NEWS
author wenzelm
Sun May 28 21:55:50 2000 +0200 (2000-05-28)
changeset 8991 dc70b797827f
parent 8967 00f18476ac15
child 8994 803533fbb3ec
permissions -rw-r--r--
case 'antecedent';
     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 cartesian product is now "<*>" instead of "Times"; the
    23 lexicographic product is now "<*lex*>" instead of "**";
    24 
    25 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    26 
    27 * HOL: simplification no longer dives into case-expressions
    28 
    29 * HOL: the recursion equations generated by 'recdef' are now called
    30 f.simps instead of f.rules;
    31 
    32 * HOL: theory Sexp now in HOL/Induct examples (used to be part of main
    33 HOL, but was unused); should better use HOL's datatype package anyway;
    34 
    35 * HOL/Real: "rabs" replaced by overloaded "abs" function;
    36 
    37 * HOL/ML: even fewer consts are declared as global (see theories Ord,
    38 Lfp, Gfp, WF); this only affects ML packages that refer to const names
    39 internally;
    40 
    41 * Isar: changed syntax of local blocks from {{ }} to { };
    42 
    43 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    44 
    45 * LaTeX: several improvements of isabelle.sty;
    46 
    47 
    48 *** Document preparation ***
    49 
    50 * isatool mkdir provides easy setup of Isabelle session directories,
    51 including proper document sources;
    52 
    53 * generated LaTeX sources are now deleted after successful run
    54 (isatool document -c); may retain a copy somewhere else via -D option
    55 of isatool usedir;
    56 
    57 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    58 style files, achieving self-contained LaTeX sources;
    59 
    60 * old-style theories now produce (crude) LaTeX output as well;
    61 
    62 
    63 *** Isar ***
    64 
    65 * Pure: local results and corresponding term bindings are now subject
    66 to Hindley-Milner polymorphism (similar to ML); this accommodates
    67 incremental type-inference nicely;
    68 
    69 * Pure: new 'obtain' language element supports generalized existence
    70 reasoning;
    71 
    72 * Pure: new calculational elements 'moreover' and 'ultimately' support
    73 plain accumulation of results, without applying any rules yet;
    74 
    75 * Pure: scalable support for case-analysis type proofs: new 'case'
    76 language element refers to local contexts symbolically, as produced by
    77 certain proof methods; internally, case names are attached to theorems
    78 as "tags";
    79 
    80 * Pure: changed syntax of local blocks from {{ }} to { };
    81 
    82 * Pure: syntax of sorts made inner, i.e. have to write "{a, b, c}"
    83 instead of {a, b, c};
    84 
    85 * Pure now provides its own version of intro/elim/dest attributes;
    86 useful for building new logics, but beware of confusion with the
    87 Provers/classical ones;
    88 
    89 * Pure: the local context of (non-atomic) goals is provided via case
    90 name 'antecedent';
    91 
    92 * Provers: splitter support (via 'split' attribute and 'simp' method
    93 modifier); 'simp' method: 'only:' modifier removes loopers as well
    94 (including splits);
    95 
    96 * HOL: new proof method 'cases' and improved version of 'induct' now
    97 support named cases; major packages (inductive, datatype, primrec,
    98 recdef) support case names and properly name parameters;
    99 
   100 * HOL: removed 'case_split' thm binding, should use 'cases' proof
   101 method anyway;
   102 
   103 * names of theorems etc. may be natural numbers as well;
   104 
   105 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
   106 
   107 * 'pr' command: optional goals_limit argument; no longer prints theory
   108 contexts, but only proof states;
   109 
   110 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   111 additional print modes to be specified; e.g. "pr(latex)" will print
   112 proof state according to the Isabelle LaTeX style;
   113 
   114 * improved support for emulating tactic scripts, including proof
   115 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
   116 'induct_tac' (for HOL datatypes);
   117 
   118 * simplified (more robust) goal selection of proof methods: 1st goal,
   119 all goals, or explicit goal specifier (tactic emulation); thus 'proof
   120 method scripts' have to be in depth-first order;
   121 
   122 * tuned 'let' syntax: replace 'as' keyword by 'and';
   123 
   124 * theory command 'hide' removes declarations from class/type/const
   125 name spaces;
   126 
   127 
   128 *** HOL ***
   129 
   130 * HOL/Algebra: new theory of rings and univariate polynomials, by
   131 Clemens Ballarin;
   132 
   133 * HOL/record: fixed select-update simplification procedure to handle
   134 extended records as well; admit "r" as field name;
   135 
   136 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
   137 Arithmetic, by Thomas M Rasmussen;
   138 
   139 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
   140 basically a generalized version of de-Bruijn representation; very
   141 useful in avoiding lifting all operations;
   142 
   143 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   144 
   145 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   146 other numeric types and also as the identity of groups, rings, etc.;
   147 
   148 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   149 Types nat and int belong to this axclass;
   150 
   151 * greatly improved simplification involving numerals of type nat & int, e.g.
