NEWS
author nipkow
Tue May 23 09:08:18 2000 +0200 (2000-05-23)
changeset 8925 f4599af94b83
parent 8921 7c04c98132c4
child 8967 00f18476ac15
permissions -rw-r--r--
SetInterval
     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: the constant for f``x is now "image" rather than "op ``";
    18 
    19 * HOL: the cartesian product is now "<*>" instead of "Times"; the
    20 lexicographic product is now "<*lex*>" instead of "**";
    21 
    22 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    23 
    24 * HOL: simplification no longer dives into case-expressions
    25 
    26 * HOL: the recursion equations generated by 'recdef' are now called
    27 f.simps instead of f.rules;
    28 
    29 * HOL: theory Sexp now in HOL/Induct examples (used to be part of main
    30 HOL, but was unused); should better use HOL's datatype package anyway;
    31 
    32 * HOL/Real: "rabs" replaced by overloaded "abs" function;
    33 
    34 * HOL/ML: even fewer consts are declared as global (see theories Ord,
    35 Lfp, Gfp, WF); this only affects ML packages that refer to const names
    36 internally;
    37 
    38 * Isar: changed syntax of local blocks from {{ }} to { };
    39 
    40 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    41 
    42 * LaTeX: several improvements of isabelle.sty;
    43 
    44 
    45 *** Document preparation ***
    46 
    47 * isatool mkdir provides easy setup of Isabelle session directories,
    48 including proper document sources;
    49 
    50 * generated LaTeX sources are now deleted after successful run
    51 (isatool document -c); may retain a copy somewhere else via -D option
    52 of isatool usedir;
    53 
    54 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    55 style files, achieving self-contained LaTeX sources;
    56 
    57 * old-style theories now produce (crude) LaTeX output as well;
    58 
    59 
    60 *** Isar ***
    61 
    62 * Pure: local results and corresponding term bindings are now subject
    63 to Hindley-Milner polymorphism (similar to ML); this accommodates
    64 incremental type-inference nicely;
    65 
    66 * Pure: new 'obtain' language element supports generalized existence
    67 reasoning;
    68 
    69 * Pure: new calculational elements 'moreover' and 'ultimately' support
    70 plain accumulation of results, without applying any rules yet;
    71 
    72 * Pure: scalable support for case-analysis type proofs: new 'case'
    73 language element refers to local contexts symbolically, as produced by
    74 certain proof methods; internally, case names are attached to theorems
    75 as "tags";
    76 
    77 * Pure: changed syntax of local blocks from {{ }} to { };
    78 
    79 * Pure: syntax of sorts made inner, i.e. have to write "{a, b, c}"
    80 instead of {a, b, c};
    81 
    82 * Pure now provides its own version of intro/elim/dest attributes;
    83 useful for building new logics, but beware of confusion with the
    84 Provers/classical ones;
    85 
    86 * Provers: splitter support (via 'split' attribute and 'simp' method
    87 modifier); 'simp' method: 'only:' modifier removes loopers as well
    88 (including splits);
    89 
    90 * HOL: new proof method 'cases' and improved version of 'induct' now
    91 support named cases; major packages (inductive, datatype, primrec,
    92 recdef) support case names and properly name parameters;
    93 
    94 * HOL: removed 'case_split' thm binding, should use 'cases' proof
    95 method anyway;
    96 
    97 * names of theorems etc. may be natural numbers as well;
    98 
    99 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
   100 
   101 * 'pr' command: optional goals_limit argument; no longer prints theory
   102 contexts, but only proof states;
   103 
   104 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   105 additional print modes to be specified; e.g. "pr(latex)" will print
   106 proof state according to the Isabelle LaTeX style;
   107 
   108 * improved support for emulating tactic scripts, including proof
   109 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
   110 'induct_tac' (for HOL datatypes);
   111 
   112 * simplified (more robust) goal selection of proof methods: 1st goal,
   113 all goals, or explicit goal specifier (tactic emulation); thus 'proof
   114 method scripts' have to be in depth-first order;
   115 
   116 * tuned 'let' syntax: replace 'as' keyword by 'and';
   117 
   118 * theory command 'hide' removes declarations from class/type/const
   119 name spaces;
   120 
   121 
   122 *** HOL ***
   123 
   124 * HOL/Algebra: new theory of rings and univariate polynomials, by
   125 Clemens Ballarin;
   126 
   127 * HOL/record: fixed select-update simplification procedure to handle
   128 extended records as well; admit "r" as field name;
   129 
   130 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
   131 Arithmetic, by Thomas M Rasmussen;
   132 
   133 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
   134 basically a generalized version of de-Bruijn representation; very
   135 useful in avoiding lifting all operations;
   136 
   137 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   138 
   139 * greatly improved simplification involving numerals of type nat & int, e.g.
