NEWS
author wenzelm
Tue Dec 01 14:46:35 1998 +0100 (1998-12-01)
changeset 6000 aa84c30c1f61
parent 5973 040f6d2af50d
child 6014 bfd4923b0957
permissions -rw-r--r--
show_tags flag;
     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 * HOL: Removed the obsolete syntax "Compl A"; use -A for set complement
    11 
    12 
    13 *** Internal programming interfaces ***
    14 
    15 * tuned current_goals_markers semantics: begin / end goal avoids
    16 printing empty lines;
    17 
    18 * removed prs and prs_fn hook, which was broken because it did not
    19 include \n in its semantics, forcing writeln to add one
    20 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
    21 string -> unit if you really want to output text without newline;
    22 
    23 
    24 New in Isabelle98-1 (October 1998)
    25 ----------------------------------
    26 
    27 *** Overview of INCOMPATIBILITIES (see below for more details) ***
    28 
    29 * several changes of automated proof tools;
    30 
    31 * HOL: major changes to the inductive and datatype packages, including
    32 some minor incompatibilities of theory syntax;
    33 
    34 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
    35 called `inj_on';
    36 
    37 * HOL: removed duplicate thms in Arith:
    38   less_imp_add_less  should be replaced by  trans_less_add1
    39   le_imp_add_le      should be replaced by  trans_le_add1
    40 
    41 * HOL: unary minus is now overloaded (new type constraints may be
    42 required);
    43 
    44 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
    45 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
    46 now taken as an integer constant.
    47 
    48 * Pure: ML function 'theory_of' renamed to 'theory';
    49 
    50 
    51 *** Proof tools ***
    52 
    53 * Simplifier:
    54   1. Asm_full_simp_tac is now more aggressive.
    55      1. It will sometimes reorient premises if that increases their power to
    56         simplify.
    57      2. It does no longer proceed strictly from left to right but may also
    58         rotate premises to achieve further simplification.
    59      For compatibility reasons there is now Asm_lr_simp_tac which is like the
    60      old Asm_full_simp_tac in that it does not rotate premises.
    61   2. The simplifier now knows a little bit about nat-arithmetic.
    62 
    63 * Classical reasoner: wrapper mechanism for the classical reasoner now
    64 allows for selected deletion of wrappers, by introduction of names for
    65 wrapper functionals.  This implies that addbefore, addSbefore,
    66 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    67 and that adding two tactics with the same name overwrites the first
    68 one (emitting a warning).
    69   type wrapper = (int -> tactic) -> (int -> tactic)
    70   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    71   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    72   delWrapper, delSWrapper: claset *  string            -> claset
    73   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    74 
    75 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
    76 semantics; addbefore now affects only the unsafe part of step_tac
    77 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
    78 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
    79 by Force_tac;
    80 
    81 * Classical reasoner: setwrapper to setWrapper and compwrapper to
    82 compWrapper; added safe wrapper (and access functions for it);
    83 
    84 * HOL/split_all_tac is now much faster and fails if there is nothing
    85 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
    86 and the names of the automatically generated variables have changed.
    87 split_all_tac has moved within claset() from unsafe wrappers to safe
    88 wrappers, which means that !!-bound variables are split much more
    89 aggressively, and safe_tac and clarify_tac now split such variables.
    90 If this splitting is not appropriate, use delSWrapper "split_all_tac".
    91 Note: the same holds for record_split_tac, which does the job of
    92 split_all_tac for record fields.
    93 
    94 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
    95 permanently to the default simpset using Addsplits just like
    96 Addsimps. They can be removed via Delsplits just like
    97 Delsimps. Lower-case versions are also available.
    98 
    99 * HOL/Simplifier: The rule split_if is now part of the default
   100 simpset. This means that the simplifier will eliminate all occurrences
   101 of if-then-else in the conclusion of a goal. To prevent this, you can
   102 either remove split_if completely from the default simpset by
   103 `Delsplits [split_if]' or remove it in a specific call of the
   104 simplifier using `... delsplits [split_if]'.  You can also add/delete
   105 other case splitting rules to/from the default simpset: every datatype
   106 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   107 t is the name of the datatype).
