NEWS
author oheimb
Mon Oct 19 13:50:25 1998 +0200 (1998-10-19)
changeset 5671 da670b37857e
parent 5657 1a6c9c6a3f8e
child 5705 56f2030c46c6
permissions -rw-r--r--
layout
     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:
    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 semantics;
    57   addbefore now affects only the unsafe part of step_tac etc.;
    58   This affects addss/auto_tac/force_tac,so EXISTING (INSTABLE) PROOFS MAY FAIL,
    59   but proofs should be fixable easily, e.g. by replacing 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 'nonterminals' for purely syntactic types;
   109 
   110 * new theory section 'setup' for generic ML setup functions
   111 (e.g. package initialization);
   112 
   113 * the distribution now includes Isabelle icons: see
   114 lib/logo/isabelle-{small,tiny}.xpm;
   115 
   116 * isatool install - install binaries with absolute references to
   117 ISABELLE_HOME/bin;
   118 
   119 * isatool logo -- create instances of the Isabelle logo (as EPS);
   120 
   121 * print mode 'emacs' reserved for Isamode;
   122 
   123 
   124 *** HOL ***
   125 
   126 * HOL/inductive package reorganized and improved: now supports mutual
   127 definitions such as
   128 
   129   inductive EVEN ODD
   130     intrs
   131       null "0 : EVEN"
   132       oddI "n : EVEN ==> Suc n : ODD"
   133       evenI "n : ODD ==> Suc n : EVEN"
   134 
   135 new theorem list "elims" contains an elimination rule for each of the
   136 recursive sets; inductive definitions now handle disjunctive premises
   137 correctly (also ZF);
   138 
   139 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   140 "mutual_induct" no longer exists - the induction rule is always
   141 contained in "induct";
   142 
   143 
   144 * HOL/datatype package re-implemented and greatly improved: now
   145 supports mutually recursive datatypes such as
   146 
   147   datatype
   148     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   149             | SUM ('a aexp) ('a aexp)
   150             | DIFF ('a aexp) ('a aexp)
   151             | NUM 'a
   152   and
   153     'a bexp = LESS ('a aexp) ('a aexp)
   154             | AND ('a bexp) ('a bexp)
   155             | OR ('a bexp) ('a bexp)
   156 
   157 as well as indirectly recursive datatypes such as
   158 
   159   datatype
   160     ('a, 'b) term = Var 'a
   161                   | App 'b ((('a, 'b) term) list)
   162 
   163 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   164 induction on mutually / indirectly recursive datatypes.
   165 
   166 Primrec equations are now stored in theory and can be accessed via
   167 <function_name>.simps.
   168 
   169 INCOMPATIBILITIES:
   170 
   171   - Theories using datatypes must now have theory Datatype as an
   172     ancestor.
   173   - The specific <typename>.induct_tac no longer exists - use the
   174     generic induct_tac instead.
   175   - natE has been renamed to nat.exhaust - use exhaust_tac
   176     instead of res_inst_tac ... natE. Note that the variable
   177     names in nat.exhaust differ from the names in natE, this
   178     may cause some "fragile" proofs to fail.
   179   - The theorems split_<typename>_case and split_<typename>_case_asm
   180     have been renamed to <typename>.split and <typename>.split_asm.
   181   - Since default sorts of type variables are now handled correctly,
   182     some datatype definitions may have to be annotated with explicit
   183     sort constraints.
   184   - Primrec definitions no longer require function name and type
   185     of recursive argument.
   186 
   187 Consider using isatool fixdatatype to adapt your theories and proof
   188 scripts to the new package (backup your sources first!).
