NEWS
author wenzelm
Thu Aug 17 10:29:23 2000 +0200 (2000-08-17)
changeset 9612 e6ba17cd012e
parent 9577 9e66e8ed8237
child 9647 e9623f47275b
permissions -rw-r--r--
Isar/Pure: renamed 'RS' attribute to 'THEN';
Isar/Provers: added 'arith_split' attribute;
Isar/Provers: added 'fastsimp' and 'clarsimp' methods;
Isar/HOL/inductive: rename "intrs" to "intros";
HOL/record: added general record equality rule to simpset;
     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    26 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;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/Real: "rabs" replaced by overloaded "abs" function;
    41 
    42 * HOL/ML: even fewer consts are declared as global (see theories Ord,
    43 Lfp, Gfp, WF); this only affects ML packages that refer to const names
    44 internally;
    45 
    46 * HOL, ZF: syntax for quotienting wrt an equivalence relation changed from
    47   A/r to A//r;
    48 
    49 * ZF: new treatment of arithmetic (nat & int) may break some old proofs;
    50 
    51 * Isar/Provers: intro/elim/dest attributes: changed
    52 intro/intro!/intro!!  flags to intro!/intro/intro? (in most cases, one
    53 should have to change intro!! to intro? only);
    54 
    55 * Isar: changed syntax of local blocks from {{ }} to { };
    56 
    57 * Isar: renamed 'RS' attribute to 'THEN';
    58 
    59 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
    60 
    61 * Provers: strengthened force_tac by using new first_best_tac;
    62 
    63 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
    64   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
    65 use instead the strong form,
    66   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
    67 In HOL, FOL and ZF the function cla_make_elim will create such rules
    68 from destruct-rules;
    69 
    70 * Provers: safe_asm_full_simp_tac is no longer in the simplifier signature. Use
    71   val safe_asm_full_simp_tac = generic_simp_tac true (true,true,true);
    72   if required.
    73 
    74 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
    75 timing flag supersedes proof_timing and Toplevel.trace;
    76 
    77 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    78 
    79 * ML: PureThy.add_defs gets additional argument to indicate potential
    80 overloading (usually false);
    81 
    82 * LaTeX: several changes of isabelle.sty;
    83 
    84 
    85 *** Document preparation ***
    86 
    87 * formal comments (text blocks etc.) in new-style theories may now
    88 contain antiquotations of thm/prop/term/typ to be presented according
    89 to latex print mode; concrete syntax is like this: @{term[show_types]
    90 "f(x) = a + x"};
    91 
    92 * isatool mkdir provides easy setup of Isabelle session directories,
    93 including proper document sources;
    94 
    95 * generated LaTeX sources are now deleted after successful run
    96 (isatool document -c); may retain a copy somewhere else via -D option
    97 of isatool usedir;
    98 
    99 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   100 style files, achieving self-contained LaTeX sources;
   101 
   102 * old-style theories now produce (crude) LaTeX output as well;
   103 
   104 * browser info session directories are now self-contained (may be put
   105 on WWW server seperately); improved graphs of nested sessions; removed
   106 graph for 'all sessions';
   107 
   108 * several improvements in isabelle.sty; \isamarkupheader is now
   109 \section by default;
   110 
   111 
   112 *** Isar ***
   113 
   114 * Pure: local results and corresponding term bindings are now subject
   115 to Hindley-Milner polymorphism (similar to ML); this accommodates
   116 incremental type-inference nicely;
   117 
   118 * Pure: new derived language element 'obtain' supports generalized
   119 existence reasoning;
   120 
   121 * Pure: new calculational elements 'moreover' and 'ultimately' support
   122 accumulation of results, without applying any rules yet;
   123 
   124 * Pure: scalable support for case-analysis type proofs: new 'case'
   125 language element refers to local contexts symbolically, as produced by
   126 certain proof methods; internally, case names are attached to theorems
   127 as "tags";
   128 
   129 * Pure: theory command 'hide' removes declarations from
   130 class/type/const name spaces;
   131 
   132 * Pure: theory command 'defs' supports option "(overloaded)" to
   133 indicate potential overloading;
   134 
   135 * Pure: changed syntax of local blocks from {{ }} to { };
   136 
   137 * Pure: renamed 'RS' attribute to 'THEN';
   138 
   139 * Pure: syntax of sorts made 'inner', i.e. have to write "{a, b, c}"
   140 instead of {a, b, c};
   141 
   142 * Pure now provides its own version of intro/elim/dest attributes;
   143 useful for building new logics, but beware of confusion with the
   144 version in Provers/classical;
   145 
   146 * Pure: the local context of (non-atomic) goals is provided via case
   147 name 'antecedent';
   148 
   149 * Pure: removed obsolete 'transfer' attribute (transfer of thms to the
   150 current context is now done automatically);
   151 
   152 * Pure: theory command 'method_setup' provides a simple interface for
   153 definining proof methods in ML;
   154 
   155 * Provers: hypsubst support; also plain subst and symmetric attribute
   156 (the latter supercedes [RS sym]);
   157 
   158 * Provers: splitter support (via 'split' attribute and 'simp' method
   159 modifier); 'simp' method: 'only:' modifier removes loopers as well
   160 (including splits);
   161 
   162 * Provers: added 'fastsimp' and 'clarsimp' methods (combination of
   163 Simplifier and Classical reasoner);
   164 
   165 * Provers: added 'arith_split' attribute;
   166 
   167 * HOL: new proof method 'cases' and improved version of 'induct' now
   168 support named cases; major packages (inductive, datatype, primrec,
   169 recdef) support case names and properly name parameters;
   170 
   171 * HOL: removed 'case_split' thm binding, should use 'cases' proof
   172 method anyway;
   173 
   174 * HOL: removed obsolete expand_if = split_if; theorems if_splits =
   175 split_if split_if_asm; datatype package provides theorems foo.splits =
   176 foo.split foo.split_asm for each datatype;
   177 
   178 * HOL/Calculation: new rules for substitution in inequalities
   179 (monotonicity conditions are extracted to be proven at end);
   180 
   181 * HOL/inductive: rename "intrs" to "intros" (potential
   182 INCOMPATIBILITY); emulation of mk_cases feature for proof scripts:
   183 'inductive_cases' command and 'ind_cases' method; NOTE: use (cases
   184 (simplified)) method in proper proofs;
   185 
   186 * Provers: intro/elim/dest attributes: changed intro/intro!/intro!!
