NEWS
author nipkow
Fri Oct 16 08:48:05 1998 +0200 (1998-10-16)
changeset 5651 ca45d6126c8a
parent 5650 38bda28c68a2
child 5657 1a6c9c6a3f8e
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 * HOL and ZF: unary minus for integers is now #- instead of #~.  In ZF, 
    26   expressions such as n#-1 must be changed to n#- 1, since #-1 is now taken
    27   as an integer constant.
    28 
    29 * Pure: ML function 'theory_of' replaced by 'theory';
    30 
    31 
    32 *** Proof tools ***
    33 
    34 * Simplifier: Asm_full_simp_tac is now more aggressive.
    35   1. It will sometimes reorient premises if that increases their power to
    36      simplify.
    37   2. It does no longer proceed strictly from left to right but may also
    38      rotate premises to achieve further simplification.
    39   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    40   old Asm_full_simp_tac in that it does not rotate premises.
    41 
    42 * Classical reasoner: wrapper mechanism for the classical reasoner now
    43 allows for selected deletion of wrappers, by introduction of names for
    44 wrapper functionals.  This implies that addbefore, addSbefore,
    45 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    46 and that adding two tactics with the same name overwrites the first
    47 one (emitting a warning).
    48   type wrapper = (int -> tactic) -> (int -> tactic)
    49   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    50   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    51   delWrapper, delSWrapper: claset *  string            -> claset
    52   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    53 
    54 * Classical reasoner: addbefore / addSbefore now have APPEND / ORELSE semantics;
    55   addbefore now affects only the unsafe part of step_tac etc.;
    56   This affects addss/auto_tac/force_tac, so EXISTING (INSTABLE) PROOFS MAY FAIL, but
    57   most proofs should be fixable easily, e.g. by replacing Auto_tac by Force_tac.
    58 
    59 * Classical reasoner: setwrapper to setWrapper and compwrapper to compWrapper; 
    60   added safe wrapper (and access functions for it);
    61 
    62 * HOL/split_all_tac is now much faster and fails if there is nothing
    63 to split.  Existing (fragile) proofs may require adaption because the
    64 order and the names of the automatically generated variables have
    65 changed.  split_all_tac has moved within claset() from unsafe wrappers
    66 to safe wrappers, which means that !!-bound variables are split much
    67 more aggressively, and safe_tac and clarify_tac now split such
    68 variables.  If this splitting is not appropriate, use delSWrapper
    69 "split_all_tac".
    70 
    71 * HOL/Simplifier:
    72 
    73  - Rewrite rules for case distinctions can now be added permanently to
    74    the default simpset using Addsplits just like Addsimps. They can be
    75    removed via Delsplits just like Delsimps. Lower-case versions are
    76    also available.
    77 
    78  - The rule split_if is now part of the default simpset. This means
    79    that the simplifier will eliminate all occurrences of if-then-else
    80    in the conclusion of a goal. To prevent this, you can either remove
    81    split_if completely from the default simpset by `Delsplits
    82    [split_if]' or remove it in a specific call of the simplifier using
    83    `... delsplits [split_if]'.  You can also add/delete other case
    84    splitting rules to/from the default simpset: every datatype
    85    generates suitable rules `split_t_case' and `split_t_case_asm'
    86    (where t is the name of the datatype).
