NEWS
author paulson
Thu Jun 29 12:14:04 2000 +0200 (2000-06-29)
changeset 9185 30d46270a427
parent 9085 5ce73f3cadff
child 9198 0ab3c81e9425
permissions -rw-r--r--
weak elimination rules
     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    25 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;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 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
    44   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
    45 use instead the strong form,
    46   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
    47 In HOL, FOR and ZF the function cla_make_elim will create such rules
    48 from destruct-rules;
    49 
    50 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
    51 timing flag supersedes proof_timing and Toplevel.trace;
    52 
    53 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    54 
    55 * LaTeX: several improvements of isabelle.sty;
    56 
    57 
    58 *** Document preparation ***
    59 
    60 * isatool mkdir provides easy setup of Isabelle session directories,
    61 including proper document sources;
    62 
    63 * generated LaTeX sources are now deleted after successful run
    64 (isatool document -c); may retain a copy somewhere else via -D option
    65 of isatool usedir;
    66 
    67 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    68 style files, achieving self-contained LaTeX sources;
    69 
    70 * old-style theories now produce (crude) LaTeX output as well;
    71 
    72 * browser info session directories are now self-contained (may be put
    73 on WWW server seperately);
    74 
    75 
    76 *** Isar ***
    77 
    78 * Pure: local results and corresponding term bindings are now subject
    79 to Hindley-Milner polymorphism (similar to ML); this accommodates
    80 incremental type-inference nicely;
    81 
    82 * Pure: new 'obtain' language element supports generalized existence
    83 reasoning;
    84 
    85 * Pure: new calculational elements 'moreover' and 'ultimately' support
    86 plain accumulation of results, without applying any rules yet;
    87 
    88 * Pure: scalable support for case-analysis type proofs: new 'case'
    89 language element refers to local contexts symbolically, as produced by
    90 certain proof methods; internally, case names are attached to theorems
    91 as "tags";
    92 
    93 * Pure: changed syntax of local blocks from {{ }} to { };
    94 
    95 * Pure: syntax of sorts made inner, i.e. have to write "{a, b, c}"
    96 instead of {a, b, c};
    97 
    98 * Pure now provides its own version of intro/elim/dest attributes;
    99 useful for building new logics, but beware of confusion with the
   100 Provers/classical ones;
   101 
   102 * Pure: the local context of (non-atomic) goals is provided via case
   103 name 'antecedent';
   104 
   105 * Pure: removed obsolete 'transfer' attribute (transfer of thms to the
   106 current context is now done automatically);
   107 
   108 * Provers: splitter support (via 'split' attribute and 'simp' method
   109 modifier); 'simp' method: 'only:' modifier removes loopers as well
   110 (including splits);
   111 
   112 * HOL: new proof method 'cases' and improved version of 'induct' now
   113 support named cases; major packages (inductive, datatype, primrec,
   114 recdef) support case names and properly name parameters;
   115 
   116 * HOL: removed 'case_split' thm binding, should use 'cases' proof
   117 method anyway;
   118 
   119 * names of theorems etc. may be natural numbers as well;
   120 
   121 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
   122 
   123 * 'pr' command: optional goals_limit argument; no longer prints theory
   124 contexts, but only proof states;
   125 
   126 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   127 additional print modes to be specified; e.g. "pr(latex)" will print
   128 proof state according to the Isabelle LaTeX style;
   129 
   130 * improved support for emulating tactic scripts, including proof
   131 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
   132 'induct_tac' (for HOL datatypes);
   133 
   134 * simplified (more robust) goal selection of proof methods: 1st goal,
   135 all goals, or explicit goal specifier (tactic emulation); thus 'proof
   136 method scripts' have to be in depth-first order;
   137 
   138 * tuned 'let' syntax: replace 'as' keyword by 'and';
   139 
   140 * theory command 'hide' removes declarations from class/type/const
   141 name spaces;
   142 
   143 
   144 *** HOL ***
   145 
   146 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog
   147 
   148 * HOL/Algebra: new theory of rings and univariate polynomials, by
   149 Clemens Ballarin;
   150 
   151 * HOL/record: fixed select-update simplification procedure to handle
   152 extended records as well; admit "r" as field name;
   153 
   154 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
   155 Arithmetic, by Thomas M Rasmussen;
   156 
   157 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
   158 basically a generalized version of de-Bruijn representation; very
   159 useful in avoiding lifting all operations;
   160 
   161 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   162 
   163 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   164 other numeric types and also as the identity of groups, rings, etc.;
   165 
   166 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   167 Types nat and int belong to this axclass;
   168 
   169 * greatly improved simplification involving numerals of type nat, int, real:
   170    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   171    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   172   two terms #m*u and #n*u are replaced by #(m+n)*u
   173     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   174   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   175     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   176 
   177 * HOL: new version of "case_tac" subsumes both boolean case split and
   178 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   179 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   180 
   181 * HOL: simplification no longer dives into case-expressions: only the
   182 selector expression is simplified, but not the remaining arms. To
   183 enable full simplification of case-expressions for datatype t, you
   184 need to remove t.weak_case_cong from the simpset, either permanently
   185 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   186 
   187 * HOL/recdef: the recursion equations generated by 'recdef' for
   188 function 'f' are now called f.simps instead of f.rules; if all
   189 termination conditions are proved automatically, these simplification
   190 rules are added to the simpset, as in primrec; rules may be named
   191 individually as well, resulting in a separate list of theorems for
   192 each equation;
   193 
   194 * HOL: new (overloaded) notation for the set of elements below/above some
   195 element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   196 
   197 * HOL: theorems impI, allI, ballI bound as "strip";
   198 
   199 * theory Sexp now in HOL/Induct examples (used to be part of main HOL,
   200 but was unused);
   201 
   202 * fewer consts declared as global (e.g. have to refer to "Lfp.lfp"
   203 instead of "lfp" internally; affects ML packages only);
   204 
   205 
   206 *** General ***
   207 
   208 * improved name spaces: ambiguous output is qualified; support for
   209 hiding of names;
   210 
   211 * compression of ML heaps images may now be controlled via -c option
   212 of isabelle and isatool usedir (currently only observed by Poly/ML);
   213 
   214 * provide TAGS file for Isabelle sources;
   215 
   216 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   217 timing flag supersedes proof_timing and Toplevel.trace;
   218 
   219 * ML: new combinators |>> and |>>> for incremental transformations
   220 with secondary results (e.g. certain theory extensions):
   221 
   222 
   223 
   224 New in Isabelle99 (October 1999)
   225 --------------------------------
   226 
   227 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   228 
   229 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   230 are no longer simplified.  (This allows the simplifier to unfold recursive
   231 functional programs.)  To restore the old behaviour, declare
   232 
   233     Delcongs [if_weak_cong];
   234 
   235 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   236 complement;
   237 
   238 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   239 
   240 * HOL/datatype: mutual_induct_tac no longer exists --
   241   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   242 
   243 * HOL/typedef: fixed type inference for representing set; type
   244 arguments now have to occur explicitly on the rhs as type constraints;
   245 
   246 * ZF: The con_defs part of an inductive definition may no longer refer
   247 to constants declared in the same theory;
   248 
   249 * HOL, ZF: the function mk_cases, generated by the inductive
   250 definition package, has lost an argument.  To simplify its result, it
   251 uses the default simpset instead of a supplied list of theorems.