   108 
   109 * Classical reasoner / Simplifier combination: new force_tac (and
   110 derivatives Force_tac, force) combines rewriting and classical
   111 reasoning (and whatever other tools) similarly to auto_tac, but is
   112 aimed to solve the given subgoal completely.
   113 
   114 
   115 *** General ***
   116 
   117 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   118 and `goalw': the theory is no longer needed as an explicit argument -
   119 the current theory context is used; assumptions are no longer returned
   120 at the ML-level unless one of them starts with ==> or !!; it is
   121 recommended to convert to these new commands using isatool fixgoal
   122 (backup your sources first!);
   123 
   124 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   125 the current theory context, and 'theory' to lookup stored theories;
   126 
   127 * new theory section 'locale' for declaring constants, assumptions and
   128 definitions that have local scope;
   129 
   130 * new theory section 'nonterminals' for purely syntactic types;
   131 
   132 * new theory section 'setup' for generic ML setup functions
   133 (e.g. package initialization);
   134 
   135 * the distribution now includes Isabelle icons: see
   136 lib/logo/isabelle-{small,tiny}.xpm;
   137 
   138 * isatool install - install binaries with absolute references to
   139 ISABELLE_HOME/bin;
   140 
   141 * isatool logo -- create instances of the Isabelle logo (as EPS);
   142 
   143 * print mode 'emacs' reserved for Isamode;
   144 
   145 * support multiple print (ast) translations per constant name;
   146 
   147 
   148 *** HOL ***
   149 
   150 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   151 
   152 * HOL/inductive package reorganized and improved: now supports mutual
   153 definitions such as
   154 
   155   inductive EVEN ODD
   156     intrs
   157       null "0 : EVEN"
   158       oddI "n : EVEN ==> Suc n : ODD"
   159       evenI "n : ODD ==> Suc n : EVEN"
   160 
   161 new theorem list "elims" contains an elimination rule for each of the
   162 recursive sets; inductive definitions now handle disjunctive premises
   163 correctly (also ZF);
   164 
   165 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   166 "mutual_induct" no longer exists - the induction rule is always
   167 contained in "induct";
   168 
   169 
   170 * HOL/datatype package re-implemented and greatly improved: now
   171 supports mutually recursive datatypes such as
   172 
   173   datatype
   174     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   175             | SUM ('a aexp) ('a aexp)
   176             | DIFF ('a aexp) ('a aexp)
   177             | NUM 'a
   178   and
   179     'a bexp = LESS ('a aexp) ('a aexp)
   180             | AND ('a bexp) ('a bexp)
   181             | OR ('a bexp) ('a bexp)
   182 
   183 as well as indirectly recursive datatypes such as
   184 
   185   datatype
   186     ('a, 'b) term = Var 'a
   187                   | App 'b ((('a, 'b) term) list)
   188 
   189 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   190 induction on mutually / indirectly recursive datatypes.
   191 
   192 Primrec equations are now stored in theory and can be accessed via
   193 <function_name>.simps.
   194 
   195 INCOMPATIBILITIES:
   196 
   197   - Theories using datatypes must now have theory Datatype as an
   198     ancestor.
   199   - The specific <typename>.induct_tac no longer exists - use the
   200     generic induct_tac instead.
   201   - natE has been renamed to nat.exhaust - use exhaust_tac
   202     instead of res_inst_tac ... natE. Note that the variable
   203     names in nat.exhaust differ from the names in natE, this
   204     may cause some "fragile" proofs to fail.
   205   - The theorems split_<typename>_case and split_<typename>_case_asm
   206     have been renamed to <typename>.split and <typename>.split_asm.
   207   - Since default sorts of type variables are now handled correctly,
   208     some datatype definitions may have to be annotated with explicit
   209     sort constraints.
   210   - Primrec definitions no longer require function name and type
   211     of recursive argument.
   212 
   213 Consider using isatool fixdatatype to adapt your theories and proof
   214 scripts to the new package (backup your sources first!).
   215 
   216 
   217 * HOL/record package: considerably improved implementation; now
   218 includes concrete syntax for record types, terms, updates; theorems
   219 for surjective pairing and splitting !!-bound record variables; proof
   220 support is as follows:
   221 
   222   1) standard conversions (selectors or updates applied to record
   223 constructor terms) are part of the standard simpset;
   224 
   225   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   226 made part of standard simpset and claset via addIffs;
   227 
   228   3) a tactic for record field splitting (record_split_tac) is part of
   229 the standard claset (addSWrapper);
   230 
   231 To get a better idea about these rules you may retrieve them via
   232 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   233 the name of your record type.
