NEWS
author oheimb
Mon Sep 21 23:16:25 1998 +0200 (1998-09-21)
changeset 5524 38f2a518a811
parent 5490 85855f65d0c6
child 5526 e7617b57a3e6
permissions -rw-r--r--
*** empty log message ***
     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 * several changes of proof tools;
    11 
    12 * HOL: new version of inductive and datatype;
    13 
    14 * HOL: major changes to the inductive and datatype packages;
    15 
    16 * HOL: renamed r^-1 to 'converse' from 'inverse'; `inj_onto' is now
    17 called `inj_on';
    18 
    19 * HOL: removed duplicate thms in Arith:
    20   less_imp_add_less  should be replaced by  trans_less_add1
    21   le_imp_add_le      should be replaced by  trans_le_add1
    22 
    23 * HOL: unary - is now overloaded (new type constraints may be required);
    24 
    25 * Pure: ML function 'theory_of' replaced by 'theory';
    26 
    27 
    28 *** Proof tools ***
    29 
    30 * Simplifier: Asm_full_simp_tac is now more aggressive.
    31   1. It will sometimes reorient premises if that increases their power to
    32      simplify.
    33   2. It does no longer proceed strictly from left to right but may also
    34      rotate premises to achieve further simplification.
    35   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    36   old Asm_full_simp_tac in that it does not rotate premises.
    37 
    38 * Classical reasoner: wrapper mechanism for the classical reasoner now
    39 allows for selected deletion of wrappers, by introduction of names for
    40 wrapper functionals.  This implies that addbefore, addSbefore,
    41 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    42 and that adding two tactics with the same name overwrites the first
    43 one (emitting a warning).
    44   type wrapper = (int -> tactic) -> (int -> tactic)
    45   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    46   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    47   delWrapper, delSWrapper: claset *  string            -> claset
    48   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    49 
    50 * Classical reasoner: addbefore / addSbefore now have APPEND / ORELSE semantics;
    51   addbefore now affects only the unsafe part of step_tac etc.;
    52   This affects addss/auto_tac/force_tac, so EXISTING (INSTABLE) PROOFS MAY FAIL, but
    53   most proofs should be fixable easily, e.g. by replacing Auto_tac by Force_tac.
    54 
    55 * Classical reasoner: setwrapper to setWrapper and compwrapper to compWrapper; 
    56   added safe wrapper (and access functions for it);
    57 
    58 * HOL/split_all_tac is now much faster and fails if there is nothing
    59 to split.  Existing (fragile) proofs may require adaption because the
    60 order and the names of the automatically generated variables have
    61 changed.  split_all_tac has moved within claset() from unsafe wrappers
    62 to safe wrappers, which means that !!-bound variables are split much
    63 more aggressively, and safe_tac and clarify_tac now split such
    64 variables.  If this splitting is not appropriate, use delSWrapper
    65 "split_all_tac".
    66 
    67 * HOL/Simplifier:
    68 
    69  - Rewrite rules for case distinctions can now be added permanently to
    70    the default simpset using Addsplits just like Addsimps. They can be
    71    removed via Delsplits just like Delsimps. Lower-case versions are
    72    also available.
    73 
    74  - The rule split_if is now part of the default simpset. This means
    75    that the simplifier will eliminate all occurrences of if-then-else
    76    in the conclusion of a goal. To prevent this, you can either remove
    77    split_if completely from the default simpset by `Delsplits
    78    [split_if]' or remove it in a specific call of the simplifier using
    79    `... delsplits [split_if]'.  You can also add/delete other case
    80    splitting rules to/from the default simpset: every datatype
    81    generates suitable rules `split_t_case' and `split_t_case_asm'
    82    (where t is the name of the datatype).