   187 flags to intro!/intro/intro? (in most cases, one should have to change
   188 intro!! to intro? only);
   189 
   190 * names of theorems etc. may be natural numbers as well;
   191 
   192 * 'pr' command: optional goals_limit argument; no longer prints theory
   193 contexts, but only proof states;
   194 
   195 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   196 additional print modes to be specified; e.g. "pr(latex)" will print
   197 proof state according to the Isabelle LaTeX style;
   198 
   199 * improved support for emulating tactic scripts, including proof
   200 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   201 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   202 (for HOL datatypes);
   203 
   204 * simplified (more robust) goal selection of proof methods: 1st goal,
   205 all goals, or explicit goal specifier (tactic emulation); thus 'proof
   206 method scripts' have to be in depth-first order;
   207 
   208 * tuned 'let' syntax: replaced 'as' keyword by 'and';
   209 
   210 * removed 'help' command, which hasn't been too helpful anyway; should
   211 instead use individual commands for printing items (print_commands,
   212 print_methods etc.);
   213 
   214 * added 'nothing' --- the empty list of theorems;
   215 
   216 
   217 *** HOL ***
   218 
   219 * HOL/Algebra: new theory of rings and univariate polynomials, by
   220 Clemens Ballarin;
   221 
   222 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
   223 Arithmetic, by Thomas M Rasmussen;
   224 
   225 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
   226 basically a generalized version of de-Bruijn representation; very
   227 useful in avoiding lifting of operations;
   228 
   229 * HOL/NumberTheory: Chinese Remainder Theorem, Fermat/Euler Theorem, Wilson's
   230 Theorem, by Thomas M Rasmussen;
   231 
   232 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog;
   233 
   234 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   235 
   236 * HOL/record: added general record equality rule to simpset; fixed
   237 select-update simplification procedure to handle extended records as
   238 well; admit "r" as field name;
   239 
   240 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   241 other numeric types and also as the identity of groups, rings, etc.;
   242 
   243 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   244 Types nat and int belong to this axclass;
   245 
   246 * greatly improved simplification involving numerals of type nat, int, real:
   247    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   248    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   249   two terms #m*u and #n*u are replaced by #(m+n)*u
   250     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   251   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   252     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   253 
   254 * HOL: new version of "case_tac" subsumes both boolean case split and
   255 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   256 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   257 
   258 * HOL: simplification no longer dives into case-expressions: only the
   259 selector expression is simplified, but not the remaining arms. To
   260 enable full simplification of case-expressions for datatype t, you
   261 need to remove t.weak_case_cong from the simpset, either permanently
   262 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   263 
   264 * HOL/recdef: the recursion equations generated by 'recdef' for
   265 function 'f' are now called f.simps instead of f.rules; if all
   266 termination conditions are proved automatically, these simplification
   267 rules are added to the simpset, as in primrec; rules may be named
   268 individually as well, resulting in a separate list of theorems for
   269 each equation;
   270 
   271 * HOL/While is a new theory that provides a while-combinator. It
   272 permits the definition of tail-recursive functions without the
   273 provision of a termination measure. The latter is necessary once the
   274 invariant proof rule for while is applied.
   275 
   276 * HOL: new (overloaded) notation for the set of elements below/above some
   277 element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   278 
   279 * HOL: theorems impI, allI, ballI bound as "strip";
   280 
   281 * theory Sexp now in HOL/Induct examples (it used to be part of main
   282 HOL, but was unused);
   283 
   284 * fewer consts declared as global (e.g. have to refer to "Lfp.lfp"
   285 instead of "lfp" internally; affects ML packages only);
   286 
   287 * tuned AST representation of nested pairs, avoiding bogus output in
   288 case of overlap with user translations (e.g. judgements over tuples);
   289 
   290 
   291 *** ZF ***
   292 
   293 * simplification automatically cancels common terms in arithmetic expressions
   294 over nat and int;
   295 
   296 * new treatment of nat to minimize type-checking: all operators coerce their 
   297 operands to a natural number using the function natify, making the algebraic
   298 laws unconditional;
   299 
   300 * as above, for int: operators coerce their operands to an integer using the
   301 function intify;
   302 
   303 * the integer library now contains many of the usual laws for the orderings, 
   304 including $<=, and monotonicity laws for $+ and $*; 
   305 
   306 
   307 *** FOL & ZF ***
   308 
   309 * AddIffs now available, giving theorems of the form P<->Q to the
   310 simplifier and classical reasoner simultaneously;
   311 
   312 
   313 *** General ***
   314 
   315 * blast(_tac) now handles actual object-logic rules as assumptions;
   316 note that auto(_tac) uses blast(_tac) internally, too;
   317 
   318 * AST translation rules no longer require constant head on LHS;
   319 
   320 * improved name spaces: ambiguous output is qualified; support for
   321 hiding of names;
   322 
   323 * compression of ML heaps images may now be controlled via -c option
   324 of isabelle and isatool usedir (currently only observed by Poly/ML);
   325 
   326 * provide TAGS file for Isabelle sources;
   327 
   328 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   329 order;
   330 
   331 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   332 timing flag supersedes proof_timing and Toplevel.trace;
   333 
   334 * ML: PureThy.add_defs gets additional argument to indicate potential
   335 overloading (usually false);
   336 
   337 * ML: new combinators |>> and |>>> for incremental transformations
   338 with secondary results (e.g. certain theory extensions):
   339 
   340 
   341 
   342 New in Isabelle99 (October 1999)
   343 --------------------------------
   344 
   345 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   346 
   347 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   348 are no longer simplified.  (This allows the simplifier to unfold recursive
   349 functional programs.)  To restore the old behaviour, declare
   350 
   351     Delcongs [if_weak_cong];
   352 
   353 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   354 complement;
   355 
   356 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   357 
   358 * HOL/datatype: mutual_induct_tac no longer exists --
   359   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   360 
   361 * HOL/typedef: fixed type inference for representing set; type
   362 arguments now have to occur explicitly on the rhs as type constraints;
   363 
   364 * ZF: The con_defs part of an inductive definition may no longer refer
   365 to constants declared in the same theory;
   366 
   367 * HOL, ZF: the function mk_cases, generated by the inductive
   368 definition package, has lost an argument.  To simplify its result, it
   369 uses the default simpset instead of a supplied list of theorems.