    87 
    88 * Classical reasoner - Simplifier combination: new force_tac (and
    89 derivatives Force_tac, force) combines rewriting and classical
    90 reasoning (and whatever other tools) similarly to auto_tac, but is
    91 aimed to solve the given subgoal completely;
    92 
    93 
    94 *** General ***
    95 
    96 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
    97 and `goalw': the theory is no longer needed as an explicit argument -
    98 the current theory context is used; assumptions are no longer returned
    99 at the ML-level unless one of them starts with ==> or !!; it is
   100 recommended to convert to these new commands using isatool fixgoal
   101 (backup your sources first!);
   102 
   103 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   104 the current theory context, and 'theory' to lookup stored theories;
   105 
   106 * new theory section 'nonterminals' for purely syntactic types;
   107 
   108 * new theory section 'setup' for generic ML setup functions
   109 (e.g. package initialization);
   110 
   111 * the distribution now includes Isabelle icons: see
   112 lib/logo/isabelle-{small,tiny}.xpm;
   113 
   114 * isatool install - install binaries with absolute references to
   115 ISABELLE_HOME/bin;
   116 
   117 * isatool logo -- create instances of the Isabelle logo (as EPS);
   118 
   119 * print mode 'emacs' reserved for Isamode;
   120 
   121 
   122 *** HOL ***
   123 
   124 * HOL/inductive package reorganized and improved: now supports mutual
   125 definitions such as
   126 
   127   inductive EVEN ODD
   128     intrs
   129       null "0 : EVEN"
   130       oddI "n : EVEN ==> Suc n : ODD"
   131       evenI "n : ODD ==> Suc n : EVEN"
   132 
   133 new theorem list "elims" contains an elimination rule for each of the
   134 recursive sets; inductive definitions now handle disjunctive premises
   135 correctly (also ZF);
   136 
   137 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   138 "mutual_induct" no longer exists - the induction rule is always
   139 contained in "induct";
   140 
   141 
   142 * HOL/datatype package re-implemented and greatly improved: now
   143 supports mutually recursive datatypes such as
   144 
   145   datatype
   146     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   147             | SUM ('a aexp) ('a aexp)
   148             | DIFF ('a aexp) ('a aexp)
   149             | NUM 'a
   150   and
   151     'a bexp = LESS ('a aexp) ('a aexp)
   152             | AND ('a bexp) ('a bexp)
   153             | OR ('a bexp) ('a bexp)
   154 
   155 as well as indirectly recursive datatypes such as
   156 
   157   datatype
   158     ('a, 'b) term = Var 'a
   159                   | App 'b ((('a, 'b) term) list)
   160 
   161 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   162 induction on mutually / indirectly recursive datatypes.
   163 
   164 Primrec equations are now stored in theory and can be accessed via
   165 <function_name>.simps.
   166 
   167 INCOMPATIBILITIES:
   168 
   169   - Theories using datatypes must now have theory Datatype as an
   170     ancestor.
   171   - The specific <typename>.induct_tac no longer exists - use the
   172     generic induct_tac instead.
   173   - natE has been renamed to nat.exhaust - use exhaust_tac
   174     instead of res_inst_tac ... natE. Note that the variable
   175     names in nat.exhaust differ from the names in natE, this
   176     may cause some "fragile" proofs to fail.
   177   - The theorems split_<typename>_case and split_<typename>_case_asm
   178     have been renamed to <typename>.split and <typename>.split_asm.
   179   - Since default sorts of type variables are now handled correctly,
   180     some datatype definitions may have to be annotated with explicit
   181     sort constraints.
   182   - Primrec definitions no longer require function name and type
   183     of recursive argument.
   184 
   185 Consider using isatool fixdatatype to adapt your theories and proof
   186 scripts to the new package (backup your sources first!).
   187 
   188 
   189 * HOL/record package: now includes concrete syntax for record types,
   190 terms, updates; still lacks important theorems, like surjective
   191 pairing and split;
   192 
   193 * reorganized the main HOL image: HOL/Integ and String loaded by
   194 default; theory Main includes everything;
   195 
   196 * automatic simplification of integer sums and comparisons, using cancellation;
   197 
   198 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   199 
   200 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   201 
   202 * many new identities for unions, intersections, set difference, etc.;
   203 
   204 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   205 called split_if, split_split, split_sum_case and split_nat_case (to go
   206 with add/delsplits);
   207 
   208 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   209 (?x::unit) = (); this is made part of the default simpset, which COULD
   210 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   211 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   212 unit_abs_eta_conv is added in order to counter the effect of
   213 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   214 %u.f();
   215 
   216 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   217 makes more sense);
   218 
   219 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   220   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   221   disjointness reasoning but breaking a few old proofs.