   189 
   190 
   191 * HOL/record package: now includes concrete syntax for record types,
   192 terms, updates; still lacks important theorems, like surjective
   193 pairing and split;
   194 
   195 * reorganized the main HOL image: HOL/Integ and String loaded by
   196 default; theory Main includes everything;
   197 
   198 * automatic simplification of integer sums and comparisons, using cancellation;
   199 
   200 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   201 
   202 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   203 
   204 * many new identities for unions, intersections, set difference, etc.;
   205 
   206 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   207 called split_if, split_split, split_sum_case and split_nat_case (to go
   208 with add/delsplits);
   209 
   210 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   211 (?x::unit) = (); this is made part of the default simpset, which COULD
   212 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   213 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   214 unit_abs_eta_conv is added in order to counter the effect of
   215 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   216 %u.f();
   217 
   218 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   219 makes more sense);
   220 
   221 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   222   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   223   disjointness reasoning but breaking a few old proofs.
   224 
   225 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   226 to 'converse' from 'inverse' (for compatibility with ZF and some
   227 literature);
   228 
   229 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   230 the well-founded relation;
   231 
   232 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   233     Compl A.  The "Compl" syntax remains available as input syntax for this
   234     release ONLY.
   235 
   236 * HOL/Update: new theory of function updates:
   237     f(a:=b) == %x. if x=a then b else f x
   238 may also be iterated as in f(a:=b,c:=d,...);
   239 
   240 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   241 
   242 * HOL/List:
   243   - new function list_update written xs[i:=v] that updates the i-th
   244     list position. May also be iterated as in xs[i:=a,j:=b,...].
   245   - new function `upt' written [i..j(] which generates the list
   246     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   247     bound write [i..j], which is a shorthand for [i..j+1(].
   248   - new lexicographic orderings and corresponding wellfoundedness theorems.
   249 
   250 * HOL/Arith:
   251   - removed 'pred' (predecessor) function;
   252   - generalized some theorems about n-1;
   253   - many new laws about "div" and "mod";
   254   - new laws about greatest common divisors (see theory ex/Primes);
   255 
   256 * HOL/Relation: renamed the relational operator r^-1 "converse"
   257 instead of "inverse";
   258 
   259 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   260   of the multiset ordering;
   261 
   262 * directory HOL/Real: a construction of the reals using Dedekind cuts
   263   (not included by default);
   264 
   265 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   266 
   267 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   268   programs, i.e. different program variables may have different types.
   269 
   270 * calling (stac rew i) now fails if "rew" has no effect on the goal
   271   [previously, this check worked only if the rewrite rule was unconditional]
   272   Now rew can involve either definitions or equalities (either == or =).
   273 
   274 
   275 *** ZF ***
   276 
   277 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   278   only the theorems proved on ZF.ML;
   279 
   280 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   281   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   282   disjointness reasoning but breaking a few old proofs.
   283 
   284 * ZF/Update: new theory of function updates
   285     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   286   may also be iterated as in f(a:=b,c:=d,...);
   287 
   288 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   289 
   290 * calling (stac rew i) now fails if "rew" has no effect on the goal
   291   [previously, this check worked only if the rewrite rule was unconditional]
   292   Now rew can involve either definitions or equalities (either == or =).
   293 
   294 * case_tac provided for compatibility with HOL
   295     (like the old excluded_middle_tac, but with subgoals swapped)
   296 
   297 
   298 *** Internal programming interfaces ***
   299 
   300 * Pure: several new basic modules made available for general use, see
   301 also src/Pure/README;
   302 
   303 * improved the theory data mechanism to support encapsulation (data
   304 kind name replaced by private Object.kind, acting as authorization
   305 key); new type-safe user interface via functor TheoryDataFun; generic
   306 print_data function becomes basically useless;
   307 
   308 * removed global_names compatibility flag -- all theory declarations
   309 are qualified by default;
   310 
   311 * module Pure/Syntax now offers quote / antiquote translation
   312 functions (useful for Hoare logic etc. with implicit dependencies);
