NEWS
author paulson
Thu Oct 22 10:57:18 1998 +0200 (1998-10-22)
changeset 5722 c669e2161b08
parent 5710 30f4d3713cbe
child 5726 5de7e399ec88
permissions -rw-r--r--
locales
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     8 
     9 * several changes of proof tools;
    10 
    11 * HOL: new version of inductive and datatype;
    12 
    13 * HOL: major changes to the inductive and datatype packages;
    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 - is now overloaded (new type constraints may be required);
    23 
    24 * HOL and ZF: unary minus for integers is now #- instead of #~.  In ZF, 
    25   expressions such as n#-1 must be changed to n#- 1, since #-1 is now taken
    26   as an integer constant.
    27 
    28 * Pure: ML function 'theory_of' replaced by 'theory';
    29 
    30 
    31 *** Proof tools ***
    32 
    33 * Simplifier:
    34   1. 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   2. The simplifier now knows a little bit about nat-arithmetic.
    42 
    43 * Classical reasoner: wrapper mechanism for the classical reasoner now
    44 allows for selected deletion of wrappers, by introduction of names for
    45 wrapper functionals.  This implies that addbefore, addSbefore,
    46 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    47 and that adding two tactics with the same name overwrites the first
    48 one (emitting a warning).
    49   type wrapper = (int -> tactic) -> (int -> tactic)
    50   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    51   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    52   delWrapper, delSWrapper: claset *  string            -> claset
    53   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    54 
    55 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
    56   semantics; addbefore now affects only the unsafe part of step_tac
    57   etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
    58   FAIL, but proofs should be fixable easily, e.g. by replacing
    59   Auto_tac by Force_tac;
    60 
    61 * Classical reasoner: setwrapper to setWrapper and compwrapper to compWrapper; 
    62   added safe wrapper (and access functions for it);
    63 
    64 * HOL/split_all_tac is now much faster and fails if there is nothing
    65 to split.  Existing (fragile) proofs may require adaption because the
    66 order and the names of the automatically generated variables have
    67 changed.  split_all_tac has moved within claset() from unsafe wrappers
    68 to safe wrappers, which means that !!-bound variables are split much
    69 more aggressively, and safe_tac and clarify_tac now split such
    70 variables.  If this splitting is not appropriate, use delSWrapper
    71 "split_all_tac".
    72 
    73 * HOL/Simplifier:
    74 
    75  - Rewrite rules for case distinctions can now be added permanently to
    76    the default simpset using Addsplits just like Addsimps. They can be
    77    removed via Delsplits just like Delsimps. Lower-case versions are
    78    also available.
    79 
    80  - The rule split_if is now part of the default simpset. This means
    81    that the simplifier will eliminate all occurrences of if-then-else
    82    in the conclusion of a goal. To prevent this, you can either remove
    83    split_if completely from the default simpset by `Delsplits
    84    [split_if]' or remove it in a specific call of the simplifier using
    85    `... delsplits [split_if]'.  You can also add/delete other case
    86    splitting rules to/from the default simpset: every datatype
    87    generates suitable rules `split_t_case' and `split_t_case_asm'
    88    (where 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 
   127 *** HOL ***
   128 
   129 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   130 
   131 * HOL/inductive package reorganized and improved: now supports mutual
   132 definitions such as
   133 
   134   inductive EVEN ODD
   135     intrs
   136       null "0 : EVEN"
   137       oddI "n : EVEN ==> Suc n : ODD"
   138       evenI "n : ODD ==> Suc n : EVEN"
   139 
   140 new theorem list "elims" contains an elimination rule for each of the
   141 recursive sets; inductive definitions now handle disjunctive premises
   142 correctly (also ZF);
   143 
   144 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   145 "mutual_induct" no longer exists - the induction rule is always
   146 contained in "induct";
   147 
   148 
   149 * HOL/datatype package re-implemented and greatly improved: now
   150 supports mutually recursive datatypes such as
   151 
   152   datatype
   153     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   154             | SUM ('a aexp) ('a aexp)
   155             | DIFF ('a aexp) ('a aexp)
   156             | NUM 'a
   157   and
   158     'a bexp = LESS ('a aexp) ('a aexp)
   159             | AND ('a bexp) ('a bexp)
   160             | OR ('a bexp) ('a bexp)
   161 
   162 as well as indirectly recursive datatypes such as
   163 
   164   datatype
   165     ('a, 'b) term = Var 'a
   166                   | App 'b ((('a, 'b) term) list)
   167 
   168 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   169 induction on mutually / indirectly recursive datatypes.