   252 
   253 * HOL/List: the constructors of type list are now Nil and Cons;
   254 
   255 * Simplifier: the type of the infix ML functions
   256         setSSolver addSSolver setSolver addSolver
   257 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   258 for packaging solvers. A solver is created via
   259         mk_solver: string -> (thm list -> int -> tactic) -> solver
   260 where the string argument is only a comment.
   261 
   262 
   263 *** Proof tools ***
   264 
   265 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   266 decision procedure for linear arithmetic. Currently it is used for
   267 types `nat', `int', and `real' in HOL (see below); it can, should and
   268 will be instantiated for other types and logics as well.
   269 
   270 * The simplifier now accepts rewrite rules with flexible heads, eg
   271      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   272   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   273   matching.
   274 
   275 
   276 *** General ***
   277 
   278 * New Isabelle/Isar subsystem provides an alternative to traditional
   279 tactical theorem proving; together with the ProofGeneral/isar user
   280 interface it offers an interactive environment for developing human
   281 readable proof documents (Isar == Intelligible semi-automated
   282 reasoning); for further information see isatool doc isar-ref,
   283 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   284 
   285 * improved presentation of theories: better HTML markup (including
   286 colors), graph views in several sizes; isatool usedir now provides a
   287 proper interface for user theories (via -P option); actual document
   288 preparation based on (PDF)LaTeX is available as well (for new-style
   289 theories only); see isatool doc system for more information;
   290 
   291 * native support for Proof General, both for classic Isabelle and
   292 Isabelle/Isar;
   293 
   294 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   295 using the graph browser tool;
   296 
   297 * Isabelle manuals now also available as PDF;
   298 
   299 * theory loader rewritten from scratch (may not be fully
   300 bug-compatible); old loadpath variable has been replaced by show_path,
   301 add_path, del_path, reset_path functions; new operations such as
   302 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   303 isatool doc ref);
   304 
   305 * improved isatool install: option -k creates KDE application icon,
   306 option -p DIR installs standalone binaries;
   307 
   308 * added ML_PLATFORM setting (useful for cross-platform installations);
   309 more robust handling of platform specific ML images for SML/NJ;
   310 
   311 * the settings environment is now statically scoped, i.e. it is never
   312 created again in sub-processes invoked from isabelle, isatool, or
   313 Isabelle;
   314 
   315 * path element specification '~~' refers to '$ISABELLE_HOME';
   316 
   317 * in locales, the "assumes" and "defines" parts may be omitted if
   318 empty;
   319 
   320 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   321 long arrows);
   322 
   323 * new print_mode "HTML";
   324 
   325 * new flag show_tags controls display of tags of theorems (which are
   326 basically just comments that may be attached by some tools);
   327 
   328 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   329 mode and goal output format:
   330 
   331 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   332 244c244
   333 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   334 ---
   335 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   336 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   337 181c181
   338 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   339 ---
   340 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   341 
   342 * function bind_thms stores lists of theorems (cf. bind_thm);
   343 
   344 * new shorthand tactics ftac, eatac, datac, fatac;
   345 
   346 * qed (and friends) now accept "" as result name; in that case the
   347 theorem is not stored, but proper checks and presentation of the
   348 result still apply;
   349 
   350 * theorem database now also indexes constants "Trueprop", "all",
   351 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   352 
   353 
   354 *** HOL ***
   355 
   356 ** HOL arithmetic **
   357 
   358 * There are now decision procedures for linear arithmetic over nat and
   359 int:
   360 
   361 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   362 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   363 are treated as atomic; subformulae not involving type `nat' or `int'
   364 are ignored; quantified subformulae are ignored unless they are
   365 positive universal or negative existential. The tactic has to be
   366 invoked by hand and can be a little bit slow. In particular, the
   367 running time is exponential in the number of occurrences of `min' and
   368 `max', and `-' on `nat'.
   369 
   370 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   371 (negated) (in)equalities among the premises and the conclusion into
   372 account (i.e. no compound formulae) and does not know about `min' and
   373 `max', and `-' on `nat'. It is fast and is used automatically by the
   374 simplifier.