   140    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   141    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   142   two terms #m*u and #n*u are replaced by #(m+n)*u
   143     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   144   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   145     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   146 
   147 * HOL: new version of "case_tac" subsumes both boolean case split and
   148 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   149 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   150 
   151 * HOL: simplification no longer dives into case-expressions: only the
   152 selector expression is simplified, but not the remaining arms. To
   153 enable full simplification of case-expressions for datatype t, you
   154 need to remove t.weak_case_cong from the simpset, either permanently
   155 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   156 
   157 * HOL/recdef: the recursion equations generated by 'recdef' for
   158 function 'f' are now called f.simps instead of f.rules; if all
   159 termination conditions are proved automatically, these simplification
   160 rules are added to the simpset, as in primrec; rules may be named
   161 individually as well, resulting in a separate list of theorems for
   162 each equation;
   163 
   164 * HOL: new (overloaded) notation for the set of elements below/above some
   165 element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   166 
   167 * HOL: theorems impI, allI, ballI bound as "strip";
   168 
   169 * theory Sexp now in HOL/Induct examples (used to be part of main HOL,
   170 but was unused);
   171 
   172 * fewer consts declared as global (e.g. have to refer to "Lfp.lfp"
   173 instead of "lfp" internally; affects ML packages only);
   174 
   175 
   176 *** General ***
   177 
   178 * improved name spaces: ambiguous output is qualified; support for
   179 hiding of names;
   180 
   181 * compression of ML heaps images may now be controlled via -c option
   182 of isabelle and isatool usedir (currently only observed by Poly/ML);
   183 
   184 * ML: new combinators |>> and |>>> for incremental transformations
   185 with secondary results (e.g. certain theory extensions):
   186 
   187 
   188 
   189 New in Isabelle99 (October 1999)
   190 --------------------------------
   191 
   192 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   193 
   194 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   195 are no longer simplified.  (This allows the simplifier to unfold recursive
   196 functional programs.)  To restore the old behaviour, declare
   197 
   198     Delcongs [if_weak_cong];
   199 
   200 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   201 complement;
   202 
   203 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   204 
   205 * HOL/datatype: mutual_induct_tac no longer exists --
   206   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   207 
   208 * HOL/typedef: fixed type inference for representing set; type
   209 arguments now have to occur explicitly on the rhs as type constraints;
   210 
   211 * ZF: The con_defs part of an inductive definition may no longer refer
   212 to constants declared in the same theory;
   213 
   214 * HOL, ZF: the function mk_cases, generated by the inductive
   215 definition package, has lost an argument.  To simplify its result, it
   216 uses the default simpset instead of a supplied list of theorems.
   217 
   218 * HOL/List: the constructors of type list are now Nil and Cons;
   219 
   220 * Simplifier: the type of the infix ML functions
   221         setSSolver addSSolver setSolver addSolver
   222 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   223 for packaging solvers. A solver is created via
   224         mk_solver: string -> (thm list -> int -> tactic) -> solver
   225 where the string argument is only a comment.
   226 
   227 
   228 *** Proof tools ***
   229 
   230 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   231 decision procedure for linear arithmetic. Currently it is used for
   232 types `nat', `int', and `real' in HOL (see below); it can, should and
   233 will be instantiated for other types and logics as well.
   234 
   235 * The simplifier now accepts rewrite rules with flexible heads, eg
   236      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   237   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   238   matching.
   239 
   240 
   241 *** General ***
   242 
   243 * New Isabelle/Isar subsystem provides an alternative to traditional
   244 tactical theorem proving; together with the ProofGeneral/isar user
   245 interface it offers an interactive environment for developing human
   246 readable proof documents (Isar == Intelligible semi-automated
   247 reasoning); for further information see isatool doc isar-ref,
   248 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   249 
   250 * improved presentation of theories: better HTML markup (including
   251 colors), graph views in several sizes; isatool usedir now provides a
   252 proper interface for user theories (via -P option); actual document
   253 preparation based on (PDF)LaTeX is available as well (for new-style
   254 theories only); see isatool doc system for more information;
   255 
   256 * native support for Proof General, both for classic Isabelle and
   257 Isabelle/Isar;
   258 
   259 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   260 using the graph browser tool;
   261 
   262 * Isabelle manuals now also available as PDF;
   263 
   264 * theory loader rewritten from scratch (may not be fully
   265 bug-compatible); old loadpath variable has been replaced by show_path,
   266 add_path, del_path, reset_path functions; new operations such as
   267 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   268 isatool doc ref);
   269 
   270 * improved isatool install: option -k creates KDE application icon,
   271 option -p DIR installs standalone binaries;
   272 
   273 * added ML_PLATFORM setting (useful for cross-platform installations);
   274 more robust handling of platform specific ML images for SML/NJ;
   275 
   276 * the settings environment is now statically scoped, i.e. it is never
   277 created again in sub-processes invoked from isabelle, isatool, or
   278 Isabelle;
   279 
   280 * path element specification '~~' refers to '$ISABELLE_HOME';
   281 
   282 * in locales, the "assumes" and "defines" parts may be omitted if
   283 empty;
   284 
   285 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   286 long arrows);
   287 
   288 * new print_mode "HTML";
   289 
   290 * new flag show_tags controls display of tags of theorems (which are
   291 basically just comments that may be attached by some tools);
   292 
   293 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   294 mode and goal output format:
   295 
   296 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   297 244c244
   298 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   299 ---
   300 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   301 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   302 181c181
   303 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   304 ---
   305 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   306 
   307 * function bind_thms stores lists of theorems (cf. bind_thm);
   308 
   309 * new shorthand tactics ftac, eatac, datac, fatac;
   310 
   311 * qed (and friends) now accept "" as result name; in that case the
   312 theorem is not stored, but proper checks and presentation of the
   313 result still apply;
   314 
   315 * theorem database now also indexes constants "Trueprop", "all",
   316 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   317 
   318 
   319 *** HOL ***
   320 
   321 ** HOL arithmetic **
   322 
   323 * There are now decision procedures for linear arithmetic over nat and
   324 int:
   325 
   326 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   327 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   328 are treated as atomic; subformulae not involving type `nat' or `int'
   329 are ignored; quantified subformulae are ignored unless they are
   330 positive universal or negative existential. The tactic has to be
   331 invoked by hand and can be a little bit slow. In particular, the
   332 running time is exponential in the number of occurrences of `min' and
   333 `max', and `-' on `nat'.
   334 
   335 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   336 (negated) (in)equalities among the premises and the conclusion into
   337 account (i.e. no compound formulae) and does not know about `min' and
   338 `max', and `-' on `nat'. It is fast and is used automatically by the
   339 simplifier.