   222 
   223 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   224 to 'converse' from 'inverse' (for compatibility with ZF and some
   225 literature);
   226 
   227 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   228 the well-founded relation;
   229 
   230 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   231     Compl A.  The "Compl" syntax remains available as input syntax for this
   232     release ONLY.
   233 
   234 * HOL/Update: new theory of function updates:
   235     f(a:=b) == %x. if x=a then b else f x
   236 may also be iterated as in f(a:=b,c:=d,...);
   237 
   238 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   239 
   240 * HOL/List:
   241   - new function list_update written xs[i:=v] that updates the i-th
   242     list position. May also be iterated as in xs[i:=a,j:=b,...].
   243   - new function `upt' written [i..j(] which generates the list
   244     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   245     bound write [i..j], which is a shorthand for [i..j+1(].
   246   - new lexicographic orderings and corresponding wellfoundedness theorems.
   247 
   248 * HOL/Arith:
   249   - removed 'pred' (predecessor) function;
   250   - generalized some theorems about n-1;
   251   - many new laws about "div" and "mod";
   252   - new laws about greatest common divisors (see theory ex/Primes);
   253 
   254 * HOL/Relation: renamed the relational operator r^-1 "converse"
   255 instead of "inverse";
   256 
   257 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   258   of the multiset ordering;
   259 
   260 * directory HOL/Real: a construction of the reals using Dedekind cuts
   261   (not included by default);
   262 
   263 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   264 
   265 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   266   programs, i.e. different program variables may have different types.
   267 
   268 * calling (stac rew i) now fails if "rew" has no effect on the goal
   269   [previously, this check worked only if the rewrite rule was unconditional]
   270   Now rew can involve either definitions or equalities (either == or =).
   271 
   272 
   273 *** ZF ***
   274 
   275 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   276   only the theorems proved on ZF.ML;
   277 
   278 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   279   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   280   disjointness reasoning but breaking a few old proofs.
   281 
   282 * ZF/Update: new theory of function updates
   283     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   284   may also be iterated as in f(a:=b,c:=d,...);
   285 
   286 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   287 
   288 * calling (stac rew i) now fails if "rew" has no effect on the goal
   289   [previously, this check worked only if the rewrite rule was unconditional]
   290   Now rew can involve either definitions or equalities (either == or =).
   291 
   292 * case_tac provided for compatibility with HOL
   293     (like the old excluded_middle_tac, but with subgoals swapped)
   294 
   295 
   296 *** Internal programming interfaces ***
   297 
   298 * Pure: several new basic modules made available for general use, see
   299 also src/Pure/README;
   300 
   301 * improved the theory data mechanism to support encapsulation (data
   302 kind name replaced by private Object.kind, acting as authorization
   303 key); new type-safe user interface via functor TheoryDataFun; generic
   304 print_data function becomes basically useless;
   305 
   306 * removed global_names compatibility flag -- all theory declarations
   307 are qualified by default;
   308 
   309 * module Pure/Syntax now offers quote / antiquote translation
   310 functions (useful for Hoare logic etc. with implicit dependencies);
   311 see HOL/ex/Antiquote for an example use;
   312 
   313 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   314 cterm -> thm;
   315 
   316 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   317 subgoal;
   318 
   319 * Display.print_goals function moved to Locale.print_goals;
   320 
   321 
   322 
   323 New in Isabelle98 (January 1998)
   324 --------------------------------
   325 
   326 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   327 
   328 * changed lexical syntax of terms / types: dots made part of long
   329 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   330 
   331 * simpset (and claset) reference variable replaced by functions
   332 simpset / simpset_ref;
   333 
   334 * no longer supports theory aliases (via merge) and non-trivial
   335 implicit merge of thms' signatures;
   336 
   337 * most internal names of constants changed due to qualified names;
   338 
   339 * changed Pure/Sequence interface (see Pure/seq.ML);
   340 
   341 
   342 *** General Changes ***
   343 
   344 * hierachically structured name spaces (for consts, types, axms, thms
   345 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   346 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   347 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   348 long_names for fully qualified output names; NOTE: ML programs