   170 
   171 Primrec equations are now stored in theory and can be accessed via
   172 <function_name>.simps.
   173 
   174 INCOMPATIBILITIES:
   175 
   176   - Theories using datatypes must now have theory Datatype as an
   177     ancestor.
   178   - The specific <typename>.induct_tac no longer exists - use the
   179     generic induct_tac instead.
   180   - natE has been renamed to nat.exhaust - use exhaust_tac
   181     instead of res_inst_tac ... natE. Note that the variable
   182     names in nat.exhaust differ from the names in natE, this
   183     may cause some "fragile" proofs to fail.
   184   - The theorems split_<typename>_case and split_<typename>_case_asm
   185     have been renamed to <typename>.split and <typename>.split_asm.
   186   - Since default sorts of type variables are now handled correctly,
   187     some datatype definitions may have to be annotated with explicit
   188     sort constraints.
   189   - Primrec definitions no longer require function name and type
   190     of recursive argument.
   191 
   192 Consider using isatool fixdatatype to adapt your theories and proof
   193 scripts to the new package (backup your sources first!).
   194 
   195 
   196 * HOL/record package: now includes concrete syntax for record types,
   197 terms, updates; still lacks important theorems, like surjective
   198 pairing and split;
   199 
   200 * reorganized the main HOL image: HOL/Integ and String loaded by
   201 default; theory Main includes everything;
   202 
   203 * automatic simplification of integer sums and comparisons, using cancellation;
   204 
   205 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   206 
   207 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   208 
   209 * many new identities for unions, intersections, set difference, etc.;
   210 
   211 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   212 called split_if, split_split, split_sum_case and split_nat_case (to go
   213 with add/delsplits);
   214 
   215 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   216 (?x::unit) = (); this is made part of the default simpset, which COULD
   217 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   218 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   219 unit_abs_eta_conv is added in order to counter the effect of
   220 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   221 %u.f();
   222 
   223 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   224 makes more sense);
   225 
   226 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   227   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   228   disjointness reasoning but breaking a few old proofs.
   229 
   230 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   231 to 'converse' from 'inverse' (for compatibility with ZF and some
   232 literature);
   233 
   234 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   235 the well-founded relation;
   236 
   237 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   238     Compl A.  The "Compl" syntax remains available as input syntax for this
   239     release ONLY.
   240 
   241 * HOL/Update: new theory of function updates:
   242     f(a:=b) == %x. if x=a then b else f x
   243 may also be iterated as in f(a:=b,c:=d,...);
   244 
   245 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   246 
   247 * HOL/List:
   248   - new function list_update written xs[i:=v] that updates the i-th
   249     list position. May also be iterated as in xs[i:=a,j:=b,...].
   250   - new function `upt' written [i..j(] which generates the list
   251     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   252     bound write [i..j], which is a shorthand for [i..j+1(].
   253   - new lexicographic orderings and corresponding wellfoundedness theorems.
   254 
   255 * HOL/Arith:
   256   - removed 'pred' (predecessor) function;
   257   - generalized some theorems about n-1;
   258   - many new laws about "div" and "mod";
   259   - new laws about greatest common divisors (see theory ex/Primes);
   260 
   261 * HOL/Relation: renamed the relational operator r^-1 "converse"
   262 instead of "inverse";
   263 
   264 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   265   of the multiset ordering;
   266 
   267 * directory HOL/Real: a construction of the reals using Dedekind cuts
   268   (not included by default);
   269 
   270 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   271 
   272 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   273   programs, i.e. different program variables may have different types.
   274 
   275 * calling (stac rew i) now fails if "rew" has no effect on the goal
   276   [previously, this check worked only if the rewrite rule was unconditional]
   277   Now rew can involve either definitions or equalities (either == or =).
   278 
   279 
   280 *** ZF ***
   281 
   282 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   283   only the theorems proved on ZF.ML;
   284 
   285 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   286   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   287   disjointness reasoning but breaking a few old proofs.