   340 
   341 NB: At the moment, these decision procedures do not cope with mixed
   342 nat/int formulae where the two parts interact, such as `m < n ==>
   343 int(m) < int(n)'.
   344 
   345 * HOL/Numeral provides a generic theory of numerals (encoded
   346 efficiently as bit strings); setup for types nat/int/real is in place;
   347 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   348 int, existing theories and proof scripts may require a few additional
   349 type constraints;
   350 
   351 * integer division and remainder can now be performed on constant
   352 arguments;
   353 
   354 * many properties of integer multiplication, division and remainder
   355 are now available;
   356 
   357 * An interface to the Stanford Validity Checker (SVC) is available through the
   358 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   359 are proved automatically.  SVC must be installed separately, and its results
   360 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   361 invocation of the underlying oracle).  For SVC see
   362   http://verify.stanford.edu/SVC
   363 
   364 * IsaMakefile: the HOL-Real target now builds an actual image;
   365 
   366 
   367 ** HOL misc **
   368 
   369 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   370 (in Isabelle/Isar) -- by Gertrud Bauer;
   371 
   372 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   373 analysis for assembly languages with subtypes;
   374 
   375 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   376 -- avoids syntactic ambiguities and treats state, transition, and
   377 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   378 changed syntax and (many) tactics;
   379 
   380 * HOL/inductive: Now also handles more general introduction rules such
   381   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   382   theorems are now maintained within the theory (maintained via the
   383   "mono" attribute);
   384 
   385 * HOL/datatype: Now also handles arbitrarily branching datatypes
   386   (using function types) such as
   387 
   388   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   389 
   390 * HOL/record: record_simproc (part of the default simpset) takes care
   391 of selectors applied to updated records; record_split_tac is no longer
   392 part of the default claset; update_defs may now be removed from the
   393 simpset in many cases; COMPATIBILITY: old behavior achieved by
   394 
   395   claset_ref () := claset() addSWrapper record_split_wrapper;
   396   Delsimprocs [record_simproc]
   397 
   398 * HOL/typedef: fixed type inference for representing set; type
   399 arguments now have to occur explicitly on the rhs as type constraints;
   400 
   401 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   402 names rather than an ML expression;
   403 
   404 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   405 supplied later.  Program schemes can be defined, such as
   406     "While B C s = (if B s then While B C (C s) else s)"
   407 where the well-founded relation can be chosen after B and C have been given.
   408 
   409 * HOL/List: the constructors of type list are now Nil and Cons;
   410 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   411 course, ML tools referring to List.list.op # etc. have to be adapted;
   412 
   413 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   414 disabled by default; run isabelle with option -m HOL to get back to
   415 the original Gordon/HOL-style output;
   416 
   417 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   418 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   419 
   420 * HOL basic syntax simplified (more orthogonal): all variants of
   421 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   422 Eps operator is provided as well: "SOME x. P[x]";
   423 
   424 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   425 
   426 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   427 thus available for user theories;
   428 
   429 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   430 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   431 time;
   432 
   433 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   434 several times and then mp;
   435 
   436 
   437 *** LK ***
   438 
   439 * the notation <<...>> is now available as a notation for sequences of
   440 formulas;
   441 
   442 * the simplifier is now installed
   443 
   444 * the axiom system has been generalized (thanks to Soren Heilmann)
   445 
   446 * the classical reasoner now has a default rule database
   447 
   448 
   449 *** ZF ***
   450 
   451 * new primrec section allows primitive recursive functions to be given
   452 directly (as in HOL) over datatypes and the natural numbers;
   453 
   454 * new tactics induct_tac and exhaust_tac for induction (or case
   455 analysis) over datatypes and the natural numbers;
   456 
   457 * the datatype declaration of type T now defines the recursor T_rec;
   458 
   459 * simplification automatically does freeness reasoning for datatype
   460 constructors;
   461 
   462 * automatic type-inference, with AddTCs command to insert new
   463 type-checking rules;
   464 
   465 * datatype introduction rules are now added as Safe Introduction rules
   466 to the claset;
   467 
   468 * the syntax "if P then x else y" is now available in addition to
   469 if(P,x,y);
   470 
   471 
   472 *** Internal programming interfaces ***
   473 
   474 * tuned simplifier trace output; new flag debug_simp;
   475 
   476 * structures Vartab / Termtab (instances of TableFun) offer efficient
   477 tables indexed by indexname_ord / term_ord (compatible with aconv);
   478 
   479 * AxClass.axclass_tac lost the theory argument;
   480 
   481 * tuned current_goals_markers semantics: begin / end goal avoids
   482 printing empty lines;
   483 
   484 * removed prs and prs_fn hook, which was broken because it did not
   485 include \n in its semantics, forcing writeln to add one
   486 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   487 string -> unit if you really want to output text without newline;
   488 
   489 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   490 plain output, interface builders may have to enable 'isabelle_font'
   491 mode to get Isabelle font glyphs as before;
   492 
   493 * refined token_translation interface; INCOMPATIBILITY: output length
   494 now of type real instead of int;
   495 
   496 * theory loader actions may be traced via new ThyInfo.add_hook
   497 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   498 your own database of information attached to *whole* theories -- as
   499 opposed to intra-theory data slots offered via TheoryDataFun;
   500 
   501 * proper handling of dangling sort hypotheses (at last!);
   502 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   503 extra sort hypotheses that can be witnessed from the type signature;
   504 the force_strip_shyps flag is gone, any remaining shyps are simply
   505 left in the theorem (with a warning issued by strip_shyps_warning);
   506 
   507 
   508 
   509 New in Isabelle98-1 (October 1998)
   510 ----------------------------------
   511 
   512 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   513 
   514 * several changes of automated proof tools;
   515 
   516 * HOL: major changes to the inductive and datatype packages, including
   517 some minor incompatibilities of theory syntax;
   518 
   519 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   520 called `inj_on';
   521 
   522 * HOL: removed duplicate thms in Arith:
   523   less_imp_add_less  should be replaced by  trans_less_add1
   524   le_imp_add_le      should be replaced by  trans_le_add1
   525 
   526 * HOL: unary minus is now overloaded (new type constraints may be
   527 required);
   528 
   529 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   530 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   531 now taken as an integer constant.
