NEWS
author wenzelm
Mon Aug 24 15:52:39 1998 +0200 (1998-08-24)
changeset 5363 0cf15843b82f
parent 5332 cd53e59688a8
child 5373 57165d7271b5
permissions -rw-r--r--
isatool install;
     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: major changes to the inductive and datatype packages;
    13 
    14 * HOL: renamed r^-1 to 'converse' from 'inverse'; `inj_onto' is now
    15 called `inj_on';
    16 
    17 * HOL: removed duplicate thms in Arith:
    18   less_imp_add_less  should be replaced by  trans_less_add1
    19   le_imp_add_le      should be replaced by  trans_le_add1
    20 
    21 
    22 *** Proof tools ***
    23 
    24 * Simplifier: Asm_full_simp_tac is now more aggressive.
    25   1. It will sometimes reorient premises if that increases their power to
    26      simplify.
    27   2. It does no longer proceed strictly from left to right but may also
    28      rotate premises to achieve further simplification.
    29   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    30   old Asm_full_simp_tac in that it does not rotate premises.
    31 
    32 * Classical reasoner: wrapper mechanism for the classical reasoner now
    33 allows for selected deletion of wrappers, by introduction of names for
    34 wrapper functionals.  This implies that addbefore, addSbefore,
    35 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    36 and that adding two tactics with the same name overwrites the first
    37 one (emitting a warning).
    38   type wrapper = (int -> tactic) -> (int -> tactic)
    39   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    40   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    41   delWrapper, delSWrapper: claset *  string            -> claset
    42   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    43 
    44 * HOL/split_all_tac is now much faster and fails if there is nothing
    45 to split.  Existing (fragile) proofs may require adaption because the
    46 order and the names of the automatically generated variables have
    47 changed.  split_all_tac has moved within claset() from unsafe wrappers
    48 to safe wrappers, which means that !!-bound variables are split much
    49 more aggressively, and safe_tac and clarify_tac now split such
    50 variables.  If this splitting is not appropriate, use delSWrapper
    51 "split_all_tac".
    52 
    53 * HOL/Simplifier:
    54 
    55  - Rewrite rules for case distinctions can now be added permanently to
    56    the default simpset using Addsplits just like Addsimps. They can be
    57    removed via Delsplits just like Delsimps. Lower-case versions are
    58    also available.
    59 
    60  - The rule split_if is now part of the default simpset. This means
    61    that the simplifier will eliminate all occurrences of if-then-else
    62    in the conclusion of a goal. To prevent this, you can either remove
    63    split_if completely from the default simpset by `Delsplits
    64    [split_if]' or remove it in a specific call of the simplifier using
    65    `... delsplits [split_if]'.  You can also add/delete other case
    66    splitting rules to/from the default simpset: every datatype
    67    generates suitable rules `split_t_case' and `split_t_case_asm'
    68    (where t is the name of the datatype).
    69 
    70 * Classical reasoner - Simplifier combination: new force_tac (and
    71 derivatives Force_tac, force) combines rewriting and classical
    72 reasoning (and whatever other tools) similarly to auto_tac, but is
    73 aimed to solve the given subgoal completely;
    74 
    75 
    76 *** General ***
    77 
    78 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
    79 and `goalw': the theory is no longer needed as an explicit argument -
    80 the current theory context is used; assumptions are no longer returned
    81 at the ML-level unless one of them starts with ==> or !!; it is
    82 recommended to convert to these new commands using isatool fixgoal
    83 (backup your sources first!);
    84 
    85 * new top-level commands 'thm' and 'thms' for retrieving theorems from
    86 the current theory context, and 'theory' to lookup stored theories;
    87 
    88 * new theory section 'nonterminals' for purely syntactic types;
    89 
    90 * new theory section 'setup' for generic ML setup functions
    91 (e.g. package initialization);
    92 
    93 * the distribution now includes Isabelle icons: see
    94 lib/logo/isabelle-{small,tiny}.xpm;
    95 
    96 * isatool install - install binaries with absolute references to
    97 ISABELLE_HOME/bin;
    98 
    99 
   100 *** HOL ***
   101 
   102 * HOL/inductive package reorganized and improved: now supports mutual
   103 definitions such as
   104 
   105   inductive EVEN ODD
   106     intrs
   107       null "0 : EVEN"
   108       oddI "n : EVEN ==> Suc n : ODD"
   109       evenI "n : ODD ==> Suc n : EVEN"
   110 
   111 new theorem list "elims" contains an elimination rule for each of the
   112 recursive sets; inductive definitions now handle disjunctive premises
   113 correctly (also ZF);
   114 
   115 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   116 "mutual_induct" no longer exists - the induction rule is always
   117 contained in "induct";
   118 
   119 
   120 * HOL/datatype package re-implemented and greatly improved: now
   121 supports mutually recursive datatypes such as
   122 
   123   datatype
   124     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   125             | SUM ('a aexp) ('a aexp)
   126             | DIFF ('a aexp) ('a aexp)
   127             | NUM 'a
   128   and
   129     'a bexp = LESS ('a aexp) ('a aexp)
   130             | AND ('a bexp) ('a bexp)
   131             | OR ('a bexp) ('a bexp)
   132 
   133 as well as indirectly recursive datatypes such as
   134 
   135   datatype
   136     ('a, 'b) term = Var 'a
   137                   | App 'b ((('a, 'b) term) list)
   138 
   139 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   140 induction on mutually / indirectly recursive datatypes.