   288 
   289 * ZF/Update: new theory of function updates
   290     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   291   may also be iterated as in f(a:=b,c:=d,...);
   292 
   293 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   294 
   295 * calling (stac rew i) now fails if "rew" has no effect on the goal
   296   [previously, this check worked only if the rewrite rule was unconditional]
   297   Now rew can involve either definitions or equalities (either == or =).
   298 
   299 * case_tac provided for compatibility with HOL
   300     (like the old excluded_middle_tac, but with subgoals swapped)
   301 
   302 
   303 *** Internal programming interfaces ***
   304 
   305 * Pure: several new basic modules made available for general use, see
   306 also src/Pure/README;
   307 
   308 * improved the theory data mechanism to support encapsulation (data
   309 kind name replaced by private Object.kind, acting as authorization
   310 key); new type-safe user interface via functor TheoryDataFun; generic
   311 print_data function becomes basically useless;
   312 
   313 * removed global_names compatibility flag -- all theory declarations
   314 are qualified by default;
   315 
   316 * module Pure/Syntax now offers quote / antiquote translation
   317 functions (useful for Hoare logic etc. with implicit dependencies);
   318 see HOL/ex/Antiquote for an example use;
   319 
   320 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   321 cterm -> thm;
   322 
   323 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   324 subgoal;
   325 
   326 * Display.print_goals function moved to Locale.print_goals;
   327 
   328 
   329 
   330 New in Isabelle98 (January 1998)
   331 --------------------------------
   332 
   333 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   334 
   335 * changed lexical syntax of terms / types: dots made part of long
   336 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   337 
   338 * simpset (and claset) reference variable replaced by functions
   339 simpset / simpset_ref;
   340 
   341 * no longer supports theory aliases (via merge) and non-trivial
   342 implicit merge of thms' signatures;
   343 
   344 * most internal names of constants changed due to qualified names;
   345 
   346 * changed Pure/Sequence interface (see Pure/seq.ML);
   347 
   348 
   349 *** General Changes ***
   350 
   351 * hierachically structured name spaces (for consts, types, axms, thms
   352 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   353 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   354 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   355 long_names for fully qualified output names; NOTE: ML programs
   356 (special tactics, packages etc.) referring to internal names may have
   357 to be adapted to cope with fully qualified names; in case of severe
   358 backward campatibility problems try setting 'global_names' at compile
   359 time to have enrything declared within a flat name space; one may also
   360 fine tune name declarations in theories via the 'global' and 'local'
   361 section;
   362 
   363 * reimplemented the implicit simpset and claset using the new anytype
   364 data filed in signatures; references simpset:simpset ref etc. are
   365 replaced by functions simpset:unit->simpset and
   366 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   367 to patch your ML files accordingly;
   368 
   369 * HTML output now includes theory graph data for display with Java
   370 applet or isatool browser; data generated automatically via isatool
   371 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   372 
   373 * defs may now be conditional; improved rewrite_goals_tac to handle
   374 conditional equations;
   375 
   376 * defs now admits additional type arguments, using TYPE('a) syntax;
   377 
   378 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   379 creates a new theory node; implicit merge of thms' signatures is
   380 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   381 transfer:theory->thm->thm in (rare) cases;
   382 
   383 * improved handling of draft signatures / theories; draft thms (and
   384 ctyps, cterms) are automatically promoted to real ones;
   385 
   386 * slightly changed interfaces for oracles: admit many per theory, named
   387 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   388 
   389 * print_goals: optional output of const types (set show_consts and
   390 show_types);
   391 
   392 * improved output of warnings (###) and errors (***);
   393 
   394 * subgoal_tac displays a warning if the new subgoal has type variables;
   395 
   396 * removed old README and Makefiles;
   397 
   398 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   399 
   400 * removed obsolete init_pps and init_database;
   401 
   402 * deleted the obsolete tactical STATE, which was declared by
   403     fun STATE tacfun st = tacfun st st;
   404 
   405 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   406 (which abbreviates $HOME);
   407 
   408 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   409 use isatool fixseq to adapt your ML programs (this works for fully
   410 qualified references to the Sequence structure only!);
   411 
   412 * use_thy no longer requires writable current directory; it always
   413 reloads .ML *and* .thy file, if either one is out of date;
   414 
   415 
   416 *** Classical Reasoner ***
   417 
   418 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   419 tactics that use classical reasoning to simplify a subgoal without
   420 splitting it into several subgoals;
   421 
   422 * Safe_tac: like safe_tac but uses the default claset;
   423 
   424 
   425 *** Simplifier ***
   426 
   427 * added simplification meta rules:
   428     (asm_)(full_)simplify: simpset -> thm -> thm;
   429 
   430 * simplifier.ML no longer part of Pure -- has to be loaded by object
   431 logics (again);
   432 
   433 * added prems argument to simplification procedures;
   434 
   435 * HOL, FOL, ZF: added infix function `addsplits':
   436   instead of `<simpset> setloop (split_tac <thms>)'
   437   you can simply write `<simpset> addsplits <thms>'
   438 
   439 
   440 *** Syntax ***
   441 
   442 * TYPE('a) syntax for type reflection terms;
   443 
   444 * no longer handles consts with name "" -- declare as 'syntax' instead;
   445 
   446 * pretty printer: changed order of mixfix annotation preference (again!);
   447 
   448 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   449 
   450 
   451 *** HOL ***
   452 
   453 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   454   with `addloop' of the simplifier to faciliate case splitting in premises.
