NEWS
author wenzelm
Fri Sep 03 14:23:15 1999 +0200 (1999-09-03)
changeset 7450 e329ca03fd00
parent 7444 ee17ad649c26
child 7492 44b333fb5b80
permissions -rw-r--r--
added bind_thms;
     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: The THEN and ELSE parts of conditional expressions (if P then x else y)
    11 are no longer simplified.  (This allows the simplifier to unfold recursive
    12 functional programs.)  To restore the old behaviour, declare
    13 
    14     Delcongs [if_weak_cong];
    15 
    16 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    17 complement;
    18 
    19 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    20 
    21 * HOL/typedef: fixed type inference for representing set; type
    22 arguments now have to occur explicitly on the rhs as type constraints;
    23 
    24 * ZF: The con_defs part of an inductive definition may no longer refer
    25 to constants declared in the same theory;
    26 
    27 * HOL, ZF: the function mk_cases, generated by the inductive
    28 definition package, has lost an argument.  To simplify its result, it
    29 uses the default simpset instead of a supplied list of theorems.
    30 
    31 * HOL/List: the constructors of type list are now Nil and Cons;
    32 
    33 
    34 *** Proof tools ***
    35 
    36 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
    37 decision procedure for linear arithmetic. Currently it is used for
    38 types `nat' and `int' in HOL (see below) but can, should and will be
    39 instantiated for other types and logics as well.
    40 
    41 * The simplifier now accepts rewrite rules with flexible heads, eg
    42      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
    43   They are applied like any rule with a non-pattern lhs, i.e. by first-order
    44   matching.
    45 
    46 *** General ***
    47 
    48 * new Isabelle/Isar subsystem provides an alternative to traditional
    49 tactical theorem proving; together with the ProofGeneral/isar user
    50 interface it offers an interactive environment for developing human
    51 readable proof documents (Isar == Intelligible semi-automated
    52 reasoning); see isatool doc isar-ref and
    53 http://isabelle.in.tum.de/Isar/ for more information;
    54 
    55 * native support for Proof General, both for classic Isabelle and
    56 Isabelle/Isar (the latter is slightly better supported and more
    57 robust);
    58 
    59 * Isabelle manuals now also available as PDF;
    60 
    61 * improved browser info generation: better HTML markup (including
    62 colors), graph views in several sizes; isatool usedir now provides a
    63 proper interface for user theories (via -P option);
    64 
    65 * theory loader rewritten from scratch (may not be fully
    66 bug-compatible); old loadpath variable has been replaced by show_path,
    67 add_path, del_path, reset_path functions; new operations such as
    68 update_thy, touch_thy, remove_thy (see also isatool doc ref);
    69 
    70 * improved isatool install: option -k creates KDE application icon,
    71 option -p DIR installs standalone binaries;
    72 
    73 * added ML_PLATFORM setting (useful for cross-platform installations);
    74 more robust handling of platform specific ML images for SML/NJ;
    75 
    76 * path element specification '~~' refers to '$ISABELLE_HOME';
    77 
    78 * in locales, the "assumes" and "defines" parts may be omitted if
    79 empty;
    80 
    81 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
    82 long arrows);
    83 
    84 * new print_mode "HTML";
    85 
    86 * new flag show_tags controls display of tags of theorems (which are
    87 basically just comments that may be attached by some tools);
    88 
    89 * Isamode 2.6 requires patch to accomodate change of Isabelle font
    90 mode and goal output format:
    91 
    92 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
    93 244c244
    94 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
    95 ---
    96 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
    97 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
    98 181c181
    99 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   100 ---
   101 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   102 
   103 * function bind_thms stores lists of theorems (cf. bind_thm);
   104 
   105 
   106 *** HOL ***
   107 
   108 ** HOL arithmetic **
   109 
   110 * There are now decision procedures for linear arithmetic over nat and
   111 int:
   112 
   113 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   114 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   115 are treated as atomic; subformulae not involving type `nat' or `int'
   116 are ignored; quantified subformulae are ignored unless they are
   117 positive universal or negative existential. The tactic has to be
   118 invoked by hand and can be a little bit slow. In particular, the
   119 running time is exponential in the number of occurrences of `min' and
   120 `max', and `-' on `nat'.