    83 
    84 * Classical reasoner - Simplifier combination: new force_tac (and
    85 derivatives Force_tac, force) combines rewriting and classical
    86 reasoning (and whatever other tools) similarly to auto_tac, but is
    87 aimed to solve the given subgoal completely;
    88 
    89 
    90 *** General ***
    91 
    92 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
    93 and `goalw': the theory is no longer needed as an explicit argument -
    94 the current theory context is used; assumptions are no longer returned
    95 at the ML-level unless one of them starts with ==> or !!; it is
    96 recommended to convert to these new commands using isatool fixgoal
    97 (backup your sources first!);
    98 
    99 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   100 the current theory context, and 'theory' to lookup stored theories;
   101 
   102 * new theory section 'nonterminals' for purely syntactic types;
   103 
   104 * new theory section 'setup' for generic ML setup functions
   105 (e.g. package initialization);
   106 
   107 * the distribution now includes Isabelle icons: see
   108 lib/logo/isabelle-{small,tiny}.xpm;
   109 
   110 * isatool install - install binaries with absolute references to
   111 ISABELLE_HOME/bin;
   112 
   113 * print mode 'emacs' reserved for Isamode;
   114 
   115 
   116 *** HOL ***
   117 
   118 * HOL/inductive package reorganized and improved: now supports mutual
   119 definitions such as
   120 
   121   inductive EVEN ODD
   122     intrs
   123       null "0 : EVEN"
   124       oddI "n : EVEN ==> Suc n : ODD"
   125       evenI "n : ODD ==> Suc n : EVEN"
   126 
   127 new theorem list "elims" contains an elimination rule for each of the
   128 recursive sets; inductive definitions now handle disjunctive premises
   129 correctly (also ZF);
   130 
   131 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   132 "mutual_induct" no longer exists - the induction rule is always
   133 contained in "induct";
   134 
   135 
   136 * HOL/datatype package re-implemented and greatly improved: now
   137 supports mutually recursive datatypes such as
   138 
   139   datatype
   140     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   141             | SUM ('a aexp) ('a aexp)
   142             | DIFF ('a aexp) ('a aexp)
   143             | NUM 'a
   144   and
   145     'a bexp = LESS ('a aexp) ('a aexp)
   146             | AND ('a bexp) ('a bexp)
   147             | OR ('a bexp) ('a bexp)
   148 
   149 as well as indirectly recursive datatypes such as
   150 
   151   datatype
   152     ('a, 'b) term = Var 'a
   153                   | App 'b ((('a, 'b) term) list)
   154 
   155 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   156 induction on mutually / indirectly recursive datatypes.
   157 
   158 Primrec equations are now stored in theory and can be accessed via
   159 <function_name>.simps.
   160 
   161 INCOMPATIBILITIES:
   162 
   163   - Theories using datatypes must now have theory Datatype as an
   164     ancestor.
   165   - The specific <typename>.induct_tac no longer exists - use the
   166     generic induct_tac instead.
   167   - natE has been renamed to nat.exhaust - use exhaust_tac
   168     instead of res_inst_tac ... natE. Note that the variable
   169     names in nat.exhaust differ from the names in natE, this
   170     may cause some "fragile" proofs to fail.
   171   - The theorems split_<typename>_case and split_<typename>_case_asm
   172     have been renamed to <typename>.split and <typename>.split_asm.
   173   - Since default sorts of type variables are now handled correctly,
   174     some datatype definitions may have to be annotated with explicit
   175     sort constraints.
   176   - Primrec definitions no longer require function name and type
   177     of recursive argument.
   178 
   179 Consider using isatool fixdatatype to adapt your theories and proof
   180 scripts to the new package (backup your sources first!).
   181 
   182 
   183 * HOL/record package: now includes concrete syntax for record types,
   184 terms, updates; still lacks important theorems, like surjective
   185 pairing and split;
   186 
   187 * reorganized the main HOL image: HOL/Integ and String loaded by
   188 default; theory Main includes everything;
   189 
   190 * added option_map_eq_Some to the default simpset claset;
   191 
   192 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   193 
   194 * many new identities for unions, intersections, set difference, etc.;
   195 
   196 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   197 called split_if, split_split, split_sum_case and split_nat_case (to go
   198 with add/delsplits);
   199 
   200 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   201 (?x::unit) = (); this is made part of the default simpset, which COULD
   202 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   203 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   204 unit_abs_eta_conv is added in order to counter the effect of
   205 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   206 %u.f();
   207 
   208 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   209 makes more sense);
   210 
   211 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   212   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   213   disjointness reasoning but breaking a few old proofs.