   532 
   533 * Pure: ML function 'theory_of' renamed to 'theory';
   534 
   535 
   536 *** Proof tools ***
   537 
   538 * Simplifier:
   539   1. Asm_full_simp_tac is now more aggressive.
   540      1. It will sometimes reorient premises if that increases their power to
   541         simplify.
   542      2. It does no longer proceed strictly from left to right but may also
   543         rotate premises to achieve further simplification.
   544      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   545      old Asm_full_simp_tac in that it does not rotate premises.
   546   2. The simplifier now knows a little bit about nat-arithmetic.
   547 
   548 * Classical reasoner: wrapper mechanism for the classical reasoner now
   549 allows for selected deletion of wrappers, by introduction of names for
   550 wrapper functionals.  This implies that addbefore, addSbefore,
   551 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   552 and that adding two tactics with the same name overwrites the first
   553 one (emitting a warning).
   554   type wrapper = (int -> tactic) -> (int -> tactic)
   555   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   556   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   557   delWrapper, delSWrapper: claset *  string            -> claset
   558   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   559 
   560 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   561 semantics; addbefore now affects only the unsafe part of step_tac
   562 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   563 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   564 by Force_tac;
   565 
   566 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   567 compWrapper; added safe wrapper (and access functions for it);
   568 
   569 * HOL/split_all_tac is now much faster and fails if there is nothing
   570 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   571 and the names of the automatically generated variables have changed.
   572 split_all_tac has moved within claset() from unsafe wrappers to safe
   573 wrappers, which means that !!-bound variables are split much more
   574 aggressively, and safe_tac and clarify_tac now split such variables.
   575 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   576 Note: the same holds for record_split_tac, which does the job of
   577 split_all_tac for record fields.
   578 
   579 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   580 permanently to the default simpset using Addsplits just like
   581 Addsimps. They can be removed via Delsplits just like
   582 Delsimps. Lower-case versions are also available.
   583 
   584 * HOL/Simplifier: The rule split_if is now part of the default
   585 simpset. This means that the simplifier will eliminate all occurrences
   586 of if-then-else in the conclusion of a goal. To prevent this, you can
   587 either remove split_if completely from the default simpset by
   588 `Delsplits [split_if]' or remove it in a specific call of the
   589 simplifier using `... delsplits [split_if]'.  You can also add/delete
   590 other case splitting rules to/from the default simpset: every datatype
   591 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   592 t is the name of the datatype).
   593 
   594 * Classical reasoner / Simplifier combination: new force_tac (and
   595 derivatives Force_tac, force) combines rewriting and classical
   596 reasoning (and whatever other tools) similarly to auto_tac, but is
   597 aimed to solve the given subgoal completely.
   598 
   599 
   600 *** General ***
   601 
   602 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   603 and `goalw': the theory is no longer needed as an explicit argument -
   604 the current theory context is used; assumptions are no longer returned
   605 at the ML-level unless one of them starts with ==> or !!; it is
   606 recommended to convert to these new commands using isatool fixgoal
   607 (backup your sources first!);
   608 
   609 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   610 the current theory context, and 'theory' to lookup stored theories;
   611 
   612 * new theory section 'locale' for declaring constants, assumptions and
   613 definitions that have local scope;
   614 
   615 * new theory section 'nonterminals' for purely syntactic types;
   616 
   617 * new theory section 'setup' for generic ML setup functions
   618 (e.g. package initialization);
   619 
   620 * the distribution now includes Isabelle icons: see
   621 lib/logo/isabelle-{small,tiny}.xpm;
   622 
   623 * isatool install - install binaries with absolute references to
   624 ISABELLE_HOME/bin;
   625 
   626 * isatool logo -- create instances of the Isabelle logo (as EPS);
   627 
   628 * print mode 'emacs' reserved for Isamode;
   629 
   630 * support multiple print (ast) translations per constant name;
   631 
   632 * theorems involving oracles are now printed with a suffixed [!];
   633 
   634 
   635 *** HOL ***
   636 
   637 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   638 
   639 * HOL/inductive package reorganized and improved: now supports mutual
   640 definitions such as
   641 
   642   inductive EVEN ODD
   643     intrs
   644       null "0 : EVEN"
   645       oddI "n : EVEN ==> Suc n : ODD"
   646       evenI "n : ODD ==> Suc n : EVEN"
   647 
   648 new theorem list "elims" contains an elimination rule for each of the
   649 recursive sets; inductive definitions now handle disjunctive premises
   650 correctly (also ZF);
   651 
   652 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   653 "mutual_induct" no longer exists - the induction rule is always
   654 contained in "induct";
   655 
   656 
   657 * HOL/datatype package re-implemented and greatly improved: now
   658 supports mutually recursive datatypes such as
   659 
   660   datatype
   661     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   662             | SUM ('a aexp) ('a aexp)
   663             | DIFF ('a aexp) ('a aexp)
   664             | NUM 'a
   665   and
   666     'a bexp = LESS ('a aexp) ('a aexp)
   667             | AND ('a bexp) ('a bexp)
   668             | OR ('a bexp) ('a bexp)
   669 
   670 as well as indirectly recursive datatypes such as
   671 
   672   datatype
   673     ('a, 'b) term = Var 'a
   674                   | App 'b ((('a, 'b) term) list)
   675 
   676 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   677 induction on mutually / indirectly recursive datatypes.
