NEWS
author wenzelm
Mon Sep 11 18:00:47 2000 +0200 (2000-09-11)
changeset 9924 3370f6aa3200
parent 9908 7c7ff65b6846
child 9937 431c96ac997e
permissions -rw-r--r--
updated;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in this Isabelle version
     6 ----------------------------
     7 
     8 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     9 
    10 * HOL: simplification of natural numbers is much changed; to partly
    11 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
    12 issue the following ML commands:
    13 
    14   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
    15   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
    16 
    17 * HOL: 0 is now overloaded, so the type constraint ::nat may sometimes be
    18 needed;
    19 
    20 * HOL: the constant for f``x is now "image" rather than "op ``";
    21 
    22 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
    23 product is now "<*>" instead of "Times"; the lexicographic product is
    24 now "<*lex*>" instead of "**";
    25 
    26 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    27 
    28 * HOL: simplification no longer dives into case-expressions;
    29 
    30 * HOL: the recursion equations generated by 'recdef' are now called
    31 f.simps instead of f.rules;
    32 
    33 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
    34 main HOL, but was unused); should better use HOL's datatype package
    35 anyway;
    36 
    37 * HOL: removed obsolete theorem binding expand_if (refer to split_if
    38 instead);
    39 
    40 * HOL: less_induct is renamed nat_less_induct
    41 
    42 * HOL/Real: "rabs" replaced by overloaded "abs" function;
    43 
    44 * HOL/ML: even fewer consts are declared as global (see theories Ord,
    45 Lfp, Gfp, WF); this only affects ML packages that refer to const names
    46 internally;
    47 
    48 * HOL, ZF: syntax for quotienting wrt an equivalence relation changed
    49 from A/r to A//r;
    50 
    51 * HOL: qed_spec_mp now also removes bounded ALL;
    52 
    53 * ZF: new treatment of arithmetic (nat & int) may break some old proofs;
    54 
    55 * Isar/Provers: intro/elim/dest attributes: changed
    56 intro/intro!/intro!!  flags to intro!/intro/intro? (in most cases, one
    57 should have to change intro!! to intro? only);
    58 
    59 * Isar: changed syntax of local blocks from {{ }} to { };
    60 
    61 * Isar: renamed 'RS' attribute to 'THEN';
    62 
    63 * Isar: renamed some attributes (rulify -> rulified, elimify -> elimified, ...);
    64 
    65 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
    66 
    67 * Provers: strengthened force_tac by using new first_best_tac;
    68 
    69 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
    70   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
    71 use instead the strong form,
    72   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
    73 In HOL, FOL and ZF the function cla_make_elim will create such rules
    74 from destruct-rules;
    75 
    76 * Provers: safe_asm_full_simp_tac is no longer in the simplifier signature. Use
    77   val safe_asm_full_simp_tac = generic_simp_tac true (true,true,true);
    78   if required.
    79 
    80 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
    81 timing flag supersedes proof_timing and Toplevel.trace;
    82 
    83 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    84 
    85 * ML: PureThy.add_defs gets additional argument to indicate potential
    86 overloading (usually false);
    87 
    88 * LaTeX: several changes of isabelle.sty;
    89 
    90 
    91 *** Document preparation ***
    92 
    93 * formal comments (text blocks etc.) in new-style theories may now
    94 contain antiquotations of thm/prop/term/typ/text to be presented
    95 according to latex print mode; concrete syntax is like this:
    96 @{term[show_types] "f(x) = a + x"};
    97 
    98 * isatool mkdir provides easy setup of Isabelle session directories,
    99 including proper document sources;
   100 
   101 * generated LaTeX sources are now deleted after successful run
   102 (isatool document -c); may retain a copy somewhere else via -D option
   103 of isatool usedir;
   104 
   105 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   106 style files, achieving self-contained LaTeX sources;
   107 
   108 * old-style theories now produce (crude) LaTeX output as well;
   109 
   110 * browser info session directories are now self-contained (may be put
   111 on WWW server seperately); improved graphs of nested sessions; removed
   112 graph for 'all sessions';
   113 
   114 * several improvements in isabelle.sty; \isabellestyle{it} produces
   115 near math mode output; \isamarkupheader is now \section by default;
   116 
   117 
   118 *** Isar ***
   119 
   120 * Pure: local results and corresponding term bindings are now subject
   121 to Hindley-Milner polymorphism (similar to ML); this accommodates
   122 incremental type-inference nicely;
   123 
   124 * Pure: new derived language element 'obtain' supports generalized
   125 existence reasoning;
   126 
   127 * Pure: new calculational elements 'moreover' and 'ultimately' support
   128 accumulation of results, without applying any rules yet;
   129 
   130 * Pure: scalable support for case-analysis type proofs: new 'case'
   131 language element refers to local contexts symbolically, as produced by
   132 certain proof methods; internally, case names are attached to theorems
   133 as "tags";
   134 
   135 * Pure: theory command 'hide' removes declarations from
   136 class/type/const name spaces;
   137 
   138 * Pure: theory command 'defs' supports option "(overloaded)" to
   139 indicate potential overloading;
   140 
   141 * Pure: changed syntax of local blocks from {{ }} to { };
   142 
   143 * Pure: renamed 'RS' attribute to 'THEN';
   144 
   145 * Pure: syntax of sorts made 'inner', i.e. have to write "{a, b, c}"
   146 instead of {a, b, c};
   147 
   148 * Pure now provides its own version of intro/elim/dest attributes;
   149 useful for building new logics, but beware of confusion with the
   150 version in Provers/classical;
   151 
   152 * Pure: the local context of (non-atomic) goals is provided via case
   153 name 'antecedent';
   154 
   155 * Pure: removed obsolete 'transfer' attribute (transfer of thms to the
   156 current context is now done automatically);
   157 
   158 * Pure: theory command 'method_setup' provides a simple interface for
   159 definining proof methods in ML;
   160 
   161 * Provers: 'simp' method now supports 'cong' modifiers;
   162 
   163 * Provers: hypsubst support; also plain subst and symmetric attribute
   164 (the latter supercedes [RS sym]);
   165 
   166 * Provers: splitter support (via 'split' attribute and 'simp' method
   167 modifier); 'simp' method: 'only:' modifier removes loopers as well
   168 (including splits);
   169 
   170 * Provers: added 'fastsimp' and 'clarsimp' methods (combination of
   171 Simplifier and Classical reasoner);
   172 
   173 * Provers: added 'arith_split' attribute;
   174 
   175 * HOL: new proof method 'cases' and improved version of 'induct' now
   176 support named cases; major packages (inductive, datatype, primrec,
   177 recdef) support case names and properly name parameters;
   178 
   179 * HOL: removed 'case_split' thm binding, should use 'cases' proof
   180 method anyway;
   181 
   182 * HOL: removed obsolete expand_if = split_if; theorems if_splits =
   183 split_if split_if_asm; datatype package provides theorems foo.splits =
   184 foo.split foo.split_asm for each datatype;
   185 
   186 * HOL/Calculation: new rules for substitution in inequalities
   187 (monotonicity conditions are extracted to be proven at end);
   188 
   189 * HOL/inductive: rename "intrs" to "intros" (potential
   190 INCOMPATIBILITY); emulation of mk_cases feature for proof scripts:
   191 'inductive_cases' command and 'ind_cases' method; NOTE: use (cases
   192 (simplified)) method in proper proofs;
   193 
   194 * Provers: intro/elim/dest attributes: changed intro/intro!/intro!!
