NEWS
author wenzelm
Thu Nov 08 23:52:56 2001 +0100 (2001-11-08)
changeset 12106 4a8558dbb6a0
parent 12078 4eb8061286e5
child 12159 b3a708ddedf8
permissions -rw-r--r--
* Isar/Pure: emulation of instantiation tactics (rule_tac, cut_tac,
etc.) now consider the syntactic context of assumptions, giving a
better chance to get type-inference of the arguments right (this is
especially important for locales);
* system: refrain from any attempt at filtering input streams; no
longer support ``8bit'' encoding of old isabelle font, instead proper
iso-latin characters may now be used;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol;
    31 
    32 
    33 *** Isar ***
    34 
    35 * improved proof by cases and induction:
    36   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    37   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    38   - moved induct/cases attributes to Pure, methods to Provers;
    39   - generic method setup instantiated for FOL and HOL;
    40 
    41   - 'case' command admits impromptu naming of parameters (such as
    42 "case (Suc n)");
    43 
    44   - 'induct' method divinates rule instantiation from the inductive
    45 claim; no longer requires excessive ?P bindings for proper
    46 instantiation of cases;
    47 
    48   - 'induct' method properly enumerates all possibilities of set/type
    49 rules; as a consequence facts may be also passed through *type* rules
    50 without further ado;
    51 
    52   - 'induct' method now derives symbolic cases from the *rulified*
    53 rule (before it used to rulify cases stemming from the internal
    54 atomized version); this means that the context of a non-atomic
    55 statement becomes is included in the hypothesis, avoiding the slightly
    56 cumbersome show "PROP ?case" form;
    57 
    58   - 'induct' may now use elim-style induction rules without chaining
    59 facts, using ``missing'' premises from the goal state; this allows
    60 rules stemming from inductive sets to be applied in unstructured
    61 scripts, while still benefitting from proper handling of non-atomic
    62 statements; NB: major inductive premises need to be put first, all the
    63 rest of the goal is passed through the induction;
    64 
    65 * Pure: proper integration with ``locales''; unlike the original
    66 version by Florian Kammueller, Isar locales package high-level proof
    67 contexts rather than raw logical ones (e.g. we admit to include
    68 attributes everywhere);
    69 
    70 * Pure: theory goals now support ad-hoc contexts, which are discharged
    71 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    72 coincides with that of a locale body;
    73 
    74 * Pure: renamed "antecedent" case to "rule_context";
    75 
    76 * Pure: added 'corollary' command;
    77 
    78 * Pure: fixed 'token_translation' command;
    79 
    80 * Pure: removed obsolete 'exported' attribute;
    81 
    82 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    83 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    84 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    85 
    86 * Pure: method 'atomize' presents local goal premises as object-level
    87 statements (atomic meta-level propositions); setup controlled via
    88 rewrite rules declarations of 'atomize' attribute; example
    89 application: 'induct' method with proper rule statements in improper
    90 proof *scripts*;
    91 
    92 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
    93 now consider the syntactic context of assumptions, giving a better
    94 chance to get type-inference of the arguments right (this is
    95 especially important for locales);
    96 
    97 * Provers: 'simplified' attribute may refer to explicit rules instead
    98 of full simplifier context; 'iff' attribute handles conditional rules;
    99 
   100 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   101 
   102 * HOL: 'recdef' now fails on unfinished automated proofs, use
   103 "(permissive)" option to recover old behavior;
   104 
   105 * HOL: 'inductive' no longer features separate (collective) attributes
   106 for 'intros' (was found too confusing);
   107 
   108 
   109 
   110 *** HOL ***
   111 
   112 * HOL: moved over to sane numeral syntax; the new policy is as
   113 follows:
   114 
   115   - 0 and 1 are polymorphic constants, which are defined on any
   116   numeric type (nat, int, real etc.);
   117 
   118   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   119   binary representation internally;
   120 
   121   - type nat has special constructor Suc, and generally prefers Suc 0
   122   over 1::nat and Suc (Suc 0) over 2::nat;
   123 
   124 This change may cause significant INCOMPATIBILITIES; here are some
   125 hints on converting existing sources:
   126 
   127   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   128   entities, so expressions involving "-" (unary or binary minus) need
   129   to be spaced properly;
   130 
   131   - existing occurrences of "1" may need to be constraint "1::nat" or
   132   even replaced by Suc 0; similar for old "2";
   133 
   134   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   135 
   136   - remove all special provisions on numerals in proofs;
   137 
   138 * HOL/record:
   139   - removed old "make" and "make_scheme" operations -- INCOMPATIBILITY;
   140   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   141   - provides cases/induct rules for use with corresponding Isar methods;
   142   - new derived operations "make" (for adding fields of current
   143     record), "extend" to promote fixed record to record scheme, and
   144     "truncate" for the reverse; cf. theorems "derived_defs", which are
   145     *not* declared as simp by default;
   146   - internal definitions directly based on a light-weight abstract
   147     theory of product types over typedef rather than datatype;
   148 
   149 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   150 
   151 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   152 (beware of argument permutation!);
   153 
   154 * HOL: linorder_less_split superseded by linorder_cases;
   155 
   156 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   157 to peripheral theory "Hilbert_Choice";
   158 
   159 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   160 in this (rare) case use:
   161 
   162   delSWrapper "split_all_tac"
   163   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   164 
   165 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   166 MAY FAIL;
   167 
   168 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   169 Isabelle's type classes, ^ on functions and relations has too general
   170 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   171 necessary to attach explicit type constraints;
   172 
   173 * HOL: syntax translations now work properly with numerals and records
   174 expressions;
   175 
   176 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   177 Florian Kammüller;
   178 
   179 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   180 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   181 renamed "Product_Type.unit";
   182 
   183 
   184 *** HOLCF ***
   185 
   186 * proper rep_datatype lift (see theory Lift); use plain induct_tac
   187 instead of former lift.induct_tac; always use UU instead of Undef;
   188 
   189 * 'domain' package adapted to new-style theories, e.g. see
   190 HOLCF/ex/Dnat.thy;
   191 
   192 
   193 *** ZF ***
   194 
   195 * ZF: the integer library now covers quotients and remainders, with
   196 many laws relating division to addition, multiplication, etc.;
   197 
   198 
   199 *** General ***
   200 
   201 * kernel: meta-level proof terms (by Stefan Berghofer), see also ref
   202 manual;
   203 
   204 * Pure/axclass: removed obsolete ML interface goal_subclass/goal_arity;
   205 
   206 * classical: renamed addaltern to addafter, addSaltern to addSafter;
   207 
   208 * clasimp: ``iff'' declarations now handle conditional rules as well;
   209 
   210 * syntax: new token syntax "num" for plain numerals (without "#" of
   211 "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now separate
   212 tokens, so expressions involving minus need to be spaced properly;
   213 
   214 * syntax: support non-oriented infixes;
   215 
   216 * syntax: print modes "type_brackets" and "no_type_brackets" control
   217 output of nested => (types); the default behavior is "type_brackets";
   218 
   219 * syntax: builtin parse translation for "_constify" turns valued
   220 tokens into AST constants;
   221 
   222 * system: refrain from any attempt at filtering input streams; no
   223 longer support ``8bit'' encoding of old isabelle font, instead proper
   224 iso-latin characters may now be used;
   225 
   226 * system: support Poly/ML 4.1.1 (now able to manage large heaps);
   227 
   228 * system: Proof General keywords specification is now part of the
   229 Isabelle distribution (see etc/isar-keywords.el);
   230 
   231 * system: smart selection of Isabelle process versus Isabelle
   232 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   233 run both "isabelle" and "Isabelle" even if file names are badly
   234 damaged (executable inspects the case of the first letter of its own
   235 name); added separate "isabelle-process" and "isabelle-interface";
   236 
   237 
   238 
   239 New in Isabelle99-2 (February 2001)
   240 -----------------------------------
   241 
   242 *** Overview of INCOMPATIBILITIES ***
   243 
   244 * HOL: please note that theories in the Library and elsewhere often use the
   245 new-style (Isar) format; to refer to their theorems in an ML script you must
   246 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   247 
   248 * HOL: inductive package no longer splits induction rule aggressively,
   249 but only as far as specified by the introductions given; the old
   250 format may be recovered via ML function complete_split_rule or attribute
   251 'split_rule (complete)';
   252 
   253 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   254 gfp_Tarski to gfp_unfold;
   255 
   256 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   257 
   258 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   259 relation); infix "^^" has been renamed "``"; infix "``" has been
   260 renamed "`"; "univalent" has been renamed "single_valued";
   261 
   262 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   263 operation;
   264 
   265 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   266 
   267 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   268 
   269 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   270 consequence, it is no longer monotonic wrt. the local goal context
   271 (which is now passed through the inductive cases);
   272 
   273 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   274 \<gg> to \<ggreater>;
   275 
   276 
   277 *** Document preparation ***
   278 
   279 * \isabellestyle{NAME} selects version of Isabelle output (currently
   280 available: are "it" for near math-mode best-style output, "sl" for
   281 slanted text style, and "tt" for plain type-writer; if no
   282 \isabellestyle command is given, output is according to slanted
   283 type-writer);
   284 
   285 * support sub/super scripts (for single symbols only), input syntax is
   286 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   287 
   288 * some more standard symbols; see Appendix A of the system manual for
   289 the complete list of symbols defined in isabellesym.sty;
   290 
   291 * improved isabelle style files; more abstract symbol implementation
   292 (should now use \isamath{...} and \isatext{...} in custom symbol
   293 definitions);
   294 
   295 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   296 state; Note that presentation of goal states does not conform to
   297 actual human-readable proof documents.  Please do not include goal
   298 states into document output unless you really know what you are doing!