   678 
   679 Primrec equations are now stored in theory and can be accessed via
   680 <function_name>.simps.
   681 
   682 INCOMPATIBILITIES:
   683 
   684   - Theories using datatypes must now have theory Datatype as an
   685     ancestor.
   686   - The specific <typename>.induct_tac no longer exists - use the
   687     generic induct_tac instead.
   688   - natE has been renamed to nat.exhaust - use exhaust_tac
   689     instead of res_inst_tac ... natE. Note that the variable
   690     names in nat.exhaust differ from the names in natE, this
   691     may cause some "fragile" proofs to fail.
   692   - The theorems split_<typename>_case and split_<typename>_case_asm
   693     have been renamed to <typename>.split and <typename>.split_asm.
   694   - Since default sorts of type variables are now handled correctly,
   695     some datatype definitions may have to be annotated with explicit
   696     sort constraints.
   697   - Primrec definitions no longer require function name and type
   698     of recursive argument.
   699 
   700 Consider using isatool fixdatatype to adapt your theories and proof
   701 scripts to the new package (backup your sources first!).
   702 
   703 
   704 * HOL/record package: considerably improved implementation; now
   705 includes concrete syntax for record types, terms, updates; theorems
   706 for surjective pairing and splitting !!-bound record variables; proof
   707 support is as follows:
   708 
   709   1) standard conversions (selectors or updates applied to record
   710 constructor terms) are part of the standard simpset;
   711 
   712   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   713 made part of standard simpset and claset via addIffs;
   714 
   715   3) a tactic for record field splitting (record_split_tac) is part of
   716 the standard claset (addSWrapper);
   717 
   718 To get a better idea about these rules you may retrieve them via
   719 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   720 the name of your record type.
   721 
   722 The split tactic 3) conceptually simplifies by the following rule:
   723 
   724   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   725 
   726 Thus any record variable that is bound by meta-all will automatically
   727 blow up into some record constructor term, consequently the
   728 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   729 solve record problems automatically.
   730 
   731 
   732 * reorganized the main HOL image: HOL/Integ and String loaded by
   733 default; theory Main includes everything;
   734 
   735 * automatic simplification of integer sums and comparisons, using cancellation;
   736 
   737 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   738 
   739 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   740 
   741 * many new identities for unions, intersections, set difference, etc.;
   742 
   743 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   744 called split_if, split_split, split_sum_case and split_nat_case (to go
   745 with add/delsplits);
   746 
   747 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   748 (?x::unit) = (); this is made part of the default simpset, which COULD
   749 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   750 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   751 unit_abs_eta_conv is added in order to counter the effect of
   752 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   753 %u.f();
   754 
   755 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   756 makes more sense);
   757 
   758 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   759   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   760   disjointness reasoning but breaking a few old proofs.
   761 
   762 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   763 to 'converse' from 'inverse' (for compatibility with ZF and some
   764 literature);
   765 
   766 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   767 the well-founded relation;
   768 
   769 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   770     Compl A.  The "Compl" syntax remains available as input syntax for this
   771     release ONLY.
   772 
   773 * HOL/Update: new theory of function updates:
   774     f(a:=b) == %x. if x=a then b else f x
   775 may also be iterated as in f(a:=b,c:=d,...);
   776 
   777 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   778 
   779 * HOL/List:
   780   - new function list_update written xs[i:=v] that updates the i-th
   781     list position. May also be iterated as in xs[i:=a,j:=b,...].
   782   - new function `upt' written [i..j(] which generates the list
   783     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   784     bound write [i..j], which is a shorthand for [i..j+1(].
   785   - new lexicographic orderings and corresponding wellfoundedness theorems.
   786 
   787 * HOL/Arith:
   788   - removed 'pred' (predecessor) function;
   789   - generalized some theorems about n-1;
   790   - many new laws about "div" and "mod";
   791   - new laws about greatest common divisors (see theory ex/Primes);
   792 
   793 * HOL/Relation: renamed the relational operator r^-1 "converse"
   794 instead of "inverse";
   795 
   796 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   797   of the multiset ordering;
   798 
   799 * directory HOL/Real: a construction of the reals using Dedekind cuts
   800   (not included by default);
   801 
   802 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   803 
   804 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   805   programs, i.e. different program variables may have different types.
   806 
   807 * calling (stac rew i) now fails if "rew" has no effect on the goal
   808   [previously, this check worked only if the rewrite rule was unconditional]
   809   Now rew can involve either definitions or equalities (either == or =).
   810 
   811 
   812 *** ZF ***
   813 
   814 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   815   only the theorems proved on ZF.ML;
   816 
   817 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   818   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   819   disjointness reasoning but breaking a few old proofs.
   820 
   821 * ZF/Update: new theory of function updates
   822     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   823   may also be iterated as in f(a:=b,c:=d,...);
   824 
   825 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   826 
   827 * calling (stac rew i) now fails if "rew" has no effect on the goal
   828   [previously, this check worked only if the rewrite rule was unconditional]
