NEWS
author wenzelm
Tue Sep 12 22:13:23 2000 +0200 (2000-09-12)
changeset 9941 fe05af7ec816
parent 9937 431c96ac997e
child 9971 e0164f01d55a
permissions -rw-r--r--
renamed atts: rulify to rule_format, elimify to elim_format;
     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    26 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;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; renamed
    56 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
    57 should have to change intro!! to intro? only); replaced "delrule" by
    58 "rule del";
    59 
    60 * Isar: changed syntax of local blocks from {{ }} to { };
    61 
    62 * Isar: renamed 'RS' attribute to 'THEN';
    63 
    64 * Isar: renamed some attributes (rulify -> rule_format, elimify -> elim_format, ...);
    65 
    66 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
    67 
    68 * Provers: strengthened force_tac by using new first_best_tac;
    69 
    70 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
    71   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
    72 use instead the strong form,
    73   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
    74 In HOL, FOL and ZF the function cla_make_elim will create such rules
    75 from destruct-rules;
    76 
    77 * Provers: safe_asm_full_simp_tac is no longer in the simplifier signature. Use
    78   val safe_asm_full_simp_tac = generic_simp_tac true (true,true,true);
    79   if required.
    80 
    81 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
    82 timing flag supersedes proof_timing and Toplevel.trace;
    83 
    84 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    85 
    86 * ML: PureThy.add_defs gets additional argument to indicate potential
    87 overloading (usually false);
    88 
    89 * LaTeX: several changes of isabelle.sty;
    90 
    91 
    92 *** Document preparation ***
    93 
    94 * formal comments (text blocks etc.) in new-style theories may now
    95 contain antiquotations of thm/prop/term/typ/text to be presented
    96 according to latex print mode; concrete syntax is like this:
    97 @{term[show_types] "f(x) = a + x"};
    98 
    99 * isatool mkdir provides easy setup of Isabelle session directories,
   100 including proper document sources;
   101 
   102 * generated LaTeX sources are now deleted after successful run
   103 (isatool document -c); may retain a copy somewhere else via -D option
   104 of isatool usedir;
   105 
   106 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   107 style files, achieving self-contained LaTeX sources;
   108 
   109 * old-style theories now produce (crude) LaTeX output as well;
   110 
   111 * browser info session directories are now self-contained (may be put
   112 on WWW server seperately); improved graphs of nested sessions; removed
   113 graph for 'all sessions';
   114 
   115 * several improvements in isabelle.sty; \isabellestyle{it} produces
   116 near math mode output; \isamarkupheader is now \section by default;
   117 
   118 
   119 *** Isar ***
   120 
   121 * Pure: local results and corresponding term bindings are now subject
   122 to Hindley-Milner polymorphism (similar to ML); this accommodates
   123 incremental type-inference nicely;
   124 
   125 * Pure: new derived language element 'obtain' supports generalized
   126 existence reasoning;
   127 
   128 * Pure: new calculational elements 'moreover' and 'ultimately' support
   129 accumulation of results, without applying any rules yet;
   130 
   131 * Pure: scalable support for case-analysis type proofs: new 'case'
   132 language element refers to local contexts symbolically, as produced by
   133 certain proof methods; internally, case names are attached to theorems
   134 as "tags";
   135 
   136 * Pure: theory command 'hide' removes declarations from
   137 class/type/const name spaces;
   138 
   139 * Pure: theory command 'defs' supports option "(overloaded)" to
   140 indicate potential overloading;
   141 
   142 * Pure: changed syntax of local blocks from {{ }} to { };
   143 
   144 * Pure: renamed 'RS' attribute to 'THEN';
   145 
   146 * Pure: syntax of sorts made 'inner', i.e. have to write "{a, b, c}"
   147 instead of {a, b, c};
   148 
   149 * Pure now provides its own version of intro/elim/dest attributes;
   150 useful for building new logics, but beware of confusion with the
   151 version in Provers/classical;
   152 
   153 * Pure: the local context of (non-atomic) goals is provided via case
   154 name 'antecedent';
   155 
   156 * Pure: removed obsolete 'transfer' attribute (transfer of thms to the
   157 current context is now done automatically);
   158 
   159 * Pure: theory command 'method_setup' provides a simple interface for
   160 definining proof methods in ML;
   161 
   162 * Provers: 'simp' method now supports 'cong' modifiers;
   163 
   164 * Provers: hypsubst support; also plain subst and symmetric attribute
   165 (the latter supercedes [RS sym]);
   166 
   167 * Provers: splitter support (via 'split' attribute and 'simp' method
   168 modifier); 'simp' method: 'only:' modifier removes loopers as well
   169 (including splits);
   170 
   171 * Provers: added 'fastsimp' and 'clarsimp' methods (combination of
   172 Simplifier and Classical reasoner);
   173 
   174 * Provers: added 'arith_split' attribute;
   175 
   176 * HOL: new proof method 'cases' and improved version of 'induct' now
   177 support named cases; major packages (inductive, datatype, primrec,
   178 recdef) support case names and properly name parameters;
   179 
   180 * HOL: removed 'case_split' thm binding, should use 'cases' proof
   181 method anyway;
   182 
   183 * HOL: removed obsolete expand_if = split_if; theorems if_splits =
   184 split_if split_if_asm; datatype package provides theorems foo.splits =
   185 foo.split foo.split_asm for each datatype;
   186 
   187 * HOL/Calculation: new rules for substitution in inequalities
   188 (monotonicity conditions are extracted to be proven at end);
   189 
   190 * HOL/inductive: rename "intrs" to "intros" (potential
   191 INCOMPATIBILITY); emulation of mk_cases feature for proof scripts:
   192 'inductive_cases' command and 'ind_cases' method; NOTE: use (cases
   193 (simplified)) method in proper proofs;
   194 
   195 * Provers: intro/elim/dest attributes changed; renamed
   196 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   197 most cases, one should have to change intro!! to intro? only);
   198 replaced "delrule" by "rule del";
   199 
   200 * names of theorems etc. may be natural numbers as well;
   201 
   202 * 'pr' command: optional arguments for goals_limit and
   203 ProofContext.prems_limit; no longer prints theory contexts, but only
   204 proof states;
   205 
   206 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   207 additional print modes to be specified; e.g. "pr(latex)" will print
   208 proof state according to the Isabelle LaTeX style;
   209 
   210 * improved support for emulating tactic scripts, including proof
   211 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   212 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   213 (for HOL datatypes);
   214 
   215 * simplified (more robust) goal selection of proof methods: 1st goal,
   216 all goals, or explicit goal specifier (tactic emulation); thus 'proof
   217 method scripts' have to be in depth-first order;
   218 
   219 * tuned 'let' syntax: replaced 'as' keyword by 'and';
   220 
   221 * removed 'help' command, which hasn't been too helpful anyway; should
   222 instead use individual commands for printing items (print_commands,
   223 print_methods etc.);
   224 
   225 * added 'nothing' --- the empty list of theorems;
   226 
   227 