   455 
   456 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   457 
   458 * HOL/Auth: new protocol proofs including some for the Internet
   459   protocol TLS;
   460 
   461 * HOL/Map: new theory of `maps' a la VDM;
   462 
   463 * HOL/simplifier: simplification procedures nat_cancel_sums for
   464 cancelling out common nat summands from =, <, <= (in)equalities, or
   465 differences; simplification procedures nat_cancel_factor for
   466 cancelling common factor from =, <, <= (in)equalities over natural
   467 sums; nat_cancel contains both kinds of procedures, it is installed by
   468 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   469 
   470 * HOL/simplifier: terms of the form
   471   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   472   are rewritten to
   473   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   474   and those of the form
   475   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   476   are rewritten to
   477   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   478 
   479 * HOL/datatype
   480   Each datatype `t' now comes with a theorem `split_t_case' of the form
   481 
   482   P(t_case f1 ... fn x) =
   483      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   484         ...
   485        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   486      )
   487 
   488   and a theorem `split_t_case_asm' of the form
   489 
   490   P(t_case f1 ... fn x) =
   491     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   492         ...
   493        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   494      )
   495   which can be added to a simpset via `addsplits'. The existing theorems
   496   expand_list_case and expand_option_case have been renamed to
   497   split_list_case and split_option_case.
   498 
   499 * HOL/Arithmetic:
   500   - `pred n' is automatically converted to `n-1'.
   501     Users are strongly encouraged not to use `pred' any longer,
   502     because it will disappear altogether at some point.
   503   - Users are strongly encouraged to write "0 < n" rather than
   504     "n ~= 0". Theorems and proof tools have been modified towards this
   505     `standard'.
   506 
   507 * HOL/Lists:
   508   the function "set_of_list" has been renamed "set" (and its theorems too);
   509   the function "nth" now takes its arguments in the reverse order and
   510   has acquired the infix notation "!" as in "xs!n".
   511 
   512 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   513 
   514 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   515   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   516 
   517 * HOL/record: extensible records with schematic structural subtyping
   518 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   519 still lacks various theorems and concrete record syntax;
   520 
   521 
   522 *** HOLCF ***
   523 
   524 * removed "axioms" and "generated by" sections;
   525 
   526 * replaced "ops" section by extended "consts" section, which is capable of
   527   handling the continuous function space "->" directly;
   528 
   529 * domain package:
   530   . proves theorems immediately and stores them in the theory,
   531   . creates hierachical name space,
   532   . now uses normal mixfix annotations (instead of cinfix...),
   533   . minor changes to some names and values (for consistency),
   534   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   535   . separator between mutual domain defs: changed "," to "and",
   536   . improved handling of sort constraints;  now they have to
   537     appear on the left-hand side of the equations only;
   538 
   539 * fixed LAM <x,y,zs>.b syntax;
   540 
   541 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   542 adm (%x. P (t x)), where P is chainfinite and t continuous;
   543 
   544 
   545 *** FOL and ZF ***
   546 
   547 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   548   with `addloop' of the simplifier to faciliate case splitting in premises.