   234 
   235 The split tactic 3) conceptually simplifies by the following rule:
   236 
   237   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   238 
   239 Thus any record variable that is bound by meta-all will automatically
   240 blow up into some record constructor term, consequently the
   241 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   242 solve record problems automatically.
   243 
   244 
   245 * reorganized the main HOL image: HOL/Integ and String loaded by
   246 default; theory Main includes everything;
   247 
   248 * automatic simplification of integer sums and comparisons, using cancellation;
   249 
   250 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   251 
   252 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   253 
   254 * many new identities for unions, intersections, set difference, etc.;
   255 
   256 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   257 called split_if, split_split, split_sum_case and split_nat_case (to go
   258 with add/delsplits);
   259 
   260 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   261 (?x::unit) = (); this is made part of the default simpset, which COULD
   262 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   263 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   264 unit_abs_eta_conv is added in order to counter the effect of
   265 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   266 %u.f();
   267 
   268 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   269 makes more sense);
   270 
   271 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   272   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   273   disjointness reasoning but breaking a few old proofs.
   274 
   275 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   276 to 'converse' from 'inverse' (for compatibility with ZF and some
   277 literature);
   278 
   279 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   280 the well-founded relation;
   281 
   282 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   283     Compl A.  The "Compl" syntax remains available as input syntax for this
   284     release ONLY.
   285 
   286 * HOL/Update: new theory of function updates:
   287     f(a:=b) == %x. if x=a then b else f x
   288 may also be iterated as in f(a:=b,c:=d,...);
   289 
   290 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   291 
   292 * HOL/List:
   293   - new function list_update written xs[i:=v] that updates the i-th
   294     list position. May also be iterated as in xs[i:=a,j:=b,...].
   295   - new function `upt' written [i..j(] which generates the list
   296     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   297     bound write [i..j], which is a shorthand for [i..j+1(].
   298   - new lexicographic orderings and corresponding wellfoundedness theorems.
   299 
   300 * HOL/Arith:
   301   - removed 'pred' (predecessor) function;
   302   - generalized some theorems about n-1;
   303   - many new laws about "div" and "mod";
   304   - new laws about greatest common divisors (see theory ex/Primes);
   305 
   306 * HOL/Relation: renamed the relational operator r^-1 "converse"
   307 instead of "inverse";
   308 
   309 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   310   of the multiset ordering;
   311 
   312 * directory HOL/Real: a construction of the reals using Dedekind cuts
   313   (not included by default);
   314 
   315 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   316 
   317 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   318   programs, i.e. different program variables may have different types.
   319 
   320 * calling (stac rew i) now fails if "rew" has no effect on the goal
   321   [previously, this check worked only if the rewrite rule was unconditional]
   322   Now rew can involve either definitions or equalities (either == or =).
   323 
   324 
   325 *** ZF ***
   326 
   327 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   328   only the theorems proved on ZF.ML;
   329 
   330 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   331   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   332   disjointness reasoning but breaking a few old proofs.
   333 
   334 * ZF/Update: new theory of function updates
   335     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   336   may also be iterated as in f(a:=b,c:=d,...);
   337 
   338 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   339 
   340 * calling (stac rew i) now fails if "rew" has no effect on the goal
   341   [previously, this check worked only if the rewrite rule was unconditional]