   375 
   376 NB: At the moment, these decision procedures do not cope with mixed
   377 nat/int formulae where the two parts interact, such as `m < n ==>
   378 int(m) < int(n)'.
   379 
   380 * HOL/Numeral provides a generic theory of numerals (encoded
   381 efficiently as bit strings); setup for types nat/int/real is in place;
   382 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   383 int, existing theories and proof scripts may require a few additional
   384 type constraints;
   385 
   386 * integer division and remainder can now be performed on constant
   387 arguments;
   388 
   389 * many properties of integer multiplication, division and remainder
   390 are now available;
   391 
   392 * An interface to the Stanford Validity Checker (SVC) is available through the
   393 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   394 are proved automatically.  SVC must be installed separately, and its results
   395 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   396 invocation of the underlying oracle).  For SVC see
   397   http://verify.stanford.edu/SVC
   398 
   399 * IsaMakefile: the HOL-Real target now builds an actual image;
   400 
   401 
   402 ** HOL misc **
   403 
   404 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   405 (in Isabelle/Isar) -- by Gertrud Bauer;
   406 
   407 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   408 analysis for assembly languages with subtypes;
   409 
   410 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   411 -- avoids syntactic ambiguities and treats state, transition, and
   412 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   413 changed syntax and (many) tactics;
   414 
   415 * HOL/inductive: Now also handles more general introduction rules such
   416   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   417   theorems are now maintained within the theory (maintained via the
   418   "mono" attribute);
   419 
   420 * HOL/datatype: Now also handles arbitrarily branching datatypes
   421   (using function types) such as
   422 
   423   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   424 
   425 * HOL/record: record_simproc (part of the default simpset) takes care
   426 of selectors applied to updated records; record_split_tac is no longer
   427 part of the default claset; update_defs may now be removed from the
   428 simpset in many cases; COMPATIBILITY: old behavior achieved by
   429 
   430   claset_ref () := claset() addSWrapper record_split_wrapper;
   431   Delsimprocs [record_simproc]
   432 
   433 * HOL/typedef: fixed type inference for representing set; type
   434 arguments now have to occur explicitly on the rhs as type constraints;
   435 
   436 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   437 names rather than an ML expression;
   438 
   439 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   440 supplied later.  Program schemes can be defined, such as
   441     "While B C s = (if B s then While B C (C s) else s)"
   442 where the well-founded relation can be chosen after B and C have been given.
   443 
   444 * HOL/List: the constructors of type list are now Nil and Cons;
   445 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   446 course, ML tools referring to List.list.op # etc. have to be adapted;
   447 
   448 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   449 disabled by default; run isabelle with option -m HOL to get back to
   450 the original Gordon/HOL-style output;
   451 
   452 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   453 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   454 
   455 * HOL basic syntax simplified (more orthogonal): all variants of
   456 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   457 Eps operator is provided as well: "SOME x. P[x]";
   458 
   459 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   460 
   461 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   462 thus available for user theories;
   463 
   464 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   465 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   466 time;
   467 
   468 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   469 several times and then mp;
   470 
   471 
   472 *** LK ***
   473 
   474 * the notation <<...>> is now available as a notation for sequences of
   475 formulas;
   476 
   477 * the simplifier is now installed
   478 
   479 * the axiom system has been generalized (thanks to Soren Heilmann)
   480 
   481 * the classical reasoner now has a default rule database
   482 
   483 
   484 *** ZF ***
   485 
   486 * new primrec section allows primitive recursive functions to be given
   487 directly (as in HOL) over datatypes and the natural numbers;
   488 
   489 * new tactics induct_tac and exhaust_tac for induction (or case
   490 analysis) over datatypes and the natural numbers;
   491 
   492 * the datatype declaration of type T now defines the recursor T_rec;
   493 
   494 * simplification automatically does freeness reasoning for datatype
   495 constructors;
   496 
   497 * automatic type-inference, with AddTCs command to insert new
   498 type-checking rules;
   499 
   500 * datatype introduction rules are now added as Safe Introduction rules
   501 to the claset;
   502 
   503 * the syntax "if P then x else y" is now available in addition to
   504 if(P,x,y);
   505 
   506 
   507 *** Internal programming interfaces ***
   508 
   509 * tuned simplifier trace output; new flag debug_simp;
   510 
   511 * structures Vartab / Termtab (instances of TableFun) offer efficient
   512 tables indexed by indexname_ord / term_ord (compatible with aconv);
   513 
   514 * AxClass.axclass_tac lost the theory argument;
   515 
   516 * tuned current_goals_markers semantics: begin / end goal avoids
   517 printing empty lines;
   518 
   519 * removed prs and prs_fn hook, which was broken because it did not
   520 include \n in its semantics, forcing writeln to add one
   521 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   522 string -> unit if you really want to output text without newline;
   523 
   524 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   525 plain output, interface builders may have to enable 'isabelle_font'
   526 mode to get Isabelle font glyphs as before;
   527 
   528 * refined token_translation interface; INCOMPATIBILITY: output length
   529 now of type real instead of int;
   530 
   531 * theory loader actions may be traced via new ThyInfo.add_hook
   532 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   533 your own database of information attached to *whole* theories -- as
   534 opposed to intra-theory data slots offered via TheoryDataFun;
   535 
   536 * proper handling of dangling sort hypotheses (at last!);
   537 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   538 extra sort hypotheses that can be witnessed from the type signature;
   539 the force_strip_shyps flag is gone, any remaining shyps are simply
   540 left in the theorem (with a warning issued by strip_shyps_warning);
   541 
   542 
   543 
   544 New in Isabelle98-1 (October 1998)
   545 ----------------------------------
   546 
   547 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   548 
   549 * several changes of automated proof tools;
   550 
   551 * HOL: major changes to the inductive and datatype packages, including
   552 some minor incompatibilities of theory syntax;
   553 
   554 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   555 called `inj_on';
   556 
   557 * HOL: removed duplicate thms in Arith:
   558   less_imp_add_less  should be replaced by  trans_less_add1
   559   le_imp_add_le      should be replaced by  trans_le_add1
   560 
   561 * HOL: unary minus is now overloaded (new type constraints may be
   562 required);
   563 
   564 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   565 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   566 now taken as an integer constant.