   121 
   122 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   123 (negated) (in)equalities among the premises and the conclusion into
   124 account (i.e. no compound formulae) and does not know about `min' and
   125 `max', and `-' on `nat'. It is fast and is used automatically by the
   126 simplifier.
   127 
   128 NB: At the moment, these decision procedures do not cope with mixed
   129 nat/int formulae where the two parts interact, such as `m < n ==>
   130 int(m) < int(n)'.
   131 
   132 * HOL/Numeral provides a generic theory of numerals (encoded
   133 efficiently as bit strings); setup for types nat/int/real is in place;
   134 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   135 int, existing theories and proof scripts may require a few additional
   136 type constraints;
   137 
   138 * integer division and remainder can now be performed on constant
   139 arguments;
   140 
   141 * many properties of integer multiplication, division and remainder
   142 are now available;
   143 
   144 * An interface to the Stanford Validity Checker (SVC) is available through the
   145 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   146 are proved automatically.  SVC must be installed separately, and its results
   147 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   148 invocation of the underlying oracle).  For SVC see
   149   http://verify.stanford.edu/SVC
   150 
   151 * IsaMakefile: the HOL-Real target now builds an actual image;
   152 
   153 
   154 ** HOL misc **
   155 
   156 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   157 -- avoids syntactic ambiguities and treats state, transition, and
   158 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   159 changed syntax and (many) tactics;
   160 
   161 * HOL/datatype: Now also handles arbitrarily branching datatypes
   162   (using function types) such as
   163 
   164   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   165 
   166 * HOL/record: record_simproc (part of the default simpset) takes care
   167 of selectors applied to updated records; record_split_tac is no longer
   168 part of the default claset; update_defs may now be removed from the
   169 simpset in many cases; COMPATIBILITY: old behavior achieved by
   170 
   171   claset_ref () := claset() addSWrapper record_split_wrapper;
   172   Delsimprocs [record_simproc]
   173 
   174 * HOL/typedef: fixed type inference for representing set; type
   175 arguments now have to occur explicitly on the rhs as type constraints;
   176 
   177 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   178 names rather than an ML expression;
   179 
   180 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   181 supplied later.  Program schemes can be defined, such as
   182     "While B C s = (if B s then While B C (C s) else s)"
   183 where the well-founded relation can be chosen after B and C have been given.
   184 
   185 * HOL/List: the constructors of type list are now Nil and Cons;
   186 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   187 course, ML tools referring to List.list.op # etc. have to be adapted;
   188 
   189 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   190 disabled by default; run isabelle with option -m HOL to get back to
   191 the original Gordon/HOL-style output;
   192 
   193 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   194 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   195 
   196 * HOL basic syntax simplified (more orthogonal): all variants of
   197 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   198 Eps operator is provided as well: "SOME x. P[x]";
   199 
   200 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   201 
   202 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   203 thus available for user theories;
   204 
   205 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   206 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   207 time;
   208 
   209 
   210 *** LK ***
   211 
   212 * the notation <<...>> is now available as a notation for sequences of
   213 formulas;
   214 
   215 * the simplifier is now installed
   216 
   217 * the axiom system has been generalized (thanks to Soren Heilmann) 
   218 
   219 * the classical reasoner now has a default rule database
   220 
   221 
   222 *** ZF ***
   223 
   224 * new primrec section allows primitive recursive functions to be given
   225 directly (as in HOL) over datatypes and the natural numbers;
   226 
   227 * new tactics induct_tac and exhaust_tac for induction (or case
   228 analysis) over datatypes and the natural numbers;
   229 
   230 * the datatype declaration of type T now defines the recursor T_rec;
   231 
   232 * simplification automatically does freeness reasoning for datatype
   233 constructors;
   234 
   235 * automatic type-inference, with AddTCs command to insert new
   236 type-checking rules;
   237 
   238 * datatype introduction rules are now added as Safe Introduction rules
   239 to the claset;
   240 
   241 * the syntax "if P then x else y" is now available in addition to
   242 if(P,x,y);
   243 
   244 
   245 *** Internal programming interfaces ***
   246 
   247 * structures Vartab / Termtab (instances of TableFun) offer efficient
   248 tables indexed by indexname_ord / term_ord (compatible with aconv);
   249 
   250 * AxClass.axclass_tac lost the theory argument;
   251 