   195 flags to intro!/intro/intro? (in most cases, one should have to change
   196 intro!! to intro? only);
   197 
   198 * names of theorems etc. may be natural numbers as well;
   199 
   200 * 'pr' command: optional arguments for goals_limit and
   201 ProofContext.prems_limit; no longer prints theory contexts, but only
   202 proof states;
   203 
   204 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   205 additional print modes to be specified; e.g. "pr(latex)" will print
   206 proof state according to the Isabelle LaTeX style;
   207 
   208 * improved support for emulating tactic scripts, including proof
   209 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   210 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   211 (for HOL datatypes);
   212 
   213 * simplified (more robust) goal selection of proof methods: 1st goal,
   214 all goals, or explicit goal specifier (tactic emulation); thus 'proof
   215 method scripts' have to be in depth-first order;
   216 
   217 * tuned 'let' syntax: replaced 'as' keyword by 'and';
   218 
   219 * removed 'help' command, which hasn't been too helpful anyway; should
   220 instead use individual commands for printing items (print_commands,
   221 print_methods etc.);
   222 
   223 * added 'nothing' --- the empty list of theorems;
   224 
   225 
   226 *** HOL ***
   227 
   228 * HOL/Lambda: converted into new-style theory and document;
   229 
   230 * HOL/Algebra: new theory of rings and univariate polynomials, by
   231 Clemens Ballarin;
   232 
   233 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
   234 Arithmetic, by Thomas M Rasmussen;
   235 
   236 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
   237 basically a generalized version of de-Bruijn representation; very
   238 useful in avoiding lifting of operations;
   239 
   240 * HOL/NumberTheory: Chinese Remainder Theorem, Fermat/Euler Theorem, Wilson's
   241 Theorem, by Thomas M Rasmussen;
   242 
   243 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog;
   244 
   245 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   246 
   247 * HOL/record: added general record equality rule to simpset; fixed
   248 select-update simplification procedure to handle extended records as
   249 well; admit "r" as field name;
   250 
   251 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   252 other numeric types and also as the identity of groups, rings, etc.;
   253 
   254 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   255 Types nat and int belong to this axclass;
   256 
   257 * greatly improved simplification involving numerals of type nat, int, real:
   258    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   259    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   260   two terms #m*u and #n*u are replaced by #(m+n)*u
   261     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   262   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   263     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   264 
   265 * HOL: meson_tac is available (previously in ex/meson.ML).  It is a powerful
   266    prover for predicate logic but knows nothing of clasets.  For examples of
   267    what it can do, see ex/mesontest.ML and ex/mesontest2.ML;
   268 
   269 * HOL: new version of "case_tac" subsumes both boolean case split and
   270 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   271 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   272 
   273 * HOL: simplification no longer dives into case-expressions: only the
   274 selector expression is simplified, but not the remaining arms. To
   275 enable full simplification of case-expressions for datatype t, you
   276 need to remove t.weak_case_cong from the simpset, either permanently
   277 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   278 
   279 * HOL/recdef: the recursion equations generated by 'recdef' for
   280 function 'f' are now called f.simps instead of f.rules; if all
   281 termination conditions are proved automatically, these simplification
   282 rules are added to the simpset, as in primrec; rules may be named
   283 individually as well, resulting in a separate list of theorems for
   284 each equation;
   285 
   286 * HOL/While is a new theory that provides a while-combinator. It
   287 permits the definition of tail-recursive functions without the
   288 provision of a termination measure. The latter is necessary once the
   289 invariant proof rule for while is applied.
   290 
   291 * HOL: new (overloaded) notation for the set of elements below/above some
   292 element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   293 
   294 * HOL: theorems impI, allI, ballI bound as "strip";
   295 
   296 * new tactic induct_thm_tac: thm -> string -> int -> tactic
   297 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   298 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   299 
   300 * new functions rulify/rulify_no_asm: thm -> thm for turning outer
   301 -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   302 
   303 * theory Sexp now in HOL/Induct examples (it used to be part of main
   304 HOL, but was unused);
   305 
   306 * fewer consts declared as global (e.g. have to refer to "Lfp.lfp"
   307 instead of "lfp" internally; affects ML packages only);
   308 
   309 * tuned AST representation of nested pairs, avoiding bogus output in
   310 case of overlap with user translations (e.g. judgements over tuples);
   311 
   312 
   313 *** ZF ***
   314 
   315 * simplification automatically cancels common terms in arithmetic expressions
   316 over nat and int;
   317 
   318 * new treatment of nat to minimize type-checking: all operators coerce their 
   319 operands to a natural number using the function natify, making the algebraic
   320 laws unconditional;
   321 
   322 * as above, for int: operators coerce their operands to an integer using the
   323 function intify;
   324 
   325 * the integer library now contains many of the usual laws for the orderings, 
   326 including $<=, and monotonicity laws for $+ and $*; 
   327 
   328 * new example ZF/ex/NatSum to demonstrate integer arithmetic simplification;
   329 
   330 *** FOL & ZF ***
   331 
   332 * AddIffs now available, giving theorems of the form P<->Q to the
   333 simplifier and classical reasoner simultaneously;
   334 
   335 
   336 *** General ***
   337 
   338 * Provers: blast(_tac) now handles actual object-logic rules as
   339 assumptions; note that auto(_tac) uses blast(_tac) internally as well;
   340 
   341 * Provers: Simplifier.easy_setup provides a fast path to basic
   342 Simplifier setup for new object-logics;
   343 
   344 * Pure: AST translation rules no longer require constant head on LHS;
   345 
   346 * Pure: improved name spaces: ambiguous output is qualified; support
   347 for hiding of names;
   348 
   349 * system: compression of ML heaps images may now be controlled via -c
   350 option of isabelle and isatool usedir (currently only observed by
   351 Poly/ML);
   352 
   353 * system: provide TAGS file for Isabelle sources;
   354 
   355 * settings: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   356 XSYMBOL_HOME; no longer need to do manual configuration in most
   357 situations;
   358 
   359 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   360 order;
   361 
   362 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   363 timing flag supersedes proof_timing and Toplevel.trace;
   364 
   365 * ML: PureThy.add_defs gets additional argument to indicate potential
   366 overloading (usually false);
   367 
   368 * ML: new combinators |>> and |>>> for incremental transformations
   369 with secondary results (e.g. certain theory extensions):
   370 
   371 
   372 
   373 New in Isabelle99 (October 1999)
   374 --------------------------------
   375 
   376 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   377 
   378 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   379 are no longer simplified.  (This allows the simplifier to unfold recursive
   380 functional programs.)  To restore the old behaviour, declare
   381 
   382     Delcongs [if_weak_cong];
   383 
   384 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   385 complement;
   386 
   387 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   388 
   389 * HOL/datatype: mutual_induct_tac no longer exists --
   390   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   391 
   392 * HOL/typedef: fixed type inference for representing set; type
   393 arguments now have to occur explicitly on the rhs as type constraints;
   394 
   395 * ZF: The con_defs part of an inductive definition may no longer refer
   396 to constants declared in the same theory;
   397 
   398 * HOL, ZF: the function mk_cases, generated by the inductive
   399 definition package, has lost an argument.  To simplify its result, it
   400 uses the default simpset instead of a supplied list of theorems.