   567 
   568 * Pure: ML function 'theory_of' renamed to 'theory';
   569 
   570 
   571 *** Proof tools ***
   572 
   573 * Simplifier:
   574   1. Asm_full_simp_tac is now more aggressive.
   575      1. It will sometimes reorient premises if that increases their power to
   576         simplify.
   577      2. It does no longer proceed strictly from left to right but may also
   578         rotate premises to achieve further simplification.
   579      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   580      old Asm_full_simp_tac in that it does not rotate premises.
   581   2. The simplifier now knows a little bit about nat-arithmetic.
   582 
   583 * Classical reasoner: wrapper mechanism for the classical reasoner now
   584 allows for selected deletion of wrappers, by introduction of names for
   585 wrapper functionals.  This implies that addbefore, addSbefore,
   586 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   587 and that adding two tactics with the same name overwrites the first
   588 one (emitting a warning).
   589   type wrapper = (int -> tactic) -> (int -> tactic)
   590   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   591   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   592   delWrapper, delSWrapper: claset *  string            -> claset
   593   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   594 
   595 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   596 semantics; addbefore now affects only the unsafe part of step_tac
   597 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   598 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   599 by Force_tac;
   600 
   601 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   602 compWrapper; added safe wrapper (and access functions for it);
   603 
   604 * HOL/split_all_tac is now much faster and fails if there is nothing
   605 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   606 and the names of the automatically generated variables have changed.
   607 split_all_tac has moved within claset() from unsafe wrappers to safe
   608 wrappers, which means that !!-bound variables are split much more
   609 aggressively, and safe_tac and clarify_tac now split such variables.
   610 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   611 Note: the same holds for record_split_tac, which does the job of
   612 split_all_tac for record fields.
   613 
   614 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   615 permanently to the default simpset using Addsplits just like
   616 Addsimps. They can be removed via Delsplits just like
   617 Delsimps. Lower-case versions are also available.
   618 
   619 * HOL/Simplifier: The rule split_if is now part of the default
   620 simpset. This means that the simplifier will eliminate all occurrences
   621 of if-then-else in the conclusion of a goal. To prevent this, you can
   622 either remove split_if completely from the default simpset by
   623 `Delsplits [split_if]' or remove it in a specific call of the
   624 simplifier using `... delsplits [split_if]'.  You can also add/delete
   625 other case splitting rules to/from the default simpset: every datatype
   626 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   627 t is the name of the datatype).
   628 
   629 * Classical reasoner / Simplifier combination: new force_tac (and
   630 derivatives Force_tac, force) combines rewriting and classical
   631 reasoning (and whatever other tools) similarly to auto_tac, but is
   632 aimed to solve the given subgoal completely.
   633 
   634 
   635 *** General ***
   636 
   637 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   638 and `goalw': the theory is no longer needed as an explicit argument -
   639 the current theory context is used; assumptions are no longer returned
   640 at the ML-level unless one of them starts with ==> or !!; it is
   641 recommended to convert to these new commands using isatool fixgoal
   642 (backup your sources first!);
   643 
   644 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   645 the current theory context, and 'theory' to lookup stored theories;
   646 
   647 * new theory section 'locale' for declaring constants, assumptions and
   648 definitions that have local scope;
   649 
   650 * new theory section 'nonterminals' for purely syntactic types;
   651 
   652 * new theory section 'setup' for generic ML setup functions
   653 (e.g. package initialization);
   654 
   655 * the distribution now includes Isabelle icons: see
   656 lib/logo/isabelle-{small,tiny}.xpm;
   657 
   658 * isatool install - install binaries with absolute references to
   659 ISABELLE_HOME/bin;
   660 
   661 * isatool logo -- create instances of the Isabelle logo (as EPS);
   662 
   663 * print mode 'emacs' reserved for Isamode;
   664 
   665 * support multiple print (ast) translations per constant name;
   666 
   667 * theorems involving oracles are now printed with a suffixed [!];
   668 
   669 
   670 *** HOL ***
   671 
   672 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   673 
   674 * HOL/inductive package reorganized and improved: now supports mutual
   675 definitions such as
   676 
   677   inductive EVEN ODD
   678     intrs
   679       null "0 : EVEN"
   680       oddI "n : EVEN ==> Suc n : ODD"
   681       evenI "n : ODD ==> Suc n : EVEN"
   682 
   683 new theorem list "elims" contains an elimination rule for each of the
   684 recursive sets; inductive definitions now handle disjunctive premises
   685 correctly (also ZF);
   686 
   687 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   688 "mutual_induct" no longer exists - the induction rule is always
   689 contained in "induct";
   690 
   691 
   692 * HOL/datatype package re-implemented and greatly improved: now
   693 supports mutually recursive datatypes such as
   694 
   695   datatype
   696     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   697             | SUM ('a aexp) ('a aexp)
   698             | DIFF ('a aexp) ('a aexp)
   699             | NUM 'a
   700   and
   701     'a bexp = LESS ('a aexp) ('a aexp)
   702             | AND ('a bexp) ('a bexp)
   703             | OR ('a bexp) ('a bexp)
   704 
   705 as well as indirectly recursive datatypes such as
   706 
   707   datatype
   708     ('a, 'b) term = Var 'a
   709                   | App 'b ((('a, 'b) term) list)
   710 
   711 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   712 induction on mutually / indirectly recursive datatypes.