   313 see HOL/ex/Antiquote for an example use;
   314 
   315 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   316 cterm -> thm;
   317 
   318 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   319 subgoal;
   320 
   321 * Display.print_goals function moved to Locale.print_goals;
   322 
   323 
   324 
   325 New in Isabelle98 (January 1998)
   326 --------------------------------
   327 
   328 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   329 
   330 * changed lexical syntax of terms / types: dots made part of long
   331 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   332 
   333 * simpset (and claset) reference variable replaced by functions
   334 simpset / simpset_ref;
   335 
   336 * no longer supports theory aliases (via merge) and non-trivial
   337 implicit merge of thms' signatures;
   338 
   339 * most internal names of constants changed due to qualified names;
   340 
   341 * changed Pure/Sequence interface (see Pure/seq.ML);
   342 
   343 
   344 *** General Changes ***
   345 
   346 * hierachically structured name spaces (for consts, types, axms, thms
   347 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   348 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   349 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   350 long_names for fully qualified output names; NOTE: ML programs
   351 (special tactics, packages etc.) referring to internal names may have
   352 to be adapted to cope with fully qualified names; in case of severe
   353 backward campatibility problems try setting 'global_names' at compile
   354 time to have enrything declared within a flat name space; one may also
   355 fine tune name declarations in theories via the 'global' and 'local'
   356 section;
   357 
   358 * reimplemented the implicit simpset and claset using the new anytype
   359 data filed in signatures; references simpset:simpset ref etc. are
   360 replaced by functions simpset:unit->simpset and
   361 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   362 to patch your ML files accordingly;
   363 
   364 * HTML output now includes theory graph data for display with Java
   365 applet or isatool browser; data generated automatically via isatool
   366 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   367 
   368 * defs may now be conditional; improved rewrite_goals_tac to handle
   369 conditional equations;
   370 
   371 * defs now admits additional type arguments, using TYPE('a) syntax;
   372 
   373 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   374 creates a new theory node; implicit merge of thms' signatures is
   375 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   376 transfer:theory->thm->thm in (rare) cases;
   377 
   378 * improved handling of draft signatures / theories; draft thms (and
   379 ctyps, cterms) are automatically promoted to real ones;
   380 
   381 * slightly changed interfaces for oracles: admit many per theory, named
   382 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   383 
   384 * print_goals: optional output of const types (set show_consts and
   385 show_types);
   386 
   387 * improved output of warnings (###) and errors (***);
   388 
   389 * subgoal_tac displays a warning if the new subgoal has type variables;
   390 
   391 * removed old README and Makefiles;
   392 
   393 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   394 
   395 * removed obsolete init_pps and init_database;
   396 
   397 * deleted the obsolete tactical STATE, which was declared by
   398     fun STATE tacfun st = tacfun st st;
   399 
   400 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   401 (which abbreviates $HOME);
   402 
   403 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   404 use isatool fixseq to adapt your ML programs (this works for fully
   405 qualified references to the Sequence structure only!);
   406 
   407 * use_thy no longer requires writable current directory; it always
   408 reloads .ML *and* .thy file, if either one is out of date;
   409 
   410 
   411 *** Classical Reasoner ***
   412 
   413 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   414 tactics that use classical reasoning to simplify a subgoal without
   415 splitting it into several subgoals;
   416 
   417 * Safe_tac: like safe_tac but uses the default claset;
   418 
   419 
   420 *** Simplifier ***
   421 
   422 * added simplification meta rules:
   423     (asm_)(full_)simplify: simpset -> thm -> thm;
   424 
   425 * simplifier.ML no longer part of Pure -- has to be loaded by object
   426 logics (again);
   427 
   428 * added prems argument to simplification procedures;
   429 
   430 * HOL, FOL, ZF: added infix function `addsplits':
   431   instead of `<simpset> setloop (split_tac <thms>)'
   432   you can simply write `<simpset> addsplits <thms>'
   433 
   434 
   435 *** Syntax ***
   436 
   437 * TYPE('a) syntax for type reflection terms;
   438 
   439 * no longer handles consts with name "" -- declare as 'syntax' instead;
   440 
   441 * pretty printer: changed order of mixfix annotation preference (again!);
   442 
   443 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   444 
   445 
   446 *** HOL ***
   447 
   448 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   449   with `addloop' of the simplifier to faciliate case splitting in premises.