   401 
   402 * HOL/List: the constructors of type list are now Nil and Cons;
   403 
   404 * Simplifier: the type of the infix ML functions
   405         setSSolver addSSolver setSolver addSolver
   406 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   407 for packaging solvers. A solver is created via
   408         mk_solver: string -> (thm list -> int -> tactic) -> solver
   409 where the string argument is only a comment.
   410 
   411 
   412 *** Proof tools ***
   413 
   414 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   415 decision procedure for linear arithmetic. Currently it is used for
   416 types `nat', `int', and `real' in HOL (see below); it can, should and
   417 will be instantiated for other types and logics as well.
   418 
   419 * The simplifier now accepts rewrite rules with flexible heads, eg
   420      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   421   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   422   matching.
   423 
   424 
   425 *** General ***
   426 
   427 * New Isabelle/Isar subsystem provides an alternative to traditional
   428 tactical theorem proving; together with the ProofGeneral/isar user
   429 interface it offers an interactive environment for developing human
   430 readable proof documents (Isar == Intelligible semi-automated
   431 reasoning); for further information see isatool doc isar-ref,
   432 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   433 
   434 * improved and simplified presentation of theories: better HTML markup
   435 (including colors), graph views in several sizes; isatool usedir now
   436 provides a proper interface for user theories (via -P option); actual
   437 document preparation based on (PDF)LaTeX is available as well (for
   438 new-style theories only); see isatool doc system for more information;
   439 
   440 * native support for Proof General, both for classic Isabelle and
   441 Isabelle/Isar;
   442 
   443 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   444 using the graph browser tool;
   445 
   446 * Isabelle manuals now also available as PDF;
   447 
   448 * theory loader rewritten from scratch (may not be fully
   449 bug-compatible); old loadpath variable has been replaced by show_path,
   450 add_path, del_path, reset_path functions; new operations such as
   451 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   452 isatool doc ref);
   453 
   454 * improved isatool install: option -k creates KDE application icon,
   455 option -p DIR installs standalone binaries;
   456 
   457 * added ML_PLATFORM setting (useful for cross-platform installations);
   458 more robust handling of platform specific ML images for SML/NJ;
   459 
   460 * the settings environment is now statically scoped, i.e. it is never
   461 created again in sub-processes invoked from isabelle, isatool, or
   462 Isabelle;
   463 
   464 * path element specification '~~' refers to '$ISABELLE_HOME';
   465 
   466 * in locales, the "assumes" and "defines" parts may be omitted if
   467 empty;
   468 
   469 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   470 long arrows);
   471 
   472 * new print_mode "HTML";
   473 
   474 * new flag show_tags controls display of tags of theorems (which are
   475 basically just comments that may be attached by some tools);
   476 
   477 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   478 mode and goal output format:
   479 
   480 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   481 244c244
   482 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   483 ---
   484 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   485 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   486 181c181
   487 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   488 ---
   489 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   490 
   491 * function bind_thms stores lists of theorems (cf. bind_thm);
   492 
   493 * new shorthand tactics ftac, eatac, datac, fatac;
   494 
   495 * qed (and friends) now accept "" as result name; in that case the
   496 theorem is not stored, but proper checks and presentation of the
   497 result still apply;
   498 
   499 * theorem database now also indexes constants "Trueprop", "all",
   500 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   501 
   502 
   503 *** HOL ***
   504 
   505 ** HOL arithmetic **
   506 
   507 * There are now decision procedures for linear arithmetic over nat and
   508 int:
   509 
   510 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   511 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   512 are treated as atomic; subformulae not involving type `nat' or `int'
   513 are ignored; quantified subformulae are ignored unless they are
   514 positive universal or negative existential. The tactic has to be
   515 invoked by hand and can be a little bit slow. In particular, the
   516 running time is exponential in the number of occurrences of `min' and
   517 `max', and `-' on `nat'.
   518 
   519 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   520 (negated) (in)equalities among the premises and the conclusion into
   521 account (i.e. no compound formulae) and does not know about `min' and
   522 `max', and `-' on `nat'. It is fast and is used automatically by the
   523 simplifier.
   524 
   525 NB: At the moment, these decision procedures do not cope with mixed
   526 nat/int formulae where the two parts interact, such as `m < n ==>
   527 int(m) < int(n)'.