   549 
   550 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   551 in HOL, they strip ALL and --> from proved theorems;
   552 
   553 
   554 
   555 New in Isabelle94-8 (May 1997)
   556 ------------------------------
   557 
   558 *** General Changes ***
   559 
   560 * new utilities to build / run / maintain Isabelle etc. (in parts
   561 still somewhat experimental); old Makefiles etc. still functional;
   562 
   563 * new 'Isabelle System Manual';
   564 
   565 * INSTALL text, together with ./configure and ./build scripts;
   566 
   567 * reimplemented type inference for greater efficiency, better error
   568 messages and clean internal interface;
   569 
   570 * prlim command for dealing with lots of subgoals (an easier way of
   571 setting goals_limit);
   572 
   573 
   574 *** Syntax ***
   575 
   576 * supports alternative (named) syntax tables (parser and pretty
   577 printer); internal interface is provided by add_modesyntax(_i);
   578 
   579 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   580 be used in conjunction with the Isabelle symbol font; uses the
   581 "symbols" syntax table;
   582 
   583 * added token_translation interface (may translate name tokens in
   584 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   585 the current print_mode); IMPORTANT: user print translation functions
   586 are responsible for marking newly introduced bounds
   587 (Syntax.mark_boundT);
   588 
   589 * token translations for modes "xterm" and "xterm_color" that display
   590 names in bold, underline etc. or colors (which requires a color
   591 version of xterm);
   592 
   593 * infixes may now be declared with names independent of their syntax;
   594 
   595 * added typed_print_translation (like print_translation, but may
   596 access type of constant);
   597 
   598 
   599 *** Classical Reasoner ***
   600 
   601 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   602 some limitations.  Blast_tac...
   603   + ignores addss, addbefore, addafter; this restriction is intrinsic
   604   + ignores elimination rules that don't have the correct format
   605 	(the conclusion MUST be a formula variable)
   606   + ignores types, which can make HOL proofs fail
   607   + rules must not require higher-order unification, e.g. apply_type in ZF
   608     [message "Function Var's argument not a bound variable" relates to this]
   609   + its proof strategy is more general but can actually be slower
   610 
   611 * substitution with equality assumptions no longer permutes other
   612 assumptions;
   613 
   614 * minor changes in semantics of addafter (now called addaltern); renamed
   615 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   616 (and access functions for it);
   617 
   618 * improved combination of classical reasoner and simplifier: 
   619   + functions for handling clasimpsets
   620   + improvement of addss: now the simplifier is called _after_ the
   621     safe steps.
   622   + safe variant of addss called addSss: uses safe simplifications
   623     _during_ the safe steps. It is more complete as it allows multiple 
   624     instantiations of unknowns (e.g. with slow_tac).
   625 
   626 *** Simplifier ***
   627 
   628 * added interface for simplification procedures (functions that
   629 produce *proven* rewrite rules on the fly, depending on current
   630 redex);
   631 
   632 * ordering on terms as parameter (used for ordered rewriting);
   633 
   634 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   635 
   636 * the solver is now split into a safe and an unsafe part.
   637 This should be invisible for the normal user, except that the
   638 functions setsolver and addsolver have been renamed to setSolver and
   639 addSolver; added safe_asm_full_simp_tac;
   640 
   641 
   642 *** HOL ***
   643 
   644 * a generic induction tactic `induct_tac' which works for all datatypes and
   645 also for type `nat';
   646 
   647 * a generic case distinction tactic `exhaust_tac' which works for all
   648 datatypes and also for type `nat';
   649 
   650 * each datatype comes with a function `size';
   651 
   652 * patterns in case expressions allow tuple patterns as arguments to
   653 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   654 
   655 * primrec now also works with type nat;
   656 
   657 * recdef: a new declaration form, allows general recursive functions to be
   658 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   659 
   660 * the constant for negation has been renamed from "not" to "Not" to
   661 harmonize with FOL, ZF, LK, etc.;
   662 
   663 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   664 infinite lists;
   665 
   666 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   667 
   668 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   669 problems in commutative rings, using axiomatic type classes for + and *;
   670 
   671 * more examples in HOL/MiniML and HOL/Auth;
   672 
   673 * more default rewrite rules for quantifiers, union/intersection;
   674 
   675 * a new constant `arbitrary == @x.False';
   676 
   677 * HOLCF/IOA replaces old HOL/IOA;
   678 
   679 * HOLCF changes: derived all rules and arities 
   680   + axiomatic type classes instead of classes 
   681   + typedef instead of faking type definitions
   682   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   683   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   684   + eliminated the types void, one, tr