   299 
   300 * proper indentation of antiquoted output with proportional LaTeX
   301 fonts;
   302 
   303 * no_document ML operator temporarily disables LaTeX document
   304 generation;
   305 
   306 * isatool unsymbolize tunes sources for plain ASCII communication;
   307 
   308 
   309 *** Isar ***
   310 
   311 * Pure: Isar now suffers initial goal statements to contain unbound
   312 schematic variables (this does not conform to actual readable proof
   313 documents, due to unpredictable outcome and non-compositional proof
   314 checking); users who know what they are doing may use schematic goals
   315 for Prolog-style synthesis of proven results;
   316 
   317 * Pure: assumption method (an implicit finishing) now handles actual
   318 rules as well;
   319 
   320 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   321 initial goal, declare "that" only as Pure intro (only for single
   322 steps); the "that" rule assumption may now be involved in implicit
   323 finishing, thus ".." becomes a feasible for trivial obtains;
   324 
   325 * Pure: default proof step now includes 'intro_classes'; thus trivial
   326 instance proofs may be performed by "..";
   327 
   328 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   329 statements as well;
   330 
   331 * Pure: more robust selection of calculational rules;
   332 
   333 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   334 rule (as well as the assumption rule);
   335 
   336 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   337 lemmas, using the graph browser tool;
   338 
   339 * Pure: predict failure of "show" in interactive mode;
   340 
   341 * Pure: 'thms_containing' now takes actual terms as arguments;
   342 
   343 * HOL: improved method 'induct' --- now handles non-atomic goals
   344 (potential INCOMPATIBILITY); tuned error handling;
   345 
   346 * HOL: cases and induct rules now provide explicit hints about the
   347 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   348 any remaining facts are inserted into the goal verbatim;
   349 
   350 * HOL: local contexts (aka cases) may now contain term bindings as
   351 well; the 'cases' and 'induct' methods new provide a ?case binding for
   352 the result to be shown in each case;
   353 
   354 * HOL: added 'recdef_tc' command;
   355 
   356 * isatool convert assists in eliminating legacy ML scripts;
   357 
   358 
   359 *** HOL ***
   360 
   361 * HOL/Library: a collection of generic theories to be used together
   362 with main HOL; the theory loader path already includes this directory
   363 by default; the following existing theories have been moved here:
   364 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   365 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   366 
   367 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   368 modelling and verification task performed in Isabelle/HOL +
   369 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   370 
   371 * HOL/Algebra: special summation operator SUM no longer exists, it has
   372 been replaced by setsum; infix 'assoc' now has priority 50 (like
   373 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   374 'domain', this makes the theory consistent with mathematical
   375 literature;
   376 
   377 * HOL basics: added overloaded operations "inverse" and "divide"
   378 (infix "/"), syntax for generic "abs" operation, generic summation
   379 operator \<Sum>;
   380 
   381 * HOL/typedef: simplified package, provide more useful rules (see also
   382 HOL/subset.thy);
   383 
   384 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   385 now expressed as a proper nested rule (old-style tactic scripts may
   386 require atomize_strip_tac to cope with non-atomic premises);
   387 
   388 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   389 to "split_conv" (old name still available for compatibility);
   390 
   391 * HOL: improved concrete syntax for strings (e.g. allows translation
   392 rules with string literals);
   393 
   394 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   395 and Fleuriot's mechanization of analysis;
   396 
   397 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   398 
   399 
   400 *** CTT ***
   401 
   402 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   403 "lam" is displayed as TWO lambda-symbols
   404 
   405 * CTT: theory Main now available, containing everything (that is, Bool
   406 and Arith);
   407 
   408 
   409 *** General ***
   410 
   411 * Pure: the Simplifier has been implemented properly as a derived rule
   412 outside of the actual kernel (at last!); the overall performance
   413 penalty in practical applications is about 50%, while reliability of
   414 the Isabelle inference kernel has been greatly improved;
   415 
   416 * print modes "brackets" and "no_brackets" control output of nested =>
   417 (types) and ==> (props); the default behaviour is "brackets";
   418 
   419 * Provers: fast_tac (and friends) now handle actual object-logic rules
   420 as assumptions as well;
   421 
   422 * system: support Poly/ML 4.0;
   423 
   424 * system: isatool install handles KDE version 1 or 2;
   425 
   426 
   427 
   428 New in Isabelle99-1 (October 2000)
   429 ----------------------------------
   430 
   431 *** Overview of INCOMPATIBILITIES ***
   432 
   433 * HOL: simplification of natural numbers is much changed; to partly
   434 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   435 issue the following ML commands:
   436 
   437   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   438   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   439 
   440 * HOL: simplification no longer dives into case-expressions; this is
   441 controlled by "t.weak_case_cong" for each datatype t;
   442 
   443 * HOL: nat_less_induct renamed to less_induct;
   444 
   445 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   446 fixsome to patch .thy and .ML sources automatically;
   447 
   448   select_equality  -> some_equality
   449   select_eq_Ex     -> some_eq_ex
   450   selectI2EX       -> someI2_ex
   451   selectI2         -> someI2
   452   selectI          -> someI
   453   select1_equality -> some1_equality
   454   Eps_sym_eq       -> some_sym_eq_trivial
   455   Eps_eq           -> some_eq_trivial
   456 
   457 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   458 
   459 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   460 instead);
   461 
   462 * HOL: the recursion equations generated by 'recdef' are now called
   463 f.simps instead of f.rules;
   464 
   465 * HOL: qed_spec_mp now also handles bounded ALL as well;
   466 
   467 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   468 sometimes be needed;
   469 
   470 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   471 
   472 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   473 
   474 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   475 product is now "<*>" instead of "Times"; the lexicographic product is
   476 now "<*lex*>" instead of "**";
   477 
   478 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   479 of main HOL, but was unused); better use HOL's datatype package;
   480 
   481 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   482 the old syntax may be recovered as follows:
   483 
   484   syntax (symbols)
   485     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   486       (infixl "\\<oplus>" 100)
   487 
   488 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   489 
   490 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   491 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   492 internally;
   493 
   494 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   495 changed from A/r to A//r;
   496 
   497 * ZF: new treatment of arithmetic (nat & int) may break some old
   498 proofs;
   499 
   500 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   501 rulify -> rule_format, elimify -> elim_format, ...);
   502 
   503 * Isar/Provers: intro/elim/dest attributes changed; renamed
   504 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   505 should have to change intro!! to intro? only); replaced "delrule" by
   506 "rule del";
   507 
   508 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   509 
   510 * Provers: strengthened force_tac by using new first_best_tac;
   511 
   512 * LaTeX document preparation: several changes of isabelle.sty (see
   513 lib/texinputs);
   514 
   515 
   516 *** Document preparation ***
   517 
   518 * formal comments (text blocks etc.) in new-style theories may now
   519 contain antiquotations of thm/prop/term/typ/text to be presented
   520 according to latex print mode; concrete syntax is like this:
   521 @{term[show_types] "f(x) = a + x"};
   522 
   523 * isatool mkdir provides easy setup of Isabelle session directories,
   524 including proper document sources;
   525 
   526 * generated LaTeX sources are now deleted after successful run
   527 (isatool document -c); may retain a copy somewhere else via -D option
   528 of isatool usedir;
   529 
   530 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   531 style files, achieving self-contained LaTeX sources and simplifying
   532 LaTeX debugging;
   533 