   141 
   142 Primrec equations are now stored in theory and can be accessed via
   143 <function_name>.simps.
   144 
   145 INCOMPATIBILITIES:
   146 
   147   - Theories using datatypes must now have theory Datatype as an
   148     ancestor.
   149   - The specific <typename>.induct_tac no longer exists - use the
   150     generic induct_tac instead.
   151   - natE has been renamed to nat.exhaust - use exhaust_tac
   152     instead of res_inst_tac ... natE. Note that the variable
   153     names in nat.exhaust differ from the names in natE, this
   154     may cause some "fragile" proofs to fail.
   155   - The theorems split_<typename>_case and split_<typename>_case_asm
   156     have been renamed to <typename>.split and <typename>.split_asm.
   157   - Since default sorts of type variables are now handled correctly,
   158     some datatype definitions may have to be annotated with explicit
   159     sort constraints.
   160   - Primrec definitions no longer require function name and type
   161     of recursive argument.
   162 
   163 Consider using isatool fixdatatype to adapt your theories and proof
   164 scripts to the new package (backup your sources first!).
   165 
   166 
   167 * HOL/record package: now includes concrete syntax for record types,
   168 terms, updates; still lacks important theorems, like surjective
   169 pairing and split;
   170 
   171 * reorganized the main HOL image: HOL/Integ and String loaded by
   172 default; theory Main includes everything;
   173 
   174 * added option_map_eq_Some to the default simpset claset;
   175 
   176 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   177 
   178 * many new identities for unions, intersections, set difference, etc.;
   179 
   180 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   181 called split_if, split_split, split_sum_case and split_nat_case (to go
   182 with add/delsplits);
   183 
   184 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   185 (?x::unit) = (); this is made part of the default simpset, which COULD
   186 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   187 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   188 unit_abs_eta_conv is added in order to counter the effect of
   189 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   190 %u.f();
   191 
   192 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   193 makes more sense);
   194 
   195 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name was misleading);
   196 
   197 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   198 to 'converse' from 'inverse' (for compatibility with ZF and some
   199 literature);
   200 
   201 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   202 the well-founded relation;
   203 
   204 * HOL/Update: new theory of function updates:
   205     f(a:=b) == %x. if x=a then b else f x
   206 may also be iterated as in f(a:=b,c:=d,...);
   207 
   208 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   209 
   210 * HOL/List:
   211   - new function list_update written xs[i:=v] that updates the i-th
   212     list position. May also be iterated as in xs[i:=a,j:=b,...].
   213   - new lexicographic orderings and corresponding wellfoundedness theorems.
   214 
   215 * HOL/Arith:
   216   - removed 'pred' (predecessor) function;
   217   - generalized some theorems about n-1;
   218   - many new laws about "div" and "mod";
   219   - new laws about greatest common divisors (see theory ex/Primes);
   220 
   221 * HOL/Relation: renamed the relational operator r^-1 "converse"
   222 instead of "inverse";
   223 
   224 * directory HOL/Real: a construction of the reals using Dedekind cuts
   225 (not included by default);
   226 
   227 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   228 
   229 * calling (stac rew i) now fails if "rew" has no effect on the goal
   230   [previously, this check worked only if the rewrite rule was unconditional]
   231   Now rew can involve either definitions or equalities (either == or =).
   232 
   233 
   234 *** ZF ***
   235 
   236 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   237   only the theorems proved on ZF.ML;
   238 
   239 * ZF INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name
   240   was misleading).  The rule and 'sym RS equals0E' are now in the default
   241   claset, giving automatic disjointness reasoning but breaking a few old 
   242   proofs.