   152    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   153    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   154   two terms #m*u and #n*u are replaced by #(m+n)*u
   155     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   156   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   157     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   158 
   159 * HOL: new version of "case_tac" subsumes both boolean case split and
   160 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   161 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   162 
   163 * HOL: simplification no longer dives into case-expressions: only the
   164 selector expression is simplified, but not the remaining arms. To
   165 enable full simplification of case-expressions for datatype t, you
   166 need to remove t.weak_case_cong from the simpset, either permanently
   167 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   168 
   169 * HOL/recdef: the recursion equations generated by 'recdef' for
   170 function 'f' are now called f.simps instead of f.rules; if all
   171 termination conditions are proved automatically, these simplification
   172 rules are added to the simpset, as in primrec; rules may be named
   173 individually as well, resulting in a separate list of theorems for
   174 each equation;
   175 
   176 * HOL: new (overloaded) notation for the set of elements below/above some
   177 element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   178 
   179 * HOL: theorems impI, allI, ballI bound as "strip";
   180 
   181 * theory Sexp now in HOL/Induct examples (used to be part of main HOL,
   182 but was unused);
   183 
   184 * fewer consts declared as global (e.g. have to refer to "Lfp.lfp"
   185 instead of "lfp" internally; affects ML packages only);
   186 
   187 
   188 *** General ***
   189 
   190 * improved name spaces: ambiguous output is qualified; support for
   191 hiding of names;
   192 
   193 * compression of ML heaps images may now be controlled via -c option
   194 of isabelle and isatool usedir (currently only observed by Poly/ML);
   195 
   196 * ML: new combinators |>> and |>>> for incremental transformations
   197 with secondary results (e.g. certain theory extensions):
   198 
   199 
   200 
   201 New in Isabelle99 (October 1999)
   202 --------------------------------
   203 
   204 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   205 
   206 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   207 are no longer simplified.  (This allows the simplifier to unfold recursive
   208 functional programs.)  To restore the old behaviour, declare
   209 
   210     Delcongs [if_weak_cong];
   211 
   212 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   213 complement;
   214 
   215 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   216 
   217 * HOL/datatype: mutual_induct_tac no longer exists --
   218   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   219 
   220 * HOL/typedef: fixed type inference for representing set; type
   221 arguments now have to occur explicitly on the rhs as type constraints;
   222 
   223 * ZF: The con_defs part of an inductive definition may no longer refer
   224 to constants declared in the same theory;
   225 
   226 * HOL, ZF: the function mk_cases, generated by the inductive
   227 definition package, has lost an argument.  To simplify its result, it
   228 uses the default simpset instead of a supplied list of theorems.
   229 
   230 * HOL/List: the constructors of type list are now Nil and Cons;
   231 
   232 * Simplifier: the type of the infix ML functions
   233         setSSolver addSSolver setSolver addSolver
   234 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   235 for packaging solvers. A solver is created via
   236         mk_solver: string -> (thm list -> int -> tactic) -> solver
   237 where the string argument is only a comment.
   238 
   239 
   240 *** Proof tools ***
   241 
   242 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   243 decision procedure for linear arithmetic. Currently it is used for
   244 types `nat', `int', and `real' in HOL (see below); it can, should and
   245 will be instantiated for other types and logics as well.
   246 
   247 * The simplifier now accepts rewrite rules with flexible heads, eg
   248      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   249   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   250   matching.
   251 
   252 
   253 *** General ***
   254 
   255 * New Isabelle/Isar subsystem provides an alternative to traditional
   256 tactical theorem proving; together with the ProofGeneral/isar user
   257 interface it offers an interactive environment for developing human
   258 readable proof documents (Isar == Intelligible semi-automated
   259 reasoning); for further information see isatool doc isar-ref,
   260 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   261 
   262 * improved presentation of theories: better HTML markup (including
   263 colors), graph views in several sizes; isatool usedir now provides a
   264 proper interface for user theories (via -P option); actual document
   265 preparation based on (PDF)LaTeX is available as well (for new-style
   266 theories only); see isatool doc system for more information;
   267 
   268 * native support for Proof General, both for classic Isabelle and
   269 Isabelle/Isar;
   270 
   271 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   272 using the graph browser tool;
   273 
   274 * Isabelle manuals now also available as PDF;
   275 
   276 * theory loader rewritten from scratch (may not be fully
   277 bug-compatible); old loadpath variable has been replaced by show_path,
   278 add_path, del_path, reset_path functions; new operations such as
   279 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   280 isatool doc ref);
   281 
   282 * improved isatool install: option -k creates KDE application icon,
   283 option -p DIR installs standalone binaries;
   284 
   285 * added ML_PLATFORM setting (useful for cross-platform installations);
   286 more robust handling of platform specific ML images for SML/NJ;
   287 
   288 * the settings environment is now statically scoped, i.e. it is never
   289 created again in sub-processes invoked from isabelle, isatool, or
   290 Isabelle;
   291 
   292 * path element specification '~~' refers to '$ISABELLE_HOME';
   293 
   294 * in locales, the "assumes" and "defines" parts may be omitted if
   295 empty;
   296 
   297 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   298 long arrows);
   299 
   300 * new print_mode "HTML";
   301 
   302 * new flag show_tags controls display of tags of theorems (which are
   303 basically just comments that may be attached by some tools);
   304 
   305 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   306 mode and goal output format:
   307 
   308 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   309 244c244
   310 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   311 ---
   312 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   313 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   314 181c181
   315 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   316 ---
   317 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   318 
   319 * function bind_thms stores lists of theorems (cf. bind_thm);
   320 
   321 * new shorthand tactics ftac, eatac, datac, fatac;
   322 
   323 * qed (and friends) now accept "" as result name; in that case the
   324 theorem is not stored, but proper checks and presentation of the
   325 result still apply;
   326 
   327 * theorem database now also indexes constants "Trueprop", "all",
   328 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   329 
   330 
   331 *** HOL ***
   332 
   333 ** HOL arithmetic **
   334 
   335 * There are now decision procedures for linear arithmetic over nat and
   336 int:
   337 
   338 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   339 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   340 are treated as atomic; subformulae not involving type `nat' or `int'
   341 are ignored; quantified subformulae are ignored unless they are
   342 positive universal or negative existential. The tactic has to be
   343 invoked by hand and can be a little bit slow. In particular, the
   344 running time is exponential in the number of occurrences of `min' and
   345 `max', and `-' on `nat'.
   346 
   347 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   348 (negated) (in)equalities among the premises and the conclusion into
   349 account (i.e. no compound formulae) and does not know about `min' and
   350 `max', and `-' on `nat'. It is fast and is used automatically by the
   351 simplifier.