   534 * old-style theories now produce (crude) LaTeX output as well;
   535 
   536 * browser info session directories are now self-contained (may be put
   537 on WWW server seperately); improved graphs of nested sessions; removed
   538 graph for 'all sessions';
   539 
   540 * several improvements in isabelle style files; \isabellestyle{it}
   541 produces fake math mode output; \isamarkupheader is now \section by
   542 default; see lib/texinputs/isabelle.sty etc.;
   543 
   544 
   545 *** Isar ***
   546 
   547 * Isar/Pure: local results and corresponding term bindings are now
   548 subject to Hindley-Milner polymorphism (similar to ML); this
   549 accommodates incremental type-inference very nicely;
   550 
   551 * Isar/Pure: new derived language element 'obtain' supports
   552 generalized existence reasoning;
   553 
   554 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   555 support accumulation of results, without applying any rules yet;
   556 useful to collect intermediate results without explicit name
   557 references, and for use with transitivity rules with more than 2
   558 premises;
   559 
   560 * Isar/Pure: scalable support for case-analysis type proofs: new
   561 'case' language element refers to local contexts symbolically, as
   562 produced by certain proof methods; internally, case names are attached
   563 to theorems as "tags";
   564 
   565 * Isar/Pure: theory command 'hide' removes declarations from
   566 class/type/const name spaces;
   567 
   568 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   569 indicate potential overloading;
   570 
   571 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   572 
   573 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   574 "{a,b,c}" instead of {a,b,c};
   575 
   576 * Isar/Pure now provides its own version of intro/elim/dest
   577 attributes; useful for building new logics, but beware of confusion
   578 with the version in Provers/classical;
   579 
   580 * Isar/Pure: the local context of (non-atomic) goals is provided via
   581 case name 'antecedent';
   582 
   583 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   584 to the current context is now done automatically);
   585 
   586 * Isar/Pure: theory command 'method_setup' provides a simple interface
   587 for definining proof methods in ML;
   588 
   589 * Isar/Provers: intro/elim/dest attributes changed; renamed
   590 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   591 most cases, one should have to change intro!! to intro? only);
   592 replaced "delrule" by "rule del";
   593 
   594 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   595 'symmetric' attribute (the latter supercedes [RS sym]);
   596 
   597 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   598 method modifier); 'simp' method: 'only:' modifier removes loopers as
   599 well (including splits);
   600 
   601 * Isar/Provers: Simplifier and Classical methods now support all kind
   602 of modifiers used in the past, including 'cong', 'iff', etc.
   603 
   604 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   605 of Simplifier and Classical reasoner);
   606 
   607 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   608 now support named cases; major packages (inductive, datatype, primrec,
   609 recdef) support case names and properly name parameters;
   610 
   611 * Isar/HOL: new transitivity rules for substitution in inequalities --
   612 monotonicity conditions are extracted to be proven at end of
   613 calculations;
   614 
   615 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   616 method anyway;
   617 
   618 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   619 split_if split_if_asm; datatype package provides theorems foo.splits =
   620 foo.split foo.split_asm for each datatype;
   621 
   622 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   623 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   624 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   625 use "(cases (simplified))" method in proper proof texts);
   626 
   627 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   628 
   629 * Isar: names of theorems etc. may be natural numbers as well;
   630 
   631 * Isar: 'pr' command: optional arguments for goals_limit and
   632 ProofContext.prems_limit; no longer prints theory contexts, but only
   633 proof states;
   634 
   635 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   636 additional print modes to be specified; e.g. "pr(latex)" will print
   637 proof state according to the Isabelle LaTeX style;
   638 
   639 * Isar: improved support for emulating tactic scripts, including proof
   640 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   641 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   642 (for HOL datatypes);
   643 
   644 * Isar: simplified (more robust) goal selection of proof methods: 1st
   645 goal, all goals, or explicit goal specifier (tactic emulation); thus
   646 'proof method scripts' have to be in depth-first order;
   647 
   648 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   649 
   650 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   651 should instead use individual commands for printing items
   652 (print_commands, print_methods etc.);
   653 
   654 * Isar: added 'nothing' --- the empty list of theorems;
   655 
   656 
   657 *** HOL ***
   658 
   659 * HOL/MicroJava: formalization of a fragment of Java, together with a
   660 corresponding virtual machine and a specification of its bytecode
   661 verifier and a lightweight bytecode verifier, including proofs of
   662 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   663 Cornelia Pusch (see also the homepage of project Bali at
   664 http://isabelle.in.tum.de/Bali/);
   665 
   666 * HOL/Algebra: new theory of rings and univariate polynomials, by
   667 Clemens Ballarin;
   668 
   669 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   670 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   671 Rasmussen;
   672 
   673 * HOL/Lattice: fundamental concepts of lattice theory and order
   674 structures, including duals, properties of bounds versus algebraic
   675 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   676 Theorem for complete lattices etc.; may also serve as a demonstration
   677 for abstract algebraic reasoning using axiomatic type classes, and
   678 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   679 
   680 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   681 von Oheimb;
   682 
   683 * HOL/IMPP: extension of IMP with local variables and mutually
   684 recursive procedures, by David von Oheimb;
   685 
   686 * HOL/Lambda: converted into new-style theory and document;
   687 
   688 * HOL/ex/Multiquote: example of multiple nested quotations and
   689 anti-quotations -- basically a generalized version of de-Bruijn
   690 representation; very useful in avoiding lifting of operations;
   691 
   692 * HOL/record: added general record equality rule to simpset; fixed
   693 select-update simplification procedure to handle extended records as
   694 well; admit "r" as field name;
   695 
   696 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   697 other numeric types and also as the identity of groups, rings, etc.;
   698 
   699 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   700 Types nat and int belong to this axclass;
   701 
   702 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   703    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   704    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   705   two terms #m*u and #n*u are replaced by #(m+n)*u
   706     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   707   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   708     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   709 
   710 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   711 powerful prover for predicate logic but knows nothing of clasets; see
   712 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   713 
   714 * HOL: new version of "case_tac" subsumes both boolean case split and
   715 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   716 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   717 
   718 * HOL: simplification no longer dives into case-expressions: only the
   719 selector expression is simplified, but not the remaining arms; to
   720 enable full simplification of case-expressions for datatype t, you may
   721 remove t.weak_case_cong from the simpset, either globally (Delcongs
   722 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   723 
   724 * HOL/recdef: the recursion equations generated by 'recdef' for
   725 function 'f' are now called f.simps instead of f.rules; if all
   726 termination conditions are proved automatically, these simplification
   727 rules are added to the simpset, as in primrec; rules may be named
   728 individually as well, resulting in a separate list of theorems for
   729 each equation;
   730 
   731 * HOL/While is a new theory that provides a while-combinator. It
   732 permits the definition of tail-recursive functions without the
   733 provision of a termination measure. The latter is necessary once the
   734 invariant proof rule for while is applied.
