NEWS
author wenzelm
Thu Oct 22 12:26:55 1998 +0200 (1998-10-22)
changeset 5726 5de7e399ec88
parent 5722 c669e2161b08
child 5731 f84dc3b811e9
permissions -rw-r--r--
tuned;
record package;
     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 automated proof tools;
    11 
    12 * HOL: major changes to the inductive and datatype packages, including
    13 some minor incompatibilities of theory syntax;
    14 
    15 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
    16 called `inj_on';
    17 
    18 * HOL: removed duplicate thms in Arith:
    19   less_imp_add_less  should be replaced by  trans_less_add1
    20   le_imp_add_le      should be replaced by  trans_le_add1
    21 
    22 * HOL: unary minus is now overloaded (new type constraints may be
    23 required);
    24 
    25 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
    26 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
    27 now taken as an integer constant.
    28 
    29 * Pure: ML function 'theory_of' renamed to 'theory';
    30 
    31 
    32 *** Proof tools ***
    33 
    34 * Simplifier:
    35   1. Asm_full_simp_tac is now more aggressive.
    36      1. It will sometimes reorient premises if that increases their power to
    37         simplify.
    38      2. It does no longer proceed strictly from left to right but may also
    39         rotate premises to achieve further simplification.
    40      For compatibility reasons there is now Asm_lr_simp_tac which is like the
    41      old Asm_full_simp_tac in that it does not rotate premises.
    42   2. The simplifier now knows a little bit about nat-arithmetic.
    43 
    44 * Classical reasoner: wrapper mechanism for the classical reasoner now
    45 allows for selected deletion of wrappers, by introduction of names for
    46 wrapper functionals.  This implies that addbefore, addSbefore,
    47 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    48 and that adding two tactics with the same name overwrites the first
    49 one (emitting a warning).
    50   type wrapper = (int -> tactic) -> (int -> tactic)
    51   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    52   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    53   delWrapper, delSWrapper: claset *  string            -> claset
    54   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    55 
    56 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
    57 semantics; addbefore now affects only the unsafe part of step_tac
    58 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
    59 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
    60 by Force_tac;
    61 
    62 * Classical reasoner: setwrapper to setWrapper and compwrapper to
    63 compWrapper; added safe wrapper (and access functions for it);
    64 
    65 * HOL/split_all_tac is now much faster and fails if there is nothing
    66 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
    67 and the names of the automatically generated variables have changed.
    68 split_all_tac has moved within claset() from unsafe wrappers to safe
    69 wrappers, which means that !!-bound variables are split much more
    70 aggressively, and safe_tac and clarify_tac now split such variables.
    71 If this splitting is not appropriate, use delSWrapper "split_all_tac".
    72 Note: the same holds for record_split_tac, which does the job of
    73 split_all_tac for record fields.
    74 
    75 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
    76 permanently to the default simpset using Addsplits just like
    77 Addsimps. They can be removed via Delsplits just like
    78 Delsimps. Lower-case versions are also available.
    79 
    80 * HOL/Simplifier: The rule split_if is now part of the default
    81 simpset. This means that the simplifier will eliminate all occurrences
    82 of if-then-else in the conclusion of a goal. To prevent this, you can
    83 either remove split_if completely from the default simpset by
    84 `Delsplits [split_if]' or remove it in a specific call of the
    85 simplifier using `... delsplits [split_if]'.  You can also add/delete
    86 other case splitting rules to/from the default simpset: every datatype
    87 generates suitable rules `split_t_case' and `split_t_case_asm' (where
    88 t is the name of the datatype).
    89 
    90 * Classical reasoner / Simplifier combination: new force_tac (and
    91 derivatives Force_tac, force) combines rewriting and classical
    92 reasoning (and whatever other tools) similarly to auto_tac, but is
    93 aimed to solve the given subgoal completely.