   352 
   353 NB: At the moment, these decision procedures do not cope with mixed
   354 nat/int formulae where the two parts interact, such as `m < n ==>
   355 int(m) < int(n)'.
   356 
   357 * HOL/Numeral provides a generic theory of numerals (encoded
   358 efficiently as bit strings); setup for types nat/int/real is in place;
   359 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   360 int, existing theories and proof scripts may require a few additional
   361 type constraints;
   362 
   363 * integer division and remainder can now be performed on constant
   364 arguments;
   365 
   366 * many properties of integer multiplication, division and remainder
   367 are now available;
   368 
   369 * An interface to the Stanford Validity Checker (SVC) is available through the
   370 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   371 are proved automatically.  SVC must be installed separately, and its results
   372 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   373 invocation of the underlying oracle).  For SVC see
   374   http://verify.stanford.edu/SVC
   375 
   376 * IsaMakefile: the HOL-Real target now builds an actual image;
   377 
   378 
   379 ** HOL misc **
   380 
   381 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   382 (in Isabelle/Isar) -- by Gertrud Bauer;
   383 
   384 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   385 analysis for assembly languages with subtypes;
   386 
   387 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   388 -- avoids syntactic ambiguities and treats state, transition, and
   389 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   390 changed syntax and (many) tactics;
   391 
   392 * HOL/inductive: Now also handles more general introduction rules such
   393   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   394   theorems are now maintained within the theory (maintained via the
   395   "mono" attribute);
   396 
   397 * HOL/datatype: Now also handles arbitrarily branching datatypes
   398   (using function types) such as
   399 
   400   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   401 
   402 * HOL/record: record_simproc (part of the default simpset) takes care
   403 of selectors applied to updated records; record_split_tac is no longer
   404 part of the default claset; update_defs may now be removed from the
   405 simpset in many cases; COMPATIBILITY: old behavior achieved by
   406 
   407   claset_ref () := claset() addSWrapper record_split_wrapper;
   408   Delsimprocs [record_simproc]
   409 
   410 * HOL/typedef: fixed type inference for representing set; type
   411 arguments now have to occur explicitly on the rhs as type constraints;
   412 
   413 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   414 names rather than an ML expression;
   415 
   416 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   417 supplied later.  Program schemes can be defined, such as
   418     "While B C s = (if B s then While B C (C s) else s)"
   419 where the well-founded relation can be chosen after B and C have been given.
   420 
   421 * HOL/List: the constructors of type list are now Nil and Cons;
   422 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   423 course, ML tools referring to List.list.op # etc. have to be adapted;
   424 
   425 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   426 disabled by default; run isabelle with option -m HOL to get back to
   427 the original Gordon/HOL-style output;
   428 
   429 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   430 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   431 
   432 * HOL basic syntax simplified (more orthogonal): all variants of
   433 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   434 Eps operator is provided as well: "SOME x. P[x]";
   435 
   436 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   437 
   438 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   439 thus available for user theories;
   440 
   441 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   442 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   443 time;
   444 
   445 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   446 several times and then mp;
   447 
   448 
   449 *** LK ***
   450 
   451 * the notation <<...>> is now available as a notation for sequences of
   452 formulas;
   453 
   454 * the simplifier is now installed
   455 
   456 * the axiom system has been generalized (thanks to Soren Heilmann)
   457 
   458 * the classical reasoner now has a default rule database
   459 
   460 
   461 *** ZF ***
   462 
   463 * new primrec section allows primitive recursive functions to be given
   464 directly (as in HOL) over datatypes and the natural numbers;
   465 
   466 * new tactics induct_tac and exhaust_tac for induction (or case
   467 analysis) over datatypes and the natural numbers;
   468 
   469 * the datatype declaration of type T now defines the recursor T_rec;
   470 
   471 * simplification automatically does freeness reasoning for datatype
   472 constructors;
   473 
   474 * automatic type-inference, with AddTCs command to insert new
   475 type-checking rules;
   476 
   477 * datatype introduction rules are now added as Safe Introduction rules
   478 to the claset;
   479 
   480 * the syntax "if P then x else y" is now available in addition to
   481 if(P,x,y);
   482 
   483 
   484 *** Internal programming interfaces ***
   485 
   486 * tuned simplifier trace output; new flag debug_simp;
   487 
   488 * structures Vartab / Termtab (instances of TableFun) offer efficient
   489 tables indexed by indexname_ord / term_ord (compatible with aconv);
   490 
   491 * AxClass.axclass_tac lost the theory argument;
   492 
   493 * tuned current_goals_markers semantics: begin / end goal avoids
   494 printing empty lines;
   495 
   496 * removed prs and prs_fn hook, which was broken because it did not
   497 include \n in its semantics, forcing writeln to add one
   498 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   499 string -> unit if you really want to output text without newline;
   500 
   501 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   502 plain output, interface builders may have to enable 'isabelle_font'
   503 mode to get Isabelle font glyphs as before;
   504 
   505 * refined token_translation interface; INCOMPATIBILITY: output length
   506 now of type real instead of int;
   507 
   508 * theory loader actions may be traced via new ThyInfo.add_hook
   509 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   510 your own database of information attached to *whole* theories -- as
   511 opposed to intra-theory data slots offered via TheoryDataFun;
   512 
   513 * proper handling of dangling sort hypotheses (at last!);
   514 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   515 extra sort hypotheses that can be witnessed from the type signature;
   516 the force_strip_shyps flag is gone, any remaining shyps are simply
   517 left in the theorem (with a warning issued by strip_shyps_warning);
   518 
   519 
   520 
   521 New in Isabelle98-1 (October 1998)
   522 ----------------------------------
   523 
   524 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   525 
   526 * several changes of automated proof tools;
   527 
   528 * HOL: major changes to the inductive and datatype packages, including
   529 some minor incompatibilities of theory syntax;
   530 
   531 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   532 called `inj_on';
   533 
   534 * HOL: removed duplicate thms in Arith:
   535   less_imp_add_less  should be replaced by  trans_less_add1
   536   le_imp_add_le      should be replaced by  trans_le_add1
   537 
   538 * HOL: unary minus is now overloaded (new type constraints may be
   539 required);
   540 
   541 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   542 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   543 now taken as an integer constant.