   214 
   215 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   216 to 'converse' from 'inverse' (for compatibility with ZF and some
   217 literature);
   218 
   219 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   220 the well-founded relation;
   221 
   222 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   223     Compl A.  The "Compl" syntax remains available as input syntax for this
   224     release ONLY.
   225 
   226 * HOL/Update: new theory of function updates:
   227     f(a:=b) == %x. if x=a then b else f x
   228 may also be iterated as in f(a:=b,c:=d,...);
   229 
   230 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   231 
   232 * HOL/List:
   233   - new function list_update written xs[i:=v] that updates the i-th
   234     list position. May also be iterated as in xs[i:=a,j:=b,...].
   235   - new function `upt' written [i..j(] which generates the list
   236     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   237     bound write [i..j], which is a shorthand for [i..j+1(].
   238   - new lexicographic orderings and corresponding wellfoundedness theorems.
   239 
   240 * HOL/Arith:
   241   - removed 'pred' (predecessor) function;
   242   - generalized some theorems about n-1;
   243   - many new laws about "div" and "mod";
   244   - new laws about greatest common divisors (see theory ex/Primes);
   245 
   246 * HOL/Relation: renamed the relational operator r^-1 "converse"
   247 instead of "inverse";
   248 
   249 * directory HOL/Real: a construction of the reals using Dedekind cuts
   250 (not included by default);
   251 
   252 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   253 
   254 * calling (stac rew i) now fails if "rew" has no effect on the goal
   255   [previously, this check worked only if the rewrite rule was unconditional]
   256   Now rew can involve either definitions or equalities (either == or =).
   257 
   258 
   259 *** ZF ***
   260 
   261 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   262   only the theorems proved on ZF.ML;
   263 
   264 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   265   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   266   disjointness reasoning but breaking a few old proofs.
   267 
   268 * ZF/Update: new theory of function updates
   269     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   270   may also be iterated as in f(a:=b,c:=d,...);
   271 
   272 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   273 
   274 * calling (stac rew i) now fails if "rew" has no effect on the goal
   275   [previously, this check worked only if the rewrite rule was unconditional]
   276   Now rew can involve either definitions or equalities (either == or =).
   277 
   278 * case_tac provided for compatibility with HOL
   279     (like the old excluded_middle_tac, but with subgoals swapped)
   280 
   281 
   282 *** Internal programming interfaces ***
   283 
   284 * Pure: several new basic modules made available for general use, see
   285 also src/Pure/README;
   286 
   287 * improved the theory data mechanism to support encapsulation (data
   288 kind name replaced by private Object.kind, acting as authorization
   289 key); new type-safe user interface via functor TheoryDataFun; generic
   290 print_data function becomes basically useless;
   291 
   292 * removed global_names compatibility flag -- all theory declarations
   293 are qualified by default;
   294 
   295 * module Pure/Syntax now offers quote / antiquote translation
   296 functions (useful for Hoare logic etc. with implicit dependencies);
   297 see HOL/ex/Antiquote for an example use;
   298 
   299 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   300 cterm -> thm;
   301 
   302 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   303 subgoal;
   304 
   305 * Display.print_goals function moved to Locale.print_goals;
   306 
   307 
   308 
   309 New in Isabelle98 (January 1998)
   310 --------------------------------
   311 
   312 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   313 
   314 * changed lexical syntax of terms / types: dots made part of long
   315 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   316 
   317 * simpset (and claset) reference variable replaced by functions
   318 simpset / simpset_ref;
   319 
   320 * no longer supports theory aliases (via merge) and non-trivial
   321 implicit merge of thms' signatures;
   322 
   323 * most internal names of constants changed due to qualified names;