   528 
   529 * HOL/Numeral provides a generic theory of numerals (encoded
   530 efficiently as bit strings); setup for types nat/int/real is in place;
   531 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   532 int, existing theories and proof scripts may require a few additional
   533 type constraints;
   534 
   535 * integer division and remainder can now be performed on constant
   536 arguments;
   537 
   538 * many properties of integer multiplication, division and remainder
   539 are now available;
   540 
   541 * An interface to the Stanford Validity Checker (SVC) is available through the
   542 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   543 are proved automatically.  SVC must be installed separately, and its results
   544 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   545 invocation of the underlying oracle).  For SVC see
   546   http://verify.stanford.edu/SVC
   547 
   548 * IsaMakefile: the HOL-Real target now builds an actual image;
   549 
   550 
   551 ** HOL misc **
   552 
   553 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   554 (in Isabelle/Isar) -- by Gertrud Bauer;
   555 
   556 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   557 analysis for assembly languages with subtypes;
   558 
   559 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   560 -- avoids syntactic ambiguities and treats state, transition, and
   561 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   562 changed syntax and (many) tactics;
   563 
   564 * HOL/inductive: Now also handles more general introduction rules such
   565   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   566   theorems are now maintained within the theory (maintained via the
   567   "mono" attribute);
   568 
   569 * HOL/datatype: Now also handles arbitrarily branching datatypes
   570   (using function types) such as
   571 
   572   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   573 
   574 * HOL/record: record_simproc (part of the default simpset) takes care
   575 of selectors applied to updated records; record_split_tac is no longer
   576 part of the default claset; update_defs may now be removed from the
   577 simpset in many cases; COMPATIBILITY: old behavior achieved by
   578 
   579   claset_ref () := claset() addSWrapper record_split_wrapper;
   580   Delsimprocs [record_simproc]
   581 
   582 * HOL/typedef: fixed type inference for representing set; type
   583 arguments now have to occur explicitly on the rhs as type constraints;
   584 
   585 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   586 names rather than an ML expression;
   587 
   588 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   589 supplied later.  Program schemes can be defined, such as
   590     "While B C s = (if B s then While B C (C s) else s)"
   591 where the well-founded relation can be chosen after B and C have been given.
   592 
   593 * HOL/List: the constructors of type list are now Nil and Cons;
   594 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   595 course, ML tools referring to List.list.op # etc. have to be adapted;
   596 
   597 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   598 disabled by default; run isabelle with option -m HOL to get back to
   599 the original Gordon/HOL-style output;
   600 
   601 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   602 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   603 
   604 * HOL basic syntax simplified (more orthogonal): all variants of
   605 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   606 Eps operator is provided as well: "SOME x. P[x]";
   607 
   608 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   609 
   610 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   611 thus available for user theories;
   612 
   613 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   614 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   615 time;
   616 
   617 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   618 several times and then mp;
   619 
   620 
   621 *** LK ***
   622 
   623 * the notation <<...>> is now available as a notation for sequences of
   624 formulas;
   625 
   626 * the simplifier is now installed
   627 
   628 * the axiom system has been generalized (thanks to Soren Heilmann)
   629 
   630 * the classical reasoner now has a default rule database
   631 
   632 
   633 *** ZF ***
   634 
   635 * new primrec section allows primitive recursive functions to be given
   636 directly (as in HOL) over datatypes and the natural numbers;
   637 
   638 * new tactics induct_tac and exhaust_tac for induction (or case
   639 analysis) over datatypes and the natural numbers;
   640 
   641 * the datatype declaration of type T now defines the recursor T_rec;
   642 
   643 * simplification automatically does freeness reasoning for datatype
   644 constructors;
   645 
   646 * automatic type-inference, with AddTCs command to insert new
   647 type-checking rules;
   648 
   649 * datatype introduction rules are now added as Safe Introduction rules
   650 to the claset;
   651 
   652 * the syntax "if P then x else y" is now available in addition to
   653 if(P,x,y);
   654 
   655 
   656 *** Internal programming interfaces ***
   657 
   658 * tuned simplifier trace output; new flag debug_simp;
   659 
   660 * structures Vartab / Termtab (instances of TableFun) offer efficient
   661 tables indexed by indexname_ord / term_ord (compatible with aconv);
   662 
   663 * AxClass.axclass_tac lost the theory argument;
   664 
   665 * tuned current_goals_markers semantics: begin / end goal avoids
   666 printing empty lines;
   667 
   668 * removed prs and prs_fn hook, which was broken because it did not
   669 include \n in its semantics, forcing writeln to add one
   670 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   671 string -> unit if you really want to output text without newline;
   672 
   673 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   674 plain output, interface builders may have to enable 'isabelle_font'
   675 mode to get Isabelle font glyphs as before;
   676 
   677 * refined token_translation interface; INCOMPATIBILITY: output length
   678 now of type real instead of int;
   679 
   680 * theory loader actions may be traced via new ThyInfo.add_hook
   681 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   682 your own database of information attached to *whole* theories -- as
   683 opposed to intra-theory data slots offered via TheoryDataFun;
   684 
   685 * proper handling of dangling sort hypotheses (at last!);
   686 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   687 extra sort hypotheses that can be witnessed from the type signature;
   688 the force_strip_shyps flag is gone, any remaining shyps are simply
   689 left in the theorem (with a warning issued by strip_shyps_warning);
   690 
   691 
   692 
   693 New in Isabelle98-1 (October 1998)
   694 ----------------------------------
   695 
   696 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   697 
   698 * several changes of automated proof tools;
   699 
   700 * HOL: major changes to the inductive and datatype packages, including
   701 some minor incompatibilities of theory syntax;
   702 
   703 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   704 called `inj_on';
   705 
   706 * HOL: removed duplicate thms in Arith:
   707   less_imp_add_less  should be replaced by  trans_less_add1
   708   le_imp_add_le      should be replaced by  trans_le_add1
   709 
   710 * HOL: unary minus is now overloaded (new type constraints may be
   711 required);
   712 
   713 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   714 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   715 now taken as an integer constant.
   716 
   717 * Pure: ML function 'theory_of' renamed to 'theory';
   718 
   719 
   720 *** Proof tools ***
   721 
   722 * Simplifier:
   723   1. Asm_full_simp_tac is now more aggressive.
   724      1. It will sometimes reorient premises if that increases their power to
   725         simplify.
   726      2. It does no longer proceed strictly from left to right but may also
   727         rotate premises to achieve further simplification.
   728      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   729      old Asm_full_simp_tac in that it does not rotate premises.
   730   2. The simplifier now knows a little bit about nat-arithmetic.
   731 
   732 * Classical reasoner: wrapper mechanism for the classical reasoner now
   733 allows for selected deletion of wrappers, by introduction of names for
   734 wrapper functionals.  This implies that addbefore, addSbefore,
   735 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   736 and that adding two tactics with the same name overwrites the first
   737 one (emitting a warning).
   738   type wrapper = (int -> tactic) -> (int -> tactic)
   739   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   740   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   741   delWrapper, delSWrapper: claset *  string            -> claset
   742   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   743 
   744 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   745 semantics; addbefore now affects only the unsafe part of step_tac
   746 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   747 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   748 by Force_tac;
   749 
   750 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   751 compWrapper; added safe wrapper (and access functions for it);
   752 
   753 * HOL/split_all_tac is now much faster and fails if there is nothing
   754 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   755 and the names of the automatically generated variables have changed.
   756 split_all_tac has moved within claset() from unsafe wrappers to safe
   757 wrappers, which means that !!-bound variables are split much more
   758 aggressively, and safe_tac and clarify_tac now split such variables.