   544 
   545 * Pure: ML function 'theory_of' renamed to 'theory';
   546 
   547 
   548 *** Proof tools ***
   549 
   550 * Simplifier:
   551   1. Asm_full_simp_tac is now more aggressive.
   552      1. It will sometimes reorient premises if that increases their power to
   553         simplify.
   554      2. It does no longer proceed strictly from left to right but may also
   555         rotate premises to achieve further simplification.
   556      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   557      old Asm_full_simp_tac in that it does not rotate premises.
   558   2. The simplifier now knows a little bit about nat-arithmetic.
   559 
   560 * Classical reasoner: wrapper mechanism for the classical reasoner now
   561 allows for selected deletion of wrappers, by introduction of names for
   562 wrapper functionals.  This implies that addbefore, addSbefore,
   563 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   564 and that adding two tactics with the same name overwrites the first
   565 one (emitting a warning).
   566   type wrapper = (int -> tactic) -> (int -> tactic)
   567   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   568   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   569   delWrapper, delSWrapper: claset *  string            -> claset
   570   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   571 
   572 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   573 semantics; addbefore now affects only the unsafe part of step_tac
   574 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   575 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   576 by Force_tac;
   577 
   578 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   579 compWrapper; added safe wrapper (and access functions for it);
   580 
   581 * HOL/split_all_tac is now much faster and fails if there is nothing
   582 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   583 and the names of the automatically generated variables have changed.
   584 split_all_tac has moved within claset() from unsafe wrappers to safe
   585 wrappers, which means that !!-bound variables are split much more
   586 aggressively, and safe_tac and clarify_tac now split such variables.
   587 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   588 Note: the same holds for record_split_tac, which does the job of
   589 split_all_tac for record fields.
   590 
   591 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   592 permanently to the default simpset using Addsplits just like
   593 Addsimps. They can be removed via Delsplits just like
   594 Delsimps. Lower-case versions are also available.
   595 
   596 * HOL/Simplifier: The rule split_if is now part of the default
   597 simpset. This means that the simplifier will eliminate all occurrences
   598 of if-then-else in the conclusion of a goal. To prevent this, you can
   599 either remove split_if completely from the default simpset by
   600 `Delsplits [split_if]' or remove it in a specific call of the
   601 simplifier using `... delsplits [split_if]'.  You can also add/delete
   602 other case splitting rules to/from the default simpset: every datatype
   603 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   604 t is the name of the datatype).
   605 
   606 * Classical reasoner / Simplifier combination: new force_tac (and
   607 derivatives Force_tac, force) combines rewriting and classical
   608 reasoning (and whatever other tools) similarly to auto_tac, but is
   609 aimed to solve the given subgoal completely.
   610 
   611 
   612 *** General ***
   613 
   614 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   615 and `goalw': the theory is no longer needed as an explicit argument -
   616 the current theory context is used; assumptions are no longer returned
   617 at the ML-level unless one of them starts with ==> or !!; it is
   618 recommended to convert to these new commands using isatool fixgoal
   619 (backup your sources first!);
   620 
   621 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   622 the current theory context, and 'theory' to lookup stored theories;
   623 
   624 * new theory section 'locale' for declaring constants, assumptions and
   625 definitions that have local scope;
   626 
   627 * new theory section 'nonterminals' for purely syntactic types;
   628 
   629 * new theory section 'setup' for generic ML setup functions
   630 (e.g. package initialization);
   631 
   632 * the distribution now includes Isabelle icons: see
   633 lib/logo/isabelle-{small,tiny}.xpm;
   634 
   635 * isatool install - install binaries with absolute references to
   636 ISABELLE_HOME/bin;
   637 
   638 * isatool logo -- create instances of the Isabelle logo (as EPS);
   639 
   640 * print mode 'emacs' reserved for Isamode;
   641 
   642 * support multiple print (ast) translations per constant name;
   643 
   644 * theorems involving oracles are now printed with a suffixed [!];
   645 
   646 
   647 *** HOL ***
   648 
   649 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   650 
   651 * HOL/inductive package reorganized and improved: now supports mutual
   652 definitions such as
   653 
   654   inductive EVEN ODD
   655     intrs
   656       null "0 : EVEN"
   657       oddI "n : EVEN ==> Suc n : ODD"
   658       evenI "n : ODD ==> Suc n : EVEN"
   659 
   660 new theorem list "elims" contains an elimination rule for each of the
   661 recursive sets; inductive definitions now handle disjunctive premises
   662 correctly (also ZF);
   663 
   664 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   665 "mutual_induct" no longer exists - the induction rule is always
   666 contained in "induct";
   667 
   668 
   669 * HOL/datatype package re-implemented and greatly improved: now
   670 supports mutually recursive datatypes such as
   671 
   672   datatype
   673     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   674             | SUM ('a aexp) ('a aexp)
   675             | DIFF ('a aexp) ('a aexp)
   676             | NUM 'a
   677   and
   678     'a bexp = LESS ('a aexp) ('a aexp)
   679             | AND ('a bexp) ('a bexp)
   680             | OR ('a bexp) ('a bexp)
   681 
   682 as well as indirectly recursive datatypes such as
   683 
   684   datatype
   685     ('a, 'b) term = Var 'a
   686                   | App 'b ((('a, 'b) term) list)
   687 
   688 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   689 induction on mutually / indirectly recursive datatypes.