   243 
   244 * ZF/Update: new theory of function updates
   245     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   246   may also be iterated as in f(a:=b,c:=d,...);
   247 
   248 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   249 
   250 * calling (stac rew i) now fails if "rew" has no effect on the goal
   251   [previously, this check worked only if the rewrite rule was unconditional]
   252   Now rew can involve either definitions or equalities (either == or =).
   253 
   254 * case_tac provided for compatibility with HOL
   255     (like the old excluded_middle_tac, but with subgoals swapped)
   256 
   257 
   258 *** Internal programming interfaces ***
   259 
   260 * Pure: several new basic modules made available for general use, see
   261 also src/Pure/README;
   262 
   263 * improved the theory data mechanism to support encapsulation (data
   264 kind name replaced by private Object.kind, acting as authorization
   265 key); new type-safe user interface via functor TheoryDataFun;
   266 
   267 * removed global_names compatibility flag -- all theory declarations
   268 are qualified by default;
   269 
   270 * module Pure/Syntax now offers quote / antiquote translation
   271 functions (useful for Hoare logic etc. with implicit dependencies);
   272 
   273 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   274 cterm -> thm;
   275 
   276 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   277 subgoal;
   278 
   279 * Display.print_goals function moved to Locale.print_goals;
   280 
   281 
   282 
   283 New in Isabelle98 (January 1998)
   284 --------------------------------
   285 
   286 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   287 
   288 * changed lexical syntax of terms / types: dots made part of long
   289 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   290 
   291 * simpset (and claset) reference variable replaced by functions
   292 simpset / simpset_ref;
   293 
   294 * no longer supports theory aliases (via merge) and non-trivial
   295 implicit merge of thms' signatures;
   296 
   297 * most internal names of constants changed due to qualified names;
   298 
   299 * changed Pure/Sequence interface (see Pure/seq.ML);
   300 
   301 
   302 *** General Changes ***
   303 
   304 * hierachically structured name spaces (for consts, types, axms, thms
   305 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   306 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   307 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   308 long_names for fully qualified output names; NOTE: ML programs
   309 (special tactics, packages etc.) referring to internal names may have
   310 to be adapted to cope with fully qualified names; in case of severe
   311 backward campatibility problems try setting 'global_names' at compile
   312 time to have enrything declared within a flat name space; one may also
   313 fine tune name declarations in theories via the 'global' and 'local'
   314 section;
   315 
   316 * reimplemented the implicit simpset and claset using the new anytype
   317 data filed in signatures; references simpset:simpset ref etc. are
   318 replaced by functions simpset:unit->simpset and
   319 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   320 to patch your ML files accordingly;
   321 
   322 * HTML output now includes theory graph data for display with Java
   323 applet or isatool browser; data generated automatically via isatool
   324 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   325 
   326 * defs may now be conditional; improved rewrite_goals_tac to handle
   327 conditional equations;
   328 
   329 * defs now admits additional type arguments, using TYPE('a) syntax;
   330 
   331 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   332 creates a new theory node; implicit merge of thms' signatures is
   333 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   334 transfer:theory->thm->thm in (rare) cases;
   335 
   336 * improved handling of draft signatures / theories; draft thms (and
   337 ctyps, cterms) are automatically promoted to real ones;
   338 
   339 * slightly changed interfaces for oracles: admit many per theory, named
   340 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   341 
   342 * print_goals: optional output of const types (set show_consts and
   343 show_types);
   344 
   345 * improved output of warnings (###) and errors (***);
   346 
   347 * subgoal_tac displays a warning if the new subgoal has type variables;
   348 
   349 * removed old README and Makefiles;
   350 
   351 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   352 
   353 * removed obsolete init_pps and init_database;
   354 
   355 * deleted the obsolete tactical STATE, which was declared by
   356     fun STATE tacfun st = tacfun st st;
   357 
   358 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   359 (which abbreviates $HOME);
   360 
   361 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   362 use isatool fixseq to adapt your ML programs (this works for fully
   363 qualified references to the Sequence structure only!);
   364 
   365 * use_thy no longer requires writable current directory; it always
   366 reloads .ML *and* .thy file, if either one is out of date;
   367 
   368 
   369 *** Classical Reasoner ***
   370 
   371 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   372 tactics that use classical reasoning to simplify a subgoal without
   373 splitting it into several subgoals;
   374 
   375 * Safe_tac: like safe_tac but uses the default claset;
   376 
   377 
   378 *** Simplifier ***
   379 
   380 * added simplification meta rules:
   381     (asm_)(full_)simplify: simpset -> thm -> thm;
   382 
   383 * simplifier.ML no longer part of Pure -- has to be loaded by object
   384 logics (again);
   385 
   386 * added prems argument to simplification procedures;
   387 
   388 * HOL, FOL, ZF: added infix function `addsplits':
   389   instead of `<simpset> setloop (split_tac <thms>)'
   390   you can simply write `<simpset> addsplits <thms>'
   391 
   392 
   393 *** Syntax ***
   394 
   395 * TYPE('a) syntax for type reflection terms;
   396 
   397 * no longer handles consts with name "" -- declare as 'syntax' instead;
   398 
   399 * pretty printer: changed order of mixfix annotation preference (again!);
   400 
   401 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   402 
   403 
   404 *** HOL ***
   405 
   406 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   407   with `addloop' of the simplifier to faciliate case splitting in premises.