   759 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   760 Note: the same holds for record_split_tac, which does the job of
   761 split_all_tac for record fields.
   762 
   763 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   764 permanently to the default simpset using Addsplits just like
   765 Addsimps. They can be removed via Delsplits just like
   766 Delsimps. Lower-case versions are also available.
   767 
   768 * HOL/Simplifier: The rule split_if is now part of the default
   769 simpset. This means that the simplifier will eliminate all occurrences
   770 of if-then-else in the conclusion of a goal. To prevent this, you can
   771 either remove split_if completely from the default simpset by
   772 `Delsplits [split_if]' or remove it in a specific call of the
   773 simplifier using `... delsplits [split_if]'.  You can also add/delete
   774 other case splitting rules to/from the default simpset: every datatype
   775 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   776 t is the name of the datatype).
   777 
   778 * Classical reasoner / Simplifier combination: new force_tac (and
   779 derivatives Force_tac, force) combines rewriting and classical
   780 reasoning (and whatever other tools) similarly to auto_tac, but is
   781 aimed to solve the given subgoal completely.
   782 
   783 
   784 *** General ***
   785 
   786 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   787 and `goalw': the theory is no longer needed as an explicit argument -
   788 the current theory context is used; assumptions are no longer returned
   789 at the ML-level unless one of them starts with ==> or !!; it is
   790 recommended to convert to these new commands using isatool fixgoal
   791 (backup your sources first!);
   792 
   793 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   794 the current theory context, and 'theory' to lookup stored theories;
   795 
   796 * new theory section 'locale' for declaring constants, assumptions and
   797 definitions that have local scope;
   798 
   799 * new theory section 'nonterminals' for purely syntactic types;
   800 
   801 * new theory section 'setup' for generic ML setup functions
   802 (e.g. package initialization);
   803 
   804 * the distribution now includes Isabelle icons: see
   805 lib/logo/isabelle-{small,tiny}.xpm;
   806 
   807 * isatool install - install binaries with absolute references to
   808 ISABELLE_HOME/bin;
   809 
   810 * isatool logo -- create instances of the Isabelle logo (as EPS);
   811 
   812 * print mode 'emacs' reserved for Isamode;
   813 
   814 * support multiple print (ast) translations per constant name;
   815 
   816 * theorems involving oracles are now printed with a suffixed [!];
   817 
   818 
   819 *** HOL ***
   820 
   821 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   822 
   823 * HOL/inductive package reorganized and improved: now supports mutual
   824 definitions such as
   825 
   826   inductive EVEN ODD
   827     intrs
   828       null "0 : EVEN"
   829       oddI "n : EVEN ==> Suc n : ODD"
   830       evenI "n : ODD ==> Suc n : EVEN"
   831 
   832 new theorem list "elims" contains an elimination rule for each of the
   833 recursive sets; inductive definitions now handle disjunctive premises
   834 correctly (also ZF);
   835 
   836 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   837 "mutual_induct" no longer exists - the induction rule is always
   838 contained in "induct";
   839 
   840 
   841 * HOL/datatype package re-implemented and greatly improved: now
   842 supports mutually recursive datatypes such as
   843 
   844   datatype
   845     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   846             | SUM ('a aexp) ('a aexp)
   847             | DIFF ('a aexp) ('a aexp)
   848             | NUM 'a
   849   and
   850     'a bexp = LESS ('a aexp) ('a aexp)
   851             | AND ('a bexp) ('a bexp)
   852             | OR ('a bexp) ('a bexp)
   853 
   854 as well as indirectly recursive datatypes such as
   855 
   856   datatype
   857     ('a, 'b) term = Var 'a
   858                   | App 'b ((('a, 'b) term) list)
   859 
   860 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   861 induction on mutually / indirectly recursive datatypes.
   862 
   863 Primrec equations are now stored in theory and can be accessed via
   864 <function_name>.simps.
   865 
   866 INCOMPATIBILITIES:
   867 
   868   - Theories using datatypes must now have theory Datatype as an
   869     ancestor.
   870   - The specific <typename>.induct_tac no longer exists - use the
   871     generic induct_tac instead.
   872   - natE has been renamed to nat.exhaust - use exhaust_tac
   873     instead of res_inst_tac ... natE. Note that the variable
   874     names in nat.exhaust differ from the names in natE, this
   875     may cause some "fragile" proofs to fail.
   876   - The theorems split_<typename>_case and split_<typename>_case_asm
   877     have been renamed to <typename>.split and <typename>.split_asm.
   878   - Since default sorts of type variables are now handled correctly,
   879     some datatype definitions may have to be annotated with explicit
   880     sort constraints.
   881   - Primrec definitions no longer require function name and type
   882     of recursive argument.
   883 
   884 Consider using isatool fixdatatype to adapt your theories and proof
   885 scripts to the new package (backup your sources first!).
   886 
   887 
   888 * HOL/record package: considerably improved implementation; now
   889 includes concrete syntax for record types, terms, updates; theorems
   890 for surjective pairing and splitting !!-bound record variables; proof
   891 support is as follows:
   892 
   893   1) standard conversions (selectors or updates applied to record
   894 constructor terms) are part of the standard simpset;
   895 
   896   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   897 made part of standard simpset and claset via addIffs;
   898 
   899   3) a tactic for record field splitting (record_split_tac) is part of
   900 the standard claset (addSWrapper);
   901 
   902 To get a better idea about these rules you may retrieve them via
   903 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   904 the name of your record type.
   905 
   906 The split tactic 3) conceptually simplifies by the following rule:
   907 
   908   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   909 
   910 Thus any record variable that is bound by meta-all will automatically
   911 blow up into some record constructor term, consequently the
   912 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   913 solve record problems automatically.
   914 
   915 
   916 * reorganized the main HOL image: HOL/Integ and String loaded by
   917 default; theory Main includes everything;
   918 
   919 * automatic simplification of integer sums and comparisons, using cancellation;
   920 
   921 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   922 
   923 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   924 
   925 * many new identities for unions, intersections, set difference, etc.;
   926 
   927 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   928 called split_if, split_split, split_sum_case and split_nat_case (to go
   929 with add/delsplits);
   930 
   931 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   932 (?x::unit) = (); this is made part of the default simpset, which COULD
   933 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   934 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   935 unit_abs_eta_conv is added in order to counter the effect of
   936 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   937 %u.f();
   938 
   939 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   940 makes more sense);
   941 
   942 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   943   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   944   disjointness reasoning but breaking a few old proofs.
   945 
   946 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   947 to 'converse' from 'inverse' (for compatibility with ZF and some
   948 literature);
   949 
   950 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   951 the well-founded relation;
   952 
   953 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   954     Compl A.  The "Compl" syntax remains available as input syntax for this
   955     release ONLY.