    94 
    95 
    96 *** General ***
    97 
    98 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
    99 and `goalw': the theory is no longer needed as an explicit argument -
   100 the current theory context is used; assumptions are no longer returned
   101 at the ML-level unless one of them starts with ==> or !!; it is
   102 recommended to convert to these new commands using isatool fixgoal
   103 (backup your sources first!);
   104 
   105 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   106 the current theory context, and 'theory' to lookup stored theories;
   107 
   108 * new theory section 'locale' for declaring constants, assumptions and
   109 definitions that have local scope;
   110 
   111 * new theory section 'nonterminals' for purely syntactic types;
   112 
   113 * new theory section 'setup' for generic ML setup functions
   114 (e.g. package initialization);
   115 
   116 * the distribution now includes Isabelle icons: see
   117 lib/logo/isabelle-{small,tiny}.xpm;
   118 
   119 * isatool install - install binaries with absolute references to
   120 ISABELLE_HOME/bin;
   121 
   122 * isatool logo -- create instances of the Isabelle logo (as EPS);
   123 
   124 * print mode 'emacs' reserved for Isamode;
   125 
   126 * support multiple print (ast) translations per constant name;
   127 
   128 
   129 *** HOL ***
   130 
   131 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   132 
   133 * HOL/inductive package reorganized and improved: now supports mutual
   134 definitions such as
   135 
   136   inductive EVEN ODD
   137     intrs
   138       null "0 : EVEN"
   139       oddI "n : EVEN ==> Suc n : ODD"
   140       evenI "n : ODD ==> Suc n : EVEN"
   141 
   142 new theorem list "elims" contains an elimination rule for each of the
   143 recursive sets; inductive definitions now handle disjunctive premises
   144 correctly (also ZF);
   145 
   146 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   147 "mutual_induct" no longer exists - the induction rule is always
   148 contained in "induct";
   149 
   150 
   151 * HOL/datatype package re-implemented and greatly improved: now
   152 supports mutually recursive datatypes such as
   153 
   154   datatype
   155     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   156             | SUM ('a aexp) ('a aexp)
   157             | DIFF ('a aexp) ('a aexp)
   158             | NUM 'a
   159   and
   160     'a bexp = LESS ('a aexp) ('a aexp)
   161             | AND ('a bexp) ('a bexp)
   162             | OR ('a bexp) ('a bexp)
   163 
   164 as well as indirectly recursive datatypes such as
   165 
   166   datatype
   167     ('a, 'b) term = Var 'a
   168                   | App 'b ((('a, 'b) term) list)
   169 
   170 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   171 induction on mutually / indirectly recursive datatypes.
   172 
   173 Primrec equations are now stored in theory and can be accessed via
   174 <function_name>.simps.
   175 
   176 INCOMPATIBILITIES:
   177 
   178   - Theories using datatypes must now have theory Datatype as an
   179     ancestor.
   180   - The specific <typename>.induct_tac no longer exists - use the
   181     generic induct_tac instead.
   182   - natE has been renamed to nat.exhaust - use exhaust_tac
   183     instead of res_inst_tac ... natE. Note that the variable
   184     names in nat.exhaust differ from the names in natE, this
   185     may cause some "fragile" proofs to fail.
   186   - The theorems split_<typename>_case and split_<typename>_case_asm
   187     have been renamed to <typename>.split and <typename>.split_asm.
   188   - Since default sorts of type variables are now handled correctly,
   189     some datatype definitions may have to be annotated with explicit
   190     sort constraints.
   191   - Primrec definitions no longer require function name and type
   192     of recursive argument.
   193 
   194 Consider using isatool fixdatatype to adapt your theories and proof
   195 scripts to the new package (backup your sources first!).
   196 
   197 
   198 * HOL/record package: considerably improved implementation; now
   199 includes concrete syntax for record types, terms, updates; theorems
   200 for surjective pairing and splitting !!-bound record variables; proof
   201 support is as follows:
   202 
   203   1) standard conversions (selectors or updates applied to record
   204 constructor terms) are part of the standard simpset;
   205 
   206   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   207 made part of standard simpset and claset via addIffs;
   208 
   209   3) a tactic for record field splitting (record_split_tac) is part of
   210 the standard claset (addSWrapper);
   211 
   212 To get a better idea about these rules you may retrieve them via
   213 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   214 the name of your record type.
   215 
   216 The split tactic 3) conceptually simplifies by the following rule:
   217 
   218   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   219 
   220 Thus any record variable that is bound by meta-all will automatically
   221 blow up into some record constructor term, consequently the
   222 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   223 solve record problems automatically.