   690 
   691 Primrec equations are now stored in theory and can be accessed via
   692 <function_name>.simps.
   693 
   694 INCOMPATIBILITIES:
   695 
   696   - Theories using datatypes must now have theory Datatype as an
   697     ancestor.
   698   - The specific <typename>.induct_tac no longer exists - use the
   699     generic induct_tac instead.
   700   - natE has been renamed to nat.exhaust - use exhaust_tac
   701     instead of res_inst_tac ... natE. Note that the variable
   702     names in nat.exhaust differ from the names in natE, this
   703     may cause some "fragile" proofs to fail.
   704   - The theorems split_<typename>_case and split_<typename>_case_asm
   705     have been renamed to <typename>.split and <typename>.split_asm.
   706   - Since default sorts of type variables are now handled correctly,
   707     some datatype definitions may have to be annotated with explicit
   708     sort constraints.
   709   - Primrec definitions no longer require function name and type
   710     of recursive argument.
   711 
   712 Consider using isatool fixdatatype to adapt your theories and proof
   713 scripts to the new package (backup your sources first!).
   714 
   715 
   716 * HOL/record package: considerably improved implementation; now
   717 includes concrete syntax for record types, terms, updates; theorems
   718 for surjective pairing and splitting !!-bound record variables; proof
   719 support is as follows:
   720 
   721   1) standard conversions (selectors or updates applied to record
   722 constructor terms) are part of the standard simpset;
   723 
   724   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   725 made part of standard simpset and claset via addIffs;
   726 
   727   3) a tactic for record field splitting (record_split_tac) is part of
   728 the standard claset (addSWrapper);
   729 
   730 To get a better idea about these rules you may retrieve them via
   731 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   732 the name of your record type.
   733 
   734 The split tactic 3) conceptually simplifies by the following rule:
   735 
   736   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   737 
   738 Thus any record variable that is bound by meta-all will automatically
   739 blow up into some record constructor term, consequently the
   740 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   741 solve record problems automatically.
   742 
   743 
   744 * reorganized the main HOL image: HOL/Integ and String loaded by
   745 default; theory Main includes everything;
   746 
   747 * automatic simplification of integer sums and comparisons, using cancellation;
   748 
   749 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   750 
   751 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   752 
   753 * many new identities for unions, intersections, set difference, etc.;
   754 
   755 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   756 called split_if, split_split, split_sum_case and split_nat_case (to go
   757 with add/delsplits);
   758 
   759 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   760 (?x::unit) = (); this is made part of the default simpset, which COULD
   761 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   762 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   763 unit_abs_eta_conv is added in order to counter the effect of
   764 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   765 %u.f();
   766 
   767 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   768 makes more sense);
   769 
   770 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   771   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   772   disjointness reasoning but breaking a few old proofs.
   773 
   774 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   775 to 'converse' from 'inverse' (for compatibility with ZF and some
   776 literature);
   777 
   778 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   779 the well-founded relation;
   780 
   781 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   782     Compl A.  The "Compl" syntax remains available as input syntax for this
   783     release ONLY.
   784 
   785 * HOL/Update: new theory of function updates:
   786     f(a:=b) == %x. if x=a then b else f x
   787 may also be iterated as in f(a:=b,c:=d,...);
   788 
   789 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   790 
   791 * HOL/List:
   792   - new function list_update written xs[i:=v] that updates the i-th
   793     list position. May also be iterated as in xs[i:=a,j:=b,...].
   794   - new function `upt' written [i..j(] which generates the list
   795     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   796     bound write [i..j], which is a shorthand for [i..j+1(].
   797   - new lexicographic orderings and corresponding wellfoundedness theorems.
   798 
   799 * HOL/Arith:
   800   - removed 'pred' (predecessor) function;
   801   - generalized some theorems about n-1;
   802   - many new laws about "div" and "mod";
   803   - new laws about greatest common divisors (see theory ex/Primes);
   804 
   805 * HOL/Relation: renamed the relational operator r^-1 "converse"
   806 instead of "inverse";
   807 
   808 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   809   of the multiset ordering;
   810 
   811 * directory HOL/Real: a construction of the reals using Dedekind cuts
   812   (not included by default);
   813 
   814 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   815 
   816 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   817   programs, i.e. different program variables may have different types.
   818 
   819 * calling (stac rew i) now fails if "rew" has no effect on the goal
   820   [previously, this check worked only if the rewrite rule was unconditional]
   821   Now rew can involve either definitions or equalities (either == or =).
   822 
   823 
   824 *** ZF ***
   825 
   826 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   827   only the theorems proved on ZF.ML;
   828 
   829 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   830   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   831   disjointness reasoning but breaking a few old proofs.
   832 
   833 * ZF/Update: new theory of function updates
   834     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   835   may also be iterated as in f(a:=b,c:=d,...);
   836 
   837 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   838 
   839 * calling (stac rew i) now fails if "rew" has no effect on the goal
   840   [previously, this check worked only if the rewrite rule was unconditional]