   349 (special tactics, packages etc.) referring to internal names may have
   350 to be adapted to cope with fully qualified names; in case of severe
   351 backward campatibility problems try setting 'global_names' at compile
   352 time to have enrything declared within a flat name space; one may also
   353 fine tune name declarations in theories via the 'global' and 'local'
   354 section;
   355 
   356 * reimplemented the implicit simpset and claset using the new anytype
   357 data filed in signatures; references simpset:simpset ref etc. are
   358 replaced by functions simpset:unit->simpset and
   359 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   360 to patch your ML files accordingly;
   361 
   362 * HTML output now includes theory graph data for display with Java
   363 applet or isatool browser; data generated automatically via isatool
   364 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   365 
   366 * defs may now be conditional; improved rewrite_goals_tac to handle
   367 conditional equations;
   368 
   369 * defs now admits additional type arguments, using TYPE('a) syntax;
   370 
   371 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   372 creates a new theory node; implicit merge of thms' signatures is
   373 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   374 transfer:theory->thm->thm in (rare) cases;
   375 
   376 * improved handling of draft signatures / theories; draft thms (and
   377 ctyps, cterms) are automatically promoted to real ones;
   378 
   379 * slightly changed interfaces for oracles: admit many per theory, named
   380 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   381 
   382 * print_goals: optional output of const types (set show_consts and
   383 show_types);
   384 
   385 * improved output of warnings (###) and errors (***);
   386 
   387 * subgoal_tac displays a warning if the new subgoal has type variables;
   388 
   389 * removed old README and Makefiles;
   390 
   391 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   392 
   393 * removed obsolete init_pps and init_database;
   394 
   395 * deleted the obsolete tactical STATE, which was declared by
   396     fun STATE tacfun st = tacfun st st;
   397 
   398 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   399 (which abbreviates $HOME);
   400 
   401 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   402 use isatool fixseq to adapt your ML programs (this works for fully
   403 qualified references to the Sequence structure only!);
   404 
   405 * use_thy no longer requires writable current directory; it always
   406 reloads .ML *and* .thy file, if either one is out of date;
   407 
   408 
   409 *** Classical Reasoner ***
   410 
   411 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   412 tactics that use classical reasoning to simplify a subgoal without
   413 splitting it into several subgoals;
   414 
   415 * Safe_tac: like safe_tac but uses the default claset;
   416 
   417 
   418 *** Simplifier ***
   419 
   420 * added simplification meta rules:
   421     (asm_)(full_)simplify: simpset -> thm -> thm;
   422 
   423 * simplifier.ML no longer part of Pure -- has to be loaded by object
   424 logics (again);
   425 
   426 * added prems argument to simplification procedures;
   427 
   428 * HOL, FOL, ZF: added infix function `addsplits':
   429   instead of `<simpset> setloop (split_tac <thms>)'
   430   you can simply write `<simpset> addsplits <thms>'
   431 
   432 
   433 *** Syntax ***
   434 
   435 * TYPE('a) syntax for type reflection terms;
   436 
   437 * no longer handles consts with name "" -- declare as 'syntax' instead;
   438 
   439 * pretty printer: changed order of mixfix annotation preference (again!);
   440 
   441 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   442 
   443 
   444 *** HOL ***
   445 
   446 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   447   with `addloop' of the simplifier to faciliate case splitting in premises.
   448 
   449 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   450 
   451 * HOL/Auth: new protocol proofs including some for the Internet
   452   protocol TLS;
   453 
   454 * HOL/Map: new theory of `maps' a la VDM;
   455 
   456 * HOL/simplifier: simplification procedures nat_cancel_sums for
   457 cancelling out common nat summands from =, <, <= (in)equalities, or
   458 differences; simplification procedures nat_cancel_factor for
   459 cancelling common factor from =, <, <= (in)equalities over natural
   460 sums; nat_cancel contains both kinds of procedures, it is installed by
   461 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   462 
   463 * HOL/simplifier: terms of the form
   464   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   465   are rewritten to
   466   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   467   and those of the form
   468   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   469   are rewritten to
   470   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   471 
   472 * HOL/datatype
   473   Each datatype `t' now comes with a theorem `split_t_case' of the form
   474 
   475   P(t_case f1 ... fn x) =
   476      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   477         ...