   370 
   371 * HOL/List: the constructors of type list are now Nil and Cons;
   372 
   373 * Simplifier: the type of the infix ML functions
   374         setSSolver addSSolver setSolver addSolver
   375 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   376 for packaging solvers. A solver is created via
   377         mk_solver: string -> (thm list -> int -> tactic) -> solver
   378 where the string argument is only a comment.
   379 
   380 
   381 *** Proof tools ***
   382 
   383 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   384 decision procedure for linear arithmetic. Currently it is used for
   385 types `nat', `int', and `real' in HOL (see below); it can, should and
   386 will be instantiated for other types and logics as well.
   387 
   388 * The simplifier now accepts rewrite rules with flexible heads, eg
   389      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   390   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   391   matching.
   392 
   393 
   394 *** General ***
   395 
   396 * New Isabelle/Isar subsystem provides an alternative to traditional
   397 tactical theorem proving; together with the ProofGeneral/isar user
   398 interface it offers an interactive environment for developing human
   399 readable proof documents (Isar == Intelligible semi-automated
   400 reasoning); for further information see isatool doc isar-ref,
   401 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   402 
   403 * improved and simplified presentation of theories: better HTML markup
   404 (including colors), graph views in several sizes; isatool usedir now
   405 provides a proper interface for user theories (via -P option); actual
   406 document preparation based on (PDF)LaTeX is available as well (for
   407 new-style theories only); see isatool doc system for more information;
   408 
   409 * native support for Proof General, both for classic Isabelle and
   410 Isabelle/Isar;
   411 
   412 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   413 using the graph browser tool;
   414 
   415 * Isabelle manuals now also available as PDF;
   416 
   417 * theory loader rewritten from scratch (may not be fully
   418 bug-compatible); old loadpath variable has been replaced by show_path,
   419 add_path, del_path, reset_path functions; new operations such as
   420 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   421 isatool doc ref);
   422 
   423 * improved isatool install: option -k creates KDE application icon,
   424 option -p DIR installs standalone binaries;
   425 
   426 * added ML_PLATFORM setting (useful for cross-platform installations);
   427 more robust handling of platform specific ML images for SML/NJ;
   428 
   429 * the settings environment is now statically scoped, i.e. it is never
   430 created again in sub-processes invoked from isabelle, isatool, or
   431 Isabelle;
   432 
   433 * path element specification '~~' refers to '$ISABELLE_HOME';
   434 
   435 * in locales, the "assumes" and "defines" parts may be omitted if
   436 empty;
   437 
   438 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   439 long arrows);
   440 
   441 * new print_mode "HTML";
   442 
   443 * new flag show_tags controls display of tags of theorems (which are
   444 basically just comments that may be attached by some tools);
   445 
   446 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   447 mode and goal output format:
   448 
   449 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   450 244c244
   451 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   452 ---
   453 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   454 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   455 181c181
   456 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   457 ---
   458 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   459 
   460 * function bind_thms stores lists of theorems (cf. bind_thm);
   461 
   462 * new shorthand tactics ftac, eatac, datac, fatac;
   463 
   464 * qed (and friends) now accept "" as result name; in that case the
   465 theorem is not stored, but proper checks and presentation of the
   466 result still apply;
   467 
   468 * theorem database now also indexes constants "Trueprop", "all",
   469 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   470 
   471 
   472 *** HOL ***
   473 
   474 ** HOL arithmetic **
   475 
   476 * There are now decision procedures for linear arithmetic over nat and
   477 int:
   478 
   479 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   480 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   481 are treated as atomic; subformulae not involving type `nat' or `int'
   482 are ignored; quantified subformulae are ignored unless they are
   483 positive universal or negative existential. The tactic has to be
   484 invoked by hand and can be a little bit slow. In particular, the
   485 running time is exponential in the number of occurrences of `min' and
   486 `max', and `-' on `nat'.
   487 
   488 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   489 (negated) (in)equalities among the premises and the conclusion into
   490 account (i.e. no compound formulae) and does not know about `min' and
   491 `max', and `-' on `nat'. It is fast and is used automatically by the
   492 simplifier.
   493 
   494 NB: At the moment, these decision procedures do not cope with mixed
   495 nat/int formulae where the two parts interact, such as `m < n ==>
   496 int(m) < int(n)'.
   497 
   498 * HOL/Numeral provides a generic theory of numerals (encoded
   499 efficiently as bit strings); setup for types nat/int/real is in place;
   500 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   501 int, existing theories and proof scripts may require a few additional
   502 type constraints;
   503 
   504 * integer division and remainder can now be performed on constant
   505 arguments;
   506 
   507 * many properties of integer multiplication, division and remainder
   508 are now available;
   509 
   510 * An interface to the Stanford Validity Checker (SVC) is available through the
   511 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   512 are proved automatically.  SVC must be installed separately, and its results
   513 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   514 invocation of the underlying oracle).  For SVC see
   515   http://verify.stanford.edu/SVC
   516 
   517 * IsaMakefile: the HOL-Real target now builds an actual image;
   518 
   519 
   520 ** HOL misc **
   521 
   522 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   523 (in Isabelle/Isar) -- by Gertrud Bauer;
   524 
   525 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   526 analysis for assembly languages with subtypes;
   527 
   528 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   529 -- avoids syntactic ambiguities and treats state, transition, and
   530 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   531 changed syntax and (many) tactics;
   532 
   533 * HOL/inductive: Now also handles more general introduction rules such
   534   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   535   theorems are now maintained within the theory (maintained via the
   536   "mono" attribute);
   537 
   538 * HOL/datatype: Now also handles arbitrarily branching datatypes
   539   (using function types) such as
   540 
   541   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   542 
   543 * HOL/record: record_simproc (part of the default simpset) takes care
   544 of selectors applied to updated records; record_split_tac is no longer
   545 part of the default claset; update_defs may now be removed from the
   546 simpset in many cases; COMPATIBILITY: old behavior achieved by
   547 
   548   claset_ref () := claset() addSWrapper record_split_wrapper;
   549   Delsimprocs [record_simproc]
   550 
   551 * HOL/typedef: fixed type inference for representing set; type
   552 arguments now have to occur explicitly on the rhs as type constraints;
   553 
   554 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   555 names rather than an ML expression;
   556 
   557 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   558 supplied later.  Program schemes can be defined, such as
   559     "While B C s = (if B s then While B C (C s) else s)"
   560 where the well-founded relation can be chosen after B and C have been given.
