NEWS
author paulson
Mon Dec 07 18:26:25 1998 +0100 (1998-12-07)
changeset 6019 0e55c2fb2ebb
parent 6014 bfd4923b0957
child 6028 1bfd52528bde
permissions -rw-r--r--
tidying
     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 *** General ***
    13 
    14 * in locales, the "assumes" and "defines" parts may be omitted if empty;
    15 
    16 *** Internal programming interfaces ***
    17 
    18 * tuned current_goals_markers semantics: begin / end goal avoids
    19 printing empty lines;
    20 
    21 * removed prs and prs_fn hook, which was broken because it did not
    22 include \n in its semantics, forcing writeln to add one
    23 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
    24 string -> unit if you really want to output text without newline;
    25 
    26 
    27 New in Isabelle98-1 (October 1998)
    28 ----------------------------------
    29 
    30 *** Overview of INCOMPATIBILITIES (see below for more details) ***
    31 
    32 * several changes of automated proof tools;
    33 
    34 * HOL: major changes to the inductive and datatype packages, including
    35 some minor incompatibilities of theory syntax;
    36 
    37 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
    38 called `inj_on';
    39 
    40 * HOL: removed duplicate thms in Arith:
    41   less_imp_add_less  should be replaced by  trans_less_add1
    42   le_imp_add_le      should be replaced by  trans_le_add1
    43 
    44 * HOL: unary minus is now overloaded (new type constraints may be
    45 required);
    46 
    47 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
    48 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
    49 now taken as an integer constant.
    50 
    51 * Pure: ML function 'theory_of' renamed to 'theory';
    52 
    53 
    54 *** Proof tools ***
    55 
    56 * Simplifier:
    57   1. Asm_full_simp_tac is now more aggressive.
    58      1. It will sometimes reorient premises if that increases their power to
    59         simplify.
    60      2. It does no longer proceed strictly from left to right but may also
    61         rotate premises to achieve further simplification.
    62      For compatibility reasons there is now Asm_lr_simp_tac which is like the
    63      old Asm_full_simp_tac in that it does not rotate premises.
    64   2. The simplifier now knows a little bit about nat-arithmetic.
    65 
    66 * Classical reasoner: wrapper mechanism for the classical reasoner now
    67 allows for selected deletion of wrappers, by introduction of names for
    68 wrapper functionals.  This implies that addbefore, addSbefore,
    69 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    70 and that adding two tactics with the same name overwrites the first
    71 one (emitting a warning).
    72   type wrapper = (int -> tactic) -> (int -> tactic)
    73   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    74   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    75   delWrapper, delSWrapper: claset *  string            -> claset
    76   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    77 
    78 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
    79 semantics; addbefore now affects only the unsafe part of step_tac
    80 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
    81 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
    82 by Force_tac;
    83 
    84 * Classical reasoner: setwrapper to setWrapper and compwrapper to
    85 compWrapper; added safe wrapper (and access functions for it);
    86 
    87 * HOL/split_all_tac is now much faster and fails if there is nothing
    88 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
    89 and the names of the automatically generated variables have changed.
    90 split_all_tac has moved within claset() from unsafe wrappers to safe
    91 wrappers, which means that !!-bound variables are split much more
    92 aggressively, and safe_tac and clarify_tac now split such variables.
    93 If this splitting is not appropriate, use delSWrapper "split_all_tac".
    94 Note: the same holds for record_split_tac, which does the job of
    95 split_all_tac for record fields.
    96 
    97 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
    98 permanently to the default simpset using Addsplits just like
    99 Addsimps. They can be removed via Delsplits just like
   100 Delsimps. Lower-case versions are also available.
   101 
   102 * HOL/Simplifier: The rule split_if is now part of the default
   103 simpset. This means that the simplifier will eliminate all occurrences
   104 of if-then-else in the conclusion of a goal. To prevent this, you can
   105 either remove split_if completely from the default simpset by
   106 `Delsplits [split_if]' or remove it in a specific call of the
   107 simplifier using `... delsplits [split_if]'.  You can also add/delete
   108 other case splitting rules to/from the default simpset: every datatype
   109 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   110 t is the name of the datatype).