   408 
   409 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   410 
   411 * HOL/Auth: new protocol proofs including some for the Internet
   412   protocol TLS;
   413 
   414 * HOL/Map: new theory of `maps' a la VDM;
   415 
   416 * HOL/simplifier: simplification procedures nat_cancel_sums for
   417 cancelling out common nat summands from =, <, <= (in)equalities, or
   418 differences; simplification procedures nat_cancel_factor for
   419 cancelling common factor from =, <, <= (in)equalities over natural
   420 sums; nat_cancel contains both kinds of procedures, it is installed by
   421 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   422 
   423 * HOL/simplifier: terms of the form
   424   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   425   are rewritten to
   426   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   427   and those of the form
   428   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   429   are rewritten to
   430   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   431 
   432 * HOL/datatype
   433   Each datatype `t' now comes with a theorem `split_t_case' of the form
   434 
   435   P(t_case f1 ... fn x) =
   436      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   437         ...
   438        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   439      )
   440 
   441   and a theorem `split_t_case_asm' of the form
   442 
   443   P(t_case f1 ... fn x) =
   444     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   445         ...
   446        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   447      )
   448   which can be added to a simpset via `addsplits'. The existing theorems
   449   expand_list_case and expand_option_case have been renamed to
   450   split_list_case and split_option_case.
   451 
   452 * HOL/Arithmetic:
   453   - `pred n' is automatically converted to `n-1'.
   454     Users are strongly encouraged not to use `pred' any longer,
   455     because it will disappear altogether at some point.
   456   - Users are strongly encouraged to write "0 < n" rather than
   457     "n ~= 0". Theorems and proof tools have been modified towards this
   458     `standard'.
   459 
   460 * HOL/Lists:
   461   the function "set_of_list" has been renamed "set" (and its theorems too);
   462   the function "nth" now takes its arguments in the reverse order and
   463   has acquired the infix notation "!" as in "xs!n".
   464 
   465 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   466 
   467 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   468   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   469 
   470 * HOL/record: extensible records with schematic structural subtyping
   471 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   472 still lacks various theorems and concrete record syntax;
   473 
   474 
   475 *** HOLCF ***
   476 
   477 * removed "axioms" and "generated by" sections;
   478 
   479 * replaced "ops" section by extended "consts" section, which is capable of
   480   handling the continuous function space "->" directly;
   481 
   482 * domain package:
   483   . proves theorems immediately and stores them in the theory,
   484   . creates hierachical name space,
   485   . now uses normal mixfix annotations (instead of cinfix...),
   486   . minor changes to some names and values (for consistency),
   487   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   488   . separator between mutual domain defs: changed "," to "and",
   489   . improved handling of sort constraints;  now they have to
   490     appear on the left-hand side of the equations only;
   491 
   492 * fixed LAM <x,y,zs>.b syntax;
   493 
   494 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   495 adm (%x. P (t x)), where P is chainfinite and t continuous;
   496 
   497 
   498 *** FOL and ZF ***
   499 
   500 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   501   with `addloop' of the simplifier to faciliate case splitting in premises.