   561 
   562 * HOL/List: the constructors of type list are now Nil and Cons;
   563 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   564 course, ML tools referring to List.list.op # etc. have to be adapted;
   565 
   566 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   567 disabled by default; run isabelle with option -m HOL to get back to
   568 the original Gordon/HOL-style output;
   569 
   570 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   571 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   572 
   573 * HOL basic syntax simplified (more orthogonal): all variants of
   574 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   575 Eps operator is provided as well: "SOME x. P[x]";
   576 
   577 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   578 
   579 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   580 thus available for user theories;
   581 
   582 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   583 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   584 time;
   585 
   586 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   587 several times and then mp;
   588 
   589 
   590 *** LK ***
   591 
   592 * the notation <<...>> is now available as a notation for sequences of
   593 formulas;
   594 
   595 * the simplifier is now installed
   596 
   597 * the axiom system has been generalized (thanks to Soren Heilmann)
   598 
   599 * the classical reasoner now has a default rule database
   600 
   601 
   602 *** ZF ***
   603 
   604 * new primrec section allows primitive recursive functions to be given
   605 directly (as in HOL) over datatypes and the natural numbers;
   606 
   607 * new tactics induct_tac and exhaust_tac for induction (or case
   608 analysis) over datatypes and the natural numbers;
   609 
   610 * the datatype declaration of type T now defines the recursor T_rec;
   611 
   612 * simplification automatically does freeness reasoning for datatype
   613 constructors;
   614 
   615 * automatic type-inference, with AddTCs command to insert new
   616 type-checking rules;
   617 
   618 * datatype introduction rules are now added as Safe Introduction rules
   619 to the claset;
   620 
   621 * the syntax "if P then x else y" is now available in addition to
   622 if(P,x,y);
   623 
   624 
   625 *** Internal programming interfaces ***
   626 
   627 * tuned simplifier trace output; new flag debug_simp;
   628 
   629 * structures Vartab / Termtab (instances of TableFun) offer efficient
   630 tables indexed by indexname_ord / term_ord (compatible with aconv);
   631 
   632 * AxClass.axclass_tac lost the theory argument;
   633 
   634 * tuned current_goals_markers semantics: begin / end goal avoids
   635 printing empty lines;
   636 
   637 * removed prs and prs_fn hook, which was broken because it did not
   638 include \n in its semantics, forcing writeln to add one
   639 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   640 string -> unit if you really want to output text without newline;
   641 
   642 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   643 plain output, interface builders may have to enable 'isabelle_font'
   644 mode to get Isabelle font glyphs as before;
   645 
   646 * refined token_translation interface; INCOMPATIBILITY: output length
   647 now of type real instead of int;
   648 
   649 * theory loader actions may be traced via new ThyInfo.add_hook
   650 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   651 your own database of information attached to *whole* theories -- as
   652 opposed to intra-theory data slots offered via TheoryDataFun;
   653 
   654 * proper handling of dangling sort hypotheses (at last!);
   655 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   656 extra sort hypotheses that can be witnessed from the type signature;
   657 the force_strip_shyps flag is gone, any remaining shyps are simply
   658 left in the theorem (with a warning issued by strip_shyps_warning);
   659 
   660 
   661 
   662 New in Isabelle98-1 (October 1998)
   663 ----------------------------------
   664 
   665 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   666 
   667 * several changes of automated proof tools;
   668 
   669 * HOL: major changes to the inductive and datatype packages, including
   670 some minor incompatibilities of theory syntax;
   671 
   672 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   673 called `inj_on';
   674 
   675 * HOL: removed duplicate thms in Arith:
   676   less_imp_add_less  should be replaced by  trans_less_add1
   677   le_imp_add_le      should be replaced by  trans_le_add1
   678 
   679 * HOL: unary minus is now overloaded (new type constraints may be
   680 required);
   681 
   682 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   683 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   684 now taken as an integer constant.
   685 
   686 * Pure: ML function 'theory_of' renamed to 'theory';
   687 
   688 
   689 *** Proof tools ***
   690 
   691 * Simplifier:
   692   1. Asm_full_simp_tac is now more aggressive.
   693      1. It will sometimes reorient premises if that increases their power to
   694         simplify.
   695      2. It does no longer proceed strictly from left to right but may also
   696         rotate premises to achieve further simplification.
   697      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   698      old Asm_full_simp_tac in that it does not rotate premises.
   699   2. The simplifier now knows a little bit about nat-arithmetic.
   700 
   701 * Classical reasoner: wrapper mechanism for the classical reasoner now
   702 allows for selected deletion of wrappers, by introduction of names for
   703 wrapper functionals.  This implies that addbefore, addSbefore,
   704 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   705 and that adding two tactics with the same name overwrites the first
   706 one (emitting a warning).
   707   type wrapper = (int -> tactic) -> (int -> tactic)
   708   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   709   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   710   delWrapper, delSWrapper: claset *  string            -> claset
   711   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   712 
   713 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   714 semantics; addbefore now affects only the unsafe part of step_tac
   715 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   716 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   717 by Force_tac;
   718 
   719 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   720 compWrapper; added safe wrapper (and access functions for it);
   721 
   722 * HOL/split_all_tac is now much faster and fails if there is nothing
   723 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   724 and the names of the automatically generated variables have changed.
   725 split_all_tac has moved within claset() from unsafe wrappers to safe
   726 wrappers, which means that !!-bound variables are split much more
   727 aggressively, and safe_tac and clarify_tac now split such variables.
   728 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   729 Note: the same holds for record_split_tac, which does the job of
   730 split_all_tac for record fields.
   731 
   732 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   733 permanently to the default simpset using Addsplits just like
   734 Addsimps. They can be removed via Delsplits just like
   735 Delsimps. Lower-case versions are also available.
   736 
   737 * HOL/Simplifier: The rule split_if is now part of the default
   738 simpset. This means that the simplifier will eliminate all occurrences
   739 of if-then-else in the conclusion of a goal. To prevent this, you can
   740 either remove split_if completely from the default simpset by
   741 `Delsplits [split_if]' or remove it in a specific call of the
   742 simplifier using `... delsplits [split_if]'.  You can also add/delete
   743 other case splitting rules to/from the default simpset: every datatype
   744 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   745 t is the name of the datatype).
   746 
   747 * Classical reasoner / Simplifier combination: new force_tac (and
   748 derivatives Force_tac, force) combines rewriting and classical
   749 reasoning (and whatever other tools) similarly to auto_tac, but is
   750 aimed to solve the given subgoal completely.