   228 *** HOL ***
   229 
   230 * HOL/Lambda: converted into new-style theory and document;
   231 
   232 * HOL/Algebra: new theory of rings and univariate polynomials, by
   233 Clemens Ballarin;
   234 
   235 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
   236 Arithmetic, by Thomas M Rasmussen;
   237 
   238 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
   239 basically a generalized version of de-Bruijn representation; very
   240 useful in avoiding lifting of operations;
   241 
   242 * HOL/NumberTheory: Chinese Remainder Theorem, Fermat/Euler Theorem, Wilson's
   243 Theorem, by Thomas M Rasmussen;
   244 
   245 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog;
   246 
   247 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   248 
   249 * HOL/record: added general record equality rule to simpset; fixed
   250 select-update simplification procedure to handle extended records as
   251 well; admit "r" as field name;
   252 
   253 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   254 other numeric types and also as the identity of groups, rings, etc.;
   255 
   256 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   257 Types nat and int belong to this axclass;
   258 
   259 * greatly improved simplification involving numerals of type nat, int, real:
   260    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   261    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   262   two terms #m*u and #n*u are replaced by #(m+n)*u
   263     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   264   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   265     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   266 
   267 * HOL: meson_tac is available (previously in ex/meson.ML).  It is a powerful
   268    prover for predicate logic but knows nothing of clasets.  For examples of
   269    what it can do, see ex/mesontest.ML and ex/mesontest2.ML;
   270 
   271 * HOL: new version of "case_tac" subsumes both boolean case split and
   272 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   273 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   274 
   275 * HOL: simplification no longer dives into case-expressions: only the
   276 selector expression is simplified, but not the remaining arms. To
   277 enable full simplification of case-expressions for datatype t, you
   278 need to remove t.weak_case_cong from the simpset, either permanently
   279 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   280 
   281 * HOL/recdef: the recursion equations generated by 'recdef' for
   282 function 'f' are now called f.simps instead of f.rules; if all
   283 termination conditions are proved automatically, these simplification
   284 rules are added to the simpset, as in primrec; rules may be named
   285 individually as well, resulting in a separate list of theorems for
   286 each equation;
   287 
   288 * HOL/While is a new theory that provides a while-combinator. It
   289 permits the definition of tail-recursive functions without the
   290 provision of a termination measure. The latter is necessary once the
   291 invariant proof rule for while is applied.
   292 
   293 * HOL: new (overloaded) notation for the set of elements below/above some
   294 element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   295 
   296 * HOL: theorems impI, allI, ballI bound as "strip";
   297 
   298 * new tactic induct_thm_tac: thm -> string -> int -> tactic
   299 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   300 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   301 
   302 * new functions rulify/rulify_no_asm: thm -> thm for turning outer
   303 -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   304 
   305 * theory Sexp now in HOL/Induct examples (it used to be part of main
   306 HOL, but was unused);
   307 
   308 * fewer consts declared as global (e.g. have to refer to "Lfp.lfp"
   309 instead of "lfp" internally; affects ML packages only);
   310 
   311 * tuned AST representation of nested pairs, avoiding bogus output in
   312 case of overlap with user translations (e.g. judgements over tuples);
   313 
   314 
   315 *** ZF ***
   316 
   317 * simplification automatically cancels common terms in arithmetic expressions
   318 over nat and int;
   319 
   320 * new treatment of nat to minimize type-checking: all operators coerce their 
   321 operands to a natural number using the function natify, making the algebraic
   322 laws unconditional;
   323 
   324 * as above, for int: operators coerce their operands to an integer using the
   325 function intify;
   326 
   327 * the integer library now contains many of the usual laws for the orderings, 
   328 including $<=, and monotonicity laws for $+ and $*; 
   329 
   330 * new example ZF/ex/NatSum to demonstrate integer arithmetic simplification;
   331 
   332 *** FOL & ZF ***
   333 
   334 * AddIffs now available, giving theorems of the form P<->Q to the
   335 simplifier and classical reasoner simultaneously;
   336 
   337 
   338 *** General ***
   339 
   340 * Provers: delrules now handles destruct rules as well (no longer need
   341 explicit make_elim);
   342 
   343 * Provers: blast(_tac) now handles actual object-logic rules as
   344 assumptions; note that auto(_tac) uses blast(_tac) internally as well;
   345 
   346 * Provers: Simplifier.easy_setup provides a fast path to basic
   347 Simplifier setup for new object-logics;
   348 
   349 * Pure: AST translation rules no longer require constant head on LHS;
   350 
   351 * Pure: improved name spaces: ambiguous output is qualified; support
   352 for hiding of names;
   353 
   354 * system: compression of ML heaps images may now be controlled via -c
   355 option of isabelle and isatool usedir (currently only observed by
   356 Poly/ML);
   357 
   358 * system: provide TAGS file for Isabelle sources;
   359 
   360 * settings: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   361 XSYMBOL_HOME; no longer need to do manual configuration in most
   362 situations;
   363 
   364 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   365 order;
   366 
   367 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   368 timing flag supersedes proof_timing and Toplevel.trace;
   369 
   370 * ML: PureThy.add_defs gets additional argument to indicate potential
   371 overloading (usually false);
   372 
   373 * ML: new combinators |>> and |>>> for incremental transformations
   374 with secondary results (e.g. certain theory extensions):
   375 
   376 
   377 
   378 New in Isabelle99 (October 1999)
   379 --------------------------------
   380 
   381 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   382 
   383 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   384 are no longer simplified.  (This allows the simplifier to unfold recursive
   385 functional programs.)  To restore the old behaviour, declare
   386 
   387     Delcongs [if_weak_cong];
   388 
   389 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   390 complement;
   391 
   392 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   393 
   394 * HOL/datatype: mutual_induct_tac no longer exists --
   395   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   396 
   397 * HOL/typedef: fixed type inference for representing set; type
   398 arguments now have to occur explicitly on the rhs as type constraints;
   399 
   400 * ZF: The con_defs part of an inductive definition may no longer refer
   401 to constants declared in the same theory;
   402 
   403 * HOL, ZF: the function mk_cases, generated by the inductive
   404 definition package, has lost an argument.  To simplify its result, it
   405 uses the default simpset instead of a supplied list of theorems.