   735 
   736 * HOL: new (overloaded) notation for the set of elements below/above
   737 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   738 
   739 * HOL: theorems impI, allI, ballI bound as "strip";
   740 
   741 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   742 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   743 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   744 
   745 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   746 
   747 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   748 main HOL, but was unused);
   749 
   750 * HOL: fewer consts declared as global (e.g. have to refer to
   751 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   752 
   753 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   754 in case of overlap with user translations (e.g. judgements over
   755 tuples); (note that the underlying logical represenation is still
   756 bogus);
   757 
   758 
   759 *** ZF ***
   760 
   761 * ZF: simplification automatically cancels common terms in arithmetic
   762 expressions over nat and int;
   763 
   764 * ZF: new treatment of nat to minimize type-checking: all operators
   765 coerce their operands to a natural number using the function natify,
   766 making the algebraic laws unconditional;
   767 
   768 * ZF: as above, for int: operators coerce their operands to an integer
   769 using the function intify;
   770 
   771 * ZF: the integer library now contains many of the usual laws for the
   772 orderings, including $<=, and monotonicity laws for $+ and $*;
   773 
   774 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   775 simplification;
   776 
   777 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   778 to the simplifier and classical reasoner simultaneously;
   779 
   780 
   781 *** General ***
   782 
   783 * Provers: blast_tac now handles actual object-logic rules as
   784 assumptions; note that auto_tac uses blast_tac internally as well;
   785 
   786 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   787 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   788 
   789 * Provers: delrules now handles destruct rules as well (no longer need
   790 explicit make_elim);
   791 
   792 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   793   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   794 use instead the strong form,
   795   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   796 in HOL, FOL and ZF the function cla_make_elim will create such rules
   797 from destruct-rules;
   798 
   799 * Provers: Simplifier.easy_setup provides a fast path to basic
   800 Simplifier setup for new object-logics;
   801 
   802 * Pure: AST translation rules no longer require constant head on LHS;
   803 
   804 * Pure: improved name spaces: ambiguous output is qualified; support
   805 for hiding of names;
   806 
   807 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   808 XSYMBOL_HOME; no longer need to do manual configuration in most
   809 situations;
   810 
   811 * system: compression of ML heaps images may now be controlled via -c
   812 option of isabelle and isatool usedir (currently only observed by
   813 Poly/ML);
   814 
   815 * system: isatool installfonts may handle X-Symbol fonts as well (very
   816 useful for remote X11);
   817 
   818 * system: provide TAGS file for Isabelle sources;
   819 
   820 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   821 order;
   822 
   823 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   824 timing flag supersedes proof_timing and Toplevel.trace;
   825 
   826 * ML: new combinators |>> and |>>> for incremental transformations
   827 with secondary results (e.g. certain theory extensions):
   828 
   829 * ML: PureThy.add_defs gets additional argument to indicate potential
   830 overloading (usually false);
   831 
   832 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   833 results;
   834 
   835 
   836 
   837 New in Isabelle99 (October 1999)
   838 --------------------------------
   839 
   840 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   841 
   842 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   843 are no longer simplified.  (This allows the simplifier to unfold recursive
   844 functional programs.)  To restore the old behaviour, declare
   845 
   846     Delcongs [if_weak_cong];
   847 
   848 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   849 complement;
   850 
   851 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   852 
   853 * HOL/datatype: mutual_induct_tac no longer exists --
   854   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   855 
   856 * HOL/typedef: fixed type inference for representing set; type
   857 arguments now have to occur explicitly on the rhs as type constraints;
   858 
   859 * ZF: The con_defs part of an inductive definition may no longer refer
   860 to constants declared in the same theory;
   861 
   862 * HOL, ZF: the function mk_cases, generated by the inductive
   863 definition package, has lost an argument.  To simplify its result, it
   864 uses the default simpset instead of a supplied list of theorems.
   865 
   866 * HOL/List: the constructors of type list are now Nil and Cons;
   867 
   868 * Simplifier: the type of the infix ML functions
   869         setSSolver addSSolver setSolver addSolver
   870 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   871 for packaging solvers. A solver is created via
   872         mk_solver: string -> (thm list -> int -> tactic) -> solver
   873 where the string argument is only a comment.
   874 
   875 
   876 *** Proof tools ***
   877 
   878 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   879 decision procedure for linear arithmetic. Currently it is used for
   880 types `nat', `int', and `real' in HOL (see below); it can, should and
   881 will be instantiated for other types and logics as well.
   882 
   883 * The simplifier now accepts rewrite rules with flexible heads, eg
   884      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   885   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   886   matching.
   887 
   888 
   889 *** General ***
   890 
   891 * New Isabelle/Isar subsystem provides an alternative to traditional
   892 tactical theorem proving; together with the ProofGeneral/isar user
   893 interface it offers an interactive environment for developing human
   894 readable proof documents (Isar == Intelligible semi-automated
   895 reasoning); for further information see isatool doc isar-ref,
   896 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   897 
   898 * improved and simplified presentation of theories: better HTML markup
   899 (including colors), graph views in several sizes; isatool usedir now
   900 provides a proper interface for user theories (via -P option); actual
   901 document preparation based on (PDF)LaTeX is available as well (for
   902 new-style theories only); see isatool doc system for more information;
   903 
   904 * native support for Proof General, both for classic Isabelle and
   905 Isabelle/Isar;
   906 
   907 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   908 using the graph browser tool;
   909 
   910 * Isabelle manuals now also available as PDF;
   911 
   912 * theory loader rewritten from scratch (may not be fully
   913 bug-compatible); old loadpath variable has been replaced by show_path,
   914 add_path, del_path, reset_path functions; new operations such as
   915 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   916 isatool doc ref);
   917 
   918 * improved isatool install: option -k creates KDE application icon,
   919 option -p DIR installs standalone binaries;
   920 
   921 * added ML_PLATFORM setting (useful for cross-platform installations);
   922 more robust handling of platform specific ML images for SML/NJ;
   923 
   924 * the settings environment is now statically scoped, i.e. it is never
   925 created again in sub-processes invoked from isabelle, isatool, or
   926 Isabelle;
   927 
   928 * path element specification '~~' refers to '$ISABELLE_HOME';
   929 
   930 * in locales, the "assumes" and "defines" parts may be omitted if
   931 empty;
   932 
   933 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   934 long arrows);
   935 
   936 * new print_mode "HTML";
   937 
   938 * new flag show_tags controls display of tags of theorems (which are
   939 basically just comments that may be attached by some tools);
   940 
   941 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   942 mode and goal output format:
   943 
   944 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   945 244c244
   946 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   947 ---
   948 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   949 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   950 181c181
   951 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   952 ---
   953 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   954 
   955 * function bind_thms stores lists of theorems (cf. bind_thm);
   956 
   957 * new shorthand tactics ftac, eatac, datac, fatac;
   958 
   959 * qed (and friends) now accept "" as result name; in that case the
   960 theorem is not stored, but proper checks and presentation of the
   961 result still apply;
   962 
   963 * theorem database now also indexes constants "Trueprop", "all",
   964 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   965 
   966 
   967 *** HOL ***
   968 
   969 ** HOL arithmetic **
   970 
   971 * There are now decision procedures for linear arithmetic over nat and
   972 int:
   973 
   974 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   975 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   976 are treated as atomic; subformulae not involving type `nat' or `int'
   977 are ignored; quantified subformulae are ignored unless they are
   978 positive universal or negative existential. The tactic has to be
   979 invoked by hand and can be a little bit slow. In particular, the
   980 running time is exponential in the number of occurrences of `min' and
   981 `max', and `-' on `nat'.
   982 
   983 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   984 (negated) (in)equalities among the premises and the conclusion into
   985 account (i.e. no compound formulae) and does not know about `min' and
   986 `max', and `-' on `nat'. It is fast and is used automatically by the
   987 simplifier.
   988 
   989 NB: At the moment, these decision procedures do not cope with mixed
   990 nat/int formulae where the two parts interact, such as `m < n ==>
   991 int(m) < int(n)'.
   992 
   993 * HOL/Numeral provides a generic theory of numerals (encoded
   994 efficiently as bit strings); setup for types nat/int/real is in place;
   995 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   996 int, existing theories and proof scripts may require a few additional
   997 type constraints;
   998 
   999 * integer division and remainder can now be performed on constant
  1000 arguments;
  1001 
  1002 * many properties of integer multiplication, division and remainder
  1003 are now available;
  1004 
  1005 * An interface to the Stanford Validity Checker (SVC) is available through the
  1006 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1007 are proved automatically.  SVC must be installed separately, and its results
  1008 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1009 invocation of the underlying oracle).  For SVC see
  1010   http://verify.stanford.edu/SVC
  1011 
  1012 * IsaMakefile: the HOL-Real target now builds an actual image;
  1013 
  1014 
  1015 ** HOL misc **
  1016 
  1017 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1018 (in Isabelle/Isar) -- by Gertrud Bauer;
  1019 
  1020 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1021 analysis for assembly languages with subtypes;
  1022 
  1023 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1024 -- avoids syntactic ambiguities and treats state, transition, and
  1025 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1026 changed syntax and (many) tactics;
  1027 
  1028 * HOL/inductive: Now also handles more general introduction rules such
  1029   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1030   theorems are now maintained within the theory (maintained via the
  1031   "mono" attribute);
  1032 
  1033 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1034   (using function types) such as
  1035 
  1036   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1037 
  1038 * HOL/record: record_simproc (part of the default simpset) takes care
  1039 of selectors applied to updated records; record_split_tac is no longer
  1040 part of the default claset; update_defs may now be removed from the
  1041 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1042 
  1043   claset_ref () := claset() addSWrapper record_split_wrapper;
  1044   Delsimprocs [record_simproc]
  1045 
  1046 * HOL/typedef: fixed type inference for representing set; type
  1047 arguments now have to occur explicitly on the rhs as type constraints;
  1048 
  1049 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1050 names rather than an ML expression;
  1051 
  1052 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1053 supplied later.  Program schemes can be defined, such as
  1054     "While B C s = (if B s then While B C (C s) else s)"
  1055 where the well-founded relation can be chosen after B and C have been given.