   751 
   752 
   753 *** General ***
   754 
   755 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   756 and `goalw': the theory is no longer needed as an explicit argument -
   757 the current theory context is used; assumptions are no longer returned
   758 at the ML-level unless one of them starts with ==> or !!; it is
   759 recommended to convert to these new commands using isatool fixgoal
   760 (backup your sources first!);
   761 
   762 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   763 the current theory context, and 'theory' to lookup stored theories;
   764 
   765 * new theory section 'locale' for declaring constants, assumptions and
   766 definitions that have local scope;
   767 
   768 * new theory section 'nonterminals' for purely syntactic types;
   769 
   770 * new theory section 'setup' for generic ML setup functions
   771 (e.g. package initialization);
   772 
   773 * the distribution now includes Isabelle icons: see
   774 lib/logo/isabelle-{small,tiny}.xpm;
   775 
   776 * isatool install - install binaries with absolute references to
   777 ISABELLE_HOME/bin;
   778 
   779 * isatool logo -- create instances of the Isabelle logo (as EPS);
   780 
   781 * print mode 'emacs' reserved for Isamode;
   782 
   783 * support multiple print (ast) translations per constant name;
   784 
   785 * theorems involving oracles are now printed with a suffixed [!];
   786 
   787 
   788 *** HOL ***
   789 
   790 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   791 
   792 * HOL/inductive package reorganized and improved: now supports mutual
   793 definitions such as
   794 
   795   inductive EVEN ODD
   796     intrs
   797       null "0 : EVEN"
   798       oddI "n : EVEN ==> Suc n : ODD"
   799       evenI "n : ODD ==> Suc n : EVEN"
   800 
   801 new theorem list "elims" contains an elimination rule for each of the
   802 recursive sets; inductive definitions now handle disjunctive premises
   803 correctly (also ZF);
   804 
   805 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   806 "mutual_induct" no longer exists - the induction rule is always
   807 contained in "induct";
   808 
   809 
   810 * HOL/datatype package re-implemented and greatly improved: now
   811 supports mutually recursive datatypes such as
   812 
   813   datatype
   814     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   815             | SUM ('a aexp) ('a aexp)
   816             | DIFF ('a aexp) ('a aexp)
   817             | NUM 'a
   818   and
   819     'a bexp = LESS ('a aexp) ('a aexp)
   820             | AND ('a bexp) ('a bexp)
   821             | OR ('a bexp) ('a bexp)
   822 
   823 as well as indirectly recursive datatypes such as
   824 
   825   datatype
   826     ('a, 'b) term = Var 'a
   827                   | App 'b ((('a, 'b) term) list)
   828 
   829 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   830 induction on mutually / indirectly recursive datatypes.
   831 
   832 Primrec equations are now stored in theory and can be accessed via
   833 <function_name>.simps.
   834 
   835 INCOMPATIBILITIES:
   836 
   837   - Theories using datatypes must now have theory Datatype as an
   838     ancestor.
   839   - The specific <typename>.induct_tac no longer exists - use the
   840     generic induct_tac instead.
   841   - natE has been renamed to nat.exhaust - use exhaust_tac
   842     instead of res_inst_tac ... natE. Note that the variable
   843     names in nat.exhaust differ from the names in natE, this
   844     may cause some "fragile" proofs to fail.
   845   - The theorems split_<typename>_case and split_<typename>_case_asm
   846     have been renamed to <typename>.split and <typename>.split_asm.
   847   - Since default sorts of type variables are now handled correctly,
   848     some datatype definitions may have to be annotated with explicit
   849     sort constraints.
   850   - Primrec definitions no longer require function name and type
   851     of recursive argument.
   852 
   853 Consider using isatool fixdatatype to adapt your theories and proof
   854 scripts to the new package (backup your sources first!).
   855 
   856 
   857 * HOL/record package: considerably improved implementation; now
   858 includes concrete syntax for record types, terms, updates; theorems
   859 for surjective pairing and splitting !!-bound record variables; proof
   860 support is as follows:
   861 
   862   1) standard conversions (selectors or updates applied to record
   863 constructor terms) are part of the standard simpset;
   864 
   865   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   866 made part of standard simpset and claset via addIffs;
   867 
   868   3) a tactic for record field splitting (record_split_tac) is part of
   869 the standard claset (addSWrapper);
   870 
   871 To get a better idea about these rules you may retrieve them via
   872 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   873 the name of your record type.
   874 
   875 The split tactic 3) conceptually simplifies by the following rule:
   876 
   877   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   878 
   879 Thus any record variable that is bound by meta-all will automatically
   880 blow up into some record constructor term, consequently the
   881 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   882 solve record problems automatically.
   883 
   884 
   885 * reorganized the main HOL image: HOL/Integ and String loaded by
   886 default; theory Main includes everything;
   887 
   888 * automatic simplification of integer sums and comparisons, using cancellation;
   889 
   890 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   891 
   892 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   893 
   894 * many new identities for unions, intersections, set difference, etc.;
   895 
   896 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   897 called split_if, split_split, split_sum_case and split_nat_case (to go
   898 with add/delsplits);
   899 
   900 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   901 (?x::unit) = (); this is made part of the default simpset, which COULD
   902 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   903 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   904 unit_abs_eta_conv is added in order to counter the effect of
   905 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   906 %u.f();
   907 
   908 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   909 makes more sense);
   910 
   911 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   912   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   913   disjointness reasoning but breaking a few old proofs.
   914 
   915 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   916 to 'converse' from 'inverse' (for compatibility with ZF and some
   917 literature);
   918 
   919 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   920 the well-founded relation;
   921 
   922 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   923     Compl A.  The "Compl" syntax remains available as input syntax for this
   924     release ONLY.
   925 
   926 * HOL/Update: new theory of function updates:
   927     f(a:=b) == %x. if x=a then b else f x
   928 may also be iterated as in f(a:=b,c:=d,...);
   929 
   930 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   931 
   932 * HOL/List:
   933   - new function list_update written xs[i:=v] that updates the i-th
   934     list position. May also be iterated as in xs[i:=a,j:=b,...].
   935   - new function `upt' written [i..j(] which generates the list
   936     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   937     bound write [i..j], which is a shorthand for [i..j+1(].
   938   - new lexicographic orderings and corresponding wellfoundedness theorems.