   224 
   225 
   226 * reorganized the main HOL image: HOL/Integ and String loaded by
   227 default; theory Main includes everything;
   228 
   229 * automatic simplification of integer sums and comparisons, using cancellation;
   230 
   231 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   232 
   233 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   234 
   235 * many new identities for unions, intersections, set difference, etc.;
   236 
   237 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   238 called split_if, split_split, split_sum_case and split_nat_case (to go
   239 with add/delsplits);
   240 
   241 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   242 (?x::unit) = (); this is made part of the default simpset, which COULD
   243 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   244 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   245 unit_abs_eta_conv is added in order to counter the effect of
   246 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   247 %u.f();
   248 
   249 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   250 makes more sense);
   251 
   252 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   253   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   254   disjointness reasoning but breaking a few old proofs.
   255 
   256 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   257 to 'converse' from 'inverse' (for compatibility with ZF and some
   258 literature);
   259 
   260 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   261 the well-founded relation;
   262 
   263 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   264     Compl A.  The "Compl" syntax remains available as input syntax for this
   265     release ONLY.
   266 
   267 * HOL/Update: new theory of function updates:
   268     f(a:=b) == %x. if x=a then b else f x
   269 may also be iterated as in f(a:=b,c:=d,...);
   270 
   271 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   272 
   273 * HOL/List:
   274   - new function list_update written xs[i:=v] that updates the i-th
   275     list position. May also be iterated as in xs[i:=a,j:=b,...].
   276   - new function `upt' written [i..j(] which generates the list
   277     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   278     bound write [i..j], which is a shorthand for [i..j+1(].
   279   - new lexicographic orderings and corresponding wellfoundedness theorems.
   280 
   281 * HOL/Arith:
   282   - removed 'pred' (predecessor) function;
   283   - generalized some theorems about n-1;
   284   - many new laws about "div" and "mod";
   285   - new laws about greatest common divisors (see theory ex/Primes);
   286 
   287 * HOL/Relation: renamed the relational operator r^-1 "converse"
   288 instead of "inverse";
   289 
   290 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   291   of the multiset ordering;
   292 
   293 * directory HOL/Real: a construction of the reals using Dedekind cuts
   294   (not included by default);
   295 
   296 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   297 
   298 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   299   programs, i.e. different program variables may have different types.
   300 
   301 * calling (stac rew i) now fails if "rew" has no effect on the goal
   302   [previously, this check worked only if the rewrite rule was unconditional]
   303   Now rew can involve either definitions or equalities (either == or =).
   304 
   305 
   306 *** ZF ***
   307 
   308 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   309   only the theorems proved on ZF.ML;
   310 
   311 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   312   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   313   disjointness reasoning but breaking a few old proofs.
   314 
   315 * ZF/Update: new theory of function updates
   316     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   317   may also be iterated as in f(a:=b,c:=d,...);
   318 
   319 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   320 
   321 * calling (stac rew i) now fails if "rew" has no effect on the goal
   322   [previously, this check worked only if the rewrite rule was unconditional]