   406 
   407 * HOL/List: the constructors of type list are now Nil and Cons;
   408 
   409 * Simplifier: the type of the infix ML functions
   410         setSSolver addSSolver setSolver addSolver
   411 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   412 for packaging solvers. A solver is created via
   413         mk_solver: string -> (thm list -> int -> tactic) -> solver
   414 where the string argument is only a comment.
   415 
   416 
   417 *** Proof tools ***
   418 
   419 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   420 decision procedure for linear arithmetic. Currently it is used for
   421 types `nat', `int', and `real' in HOL (see below); it can, should and
   422 will be instantiated for other types and logics as well.
   423 
   424 * The simplifier now accepts rewrite rules with flexible heads, eg
   425      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   426   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   427   matching.
   428 
   429 
   430 *** General ***
   431 
   432 * New Isabelle/Isar subsystem provides an alternative to traditional
   433 tactical theorem proving; together with the ProofGeneral/isar user
   434 interface it offers an interactive environment for developing human
   435 readable proof documents (Isar == Intelligible semi-automated
   436 reasoning); for further information see isatool doc isar-ref,
   437 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   438 
   439 * improved and simplified presentation of theories: better HTML markup
   440 (including colors), graph views in several sizes; isatool usedir now
   441 provides a proper interface for user theories (via -P option); actual
   442 document preparation based on (PDF)LaTeX is available as well (for
   443 new-style theories only); see isatool doc system for more information;
   444 
   445 * native support for Proof General, both for classic Isabelle and
   446 Isabelle/Isar;
   447 
   448 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   449 using the graph browser tool;
   450 
   451 * Isabelle manuals now also available as PDF;
   452 
   453 * theory loader rewritten from scratch (may not be fully
   454 bug-compatible); old loadpath variable has been replaced by show_path,
   455 add_path, del_path, reset_path functions; new operations such as
   456 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   457 isatool doc ref);
   458 
   459 * improved isatool install: option -k creates KDE application icon,
   460 option -p DIR installs standalone binaries;
   461 
   462 * added ML_PLATFORM setting (useful for cross-platform installations);
   463 more robust handling of platform specific ML images for SML/NJ;
   464 
   465 * the settings environment is now statically scoped, i.e. it is never
   466 created again in sub-processes invoked from isabelle, isatool, or
   467 Isabelle;
   468 
   469 * path element specification '~~' refers to '$ISABELLE_HOME';
   470 
   471 * in locales, the "assumes" and "defines" parts may be omitted if
   472 empty;
   473 
   474 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   475 long arrows);
   476 
   477 * new print_mode "HTML";
   478 
   479 * new flag show_tags controls display of tags of theorems (which are
   480 basically just comments that may be attached by some tools);
   481 
   482 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   483 mode and goal output format:
   484 
   485 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   486 244c244
   487 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   488 ---
   489 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   490 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   491 181c181
   492 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   493 ---
   494 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   495 
   496 * function bind_thms stores lists of theorems (cf. bind_thm);
   497 
   498 * new shorthand tactics ftac, eatac, datac, fatac;
   499 
   500 * qed (and friends) now accept "" as result name; in that case the
   501 theorem is not stored, but proper checks and presentation of the
   502 result still apply;
   503 
   504 * theorem database now also indexes constants "Trueprop", "all",
   505 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   506 
   507 
   508 *** HOL ***
   509 
   510 ** HOL arithmetic **
   511 
   512 * There are now decision procedures for linear arithmetic over nat and
   513 int:
   514 
   515 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   516 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   517 are treated as atomic; subformulae not involving type `nat' or `int'
   518 are ignored; quantified subformulae are ignored unless they are
   519 positive universal or negative existential. The tactic has to be
   520 invoked by hand and can be a little bit slow. In particular, the
   521 running time is exponential in the number of occurrences of `min' and
   522 `max', and `-' on `nat'.
   523 
   524 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   525 (negated) (in)equalities among the premises and the conclusion into
   526 account (i.e. no compound formulae) and does not know about `min' and
   527 `max', and `-' on `nat'. It is fast and is used automatically by the
   528 simplifier.
   529 
   530 NB: At the moment, these decision procedures do not cope with mixed
   531 nat/int formulae where the two parts interact, such as `m < n ==>
   532 int(m) < int(n)'.
   533 
   534 * HOL/Numeral provides a generic theory of numerals (encoded
   535 efficiently as bit strings); setup for types nat/int/real is in place;
   536 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   537 int, existing theories and proof scripts may require a few additional
   538 type constraints;
   539 
   540 * integer division and remainder can now be performed on constant
   541 arguments;
   542 
   543 * many properties of integer multiplication, division and remainder
   544 are now available;
   545 
   546 * An interface to the Stanford Validity Checker (SVC) is available through the
   547 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   548 are proved automatically.  SVC must be installed separately, and its results
   549 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   550 invocation of the underlying oracle).  For SVC see
   551   http://verify.stanford.edu/SVC
   552 
   553 * IsaMakefile: the HOL-Real target now builds an actual image;
   554 
   555 
   556 ** HOL misc **
   557 
   558 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   559 (in Isabelle/Isar) -- by Gertrud Bauer;
   560 
   561 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   562 analysis for assembly languages with subtypes;
   563 
   564 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   565 -- avoids syntactic ambiguities and treats state, transition, and
   566 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   567 changed syntax and (many) tactics;
   568 
   569 * HOL/inductive: Now also handles more general introduction rules such
   570   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   571   theorems are now maintained within the theory (maintained via the
   572   "mono" attribute);
   573 
   574 * HOL/datatype: Now also handles arbitrarily branching datatypes
   575   (using function types) such as
   576 
   577   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   578 
   579 * HOL/record: record_simproc (part of the default simpset) takes care
   580 of selectors applied to updated records; record_split_tac is no longer
   581 part of the default claset; update_defs may now be removed from the
   582 simpset in many cases; COMPATIBILITY: old behavior achieved by
   583 
   584   claset_ref () := claset() addSWrapper record_split_wrapper;
   585   Delsimprocs [record_simproc]
   586 
   587 * HOL/typedef: fixed type inference for representing set; type
   588 arguments now have to occur explicitly on the rhs as type constraints;
   589 
   590 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   591 names rather than an ML expression;
   592 
   593 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   594 supplied later.  Program schemes can be defined, such as
   595     "While B C s = (if B s then While B C (C s) else s)"
   596 where the well-founded relation can be chosen after B and C have been given.