   111 
   112 * Classical reasoner / Simplifier combination: new force_tac (and
   113 derivatives Force_tac, force) combines rewriting and classical
   114 reasoning (and whatever other tools) similarly to auto_tac, but is
   115 aimed to solve the given subgoal completely.
   116 
   117 
   118 *** General ***
   119 
   120 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   121 and `goalw': the theory is no longer needed as an explicit argument -
   122 the current theory context is used; assumptions are no longer returned
   123 at the ML-level unless one of them starts with ==> or !!; it is
   124 recommended to convert to these new commands using isatool fixgoal
   125 (backup your sources first!);
   126 
   127 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   128 the current theory context, and 'theory' to lookup stored theories;
   129 
   130 * new theory section 'locale' for declaring constants, assumptions and
   131 definitions that have local scope;
   132 
   133 * new theory section 'nonterminals' for purely syntactic types;
   134 
   135 * new theory section 'setup' for generic ML setup functions
   136 (e.g. package initialization);
   137 
   138 * the distribution now includes Isabelle icons: see
   139 lib/logo/isabelle-{small,tiny}.xpm;
   140 
   141 * isatool install - install binaries with absolute references to
   142 ISABELLE_HOME/bin;
   143 
   144 * isatool logo -- create instances of the Isabelle logo (as EPS);
   145 
   146 * print mode 'emacs' reserved for Isamode;
   147 
   148 * support multiple print (ast) translations per constant name;
   149 
   150 
   151 *** HOL ***
   152 
   153 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   154 
   155 * HOL/inductive package reorganized and improved: now supports mutual
   156 definitions such as
   157 
   158   inductive EVEN ODD
   159     intrs
   160       null "0 : EVEN"
   161       oddI "n : EVEN ==> Suc n : ODD"
   162       evenI "n : ODD ==> Suc n : EVEN"
   163 
   164 new theorem list "elims" contains an elimination rule for each of the
   165 recursive sets; inductive definitions now handle disjunctive premises
   166 correctly (also ZF);
   167 
   168 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   169 "mutual_induct" no longer exists - the induction rule is always
   170 contained in "induct";
   171 
   172 
   173 * HOL/datatype package re-implemented and greatly improved: now
   174 supports mutually recursive datatypes such as
   175 
   176   datatype
   177     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   178             | SUM ('a aexp) ('a aexp)
   179             | DIFF ('a aexp) ('a aexp)
   180             | NUM 'a
   181   and
   182     'a bexp = LESS ('a aexp) ('a aexp)
   183             | AND ('a bexp) ('a bexp)
   184             | OR ('a bexp) ('a bexp)
   185 
   186 as well as indirectly recursive datatypes such as
   187 
   188   datatype
   189     ('a, 'b) term = Var 'a
   190                   | App 'b ((('a, 'b) term) list)
   191 
   192 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   193 induction on mutually / indirectly recursive datatypes.
   194 
   195 Primrec equations are now stored in theory and can be accessed via
   196 <function_name>.simps.
   197 
   198 INCOMPATIBILITIES:
   199 
   200   - Theories using datatypes must now have theory Datatype as an
   201     ancestor.
   202   - The specific <typename>.induct_tac no longer exists - use the
   203     generic induct_tac instead.
   204   - natE has been renamed to nat.exhaust - use exhaust_tac
   205     instead of res_inst_tac ... natE. Note that the variable
   206     names in nat.exhaust differ from the names in natE, this
   207     may cause some "fragile" proofs to fail.
   208   - The theorems split_<typename>_case and split_<typename>_case_asm
   209     have been renamed to <typename>.split and <typename>.split_asm.
   210   - Since default sorts of type variables are now handled correctly,
   211     some datatype definitions may have to be annotated with explicit
   212     sort constraints.
   213   - Primrec definitions no longer require function name and type
   214     of recursive argument.
   215 
   216 Consider using isatool fixdatatype to adapt your theories and proof
   217 scripts to the new package (backup your sources first!).
   218 
   219 
   220 * HOL/record package: considerably improved implementation; now
   221 includes concrete syntax for record types, terms, updates; theorems
   222 for surjective pairing and splitting !!-bound record variables; proof
   223 support is as follows:
   224 
   225   1) standard conversions (selectors or updates applied to record
   226 constructor terms) are part of the standard simpset;
   227 
   228   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   229 made part of standard simpset and claset via addIffs;
   230 
   231   3) a tactic for record field splitting (record_split_tac) is part of
   232 the standard claset (addSWrapper);
   233 
   234 To get a better idea about these rules you may retrieve them via
   235 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   236 the name of your record type.