   939 
   940 * HOL/Arith:
   941   - removed 'pred' (predecessor) function;
   942   - generalized some theorems about n-1;
   943   - many new laws about "div" and "mod";
   944   - new laws about greatest common divisors (see theory ex/Primes);
   945 
   946 * HOL/Relation: renamed the relational operator r^-1 "converse"
   947 instead of "inverse";
   948 
   949 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   950   of the multiset ordering;
   951 
   952 * directory HOL/Real: a construction of the reals using Dedekind cuts
   953   (not included by default);
   954 
   955 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   956 
   957 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   958   programs, i.e. different program variables may have different types.
   959 
   960 * calling (stac rew i) now fails if "rew" has no effect on the goal
   961   [previously, this check worked only if the rewrite rule was unconditional]
   962   Now rew can involve either definitions or equalities (either == or =).
   963 
   964 
   965 *** ZF ***
   966 
   967 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   968   only the theorems proved on ZF.ML;
   969 
   970 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   971   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   972   disjointness reasoning but breaking a few old proofs.
   973 
   974 * ZF/Update: new theory of function updates
   975     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   976   may also be iterated as in f(a:=b,c:=d,...);
   977 
   978 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   979 
   980 * calling (stac rew i) now fails if "rew" has no effect on the goal
   981   [previously, this check worked only if the rewrite rule was unconditional]
   982   Now rew can involve either definitions or equalities (either == or =).
   983 
   984 * case_tac provided for compatibility with HOL
   985     (like the old excluded_middle_tac, but with subgoals swapped)
   986 
   987 
   988 *** Internal programming interfaces ***
   989 
   990 * Pure: several new basic modules made available for general use, see
   991 also src/Pure/README;
   992 
   993 * improved the theory data mechanism to support encapsulation (data
   994 kind name replaced by private Object.kind, acting as authorization
   995 key); new type-safe user interface via functor TheoryDataFun; generic
   996 print_data function becomes basically useless;
   997 
   998 * removed global_names compatibility flag -- all theory declarations
   999 are qualified by default;
  1000 
  1001 * module Pure/Syntax now offers quote / antiquote translation
  1002 functions (useful for Hoare logic etc. with implicit dependencies);
  1003 see HOL/ex/Antiquote for an example use;
  1004 
  1005 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1006 cterm -> thm;
  1007 
  1008 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1009 subgoal;
  1010 
  1011 * Display.print_goals function moved to Locale.print_goals;
  1012 
  1013 * standard print function for goals supports current_goals_markers
  1014 variable for marking begin of proof, end of proof, start of goal; the
  1015 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1016 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1017 for example;
  1018 
  1019 
  1020 
  1021 New in Isabelle98 (January 1998)
  1022 --------------------------------
  1023 
  1024 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1025 
  1026 * changed lexical syntax of terms / types: dots made part of long
  1027 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1028 
  1029 * simpset (and claset) reference variable replaced by functions
  1030 simpset / simpset_ref;
  1031 
  1032 * no longer supports theory aliases (via merge) and non-trivial
  1033 implicit merge of thms' signatures;
  1034 
  1035 * most internal names of constants changed due to qualified names;
  1036 
  1037 * changed Pure/Sequence interface (see Pure/seq.ML);
  1038 
  1039 
  1040 *** General Changes ***
  1041 
  1042 * hierachically structured name spaces (for consts, types, axms, thms
  1043 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1044 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1045 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1046 long_names for fully qualified output names; NOTE: ML programs
  1047 (special tactics, packages etc.) referring to internal names may have
  1048 to be adapted to cope with fully qualified names; in case of severe
  1049 backward campatibility problems try setting 'global_names' at compile
  1050 time to have enrything declared within a flat name space; one may also
  1051 fine tune name declarations in theories via the 'global' and 'local'
  1052 section;
  1053 
  1054 * reimplemented the implicit simpset and claset using the new anytype
  1055 data filed in signatures; references simpset:simpset ref etc. are
  1056 replaced by functions simpset:unit->simpset and
  1057 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1058 to patch your ML files accordingly;
  1059 
  1060 * HTML output now includes theory graph data for display with Java
  1061 applet or isatool browser; data generated automatically via isatool
  1062 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1063 
  1064 * defs may now be conditional; improved rewrite_goals_tac to handle
  1065 conditional equations;
  1066 
  1067 * defs now admits additional type arguments, using TYPE('a) syntax;
  1068 
  1069 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1070 creates a new theory node; implicit merge of thms' signatures is
  1071 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1072 transfer:theory->thm->thm in (rare) cases;
  1073 
  1074 * improved handling of draft signatures / theories; draft thms (and
  1075 ctyps, cterms) are automatically promoted to real ones;
  1076 
  1077 * slightly changed interfaces for oracles: admit many per theory, named
  1078 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1079 
  1080 * print_goals: optional output of const types (set show_consts and
  1081 show_types);
  1082 
  1083 * improved output of warnings (###) and errors (***);
  1084 
  1085 * subgoal_tac displays a warning if the new subgoal has type variables;
  1086 
  1087 * removed old README and Makefiles;
  1088 
  1089 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1090 
  1091 * removed obsolete init_pps and init_database;
  1092 
  1093 * deleted the obsolete tactical STATE, which was declared by
  1094     fun STATE tacfun st = tacfun st st;
  1095 
  1096 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1097 (which abbreviates $HOME);
  1098 
  1099 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1100 use isatool fixseq to adapt your ML programs (this works for fully
  1101 qualified references to the Sequence structure only!);
  1102 
  1103 * use_thy no longer requires writable current directory; it always
  1104 reloads .ML *and* .thy file, if either one is out of date;
  1105 
  1106 
  1107 *** Classical Reasoner ***
  1108 
  1109 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1110 tactics that use classical reasoning to simplify a subgoal without
  1111 splitting it into several subgoals;
  1112 
  1113 * Safe_tac: like safe_tac but uses the default claset;
  1114 
  1115 
  1116 *** Simplifier ***
  1117 
  1118 * added simplification meta rules:
  1119     (asm_)(full_)simplify: simpset -> thm -> thm;
  1120 
  1121 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1122 logics (again);
  1123 
  1124 * added prems argument to simplification procedures;
  1125 
  1126 * HOL, FOL, ZF: added infix function `addsplits':
  1127   instead of `<simpset> setloop (split_tac <thms>)'
  1128   you can simply write `<simpset> addsplits <thms>'
  1129 
  1130 
  1131 *** Syntax ***
  1132 
  1133 * TYPE('a) syntax for type reflection terms;
  1134 
  1135 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1136 
  1137 * pretty printer: changed order of mixfix annotation preference (again!);
  1138 
  1139 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1140 
  1141 
  1142 *** HOL ***
  1143 
  1144 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1145   with `addloop' of the simplifier to faciliate case splitting in premises.