   450 
   451 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   452 
   453 * HOL/Auth: new protocol proofs including some for the Internet
   454   protocol TLS;
   455 
   456 * HOL/Map: new theory of `maps' a la VDM;
   457 
   458 * HOL/simplifier: simplification procedures nat_cancel_sums for
   459 cancelling out common nat summands from =, <, <= (in)equalities, or
   460 differences; simplification procedures nat_cancel_factor for
   461 cancelling common factor from =, <, <= (in)equalities over natural
   462 sums; nat_cancel contains both kinds of procedures, it is installed by
   463 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   464 
   465 * HOL/simplifier: terms of the form
   466   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   467   are rewritten to
   468   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   469   and those of the form
   470   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   471   are rewritten to
   472   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   473 
   474 * HOL/datatype
   475   Each datatype `t' now comes with a theorem `split_t_case' of the form
   476 
   477   P(t_case f1 ... fn x) =
   478      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   479         ...
   480        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   481      )
   482 
   483   and a theorem `split_t_case_asm' of the form
   484 
   485   P(t_case f1 ... fn x) =
   486     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   487         ...
   488        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   489      )
   490   which can be added to a simpset via `addsplits'. The existing theorems
   491   expand_list_case and expand_option_case have been renamed to
   492   split_list_case and split_option_case.
   493 
   494 * HOL/Arithmetic:
   495   - `pred n' is automatically converted to `n-1'.
   496     Users are strongly encouraged not to use `pred' any longer,
   497     because it will disappear altogether at some point.
   498   - Users are strongly encouraged to write "0 < n" rather than
   499     "n ~= 0". Theorems and proof tools have been modified towards this
   500     `standard'.
   501 
   502 * HOL/Lists:
   503   the function "set_of_list" has been renamed "set" (and its theorems too);
   504   the function "nth" now takes its arguments in the reverse order and
   505   has acquired the infix notation "!" as in "xs!n".
   506 
   507 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   508 
   509 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   510   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   511 
   512 * HOL/record: extensible records with schematic structural subtyping
   513 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   514 still lacks various theorems and concrete record syntax;
   515 
   516 
   517 *** HOLCF ***
   518 
   519 * removed "axioms" and "generated by" sections;
   520 
   521 * replaced "ops" section by extended "consts" section, which is capable of
   522   handling the continuous function space "->" directly;
   523 
   524 * domain package:
   525   . proves theorems immediately and stores them in the theory,
   526   . creates hierachical name space,
   527   . now uses normal mixfix annotations (instead of cinfix...),
   528   . minor changes to some names and values (for consistency),
   529   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   530   . separator between mutual domain defs: changed "," to "and",
   531   . improved handling of sort constraints;  now they have to
   532     appear on the left-hand side of the equations only;
   533 
   534 * fixed LAM <x,y,zs>.b syntax;
   535 
   536 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   537 adm (%x. P (t x)), where P is chainfinite and t continuous;
   538 
   539 
   540 *** FOL and ZF ***
   541 
   542 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   543   with `addloop' of the simplifier to faciliate case splitting in premises.
   544 
   545 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   546 in HOL, they strip ALL and --> from proved theorems;
   547 
   548 
   549 
   550 New in Isabelle94-8 (May 1997)
   551 ------------------------------
   552 
   553 *** General Changes ***
   554 
   555 * new utilities to build / run / maintain Isabelle etc. (in parts
   556 still somewhat experimental); old Makefiles etc. still functional;
   557 
   558 * new 'Isabelle System Manual';
   559 
   560 * INSTALL text, together with ./configure and ./build scripts;
   561 
   562 * reimplemented type inference for greater efficiency, better error
   563 messages and clean internal interface;
   564 
   565 * prlim command for dealing with lots of subgoals (an easier way of
   566 setting goals_limit);
   567 
   568 
   569 *** Syntax ***
   570 
   571 * supports alternative (named) syntax tables (parser and pretty
   572 printer); internal interface is provided by add_modesyntax(_i);
   573 
   574 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   575 be used in conjunction with the Isabelle symbol font; uses the
   576 "symbols" syntax table;
   577 
   578 * added token_translation interface (may translate name tokens in
   579 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   580 the current print_mode); IMPORTANT: user print translation functions
   581 are responsible for marking newly introduced bounds
   582 (Syntax.mark_boundT);
   583 
   584 * token translations for modes "xterm" and "xterm_color" that display
   585 names in bold, underline etc. or colors (which requires a color
   586 version of xterm);
   587 
   588 * infixes may now be declared with names independent of their syntax;
   589 
   590 * added typed_print_translation (like print_translation, but may
   591 access type of constant);
   592 
   593 
   594 *** Classical Reasoner ***
   595 
   596 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   597 some limitations.  Blast_tac...