   597 
   598 * HOL/List: the constructors of type list are now Nil and Cons;
   599 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   600 course, ML tools referring to List.list.op # etc. have to be adapted;
   601 
   602 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   603 disabled by default; run isabelle with option -m HOL to get back to
   604 the original Gordon/HOL-style output;
   605 
   606 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   607 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   608 
   609 * HOL basic syntax simplified (more orthogonal): all variants of
   610 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   611 Eps operator is provided as well: "SOME x. P[x]";
   612 
   613 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   614 
   615 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   616 thus available for user theories;
   617 
   618 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   619 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   620 time;
   621 
   622 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   623 several times and then mp;
   624 
   625 
   626 *** LK ***
   627 
   628 * the notation <<...>> is now available as a notation for sequences of
   629 formulas;
   630 
   631 * the simplifier is now installed
   632 
   633 * the axiom system has been generalized (thanks to Soren Heilmann)
   634 
   635 * the classical reasoner now has a default rule database
   636 
   637 
   638 *** ZF ***
   639 
   640 * new primrec section allows primitive recursive functions to be given
   641 directly (as in HOL) over datatypes and the natural numbers;
   642 
   643 * new tactics induct_tac and exhaust_tac for induction (or case
   644 analysis) over datatypes and the natural numbers;
   645 
   646 * the datatype declaration of type T now defines the recursor T_rec;
   647 
   648 * simplification automatically does freeness reasoning for datatype
   649 constructors;
   650 
   651 * automatic type-inference, with AddTCs command to insert new
   652 type-checking rules;
   653 
   654 * datatype introduction rules are now added as Safe Introduction rules
   655 to the claset;
   656 
   657 * the syntax "if P then x else y" is now available in addition to
   658 if(P,x,y);
   659 
   660 
   661 *** Internal programming interfaces ***
   662 
   663 * tuned simplifier trace output; new flag debug_simp;
   664 
   665 * structures Vartab / Termtab (instances of TableFun) offer efficient
   666 tables indexed by indexname_ord / term_ord (compatible with aconv);
   667 
   668 * AxClass.axclass_tac lost the theory argument;
   669 
   670 * tuned current_goals_markers semantics: begin / end goal avoids
   671 printing empty lines;
   672 
   673 * removed prs and prs_fn hook, which was broken because it did not
   674 include \n in its semantics, forcing writeln to add one
   675 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   676 string -> unit if you really want to output text without newline;
   677 
   678 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   679 plain output, interface builders may have to enable 'isabelle_font'
   680 mode to get Isabelle font glyphs as before;
   681 
   682 * refined token_translation interface; INCOMPATIBILITY: output length
   683 now of type real instead of int;
   684 
   685 * theory loader actions may be traced via new ThyInfo.add_hook
   686 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   687 your own database of information attached to *whole* theories -- as
   688 opposed to intra-theory data slots offered via TheoryDataFun;
   689 
   690 * proper handling of dangling sort hypotheses (at last!);
   691 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   692 extra sort hypotheses that can be witnessed from the type signature;
   693 the force_strip_shyps flag is gone, any remaining shyps are simply
   694 left in the theorem (with a warning issued by strip_shyps_warning);
   695 
   696 
   697 
   698 New in Isabelle98-1 (October 1998)
   699 ----------------------------------
   700 
   701 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   702 
   703 * several changes of automated proof tools;
   704 
   705 * HOL: major changes to the inductive and datatype packages, including
   706 some minor incompatibilities of theory syntax;
   707 
   708 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   709 called `inj_on';
   710 
   711 * HOL: removed duplicate thms in Arith:
   712   less_imp_add_less  should be replaced by  trans_less_add1
   713   le_imp_add_le      should be replaced by  trans_le_add1
   714 
   715 * HOL: unary minus is now overloaded (new type constraints may be
   716 required);
   717 
   718 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   719 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   720 now taken as an integer constant.
   721 
   722 * Pure: ML function 'theory_of' renamed to 'theory';
   723 
   724 
   725 *** Proof tools ***
   726 
   727 * Simplifier:
   728   1. Asm_full_simp_tac is now more aggressive.
   729      1. It will sometimes reorient premises if that increases their power to
   730         simplify.
   731      2. It does no longer proceed strictly from left to right but may also
   732         rotate premises to achieve further simplification.
   733      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   734      old Asm_full_simp_tac in that it does not rotate premises.
   735   2. The simplifier now knows a little bit about nat-arithmetic.
   736 
   737 * Classical reasoner: wrapper mechanism for the classical reasoner now
   738 allows for selected deletion of wrappers, by introduction of names for
   739 wrapper functionals.  This implies that addbefore, addSbefore,
   740 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   741 and that adding two tactics with the same name overwrites the first
   742 one (emitting a warning).
   743   type wrapper = (int -> tactic) -> (int -> tactic)
   744   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   745   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   746   delWrapper, delSWrapper: claset *  string            -> claset
   747   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   748 
   749 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   750 semantics; addbefore now affects only the unsafe part of step_tac
   751 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   752 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   753 by Force_tac;
   754 
   755 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   756 compWrapper; added safe wrapper (and access functions for it);
   757 
   758 * HOL/split_all_tac is now much faster and fails if there is nothing
   759 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   760 and the names of the automatically generated variables have changed.
   761 split_all_tac has moved within claset() from unsafe wrappers to safe
   762 wrappers, which means that !!-bound variables are split much more
   763 aggressively, and safe_tac and clarify_tac now split such variables.
   764 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   765 Note: the same holds for record_split_tac, which does the job of
   766 split_all_tac for record fields.
   767 
   768 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   769 permanently to the default simpset using Addsplits just like
   770 Addsimps. They can be removed via Delsplits just like
   771 Delsimps. Lower-case versions are also available.
   772 
   773 * HOL/Simplifier: The rule split_if is now part of the default
   774 simpset. This means that the simplifier will eliminate all occurrences
   775 of if-then-else in the conclusion of a goal. To prevent this, you can
   776 either remove split_if completely from the default simpset by
   777 `Delsplits [split_if]' or remove it in a specific call of the
   778 simplifier using `... delsplits [split_if]'.  You can also add/delete
   779 other case splitting rules to/from the default simpset: every datatype
   780 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   781 t is the name of the datatype).