   478        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   479      )
   480 
   481   and a theorem `split_t_case_asm' of the form
   482 
   483   P(t_case f1 ... fn x) =
   484     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   485         ...
   486        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   487      )
   488   which can be added to a simpset via `addsplits'. The existing theorems
   489   expand_list_case and expand_option_case have been renamed to
   490   split_list_case and split_option_case.
   491 
   492 * HOL/Arithmetic:
   493   - `pred n' is automatically converted to `n-1'.
   494     Users are strongly encouraged not to use `pred' any longer,
   495     because it will disappear altogether at some point.
   496   - Users are strongly encouraged to write "0 < n" rather than
   497     "n ~= 0". Theorems and proof tools have been modified towards this
   498     `standard'.
   499 
   500 * HOL/Lists:
   501   the function "set_of_list" has been renamed "set" (and its theorems too);
   502   the function "nth" now takes its arguments in the reverse order and
   503   has acquired the infix notation "!" as in "xs!n".
   504 
   505 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   506 
   507 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   508   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   509 
   510 * HOL/record: extensible records with schematic structural subtyping
   511 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   512 still lacks various theorems and concrete record syntax;
   513 
   514 
   515 *** HOLCF ***
   516 
   517 * removed "axioms" and "generated by" sections;
   518 
   519 * replaced "ops" section by extended "consts" section, which is capable of
   520   handling the continuous function space "->" directly;
   521 
   522 * domain package:
   523   . proves theorems immediately and stores them in the theory,
   524   . creates hierachical name space,
   525   . now uses normal mixfix annotations (instead of cinfix...),
   526   . minor changes to some names and values (for consistency),
   527   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   528   . separator between mutual domain defs: changed "," to "and",
   529   . improved handling of sort constraints;  now they have to
   530     appear on the left-hand side of the equations only;
   531 
   532 * fixed LAM <x,y,zs>.b syntax;
   533 
   534 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   535 adm (%x. P (t x)), where P is chainfinite and t continuous;
   536 
   537 
   538 *** FOL and ZF ***
   539 
   540 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   541   with `addloop' of the simplifier to faciliate case splitting in premises.
   542 
   543 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   544 in HOL, they strip ALL and --> from proved theorems;
   545 
   546 
   547 
   548 New in Isabelle94-8 (May 1997)
   549 ------------------------------
   550 
   551 *** General Changes ***
   552 
   553 * new utilities to build / run / maintain Isabelle etc. (in parts
   554 still somewhat experimental); old Makefiles etc. still functional;
   555 
   556 * new 'Isabelle System Manual';
   557 
   558 * INSTALL text, together with ./configure and ./build scripts;
   559 
   560 * reimplemented type inference for greater efficiency, better error
   561 messages and clean internal interface;
   562 
   563 * prlim command for dealing with lots of subgoals (an easier way of
   564 setting goals_limit);
   565 
   566 
   567 *** Syntax ***
   568 
   569 * supports alternative (named) syntax tables (parser and pretty
   570 printer); internal interface is provided by add_modesyntax(_i);
   571 
   572 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   573 be used in conjunction with the Isabelle symbol font; uses the
   574 "symbols" syntax table;
   575 
   576 * added token_translation interface (may translate name tokens in
   577 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   578 the current print_mode); IMPORTANT: user print translation functions
   579 are responsible for marking newly introduced bounds
   580 (Syntax.mark_boundT);
   581 
   582 * token translations for modes "xterm" and "xterm_color" that display
   583 names in bold, underline etc. or colors (which requires a color
   584 version of xterm);
   585 
   586 * infixes may now be declared with names independent of their syntax;
   587 
   588 * added typed_print_translation (like print_translation, but may
   589 access type of constant);
   590 
   591 
   592 *** Classical Reasoner ***
   593 
   594 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   595 some limitations.  Blast_tac...