   598   + ignores addss, addbefore, addafter; this restriction is intrinsic
   599   + ignores elimination rules that don't have the correct format
   600 	(the conclusion MUST be a formula variable)
   601   + ignores types, which can make HOL proofs fail
   602   + rules must not require higher-order unification, e.g. apply_type in ZF
   603     [message "Function Var's argument not a bound variable" relates to this]
   604   + its proof strategy is more general but can actually be slower
   605 
   606 * substitution with equality assumptions no longer permutes other
   607 assumptions;
   608 
   609 * minor changes in semantics of addafter (now called addaltern); renamed
   610 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   611 (and access functions for it);
   612 
   613 * improved combination of classical reasoner and simplifier: 
   614   + functions for handling clasimpsets
   615   + improvement of addss: now the simplifier is called _after_ the
   616     safe steps.
   617   + safe variant of addss called addSss: uses safe simplifications
   618     _during_ the safe steps. It is more complete as it allows multiple 
   619     instantiations of unknowns (e.g. with slow_tac).
   620 
   621 *** Simplifier ***
   622 
   623 * added interface for simplification procedures (functions that
   624 produce *proven* rewrite rules on the fly, depending on current
   625 redex);
   626 
   627 * ordering on terms as parameter (used for ordered rewriting);
   628 
   629 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   630 
   631 * the solver is now split into a safe and an unsafe part.
   632 This should be invisible for the normal user, except that the
   633 functions setsolver and addsolver have been renamed to setSolver and
   634 addSolver; added safe_asm_full_simp_tac;
   635 
   636 
   637 *** HOL ***
   638 
   639 * a generic induction tactic `induct_tac' which works for all datatypes and
   640 also for type `nat';
   641 
   642 * a generic case distinction tactic `exhaust_tac' which works for all
   643 datatypes and also for type `nat';
   644 
   645 * each datatype comes with a function `size';
   646 
   647 * patterns in case expressions allow tuple patterns as arguments to
   648 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   649 
   650 * primrec now also works with type nat;
   651 
   652 * recdef: a new declaration form, allows general recursive functions to be
   653 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   654 
   655 * the constant for negation has been renamed from "not" to "Not" to
   656 harmonize with FOL, ZF, LK, etc.;
   657 
   658 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   659 infinite lists;
   660 
   661 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   662 
   663 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   664 problems in commutative rings, using axiomatic type classes for + and *;
   665 
   666 * more examples in HOL/MiniML and HOL/Auth;
   667 
   668 * more default rewrite rules for quantifiers, union/intersection;
   669 
   670 * a new constant `arbitrary == @x.False';
   671 
   672 * HOLCF/IOA replaces old HOL/IOA;
   673 
   674 * HOLCF changes: derived all rules and arities 
   675   + axiomatic type classes instead of classes 
   676   + typedef instead of faking type definitions
   677   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   678   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   679   + eliminated the types void, one, tr
   680   + use unit lift and bool lift (with translations) instead of one and tr
   681   + eliminated blift from Lift3.thy (use Def instead of blift)
   682   all eliminated rules are derived as theorems --> no visible changes ;
   683 
   684 
   685 *** ZF ***
   686 
   687 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   688 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   689 as ZF_cs addSIs [equalityI];
   690 
   691 
   692 
   693 New in Isabelle94-7 (November 96)
   694 ---------------------------------
   695 
   696 * allowing negative levels (as offsets) in prlev and choplev;
   697 
   698 * super-linear speedup for large simplifications;
   699 
   700 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   701 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   702 FAIL); can suppress it using the command Delsimps (ex_simps @
   703 all_simps); De Morgan laws are also now included, by default;
   704 