   685   + use unit lift and bool lift (with translations) instead of one and tr
   686   + eliminated blift from Lift3.thy (use Def instead of blift)
   687   all eliminated rules are derived as theorems --> no visible changes ;
   688 
   689 
   690 *** ZF ***
   691 
   692 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   693 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   694 as ZF_cs addSIs [equalityI];
   695 
   696 
   697 
   698 New in Isabelle94-7 (November 96)
   699 ---------------------------------
   700 
   701 * allowing negative levels (as offsets) in prlev and choplev;
   702 
   703 * super-linear speedup for large simplifications;
   704 
   705 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   706 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   707 FAIL); can suppress it using the command Delsimps (ex_simps @
   708 all_simps); De Morgan laws are also now included, by default;
   709 
   710 * improved printing of ==>  :  ~:
   711 
   712 * new object-logic "Sequents" adds linear logic, while replacing LK
   713 and Modal (thanks to Sara Kalvala);
   714 
   715 * HOL/Auth: correctness proofs for authentication protocols;
   716 
   717 * HOL: new auto_tac combines rewriting and classical reasoning (many
   718 examples on HOL/Auth);
   719 
   720 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   721 the rewriter and classical reasoner simultaneously;
   722 
   723 * function uresult no longer returns theorems in "standard" format;
   724 regain previous version by: val uresult = standard o uresult;
   725 
   726 
   727 
   728 New in Isabelle94-6
   729 -------------------
   730 
   731 * oracles -- these establish an interface between Isabelle and trusted
   732 external reasoners, which may deliver results as theorems;
   733 
   734 * proof objects (in particular record all uses of oracles);
   735 
   736 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   737 
   738 * "constdefs" section in theory files;
   739 
   740 * "primrec" section (HOL) no longer requires names;
   741 
   742 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   743 
   744 
   745 
   746 New in Isabelle94-5
   747 -------------------
   748 
   749 * reduced space requirements;
   750 
   751 * automatic HTML generation from theories;
   752 
   753 * theory files no longer require "..." (quotes) around most types;
   754 
   755 * new examples, including two proofs of the Church-Rosser theorem;
   756 
   757 * non-curried (1994) version of HOL is no longer distributed;
   758 
   759 
   760 
   761 New in Isabelle94-4
   762 -------------------
   763 
   764 * greatly reduced space requirements;
   765 
   766 * theory files (.thy) no longer require \...\ escapes at line breaks;
   767 
   768 * searchable theorem database (see the section "Retrieving theorems" on 
   769 page 8 of the Reference Manual);
   770 
   771 * new examples, including Grabczewski's monumental case study of the
   772 Axiom of Choice;
   773 
   774 * The previous version of HOL renamed to Old_HOL;
   775 
   776 * The new version of HOL (previously called CHOL) uses a curried syntax 
   777 for functions.  Application looks like f a b instead of f(a,b);
   778 
   779 * Mutually recursive inductive definitions finally work in HOL;
   780 
   781 * In ZF, pattern-matching on tuples is now available in all abstractions and
   782 translates to the operator "split";
   783 
   784 
   785 
   786 New in Isabelle94-3
   787 -------------------
   788 
   789 * new infix operator, addss, allowing the classical reasoner to 
   790 perform simplification at each step of its search.  Example:
   791 	fast_tac (cs addss ss)
   792 
   793 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   794 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   795 look like (a,b) instead of <a,b>;
   796 
   797 * PLEASE NOTE: CHOL will eventually replace HOL!
   798 
   799 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   800 It translates to the operator "split".  A new theory of integers is available;
   801 
   802 * In ZF, integer numerals now denote two's-complement binary integers.
   803 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   804 
   805 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   806 of the Axiom of Choice;
   807 
   808 
   809 
   810 New in Isabelle94-2
   811 -------------------
   812 
   813 * Significantly faster resolution;  
   814 
   815 * the different sections in a .thy file can now be mixed and repeated
   816 freely;
   817 
   818 * Database of theorems for FOL, HOL and ZF.  New
   819 commands including qed, qed_goal and bind_thm store theorems in the database.
   820 
   821 * Simple database queries: return a named theorem (get_thm) or all theorems of
   822 a given theory (thms_of), or find out what theory a theorem was proved in
   823 (theory_of_thm);
   824 
   825 * Bugs fixed in the inductive definition and datatype packages;
   826 
   827 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   828 and HOL_dup_cs obsolete;
   829 
   830 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   831 have been removed;
   832 
   833 * Simpler definition of function space in ZF;
   834 
   835 * new results about cardinal and ordinal arithmetic in ZF;
   836 
   837 * 'subtype' facility in HOL for introducing new types as subsets of existing
   838 types;
   839 
   840 
   841 $Id$