   323   Now rew can involve either definitions or equalities (either == or =).
   324 
   325 * case_tac provided for compatibility with HOL
   326     (like the old excluded_middle_tac, but with subgoals swapped)
   327 
   328 
   329 *** Internal programming interfaces ***
   330 
   331 * Pure: several new basic modules made available for general use, see
   332 also src/Pure/README;
   333 
   334 * improved the theory data mechanism to support encapsulation (data
   335 kind name replaced by private Object.kind, acting as authorization
   336 key); new type-safe user interface via functor TheoryDataFun; generic
   337 print_data function becomes basically useless;
   338 
   339 * removed global_names compatibility flag -- all theory declarations
   340 are qualified by default;
   341 
   342 * module Pure/Syntax now offers quote / antiquote translation
   343 functions (useful for Hoare logic etc. with implicit dependencies);
   344 see HOL/ex/Antiquote for an example use;
   345 
   346 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   347 cterm -> thm;
   348 
   349 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   350 subgoal;
   351 
   352 * Display.print_goals function moved to Locale.print_goals;
   353 
   354 
   355 
   356 New in Isabelle98 (January 1998)
   357 --------------------------------
   358 
   359 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   360 
   361 * changed lexical syntax of terms / types: dots made part of long
   362 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   363 
   364 * simpset (and claset) reference variable replaced by functions
   365 simpset / simpset_ref;
   366 
   367 * no longer supports theory aliases (via merge) and non-trivial
   368 implicit merge of thms' signatures;
   369 
   370 * most internal names of constants changed due to qualified names;
   371 
   372 * changed Pure/Sequence interface (see Pure/seq.ML);
   373 
   374 
   375 *** General Changes ***
   376 
   377 * hierachically structured name spaces (for consts, types, axms, thms
   378 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   379 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   380 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   381 long_names for fully qualified output names; NOTE: ML programs
   382 (special tactics, packages etc.) referring to internal names may have
   383 to be adapted to cope with fully qualified names; in case of severe
   384 backward campatibility problems try setting 'global_names' at compile
   385 time to have enrything declared within a flat name space; one may also
   386 fine tune name declarations in theories via the 'global' and 'local'
   387 section;
   388 
   389 * reimplemented the implicit simpset and claset using the new anytype
   390 data filed in signatures; references simpset:simpset ref etc. are
   391 replaced by functions simpset:unit->simpset and
   392 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   393 to patch your ML files accordingly;
   394 
   395 * HTML output now includes theory graph data for display with Java
   396 applet or isatool browser; data generated automatically via isatool
   397 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   398 
   399 * defs may now be conditional; improved rewrite_goals_tac to handle
   400 conditional equations;
   401 
   402 * defs now admits additional type arguments, using TYPE('a) syntax;
   403 
   404 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   405 creates a new theory node; implicit merge of thms' signatures is
   406 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   407 transfer:theory->thm->thm in (rare) cases;
   408 
   409 * improved handling of draft signatures / theories; draft thms (and
   410 ctyps, cterms) are automatically promoted to real ones;
   411 
   412 * slightly changed interfaces for oracles: admit many per theory, named
   413 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   414 
   415 * print_goals: optional output of const types (set show_consts and
   416 show_types);
   417 
   418 * improved output of warnings (###) and errors (***);
   419 
   420 * subgoal_tac displays a warning if the new subgoal has type variables;
   421 
   422 * removed old README and Makefiles;
   423 
   424 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   425 
   426 * removed obsolete init_pps and init_database;
   427 
   428 * deleted the obsolete tactical STATE, which was declared by
   429     fun STATE tacfun st = tacfun st st;
   430 
   431 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   432 (which abbreviates $HOME);
   433 
   434 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   435 use isatool fixseq to adapt your ML programs (this works for fully
   436 qualified references to the Sequence structure only!);
   437 
   438 * use_thy no longer requires writable current directory; it always
   439 reloads .ML *and* .thy file, if either one is out of date;
   440 
   441 
   442 *** Classical Reasoner ***
   443 
   444 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   445 tactics that use classical reasoning to simplify a subgoal without
   446 splitting it into several subgoals;
   447 
   448 * Safe_tac: like safe_tac but uses the default claset;
   449 
   450 
   451 *** Simplifier ***
   452 
   453 * added simplification meta rules:
   454     (asm_)(full_)simplify: simpset -> thm -> thm;
   455 
   456 * simplifier.ML no longer part of Pure -- has to be loaded by object
   457 logics (again);
   458 
   459 * added prems argument to simplification procedures;
   460 
   461 * HOL, FOL, ZF: added infix function `addsplits':
   462   instead of `<simpset> setloop (split_tac <thms>)'
   463   you can simply write `<simpset> addsplits <thms>'
   464 
   465 
   466 *** Syntax ***
   467 
   468 * TYPE('a) syntax for type reflection terms;
   469 
   470 * no longer handles consts with name "" -- declare as 'syntax' instead;
   471 
   472 * pretty printer: changed order of mixfix annotation preference (again!);
   473 
   474 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   475 
   476 
   477 *** HOL ***
   478 
   479 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   480   with `addloop' of the simplifier to faciliate case splitting in premises.