   596   + ignores addss, addbefore, addafter; this restriction is intrinsic
   597   + ignores elimination rules that don't have the correct format
   598 	(the conclusion MUST be a formula variable)
   599   + ignores types, which can make HOL proofs fail
   600   + rules must not require higher-order unification, e.g. apply_type in ZF
   601     [message "Function Var's argument not a bound variable" relates to this]
   602   + its proof strategy is more general but can actually be slower
   603 
   604 * substitution with equality assumptions no longer permutes other
   605 assumptions;
   606 
   607 * minor changes in semantics of addafter (now called addaltern); renamed
   608 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   609 (and access functions for it);
   610 
   611 * improved combination of classical reasoner and simplifier: 
   612   + functions for handling clasimpsets
   613   + improvement of addss: now the simplifier is called _after_ the
   614     safe steps.
   615   + safe variant of addss called addSss: uses safe simplifications
   616     _during_ the safe steps. It is more complete as it allows multiple 
   617     instantiations of unknowns (e.g. with slow_tac).
   618 
   619 *** Simplifier ***
   620 
   621 * added interface for simplification procedures (functions that
   622 produce *proven* rewrite rules on the fly, depending on current
   623 redex);
   624 
   625 * ordering on terms as parameter (used for ordered rewriting);
   626 
   627 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   628 
   629 * the solver is now split into a safe and an unsafe part.
   630 This should be invisible for the normal user, except that the
   631 functions setsolver and addsolver have been renamed to setSolver and
   632 addSolver; added safe_asm_full_simp_tac;
   633 
   634 
   635 *** HOL ***
   636 
   637 * a generic induction tactic `induct_tac' which works for all datatypes and
   638 also for type `nat';
   639 
   640 * a generic case distinction tactic `exhaust_tac' which works for all
   641 datatypes and also for type `nat';
   642 
   643 * each datatype comes with a function `size';
   644 
   645 * patterns in case expressions allow tuple patterns as arguments to
   646 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   647 
   648 * primrec now also works with type nat;
   649 
   650 * recdef: a new declaration form, allows general recursive functions to be
   651 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   652 
   653 * the constant for negation has been renamed from "not" to "Not" to
   654 harmonize with FOL, ZF, LK, etc.;
   655 
   656 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   657 infinite lists;
   658 
   659 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   660 
   661 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   662 problems in commutative rings, using axiomatic type classes for + and *;
   663 
   664 * more examples in HOL/MiniML and HOL/Auth;
   665 
   666 * more default rewrite rules for quantifiers, union/intersection;
   667 
   668 * a new constant `arbitrary == @x.False';
   669 
   670 * HOLCF/IOA replaces old HOL/IOA;
   671 
   672 * HOLCF changes: derived all rules and arities 
   673   + axiomatic type classes instead of classes 
   674   + typedef instead of faking type definitions
   675   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   676   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   677   + eliminated the types void, one, tr
   678   + use unit lift and bool lift (with translations) instead of one and tr
   679   + eliminated blift from Lift3.thy (use Def instead of blift)
   680   all eliminated rules are derived as theorems --> no visible changes ;
   681 
   682 
   683 *** ZF ***
   684 
   685 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   686 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   687 as ZF_cs addSIs [equalityI];
   688 
   689 
   690 
   691 New in Isabelle94-7 (November 96)
   692 ---------------------------------
   693 
   694 * allowing negative levels (as offsets) in prlev and choplev;
   695 
   696 * super-linear speedup for large simplifications;
   697 
   698 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   699 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   700 FAIL); can suppress it using the command Delsimps (ex_simps @
   701 all_simps); De Morgan laws are also now included, by default;
   702 