   713 
   714 Primrec equations are now stored in theory and can be accessed via
   715 <function_name>.simps.
   716 
   717 INCOMPATIBILITIES:
   718 
   719   - Theories using datatypes must now have theory Datatype as an
   720     ancestor.
   721   - The specific <typename>.induct_tac no longer exists - use the
   722     generic induct_tac instead.
   723   - natE has been renamed to nat.exhaust - use exhaust_tac
   724     instead of res_inst_tac ... natE. Note that the variable
   725     names in nat.exhaust differ from the names in natE, this
   726     may cause some "fragile" proofs to fail.
   727   - The theorems split_<typename>_case and split_<typename>_case_asm
   728     have been renamed to <typename>.split and <typename>.split_asm.
   729   - Since default sorts of type variables are now handled correctly,
   730     some datatype definitions may have to be annotated with explicit
   731     sort constraints.
   732   - Primrec definitions no longer require function name and type
   733     of recursive argument.
   734 
   735 Consider using isatool fixdatatype to adapt your theories and proof
   736 scripts to the new package (backup your sources first!).
   737 
   738 
   739 * HOL/record package: considerably improved implementation; now
   740 includes concrete syntax for record types, terms, updates; theorems
   741 for surjective pairing and splitting !!-bound record variables; proof
   742 support is as follows:
   743 
   744   1) standard conversions (selectors or updates applied to record
   745 constructor terms) are part of the standard simpset;
   746 
   747   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   748 made part of standard simpset and claset via addIffs;
   749 
   750   3) a tactic for record field splitting (record_split_tac) is part of
   751 the standard claset (addSWrapper);
   752 
   753 To get a better idea about these rules you may retrieve them via
   754 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   755 the name of your record type.
   756 
   757 The split tactic 3) conceptually simplifies by the following rule:
   758 
   759   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   760 
   761 Thus any record variable that is bound by meta-all will automatically
   762 blow up into some record constructor term, consequently the
   763 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   764 solve record problems automatically.
   765 
   766 
   767 * reorganized the main HOL image: HOL/Integ and String loaded by
   768 default; theory Main includes everything;
   769 
   770 * automatic simplification of integer sums and comparisons, using cancellation;
   771 
   772 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   773 
   774 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   775 
   776 * many new identities for unions, intersections, set difference, etc.;
   777 
   778 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   779 called split_if, split_split, split_sum_case and split_nat_case (to go
   780 with add/delsplits);
   781 
   782 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   783 (?x::unit) = (); this is made part of the default simpset, which COULD
   784 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   785 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   786 unit_abs_eta_conv is added in order to counter the effect of
   787 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   788 %u.f();
   789 
   790 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   791 makes more sense);
   792 
   793 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   794   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   795   disjointness reasoning but breaking a few old proofs.
   796 
   797 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   798 to 'converse' from 'inverse' (for compatibility with ZF and some
   799 literature);
   800 
   801 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   802 the well-founded relation;
   803 
   804 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   805     Compl A.  The "Compl" syntax remains available as input syntax for this
   806     release ONLY.
   807 
   808 * HOL/Update: new theory of function updates:
   809     f(a:=b) == %x. if x=a then b else f x
   810 may also be iterated as in f(a:=b,c:=d,...);
   811 
   812 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   813 
   814 * HOL/List:
   815   - new function list_update written xs[i:=v] that updates the i-th
   816     list position. May also be iterated as in xs[i:=a,j:=b,...].
   817   - new function `upt' written [i..j(] which generates the list
   818     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   819     bound write [i..j], which is a shorthand for [i..j+1(].
   820   - new lexicographic orderings and corresponding wellfoundedness theorems.
   821 
   822 * HOL/Arith:
   823   - removed 'pred' (predecessor) function;
   824   - generalized some theorems about n-1;
   825   - many new laws about "div" and "mod";
   826   - new laws about greatest common divisors (see theory ex/Primes);
   827 
   828 * HOL/Relation: renamed the relational operator r^-1 "converse"
   829 instead of "inverse";
   830 
   831 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   832   of the multiset ordering;
   833 
   834 * directory HOL/Real: a construction of the reals using Dedekind cuts
   835   (not included by default);
   836 
   837 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   838 
   839 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   840   programs, i.e. different program variables may have different types.
   841 
   842 * calling (stac rew i) now fails if "rew" has no effect on the goal
   843   [previously, this check worked only if the rewrite rule was unconditional]
   844   Now rew can involve either definitions or equalities (either == or =).
   845 
   846 
   847 *** ZF ***
   848 
   849 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   850   only the theorems proved on ZF.ML;
   851 
   852 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   853   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   854   disjointness reasoning but breaking a few old proofs.
   855 
   856 * ZF/Update: new theory of function updates
   857     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   858   may also be iterated as in f(a:=b,c:=d,...);
   859 
   860 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   861 
   862 * calling (stac rew i) now fails if "rew" has no effect on the goal
   863   [previously, this check worked only if the rewrite rule was unconditional]