   324 
   325 * changed Pure/Sequence interface (see Pure/seq.ML);
   326 
   327 
   328 *** General Changes ***
   329 
   330 * hierachically structured name spaces (for consts, types, axms, thms
   331 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   332 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   333 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   334 long_names for fully qualified output names; NOTE: ML programs
   335 (special tactics, packages etc.) referring to internal names may have
   336 to be adapted to cope with fully qualified names; in case of severe
   337 backward campatibility problems try setting 'global_names' at compile
   338 time to have enrything declared within a flat name space; one may also
   339 fine tune name declarations in theories via the 'global' and 'local'
   340 section;
   341 
   342 * reimplemented the implicit simpset and claset using the new anytype
   343 data filed in signatures; references simpset:simpset ref etc. are
   344 replaced by functions simpset:unit->simpset and
   345 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   346 to patch your ML files accordingly;
   347 
   348 * HTML output now includes theory graph data for display with Java
   349 applet or isatool browser; data generated automatically via isatool
   350 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   351 
   352 * defs may now be conditional; improved rewrite_goals_tac to handle
   353 conditional equations;
   354 
   355 * defs now admits additional type arguments, using TYPE('a) syntax;
   356 
   357 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   358 creates a new theory node; implicit merge of thms' signatures is
   359 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   360 transfer:theory->thm->thm in (rare) cases;
   361 
   362 * improved handling of draft signatures / theories; draft thms (and
   363 ctyps, cterms) are automatically promoted to real ones;
   364 
   365 * slightly changed interfaces for oracles: admit many per theory, named
   366 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   367 
   368 * print_goals: optional output of const types (set show_consts and
   369 show_types);
   370 
   371 * improved output of warnings (###) and errors (***);
   372 
   373 * subgoal_tac displays a warning if the new subgoal has type variables;
   374 
   375 * removed old README and Makefiles;
   376 
   377 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   378 
   379 * removed obsolete init_pps and init_database;
   380 
   381 * deleted the obsolete tactical STATE, which was declared by
   382     fun STATE tacfun st = tacfun st st;
   383 
   384 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   385 (which abbreviates $HOME);
   386 
   387 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   388 use isatool fixseq to adapt your ML programs (this works for fully
   389 qualified references to the Sequence structure only!);
   390 
   391 * use_thy no longer requires writable current directory; it always
   392 reloads .ML *and* .thy file, if either one is out of date;
   393 
   394 
   395 *** Classical Reasoner ***
   396 
   397 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   398 tactics that use classical reasoning to simplify a subgoal without
   399 splitting it into several subgoals;
   400 
   401 * Safe_tac: like safe_tac but uses the default claset;
   402 
   403 
   404 *** Simplifier ***
   405 
   406 * added simplification meta rules:
   407     (asm_)(full_)simplify: simpset -> thm -> thm;
   408 
   409 * simplifier.ML no longer part of Pure -- has to be loaded by object
   410 logics (again);
   411 
   412 * added prems argument to simplification procedures;
   413 
   414 * HOL, FOL, ZF: added infix function `addsplits':
   415   instead of `<simpset> setloop (split_tac <thms>)'
   416   you can simply write `<simpset> addsplits <thms>'
   417 
   418 
   419 *** Syntax ***
   420 
   421 * TYPE('a) syntax for type reflection terms;
   422 
   423 * no longer handles consts with name "" -- declare as 'syntax' instead;
   424 
   425 * pretty printer: changed order of mixfix annotation preference (again!);
   426 
   427 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   428 
   429 
   430 *** HOL ***
   431 
   432 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   433   with `addloop' of the simplifier to faciliate case splitting in premises.