   502 
   503 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   504 in HOL, they strip ALL and --> from proved theorems;
   505 
   506 
   507 
   508 New in Isabelle94-8 (May 1997)
   509 ------------------------------
   510 
   511 *** General Changes ***
   512 
   513 * new utilities to build / run / maintain Isabelle etc. (in parts
   514 still somewhat experimental); old Makefiles etc. still functional;
   515 
   516 * new 'Isabelle System Manual';
   517 
   518 * INSTALL text, together with ./configure and ./build scripts;
   519 
   520 * reimplemented type inference for greater efficiency, better error
   521 messages and clean internal interface;
   522 
   523 * prlim command for dealing with lots of subgoals (an easier way of
   524 setting goals_limit);
   525 
   526 
   527 *** Syntax ***
   528 
   529 * supports alternative (named) syntax tables (parser and pretty
   530 printer); internal interface is provided by add_modesyntax(_i);
   531 
   532 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   533 be used in conjunction with the Isabelle symbol font; uses the
   534 "symbols" syntax table;
   535 
   536 * added token_translation interface (may translate name tokens in
   537 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   538 the current print_mode); IMPORTANT: user print translation functions
   539 are responsible for marking newly introduced bounds
   540 (Syntax.mark_boundT);
   541 
   542 * token translations for modes "xterm" and "xterm_color" that display
   543 names in bold, underline etc. or colors (which requires a color
   544 version of xterm);
   545 
   546 * infixes may now be declared with names independent of their syntax;
   547 
   548 * added typed_print_translation (like print_translation, but may
   549 access type of constant);
   550 
   551 
   552 *** Classical Reasoner ***
   553 
   554 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   555 some limitations.  Blast_tac...
   556   + ignores addss, addbefore, addafter; this restriction is intrinsic
   557   + ignores elimination rules that don't have the correct format
   558 	(the conclusion MUST be a formula variable)
   559   + ignores types, which can make HOL proofs fail
   560   + rules must not require higher-order unification, e.g. apply_type in ZF
   561     [message "Function Var's argument not a bound variable" relates to this]
   562   + its proof strategy is more general but can actually be slower
   563 
   564 * substitution with equality assumptions no longer permutes other
   565 assumptions;
   566 
   567 * minor changes in semantics of addafter (now called addaltern); renamed
   568 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   569 (and access functions for it);
   570 
   571 * improved combination of classical reasoner and simplifier: 
   572   + functions for handling clasimpsets
   573   + improvement of addss: now the simplifier is called _after_ the
   574     safe steps.
   575   + safe variant of addss called addSss: uses safe simplifications
   576     _during_ the safe steps. It is more complete as it allows multiple 
   577     instantiations of unknowns (e.g. with slow_tac).
   578 
   579 *** Simplifier ***
   580 
   581 * added interface for simplification procedures (functions that
   582 produce *proven* rewrite rules on the fly, depending on current
   583 redex);
   584 
   585 * ordering on terms as parameter (used for ordered rewriting);
   586 
   587 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   588 
   589 * the solver is now split into a safe and an unsafe part.
   590 This should be invisible for the normal user, except that the
   591 functions setsolver and addsolver have been renamed to setSolver and
   592 addSolver; added safe_asm_full_simp_tac;
   593 
   594 
   595 *** HOL ***
   596 
   597 * a generic induction tactic `induct_tac' which works for all datatypes and
   598 also for type `nat';
   599 
   600 * a generic case distinction tactic `exhaust_tac' which works for all
   601 datatypes and also for type `nat';
   602 
   603 * each datatype comes with a function `size';
   604 
   605 * patterns in case expressions allow tuple patterns as arguments to
   606 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   607 
   608 * primrec now also works with type nat;
   609 
   610 * recdef: a new declaration form, allows general recursive functions to be
   611 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   612 
   613 * the constant for negation has been renamed from "not" to "Not" to
   614 harmonize with FOL, ZF, LK, etc.;
   615 
   616 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   617 infinite lists;
   618 
   619 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   620 
   621 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   622 problems in commutative rings, using axiomatic type classes for + and *;
   623 
   624 * more examples in HOL/MiniML and HOL/Auth;
   625 
   626 * more default rewrite rules for quantifiers, union/intersection;
   627 
   628 * a new constant `arbitrary == @x.False';
   629 
   630 * HOLCF/IOA replaces old HOL/IOA;
   631 
   632 * HOLCF changes: derived all rules and arities 
   633   + axiomatic type classes instead of classes 
   634   + typedef instead of faking type definitions
   635   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   636   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   637   + eliminated the types void, one, tr
