOL is no longer distributed;
  1899 
  1900 
  1901 
  1902 New in Isabelle94-4
  1903 -------------------
  1904 
  1905 * greatly reduced space requirements;
  1906 
  1907 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1908 
  1909 * searchable theorem database (see the section "Retrieving theorems" on
  1910 page 8 of the Reference Manual);
  1911 
  1912 * new examples, including Grabczewski's monumental case study of the
  1913 Axiom of Choice;
  1914 
  1915 * The previous version of HOL renamed to Old_HOL;
  1916 
  1917 * The new version of HOL (previously called CHOL) uses a curried syntax
  1918 for functions.  Application looks like f a b instead of f(a,b);
  1919 
  1920 * Mutually recursive inductive definitions finally work in HOL;
  1921 
  1922 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1923 translates to the operator "split";
  1924 
  1925 
  1926 
  1927 New in Isabelle94-3
  1928 -------------------
  1929 
  1930 * new infix operator, addss, allowing the classical reasoner to
  1931 perform simplification at each step of its search.  Example:
  1932         fast_tac (cs addss ss)
  1933 
  1934 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1935 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1936 look like (a,b) instead of <a,b>;
  1937 
  1938 * PLEASE NOTE: CHOL will eventually replace HOL!
  1939 
  1940 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1941 It translates to the operator "split".  A new theory of integers is available;
  1942 
  1943 * In ZF, integer numerals now denote two's-complement binary integers.
  1944 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1945 
  1946 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1947 of the Axiom of Choice;
  1948 
  1949 
  1950 
  1951 New in Isabelle94-2
  1952 -------------------
  1953 
  1954 * Significantly faster resolution;
  1955 
  1956 * the different sections in a .thy file can now be mixed and repeated
  1957 freely;
  1958 
  1959 * Database of theorems for FOL, HOL and ZF.  New
  1960 commands including qed, qed_goal and bind_thm store theorems in the database.
  1961 
  1962 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1963 a given theory (thms_of), or find out what theory a theorem was proved in
  1964 (theory_of_thm);
  1965 
  1966 * Bugs fixed in the inductive definition and datatype packages;
  1967 
  1968 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1969 and HOL_dup_cs obsolete;
  1970 
  1971 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1972 have been removed;
  1973 
  1974 * Simpler definition of function space in ZF;
  1975 
  1976 * new results about cardinal and ordinal arithmetic in ZF;
  1977 
  1978 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1979 types;
  1980 
  1981 
  1982 $Id$