  1056 
  1057 * HOL/List: the constructors of type list are now Nil and Cons;
  1058 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1059 course, ML tools referring to List.list.op # etc. have to be adapted;
  1060 
  1061 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1062 disabled by default; run isabelle with option -m HOL to get back to
  1063 the original Gordon/HOL-style output;
  1064 
  1065 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1066 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1067 
  1068 * HOL basic syntax simplified (more orthogonal): all variants of
  1069 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1070 Eps operator is provided as well: "SOME x. P[x]";
  1071 
  1072 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1073 
  1074 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1075 thus available for user theories;
  1076 
  1077 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1078 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1079 time;
  1080 
  1081 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1082 several times and then mp;
  1083 
  1084 
  1085 *** LK ***
  1086 
  1087 * the notation <<...>> is now available as a notation for sequences of
  1088 formulas;
  1089 
  1090 * the simplifier is now installed
  1091 
  1092 * the axiom system has been generalized (thanks to Soren Heilmann)
  1093 
  1094 * the classical reasoner now has a default rule database
  1095 
  1096 
  1097 *** ZF ***
  1098 
  1099 * new primrec section allows primitive recursive functions to be given
  1100 directly (as in HOL) over datatypes and the natural numbers;
  1101 
  1102 * new tactics induct_tac and exhaust_tac for induction (or case
  1103 analysis) over datatypes and the natural numbers;
  1104 
  1105 * the datatype declaration of type T now defines the recursor T_rec;
  1106 
  1107 * simplification automatically does freeness reasoning for datatype
  1108 constructors;
  1109 
  1110 * automatic type-inference, with AddTCs command to insert new
  1111 type-checking rules;
  1112 
  1113 * datatype introduction rules are now added as Safe Introduction rules
  1114 to the claset;
  1115 
  1116 * the syntax "if P then x else y" is now available in addition to
  1117 if(P,x,y);
  1118 
  1119 
  1120 *** Internal programming interfaces ***
  1121 
  1122 * tuned simplifier trace output; new flag debug_simp;
  1123 
  1124 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1125 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1126 
  1127 * AxClass.axclass_tac lost the theory argument;
  1128 
  1129 * tuned current_goals_markers semantics: begin / end goal avoids
  1130 printing empty lines;
  1131 
  1132 * removed prs and prs_fn hook, which was broken because it did not
  1133 include \n in its semantics, forcing writeln to add one
  1134 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1135 string -> unit if you really want to output text without newline;
  1136 
  1137 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1138 plain output, interface builders may have to enable 'isabelle_font'
  1139 mode to get Isabelle font glyphs as before;
  1140 
  1141 * refined token_translation interface; INCOMPATIBILITY: output length
  1142 now of type real instead of int;
  1143 
  1144 * theory loader actions may be traced via new ThyInfo.add_hook
  1145 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1146 your own database of information attached to *whole* theories -- as
  1147 opposed to intra-theory data slots offered via TheoryDataFun;
  1148 
  1149 * proper handling of dangling sort hypotheses (at last!);
  1150 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1151 extra sort hypotheses that can be witnessed from the type signature;
  1152 the force_strip_shyps flag is gone, any remaining shyps are simply
  1153 left in the theorem (with a warning issued by strip_shyps_warning);
  1154 
  1155 
  1156 
  1157 New in Isabelle98-1 (October 1998)
  1158 ----------------------------------
  1159 
  1160 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1161 
  1162 * several changes of automated proof tools;
  1163 
  1164 * HOL: major changes to the inductive and datatype packages, including
  1165 some minor incompatibilities of theory syntax;
  1166 
  1167 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1168 called `inj_on';
  1169 
  1170 * HOL: removed duplicate thms in Arith:
  1171   less_imp_add_less  should be replaced by  trans_less_add1
  1172   le_imp_add_le      should be replaced by  trans_le_add1
  1173 
  1174 * HOL: unary minus is now overloaded (new type constraints may be
  1175 required);
  1176 
  1177 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1178 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1179 now taken as an integer constant.
  1180 
  1181 * Pure: ML function 'theory_of' renamed to 'theory';
  1182 
  1183 
  1184 *** Proof tools ***
  1185 
  1186 * Simplifier:
  1187   1. Asm_full_simp_tac is now more aggressive.
  1188      1. It will sometimes reorient premises if that increases their power to
  1189         simplify.
  1190      2. It does no longer proceed strictly from left to right but may also
  1191         rotate premises to achieve further simplification.
  1192      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1193      old Asm_full_simp_tac in that it does not rotate premises.
  1194   2. The simplifier now knows a little bit about nat-arithmetic.
  1195 
  1196 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1197 allows for selected deletion of wrappers, by introduction of names for
  1198 wrapper functionals.  This implies that addbefore, addSbefore,
  1199 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1200 and that adding two tactics with the same name overwrites the first
  1201 one (emitting a warning).
  1202   type wrapper = (int -> tactic) -> (int -> tactic)
  1203   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1204   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1205   delWrapper, delSWrapper: claset *  string            -> claset
  1206   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1207 
  1208 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1209 semantics; addbefore now affects only the unsafe part of step_tac
  1210 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1211 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1212 by Force_tac;
  1213 
  1214 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1215 compWrapper; added safe wrapper (and access functions for it);
  1216 
  1217 * HOL/split_all_tac is now much faster and fails if there is nothing
  1218 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1219 and the names of the automatically generated variables have changed.
  1220 split_all_tac has moved within claset() from unsafe wrappers to safe
  1221 wrappers, which means that !!-bound variables are split much more
  1222 aggressively, and safe_tac and clarify_tac now split such variables.
  1223 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1224 Note: the same holds for record_split_tac, which does the job of
  1225 split_all_tac for record fields.
  1226 
  1227 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1228 permanently to the default simpset using Addsplits just like
  1229 Addsimps. They can be removed via Delsplits just like
  1230 Delsimps. Lower-case versions are also available.
  1231 
  1232 * HOL/Simplifier: The rule split_if is now part of the default
  1233 simpset. This means that the simplifier will eliminate all occurrences
  1234 of if-then-else in the conclusion of a goal. To prevent this, you can
  1235 either remove split_if completely from the default simpset by
  1236 `Delsplits [split_if]' or remove it in a specific call of the
  1237 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1238 other case splitting rules to/from the default simpset: every datatype
  1239 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1240 t is the name of the datatype).
  1241 
  1242 * Classical reasoner / Simplifier combination: new force_tac (and
  1243 derivatives Force_tac, force) combines rewriting and classical
  1244 reasoning (and whatever other tools) similarly to auto_tac, but is
  1245 aimed to solve the given subgoal completely.