   841   Now rew can involve either definitions or equalities (either == or =).
   842 
   843 * case_tac provided for compatibility with HOL
   844     (like the old excluded_middle_tac, but with subgoals swapped)
   845 
   846 
   847 *** Internal programming interfaces ***
   848 
   849 * Pure: several new basic modules made available for general use, see
   850 also src/Pure/README;
   851 
   852 * improved the theory data mechanism to support encapsulation (data
   853 kind name replaced by private Object.kind, acting as authorization
   854 key); new type-safe user interface via functor TheoryDataFun; generic
   855 print_data function becomes basically useless;
   856 
   857 * removed global_names compatibility flag -- all theory declarations
   858 are qualified by default;
   859 
   860 * module Pure/Syntax now offers quote / antiquote translation
   861 functions (useful for Hoare logic etc. with implicit dependencies);
   862 see HOL/ex/Antiquote for an example use;
   863 
   864 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   865 cterm -> thm;
   866 
   867 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   868 subgoal;
   869 
   870 * Display.print_goals function moved to Locale.print_goals;
   871 
   872 * standard print function for goals supports current_goals_markers
   873 variable for marking begin of proof, end of proof, start of goal; the
   874 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   875 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   876 for example;
   877 
   878 
   879 
   880 New in Isabelle98 (January 1998)
   881 --------------------------------
   882 
   883 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   884 
   885 * changed lexical syntax of terms / types: dots made part of long
   886 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   887 
   888 * simpset (and claset) reference variable replaced by functions
   889 simpset / simpset_ref;
   890 
   891 * no longer supports theory aliases (via merge) and non-trivial
   892 implicit merge of thms' signatures;
   893 
   894 * most internal names of constants changed due to qualified names;
   895 
   896 * changed Pure/Sequence interface (see Pure/seq.ML);
   897 
   898 
   899 *** General Changes ***
   900 
   901 * hierachically structured name spaces (for consts, types, axms, thms
   902 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   903 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   904 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   905 long_names for fully qualified output names; NOTE: ML programs
   906 (special tactics, packages etc.) referring to internal names may have
   907 to be adapted to cope with fully qualified names; in case of severe
   908 backward campatibility problems try setting 'global_names' at compile
   909 time to have enrything declared within a flat name space; one may also
   910 fine tune name declarations in theories via the 'global' and 'local'
   911 section;
   912 
   913 * reimplemented the implicit simpset and claset using the new anytype
   914 data filed in signatures; references simpset:simpset ref etc. are
   915 replaced by functions simpset:unit->simpset and
   916 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   917 to patch your ML files accordingly;
   918 
   919 * HTML output now includes theory graph data for display with Java
   920 applet or isatool browser; data generated automatically via isatool
   921 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   922 
   923 * defs may now be conditional; improved rewrite_goals_tac to handle
   924 conditional equations;
   925 
   926 * defs now admits additional type arguments, using TYPE('a) syntax;
   927 
   928 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   929 creates a new theory node; implicit merge of thms' signatures is
   930 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   931 transfer:theory->thm->thm in (rare) cases;
   932 
   933 * improved handling of draft signatures / theories; draft thms (and
   934 ctyps, cterms) are automatically promoted to real ones;
   935 
   936 * slightly changed interfaces for oracles: admit many per theory, named
   937 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   938 
   939 * print_goals: optional output of const types (set show_consts and
   940 show_types);
   941 
   942 * improved output of warnings (###) and errors (***);
   943 
   944 * subgoal_tac displays a warning if the new subgoal has type variables;
   945 
   946 * removed old README and Makefiles;
   947 
   948 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   949 
   950 * removed obsolete init_pps and init_database;
   951 
   952 * deleted the obsolete tactical STATE, which was declared by
   953     fun STATE tacfun st = tacfun st st;
   954 
   955 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   956 (which abbreviates $HOME);
   957 
   958 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   959 use isatool fixseq to adapt your ML programs (this works for fully
   960 qualified references to the Sequence structure only!);
   961 
   962 * use_thy no longer requires writable current directory; it always
   963 reloads .ML *and* .thy file, if either one is out of date;
   964 
   965 
   966 *** Classical Reasoner ***
   967 
   968 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   969 tactics that use classical reasoning to simplify a subgoal without
   970 splitting it into several subgoals;
   971 
   972 * Safe_tac: like safe_tac but uses the default claset;
   973 
   974 
   975 *** Simplifier ***
   976 
   977 * added simplification meta rules:
   978     (asm_)(full_)simplify: simpset -> thm -> thm;
   979 
   980 * simplifier.ML no longer part of Pure -- has to be loaded by object
   981 logics (again);
   982 
   983 * added prems argument to simplification procedures;
   984 
   985 * HOL, FOL, ZF: added infix function `addsplits':
   986   instead of `<simpset> setloop (split_tac <thms>)'
   987   you can simply write `<simpset> addsplits <thms>'
   988 
   989 
   990 *** Syntax ***
   991 
   992 * TYPE('a) syntax for type reflection terms;
   993 
   994 * no longer handles consts with name "" -- declare as 'syntax' instead;
   995 
   996 * pretty printer: changed order of mixfix annotation preference (again!);
   997 
   998 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   999 
  1000 
  1001 *** HOL ***
  1002 
  1003 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1004   with `addloop' of the simplifier to faciliate case splitting in premises.
  1005 
  1006 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1007 
  1008 * HOL/Auth: new protocol proofs including some for the Internet
  1009   protocol TLS;
  1010 
  1011 * HOL/Map: new theory of `maps' a la VDM;
  1012 
  1013 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1014 cancelling out common nat summands from =, <, <= (in)equalities, or
  1015 differences; simplification procedures nat_cancel_factor for
  1016 cancelling common factor from =, <, <= (in)equalities over natural
  1017 sums; nat_cancel contains both kinds of procedures, it is installed by
  1018 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1019 
  1020 * HOL/simplifier: terms of the form
  1021   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1022   are rewritten to
  1023   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1024   and those of the form
  1025   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1026   are rewritten to
  1027   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1028 
  1029 * HOL/datatype
  1030   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1031 
  1032   P(t_case f1 ... fn x) =
  1033      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1034         ...
  1035        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1036      )
  1037 
  1038   and a theorem `split_t_case_asm' of the form
  1039 
  1040   P(t_case f1 ... fn x) =
  1041     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1042         ...