  1146 
  1147 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1148 
  1149 * HOL/Auth: new protocol proofs including some for the Internet
  1150   protocol TLS;
  1151 
  1152 * HOL/Map: new theory of `maps' a la VDM;
  1153 
  1154 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1155 cancelling out common nat summands from =, <, <= (in)equalities, or
  1156 differences; simplification procedures nat_cancel_factor for
  1157 cancelling common factor from =, <, <= (in)equalities over natural
  1158 sums; nat_cancel contains both kinds of procedures, it is installed by
  1159 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1160 
  1161 * HOL/simplifier: terms of the form
  1162   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1163   are rewritten to
  1164   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1165   and those of the form
  1166   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1167   are rewritten to
  1168   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1169 
  1170 * HOL/datatype
  1171   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1172 
  1173   P(t_case f1 ... fn x) =
  1174      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1175         ...
  1176        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1177      )
  1178 
  1179   and a theorem `split_t_case_asm' of the form
  1180 
  1181   P(t_case f1 ... fn x) =
  1182     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1183         ...
  1184        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1185      )
  1186   which can be added to a simpset via `addsplits'. The existing theorems
  1187   expand_list_case and expand_option_case have been renamed to
  1188   split_list_case and split_option_case.
  1189 
  1190 * HOL/Arithmetic:
  1191   - `pred n' is automatically converted to `n-1'.
  1192     Users are strongly encouraged not to use `pred' any longer,
  1193     because it will disappear altogether at some point.
  1194   - Users are strongly encouraged to write "0 < n" rather than
  1195     "n ~= 0". Theorems and proof tools have been modified towards this
  1196     `standard'.
  1197 
  1198 * HOL/Lists:
  1199   the function "set_of_list" has been renamed "set" (and its theorems too);
  1200   the function "nth" now takes its arguments in the reverse order and
  1201   has acquired the infix notation "!" as in "xs!n".
  1202 
  1203 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1204 
  1205 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1206   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1207 
  1208 * HOL/record: extensible records with schematic structural subtyping
  1209 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1210 still lacks various theorems and concrete record syntax;
  1211 
  1212 
  1213 *** HOLCF ***
  1214 
  1215 * removed "axioms" and "generated by" sections;
  1216 
  1217 * replaced "ops" section by extended "consts" section, which is capable of
  1218   handling the continuous function space "->" directly;
  1219 
  1220 * domain package:
  1221   . proves theorems immediately and stores them in the theory,
  1222   . creates hierachical name space,
  1223   . now uses normal mixfix annotations (instead of cinfix...),
  1224   . minor changes to some names and values (for consistency),
  1225   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1226   . separator between mutual domain defs: changed "," to "and",
  1227   . improved handling of sort constraints;  now they have to
  1228     appear on the left-hand side of the equations only;
  1229 
  1230 * fixed LAM <x,y,zs>.b syntax;
  1231 
  1232 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1233 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1234 
  1235 
  1236 *** FOL and ZF ***
  1237 
  1238 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1239   with `addloop' of the simplifier to faciliate case splitting in premises.
  1240 
  1241 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1242 in HOL, they strip ALL and --> from proved theorems;
  1243 
  1244 
  1245 
  1246 New in Isabelle94-8 (May 1997)
  1247 ------------------------------
  1248 
  1249 *** General Changes ***
  1250 
  1251 * new utilities to build / run / maintain Isabelle etc. (in parts
  1252 still somewhat experimental); old Makefiles etc. still functional;
  1253 
  1254 * new 'Isabelle System Manual';
  1255 
  1256 * INSTALL text, together with ./configure and ./build scripts;
  1257 
  1258 * reimplemented type inference for greater efficiency, better error
  1259 messages and clean internal interface;
  1260 
  1261 * prlim command for dealing with lots of subgoals (an easier way of
  1262 setting goals_limit);
  1263 
  1264 
  1265 *** Syntax ***
  1266 
  1267 * supports alternative (named) syntax tables (parser and pretty
  1268 printer); internal interface is provided by add_modesyntax(_i);
  1269 
  1270 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1271 be used in conjunction with the Isabelle symbol font; uses the
  1272 "symbols" syntax table;
  1273 
  1274 * added token_translation interface (may translate name tokens in
  1275 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1276 the current print_mode); IMPORTANT: user print translation functions
  1277 are responsible for marking newly introduced bounds
  1278 (Syntax.mark_boundT);
  1279 
  1280 * token translations for modes "xterm" and "xterm_color" that display
  1281 names in bold, underline etc. or colors (which requires a color
  1282 version of xterm);
  1283 
  1284 * infixes may now be declared with names independent of their syntax;
  1285 
  1286 * added typed_print_translation (like print_translation, but may
  1287 access type of constant);
  1288 
  1289 
  1290 *** Classical Reasoner ***
  1291 
  1292 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1293 some limitations.  Blast_tac...
  1294   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1295   + ignores elimination rules that don't have the correct format
  1296         (the conclusion MUST be a formula variable)
  1297   + ignores types, which can make HOL proofs fail
  1298   + rules must not require higher-order unification, e.g. apply_type in ZF
  1299     [message "Function Var's argument not a bound variable" relates to this]
  1300   + its proof strategy is more general but can actually be slower
  1301 
  1302 * substitution with equality assumptions no longer permutes other
  1303 assumptions;
  1304 
  1305 * minor changes in semantics of addafter (now called addaltern); renamed
  1306 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1307 (and access functions for it);
  1308 
  1309 * improved combination of classical reasoner and simplifier:
  1310   + functions for handling clasimpsets
  1311   + improvement of addss: now the simplifier is called _after_ the
  1312     safe steps.
  1313   + safe variant of addss called addSss: uses safe simplifications
  1314     _during_ the safe steps. It is more complete as it allows multiple
  1315     instantiations of unknowns (e.g. with slow_tac).
  1316 
  1317 *** Simplifier ***
  1318 
  1319 * added interface for simplification procedures (functions that
  1320 produce *proven* rewrite rules on the fly, depending on current
  1321 redex);
  1322 
  1323 * ordering on terms as parameter (used for ordered rewriting);
  1324 
  1325 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1326 
  1327 * the solver is now split into a safe and an unsafe part.