   782 
   783 * Classical reasoner / Simplifier combination: new force_tac (and
   784 derivatives Force_tac, force) combines rewriting and classical
   785 reasoning (and whatever other tools) similarly to auto_tac, but is
   786 aimed to solve the given subgoal completely.
   787 
   788 
   789 *** General ***
   790 
   791 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   792 and `goalw': the theory is no longer needed as an explicit argument -
   793 the current theory context is used; assumptions are no longer returned
   794 at the ML-level unless one of them starts with ==> or !!; it is
   795 recommended to convert to these new commands using isatool fixgoal
   796 (backup your sources first!);
   797 
   798 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   799 the current theory context, and 'theory' to lookup stored theories;
   800 
   801 * new theory section 'locale' for declaring constants, assumptions and
   802 definitions that have local scope;
   803 
   804 * new theory section 'nonterminals' for purely syntactic types;
   805 
   806 * new theory section 'setup' for generic ML setup functions
   807 (e.g. package initialization);
   808 
   809 * the distribution now includes Isabelle icons: see
   810 lib/logo/isabelle-{small,tiny}.xpm;
   811 
   812 * isatool install - install binaries with absolute references to
   813 ISABELLE_HOME/bin;
   814 
   815 * isatool logo -- create instances of the Isabelle logo (as EPS);
   816 
   817 * print mode 'emacs' reserved for Isamode;
   818 
   819 * support multiple print (ast) translations per constant name;
   820 
   821 * theorems involving oracles are now printed with a suffixed [!];
   822 
   823 
   824 *** HOL ***
   825 
   826 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   827 
   828 * HOL/inductive package reorganized and improved: now supports mutual
   829 definitions such as
   830 
   831   inductive EVEN ODD
   832     intrs
   833       null "0 : EVEN"
   834       oddI "n : EVEN ==> Suc n : ODD"
   835       evenI "n : ODD ==> Suc n : EVEN"
   836 
   837 new theorem list "elims" contains an elimination rule for each of the
   838 recursive sets; inductive definitions now handle disjunctive premises
   839 correctly (also ZF);
   840 
   841 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   842 "mutual_induct" no longer exists - the induction rule is always
   843 contained in "induct";
   844 
   845 
   846 * HOL/datatype package re-implemented and greatly improved: now
   847 supports mutually recursive datatypes such as
   848 
   849   datatype
   850     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   851             | SUM ('a aexp) ('a aexp)
   852             | DIFF ('a aexp) ('a aexp)
   853             | NUM 'a
   854   and
   855     'a bexp = LESS ('a aexp) ('a aexp)
   856             | AND ('a bexp) ('a bexp)
   857             | OR ('a bexp) ('a bexp)
   858 
   859 as well as indirectly recursive datatypes such as
   860 
   861   datatype
   862     ('a, 'b) term = Var 'a
   863                   | App 'b ((('a, 'b) term) list)
   864 
   865 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   866 induction on mutually / indirectly recursive datatypes.
   867 
   868 Primrec equations are now stored in theory and can be accessed via
   869 <function_name>.simps.
   870 
   871 INCOMPATIBILITIES:
   872 
   873   - Theories using datatypes must now have theory Datatype as an
   874     ancestor.
   875   - The specific <typename>.induct_tac no longer exists - use the
   876     generic induct_tac instead.
   877   - natE has been renamed to nat.exhaust - use exhaust_tac
   878     instead of res_inst_tac ... natE. Note that the variable
   879     names in nat.exhaust differ from the names in natE, this
   880     may cause some "fragile" proofs to fail.
   881   - The theorems split_<typename>_case and split_<typename>_case_asm
   882     have been renamed to <typename>.split and <typename>.split_asm.
   883   - Since default sorts of type variables are now handled correctly,
   884     some datatype definitions may have to be annotated with explicit
   885     sort constraints.
   886   - Primrec definitions no longer require function name and type
   887     of recursive argument.
   888 
   889 Consider using isatool fixdatatype to adapt your theories and proof
   890 scripts to the new package (backup your sources first!).
   891 
   892 
   893 * HOL/record package: considerably improved implementation; now
   894 includes concrete syntax for record types, terms, updates; theorems
   895 for surjective pairing and splitting !!-bound record variables; proof
   896 support is as follows:
   897 
   898   1) standard conversions (selectors or updates applied to record
   899 constructor terms) are part of the standard simpset;
   900 
   901   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   902 made part of standard simpset and claset via addIffs;
   903 
   904   3) a tactic for record field splitting (record_split_tac) is part of
   905 the standard claset (addSWrapper);
   906 
   907 To get a better idea about these rules you may retrieve them via
   908 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   909 the name of your record type.
   910 
   911 The split tactic 3) conceptually simplifies by the following rule:
   912 
   913   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   914 
   915 Thus any record variable that is bound by meta-all will automatically
   916 blow up into some record constructor term, consequently the
   917 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   918 solve record problems automatically.
   919 
   920 
   921 * reorganized the main HOL image: HOL/Integ and String loaded by
   922 default; theory Main includes everything;
   923 
   924 * automatic simplification of integer sums and comparisons, using cancellation;
   925 
   926 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   927 
   928 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   929 
   930 * many new identities for unions, intersections, set difference, etc.;
   931 
   932 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   933 called split_if, split_split, split_sum_case and split_nat_case (to go
   934 with add/delsplits);
   935 
   936 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   937 (?x::unit) = (); this is made part of the default simpset, which COULD
   938 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   939 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   940 unit_abs_eta_conv is added in order to counter the effect of
   941 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   942 %u.f();
   943 
   944 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   945 makes more sense);
   946 
   947 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   948   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   949   disjointness reasoning but breaking a few old proofs.
   950 
   951 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   952 to 'converse' from 'inverse' (for compatibility with ZF and some
   953 literature);
   954 
   955 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   956 the well-founded relation;
   957 
   958 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   959     Compl A.  The "Compl" syntax remains available as input syntax for this
   960     release ONLY.
   961 
   962 * HOL/Update: new theory of function updates:
   963     f(a:=b) == %x. if x=a then b else f x
   964 may also be iterated as in f(a:=b,c:=d,...);
   965 
   966 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   967 
   968 * HOL/List:
   969   - new function list_update written xs[i:=v] that updates the i-th
   970     list position. May also be iterated as in xs[i:=a,j:=b,...].
   971   - new function `upt' written [i..j(] which generates the list
   972     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   973     bound write [i..j], which is a shorthand for [i..j+1(].