   864   Now rew can involve either definitions or equalities (either == or =).
   865 
   866 * case_tac provided for compatibility with HOL
   867     (like the old excluded_middle_tac, but with subgoals swapped)
   868 
   869 
   870 *** Internal programming interfaces ***
   871 
   872 * Pure: several new basic modules made available for general use, see
   873 also src/Pure/README;
   874 
   875 * improved the theory data mechanism to support encapsulation (data
   876 kind name replaced by private Object.kind, acting as authorization
   877 key); new type-safe user interface via functor TheoryDataFun; generic
   878 print_data function becomes basically useless;
   879 
   880 * removed global_names compatibility flag -- all theory declarations
   881 are qualified by default;
   882 
   883 * module Pure/Syntax now offers quote / antiquote translation
   884 functions (useful for Hoare logic etc. with implicit dependencies);
   885 see HOL/ex/Antiquote for an example use;
   886 
   887 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   888 cterm -> thm;
   889 
   890 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   891 subgoal;
   892 
   893 * Display.print_goals function moved to Locale.print_goals;
   894 
   895 * standard print function for goals supports current_goals_markers
   896 variable for marking begin of proof, end of proof, start of goal; the
   897 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   898 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   899 for example;
   900 
   901 
   902 
   903 New in Isabelle98 (January 1998)
   904 --------------------------------
   905 
   906 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   907 
   908 * changed lexical syntax of terms / types: dots made part of long
   909 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   910 
   911 * simpset (and claset) reference variable replaced by functions
   912 simpset / simpset_ref;
   913 
   914 * no longer supports theory aliases (via merge) and non-trivial
   915 implicit merge of thms' signatures;
   916 
   917 * most internal names of constants changed due to qualified names;
   918 
   919 * changed Pure/Sequence interface (see Pure/seq.ML);
   920 
   921 
   922 *** General Changes ***
   923 
   924 * hierachically structured name spaces (for consts, types, axms, thms
   925 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   926 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   927 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   928 long_names for fully qualified output names; NOTE: ML programs
   929 (special tactics, packages etc.) referring to internal names may have
   930 to be adapted to cope with fully qualified names; in case of severe
   931 backward campatibility problems try setting 'global_names' at compile
   932 time to have enrything declared within a flat name space; one may also
   933 fine tune name declarations in theories via the 'global' and 'local'
   934 section;
   935 
   936 * reimplemented the implicit simpset and claset using the new anytype
   937 data filed in signatures; references simpset:simpset ref etc. are
   938 replaced by functions simpset:unit->simpset and
   939 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   940 to patch your ML files accordingly;
   941 
   942 * HTML output now includes theory graph data for display with Java
   943 applet or isatool browser; data generated automatically via isatool
   944 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   945 
   946 * defs may now be conditional; improved rewrite_goals_tac to handle
   947 conditional equations;
   948 
   949 * defs now admits additional type arguments, using TYPE('a) syntax;
   950 
   951 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   952 creates a new theory node; implicit merge of thms' signatures is
   953 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   954 transfer:theory->thm->thm in (rare) cases;
   955 
   956 * improved handling of draft signatures / theories; draft thms (and
   957 ctyps, cterms) are automatically promoted to real ones;
   958 
   959 * slightly changed interfaces for oracles: admit many per theory, named
   960 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   961 
   962 * print_goals: optional output of const types (set show_consts and
   963 show_types);
   964 
   965 * improved output of warnings (###) and errors (***);
   966 
   967 * subgoal_tac displays a warning if the new subgoal has type variables;
   968 
   969 * removed old README and Makefiles;
   970 
   971 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   972 
   973 * removed obsolete init_pps and init_database;
   974 
   975 * deleted the obsolete tactical STATE, which was declared by
   976     fun STATE tacfun st = tacfun st st;
   977 
   978 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   979 (which abbreviates $HOME);
   980 
   981 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   982 use isatool fixseq to adapt your ML programs (this works for fully
   983 qualified references to the Sequence structure only!);
   984 
   985 * use_thy no longer requires writable current directory; it always
   986 reloads .ML *and* .thy file, if either one is out of date;
   987 
   988 
   989 *** Classical Reasoner ***
   990 
   991 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   992 tactics that use classical reasoning to simplify a subgoal without
   993 splitting it into several subgoals;
   994 
   995 * Safe_tac: like safe_tac but uses the default claset;
   996 
   997 
   998 *** Simplifier ***
   999 
  1000 * added simplification meta rules:
  1001     (asm_)(full_)simplify: simpset -> thm -> thm;
  1002 
  1003 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1004 logics (again);
  1005 
  1006 * added prems argument to simplification procedures;
  1007 
  1008 * HOL, FOL, ZF: added infix function `addsplits':
  1009   instead of `<simpset> setloop (split_tac <thms>)'
  1010   you can simply write `<simpset> addsplits <thms>'
  1011 
  1012 
  1013 *** Syntax ***
  1014 
  1015 * TYPE('a) syntax for type reflection terms;
  1016 
  1017 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1018 
  1019 * pretty printer: changed order of mixfix annotation preference (again!);
  1020 
  1021 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1022 
  1023 
  1024 *** HOL ***
  1025 
  1026 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1027   with `addloop' of the simplifier to faciliate case splitting in premises.
  1028 
  1029 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1030 
  1031 * HOL/Auth: new protocol proofs including some for the Internet
  1032   protocol TLS;
  1033 
  1034 * HOL/Map: new theory of `maps' a la VDM;
  1035 
  1036 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1037 cancelling out common nat summands from =, <, <= (in)equalities, or
  1038 differences; simplification procedures nat_cancel_factor for
  1039 cancelling common factor from =, <, <= (in)equalities over natural
  1040 sums; nat_cancel contains both kinds of procedures, it is installed by
  1041 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1042 
  1043 * HOL/simplifier: terms of the form
  1044   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1045   are rewritten to
  1046   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1047   and those of the form
  1048   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1049   are rewritten to
  1050   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1051 
  1052 * HOL/datatype
  1053   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1054 
  1055   P(t_case f1 ... fn x) =
  1056      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1057         ...
  1058        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1059      )
  1060 
  1061   and a theorem `split_t_case_asm' of the form
  1062 
  1063   P(t_case f1 ... fn x) =
  1064     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1065         ...