   342   Now rew can involve either definitions or equalities (either == or =).
   343 
   344 * case_tac provided for compatibility with HOL
   345     (like the old excluded_middle_tac, but with subgoals swapped)
   346 
   347 
   348 *** Internal programming interfaces ***
   349 
   350 * Pure: several new basic modules made available for general use, see
   351 also src/Pure/README;
   352 
   353 * improved the theory data mechanism to support encapsulation (data
   354 kind name replaced by private Object.kind, acting as authorization
   355 key); new type-safe user interface via functor TheoryDataFun; generic
   356 print_data function becomes basically useless;
   357 
   358 * removed global_names compatibility flag -- all theory declarations
   359 are qualified by default;
   360 
   361 * module Pure/Syntax now offers quote / antiquote translation
   362 functions (useful for Hoare logic etc. with implicit dependencies);
   363 see HOL/ex/Antiquote for an example use;
   364 
   365 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   366 cterm -> thm;
   367 
   368 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   369 subgoal;
   370 
   371 * Display.print_goals function moved to Locale.print_goals;
   372 
   373 * standard print function for goals supports current_goals_markers
   374 variable for marking begin of proof, end of proof, start of goal; the
   375 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   376 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   377 for example;
   378 
   379 
   380 
   381 New in Isabelle98 (January 1998)
   382 --------------------------------
   383 
   384 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   385 
   386 * changed lexical syntax of terms / types: dots made part of long
   387 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   388 
   389 * simpset (and claset) reference variable replaced by functions
   390 simpset / simpset_ref;
   391 
   392 * no longer supports theory aliases (via merge) and non-trivial
   393 implicit merge of thms' signatures;
   394 
   395 * most internal names of constants changed due to qualified names;
   396 
   397 * changed Pure/Sequence interface (see Pure/seq.ML);
   398 
   399 
   400 *** General Changes ***
   401 
   402 * hierachically structured name spaces (for consts, types, axms, thms
   403 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   404 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   405 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   406 long_names for fully qualified output names; NOTE: ML programs
   407 (special tactics, packages etc.) referring to internal names may have
   408 to be adapted to cope with fully qualified names; in case of severe
   409 backward campatibility problems try setting 'global_names' at compile
   410 time to have enrything declared within a flat name space; one may also
   411 fine tune name declarations in theories via the 'global' and 'local'
   412 section;
   413 
   414 * reimplemented the implicit simpset and claset using the new anytype
   415 data filed in signatures; references simpset:simpset ref etc. are
   416 replaced by functions simpset:unit->simpset and
   417 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   418 to patch your ML files accordingly;
   419 
   420 * HTML output now includes theory graph data for display with Java
   421 applet or isatool browser; data generated automatically via isatool
   422 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   423 
   424 * defs may now be conditional; improved rewrite_goals_tac to handle
   425 conditional equations;
   426 
   427 * defs now admits additional type arguments, using TYPE('a) syntax;
   428 
   429 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   430 creates a new theory node; implicit merge of thms' signatures is
   431 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   432 transfer:theory->thm->thm in (rare) cases;
   433 
   434 * improved handling of draft signatures / theories; draft thms (and
   435 ctyps, cterms) are automatically promoted to real ones;
   436 
   437 * slightly changed interfaces for oracles: admit many per theory, named
   438 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   439 
   440 * print_goals: optional output of const types (set show_consts and
   441 show_types);
   442 
   443 * improved output of warnings (###) and errors (***);
   444 
   445 * subgoal_tac displays a warning if the new subgoal has type variables;
   446 
   447 * removed old README and Makefiles;
   448 
   449 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   450 
   451 * removed obsolete init_pps and init_database;
   452 
   453 * deleted the obsolete tactical STATE, which was declared by
   454     fun STATE tacfun st = tacfun st st;
   455 
   456 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   457 (which abbreviates $HOME);
   458 
   459 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   460 use isatool fixseq to adapt your ML programs (this works for fully
   461 qualified references to the Sequence structure only!);
   462 
   463 * use_thy no longer requires writable current directory; it always
   464 reloads .ML *and* .thy file, if either one is out of date;
   465 
   466 
   467 *** Classical Reasoner ***
   468 
   469 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   470 tactics that use classical reasoning to simplify a subgoal without
   471 splitting it into several subgoals;
   472 
   473 * Safe_tac: like safe_tac but uses the default claset;
   474 
   475 
   476 *** Simplifier ***
   477 
   478 * added simplification meta rules:
   479     (asm_)(full_)simplify: simpset -> thm -> thm;
   480 
   481 * simplifier.ML no longer part of Pure -- has to be loaded by object
   482 logics (again);
   483 
   484 * added prems argument to simplification procedures;
   485 
   486 * HOL, FOL, ZF: added infix function `addsplits':
   487   instead of `<simpset> setloop (split_tac <thms>)'
   488   you can simply write `<simpset> addsplits <thms>'
   489 
   490 
   491 *** Syntax ***
   492 
   493 * TYPE('a) syntax for type reflection terms;
   494 
   495 * no longer handles consts with name "" -- declare as 'syntax' instead;
   496 
   497 * pretty printer: changed order of mixfix annotation preference (again!);
   498 
   499 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   500 
   501 
   502 *** HOL ***
   503 
   504 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   505   with `addloop' of the simplifier to faciliate case splitting in premises.