  1246 
  1247 
  1248 *** General ***
  1249 
  1250 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1251 and `goalw': the theory is no longer needed as an explicit argument -
  1252 the current theory context is used; assumptions are no longer returned
  1253 at the ML-level unless one of them starts with ==> or !!; it is
  1254 recommended to convert to these new commands using isatool fixgoal
  1255 (backup your sources first!);
  1256 
  1257 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1258 the current theory context, and 'theory' to lookup stored theories;
  1259 
  1260 * new theory section 'locale' for declaring constants, assumptions and
  1261 definitions that have local scope;
  1262 
  1263 * new theory section 'nonterminals' for purely syntactic types;
  1264 
  1265 * new theory section 'setup' for generic ML setup functions
  1266 (e.g. package initialization);
  1267 
  1268 * the distribution now includes Isabelle icons: see
  1269 lib/logo/isabelle-{small,tiny}.xpm;
  1270 
  1271 * isatool install - install binaries with absolute references to
  1272 ISABELLE_HOME/bin;
  1273 
  1274 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1275 
  1276 * print mode 'emacs' reserved for Isamode;
  1277 
  1278 * support multiple print (ast) translations per constant name;
  1279 
  1280 * theorems involving oracles are now printed with a suffixed [!];
  1281 
  1282 
  1283 *** HOL ***
  1284 
  1285 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1286 
  1287 * HOL/inductive package reorganized and improved: now supports mutual
  1288 definitions such as
  1289 
  1290   inductive EVEN ODD
  1291     intrs
  1292       null "0 : EVEN"
  1293       oddI "n : EVEN ==> Suc n : ODD"
  1294       evenI "n : ODD ==> Suc n : EVEN"
  1295 
  1296 new theorem list "elims" contains an elimination rule for each of the
  1297 recursive sets; inductive definitions now handle disjunctive premises
  1298 correctly (also ZF);
  1299 
  1300 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1301 "mutual_induct" no longer exists - the induction rule is always
  1302 contained in "induct";
  1303 
  1304 
  1305 * HOL/datatype package re-implemented and greatly improved: now
  1306 supports mutually recursive datatypes such as
  1307 
  1308   datatype
  1309     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1310             | SUM ('a aexp) ('a aexp)
  1311             | DIFF ('a aexp) ('a aexp)
  1312             | NUM 'a
  1313   and
  1314     'a bexp = LESS ('a aexp) ('a aexp)
  1315             | AND ('a bexp) ('a bexp)
  1316             | OR ('a bexp) ('a bexp)
  1317 
  1318 as well as indirectly recursive datatypes such as
  1319 
  1320   datatype
  1321     ('a, 'b) term = Var 'a
  1322                   | App 'b ((('a, 'b) term) list)
  1323 
  1324 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1325 induction on mutually / indirectly recursive datatypes.
  1326 
  1327 Primrec equations are now stored in theory and can be accessed via
  1328 <function_name>.simps.
  1329 
  1330 INCOMPATIBILITIES:
  1331 
  1332   - Theories using datatypes must now have theory Datatype as an
  1333     ancestor.
  1334   - The specific <typename>.induct_tac no longer exists - use the
  1335     generic induct_tac instead.
  1336   - natE has been renamed to nat.exhaust - use exhaust_tac
  1337     instead of res_inst_tac ... natE. Note that the variable
  1338     names in nat.exhaust differ from the names in natE, this
  1339     may cause some "fragile" proofs to fail.
  1340   - The theorems split_<typename>_case and split_<typename>_case_asm
  1341     have been renamed to <typename>.split and <typename>.split_asm.
  1342   - Since default sorts of type variables are now handled correctly,
  1343     some datatype definitions may have to be annotated with explicit
  1344     sort constraints.
  1345   - Primrec definitions no longer require function name and type
  1346     of recursive argument.
  1347 
  1348 Consider using isatool fixdatatype to adapt your theories and proof
  1349 scripts to the new package (backup your sources first!).
  1350 
  1351 
  1352 * HOL/record package: considerably improved implementation; now
  1353 includes concrete syntax for record types, terms, updates; theorems
  1354 for surjective pairing and splitting !!-bound record variables; proof
  1355 support is as follows:
  1356 
  1357   1) standard conversions (selectors or updates applied to record
  1358 constructor terms) are part of the standard simpset;
  1359 
  1360   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1361 made part of standard simpset and claset via addIffs;
  1362 
  1363   3) a tactic for record field splitting (record_split_tac) is part of
  1364 the standard claset (addSWrapper);
  1365 
  1366 To get a better idea about these rules you may retrieve them via
  1367 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1368 the name of your record type.
  1369 
  1370 The split tactic 3) conceptually simplifies by the following rule:
  1371 
  1372   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1373 
  1374 Thus any record variable that is bound by meta-all will automatically
  1375 blow up into some record constructor term, consequently the
  1376 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1377 solve record problems automatically.
  1378 
  1379 
  1380 * reorganized the main HOL image: HOL/Integ and String loaded by
  1381 default; theory Main includes everything;
  1382 
  1383 * automatic simplification of integer sums and comparisons, using cancellation;
  1384 
  1385 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1386 
  1387 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1388 
  1389 * many new identities for unions, intersections, set difference, etc.;
  1390 
  1391 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1392 called split_if, split_split, split_sum_case and split_nat_case (to go
  1393 with add/delsplits);
  1394 
  1395 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1396 (?x::unit) = (); this is made part of the default simpset, which COULD
  1397 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1398 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1399 unit_abs_eta_conv is added in order to counter the effect of
  1400 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1401 %u.f();
  1402 
  1403 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1404 makes more sense);
  1405 
  1406 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1407   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1408   disjointness reasoning but breaking a few old proofs.
  1409 
  1410 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1411 to 'converse' from 'inverse' (for compatibility with ZF and some
  1412 literature);
  1413 
  1414 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1415 the well-founded relation;
  1416 
  1417 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1418     Compl A.  The "Compl" syntax remains available as input syntax for this
  1419     release ONLY.
  1420 
  1421 * HOL/Update: new theory of function updates:
  1422     f(a:=b) == %x. if x=a then b else f x
  1423 may also be iterated as in f(a:=b,c:=d,...);
  1424 
  1425 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1426 
  1427 * HOL/List:
  1428   - new function list_update written xs[i:=v] that updates the i-th
  1429     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1430   - new function `upt' written [i..j(] which generates the list
  1431     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1432     bound write [i..j], which is a shorthand for [i..j+1(].
  1433   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1434 
  1435 * HOL/Arith:
  1436   - removed 'pred' (predecessor) function;
  1437   - generalized some theorems about n-1;
  1438   - many new laws about "div" and "mod";
  1439   - new laws about greatest common divisors (see theory ex/Primes);
  1440 
  1441 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1442 instead of "inverse";
  1443 
  1444 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1445   of the multiset ordering;
  1446 
  1447 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1448   (not included by default);
  1449 
  1450 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1451 
  1452 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1453   programs, i.e. different program variables may have different types.
  1454 
  1455 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1456   [previously, this check worked only if the rewrite rule was unconditional]
  1457   Now rew can involve either definitions or equalities (either == or =).
  1458 
  1459 
  1460 *** ZF ***
  1461 
  1462 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1463   only the theorems proved on ZF.ML;
  1464 
  1465 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1466   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1467   disjointness reasoning but breaking a few old proofs.
  1468 
  1469 * ZF/Update: new theory of function updates
  1470     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1471   may also be iterated as in f(a:=b,c:=d,...);
  1472 
  1473 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1474 
  1475 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1476   [previously, this check worked only if the rewrite rule was unconditional]