   237 
   238 The split tactic 3) conceptually simplifies by the following rule:
   239 
   240   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   241 
   242 Thus any record variable that is bound by meta-all will automatically
   243 blow up into some record constructor term, consequently the
   244 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   245 solve record problems automatically.
   246 
   247 
   248 * reorganized the main HOL image: HOL/Integ and String loaded by
   249 default; theory Main includes everything;
   250 
   251 * automatic simplification of integer sums and comparisons, using cancellation;
   252 
   253 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   254 
   255 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   256 
   257 * many new identities for unions, intersections, set difference, etc.;
   258 
   259 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   260 called split_if, split_split, split_sum_case and split_nat_case (to go
   261 with add/delsplits);
   262 
   263 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   264 (?x::unit) = (); this is made part of the default simpset, which COULD
   265 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   266 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   267 unit_abs_eta_conv is added in order to counter the effect of
   268 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   269 %u.f();
   270 
   271 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   272 makes more sense);
   273 
   274 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   275   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   276   disjointness reasoning but breaking a few old proofs.
   277 
   278 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   279 to 'converse' from 'inverse' (for compatibility with ZF and some
   280 literature);
   281 
   282 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   283 the well-founded relation;
   284 
   285 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   286     Compl A.  The "Compl" syntax remains available as input syntax for this
   287     release ONLY.
   288 
   289 * HOL/Update: new theory of function updates:
   290     f(a:=b) == %x. if x=a then b else f x
   291 may also be iterated as in f(a:=b,c:=d,...);
   292 
   293 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   294 
   295 * HOL/List:
   296   - new function list_update written xs[i:=v] that updates the i-th
   297     list position. May also be iterated as in xs[i:=a,j:=b,...].
   298   - new function `upt' written [i..j(] which generates the list
   299     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   300     bound write [i..j], which is a shorthand for [i..j+1(].
   301   - new lexicographic orderings and corresponding wellfoundedness theorems.
   302 
   303 * HOL/Arith:
   304   - removed 'pred' (predecessor) function;
   305   - generalized some theorems about n-1;
   306   - many new laws about "div" and "mod";
   307   - new laws about greatest common divisors (see theory ex/Primes);
   308 
   309 * HOL/Relation: renamed the relational operator r^-1 "converse"
   310 instead of "inverse";
   311 
   312 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   313   of the multiset ordering;
   314 
   315 * directory HOL/Real: a construction of the reals using Dedekind cuts
   316   (not included by default);
   317 
   318 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   319 
   320 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   321   programs, i.e. different program variables may have different types.
   322 
   323 * calling (stac rew i) now fails if "rew" has no effect on the goal
   324   [previously, this check worked only if the rewrite rule was unconditional]
   325   Now rew can involve either definitions or equalities (either == or =).
   326 
   327 
   328 *** ZF ***
   329 
   330 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   331   only the theorems proved on ZF.ML;
   332 
   333 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   334   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   335   disjointness reasoning but breaking a few old proofs.
   336 
   337 * ZF/Update: new theory of function updates
   338     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   339   may also be iterated as in f(a:=b,c:=d,...);
   340 
   341 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   342 
   343 * calling (stac rew i) now fails if "rew" has no effect on the goal
   344   [previously, this check worked only if the rewrite rule was unconditional]