   434 
   435 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   436 
   437 * HOL/Auth: new protocol proofs including some for the Internet
   438   protocol TLS;
   439 
   440 * HOL/Map: new theory of `maps' a la VDM;
   441 
   442 * HOL/simplifier: simplification procedures nat_cancel_sums for
   443 cancelling out common nat summands from =, <, <= (in)equalities, or
   444 differences; simplification procedures nat_cancel_factor for
   445 cancelling common factor from =, <, <= (in)equalities over natural
   446 sums; nat_cancel contains both kinds of procedures, it is installed by
   447 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   448 
   449 * HOL/simplifier: terms of the form
   450   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   451   are rewritten to
   452   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   453   and those of the form
   454   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   455   are rewritten to
   456   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   457 
   458 * HOL/datatype
   459   Each datatype `t' now comes with a theorem `split_t_case' of the form
   460 
   461   P(t_case f1 ... fn x) =
   462      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   463         ...
   464        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   465      )
   466 
   467   and a theorem `split_t_case_asm' of the form
   468 
   469   P(t_case f1 ... fn x) =
   470     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   471         ...
   472        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   473      )
   474   which can be added to a simpset via `addsplits'. The existing theorems
   475   expand_list_case and expand_option_case have been renamed to
   476   split_list_case and split_option_case.
   477 
   478 * HOL/Arithmetic:
   479   - `pred n' is automatically converted to `n-1'.
   480     Users are strongly encouraged not to use `pred' any longer,
   481     because it will disappear altogether at some point.
   482   - Users are strongly encouraged to write "0 < n" rather than
   483     "n ~= 0". Theorems and proof tools have been modified towards this
   484     `standard'.
   485 
   486 * HOL/Lists:
   487   the function "set_of_list" has been renamed "set" (and its theorems too);
   488   the function "nth" now takes its arguments in the reverse order and
   489   has acquired the infix notation "!" as in "xs!n".
   490 
   491 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   492 
   493 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   494   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   495 
   496 * HOL/record: extensible records with schematic structural subtyping
   497 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   498 still lacks various theorems and concrete record syntax;
   499 
   500 
   501 *** HOLCF ***
   502 
   503 * removed "axioms" and "generated by" sections;
   504 
   505 * replaced "ops" section by extended "consts" section, which is capable of
   506   handling the continuous function space "->" directly;
   507 
   508 * domain package:
   509   . proves theorems immediately and stores them in the theory,
   510   . creates hierachical name space,
   511   . now uses normal mixfix annotations (instead of cinfix...),
   512   . minor changes to some names and values (for consistency),
   513   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   514   . separator between mutual domain defs: changed "," to "and",
   515   . improved handling of sort constraints;  now they have to
   516     appear on the left-hand side of the equations only;
   517 
   518 * fixed LAM <x,y,zs>.b syntax;
   519 
   520 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   521 adm (%x. P (t x)), where P is chainfinite and t continuous;
   522 
   523 
   524 *** FOL and ZF ***
   525 
   526 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   527   with `addloop' of the simplifier to faciliate case splitting in premises.
   528 
   529 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   530 in HOL, they strip ALL and --> from proved theorems;
   531 
   532 
   533 
   534 New in Isabelle94-8 (May 1997)
   535 ------------------------------
   536 
   537 *** General Changes ***
   538 
   539 * new utilities to build / run / maintain Isabelle etc. (in parts
   540 still somewhat experimental); old Makefiles etc. still functional;
   541 
   542 * new 'Isabelle System Manual';
   543 
   544 * INSTALL text, together with ./configure and ./build scripts;
   545 
   546 * reimplemented type inference for greater efficiency, better error
   547 messages and clean internal interface;
   548 
   549 * prlim command for dealing with lots of subgoals (an easier way of
   550 setting goals_limit);
   551 
   552 
   553 *** Syntax ***
   554 
   555 * supports alternative (named) syntax tables (parser and pretty
   556 printer); internal interface is provided by add_modesyntax(_i);
   557 
   558 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   559 be used in conjunction with the Isabelle symbol font; uses the
   560 "symbols" syntax table;
   561 
   562 * added token_translation interface (may translate name tokens in
   563 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   564 the current print_mode); IMPORTANT: user print translation functions
   565 are responsible for marking newly introduced bounds
   566 (Syntax.mark_boundT);
   567 
   568 * token translations for modes "xterm" and "xterm_color" that display
   569 names in bold, underline etc. or colors (which requires a color
   570 version of xterm);
   571 
   572 * infixes may now be declared with names independent of their syntax;
   573 
   574 * added typed_print_translation (like print_translation, but may
   575 access type of constant);
   576 
   577 
   578 *** Classical Reasoner ***
   579 
   580 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   581 some limitations.  Blast_tac...