  1066        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1067      )
  1068   which can be added to a simpset via `addsplits'. The existing theorems
  1069   expand_list_case and expand_option_case have been renamed to
  1070   split_list_case and split_option_case.
  1071 
  1072 * HOL/Arithmetic:
  1073   - `pred n' is automatically converted to `n-1'.
  1074     Users are strongly encouraged not to use `pred' any longer,
  1075     because it will disappear altogether at some point.
  1076   - Users are strongly encouraged to write "0 < n" rather than
  1077     "n ~= 0". Theorems and proof tools have been modified towards this
  1078     `standard'.
  1079 
  1080 * HOL/Lists:
  1081   the function "set_of_list" has been renamed "set" (and its theorems too);
  1082   the function "nth" now takes its arguments in the reverse order and
  1083   has acquired the infix notation "!" as in "xs!n".
  1084 
  1085 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1086 
  1087 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1088   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1089 
  1090 * HOL/record: extensible records with schematic structural subtyping
  1091 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1092 still lacks various theorems and concrete record syntax;
  1093 
  1094 
  1095 *** HOLCF ***
  1096 
  1097 * removed "axioms" and "generated by" sections;
  1098 
  1099 * replaced "ops" section by extended "consts" section, which is capable of
  1100   handling the continuous function space "->" directly;
  1101 
  1102 * domain package:
  1103   . proves theorems immediately and stores them in the theory,
  1104   . creates hierachical name space,
  1105   . now uses normal mixfix annotations (instead of cinfix...),
  1106   . minor changes to some names and values (for consistency),
  1107   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1108   . separator between mutual domain defs: changed "," to "and",
  1109   . improved handling of sort constraints;  now they have to
  1110     appear on the left-hand side of the equations only;
  1111 
  1112 * fixed LAM <x,y,zs>.b syntax;
  1113 
  1114 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1115 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1116 
  1117 
  1118 *** FOL and ZF ***
  1119 
  1120 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1121   with `addloop' of the simplifier to faciliate case splitting in premises.
  1122 
  1123 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1124 in HOL, they strip ALL and --> from proved theorems;
  1125 
  1126 
  1127 
  1128 New in Isabelle94-8 (May 1997)
  1129 ------------------------------
  1130 
  1131 *** General Changes ***
  1132 
  1133 * new utilities to build / run / maintain Isabelle etc. (in parts
  1134 still somewhat experimental); old Makefiles etc. still functional;
  1135 
  1136 * new 'Isabelle System Manual';
  1137 
  1138 * INSTALL text, together with ./configure and ./build scripts;
  1139 
  1140 * reimplemented type inference for greater efficiency, better error
  1141 messages and clean internal interface;
  1142 
  1143 * prlim command for dealing with lots of subgoals (an easier way of
  1144 setting goals_limit);
  1145 
  1146 
  1147 *** Syntax ***
  1148 
  1149 * supports alternative (named) syntax tables (parser and pretty
  1150 printer); internal interface is provided by add_modesyntax(_i);
  1151 
  1152 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1153 be used in conjunction with the Isabelle symbol font; uses the
  1154 "symbols" syntax table;
  1155 
  1156 * added token_translation interface (may translate name tokens in
  1157 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1158 the current print_mode); IMPORTANT: user print translation functions
  1159 are responsible for marking newly introduced bounds
  1160 (Syntax.mark_boundT);
  1161 
  1162 * token translations for modes "xterm" and "xterm_color" that display
  1163 names in bold, underline etc. or colors (which requires a color
  1164 version of xterm);
  1165 
  1166 * infixes may now be declared with names independent of their syntax;
  1167 
  1168 * added typed_print_translation (like print_translation, but may
  1169 access type of constant);
  1170 
  1171 
  1172 *** Classical Reasoner ***
  1173 
  1174 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1175 some limitations.  Blast_tac...
  1176   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1177   + ignores elimination rules that don't have the correct format
  1178         (the conclusion MUST be a formula variable)
  1179   + ignores types, which can make HOL proofs fail
  1180   + rules must not require higher-order unification, e.g. apply_type in ZF
  1181     [message "Function Var's argument not a bound variable" relates to this]
  1182   + its proof strategy is more general but can actually be slower
  1183 
  1184 * substitution with equality assumptions no longer permutes other
  1185 assumptions;
  1186 
  1187 * minor changes in semantics of addafter (now called addaltern); renamed
  1188 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1189 (and access functions for it);
  1190 
  1191 * improved combination of classical reasoner and simplifier:
  1192   + functions for handling clasimpsets
  1193   + improvement of addss: now the simplifier is called _after_ the
  1194     safe steps.
  1195   + safe variant of addss called addSss: uses safe simplifications
  1196     _during_ the safe steps. It is more complete as it allows multiple
  1197     instantiations of unknowns (e.g. with slow_tac).
  1198 
  1199 *** Simplifier ***
  1200 
  1201 * added interface for simplification procedures (functions that
  1202 produce *proven* rewrite rules on the fly, depending on current
  1203 redex);
  1204 
  1205 * ordering on terms as parameter (used for ordered rewriting);
  1206 
  1207 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1208 
  1209 * the solver is now split into a safe and an unsafe part.