   829   Now rew can involve either definitions or equalities (either == or =).
   830 
   831 * case_tac provided for compatibility with HOL
   832     (like the old excluded_middle_tac, but with subgoals swapped)
   833 
   834 
   835 *** Internal programming interfaces ***
   836 
   837 * Pure: several new basic modules made available for general use, see
   838 also src/Pure/README;
   839 
   840 * improved the theory data mechanism to support encapsulation (data
   841 kind name replaced by private Object.kind, acting as authorization
   842 key); new type-safe user interface via functor TheoryDataFun; generic
   843 print_data function becomes basically useless;
   844 
   845 * removed global_names compatibility flag -- all theory declarations
   846 are qualified by default;
   847 
   848 * module Pure/Syntax now offers quote / antiquote translation
   849 functions (useful for Hoare logic etc. with implicit dependencies);
   850 see HOL/ex/Antiquote for an example use;
   851 
   852 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   853 cterm -> thm;
   854 
   855 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   856 subgoal;
   857 
   858 * Display.print_goals function moved to Locale.print_goals;
   859 
   860 * standard print function for goals supports current_goals_markers
   861 variable for marking begin of proof, end of proof, start of goal; the
   862 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   863 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   864 for example;
   865 
   866 
   867 
   868 New in Isabelle98 (January 1998)
   869 --------------------------------
   870 
   871 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   872 
   873 * changed lexical syntax of terms / types: dots made part of long
   874 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   875 
   876 * simpset (and claset) reference variable replaced by functions
   877 simpset / simpset_ref;
   878 
   879 * no longer supports theory aliases (via merge) and non-trivial
   880 implicit merge of thms' signatures;
   881 
   882 * most internal names of constants changed due to qualified names;
   883 
   884 * changed Pure/Sequence interface (see Pure/seq.ML);
   885 
   886 
   887 *** General Changes ***
   888 
   889 * hierachically structured name spaces (for consts, types, axms, thms
   890 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   891 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   892 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   893 long_names for fully qualified output names; NOTE: ML programs
   894 (special tactics, packages etc.) referring to internal names may have
   895 to be adapted to cope with fully qualified names; in case of severe
   896 backward campatibility problems try setting 'global_names' at compile
   897 time to have enrything declared within a flat name space; one may also
   898 fine tune name declarations in theories via the 'global' and 'local'
   899 section;
   900 
   901 * reimplemented the implicit simpset and claset using the new anytype
   902 data filed in signatures; references simpset:simpset ref etc. are
   903 replaced by functions simpset:unit->simpset and
   904 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   905 to patch your ML files accordingly;
   906 
   907 * HTML output now includes theory graph data for display with Java
   908 applet or isatool browser; data generated automatically via isatool
   909 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   910 
   911 * defs may now be conditional; improved rewrite_goals_tac to handle
   912 conditional equations;
   913 
   914 * defs now admits additional type arguments, using TYPE('a) syntax;
   915 
   916 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   917 creates a new theory node; implicit merge of thms' signatures is
   918 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   919 transfer:theory->thm->thm in (rare) cases;
   920 
   921 * improved handling of draft signatures / theories; draft thms (and
   922 ctyps, cterms) are automatically promoted to real ones;
   923 
   924 * slightly changed interfaces for oracles: admit many per theory, named
   925 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   926 
   927 * print_goals: optional output of const types (set show_consts and
   928 show_types);
   929 
   930 * improved output of warnings (###) and errors (***);
   931 
   932 * subgoal_tac displays a warning if the new subgoal has type variables;
   933 
   934 * removed old README and Makefiles;
   935 
   936 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   937 
   938 * removed obsolete init_pps and init_database;
   939 
   940 * deleted the obsolete tactical STATE, which was declared by
   941     fun STATE tacfun st = tacfun st st;
   942 
   943 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   944 (which abbreviates $HOME);
   945 
   946 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   947 use isatool fixseq to adapt your ML programs (this works for fully
   948 qualified references to the Sequence structure only!);
   949 
   950 * use_thy no longer requires writable current directory; it always
   951 reloads .ML *and* .thy file, if either one is out of date;
   952 
   953 
   954 *** Classical Reasoner ***
   955 
   956 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   957 tactics that use classical reasoning to simplify a subgoal without
   958 splitting it into several subgoals;
   959 
   960 * Safe_tac: like safe_tac but uses the default claset;
   961 
   962 
   963 *** Simplifier ***
   964 
   965 * added simplification meta rules:
   966     (asm_)(full_)simplify: simpset -> thm -> thm;
   967 
   968 * simplifier.ML no longer part of Pure -- has to be loaded by object
   969 logics (again);
   970 
   971 * added prems argument to simplification procedures;
   972 
   973 * HOL, FOL, ZF: added infix function `addsplits':
   974   instead of `<simpset> setloop (split_tac <thms>)'
   975   you can simply write `<simpset> addsplits <thms>'
   976 
   977 
   978 *** Syntax ***
   979 
   980 * TYPE('a) syntax for type reflection terms;
   981 
   982 * no longer handles consts with name "" -- declare as 'syntax' instead;
   983 
   984 * pretty printer: changed order of mixfix annotation preference (again!);
   985 
   986 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   987 
   988 
   989 *** HOL ***
   990 
   991 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   992   with `addloop' of the simplifier to faciliate case splitting in premises.
   993 
   994 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   995 
   996 * HOL/Auth: new protocol proofs including some for the Internet
   997   protocol TLS;
   998 
   999 * HOL/Map: new theory of `maps' a la VDM;
  1000 
  1001 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1002 cancelling out common nat summands from =, <, <= (in)equalities, or
  1003 differences; simplification procedures nat_cancel_factor for
  1004 cancelling common factor from =, <, <= (in)equalities over natural
  1005 sums; nat_cancel contains both kinds of procedures, it is installed by
  1006 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1007 
  1008 * HOL/simplifier: terms of the form
  1009   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1010   are rewritten to
  1011   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1012   and those of the form
  1013   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1014   are rewritten to
  1015   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1016 
  1017 * HOL/datatype
  1018   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1019 
  1020   P(t_case f1 ... fn x) =
  1021      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1022         ...
  1023        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1024      )
  1025 
  1026   and a theorem `split_t_case_asm' of the form
  1027 
  1028   P(t_case f1 ... fn x) =
  1029     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1030         ...