   956 
   957 * HOL/Update: new theory of function updates:
   958     f(a:=b) == %x. if x=a then b else f x
   959 may also be iterated as in f(a:=b,c:=d,...);
   960 
   961 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   962 
   963 * HOL/List:
   964   - new function list_update written xs[i:=v] that updates the i-th
   965     list position. May also be iterated as in xs[i:=a,j:=b,...].
   966   - new function `upt' written [i..j(] which generates the list
   967     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   968     bound write [i..j], which is a shorthand for [i..j+1(].
   969   - new lexicographic orderings and corresponding wellfoundedness theorems.
   970 
   971 * HOL/Arith:
   972   - removed 'pred' (predecessor) function;
   973   - generalized some theorems about n-1;
   974   - many new laws about "div" and "mod";
   975   - new laws about greatest common divisors (see theory ex/Primes);
   976 
   977 * HOL/Relation: renamed the relational operator r^-1 "converse"
   978 instead of "inverse";
   979 
   980 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   981   of the multiset ordering;
   982 
   983 * directory HOL/Real: a construction of the reals using Dedekind cuts
   984   (not included by default);
   985 
   986 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   987 
   988 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   989   programs, i.e. different program variables may have different types.
   990 
   991 * calling (stac rew i) now fails if "rew" has no effect on the goal
   992   [previously, this check worked only if the rewrite rule was unconditional]
   993   Now rew can involve either definitions or equalities (either == or =).
   994 
   995 
   996 *** ZF ***
   997 
   998 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   999   only the theorems proved on ZF.ML;
  1000 
  1001 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1002   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1003   disjointness reasoning but breaking a few old proofs.
  1004 
  1005 * ZF/Update: new theory of function updates
  1006     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1007   may also be iterated as in f(a:=b,c:=d,...);
  1008 
  1009 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1010 
  1011 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1012   [previously, this check worked only if the rewrite rule was unconditional]
  1013   Now rew can involve either definitions or equalities (either == or =).
  1014 
  1015 * case_tac provided for compatibility with HOL
  1016     (like the old excluded_middle_tac, but with subgoals swapped)
  1017 
  1018 
  1019 *** Internal programming interfaces ***
  1020 
  1021 * Pure: several new basic modules made available for general use, see
  1022 also src/Pure/README;
  1023 
  1024 * improved the theory data mechanism to support encapsulation (data
  1025 kind name replaced by private Object.kind, acting as authorization
  1026 key); new type-safe user interface via functor TheoryDataFun; generic
  1027 print_data function becomes basically useless;
  1028 
  1029 * removed global_names compatibility flag -- all theory declarations
  1030 are qualified by default;
  1031 
  1032 * module Pure/Syntax now offers quote / antiquote translation
  1033 functions (useful for Hoare logic etc. with implicit dependencies);
  1034 see HOL/ex/Antiquote for an example use;
  1035 
  1036 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1037 cterm -> thm;
  1038 
  1039 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1040 subgoal;
  1041 
  1042 * Display.print_goals function moved to Locale.print_goals;
  1043 
  1044 * standard print function for goals supports current_goals_markers
  1045 variable for marking begin of proof, end of proof, start of goal; the
  1046 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1047 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1048 for example;
  1049 
  1050 
  1051 
  1052 New in Isabelle98 (January 1998)
  1053 --------------------------------
  1054 
  1055 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1056 
  1057 * changed lexical syntax of terms / types: dots made part of long
  1058 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1059 
  1060 * simpset (and claset) reference variable replaced by functions
  1061 simpset / simpset_ref;
  1062 
  1063 * no longer supports theory aliases (via merge) and non-trivial
  1064 implicit merge of thms' signatures;
  1065 
  1066 * most internal names of constants changed due to qualified names;
  1067 
  1068 * changed Pure/Sequence interface (see Pure/seq.ML);
  1069 
  1070 
  1071 *** General Changes ***
  1072 
  1073 * hierachically structured name spaces (for consts, types, axms, thms
  1074 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1075 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1076 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1077 long_names for fully qualified output names; NOTE: ML programs
  1078 (special tactics, packages etc.) referring to internal names may have
  1079 to be adapted to cope with fully qualified names; in case of severe
  1080 backward campatibility problems try setting 'global_names' at compile
  1081 time to have enrything declared within a flat name space; one may also
  1082 fine tune name declarations in theories via the 'global' and 'local'
  1083 section;
  1084 
  1085 * reimplemented the implicit simpset and claset using the new anytype
  1086 data filed in signatures; references simpset:simpset ref etc. are
  1087 replaced by functions simpset:unit->simpset and
  1088 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1089 to patch your ML files accordingly;
  1090 
  1091 * HTML output now includes theory graph data for display with Java
  1092 applet or isatool browser; data generated automatically via isatool
  1093 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1094 
  1095 * defs may now be conditional; improved rewrite_goals_tac to handle
  1096 conditional equations;
  1097 
  1098 * defs now admits additional type arguments, using TYPE('a) syntax;
  1099 
  1100 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1101 creates a new theory node; implicit merge of thms' signatures is
  1102 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1103 transfer:theory->thm->thm in (rare) cases;
  1104 
  1105 * improved handling of draft signatures / theories; draft thms (and
  1106 ctyps, cterms) are automatically promoted to real ones;
  1107 
  1108 * slightly changed interfaces for oracles: admit many per theory, named
  1109 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1110 
  1111 * print_goals: optional output of const types (set show_consts and
  1112 show_types);
  1113 
  1114 * improved output of warnings (###) and errors (***);
  1115 
  1116 * subgoal_tac displays a warning if the new subgoal has type variables;
  1117 
  1118 * removed old README and Makefiles;
  1119 
  1120 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1121 
  1122 * removed obsolete init_pps and init_database;
  1123 
  1124 * deleted the obsolete tactical STATE, which was declared by
  1125     fun STATE tacfun st = tacfun st st;
  1126 
  1127 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1128 (which abbreviates $HOME);
  1129 
  1130 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1131 use isatool fixseq to adapt your ML programs (this works for fully
  1132 qualified references to the Sequence structure only!);
  1133 
  1134 * use_thy no longer requires writable current directory; it always
  1135 reloads .ML *and* .thy file, if either one is out of date;
  1136 
  1137 
  1138 *** Classical Reasoner ***
  1139 
  1140 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1141 tactics that use classical reasoning to simplify a subgoal without
  1142 splitting it into several subgoals;
  1143 
  1144 * Safe_tac: like safe_tac but uses the default claset;
  1145 
  1146 
  1147 *** Simplifier ***
  1148 
  1149 * added simplification meta rules:
  1150     (asm_)(full_)simplify: simpset -> thm -> thm;
  1151 
  1152 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1153 logics (again);
  1154 
  1155 * added prems argument to simplification procedures;
  1156 
  1157 * HOL, FOL, ZF: added infix function `addsplits':
  1158   instead of `<simpset> setloop (split_tac <thms>)'
  1159   you can simply write `<simpset> addsplits <thms>'
  1160 
  1161 
  1162 *** Syntax ***
  1163 
  1164 * TYPE('a) syntax for type reflection terms;
  1165 
  1166 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1167 
  1168 * pretty printer: changed order of mixfix annotation preference (again!);
  1169 
  1170 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1171 
  1172 
  1173 *** HOL ***
  1174 
  1175 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1176   with `addloop' of the simplifier to faciliate case splitting in premises.