   582   + ignores addss, addbefore, addafter; this restriction is intrinsic
   583   + ignores elimination rules that don't have the correct format
   584 	(the conclusion MUST be a formula variable)
   585   + ignores types, which can make HOL proofs fail
   586   + rules must not require higher-order unification, e.g. apply_type in ZF
   587     [message "Function Var's argument not a bound variable" relates to this]
   588   + its proof strategy is more general but can actually be slower
   589 
   590 * substitution with equality assumptions no longer permutes other
   591 assumptions;
   592 
   593 * minor changes in semantics of addafter (now called addaltern); renamed
   594 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   595 (and access functions for it);
   596 
   597 * improved combination of classical reasoner and simplifier: 
   598   + functions for handling clasimpsets
   599   + improvement of addss: now the simplifier is called _after_ the
   600     safe steps.
   601   + safe variant of addss called addSss: uses safe simplifications
   602     _during_ the safe steps. It is more complete as it allows multiple 
   603     instantiations of unknowns (e.g. with slow_tac).
   604 
   605 *** Simplifier ***
   606 
   607 * added interface for simplification procedures (functions that
   608 produce *proven* rewrite rules on the fly, depending on current
   609 redex);
   610 
   611 * ordering on terms as parameter (used for ordered rewriting);
   612 
   613 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   614 
   615 * the solver is now split into a safe and an unsafe part.
   616 This should be invisible for the normal user, except that the
   617 functions setsolver and addsolver have been renamed to setSolver and
   618 addSolver; added safe_asm_full_simp_tac;
   619 
   620 
   621 *** HOL ***
   622 
   623 * a generic induction tactic `induct_tac' which works for all datatypes and
   624 also for type `nat';
   625 
   626 * a generic case distinction tactic `exhaust_tac' which works for all
   627 datatypes and also for type `nat';
   628 
   629 * each datatype comes with a function `size';
   630 
   631 * patterns in case expressions allow tuple patterns as arguments to
   632 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   633 
   634 * primrec now also works with type nat;
   635 
   636 * recdef: a new declaration form, allows general recursive functions to be
   637 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   638 
   639 * the constant for negation has been renamed from "not" to "Not" to
   640 harmonize with FOL, ZF, LK, etc.;
   641 
   642 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   643 infinite lists;
   644 
   645 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   646 
   647 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   648 problems in commutative rings, using axiomatic type classes for + and *;
   649 
   650 * more examples in HOL/MiniML and HOL/Auth;
   651 
   652 * more default rewrite rules for quantifiers, union/intersection;
   653 
   654 * a new constant `arbitrary == @x.False';
   655 
   656 * HOLCF/IOA replaces old HOL/IOA;
   657 
   658 * HOLCF changes: derived all rules and arities 
   659   + axiomatic type classes instead of classes 
   660   + typedef instead of faking type definitions
   661   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   662   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   663   + eliminated the types void, one, tr
   664   + use unit lift and bool lift (with translations) instead of one and tr
   665   + eliminated blift from Lift3.thy (use Def instead of blift)
   666   all eliminated rules are derived as theorems --> no visible changes ;
   667 
   668 
   669 *** ZF ***
   670 
   671 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   672 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   673 as ZF_cs addSIs [equalityI];
   674 
   675 
   676 
   677 New in Isabelle94-7 (November 96)
   678 ---------------------------------
   679 
   680 * allowing negative levels (as offsets) in prlev and choplev;
   681 
   682 * super-linear speedup for large simplifications;
   683 
   684 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   685 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   686 FAIL); can suppress it using the command Delsimps (ex_simps @
   687 all_simps); De Morgan laws are also now included, by default;
   688 