   345   Now rew can involve either definitions or equalities (either == or =).
   346 
   347 * case_tac provided for compatibility with HOL
   348     (like the old excluded_middle_tac, but with subgoals swapped)
   349 
   350 
   351 *** Internal programming interfaces ***
   352 
   353 * Pure: several new basic modules made available for general use, see
   354 also src/Pure/README;
   355 
   356 * improved the theory data mechanism to support encapsulation (data
   357 kind name replaced by private Object.kind, acting as authorization
   358 key); new type-safe user interface via functor TheoryDataFun; generic
   359 print_data function becomes basically useless;
   360 
   361 * removed global_names compatibility flag -- all theory declarations
   362 are qualified by default;
   363 
   364 * module Pure/Syntax now offers quote / antiquote translation
   365 functions (useful for Hoare logic etc. with implicit dependencies);
   366 see HOL/ex/Antiquote for an example use;
   367 
   368 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   369 cterm -> thm;
   370 
   371 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   372 subgoal;
   373 
   374 * Display.print_goals function moved to Locale.print_goals;
   375 
   376 * standard print function for goals supports current_goals_markers
   377 variable for marking begin of proof, end of proof, start of goal; the
   378 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   379 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   380 for example;
   381 
   382 
   383 
   384 New in Isabelle98 (January 1998)
   385 --------------------------------
   386 
   387 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   388 
   389 * changed lexical syntax of terms / types: dots made part of long
   390 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   391 
   392 * simpset (and claset) reference variable replaced by functions
   393 simpset / simpset_ref;
   394 
   395 * no longer supports theory aliases (via merge) and non-trivial
   396 implicit merge of thms' signatures;
   397 
   398 * most internal names of constants changed due to qualified names;
   399 
   400 * changed Pure/Sequence interface (see Pure/seq.ML);
   401 
   402 
   403 *** General Changes ***
   404 
   405 * hierachically structured name spaces (for consts, types, axms, thms
   406 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   407 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   408 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   409 long_names for fully qualified output names; NOTE: ML programs
   410 (special tactics, packages etc.) referring to internal names may have
   411 to be adapted to cope with fully qualified names; in case of severe
   412 backward campatibility problems try setting 'global_names' at compile
   413 time to have enrything declared within a flat name space; one may also
   414 fine tune name declarations in theories via the 'global' and 'local'
   415 section;
   416 
   417 * reimplemented the implicit simpset and claset using the new anytype
   418 data filed in signatures; references simpset:simpset ref etc. are
   419 replaced by functions simpset:unit->simpset and
   420 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   421 to patch your ML files accordingly;
   422 
   423 * HTML output now includes theory graph data for display with Java
   424 applet or isatool browser; data generated automatically via isatool
   425 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   426 
   427 * defs may now be conditional; improved rewrite_goals_tac to handle
   428 conditional equations;
   429 
   430 * defs now admits additional type arguments, using TYPE('a) syntax;
   431 
   432 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   433 creates a new theory node; implicit merge of thms' signatures is
   434 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   435 transfer:theory->thm->thm in (rare) cases;
   436 
   437 * improved handling of draft signatures / theories; draft thms (and
   438 ctyps, cterms) are automatically promoted to real ones;
   439 
   440 * slightly changed interfaces for oracles: admit many per theory, named
   441 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   442 
   443 * print_goals: optional output of const types (set show_consts and
   444 show_types);
   445 
   446 * improved output of warnings (###) and errors (***);
   447 
   448 * subgoal_tac displays a warning if the new subgoal has type variables;
   449 
   450 * removed old README and Makefiles;
   451 
   452 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   453 
   454 * removed obsolete init_pps and init_database;
   455 
   456 * deleted the obsolete tactical STATE, which was declared by
   457     fun STATE tacfun st = tacfun st st;
   458 
   459 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   460 (which abbreviates $HOME);
   461 
   462 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   463 use isatool fixseq to adapt your ML programs (this works for fully
   464 qualified references to the Sequence structure only!);
   465 
   466 * use_thy no longer requires writable current directory; it always
   467 reloads .ML *and* .thy file, if either one is out of date;
   468 
   469 
   470 *** Classical Reasoner ***
   471 
   472 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   473 tactics that use classical reasoning to simplify a subgoal without
   474 splitting it into several subgoals;
   475 
   476 * Safe_tac: like safe_tac but uses the default claset;
   477 
   478 
   479 *** Simplifier ***
   480 
   481 * added simplification meta rules:
   482     (asm_)(full_)simplify: simpset -> thm -> thm;
   483 
   484 * simplifier.ML no longer part of Pure -- has to be loaded by object
   485 logics (again);
   486 
   487 * added prems argument to simplification procedures;
   488 
   489 * HOL, FOL, ZF: added infix function `addsplits':
   490   instead of `<simpset> setloop (split_tac <thms>)'
   491   you can simply write `<simpset> addsplits <thms>'
   492 
   493 
   494 *** Syntax ***
   495 
   496 * TYPE('a) syntax for type reflection terms;
   497 
   498 * no longer handles consts with name "" -- declare as 'syntax' instead;
   499 
   500 * pretty printer: changed order of mixfix annotation preference (again!);
   501 
   502 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   503 
   504 
   505 *** HOL ***
   506 
   507 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   508   with `addloop' of the simplifier to faciliate case splitting in premises.