  1177 
  1178 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1179 
  1180 * HOL/Auth: new protocol proofs including some for the Internet
  1181   protocol TLS;
  1182 
  1183 * HOL/Map: new theory of `maps' a la VDM;
  1184 
  1185 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1186 cancelling out common nat summands from =, <, <= (in)equalities, or
  1187 differences; simplification procedures nat_cancel_factor for
  1188 cancelling common factor from =, <, <= (in)equalities over natural
  1189 sums; nat_cancel contains both kinds of procedures, it is installed by
  1190 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1191 
  1192 * HOL/simplifier: terms of the form
  1193   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1194   are rewritten to
  1195   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1196   and those of the form
  1197   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1198   are rewritten to
  1199   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1200 
  1201 * HOL/datatype
  1202   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1203 
  1204   P(t_case f1 ... fn x) =
  1205      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1206         ...
  1207        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1208      )
  1209 
  1210   and a theorem `split_t_case_asm' of the form
  1211 
  1212   P(t_case f1 ... fn x) =
  1213     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1214         ...
  1215        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1216      )
  1217   which can be added to a simpset via `addsplits'. The existing theorems
  1218   expand_list_case and expand_option_case have been renamed to
  1219   split_list_case and split_option_case.
  1220 
  1221 * HOL/Arithmetic:
  1222   - `pred n' is automatically converted to `n-1'.
  1223     Users are strongly encouraged not to use `pred' any longer,
  1224     because it will disappear altogether at some point.
  1225   - Users are strongly encouraged to write "0 < n" rather than
  1226     "n ~= 0". Theorems and proof tools have been modified towards this
  1227     `standard'.
  1228 
  1229 * HOL/Lists:
  1230   the function "set_of_list" has been renamed "set" (and its theorems too);
  1231   the function "nth" now takes its arguments in the reverse order and
  1232   has acquired the infix notation "!" as in "xs!n".
  1233 
  1234 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1235 
  1236 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1237   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1238 
  1239 * HOL/record: extensible records with schematic structural subtyping
  1240 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1241 still lacks various theorems and concrete record syntax;
  1242 
  1243 
  1244 *** HOLCF ***
  1245 
  1246 * removed "axioms" and "generated by" sections;
  1247 
  1248 * replaced "ops" section by extended "consts" section, which is capable of
  1249   handling the continuous function space "->" directly;
  1250 
  1251 * domain package:
  1252   . proves theorems immediately and stores them in the theory,
  1253   . creates hierachical name space,
  1254   . now uses normal mixfix annotations (instead of cinfix...),
  1255   . minor changes to some names and values (for consistency),
  1256   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1257   . separator between mutual domain defs: changed "," to "and",
  1258   . improved handling of sort constraints;  now they have to
  1259     appear on the left-hand side of the equations only;
  1260 
  1261 * fixed LAM <x,y,zs>.b syntax;
  1262 
  1263 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1264 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1265 
  1266 
  1267 *** FOL and ZF ***
  1268 
  1269 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1270   with `addloop' of the simplifier to faciliate case splitting in premises.
  1271 
  1272 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1273 in HOL, they strip ALL and --> from proved theorems;
  1274 
  1275 
  1276 
  1277 New in Isabelle94-8 (May 1997)
  1278 ------------------------------
  1279 
  1280 *** General Changes ***
  1281 
  1282 * new utilities to build / run / maintain Isabelle etc. (in parts
  1283 still somewhat experimental); old Makefiles etc. still functional;
  1284 
  1285 * new 'Isabelle System Manual';
  1286 
  1287 * INSTALL text, together with ./configure and ./build scripts;
  1288 
  1289 * reimplemented type inference for greater efficiency, better error
  1290 messages and clean internal interface;
  1291 
  1292 * prlim command for dealing with lots of subgoals (an easier way of
  1293 setting goals_limit);
  1294 
  1295 
  1296 *** Syntax ***
  1297 
  1298 * supports alternative (named) syntax tables (parser and pretty
  1299 printer); internal interface is provided by add_modesyntax(_i);
  1300 
  1301 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1302 be used in conjunction with the Isabelle symbol font; uses the
  1303 "symbols" syntax table;
  1304 
  1305 * added token_translation interface (may translate name tokens in
  1306 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1307 the current print_mode); IMPORTANT: user print translation functions
  1308 are responsible for marking newly introduced bounds
  1309 (Syntax.mark_boundT);
  1310 
  1311 * token translations for modes "xterm" and "xterm_color" that display
  1312 names in bold, underline etc. or colors (which requires a color
  1313 version of xterm);
  1314 
  1315 * infixes may now be declared with names independent of their syntax;
  1316 
  1317 * added typed_print_translation (like print_translation, but may
  1318 access type of constant);
  1319 
  1320 
  1321 *** Classical Reasoner ***
  1322 
  1323 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1324 some limitations.  Blast_tac...
  1325   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1326   + ignores elimination rules that don't have the correct format
  1327         (the conclusion MUST be a formula variable)
  1328   + ignores types, which can make HOL proofs fail
  1329   + rules must not require higher-order unification, e.g. apply_type in ZF
  1330     [message "Function Var's argument not a bound variable" relates to this]
  1331   + its proof strategy is more general but can actually be slower
  1332 
  1333 * substitution with equality assumptions no longer permutes other
  1334 assumptions;
  1335 
  1336 * minor changes in semantics of addafter (now called addaltern); renamed
  1337 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1338 (and access functions for it);
  1339 
  1340 * improved combination of classical reasoner and simplifier:
  1341   + functions for handling clasimpsets
  1342   + improvement of addss: now the simplifier is called _after_ the
  1343     safe steps.
  1344   + safe variant of addss called addSss: uses safe simplifications
  1345     _during_ the safe steps. It is more complete as it allows multiple
  1346     instantiations of unknowns (e.g. with slow_tac).