  1043        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1044      )
  1045   which can be added to a simpset via `addsplits'. The existing theorems
  1046   expand_list_case and expand_option_case have been renamed to
  1047   split_list_case and split_option_case.
  1048 
  1049 * HOL/Arithmetic:
  1050   - `pred n' is automatically converted to `n-1'.
  1051     Users are strongly encouraged not to use `pred' any longer,
  1052     because it will disappear altogether at some point.
  1053   - Users are strongly encouraged to write "0 < n" rather than
  1054     "n ~= 0". Theorems and proof tools have been modified towards this
  1055     `standard'.
  1056 
  1057 * HOL/Lists:
  1058   the function "set_of_list" has been renamed "set" (and its theorems too);
  1059   the function "nth" now takes its arguments in the reverse order and
  1060   has acquired the infix notation "!" as in "xs!n".
  1061 
  1062 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1063 
  1064 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1065   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1066 
  1067 * HOL/record: extensible records with schematic structural subtyping
  1068 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1069 still lacks various theorems and concrete record syntax;
  1070 
  1071 
  1072 *** HOLCF ***
  1073 
  1074 * removed "axioms" and "generated by" sections;
  1075 
  1076 * replaced "ops" section by extended "consts" section, which is capable of
  1077   handling the continuous function space "->" directly;
  1078 
  1079 * domain package:
  1080   . proves theorems immediately and stores them in the theory,
  1081   . creates hierachical name space,
  1082   . now uses normal mixfix annotations (instead of cinfix...),
  1083   . minor changes to some names and values (for consistency),
  1084   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1085   . separator between mutual domain defs: changed "," to "and",
  1086   . improved handling of sort constraints;  now they have to
  1087     appear on the left-hand side of the equations only;
  1088 
  1089 * fixed LAM <x,y,zs>.b syntax;
  1090 
  1091 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1092 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1093 
  1094 
  1095 *** FOL and ZF ***
  1096 
  1097 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1098   with `addloop' of the simplifier to faciliate case splitting in premises.
  1099 
  1100 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1101 in HOL, they strip ALL and --> from proved theorems;
  1102 
  1103 
  1104 
  1105 New in Isabelle94-8 (May 1997)
  1106 ------------------------------
  1107 
  1108 *** General Changes ***
  1109 
  1110 * new utilities to build / run / maintain Isabelle etc. (in parts
  1111 still somewhat experimental); old Makefiles etc. still functional;
  1112 
  1113 * new 'Isabelle System Manual';
  1114 
  1115 * INSTALL text, together with ./configure and ./build scripts;
  1116 
  1117 * reimplemented type inference for greater efficiency, better error
  1118 messages and clean internal interface;
  1119 
  1120 * prlim command for dealing with lots of subgoals (an easier way of
  1121 setting goals_limit);
  1122 
  1123 
  1124 *** Syntax ***
  1125 
  1126 * supports alternative (named) syntax tables (parser and pretty
  1127 printer); internal interface is provided by add_modesyntax(_i);
  1128 
  1129 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1130 be used in conjunction with the Isabelle symbol font; uses the
  1131 "symbols" syntax table;
  1132 
  1133 * added token_translation interface (may translate name tokens in
  1134 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1135 the current print_mode); IMPORTANT: user print translation functions
  1136 are responsible for marking newly introduced bounds
  1137 (Syntax.mark_boundT);
  1138 
  1139 * token translations for modes "xterm" and "xterm_color" that display
  1140 names in bold, underline etc. or colors (which requires a color
  1141 version of xterm);
  1142 
  1143 * infixes may now be declared with names independent of their syntax;
  1144 
  1145 * added typed_print_translation (like print_translation, but may
  1146 access type of constant);
  1147 
  1148 
  1149 *** Classical Reasoner ***
  1150 
  1151 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1152 some limitations.  Blast_tac...
  1153   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1154   + ignores elimination rules that don't have the correct format
  1155         (the conclusion MUST be a formula variable)
  1156   + ignores types, which can make HOL proofs fail
  1157   + rules must not require higher-order unification, e.g. apply_type in ZF
  1158     [message "Function Var's argument not a bound variable" relates to this]
  1159   + its proof strategy is more general but can actually be slower
  1160 
  1161 * substitution with equality assumptions no longer permutes other
  1162 assumptions;
  1163 
  1164 * minor changes in semantics of addafter (now called addaltern); renamed
  1165 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1166 (and access functions for it);
  1167 
  1168 * improved combination of classical reasoner and simplifier:
  1169   + functions for handling clasimpsets
  1170   + improvement of addss: now the simplifier is called _after_ the
  1171     safe steps.
  1172   + safe variant of addss called addSss: uses safe simplifications
  1173     _during_ the safe steps. It is more complete as it allows multiple
  1174     instantiations of unknowns (e.g. with slow_tac).
  1175 
  1176 *** Simplifier ***
  1177 
  1178 * added interface for simplification procedures (functions that
  1179 produce *proven* rewrite rules on the fly, depending on current
  1180 redex);
  1181 
  1182 * ordering on terms as parameter (used for ordered rewriting);
  1183 
  1184 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1185 
  1186 * the solver is now split into a safe and an unsafe part.