   974   - new lexicographic orderings and corresponding wellfoundedness theorems.
   975 
   976 * HOL/Arith:
   977   - removed 'pred' (predecessor) function;
   978   - generalized some theorems about n-1;
   979   - many new laws about "div" and "mod";
   980   - new laws about greatest common divisors (see theory ex/Primes);
   981 
   982 * HOL/Relation: renamed the relational operator r^-1 "converse"
   983 instead of "inverse";
   984 
   985 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   986   of the multiset ordering;
   987 
   988 * directory HOL/Real: a construction of the reals using Dedekind cuts
   989   (not included by default);
   990 
   991 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   992 
   993 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   994   programs, i.e. different program variables may have different types.
   995 
   996 * calling (stac rew i) now fails if "rew" has no effect on the goal
   997   [previously, this check worked only if the rewrite rule was unconditional]
   998   Now rew can involve either definitions or equalities (either == or =).
   999 
  1000 
  1001 *** ZF ***
  1002 
  1003 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1004   only the theorems proved on ZF.ML;
  1005 
  1006 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1007   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1008   disjointness reasoning but breaking a few old proofs.
  1009 
  1010 * ZF/Update: new theory of function updates
  1011     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1012   may also be iterated as in f(a:=b,c:=d,...);
  1013 
  1014 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1015 
  1016 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1017   [previously, this check worked only if the rewrite rule was unconditional]
  1018   Now rew can involve either definitions or equalities (either == or =).
  1019 
  1020 * case_tac provided for compatibility with HOL
  1021     (like the old excluded_middle_tac, but with subgoals swapped)
  1022 
  1023 
  1024 *** Internal programming interfaces ***
  1025 
  1026 * Pure: several new basic modules made available for general use, see
  1027 also src/Pure/README;
  1028 
  1029 * improved the theory data mechanism to support encapsulation (data
  1030 kind name replaced by private Object.kind, acting as authorization
  1031 key); new type-safe user interface via functor TheoryDataFun; generic
  1032 print_data function becomes basically useless;
  1033 
  1034 * removed global_names compatibility flag -- all theory declarations
  1035 are qualified by default;
  1036 
  1037 * module Pure/Syntax now offers quote / antiquote translation
  1038 functions (useful for Hoare logic etc. with implicit dependencies);
  1039 see HOL/ex/Antiquote for an example use;
  1040 
  1041 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1042 cterm -> thm;
  1043 
  1044 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1045 subgoal;
  1046 
  1047 * Display.print_goals function moved to Locale.print_goals;
  1048 
  1049 * standard print function for goals supports current_goals_markers
  1050 variable for marking begin of proof, end of proof, start of goal; the
  1051 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1052 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1053 for example;
  1054 
  1055 
  1056 
  1057 New in Isabelle98 (January 1998)
  1058 --------------------------------
  1059 
  1060 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1061 
  1062 * changed lexical syntax of terms / types: dots made part of long
  1063 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1064 
  1065 * simpset (and claset) reference variable replaced by functions
  1066 simpset / simpset_ref;
  1067 
  1068 * no longer supports theory aliases (via merge) and non-trivial
  1069 implicit merge of thms' signatures;
  1070 
  1071 * most internal names of constants changed due to qualified names;
  1072 
  1073 * changed Pure/Sequence interface (see Pure/seq.ML);
  1074 
  1075 
  1076 *** General Changes ***
  1077 
  1078 * hierachically structured name spaces (for consts, types, axms, thms
  1079 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1080 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1081 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1082 long_names for fully qualified output names; NOTE: ML programs
  1083 (special tactics, packages etc.) referring to internal names may have
  1084 to be adapted to cope with fully qualified names; in case of severe
  1085 backward campatibility problems try setting 'global_names' at compile
  1086 time to have enrything declared within a flat name space; one may also
  1087 fine tune name declarations in theories via the 'global' and 'local'
  1088 section;
  1089 
  1090 * reimplemented the implicit simpset and claset using the new anytype
  1091 data filed in signatures; references simpset:simpset ref etc. are
  1092 replaced by functions simpset:unit->simpset and
  1093 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1094 to patch your ML files accordingly;
  1095 
  1096 * HTML output now includes theory graph data for display with Java
  1097 applet or isatool browser; data generated automatically via isatool
  1098 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1099 
  1100 * defs may now be conditional; improved rewrite_goals_tac to handle
  1101 conditional equations;
  1102 
  1103 * defs now admits additional type arguments, using TYPE('a) syntax;
  1104 
  1105 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1106 creates a new theory node; implicit merge of thms' signatures is
  1107 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1108 transfer:theory->thm->thm in (rare) cases;
  1109 
  1110 * improved handling of draft signatures / theories; draft thms (and
  1111 ctyps, cterms) are automatically promoted to real ones;
  1112 
  1113 * slightly changed interfaces for oracles: admit many per theory, named
  1114 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1115 
  1116 * print_goals: optional output of const types (set show_consts and
  1117 show_types);
  1118 
  1119 * improved output of warnings (###) and errors (***);
  1120 
  1121 * subgoal_tac displays a warning if the new subgoal has type variables;
  1122 
  1123 * removed old README and Makefiles;
  1124 
  1125 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1126 
  1127 * removed obsolete init_pps and init_database;
  1128 
  1129 * deleted the obsolete tactical STATE, which was declared by
  1130     fun STATE tacfun st = tacfun st st;
  1131 
  1132 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1133 (which abbreviates $HOME);
  1134 
  1135 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1136 use isatool fixseq to adapt your ML programs (this works for fully
  1137 qualified references to the Sequence structure only!);
  1138 
  1139 * use_thy no longer requires writable current directory; it always
  1140 reloads .ML *and* .thy file, if either one is out of date;
  1141 
  1142 
  1143 *** Classical Reasoner ***
  1144 
  1145 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1146 tactics that use classical reasoning to simplify a subgoal without
  1147 splitting it into several subgoals;
  1148 
  1149 * Safe_tac: like safe_tac but uses the default claset;
  1150 
  1151 
  1152 *** Simplifier ***
  1153 
  1154 * added simplification meta rules:
  1155     (asm_)(full_)simplify: simpset -> thm -> thm;
  1156 
  1157 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1158 logics (again);
  1159 
  1160 * added prems argument to simplification procedures;
  1161 
  1162 * HOL, FOL, ZF: added infix function `addsplits':
  1163   instead of `<simpset> setloop (split_tac <thms>)'
  1164   you can simply write `<simpset> addsplits <thms>'
  1165 
  1166 
  1167 *** Syntax ***
  1168 
  1169 * TYPE('a) syntax for type reflection terms;
  1170 
  1171 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1172 
  1173 * pretty printer: changed order of mixfix annotation preference (again!);
  1174 
  1175 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1176 
  1177 
  1178 *** HOL ***
  1179 
  1180 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1181   with `addloop' of the simplifier to faciliate case splitting in premises.