   509 
   510 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   511 
   512 * HOL/Auth: new protocol proofs including some for the Internet
   513   protocol TLS;
   514 
   515 * HOL/Map: new theory of `maps' a la VDM;
   516 
   517 * HOL/simplifier: simplification procedures nat_cancel_sums for
   518 cancelling out common nat summands from =, <, <= (in)equalities, or
   519 differences; simplification procedures nat_cancel_factor for
   520 cancelling common factor from =, <, <= (in)equalities over natural
   521 sums; nat_cancel contains both kinds of procedures, it is installed by
   522 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   523 
   524 * HOL/simplifier: terms of the form
   525   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   526   are rewritten to
   527   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   528   and those of the form
   529   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   530   are rewritten to
   531   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   532 
   533 * HOL/datatype
   534   Each datatype `t' now comes with a theorem `split_t_case' of the form
   535 
   536   P(t_case f1 ... fn x) =
   537      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   538         ...
   539        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   540      )
   541 
   542   and a theorem `split_t_case_asm' of the form
   543 
   544   P(t_case f1 ... fn x) =
   545     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   546         ...
   547        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   548      )
   549   which can be added to a simpset via `addsplits'. The existing theorems
   550   expand_list_case and expand_option_case have been renamed to
   551   split_list_case and split_option_case.
   552 
   553 * HOL/Arithmetic:
   554   - `pred n' is automatically converted to `n-1'.
   555     Users are strongly encouraged not to use `pred' any longer,
   556     because it will disappear altogether at some point.
   557   - Users are strongly encouraged to write "0 < n" rather than
   558     "n ~= 0". Theorems and proof tools have been modified towards this
   559     `standard'.
   560 
   561 * HOL/Lists:
   562   the function "set_of_list" has been renamed "set" (and its theorems too);
   563   the function "nth" now takes its arguments in the reverse order and
   564   has acquired the infix notation "!" as in "xs!n".
   565 
   566 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   567 
   568 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   569   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   570 
   571 * HOL/record: extensible records with schematic structural subtyping
   572 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   573 still lacks various theorems and concrete record syntax;
   574 
   575 
   576 *** HOLCF ***
   577 
   578 * removed "axioms" and "generated by" sections;
   579 
   580 * replaced "ops" section by extended "consts" section, which is capable of
   581   handling the continuous function space "->" directly;
   582 
   583 * domain package:
   584   . proves theorems immediately and stores them in the theory,
   585   . creates hierachical name space,
   586   . now uses normal mixfix annotations (instead of cinfix...),
   587   . minor changes to some names and values (for consistency),
   588   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   589   . separator between mutual domain defs: changed "," to "and",
   590   . improved handling of sort constraints;  now they have to
   591     appear on the left-hand side of the equations only;
   592 
   593 * fixed LAM <x,y,zs>.b syntax;
   594 
   595 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   596 adm (%x. P (t x)), where P is chainfinite and t continuous;
   597 
   598 
   599 *** FOL and ZF ***
   600 
   601 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   602   with `addloop' of the simplifier to faciliate case splitting in premises.
   603 
   604 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   605 in HOL, they strip ALL and --> from proved theorems;
   606 
   607 
   608 
   609 New in Isabelle94-8 (May 1997)
   610 ------------------------------
   611 
   612 *** General Changes ***
   613 
   614 * new utilities to build / run / maintain Isabelle etc. (in parts
   615 still somewhat experimental); old Makefiles etc. still functional;
   616 
   617 * new 'Isabelle System Manual';
   618 
   619 * INSTALL text, together with ./configure and ./build scripts;
   620 
   621 * reimplemented type inference for greater efficiency, better error
   622 messages and clean internal interface;
   623 
   624 * prlim command for dealing with lots of subgoals (an easier way of
   625 setting goals_limit);
   626 
   627 
   628 *** Syntax ***
   629 
   630 * supports alternative (named) syntax tables (parser and pretty
   631 printer); internal interface is provided by add_modesyntax(_i);
   632 
   633 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   634 be used in conjunction with the Isabelle symbol font; uses the
   635 "symbols" syntax table;
   636 
   637 * added token_translation interface (may translate name tokens in
   638 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   639 the current print_mode); IMPORTANT: user print translation functions
   640 are responsible for marking newly introduced bounds
   641 (Syntax.mark_boundT);
   642 
   643 * token translations for modes "xterm" and "xterm_color" that display
   644 names in bold, underline etc. or colors (which requires a color
   645 version of xterm);
   646 
   647 * infixes may now be declared with names independent of their syntax;
   648 
   649 * added typed_print_translation (like print_translation, but may
   650 access type of constant);
   651 
   652 
   653 *** Classical Reasoner ***
   654 
   655 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   656 some limitations.  Blast_tac...