  1347 
  1348 *** Simplifier ***
  1349 
  1350 * added interface for simplification procedures (functions that
  1351 produce *proven* rewrite rules on the fly, depending on current
  1352 redex);
  1353 
  1354 * ordering on terms as parameter (used for ordered rewriting);
  1355 
  1356 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1357 
  1358 * the solver is now split into a safe and an unsafe part.
  1359 This should be invisible for the normal user, except that the
  1360 functions setsolver and addsolver have been renamed to setSolver and
  1361 addSolver; added safe_asm_full_simp_tac;
  1362 
  1363 
  1364 *** HOL ***
  1365 
  1366 * a generic induction tactic `induct_tac' which works for all datatypes and
  1367 also for type `nat';
  1368 
  1369 * a generic case distinction tactic `exhaust_tac' which works for all
  1370 datatypes and also for type `nat';
  1371 
  1372 * each datatype comes with a function `size';
  1373 
  1374 * patterns in case expressions allow tuple patterns as arguments to
  1375 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1376 
  1377 * primrec now also works with type nat;
  1378 
  1379 * recdef: a new declaration form, allows general recursive functions to be
  1380 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1381 
  1382 * the constant for negation has been renamed from "not" to "Not" to
  1383 harmonize with FOL, ZF, LK, etc.;
  1384 
  1385 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1386 infinite lists;
  1387 
  1388 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1389 
  1390 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1391 problems in commutative rings, using axiomatic type classes for + and *;
  1392 
  1393 * more examples in HOL/MiniML and HOL/Auth;
  1394 
  1395 * more default rewrite rules for quantifiers, union/intersection;
  1396 
  1397 * a new constant `arbitrary == @x.False';
  1398 
  1399 * HOLCF/IOA replaces old HOL/IOA;
  1400 
  1401 * HOLCF changes: derived all rules and arities
  1402   + axiomatic type classes instead of classes
  1403   + typedef instead of faking type definitions
  1404   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1405   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1406   + eliminated the types void, one, tr
  1407   + use unit lift and bool lift (with translations) instead of one and tr
  1408   + eliminated blift from Lift3.thy (use Def instead of blift)
  1409   all eliminated rules are derived as theorems --> no visible changes ;
  1410 
  1411 
  1412 *** ZF ***
  1413 
  1414 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1415 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1416 as ZF_cs addSIs [equalityI];
  1417 
  1418 
  1419 
  1420 New in Isabelle94-7 (November 96)
  1421 ---------------------------------
  1422 
  1423 * allowing negative levels (as offsets) in prlev and choplev;
  1424 
  1425 * super-linear speedup for large simplifications;
  1426 
  1427 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1428 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1429 FAIL); can suppress it using the command Delsimps (ex_simps @
  1430 all_simps); De Morgan laws are also now included, by default;
  1431 
  1432 * improved printing of ==>  :  ~:
  1433 
  1434 * new object-logic "Sequents" adds linear logic, while replacing LK
  1435 and Modal (thanks to Sara Kalvala);
  1436 
  1437 * HOL/Auth: correctness proofs for authentication protocols;
  1438 
  1439 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1440 examples on HOL/Auth);
  1441 
  1442 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1443 the rewriter and classical reasoner simultaneously;
  1444 
  1445 * function uresult no longer returns theorems in "standard" format;
  1446 regain previous version by: val uresult = standard o uresult;
  1447 
  1448 
  1449 
  1450 New in Isabelle94-6
  1451 -------------------
  1452 
  1453 * oracles -- these establish an interface between Isabelle and trusted
  1454 external reasoners, which may deliver results as theorems;
  1455 
  1456 * proof objects (in particular record all uses of oracles);
  1457 
  1458 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1459 
  1460 * "constdefs" section in theory files;
  1461 
  1462 * "primrec" section (HOL) no longer requires names;
  1463 
  1464 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1465 
  1466 
  1467 
  1468 New in Isabelle94-5
  1469 -------------------
  1470 
  1471 * reduced space requirements;
  1472 
  1473 * automatic HTML generation from theories;
  1474 
  1475 * theory files no longer require "..." (quotes) around most types;
  1476 
  1477 * new examples, including two proofs of the Church-Rosser theorem;
  1478 
  1479 * non-curried (1994) version of HOL is no longer distributed;
  1480 
  1481 
  1482 
  1483 New in Isabelle94-4
  1484 -------------------
  1485 
  1486 * greatly reduced space requirements;
  1487 
  1488 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1489 
  1490 * searchable theorem database (see the section "Retrieving theorems" on
  1491 page 8 of the Reference Manual);
  1492 
  1493 * new examples, including Grabczewski's monumental case study of the
  1494 Axiom of Choice;
  1495 
  1496 * The previous version of HOL renamed to Old_HOL;
  1497 
  1498 * The new version of HOL (previously called CHOL) uses a curried syntax
  1499 for functions.  Application looks like f a b instead of f(a,b);
  1500 
  1501 * Mutually recursive inductive definitions finally work in HOL;
  1502 
  1503 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1504 translates to the operator "split";
  1505 
  1506 
  1507 
  1508 New in Isabelle94-3
  1509 -------------------
  1510 
  1511 * new infix operator, addss, allowing the classical reasoner to
  1512 perform simplification at each step of its search.  Example:
  1513         fast_tac (cs addss ss)
  1514 
  1515 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1516 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1517 look like (a,b) instead of <a,b>;
  1518 
  1519 * PLEASE NOTE: CHOL will eventually replace HOL!
  1520 
  1521 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1522 It translates to the operator "split".  A new theory of integers is available;
  1523 
  1524 * In ZF, integer numerals now denote two's-complement binary integers.
  1525 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1526 
  1527 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1528 of the Axiom of Choice;
  1529 
  1530 
  1531 
  1532 New in Isabelle94-2
  1533 -------------------
  1534 
  1535 * Significantly faster resolution;
  1536 
  1537 * the different sections in a .thy file can now be mixed and repeated
  1538 freely;
  1539 
  1540 * Database of theorems for FOL, HOL and ZF.  New
  1541 commands including qed, qed_goal and bind_thm store theorems in the database.
  1542 
  1543 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1544 a given theory (thms_of), or find out what theory a theorem was proved in
  1545 (theory_of_thm);
  1546 
  1547 * Bugs fixed in the inductive definition and datatype packages;
  1548 
  1549 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1550 and HOL_dup_cs obsolete;
  1551 
  1552 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1553 have been removed;
  1554 
  1555 * Simpler definition of function space in ZF;
  1556 
  1557 * new results about cardinal and ordinal arithmetic in ZF;
  1558 
  1559 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1560 types;
  1561 
  1562 
  1563 $Id$