  1182 
  1183 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1184 
  1185 * HOL/Auth: new protocol proofs including some for the Internet
  1186   protocol TLS;
  1187 
  1188 * HOL/Map: new theory of `maps' a la VDM;
  1189 
  1190 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1191 cancelling out common nat summands from =, <, <= (in)equalities, or
  1192 differences; simplification procedures nat_cancel_factor for
  1193 cancelling common factor from =, <, <= (in)equalities over natural
  1194 sums; nat_cancel contains both kinds of procedures, it is installed by
  1195 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1196 
  1197 * HOL/simplifier: terms of the form
  1198   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1199   are rewritten to
  1200   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1201   and those of the form
  1202   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1203   are rewritten to
  1204   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1205 
  1206 * HOL/datatype
  1207   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1208 
  1209   P(t_case f1 ... fn x) =
  1210      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1211         ...
  1212        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1213      )
  1214 
  1215   and a theorem `split_t_case_asm' of the form
  1216 
  1217   P(t_case f1 ... fn x) =
  1218     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1219         ...
  1220        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1221      )
  1222   which can be added to a simpset via `addsplits'. The existing theorems
  1223   expand_list_case and expand_option_case have been renamed to
  1224   split_list_case and split_option_case.
  1225 
  1226 * HOL/Arithmetic:
  1227   - `pred n' is automatically converted to `n-1'.
  1228     Users are strongly encouraged not to use `pred' any longer,
  1229     because it will disappear altogether at some point.
  1230   - Users are strongly encouraged to write "0 < n" rather than
  1231     "n ~= 0". Theorems and proof tools have been modified towards this
  1232     `standard'.
  1233 
  1234 * HOL/Lists:
  1235   the function "set_of_list" has been renamed "set" (and its theorems too);
  1236   the function "nth" now takes its arguments in the reverse order and
  1237   has acquired the infix notation "!" as in "xs!n".
  1238 
  1239 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1240 
  1241 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1242   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1243 
  1244 * HOL/record: extensible records with schematic structural subtyping
  1245 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1246 still lacks various theorems and concrete record syntax;
  1247 
  1248 
  1249 *** HOLCF ***
  1250 
  1251 * removed "axioms" and "generated by" sections;
  1252 
  1253 * replaced "ops" section by extended "consts" section, which is capable of
  1254   handling the continuous function space "->" directly;
  1255 
  1256 * domain package:
  1257   . proves theorems immediately and stores them in the theory,
  1258   . creates hierachical name space,
  1259   . now uses normal mixfix annotations (instead of cinfix...),
  1260   . minor changes to some names and values (for consistency),
  1261   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1262   . separator between mutual domain defs: changed "," to "and",
  1263   . improved handling of sort constraints;  now they have to
  1264     appear on the left-hand side of the equations only;
  1265 
  1266 * fixed LAM <x,y,zs>.b syntax;
  1267 
  1268 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1269 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1270 
  1271 
  1272 *** FOL and ZF ***
  1273 
  1274 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1275   with `addloop' of the simplifier to faciliate case splitting in premises.
  1276 
  1277 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1278 in HOL, they strip ALL and --> from proved theorems;
  1279 
  1280 
  1281 
  1282 New in Isabelle94-8 (May 1997)
  1283 ------------------------------
  1284 
  1285 *** General Changes ***
  1286 
  1287 * new utilities to build / run / maintain Isabelle etc. (in parts
  1288 still somewhat experimental); old Makefiles etc. still functional;
  1289 
  1290 * new 'Isabelle System Manual';
  1291 
  1292 * INSTALL text, together with ./configure and ./build scripts;
  1293 
  1294 * reimplemented type inference for greater efficiency, better error
  1295 messages and clean internal interface;
  1296 
  1297 * prlim command for dealing with lots of subgoals (an easier way of
  1298 setting goals_limit);
  1299 
  1300 
  1301 *** Syntax ***
  1302 
  1303 * supports alternative (named) syntax tables (parser and pretty
  1304 printer); internal interface is provided by add_modesyntax(_i);
  1305 
  1306 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1307 be used in conjunction with the Isabelle symbol font; uses the
  1308 "symbols" syntax table;
  1309 
  1310 * added token_translation interface (may translate name tokens in
  1311 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1312 the current print_mode); IMPORTANT: user print translation functions
  1313 are responsible for marking newly introduced bounds
  1314 (Syntax.mark_boundT);
  1315 
  1316 * token translations for modes "xterm" and "xterm_color" that display
  1317 names in bold, underline etc. or colors (which requires a color
  1318 version of xterm);
  1319 
  1320 * infixes may now be declared with names independent of their syntax;
  1321 
  1322 * added typed_print_translation (like print_translation, but may
  1323 access type of constant);
  1324 
  1325 
  1326 *** Classical Reasoner ***
  1327 
  1328 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1329 some limitations.  Blast_tac...
  1330   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1331   + ignores elimination rules that don't have the correct format
  1332         (the conclusion MUST be a formula variable)
  1333   + ignores types, which can make HOL proofs fail
  1334   + rules must not require higher-order unification, e.g. apply_type in ZF
  1335     [message "Function Var's argument not a bound variable" relates to this]
  1336   + its proof strategy is more general but can actually be slower
  1337 
  1338 * substitution with equality assumptions no longer permutes other
  1339 assumptions;
  1340 
  1341 * minor changes in semantics of addafter (now called addaltern); renamed
  1342 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1343 (and access functions for it);
  1344 
  1345 * improved combination of classical reasoner and simplifier:
  1346   + functions for handling clasimpsets
  1347   + improvement of addss: now the simplifier is called _after_ the
  1348     safe steps.
  1349   + safe variant of addss called addSss: uses safe simplifications
  1350     _during_ the safe steps. It is more complete as it allows multiple
  1351     instantiations of unknowns (e.g. with slow_tac).
  1352 
  1353 *** Simplifier ***
  1354 
  1355 * added interface for simplification procedures (functions that
  1356 produce *proven* rewrite rules on the fly, depending on current
  1357 redex);
  1358 
  1359 * ordering on terms as parameter (used for ordered rewriting);
  1360 
  1361 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1362 
  1363 * the solver is now split into a safe and an unsafe part.