  1031        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1032      )
  1033   which can be added to a simpset via `addsplits'. The existing theorems
  1034   expand_list_case and expand_option_case have been renamed to
  1035   split_list_case and split_option_case.
  1036 
  1037 * HOL/Arithmetic:
  1038   - `pred n' is automatically converted to `n-1'.
  1039     Users are strongly encouraged not to use `pred' any longer,
  1040     because it will disappear altogether at some point.
  1041   - Users are strongly encouraged to write "0 < n" rather than
  1042     "n ~= 0". Theorems and proof tools have been modified towards this
  1043     `standard'.
  1044 
  1045 * HOL/Lists:
  1046   the function "set_of_list" has been renamed "set" (and its theorems too);
  1047   the function "nth" now takes its arguments in the reverse order and
  1048   has acquired the infix notation "!" as in "xs!n".
  1049 
  1050 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1051 
  1052 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1053   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1054 
  1055 * HOL/record: extensible records with schematic structural subtyping
  1056 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1057 still lacks various theorems and concrete record syntax;
  1058 
  1059 
  1060 *** HOLCF ***
  1061 
  1062 * removed "axioms" and "generated by" sections;
  1063 
  1064 * replaced "ops" section by extended "consts" section, which is capable of
  1065   handling the continuous function space "->" directly;
  1066 
  1067 * domain package:
  1068   . proves theorems immediately and stores them in the theory,
  1069   . creates hierachical name space,
  1070   . now uses normal mixfix annotations (instead of cinfix...),
  1071   . minor changes to some names and values (for consistency),
  1072   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1073   . separator between mutual domain defs: changed "," to "and",
  1074   . improved handling of sort constraints;  now they have to
  1075     appear on the left-hand side of the equations only;
  1076 
  1077 * fixed LAM <x,y,zs>.b syntax;
  1078 
  1079 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1080 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1081 
  1082 
  1083 *** FOL and ZF ***
  1084 
  1085 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1086   with `addloop' of the simplifier to faciliate case splitting in premises.
  1087 
  1088 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1089 in HOL, they strip ALL and --> from proved theorems;
  1090 
  1091 
  1092 
  1093 New in Isabelle94-8 (May 1997)
  1094 ------------------------------
  1095 
  1096 *** General Changes ***
  1097 
  1098 * new utilities to build / run / maintain Isabelle etc. (in parts
  1099 still somewhat experimental); old Makefiles etc. still functional;
  1100 
  1101 * new 'Isabelle System Manual';
  1102 
  1103 * INSTALL text, together with ./configure and ./build scripts;
  1104 
  1105 * reimplemented type inference for greater efficiency, better error
  1106 messages and clean internal interface;
  1107 
  1108 * prlim command for dealing with lots of subgoals (an easier way of
  1109 setting goals_limit);
  1110 
  1111 
  1112 *** Syntax ***
  1113 
  1114 * supports alternative (named) syntax tables (parser and pretty
  1115 printer); internal interface is provided by add_modesyntax(_i);
  1116 
  1117 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1118 be used in conjunction with the Isabelle symbol font; uses the
  1119 "symbols" syntax table;
  1120 
  1121 * added token_translation interface (may translate name tokens in
  1122 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1123 the current print_mode); IMPORTANT: user print translation functions
  1124 are responsible for marking newly introduced bounds
  1125 (Syntax.mark_boundT);
  1126 
  1127 * token translations for modes "xterm" and "xterm_color" that display
  1128 names in bold, underline etc. or colors (which requires a color
  1129 version of xterm);
  1130 
  1131 * infixes may now be declared with names independent of their syntax;
  1132 
  1133 * added typed_print_translation (like print_translation, but may
  1134 access type of constant);
  1135 
  1136 
  1137 *** Classical Reasoner ***
  1138 
  1139 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1140 some limitations.  Blast_tac...
  1141   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1142   + ignores elimination rules that don't have the correct format
  1143         (the conclusion MUST be a formula variable)
  1144   + ignores types, which can make HOL proofs fail
  1145   + rules must not require higher-order unification, e.g. apply_type in ZF
  1146     [message "Function Var's argument not a bound variable" relates to this]
  1147   + its proof strategy is more general but can actually be slower
  1148 
  1149 * substitution with equality assumptions no longer permutes other
  1150 assumptions;
  1151 
  1152 * minor changes in semantics of addafter (now called addaltern); renamed
  1153 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1154 (and access functions for it);
  1155 
  1156 * improved combination of classical reasoner and simplifier:
  1157   + functions for handling clasimpsets
  1158   + improvement of addss: now the simplifier is called _after_ the
  1159     safe steps.
  1160   + safe variant of addss called addSss: uses safe simplifications
  1161     _during_ the safe steps. It is more complete as it allows multiple
  1162     instantiations of unknowns (e.g. with slow_tac).
  1163 
  1164 *** Simplifier ***
  1165 
  1166 * added interface for simplification procedures (functions that
  1167 produce *proven* rewrite rules on the fly, depending on current
  1168 redex);
  1169 
  1170 * ordering on terms as parameter (used for ordered rewriting);
  1171 
  1172 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1173 
  1174 * the solver is now split into a safe and an unsafe part.