   481 
   482 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   483 
   484 * HOL/Auth: new protocol proofs including some for the Internet
   485   protocol TLS;
   486 
   487 * HOL/Map: new theory of `maps' a la VDM;
   488 
   489 * HOL/simplifier: simplification procedures nat_cancel_sums for
   490 cancelling out common nat summands from =, <, <= (in)equalities, or
   491 differences; simplification procedures nat_cancel_factor for
   492 cancelling common factor from =, <, <= (in)equalities over natural
   493 sums; nat_cancel contains both kinds of procedures, it is installed by
   494 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   495 
   496 * HOL/simplifier: terms of the form
   497   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   498   are rewritten to
   499   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   500   and those of the form
   501   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   502   are rewritten to
   503   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   504 
   505 * HOL/datatype
   506   Each datatype `t' now comes with a theorem `split_t_case' of the form
   507 
   508   P(t_case f1 ... fn x) =
   509      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   510         ...
   511        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   512      )
   513 
   514   and a theorem `split_t_case_asm' of the form
   515 
   516   P(t_case f1 ... fn x) =
   517     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   518         ...
   519        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   520      )
   521   which can be added to a simpset via `addsplits'. The existing theorems
   522   expand_list_case and expand_option_case have been renamed to
   523   split_list_case and split_option_case.
   524 
   525 * HOL/Arithmetic:
   526   - `pred n' is automatically converted to `n-1'.
   527     Users are strongly encouraged not to use `pred' any longer,
   528     because it will disappear altogether at some point.
   529   - Users are strongly encouraged to write "0 < n" rather than
   530     "n ~= 0". Theorems and proof tools have been modified towards this
   531     `standard'.
   532 
   533 * HOL/Lists:
   534   the function "set_of_list" has been renamed "set" (and its theorems too);
   535   the function "nth" now takes its arguments in the reverse order and
   536   has acquired the infix notation "!" as in "xs!n".
   537 
   538 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   539 
   540 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   541   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   542 
   543 * HOL/record: extensible records with schematic structural subtyping
   544 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   545 still lacks various theorems and concrete record syntax;
   546 
   547 
   548 *** HOLCF ***
   549 
   550 * removed "axioms" and "generated by" sections;
   551 
   552 * replaced "ops" section by extended "consts" section, which is capable of
   553   handling the continuous function space "->" directly;
   554 
   555 * domain package:
   556   . proves theorems immediately and stores them in the theory,
   557   . creates hierachical name space,
   558   . now uses normal mixfix annotations (instead of cinfix...),
   559   . minor changes to some names and values (for consistency),
   560   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   561   . separator between mutual domain defs: changed "," to "and",
   562   . improved handling of sort constraints;  now they have to
   563     appear on the left-hand side of the equations only;
   564 
   565 * fixed LAM <x,y,zs>.b syntax;
   566 
   567 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   568 adm (%x. P (t x)), where P is chainfinite and t continuous;
   569 
   570 
   571 *** FOL and ZF ***
   572 
   573 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   574   with `addloop' of the simplifier to faciliate case splitting in premises.
   575 
   576 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   577 in HOL, they strip ALL and --> from proved theorems;
   578 
   579 
   580 
   581 New in Isabelle94-8 (May 1997)
   582 ------------------------------
   583 
   584 *** General Changes ***
   585 
   586 * new utilities to build / run / maintain Isabelle etc. (in parts
   587 still somewhat experimental); old Makefiles etc. still functional;
   588 
   589 * new 'Isabelle System Manual';
   590 
   591 * INSTALL text, together with ./configure and ./build scripts;
   592 
   593 * reimplemented type inference for greater efficiency, better error
   594 messages and clean internal interface;
   595 
   596 * prlim command for dealing with lots of subgoals (an easier way of
   597 setting goals_limit);
   598 
   599 
   600 *** Syntax ***
   601 
   602 * supports alternative (named) syntax tables (parser and pretty
   603 printer); internal interface is provided by add_modesyntax(_i);
   604 
   605 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   606 be used in conjunction with the Isabelle symbol font; uses the
   607 "symbols" syntax table;
   608 
   609 * added token_translation interface (may translate name tokens in
   610 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   611 the current print_mode); IMPORTANT: user print translation functions
   612 are responsible for marking newly introduced bounds
   613 (Syntax.mark_boundT);
   614 
   615 * token translations for modes "xterm" and "xterm_color" that display
   616 names in bold, underline etc. or colors (which requires a color
   617 version of xterm);
   618 
   619 * infixes may now be declared with names independent of their syntax;
   620 
   621 * added typed_print_translation (like print_translation, but may
   622 access type of constant);
   623 
   624 
   625 *** Classical Reasoner ***
   626 
   627 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   628 some limitations.  Blast_tac...