   703 * improved printing of ==>  :  ~:
   704 
   705 * new object-logic "Sequents" adds linear logic, while replacing LK
   706 and Modal (thanks to Sara Kalvala);
   707 
   708 * HOL/Auth: correctness proofs for authentication protocols;
   709 
   710 * HOL: new auto_tac combines rewriting and classical reasoning (many
   711 examples on HOL/Auth);
   712 
   713 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   714 the rewriter and classical reasoner simultaneously;
   715 
   716 * function uresult no longer returns theorems in "standard" format;
   717 regain previous version by: val uresult = standard o uresult;
   718 
   719 
   720 
   721 New in Isabelle94-6
   722 -------------------
   723 
   724 * oracles -- these establish an interface between Isabelle and trusted
   725 external reasoners, which may deliver results as theorems;
   726 
   727 * proof objects (in particular record all uses of oracles);
   728 
   729 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   730 
   731 * "constdefs" section in theory files;
   732 
   733 * "primrec" section (HOL) no longer requires names;
   734 
   735 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   736 
   737 
   738 
   739 New in Isabelle94-5
   740 -------------------
   741 
   742 * reduced space requirements;
   743 
   744 * automatic HTML generation from theories;
   745 
   746 * theory files no longer require "..." (quotes) around most types;
   747 
   748 * new examples, including two proofs of the Church-Rosser theorem;
   749 
   750 * non-curried (1994) version of HOL is no longer distributed;
   751 
   752 
   753 
   754 New in Isabelle94-4
   755 -------------------
   756 
   757 * greatly reduced space requirements;
   758 
   759 * theory files (.thy) no longer require \...\ escapes at line breaks;
   760 
   761 * searchable theorem database (see the section "Retrieving theorems" on 
   762 page 8 of the Reference Manual);
   763 
   764 * new examples, including Grabczewski's monumental case study of the
   765 Axiom of Choice;
   766 
   767 * The previous version of HOL renamed to Old_HOL;
   768 
   769 * The new version of HOL (previously called CHOL) uses a curried syntax 
   770 for functions.  Application looks like f a b instead of f(a,b);
   771 
   772 * Mutually recursive inductive definitions finally work in HOL;
   773 
   774 * In ZF, pattern-matching on tuples is now available in all abstractions and
   775 translates to the operator "split";
   776 
   777 
   778 
   779 New in Isabelle94-3
   780 -------------------
   781 
   782 * new infix operator, addss, allowing the classical reasoner to 
   783 perform simplification at each step of its search.  Example:
   784 	fast_tac (cs addss ss)
   785 
   786 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   787 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   788 look like (a,b) instead of <a,b>;
   789 
   790 * PLEASE NOTE: CHOL will eventually replace HOL!
   791 
   792 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   793 It translates to the operator "split".  A new theory of integers is available;
   794 
   795 * In ZF, integer numerals now denote two's-complement binary integers.
   796 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   797 
   798 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   799 of the Axiom of Choice;
   800 
   801 
   802 
   803 New in Isabelle94-2
   804 -------------------
   805 
   806 * Significantly faster resolution;  
   807 
   808 * the different sections in a .thy file can now be mixed and repeated
   809 freely;
   810 
   811 * Database of theorems for FOL, HOL and ZF.  New
   812 commands including qed, qed_goal and bind_thm store theorems in the database.
   813 
   814 * Simple database queries: return a named theorem (get_thm) or all theorems of
   815 a given theory (thms_of), or find out what theory a theorem was proved in
   816 (theory_of_thm);
   817 
   818 * Bugs fixed in the inductive definition and datatype packages;
   819 
   820 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   821 and HOL_dup_cs obsolete;
   822 
   823 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   824 have been removed;
   825 
   826 * Simpler definition of function space in ZF;
   827 
   828 * new results about cardinal and ordinal arithmetic in ZF;
   829 
   830 * 'subtype' facility in HOL for introducing new types as subsets of existing
   831 types;
   832 
   833 
   834 $Id$