   689 * improved printing of ==>  :  ~:
   690 
   691 * new object-logic "Sequents" adds linear logic, while replacing LK
   692 and Modal (thanks to Sara Kalvala);
   693 
   694 * HOL/Auth: correctness proofs for authentication protocols;
   695 
   696 * HOL: new auto_tac combines rewriting and classical reasoning (many
   697 examples on HOL/Auth);
   698 
   699 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   700 the rewriter and classical reasoner simultaneously;
   701 
   702 * function uresult no longer returns theorems in "standard" format;
   703 regain previous version by: val uresult = standard o uresult;
   704 
   705 
   706 
   707 New in Isabelle94-6
   708 -------------------
   709 
   710 * oracles -- these establish an interface between Isabelle and trusted
   711 external reasoners, which may deliver results as theorems;
   712 
   713 * proof objects (in particular record all uses of oracles);
   714 
   715 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   716 
   717 * "constdefs" section in theory files;
   718 
   719 * "primrec" section (HOL) no longer requires names;
   720 
   721 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   722 
   723 
   724 
   725 New in Isabelle94-5
   726 -------------------
   727 
   728 * reduced space requirements;
   729 
   730 * automatic HTML generation from theories;
   731 
   732 * theory files no longer require "..." (quotes) around most types;
   733 
   734 * new examples, including two proofs of the Church-Rosser theorem;
   735 
   736 * non-curried (1994) version of HOL is no longer distributed;
   737 
   738 
   739 
   740 New in Isabelle94-4
   741 -------------------
   742 
   743 * greatly reduced space requirements;
   744 
   745 * theory files (.thy) no longer require \...\ escapes at line breaks;
   746 
   747 * searchable theorem database (see the section "Retrieving theorems" on 
   748 page 8 of the Reference Manual);
   749 
   750 * new examples, including Grabczewski's monumental case study of the
   751 Axiom of Choice;
   752 
   753 * The previous version of HOL renamed to Old_HOL;
   754 
   755 * The new version of HOL (previously called CHOL) uses a curried syntax 
   756 for functions.  Application looks like f a b instead of f(a,b);
   757 
   758 * Mutually recursive inductive definitions finally work in HOL;
   759 
   760 * In ZF, pattern-matching on tuples is now available in all abstractions and
   761 translates to the operator "split";
   762 
   763 
   764 
   765 New in Isabelle94-3
   766 -------------------
   767 
   768 * new infix operator, addss, allowing the classical reasoner to 
   769 perform simplification at each step of its search.  Example:
   770 	fast_tac (cs addss ss)
   771 
   772 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   773 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   774 look like (a,b) instead of <a,b>;
   775 
   776 * PLEASE NOTE: CHOL will eventually replace HOL!
   777 
   778 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   779 It translates to the operator "split".  A new theory of integers is available;
   780 
   781 * In ZF, integer numerals now denote two's-complement binary integers.
   782 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   783 
   784 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   785 of the Axiom of Choice;
   786 
   787 
   788 
   789 New in Isabelle94-2
   790 -------------------
   791 
   792 * Significantly faster resolution;  
   793 
   794 * the different sections in a .thy file can now be mixed and repeated
   795 freely;
   796 
   797 * Database of theorems for FOL, HOL and ZF.  New
   798 commands including qed, qed_goal and bind_thm store theorems in the database.
   799 
   800 * Simple database queries: return a named theorem (get_thm) or all theorems of
   801 a given theory (thms_of), or find out what theory a theorem was proved in
   802 (theory_of_thm);
   803 
   804 * Bugs fixed in the inductive definition and datatype packages;
   805 
   806 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   807 and HOL_dup_cs obsolete;
   808 
   809 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   810 have been removed;
   811 
   812 * Simpler definition of function space in ZF;
   813 
   814 * new results about cardinal and ordinal arithmetic in ZF;
   815 
   816 * 'subtype' facility in HOL for introducing new types as subsets of existing
   817 types;
   818 
   819 
   820 $Id$