   506 
   507 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   508 
   509 * HOL/Auth: new protocol proofs including some for the Internet
   510   protocol TLS;
   511 
   512 * HOL/Map: new theory of `maps' a la VDM;
   513 
   514 * HOL/simplifier: simplification procedures nat_cancel_sums for
   515 cancelling out common nat summands from =, <, <= (in)equalities, or
   516 differences; simplification procedures nat_cancel_factor for
   517 cancelling common factor from =, <, <= (in)equalities over natural
   518 sums; nat_cancel contains both kinds of procedures, it is installed by
   519 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   520 
   521 * HOL/simplifier: terms of the form
   522   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   523   are rewritten to
   524   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   525   and those of the form
   526   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   527   are rewritten to
   528   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   529 
   530 * HOL/datatype
   531   Each datatype `t' now comes with a theorem `split_t_case' of the form
   532 
   533   P(t_case f1 ... fn x) =
   534      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   535         ...
   536        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   537      )
   538 
   539   and a theorem `split_t_case_asm' of the form
   540 
   541   P(t_case f1 ... fn x) =
   542     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   543         ...
   544        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   545      )
   546   which can be added to a simpset via `addsplits'. The existing theorems
   547   expand_list_case and expand_option_case have been renamed to
   548   split_list_case and split_option_case.
   549 
   550 * HOL/Arithmetic:
   551   - `pred n' is automatically converted to `n-1'.
   552     Users are strongly encouraged not to use `pred' any longer,
   553     because it will disappear altogether at some point.
   554   - Users are strongly encouraged to write "0 < n" rather than
   555     "n ~= 0". Theorems and proof tools have been modified towards this
   556     `standard'.
   557 
   558 * HOL/Lists:
   559   the function "set_of_list" has been renamed "set" (and its theorems too);
   560   the function "nth" now takes its arguments in the reverse order and
   561   has acquired the infix notation "!" as in "xs!n".
   562 
   563 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   564 
   565 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   566   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   567 
   568 * HOL/record: extensible records with schematic structural subtyping
   569 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   570 still lacks various theorems and concrete record syntax;
   571 
   572 
   573 *** HOLCF ***
   574 
   575 * removed "axioms" and "generated by" sections;
   576 
   577 * replaced "ops" section by extended "consts" section, which is capable of
   578   handling the continuous function space "->" directly;
   579 
   580 * domain package:
   581   . proves theorems immediately and stores them in the theory,
   582   . creates hierachical name space,
   583   . now uses normal mixfix annotations (instead of cinfix...),
   584   . minor changes to some names and values (for consistency),
   585   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   586   . separator between mutual domain defs: changed "," to "and",
   587   . improved handling of sort constraints;  now they have to
   588     appear on the left-hand side of the equations only;
   589 
   590 * fixed LAM <x,y,zs>.b syntax;
   591 
   592 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   593 adm (%x. P (t x)), where P is chainfinite and t continuous;
   594 
   595 
   596 *** FOL and ZF ***
   597 
   598 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   599   with `addloop' of the simplifier to faciliate case splitting in premises.
   600 
   601 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   602 in HOL, they strip ALL and --> from proved theorems;
   603 
   604 
   605 
   606 New in Isabelle94-8 (May 1997)
   607 ------------------------------
   608 
   609 *** General Changes ***
   610 
   611 * new utilities to build / run / maintain Isabelle etc. (in parts
   612 still somewhat experimental); old Makefiles etc. still functional;
   613 
   614 * new 'Isabelle System Manual';
   615 
   616 * INSTALL text, together with ./configure and ./build scripts;
   617 
   618 * reimplemented type inference for greater efficiency, better error
   619 messages and clean internal interface;
   620 
   621 * prlim command for dealing with lots of subgoals (an easier way of
   622 setting goals_limit);
   623 
   624 
   625 *** Syntax ***
   626 
   627 * supports alternative (named) syntax tables (parser and pretty
   628 printer); internal interface is provided by add_modesyntax(_i);
   629 
   630 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   631 be used in conjunction with the Isabelle symbol font; uses the
   632 "symbols" syntax table;
   633 
   634 * added token_translation interface (may translate name tokens in
   635 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   636 the current print_mode); IMPORTANT: user print translation functions
   637 are responsible for marking newly introduced bounds
   638 (Syntax.mark_boundT);
   639 
   640 * token translations for modes "xterm" and "xterm_color" that display
   641 names in bold, underline etc. or colors (which requires a color
   642 version of xterm);
   643 
   644 * infixes may now be declared with names independent of their syntax;
   645 
   646 * added typed_print_translation (like print_translation, but may
   647 access type of constant);
   648 
   649 
   650 *** Classical Reasoner ***
   651 
   652 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   653 some limitations.  Blast_tac...