   629   + ignores addss, addbefore, addafter; this restriction is intrinsic
   630   + ignores elimination rules that don't have the correct format
   631         (the conclusion MUST be a formula variable)
   632   + ignores types, which can make HOL proofs fail
   633   + rules must not require higher-order unification, e.g. apply_type in ZF
   634     [message "Function Var's argument not a bound variable" relates to this]
   635   + its proof strategy is more general but can actually be slower
   636 
   637 * substitution with equality assumptions no longer permutes other
   638 assumptions;
   639 
   640 * minor changes in semantics of addafter (now called addaltern); renamed
   641 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   642 (and access functions for it);
   643 
   644 * improved combination of classical reasoner and simplifier:
   645   + functions for handling clasimpsets
   646   + improvement of addss: now the simplifier is called _after_ the
   647     safe steps.
   648   + safe variant of addss called addSss: uses safe simplifications
   649     _during_ the safe steps. It is more complete as it allows multiple
   650     instantiations of unknowns (e.g. with slow_tac).
   651 
   652 *** Simplifier ***
   653 
   654 * added interface for simplification procedures (functions that
   655 produce *proven* rewrite rules on the fly, depending on current
   656 redex);
   657 
   658 * ordering on terms as parameter (used for ordered rewriting);
   659 
   660 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   661 
   662 * the solver is now split into a safe and an unsafe part.
   663 This should be invisible for the normal user, except that the
   664 functions setsolver and addsolver have been renamed to setSolver and
   665 addSolver; added safe_asm_full_simp_tac;
   666 
   667 
   668 *** HOL ***
   669 
   670 * a generic induction tactic `induct_tac' which works for all datatypes and
   671 also for type `nat';
   672 
   673 * a generic case distinction tactic `exhaust_tac' which works for all
   674 datatypes and also for type `nat';
   675 
   676 * each datatype comes with a function `size';
   677 
   678 * patterns in case expressions allow tuple patterns as arguments to
   679 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   680 
   681 * primrec now also works with type nat;
   682 
   683 * recdef: a new declaration form, allows general recursive functions to be
   684 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   685 
   686 * the constant for negation has been renamed from "not" to "Not" to
   687 harmonize with FOL, ZF, LK, etc.;
   688 
   689 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   690 infinite lists;
   691 
   692 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   693 
   694 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   695 problems in commutative rings, using axiomatic type classes for + and *;
   696 
   697 * more examples in HOL/MiniML and HOL/Auth;
   698 
   699 * more default rewrite rules for quantifiers, union/intersection;
   700 
   701 * a new constant `arbitrary == @x.False';
   702 
   703 * HOLCF/IOA replaces old HOL/IOA;
   704 
   705 * HOLCF changes: derived all rules and arities
   706   + axiomatic type classes instead of classes
   707   + typedef instead of faking type definitions
   708   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   709   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   710   + eliminated the types void, one, tr
   711   + use unit lift and bool lift (with translations) instead of one and tr
   712   + eliminated blift from Lift3.thy (use Def instead of blift)
   713   all eliminated rules are derived as theorems --> no visible changes ;
   714 
   715 
   716 *** ZF ***
   717 
   718 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   719 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   720 as ZF_cs addSIs [equalityI];
   721 
   722 
   723 
   724 New in Isabelle94-7 (November 96)
   725 ---------------------------------
   726 
   727 * allowing negative levels (as offsets) in prlev and choplev;
   728 
   729 * super-linear speedup for large simplifications;
   730 
   731 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   732 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   733 FAIL); can suppress it using the command Delsimps (ex_simps @
   734 all_simps); De Morgan laws are also now included, by default;
   735 
   736 * improved printing of ==>  :  ~:
   737 
   738 * new object-logic "Sequents" adds linear logic, while replacing LK
   739 and Modal (thanks to Sara Kalvala);
   740 
   741 * HOL/Auth: correctness proofs for authentication protocols;
   742 
   743 * HOL: new auto_tac combines rewriting and classical reasoning (many
   744 examples on HOL/Auth);
   745 
   746 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   747 the rewriter and classical reasoner simultaneously;
   748 
   749 * function uresult no longer returns theorems in "standard" format;
   750 regain previous version by: val uresult = standard o uresult;
   751 
   752 
   753 
   754 New in Isabelle94-6
   755 -------------------
   756 
   757 * oracles -- these establish an interface between Isabelle and trusted
   758 external reasoners, which may deliver results as theorems;
   759 
   760 * proof objects (in particular record all uses of oracles);
   761 
   762 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   763 
   764 * "constdefs" section in theory files;
   765 
   766 * "primrec" section (HOL) no longer requires names;
   767 
   768 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   769 
   770 
   771 
   772 New in Isabelle94-5
   773 -------------------
   774 
   775 * reduced space requirements;
   776 
   777 * automatic HTML generation from theories;
   778 
   779 * theory files no longer require "..." (quotes) around most types;
   780 
   781 * new examples, including two proofs of the Church-Rosser theorem;
   782 
   783 * non-curried (1994) version of HOL is no longer distributed;
   784 
   785 
   786 
   787 New in Isabelle94-4
   788 -------------------
   789 
   790 * greatly reduced space requirements;
   791 
   792 * theory files (.thy) no longer require \...\ escapes at line breaks;
   793 
   794 * searchable theorem database (see the section "Retrieving theorems" on
   795 page 8 of the Reference Manual);
   796 
   797 * new examples, including Grabczewski's monumental case study of the
   798 Axiom of Choice;
   799 
   800 * The previous version of HOL renamed to Old_HOL;
   801 
   802 * The new version of HOL (previously called CHOL) uses a curried syntax
   803 for functions.  Application looks like f a b instead of f(a,b);
   804 
   805 * Mutually recursive inductive definitions finally work in HOL;
   806 
   807 * In ZF, pattern-matching on tuples is now available in all abstractions and
   808 translates to the operator "split";
   809 
   810 
   811 
   812 New in Isabelle94-3
   813 -------------------
   814 
   815 * new infix operator, addss, allowing the classical reasoner to
   816 perform simplification at each step of its search.  Example:
   817         fast_tac (cs addss ss)
   818 
   819 * a new logic, CHOL, the same as HOL, but with a curried syntax
   820 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
   821 look like (a,b) instead of <a,b>;
   822 
   823 * PLEASE NOTE: CHOL will eventually replace HOL!
   824 
   825 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   826 It translates to the operator "split".  A new theory of integers is available;
   827 
   828 * In ZF, integer numerals now denote two's-complement binary integers.
   829 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   830 
   831 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
   832 of the Axiom of Choice;
   833 
   834 
   835 
   836 New in Isabelle94-2
   837 -------------------
   838 
   839 * Significantly faster resolution;
   840 
   841 * the different sections in a .thy file can now be mixed and repeated
   842 freely;
   843 
   844 * Database of theorems for FOL, HOL and ZF.  New
   845 commands including qed, qed_goal and bind_thm store theorems in the database.
   846 
   847 * Simple database queries: return a named theorem (get_thm) or all theorems of
   848 a given theory (thms_of), or find out what theory a theorem was proved in
   849 (theory_of_thm);
   850 
   851 * Bugs fixed in the inductive definition and datatype packages;
   852 
   853 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   854 and HOL_dup_cs obsolete;
   855 
   856 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   857 have been removed;
   858 
   859 * Simpler definition of function space in ZF;
   860 
   861 * new results about cardinal and ordinal arithmetic in ZF;
   862 
   863 * 'subtype' facility in HOL for introducing new types as subsets of existing
   864 types;
   865 
   866 
   867 $Id$