  1477   Now rew can involve either definitions or equalities (either == or =).
  1478 
  1479 * case_tac provided for compatibility with HOL
  1480     (like the old excluded_middle_tac, but with subgoals swapped)
  1481 
  1482 
  1483 *** Internal programming interfaces ***
  1484 
  1485 * Pure: several new basic modules made available for general use, see
  1486 also src/Pure/README;
  1487 
  1488 * improved the theory data mechanism to support encapsulation (data
  1489 kind name replaced by private Object.kind, acting as authorization
  1490 key); new type-safe user interface via functor TheoryDataFun; generic
  1491 print_data function becomes basically useless;
  1492 
  1493 * removed global_names compatibility flag -- all theory declarations
  1494 are qualified by default;
  1495 
  1496 * module Pure/Syntax now offers quote / antiquote translation
  1497 functions (useful for Hoare logic etc. with implicit dependencies);
  1498 see HOL/ex/Antiquote for an example use;
  1499 
  1500 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1501 cterm -> thm;
  1502 
  1503 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1504 subgoal;
  1505 
  1506 * Display.print_goals function moved to Locale.print_goals;
  1507 
  1508 * standard print function for goals supports current_goals_markers
  1509 variable for marking begin of proof, end of proof, start of goal; the
  1510 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1511 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1512 for example;
  1513 
  1514 
  1515 
  1516 New in Isabelle98 (January 1998)
  1517 --------------------------------
  1518 
  1519 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1520 
  1521 * changed lexical syntax of terms / types: dots made part of long
  1522 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1523 
  1524 * simpset (and claset) reference variable replaced by functions
  1525 simpset / simpset_ref;
  1526 
  1527 * no longer supports theory aliases (via merge) and non-trivial
  1528 implicit merge of thms' signatures;
  1529 
  1530 * most internal names of constants changed due to qualified names;
  1531 
  1532 * changed Pure/Sequence interface (see Pure/seq.ML);
  1533 
  1534 
  1535 *** General Changes ***
  1536 
  1537 * hierachically structured name spaces (for consts, types, axms, thms
  1538 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1539 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1540 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1541 long_names for fully qualified output names; NOTE: ML programs
  1542 (special tactics, packages etc.) referring to internal names may have
  1543 to be adapted to cope with fully qualified names; in case of severe
  1544 backward campatibility problems try setting 'global_names' at compile
  1545 time to have enrything declared within a flat name space; one may also
  1546 fine tune name declarations in theories via the 'global' and 'local'
  1547 section;
  1548 
  1549 * reimplemented the implicit simpset and claset using the new anytype
  1550 data filed in signatures; references simpset:simpset ref etc. are
  1551 replaced by functions simpset:unit->simpset and
  1552 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1553 to patch your ML files accordingly;
  1554 
  1555 * HTML output now includes theory graph data for display with Java
  1556 applet or isatool browser; data generated automatically via isatool
  1557 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1558 
  1559 * defs may now be conditional; improved rewrite_goals_tac to handle
  1560 conditional equations;
  1561 
  1562 * defs now admits additional type arguments, using TYPE('a) syntax;
  1563 
  1564 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1565 creates a new theory node; implicit merge of thms' signatures is
  1566 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1567 transfer:theory->thm->thm in (rare) cases;
  1568 
  1569 * improved handling of draft signatures / theories; draft thms (and
  1570 ctyps, cterms) are automatically promoted to real ones;
  1571 
  1572 * slightly changed interfaces for oracles: admit many per theory, named
  1573 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1574 
  1575 * print_goals: optional output of const types (set show_consts and
  1576 show_types);
  1577 
  1578 * improved output of warnings (###) and errors (***);
  1579 
  1580 * subgoal_tac displays a warning if the new subgoal has type variables;
  1581 
  1582 * removed old README and Makefiles;
  1583 
  1584 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1585 
  1586 * removed obsolete init_pps and init_database;
  1587 
  1588 * deleted the obsolete tactical STATE, which was declared by
  1589     fun STATE tacfun st = tacfun st st;
  1590 
  1591 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1592 (which abbreviates $HOME);
  1593 
  1594 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1595 use isatool fixseq to adapt your ML programs (this works for fully
  1596 qualified references to the Sequence structure only!);
  1597 
  1598 * use_thy no longer requires writable current directory; it always
  1599 reloads .ML *and* .thy file, if either one is out of date;
  1600 
  1601 
  1602 *** Classical Reasoner ***
  1603 
  1604 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1605 tactics that use classical reasoning to simplify a subgoal without
  1606 splitting it into several subgoals;
  1607 
  1608 * Safe_tac: like safe_tac but uses the default claset;
  1609 
  1610 
  1611 *** Simplifier ***
  1612 
  1613 * added simplification meta rules:
  1614     (asm_)(full_)simplify: simpset -> thm -> thm;
  1615 
  1616 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1617 logics (again);
  1618 
  1619 * added prems argument to simplification procedures;
  1620 
  1621 * HOL, FOL, ZF: added infix function `addsplits':
  1622   instead of `<simpset> setloop (split_tac <thms>)'
  1623   you can simply write `<simpset> addsplits <thms>'
  1624 
  1625 
  1626 *** Syntax ***
  1627 
  1628 * TYPE('a) syntax for type reflection terms;
  1629 
  1630 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1631 
  1632 * pretty printer: changed order of mixfix annotation preference (again!);
  1633 
  1634 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1635 
  1636 
  1637 *** HOL ***
  1638 
  1639 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1640   with `addloop' of the simplifier to faciliate case splitting in premises.
  1641 
  1642 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1643 
  1644 * HOL/Auth: new protocol proofs including some for the Internet
  1645   protocol TLS;
  1646 
  1647 * HOL/Map: new theory of `maps' a la VDM;
  1648 
  1649 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1650 cancelling out common nat summands from =, <, <= (in)equalities, or
  1651 differences; simplification procedures nat_cancel_factor for
  1652 cancelling common factor from =, <, <= (in)equalities over natural
  1653 sums; nat_cancel contains both kinds of procedures, it is installed by
  1654 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1655 
  1656 * HOL/simplifier: terms of the form
  1657   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1658   are rewritten to
  1659   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1660   and those of the form
  1661   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1662   are rewritten to
  1663   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1664 
  1665 * HOL/datatype
  1666   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1667 
  1668   P(t_case f1 ... fn x) =
  1669      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1670         ...
  1671        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1672      )
  1673 
  1674   and a theorem `split_t_case_asm' of the form
  1675 
  1676   P(t_case f1 ... fn x) =
  1677     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1678         ...
  1679        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1680      )
  1681   which can be added to a simpset via `addsplits'. The existing theorems
  1682   expand_list_case and expand_option_case have been renamed to
  1683   split_list_case and split_option_case.
  1684 
  1685 * HOL/Arithmetic:
  1686   - `pred n' is automatically converted to `n-1'.
  1687     Users are strongly encouraged not to use `pred' any longer,
  1688     because it will disappear altogether at some point.
  1689   - Users are strongly encouraged to write "0 < n" rather than
  1690     "n ~= 0". Theorems and proof tools have been modified towards this
  1691     `standard'.
  1692 
  1693 * HOL/Lists:
  1694   the function "set_of_list" has been renamed "set" (and its theorems too);
  1695   the function "nth" now takes its arguments in the reverse order and
  1696   has acquired the infix notation "!" as in "xs!n".
  1697 
  1698 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1699 
  1700 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1701   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1702 
  1703 * HOL/record: extensible records with schematic structural subtyping
  1704 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1705 still lacks various theorems and concrete record syntax;
  1706 
  1707 
  1708 *** HOLCF ***
  1709 
  1710 * removed "axioms" and "generated by" sections;
  1711 
  1712 * replaced "ops" section by extended "consts" section, which is capable of
  1713   handling the continuous function space "->" directly;
  1714 
  1715 * domain package:
  1716   . proves theorems immediately and stores them in the theory,
  1717   . creates hierachical name space,
  1718   . now uses normal mixfix annotations (instead of cinfix...),
  1719   . minor changes to some names and values (for consistency),
  1720   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1721   . separator between mutual domain defs: changed "," to "and",
  1722   . improved handling of sort constraints;  now they have to
  1723     appear on the left-hand side of the equations only;
  1724 
  1725 * fixed LAM <x,y,zs>.b syntax;
  1726 
  1727 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1728 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1729 
  1730 
  1731 *** FOL and ZF ***
  1732 
  1733 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1734   with `addloop' of the simplifier to faciliate case splitting in premises.
  1735 
  1736 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1737 in HOL, they strip ALL and --> from proved theorems;
  1738 
  1739 
  1740 
  1741 New in Isabelle94-8 (May 1997)
  1742 ------------------------------
  1743 
  1744 *** General Changes ***
  1745 
  1746 * new utilities to build / run / maintain Isabelle etc. (in parts
  1747 still somewhat experimental); old Makefiles etc. still functional;
  1748 
  1749 * new 'Isabelle System Manual';
  1750 
  1751 * INSTALL text, together with ./configure and ./build scripts;
  1752 
  1753 * reimplemented type inference for greater efficiency, better error
  1754 messages and clean internal interface;
  1755 
  1756 * prlim command for dealing with lots of subgoals (an easier way of
  1757 setting goals_limit);
  1758 
  1759 
  1760 *** Syntax ***
  1761 
  1762 * supports alternative (named) syntax tables (parser and pretty
  1763 printer); internal interface is provided by add_modesyntax(_i);
  1764 
  1765 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1766 be used in conjunction with the Isabelle symbol font; uses the
  1767 "symbols" syntax table;
  1768 
  1769 * added token_translation interface (may translate name tokens in
  1770 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1771 the current print_mode); IMPORTANT: user print translation functions
  1772 are responsible for marking newly introduced bounds
  1773 (Syntax.mark_boundT);
  1774 
  1775 * token translations for modes "xterm" and "xterm_color" that display
  1776 names in bold, underline etc. or colors (which requires a color
  1777 version of xterm);
  1778 
  1779 * infixes may now be declared with names independent of their syntax;
  1780 
  1781 * added typed_print_translation (like print_translation, but may
  1782 access type of constant);
  1783 
  1784 
  1785 *** Classical Reasoner ***
  1786 
  1787 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1788 some limitations.  Blast_tac...