  1210 This should be invisible for the normal user, except that the
  1211 functions setsolver and addsolver have been renamed to setSolver and
  1212 addSolver; added safe_asm_full_simp_tac;
  1213 
  1214 
  1215 *** HOL ***
  1216 
  1217 * a generic induction tactic `induct_tac' which works for all datatypes and
  1218 also for type `nat';
  1219 
  1220 * a generic case distinction tactic `exhaust_tac' which works for all
  1221 datatypes and also for type `nat';
  1222 
  1223 * each datatype comes with a function `size';
  1224 
  1225 * patterns in case expressions allow tuple patterns as arguments to
  1226 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1227 
  1228 * primrec now also works with type nat;
  1229 
  1230 * recdef: a new declaration form, allows general recursive functions to be
  1231 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1232 
  1233 * the constant for negation has been renamed from "not" to "Not" to
  1234 harmonize with FOL, ZF, LK, etc.;
  1235 
  1236 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1237 infinite lists;
  1238 
  1239 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1240 
  1241 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1242 problems in commutative rings, using axiomatic type classes for + and *;
  1243 
  1244 * more examples in HOL/MiniML and HOL/Auth;
  1245 
  1246 * more default rewrite rules for quantifiers, union/intersection;
  1247 
  1248 * a new constant `arbitrary == @x.False';
  1249 
  1250 * HOLCF/IOA replaces old HOL/IOA;
  1251 
  1252 * HOLCF changes: derived all rules and arities
  1253   + axiomatic type classes instead of classes
  1254   + typedef instead of faking type definitions
  1255   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1256   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1257   + eliminated the types void, one, tr
  1258   + use unit lift and bool lift (with translations) instead of one and tr
  1259   + eliminated blift from Lift3.thy (use Def instead of blift)
  1260   all eliminated rules are derived as theorems --> no visible changes ;
  1261 
  1262 
  1263 *** ZF ***
  1264 
  1265 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1266 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1267 as ZF_cs addSIs [equalityI];
  1268 
  1269 
  1270 
  1271 New in Isabelle94-7 (November 96)
  1272 ---------------------------------
  1273 
  1274 * allowing negative levels (as offsets) in prlev and choplev;
  1275 
  1276 * super-linear speedup for large simplifications;
  1277 
  1278 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1279 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1280 FAIL); can suppress it using the command Delsimps (ex_simps @
  1281 all_simps); De Morgan laws are also now included, by default;
  1282 
  1283 * improved printing of ==>  :  ~:
  1284 
  1285 * new object-logic "Sequents" adds linear logic, while replacing LK
  1286 and Modal (thanks to Sara Kalvala);
  1287 
  1288 * HOL/Auth: correctness proofs for authentication protocols;
  1289 
  1290 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1291 examples on HOL/Auth);
  1292 
  1293 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1294 the rewriter and classical reasoner simultaneously;
  1295 
  1296 * function uresult no longer returns theorems in "standard" format;
  1297 regain previous version by: val uresult = standard o uresult;
  1298 
  1299 
  1300 
  1301 New in Isabelle94-6
  1302 -------------------
  1303 
  1304 * oracles -- these establish an interface between Isabelle and trusted
  1305 external reasoners, which may deliver results as theorems;
  1306 
  1307 * proof objects (in particular record all uses of oracles);
  1308 
  1309 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1310 
  1311 * "constdefs" section in theory files;
  1312 
  1313 * "primrec" section (HOL) no longer requires names;
  1314 
  1315 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1316 
  1317 
  1318 
  1319 New in Isabelle94-5
  1320 -------------------
  1321 
  1322 * reduced space requirements;
  1323 
  1324 * automatic HTML generation from theories;
  1325 
  1326 * theory files no longer require "..." (quotes) around most types;
  1327 
  1328 * new examples, including two proofs of the Church-Rosser theorem;
  1329 
  1330 * non-curried (1994) version of HOL is no longer distributed;
  1331 
  1332 
  1333 
  1334 New in Isabelle94-4
  1335 -------------------
  1336 
  1337 * greatly reduced space requirements;
  1338 
  1339 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1340 
  1341 * searchable theorem database (see the section "Retrieving theorems" on
  1342 page 8 of the Reference Manual);
  1343 
  1344 * new examples, including Grabczewski's monumental case study of the
  1345 Axiom of Choice;
  1346 
  1347 * The previous version of HOL renamed to Old_HOL;
  1348 
  1349 * The new version of HOL (previously called CHOL) uses a curried syntax
  1350 for functions.  Application looks like f a b instead of f(a,b);
  1351 
  1352 * Mutually recursive inductive definitions finally work in HOL;
  1353 
  1354 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1355 translates to the operator "split";
  1356 
  1357 
  1358 
  1359 New in Isabelle94-3
  1360 -------------------
  1361 
  1362 * new infix operator, addss, allowing the classical reasoner to
  1363 perform simplification at each step of its search.  Example:
  1364         fast_tac (cs addss ss)
  1365 
  1366 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1367 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1368 look like (a,b) instead of <a,b>;
  1369 
  1370 * PLEASE NOTE: CHOL will eventually replace HOL!
  1371 
  1372 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1373 It translates to the operator "split".  A new theory of integers is available;
  1374 
  1375 * In ZF, integer numerals now denote two's-complement binary integers.
  1376 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1377 
  1378 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1379 of the Axiom of Choice;
  1380 
  1381 
  1382 
  1383 New in Isabelle94-2
  1384 -------------------
  1385 
  1386 * Significantly faster resolution;
  1387 
  1388 * the different sections in a .thy file can now be mixed and repeated
  1389 freely;
  1390 
  1391 * Database of theorems for FOL, HOL and ZF.  New
  1392 commands including qed, qed_goal and bind_thm store theorems in the database.
  1393 
  1394 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1395 a given theory (thms_of), or find out what theory a theorem was proved in
  1396 (theory_of_thm);
  1397 
  1398 * Bugs fixed in the inductive definition and datatype packages;
  1399 
  1400 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1401 and HOL_dup_cs obsolete;
  1402 
  1403 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1404 have been removed;
  1405 
  1406 * Simpler definition of function space in ZF;
  1407 
  1408 * new results about cardinal and ordinal arithmetic in ZF;
  1409 
  1410 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1411 types;
  1412 
  1413 
  1414 $Id$