  1187 This should be invisible for the normal user, except that the
  1188 functions setsolver and addsolver have been renamed to setSolver and
  1189 addSolver; added safe_asm_full_simp_tac;
  1190 
  1191 
  1192 *** HOL ***
  1193 
  1194 * a generic induction tactic `induct_tac' which works for all datatypes and
  1195 also for type `nat';
  1196 
  1197 * a generic case distinction tactic `exhaust_tac' which works for all
  1198 datatypes and also for type `nat';
  1199 
  1200 * each datatype comes with a function `size';
  1201 
  1202 * patterns in case expressions allow tuple patterns as arguments to
  1203 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1204 
  1205 * primrec now also works with type nat;
  1206 
  1207 * recdef: a new declaration form, allows general recursive functions to be
  1208 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1209 
  1210 * the constant for negation has been renamed from "not" to "Not" to
  1211 harmonize with FOL, ZF, LK, etc.;
  1212 
  1213 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1214 infinite lists;
  1215 
  1216 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1217 
  1218 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1219 problems in commutative rings, using axiomatic type classes for + and *;
  1220 
  1221 * more examples in HOL/MiniML and HOL/Auth;
  1222 
  1223 * more default rewrite rules for quantifiers, union/intersection;
  1224 
  1225 * a new constant `arbitrary == @x.False';
  1226 
  1227 * HOLCF/IOA replaces old HOL/IOA;
  1228 
  1229 * HOLCF changes: derived all rules and arities
  1230   + axiomatic type classes instead of classes
  1231   + typedef instead of faking type definitions
  1232   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1233   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1234   + eliminated the types void, one, tr
  1235   + use unit lift and bool lift (with translations) instead of one and tr
  1236   + eliminated blift from Lift3.thy (use Def instead of blift)
  1237   all eliminated rules are derived as theorems --> no visible changes ;
  1238 
  1239 
  1240 *** ZF ***
  1241 
  1242 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1243 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1244 as ZF_cs addSIs [equalityI];
  1245 
  1246 
  1247 
  1248 New in Isabelle94-7 (November 96)
  1249 ---------------------------------
  1250 
  1251 * allowing negative levels (as offsets) in prlev and choplev;
  1252 
  1253 * super-linear speedup for large simplifications;
  1254 
  1255 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1256 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1257 FAIL); can suppress it using the command Delsimps (ex_simps @
  1258 all_simps); De Morgan laws are also now included, by default;
  1259 
  1260 * improved printing of ==>  :  ~:
  1261 
  1262 * new object-logic "Sequents" adds linear logic, while replacing LK
  1263 and Modal (thanks to Sara Kalvala);
  1264 
  1265 * HOL/Auth: correctness proofs for authentication protocols;
  1266 
  1267 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1268 examples on HOL/Auth);
  1269 
  1270 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1271 the rewriter and classical reasoner simultaneously;
  1272 
  1273 * function uresult no longer returns theorems in "standard" format;
  1274 regain previous version by: val uresult = standard o uresult;
  1275 
  1276 
  1277 
  1278 New in Isabelle94-6
  1279 -------------------
  1280 
  1281 * oracles -- these establish an interface between Isabelle and trusted
  1282 external reasoners, which may deliver results as theorems;
  1283 
  1284 * proof objects (in particular record all uses of oracles);
  1285 
  1286 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1287 
  1288 * "constdefs" section in theory files;
  1289 
  1290 * "primrec" section (HOL) no longer requires names;
  1291 
  1292 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1293 
  1294 
  1295 
  1296 New in Isabelle94-5
  1297 -------------------
  1298 
  1299 * reduced space requirements;
  1300 
  1301 * automatic HTML generation from theories;
  1302 
  1303 * theory files no longer require "..." (quotes) around most types;
  1304 
  1305 * new examples, including two proofs of the Church-Rosser theorem;
  1306 
  1307 * non-curried (1994) version of HOL is no longer distributed;
  1308 
  1309 
  1310 
  1311 New in Isabelle94-4
  1312 -------------------
  1313 
  1314 * greatly reduced space requirements;
  1315 
  1316 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1317 
  1318 * searchable theorem database (see the section "Retrieving theorems" on
  1319 page 8 of the Reference Manual);
  1320 
  1321 * new examples, including Grabczewski's monumental case study of the
  1322 Axiom of Choice;
  1323 
  1324 * The previous version of HOL renamed to Old_HOL;
  1325 
  1326 * The new version of HOL (previously called CHOL) uses a curried syntax
  1327 for functions.  Application looks like f a b instead of f(a,b);
  1328 
  1329 * Mutually recursive inductive definitions finally work in HOL;
  1330 
  1331 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1332 translates to the operator "split";
  1333 
  1334 
  1335 
  1336 New in Isabelle94-3
  1337 -------------------
  1338 
  1339 * new infix operator, addss, allowing the classical reasoner to
  1340 perform simplification at each step of its search.  Example:
  1341         fast_tac (cs addss ss)
  1342 
  1343 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1344 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1345 look like (a,b) instead of <a,b>;
  1346 
  1347 * PLEASE NOTE: CHOL will eventually replace HOL!
  1348 
  1349 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1350 It translates to the operator "split".  A new theory of integers is available;
  1351 
  1352 * In ZF, integer numerals now denote two's-complement binary integers.
  1353 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1354 
  1355 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1356 of the Axiom of Choice;
  1357 
  1358 
  1359 
  1360 New in Isabelle94-2
  1361 -------------------
  1362 
  1363 * Significantly faster resolution;
  1364 
  1365 * the different sections in a .thy file can now be mixed and repeated
  1366 freely;
  1367 
  1368 * Database of theorems for FOL, HOL and ZF.  New
  1369 commands including qed, qed_goal and bind_thm store theorems in the database.
  1370 
  1371 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1372 a given theory (thms_of), or find out what theory a theorem was proved in
  1373 (theory_of_thm);
  1374 
  1375 * Bugs fixed in the inductive definition and datatype packages;
  1376 
  1377 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1378 and HOL_dup_cs obsolete;
  1379 
  1380 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1381 have been removed;
  1382 
  1383 * Simpler definition of function space in ZF;
  1384 
  1385 * new results about cardinal and ordinal arithmetic in ZF;
  1386 
  1387 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1388 types;
  1389 
  1390 
  1391 $Id$