  1789   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1790   + ignores elimination rules that don't have the correct format
  1791         (the conclusion MUST be a formula variable)
  1792   + ignores types, which can make HOL proofs fail
  1793   + rules must not require higher-order unification, e.g. apply_type in ZF
  1794     [message "Function Var's argument not a bound variable" relates to this]
  1795   + its proof strategy is more general but can actually be slower
  1796 
  1797 * substitution with equality assumptions no longer permutes other
  1798 assumptions;
  1799 
  1800 * minor changes in semantics of addafter (now called addaltern); renamed
  1801 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1802 (and access functions for it);
  1803 
  1804 * improved combination of classical reasoner and simplifier:
  1805   + functions for handling clasimpsets
  1806   + improvement of addss: now the simplifier is called _after_ the
  1807     safe steps.
  1808   + safe variant of addss called addSss: uses safe simplifications
  1809     _during_ the safe steps. It is more complete as it allows multiple
  1810     instantiations of unknowns (e.g. with slow_tac).
  1811 
  1812 *** Simplifier ***
  1813 
  1814 * added interface for simplification procedures (functions that
  1815 produce *proven* rewrite rules on the fly, depending on current
  1816 redex);
  1817 
  1818 * ordering on terms as parameter (used for ordered rewriting);
  1819 
  1820 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1821 
  1822 * the solver is now split into a safe and an unsafe part.
  1823 This should be invisible for the normal user, except that the
  1824 functions setsolver and addsolver have been renamed to setSolver and
  1825 addSolver; added safe_asm_full_simp_tac;
  1826 
  1827 
  1828 *** HOL ***
  1829 
  1830 * a generic induction tactic `induct_tac' which works for all datatypes and
  1831 also for type `nat';
  1832 
  1833 * a generic case distinction tactic `exhaust_tac' which works for all
  1834 datatypes and also for type `nat';
  1835 
  1836 * each datatype comes with a function `size';
  1837 
  1838 * patterns in case expressions allow tuple patterns as arguments to
  1839 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1840 
  1841 * primrec now also works with type nat;
  1842 
  1843 * recdef: a new declaration form, allows general recursive functions to be
  1844 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1845 
  1846 * the constant for negation has been renamed from "not" to "Not" to
  1847 harmonize with FOL, ZF, LK, etc.;
  1848 
  1849 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1850 infinite lists;
  1851 
  1852 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1853 
  1854 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1855 problems in commutative rings, using axiomatic type classes for + and *;
  1856 
  1857 * more examples in HOL/MiniML and HOL/Auth;
  1858 
  1859 * more default rewrite rules for quantifiers, union/intersection;
  1860 
  1861 * a new constant `arbitrary == @x.False';
  1862 
  1863 * HOLCF/IOA replaces old HOL/IOA;
  1864 
  1865 * HOLCF changes: derived all rules and arities
  1866   + axiomatic type classes instead of classes
  1867   + typedef instead of faking type definitions
  1868   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1869   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1870   + eliminated the types void, one, tr
  1871   + use unit lift and bool lift (with translations) instead of one and tr
  1872   + eliminated blift from Lift3.thy (use Def instead of blift)
  1873   all eliminated rules are derived as theorems --> no visible changes ;
  1874 
  1875 
  1876 *** ZF ***
  1877 
  1878 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1879 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1880 as ZF_cs addSIs [equalityI];
  1881 
  1882 
  1883 
  1884 New in Isabelle94-7 (November 96)
  1885 ---------------------------------
  1886 
  1887 * allowing negative levels (as offsets) in prlev and choplev;
  1888 
  1889 * super-linear speedup for large simplifications;
  1890 
  1891 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1892 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1893 FAIL); can suppress it using the command Delsimps (ex_simps @
  1894 all_simps); De Morgan laws are also now included, by default;
  1895 
  1896 * improved printing of ==>  :  ~:
  1897 
  1898 * new object-logic "Sequents" adds linear logic, while replacing LK
  1899 and Modal (thanks to Sara Kalvala);
  1900 
  1901 * HOL/Auth: correctness proofs for authentication protocols;
  1902 
  1903 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1904 examples on HOL/Auth);
  1905 
  1906 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1907 the rewriter and classical reasoner simultaneously;
  1908 
  1909 * function uresult no longer returns theorems in "standard" format;
  1910 regain previous version by: val uresult = standard o uresult;
  1911 
  1912 
  1913 
  1914 New in Isabelle94-6
  1915 -------------------
  1916 
  1917 * oracles -- these establish an interface between Isabelle and trusted
  1918 external reasoners, which may deliver results as theorems;
  1919 
  1920 * proof objects (in particular record all uses of oracles);
  1921 
  1922 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1923 
  1924 * "constdefs" section in theory files;
  1925 
  1926 * "primrec" section (HOL) no longer requires names;
  1927 
  1928 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1929 
  1930 
  1931 
  1932 New in Isabelle94-5
  1933 -------------------
  1934 
  1935 * reduced space requirements;
  1936 
  1937 * automatic HTML generation from theories;
  1938 
  1939 * theory files no longer require "..." (quotes) around most types;
  1940 
  1941 * new examples, including two proofs of the Church-Rosser theorem;
  1942 
  1943 * non-curried (1994) version of HOL is no longer distributed;
  1944 
  1945 
  1946 
  1947 New in Isabelle94-4
  1948 -------------------
  1949 
  1950 * greatly reduced space requirements;
  1951 
  1952 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1953 
  1954 * searchable theorem database (see the section "Retrieving theorems" on
  1955 page 8 of the Reference Manual);
  1956 
  1957 * new examples, including Grabczewski's monumental case study of the
  1958 Axiom of Choice;
  1959 
  1960 * The previous version of HOL renamed to Old_HOL;
  1961 
  1962 * The new version of HOL (previously called CHOL) uses a curried syntax
  1963 for functions.  Application looks like f a b instead of f(a,b);
  1964 
  1965 * Mutually recursive inductive definitions finally work in HOL;
  1966 
  1967 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1968 translates to the operator "split";
  1969 
  1970 
  1971 
  1972 New in Isabelle94-3
  1973 -------------------
  1974 
  1975 * new infix operator, addss, allowing the classical reasoner to
  1976 perform simplification at each step of its search.  Example:
  1977         fast_tac (cs addss ss)
  1978 
  1979 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1980 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1981 look like (a,b) instead of <a,b>;
  1982 
  1983 * PLEASE NOTE: CHOL will eventually replace HOL!
  1984 
  1985 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1986 It translates to the operator "split".  A new theory of integers is available;
  1987 
  1988 * In ZF, integer numerals now denote two's-complement binary integers.
  1989 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1990 
  1991 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1992 of the Axiom of Choice;
  1993 
  1994 
  1995 
  1996 New in Isabelle94-2
  1997 -------------------
  1998 
  1999 * Significantly faster resolution;
  2000 
  2001 * the different sections in a .thy file can now be mixed and repeated
  2002 freely;
  2003 
  2004 * Database of theorems for FOL, HOL and ZF.  New
  2005 commands including qed, qed_goal and bind_thm store theorems in the database.
  2006 
  2007 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2008 a given theory (thms_of), or find out what theory a theorem was proved in
  2009 (theory_of_thm);
  2010 
  2011 * Bugs fixed in the inductive definition and datatype packages;
  2012 
  2013 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2014 and HOL_dup_cs obsolete;
  2015 
  2016 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2017 have been removed;
  2018 
  2019 * Simpler definition of function space in ZF;
  2020 
  2021 * new results about cardinal and ordinal arithmetic in ZF;
  2022 
  2023 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2024 types;
  2025 
  2026 
  2027 $Id$