   654   + ignores addss, addbefore, addafter; this restriction is intrinsic
   655   + ignores elimination rules that don't have the correct format
   656         (the conclusion MUST be a formula variable)
   657   + ignores types, which can make HOL proofs fail
   658   + rules must not require higher-order unification, e.g. apply_type in ZF
   659     [message "Function Var's argument not a bound variable" relates to this]
   660   + its proof strategy is more general but can actually be slower
   661 
   662 * substitution with equality assumptions no longer permutes other
   663 assumptions;
   664 
   665 * minor changes in semantics of addafter (now called addaltern); renamed
   666 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   667 (and access functions for it);
   668 
   669 * improved combination of classical reasoner and simplifier:
   670   + functions for handling clasimpsets
   671   + improvement of addss: now the simplifier is called _after_ the
   672     safe steps.
   673   + safe variant of addss called addSss: uses safe simplifications
   674     _during_ the safe steps. It is more complete as it allows multiple
   675     instantiations of unknowns (e.g. with slow_tac).
   676 
   677 *** Simplifier ***
   678 
   679 * added interface for simplification procedures (functions that
   680 produce *proven* rewrite rules on the fly, depending on current
   681 redex);
   682 
   683 * ordering on terms as parameter (used for ordered rewriting);
   684 
   685 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   686 
   687 * the solver is now split into a safe and an unsafe part.
   688 This should be invisible for the normal user, except that the
   689 functions setsolver and addsolver have been renamed to setSolver and
   690 addSolver; added safe_asm_full_simp_tac;
   691 
   692 
   693 *** HOL ***
   694 
   695 * a generic induction tactic `induct_tac' which works for all datatypes and
   696 also for type `nat';
   697 
   698 * a generic case distinction tactic `exhaust_tac' which works for all
   699 datatypes and also for type `nat';
   700 
   701 * each datatype comes with a function `size';
   702 
   703 * patterns in case expressions allow tuple patterns as arguments to
   704 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   705 
   706 * primrec now also works with type nat;
   707 
   708 * recdef: a new declaration form, allows general recursive functions to be
   709 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   710 
   711 * the constant for negation has been renamed from "not" to "Not" to
   712 harmonize with FOL, ZF, LK, etc.;
   713 
   714 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   715 infinite lists;
   716 
   717 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   718 
   719 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   720 problems in commutative rings, using axiomatic type classes for + and *;
   721 
   722 * more examples in HOL/MiniML and HOL/Auth;
   723 
   724 * more default rewrite rules for quantifiers, union/intersection;
   725 
   726 * a new constant `arbitrary == @x.False';
   727 
   728 * HOLCF/IOA replaces old HOL/IOA;
   729 
   730 * HOLCF changes: derived all rules and arities
   731   + axiomatic type classes instead of classes
   732   + typedef instead of faking type definitions
   733   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   734   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   735   + eliminated the types void, one, tr
   736   + use unit lift and bool lift (with translations) instead of one and tr
   737   + eliminated blift from Lift3.thy (use Def instead of blift)
   738   all eliminated rules are derived as theorems --> no visible changes ;
   739 
   740 
   741 *** ZF ***
   742 
   743 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   744 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   745 as ZF_cs addSIs [equalityI];
   746 
   747 
   748 
   749 New in Isabelle94-7 (November 96)
   750 ---------------------------------
   751 
   752 * allowing negative levels (as offsets) in prlev and choplev;
   753 
   754 * super-linear speedup for large simplifications;
   755 
   756 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   757 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   758 FAIL); can suppress it using the command Delsimps (ex_simps @
   759 all_simps); De Morgan laws are also now included, by default;
   760 
   761 * improved printing of ==>  :  ~:
   762 
   763 * new object-logic "Sequents" adds linear logic, while replacing LK
   764 and Modal (thanks to Sara Kalvala);
   765 
   766 * HOL/Auth: correctness proofs for authentication protocols;
   767 
   768 * HOL: new auto_tac combines rewriting and classical reasoning (many
   769 examples on HOL/Auth);
   770 
   771 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   772 the rewriter and classical reasoner simultaneously;
   773 
   774 * function uresult no longer returns theorems in "standard" format;
   775 regain previous version by: val uresult = standard o uresult;
   776 
   777 
   778 
   779 New in Isabelle94-6
   780 -------------------
   781 
   782 * oracles -- these establish an interface between Isabelle and trusted
   783 external reasoners, which may deliver results as theorems;
   784 
   785 * proof objects (in particular record all uses of oracles);
   786 
   787 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   788 
   789 * "constdefs" section in theory files;
   790 
   791 * "primrec" section (HOL) no longer requires names;
   792 
   793 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   794 
   795 
   796 
   797 New in Isabelle94-5
   798 -------------------
   799 
   800 * reduced space requirements;
   801 
   802 * automatic HTML generation from theories;
   803 
   804 * theory files no longer require "..." (quotes) around most types;
   805 
   806 * new examples, including two proofs of the Church-Rosser theorem;
   807 
   808 * non-curried (1994) version of HOL is no longer distributed;
   809 
   810 
   811 
   812 New in Isabelle94-4
   813 -------------------
   814 
   815 * greatly reduced space requirements;
   816 
   817 * theory files (.thy) no longer require \...\ escapes at line breaks;
   818 
   819 * searchable theorem database (see the section "Retrieving theorems" on
   820 page 8 of the Reference Manual);
   821 
   822 * new examples, including Grabczewski's monumental case study of the
   823 Axiom of Choice;
   824 
   825 * The previous version of HOL renamed to Old_HOL;
   826 
   827 * The new version of HOL (previously called CHOL) uses a curried syntax
   828 for functions.  Application looks like f a b instead of f(a,b);
   829 
   830 * Mutually recursive inductive definitions finally work in HOL;
   831 
   832 * In ZF, pattern-matching on tuples is now available in all abstractions and
   833 translates to the operator "split";
   834 
   835 
   836 
   837 New in Isabelle94-3
   838 -------------------
   839 
   840 * new infix operator, addss, allowing the classical reasoner to
   841 perform simplification at each step of its search.  Example:
   842         fast_tac (cs addss ss)
   843 
   844 * a new logic, CHOL, the same as HOL, but with a curried syntax
   845 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
   846 look like (a,b) instead of <a,b>;
   847 
   848 * PLEASE NOTE: CHOL will eventually replace HOL!
   849 
   850 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   851 It translates to the operator "split".  A new theory of integers is available;
   852 
   853 * In ZF, integer numerals now denote two's-complement binary integers.
   854 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   855 
   856 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
   857 of the Axiom of Choice;
   858 
   859 
   860 
   861 New in Isabelle94-2
   862 -------------------
   863 
   864 * Significantly faster resolution;
   865 
   866 * the different sections in a .thy file can now be mixed and repeated
   867 freely;
   868 
   869 * Database of theorems for FOL, HOL and ZF.  New
   870 commands including qed, qed_goal and bind_thm store theorems in the database.
   871 
   872 * Simple database queries: return a named theorem (get_thm) or all theorems of
   873 a given theory (thms_of), or find out what theory a theorem was proved in
   874 (theory_of_thm);
   875 
   876 * Bugs fixed in the inductive definition and datatype packages;
   877 
   878 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   879 and HOL_dup_cs obsolete;
   880 
   881 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   882 have been removed;
   883 
   884 * Simpler definition of function space in ZF;
   885 
   886 * new results about cardinal and ordinal arithmetic in ZF;
   887 
   888 * 'subtype' facility in HOL for introducing new types as subsets of existing
   889 types;
   890 
   891 
   892 $Id$