   705 * improved printing of ==>  :  ~:
   706 
   707 * new object-logic "Sequents" adds linear logic, while replacing LK
   708 and Modal (thanks to Sara Kalvala);
   709 
   710 * HOL/Auth: correctness proofs for authentication protocols;
   711 
   712 * HOL: new auto_tac combines rewriting and classical reasoning (many
   713 examples on HOL/Auth);
   714 
   715 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   716 the rewriter and classical reasoner simultaneously;
   717 
   718 * function uresult no longer returns theorems in "standard" format;
   719 regain previous version by: val uresult = standard o uresult;
   720 
   721 
   722 
   723 New in Isabelle94-6
   724 -------------------
   725 
   726 * oracles -- these establish an interface between Isabelle and trusted
   727 external reasoners, which may deliver results as theorems;
   728 
   729 * proof objects (in particular record all uses of oracles);
   730 
   731 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   732 
   733 * "constdefs" section in theory files;
   734 
   735 * "primrec" section (HOL) no longer requires names;
   736 
   737 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   738 
   739 
   740 
   741 New in Isabelle94-5
   742 -------------------
   743 
   744 * reduced space requirements;
   745 
   746 * automatic HTML generation from theories;
   747 
   748 * theory files no longer require "..." (quotes) around most types;
   749 
   750 * new examples, including two proofs of the Church-Rosser theorem;
   751 
   752 * non-curried (1994) version of HOL is no longer distributed;
   753 
   754 
   755 
   756 New in Isabelle94-4
   757 -------------------
   758 
   759 * greatly reduced space requirements;
   760 
   761 * theory files (.thy) no longer require \...\ escapes at line breaks;
   762 
   763 * searchable theorem database (see the section "Retrieving theorems" on 
   764 page 8 of the Reference Manual);
   765 
   766 * new examples, including Grabczewski's monumental case study of the
   767 Axiom of Choice;
   768 
   769 * The previous version of HOL renamed to Old_HOL;
   770 
   771 * The new version of HOL (previously called CHOL) uses a curried syntax 
   772 for functions.  Application looks like f a b instead of f(a,b);
   773 
   774 * Mutually recursive inductive definitions finally work in HOL;
   775 
   776 * In ZF, pattern-matching on tuples is now available in all abstractions and
   777 translates to the operator "split";
   778 
   779 
   780 
   781 New in Isabelle94-3
   782 -------------------
   783 
   784 * new infix operator, addss, allowing the classical reasoner to 
   785 perform simplification at each step of its search.  Example:
   786 	fast_tac (cs addss ss)
   787 
   788 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   789 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   790 look like (a,b) instead of <a,b>;
   791 
   792 * PLEASE NOTE: CHOL will eventually replace HOL!
   793 
   794 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   795 It translates to the operator "split".  A new theory of integers is available;
   796 
   797 * In ZF, integer numerals now denote two's-complement binary integers.
   798 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   799 
   800 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   801 of the Axiom of Choice;
   802 
   803 
   804 
   805 New in Isabelle94-2
   806 -------------------
   807 
   808 * Significantly faster resolution;  
   809 
   810 * the different sections in a .thy file can now be mixed and repeated
   811 freely;
   812 
   813 * Database of theorems for FOL, HOL and ZF.  New
   814 commands including qed, qed_goal and bind_thm store theorems in the database.
   815 
   816 * Simple database queries: return a named theorem (get_thm) or all theorems of
   817 a given theory (thms_of), or find out what theory a theorem was proved in
   818 (theory_of_thm);
   819 
   820 * Bugs fixed in the inductive definition and datatype packages;
   821 
   822 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   823 and HOL_dup_cs obsolete;
   824 
   825 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   826 have been removed;
   827 
   828 * Simpler definition of function space in ZF;
   829 
   830 * new results about cardinal and ordinal arithmetic in ZF;
   831 
   832 * 'subtype' facility in HOL for introducing new types as subsets of existing
   833 types;
   834 
   835 
   836 $Id$