   657   + ignores addss, addbefore, addafter; this restriction is intrinsic
   658   + ignores elimination rules that don't have the correct format
   659         (the conclusion MUST be a formula variable)
   660   + ignores types, which can make HOL proofs fail
   661   + rules must not require higher-order unification, e.g. apply_type in ZF
   662     [message "Function Var's argument not a bound variable" relates to this]
   663   + its proof strategy is more general but can actually be slower
   664 
   665 * substitution with equality assumptions no longer permutes other
   666 assumptions;
   667 
   668 * minor changes in semantics of addafter (now called addaltern); renamed
   669 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   670 (and access functions for it);
   671 
   672 * improved combination of classical reasoner and simplifier:
   673   + functions for handling clasimpsets
   674   + improvement of addss: now the simplifier is called _after_ the
   675     safe steps.
   676   + safe variant of addss called addSss: uses safe simplifications
   677     _during_ the safe steps. It is more complete as it allows multiple
   678     instantiations of unknowns (e.g. with slow_tac).
   679 
   680 *** Simplifier ***
   681 
   682 * added interface for simplification procedures (functions that
   683 produce *proven* rewrite rules on the fly, depending on current
   684 redex);
   685 
   686 * ordering on terms as parameter (used for ordered rewriting);
   687 
   688 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   689 
   690 * the solver is now split into a safe and an unsafe part.
   691 This should be invisible for the normal user, except that the
   692 functions setsolver and addsolver have been renamed to setSolver and
   693 addSolver; added safe_asm_full_simp_tac;
   694 
   695 
   696 *** HOL ***
   697 
   698 * a generic induction tactic `induct_tac' which works for all datatypes and
   699 also for type `nat';
   700 
   701 * a generic case distinction tactic `exhaust_tac' which works for all
   702 datatypes and also for type `nat';
   703 
   704 * each datatype comes with a function `size';
   705 
   706 * patterns in case expressions allow tuple patterns as arguments to
   707 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   708 
   709 * primrec now also works with type nat;
   710 
   711 * recdef: a new declaration form, allows general recursive functions to be
   712 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   713 
   714 * the constant for negation has been renamed from "not" to "Not" to
   715 harmonize with FOL, ZF, LK, etc.;
   716 
   717 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   718 infinite lists;
   719 
   720 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   721 
   722 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   723 problems in commutative rings, using axiomatic type classes for + and *;
   724 
   725 * more examples in HOL/MiniML and HOL/Auth;
   726 
   727 * more default rewrite rules for quantifiers, union/intersection;
   728 
   729 * a new constant `arbitrary == @x.False';
   730 
   731 * HOLCF/IOA replaces old HOL/IOA;
   732 
   733 * HOLCF changes: derived all rules and arities
   734   + axiomatic type classes instead of classes
   735   + typedef instead of faking type definitions
   736   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   737   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   738   + eliminated the types void, one, tr
   739   + use unit lift and bool lift (with translations) instead of one and tr
   740   + eliminated blift from Lift3.thy (use Def instead of blift)
   741   all eliminated rules are derived as theorems --> no visible changes ;
   742 
   743 
   744 *** ZF ***
   745 
   746 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   747 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   748 as ZF_cs addSIs [equalityI];
   749 
   750 
   751 
   752 New in Isabelle94-7 (November 96)
   753 ---------------------------------
   754 
   755 * allowing negative levels (as offsets) in prlev and choplev;
   756 
   757 * super-linear speedup for large simplifications;
   758 
   759 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   760 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   761 FAIL); can suppress it using the command Delsimps (ex_simps @
   762 all_simps); De Morgan laws are also now included, by default;
   763 
   764 * improved printing of ==>  :  ~:
   765 
   766 * new object-logic "Sequents" adds linear logic, while replacing LK
   767 and Modal (thanks to Sara Kalvala);
   768 
   769 * HOL/Auth: correctness proofs for authentication protocols;
   770 
   771 * HOL: new auto_tac combines rewriting and classical reasoning (many
   772 examples on HOL/Auth);
   773 
   774 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   775 the rewriter and classical reasoner simultaneously;
   776 
   777 * function uresult no longer returns theorems in "standard" format;
   778 regain previous version by: val uresult = standard o uresult;
   779 
   780 
   781 
   782 New in Isabelle94-6
   783 -------------------
   784 
   785 * oracles -- these establish an interface between Isabelle and trusted
   786 external reasoners, which may deliver results as theorems;
   787 
   788 * proof objects (in particular record all uses of oracles);
   789 
   790 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   791 
   792 * "constdefs" section in theory files;
   793 
   794 * "primrec" section (HOL) no longer requires names;
   795 
   796 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   797 
   798 
   799 
   800 New in Isabelle94-5
   801 -------------------
   802 
   803 * reduced space requirements;
   804 
   805 * automatic HTML generation from theories;
   806 
   807 * theory files no longer require "..." (quotes) around most types;
   808 
   809 * new examples, including two proofs of the Church-Rosser theorem;
   810 
   811 * non-curried (1994) version of HOL is no longer distributed;
   812 
   813 
   814 
   815 New in Isabelle94-4
   816 -------------------
   817 
   818 * greatly reduced space requirements;
   819 
   820 * theory files (.thy) no longer require \...\ escapes at line breaks;
   821 
   822 * searchable theorem database (see the section "Retrieving theorems" on
   823 page 8 of the Reference Manual);
   824 
   825 * new examples, including Grabczewski's monumental case study of the
   826 Axiom of Choice;
   827 
   828 * The previous version of HOL renamed to Old_HOL;
   829 
   830 * The new version of HOL (previously called CHOL) uses a curried syntax
   831 for functions.  Application looks like f a b instead of f(a,b);
   832 
   833 * Mutually recursive inductive definitions finally work in HOL;
   834 
   835 * In ZF, pattern-matching on tuples is now available in all abstractions and
   836 translates to the operator "split";
   837 
   838 
   839 
   840 New in Isabelle94-3
   841 -------------------
   842 
   843 * new infix operator, addss, allowing the classical reasoner to
   844 perform simplification at each step of its search.  Example:
   845         fast_tac (cs addss ss)
   846 
   847 * a new logic, CHOL, the same as HOL, but with a curried syntax
   848 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
   849 look like (a,b) instead of <a,b>;
   850 
   851 * PLEASE NOTE: CHOL will eventually replace HOL!
   852 
   853 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   854 It translates to the operator "split".  A new theory of integers is available;
   855 
   856 * In ZF, integer numerals now denote two's-complement binary integers.
   857 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   858 
   859 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
   860 of the Axiom of Choice;
   861 
   862 
   863 
   864 New in Isabelle94-2
   865 -------------------
   866 
   867 * Significantly faster resolution;
   868 
   869 * the different sections in a .thy file can now be mixed and repeated
   870 freely;
   871 
   872 * Database of theorems for FOL, HOL and ZF.  New
   873 commands including qed, qed_goal and bind_thm store theorems in the database.
   874 
   875 * Simple database queries: return a named theorem (get_thm) or all theorems of
   876 a given theory (thms_of), or find out what theory a theorem was proved in
   877 (theory_of_thm);
   878 
   879 * Bugs fixed in the inductive definition and datatype packages;
   880 
   881 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   882 and HOL_dup_cs obsolete;
   883 
   884 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   885 have been removed;
   886 
   887 * Simpler definition of function space in ZF;
   888 
   889 * new results about cardinal and ordinal arithmetic in ZF;
   890 
   891 * 'subtype' facility in HOL for introducing new types as subsets of existing
   892 types;
   893 
   894 
   895 $Id$