  1328 This should be invisible for the normal user, except that the
  1329 functions setsolver and addsolver have been renamed to setSolver and
  1330 addSolver; added safe_asm_full_simp_tac;
  1331 
  1332 
  1333 *** HOL ***
  1334 
  1335 * a generic induction tactic `induct_tac' which works for all datatypes and
  1336 also for type `nat';
  1337 
  1338 * a generic case distinction tactic `exhaust_tac' which works for all
  1339 datatypes and also for type `nat';
  1340 
  1341 * each datatype comes with a function `size';
  1342 
  1343 * patterns in case expressions allow tuple patterns as arguments to
  1344 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1345 
  1346 * primrec now also works with type nat;
  1347 
  1348 * recdef: a new declaration form, allows general recursive functions to be
  1349 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1350 
  1351 * the constant for negation has been renamed from "not" to "Not" to
  1352 harmonize with FOL, ZF, LK, etc.;
  1353 
  1354 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1355 infinite lists;
  1356 
  1357 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1358 
  1359 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1360 problems in commutative rings, using axiomatic type classes for + and *;
  1361 
  1362 * more examples in HOL/MiniML and HOL/Auth;
  1363 
  1364 * more default rewrite rules for quantifiers, union/intersection;
  1365 
  1366 * a new constant `arbitrary == @x.False';
  1367 
  1368 * HOLCF/IOA replaces old HOL/IOA;
  1369 
  1370 * HOLCF changes: derived all rules and arities
  1371   + axiomatic type classes instead of classes
  1372   + typedef instead of faking type definitions
  1373   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1374   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1375   + eliminated the types void, one, tr
  1376   + use unit lift and bool lift (with translations) instead of one and tr
  1377   + eliminated blift from Lift3.thy (use Def instead of blift)
  1378   all eliminated rules are derived as theorems --> no visible changes ;
  1379 
  1380 
  1381 *** ZF ***
  1382 
  1383 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1384 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1385 as ZF_cs addSIs [equalityI];
  1386 
  1387 
  1388 
  1389 New in Isabelle94-7 (November 96)
  1390 ---------------------------------
  1391 
  1392 * allowing negative levels (as offsets) in prlev and choplev;
  1393 
  1394 * super-linear speedup for large simplifications;
  1395 
  1396 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1397 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1398 FAIL); can suppress it using the command Delsimps (ex_simps @
  1399 all_simps); De Morgan laws are also now included, by default;
  1400 
  1401 * improved printing of ==>  :  ~:
  1402 
  1403 * new object-logic "Sequents" adds linear logic, while replacing LK
  1404 and Modal (thanks to Sara Kalvala);
  1405 
  1406 * HOL/Auth: correctness proofs for authentication protocols;
  1407 
  1408 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1409 examples on HOL/Auth);
  1410 
  1411 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1412 the rewriter and classical reasoner simultaneously;
  1413 
  1414 * function uresult no longer returns theorems in "standard" format;
  1415 regain previous version by: val uresult = standard o uresult;
  1416 
  1417 
  1418 
  1419 New in Isabelle94-6
  1420 -------------------
  1421 
  1422 * oracles -- these establish an interface between Isabelle and trusted
  1423 external reasoners, which may deliver results as theorems;
  1424 
  1425 * proof objects (in particular record all uses of oracles);
  1426 
  1427 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1428 
  1429 * "constdefs" section in theory files;
  1430 
  1431 * "primrec" section (HOL) no longer requires names;
  1432 
  1433 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1434 
  1435 
  1436 
  1437 New in Isabelle94-5
  1438 -------------------
  1439 
  1440 * reduced space requirements;
  1441 
  1442 * automatic HTML generation from theories;
  1443 
  1444 * theory files no longer require "..." (quotes) around most types;
  1445 
  1446 * new examples, including two proofs of the Church-Rosser theorem;
  1447 
  1448 * non-curried (1994) version of HOL is no longer distributed;
  1449 
  1450 
  1451 
  1452 New in Isabelle94-4
  1453 -------------------
  1454 
  1455 * greatly reduced space requirements;
  1456 
  1457 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1458 
  1459 * searchable theorem database (see the section "Retrieving theorems" on
  1460 page 8 of the Reference Manual);
  1461 
  1462 * new examples, including Grabczewski's monumental case study of the
  1463 Axiom of Choice;
  1464 
  1465 * The previous version of HOL renamed to Old_HOL;
  1466 
  1467 * The new version of HOL (previously called CHOL) uses a curried syntax
  1468 for functions.  Application looks like f a b instead of f(a,b);
  1469 
  1470 * Mutually recursive inductive definitions finally work in HOL;
  1471 
  1472 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1473 translates to the operator "split";
  1474 
  1475 
  1476 
  1477 New in Isabelle94-3
  1478 -------------------
  1479 
  1480 * new infix operator, addss, allowing the classical reasoner to
  1481 perform simplification at each step of its search.  Example:
  1482         fast_tac (cs addss ss)
  1483 
  1484 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1485 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1486 look like (a,b) instead of <a,b>;
  1487 
  1488 * PLEASE NOTE: CHOL will eventually replace HOL!
  1489 
  1490 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1491 It translates to the operator "split".  A new theory of integers is available;
  1492 
  1493 * In ZF, integer numerals now denote two's-complement binary integers.
  1494 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1495 
  1496 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1497 of the Axiom of Choice;
  1498 
  1499 
  1500 
  1501 New in Isabelle94-2
  1502 -------------------
  1503 
  1504 * Significantly faster resolution;
  1505 
  1506 * the different sections in a .thy file can now be mixed and repeated
  1507 freely;
  1508 
  1509 * Database of theorems for FOL, HOL and ZF.  New
  1510 commands including qed, qed_goal and bind_thm store theorems in the database.
  1511 
  1512 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1513 a given theory (thms_of), or find out what theory a theorem was proved in
  1514 (theory_of_thm);
  1515 
  1516 * Bugs fixed in the inductive definition and datatype packages;
  1517 
  1518 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1519 and HOL_dup_cs obsolete;
  1520 
  1521 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1522 have been removed;
  1523 
  1524 * Simpler definition of function space in ZF;
  1525 
  1526 * new results about cardinal and ordinal arithmetic in ZF;
  1527 
  1528 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1529 types;
  1530 
  1531 
  1532 $Id$