   638   + use unit lift and bool lift (with translations) instead of one and tr
   639   + eliminated blift from Lift3.thy (use Def instead of blift)
   640   all eliminated rules are derived as theorems --> no visible changes ;
   641 
   642 
   643 *** ZF ***
   644 
   645 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   646 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   647 as ZF_cs addSIs [equalityI];
   648 
   649 
   650 
   651 New in Isabelle94-7 (November 96)
   652 ---------------------------------
   653 
   654 * allowing negative levels (as offsets) in prlev and choplev;
   655 
   656 * super-linear speedup for large simplifications;
   657 
   658 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   659 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   660 FAIL); can suppress it using the command Delsimps (ex_simps @
   661 all_simps); De Morgan laws are also now included, by default;
   662 
   663 * improved printing of ==>  :  ~:
   664 
   665 * new object-logic "Sequents" adds linear logic, while replacing LK
   666 and Modal (thanks to Sara Kalvala);
   667 
   668 * HOL/Auth: correctness proofs for authentication protocols;
   669 
   670 * HOL: new auto_tac combines rewriting and classical reasoning (many
   671 examples on HOL/Auth);
   672 
   673 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   674 the rewriter and classical reasoner simultaneously;
   675 
   676 * function uresult no longer returns theorems in "standard" format;
   677 regain previous version by: val uresult = standard o uresult;
   678 
   679 
   680 
   681 New in Isabelle94-6
   682 -------------------
   683 
   684 * oracles -- these establish an interface between Isabelle and trusted
   685 external reasoners, which may deliver results as theorems;
   686 
   687 * proof objects (in particular record all uses of oracles);
   688 
   689 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   690 
   691 * "constdefs" section in theory files;
   692 
   693 * "primrec" section (HOL) no longer requires names;
   694 
   695 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   696 
   697 
   698 
   699 New in Isabelle94-5
   700 -------------------
   701 
   702 * reduced space requirements;
   703 
   704 * automatic HTML generation from theories;
   705 
   706 * theory files no longer require "..." (quotes) around most types;
   707 
   708 * new examples, including two proofs of the Church-Rosser theorem;
   709 
   710 * non-curried (1994) version of HOL is no longer distributed;
   711 
   712 
   713 
   714 New in Isabelle94-4
   715 -------------------
   716 
   717 * greatly reduced space requirements;
   718 
   719 * theory files (.thy) no longer require \...\ escapes at line breaks;
   720 
   721 * searchable theorem database (see the section "Retrieving theorems" on 
   722 page 8 of the Reference Manual);
   723 
   724 * new examples, including Grabczewski's monumental case study of the
   725 Axiom of Choice;
   726 
   727 * The previous version of HOL renamed to Old_HOL;
   728 
   729 * The new version of HOL (previously called CHOL) uses a curried syntax 
   730 for functions.  Application looks like f a b instead of f(a,b);
   731 
   732 * Mutually recursive inductive definitions finally work in HOL;
   733 
   734 * In ZF, pattern-matching on tuples is now available in all abstractions and
   735 translates to the operator "split";
   736 
   737 
   738 
   739 New in Isabelle94-3
   740 -------------------
   741 
   742 * new infix operator, addss, allowing the classical reasoner to 
   743 perform simplification at each step of its search.  Example:
   744 	fast_tac (cs addss ss)
   745 
   746 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   747 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   748 look like (a,b) instead of <a,b>;
   749 
   750 * PLEASE NOTE: CHOL will eventually replace HOL!
   751 
   752 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   753 It translates to the operator "split".  A new theory of integers is available;
   754 
   755 * In ZF, integer numerals now denote two's-complement binary integers.
   756 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   757 
   758 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   759 of the Axiom of Choice;
   760 
   761 
   762 
   763 New in Isabelle94-2
   764 -------------------
   765 
   766 * Significantly faster resolution;  
   767 
   768 * the different sections in a .thy file can now be mixed and repeated
   769 freely;
   770 
   771 * Database of theorems for FOL, HOL and ZF.  New
   772 commands including qed, qed_goal and bind_thm store theorems in the database.
   773 
   774 * Simple database queries: return a named theorem (get_thm) or all theorems of
   775 a given theory (thms_of), or find out what theory a theorem was proved in
   776 (theory_of_thm);
   777 
   778 * Bugs fixed in the inductive definition and datatype packages;
   779 
   780 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   781 and HOL_dup_cs obsolete;
   782 
   783 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   784 have been removed;
   785 
   786 * Simpler definition of function space in ZF;
   787 
   788 * new results about cardinal and ordinal arithmetic in ZF;
   789 
   790 * 'subtype' facility in HOL for introducing new types as subsets of existing
   791 types;
   792 
   793 
   794 $Id$