  1364 This should be invisible for the normal user, except that the
  1365 functions setsolver and addsolver have been renamed to setSolver and
  1366 addSolver; added safe_asm_full_simp_tac;
  1367 
  1368 
  1369 *** HOL ***
  1370 
  1371 * a generic induction tactic `induct_tac' which works for all datatypes and
  1372 also for type `nat';
  1373 
  1374 * a generic case distinction tactic `exhaust_tac' which works for all
  1375 datatypes and also for type `nat';
  1376 
  1377 * each datatype comes with a function `size';
  1378 
  1379 * patterns in case expressions allow tuple patterns as arguments to
  1380 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1381 
  1382 * primrec now also works with type nat;
  1383 
  1384 * recdef: a new declaration form, allows general recursive functions to be
  1385 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1386 
  1387 * the constant for negation has been renamed from "not" to "Not" to
  1388 harmonize with FOL, ZF, LK, etc.;
  1389 
  1390 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1391 infinite lists;
  1392 
  1393 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1394 
  1395 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1396 problems in commutative rings, using axiomatic type classes for + and *;
  1397 
  1398 * more examples in HOL/MiniML and HOL/Auth;
  1399 
  1400 * more default rewrite rules for quantifiers, union/intersection;
  1401 
  1402 * a new constant `arbitrary == @x.False';
  1403 
  1404 * HOLCF/IOA replaces old HOL/IOA;
  1405 
  1406 * HOLCF changes: derived all rules and arities
  1407   + axiomatic type classes instead of classes
  1408   + typedef instead of faking type definitions
  1409   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1410   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1411   + eliminated the types void, one, tr
  1412   + use unit lift and bool lift (with translations) instead of one and tr
  1413   + eliminated blift from Lift3.thy (use Def instead of blift)
  1414   all eliminated rules are derived as theorems --> no visible changes ;
  1415 
  1416 
  1417 *** ZF ***
  1418 
  1419 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1420 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1421 as ZF_cs addSIs [equalityI];
  1422 
  1423 
  1424 
  1425 New in Isabelle94-7 (November 96)
  1426 ---------------------------------
  1427 
  1428 * allowing negative levels (as offsets) in prlev and choplev;
  1429 
  1430 * super-linear speedup for large simplifications;
  1431 
  1432 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1433 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1434 FAIL); can suppress it using the command Delsimps (ex_simps @
  1435 all_simps); De Morgan laws are also now included, by default;
  1436 
  1437 * improved printing of ==>  :  ~:
  1438 
  1439 * new object-logic "Sequents" adds linear logic, while replacing LK
  1440 and Modal (thanks to Sara Kalvala);
  1441 
  1442 * HOL/Auth: correctness proofs for authentication protocols;
  1443 
  1444 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1445 examples on HOL/Auth);
  1446 
  1447 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1448 the rewriter and classical reasoner simultaneously;
  1449 
  1450 * function uresult no longer returns theorems in "standard" format;
  1451 regain previous version by: val uresult = standard o uresult;
  1452 
  1453 
  1454 
  1455 New in Isabelle94-6
  1456 -------------------
  1457 
  1458 * oracles -- these establish an interface between Isabelle and trusted
  1459 external reasoners, which may deliver results as theorems;
  1460 
  1461 * proof objects (in particular record all uses of oracles);
  1462 
  1463 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1464 
  1465 * "constdefs" section in theory files;
  1466 
  1467 * "primrec" section (HOL) no longer requires names;
  1468 
  1469 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1470 
  1471 
  1472 
  1473 New in Isabelle94-5
  1474 -------------------
  1475 
  1476 * reduced space requirements;
  1477 
  1478 * automatic HTML generation from theories;
  1479 
  1480 * theory files no longer require "..." (quotes) around most types;
  1481 
  1482 * new examples, including two proofs of the Church-Rosser theorem;
  1483 
  1484 * non-curried (1994) version of HOL is no longer distributed;
  1485 
  1486 
  1487 
  1488 New in Isabelle94-4
  1489 -------------------
  1490 
  1491 * greatly reduced space requirements;
  1492 
  1493 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1494 
  1495 * searchable theorem database (see the section "Retrieving theorems" on
  1496 page 8 of the Reference Manual);
  1497 
  1498 * new examples, including Grabczewski's monumental case study of the
  1499 Axiom of Choice;
  1500 
  1501 * The previous version of HOL renamed to Old_HOL;
  1502 
  1503 * The new version of HOL (previously called CHOL) uses a curried syntax
  1504 for functions.  Application looks like f a b instead of f(a,b);
  1505 
  1506 * Mutually recursive inductive definitions finally work in HOL;
  1507 
  1508 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1509 translates to the operator "split";
  1510 
  1511 
  1512 
  1513 New in Isabelle94-3
  1514 -------------------
  1515 
  1516 * new infix operator, addss, allowing the classical reasoner to
  1517 perform simplification at each step of its search.  Example:
  1518         fast_tac (cs addss ss)
  1519 
  1520 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1521 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1522 look like (a,b) instead of <a,b>;
  1523 
  1524 * PLEASE NOTE: CHOL will eventually replace HOL!
  1525 
  1526 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1527 It translates to the operator "split".  A new theory of integers is available;
  1528 
  1529 * In ZF, integer numerals now denote two's-complement binary integers.
  1530 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1531 
  1532 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1533 of the Axiom of Choice;
  1534 
  1535 
  1536 
  1537 New in Isabelle94-2
  1538 -------------------
  1539 
  1540 * Significantly faster resolution;
  1541 
  1542 * the different sections in a .thy file can now be mixed and repeated
  1543 freely;
  1544 
  1545 * Database of theorems for FOL, HOL and ZF.  New
  1546 commands including qed, qed_goal and bind_thm store theorems in the database.
  1547 
  1548 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1549 a given theory (thms_of), or find out what theory a theorem was proved in
  1550 (theory_of_thm);
  1551 
  1552 * Bugs fixed in the inductive definition and datatype packages;
  1553 
  1554 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1555 and HOL_dup_cs obsolete;
  1556 
  1557 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1558 have been removed;
  1559 
  1560 * Simpler definition of function space in ZF;
  1561 
  1562 * new results about cardinal and ordinal arithmetic in ZF;
  1563 
  1564 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1565 types;
  1566 
  1567 
  1568 $Id$