  1175 This should be invisible for the normal user, except that the
  1176 functions setsolver and addsolver have been renamed to setSolver and
  1177 addSolver; added safe_asm_full_simp_tac;
  1178 
  1179 
  1180 *** HOL ***
  1181 
  1182 * a generic induction tactic `induct_tac' which works for all datatypes and
  1183 also for type `nat';
  1184 
  1185 * a generic case distinction tactic `exhaust_tac' which works for all
  1186 datatypes and also for type `nat';
  1187 
  1188 * each datatype comes with a function `size';
  1189 
  1190 * patterns in case expressions allow tuple patterns as arguments to
  1191 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1192 
  1193 * primrec now also works with type nat;
  1194 
  1195 * recdef: a new declaration form, allows general recursive functions to be
  1196 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1197 
  1198 * the constant for negation has been renamed from "not" to "Not" to
  1199 harmonize with FOL, ZF, LK, etc.;
  1200 
  1201 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1202 infinite lists;
  1203 
  1204 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1205 
  1206 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1207 problems in commutative rings, using axiomatic type classes for + and *;
  1208 
  1209 * more examples in HOL/MiniML and HOL/Auth;
  1210 
  1211 * more default rewrite rules for quantifiers, union/intersection;
  1212 
  1213 * a new constant `arbitrary == @x.False';
  1214 
  1215 * HOLCF/IOA replaces old HOL/IOA;
  1216 
  1217 * HOLCF changes: derived all rules and arities
  1218   + axiomatic type classes instead of classes
  1219   + typedef instead of faking type definitions
  1220   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1221   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1222   + eliminated the types void, one, tr
  1223   + use unit lift and bool lift (with translations) instead of one and tr
  1224   + eliminated blift from Lift3.thy (use Def instead of blift)
  1225   all eliminated rules are derived as theorems --> no visible changes ;
  1226 
  1227 
  1228 *** ZF ***
  1229 
  1230 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1231 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1232 as ZF_cs addSIs [equalityI];
  1233 
  1234 
  1235 
  1236 New in Isabelle94-7 (November 96)
  1237 ---------------------------------
  1238 
  1239 * allowing negative levels (as offsets) in prlev and choplev;
  1240 
  1241 * super-linear speedup for large simplifications;
  1242 
  1243 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1244 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1245 FAIL); can suppress it using the command Delsimps (ex_simps @
  1246 all_simps); De Morgan laws are also now included, by default;
  1247 
  1248 * improved printing of ==>  :  ~:
  1249 
  1250 * new object-logic "Sequents" adds linear logic, while replacing LK
  1251 and Modal (thanks to Sara Kalvala);
  1252 
  1253 * HOL/Auth: correctness proofs for authentication protocols;
  1254 
  1255 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1256 examples on HOL/Auth);
  1257 
  1258 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1259 the rewriter and classical reasoner simultaneously;
  1260 
  1261 * function uresult no longer returns theorems in "standard" format;
  1262 regain previous version by: val uresult = standard o uresult;
  1263 
  1264 
  1265 
  1266 New in Isabelle94-6
  1267 -------------------
  1268 
  1269 * oracles -- these establish an interface between Isabelle and trusted
  1270 external reasoners, which may deliver results as theorems;
  1271 
  1272 * proof objects (in particular record all uses of oracles);
  1273 
  1274 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1275 
  1276 * "constdefs" section in theory files;
  1277 
  1278 * "primrec" section (HOL) no longer requires names;
  1279 
  1280 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1281 
  1282 
  1283 
  1284 New in Isabelle94-5
  1285 -------------------
  1286 
  1287 * reduced space requirements;
  1288 
  1289 * automatic HTML generation from theories;
  1290 
  1291 * theory files no longer require "..." (quotes) around most types;
  1292 
  1293 * new examples, including two proofs of the Church-Rosser theorem;
  1294 
  1295 * non-curried (1994) version of HOL is no longer distributed;
  1296 
  1297 
  1298 
  1299 New in Isabelle94-4
  1300 -------------------
  1301 
  1302 * greatly reduced space requirements;
  1303 
  1304 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1305 
  1306 * searchable theorem database (see the section "Retrieving theorems" on
  1307 page 8 of the Reference Manual);
  1308 
  1309 * new examples, including Grabczewski's monumental case study of the
  1310 Axiom of Choice;
  1311 
  1312 * The previous version of HOL renamed to Old_HOL;
  1313 
  1314 * The new version of HOL (previously called CHOL) uses a curried syntax
  1315 for functions.  Application looks like f a b instead of f(a,b);
  1316 
  1317 * Mutually recursive inductive definitions finally work in HOL;
  1318 
  1319 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1320 translates to the operator "split";
  1321 
  1322 
  1323 
  1324 New in Isabelle94-3
  1325 -------------------
  1326 
  1327 * new infix operator, addss, allowing the classical reasoner to
  1328 perform simplification at each step of its search.  Example:
  1329         fast_tac (cs addss ss)
  1330 
  1331 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1332 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1333 look like (a,b) instead of <a,b>;
  1334 
  1335 * PLEASE NOTE: CHOL will eventually replace HOL!
  1336 
  1337 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1338 It translates to the operator "split".  A new theory of integers is available;
  1339 
  1340 * In ZF, integer numerals now denote two's-complement binary integers.
  1341 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1342 
  1343 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1344 of the Axiom of Choice;
  1345 
  1346 
  1347 
  1348 New in Isabelle94-2
  1349 -------------------
  1350 
  1351 * Significantly faster resolution;
  1352 
  1353 * the different sections in a .thy file can now be mixed and repeated
  1354 freely;
  1355 
  1356 * Database of theorems for FOL, HOL and ZF.  New
  1357 commands including qed, qed_goal and bind_thm store theorems in the database.
  1358 
  1359 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1360 a given theory (thms_of), or find out what theory a theorem was proved in
  1361 (theory_of_thm);
  1362 
  1363 * Bugs fixed in the inductive definition and datatype packages;
  1364 
  1365 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1366 and HOL_dup_cs obsolete;
  1367 
  1368 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1369 have been removed;
  1370 
  1371 * Simpler definition of function space in ZF;
  1372 
  1373 * new results about cardinal and ordinal arithmetic in ZF;
  1374 
  1375 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1376 types;
  1377 
  1378 
  1379 $Id$