   252 * tuned current_goals_markers semantics: begin / end goal avoids
   253 printing empty lines;
   254 
   255 * removed prs and prs_fn hook, which was broken because it did not
   256 include \n in its semantics, forcing writeln to add one
   257 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   258 string -> unit if you really want to output text without newline;
   259 
   260 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   261 plain output, interface builders may have to enable 'isabelle_font'
   262 mode to get Isabelle font glyphs as before;
   263 
   264 * refined token_translation interface; INCOMPATIBILITY: output length
   265 now of type real instead of int;
   266 
   267 * theory loader actions may be traced via new ThyInfo.add_hook
   268 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   269 your own database of information attached to *whole* theories -- as
   270 opposed to intra-theory data slots offered via TheoryDataFun;
   271 
   272 
   273 
   274 New in Isabelle98-1 (October 1998)
   275 ----------------------------------
   276 
   277 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   278 
   279 * several changes of automated proof tools;
   280 
   281 * HOL: major changes to the inductive and datatype packages, including
   282 some minor incompatibilities of theory syntax;
   283 
   284 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   285 called `inj_on';
   286 
   287 * HOL: removed duplicate thms in Arith:
   288   less_imp_add_less  should be replaced by  trans_less_add1
   289   le_imp_add_le      should be replaced by  trans_le_add1
   290 
   291 * HOL: unary minus is now overloaded (new type constraints may be
   292 required);
   293 
   294 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   295 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   296 now taken as an integer constant.
   297 
   298 * Pure: ML function 'theory_of' renamed to 'theory';
   299 
   300 
   301 *** Proof tools ***
   302 
   303 * Simplifier:
   304   1. Asm_full_simp_tac is now more aggressive.
   305      1. It will sometimes reorient premises if that increases their power to
   306         simplify.
   307      2. It does no longer proceed strictly from left to right but may also
   308         rotate premises to achieve further simplification.
   309      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   310      old Asm_full_simp_tac in that it does not rotate premises.
   311   2. The simplifier now knows a little bit about nat-arithmetic.
   312 
   313 * Classical reasoner: wrapper mechanism for the classical reasoner now
   314 allows for selected deletion of wrappers, by introduction of names for
   315 wrapper functionals.  This implies that addbefore, addSbefore,
   316 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   317 and that adding two tactics with the same name overwrites the first
   318 one (emitting a warning).
   319   type wrapper = (int -> tactic) -> (int -> tactic)
   320   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   321   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   322   delWrapper, delSWrapper: claset *  string            -> claset
   323   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   324 
   325 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   326 semantics; addbefore now affects only the unsafe part of step_tac
   327 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   328 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   329 by Force_tac;
   330 
   331 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   332 compWrapper; added safe wrapper (and access functions for it);
   333 
   334 * HOL/split_all_tac is now much faster and fails if there is nothing
   335 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   336 and the names of the automatically generated variables have changed.
   337 split_all_tac has moved within claset() from unsafe wrappers to safe
   338 wrappers, which means that !!-bound variables are split much more
   339 aggressively, and safe_tac and clarify_tac now split such variables.
   340 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   341 Note: the same holds for record_split_tac, which does the job of
   342 split_all_tac for record fields.
   343 
   344 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   345 permanently to the default simpset using Addsplits just like
   346 Addsimps. They can be removed via Delsplits just like
   347 Delsimps. Lower-case versions are also available.
   348 
   349 * HOL/Simplifier: The rule split_if is now part of the default
   350 simpset. This means that the simplifier will eliminate all occurrences
   351 of if-then-else in the conclusion of a goal. To prevent this, you can
   352 either remove split_if completely from the default simpset by
   353 `Delsplits [split_if]' or remove it in a specific call of the
   354 simplifier using `... delsplits [split_if]'.  You can also add/delete
   355 other case splitting rules to/from the default simpset: every datatype
   356 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   357 t is the name of the datatype).
   358 
   359 * Classical reasoner / Simplifier combination: new force_tac (and
   360 derivatives Force_tac, force) combines rewriting and classical
   361 reasoning (and whatever other tools) similarly to auto_tac, but is
   362 aimed to solve the given subgoal completely.
   363 
   364 
   365 *** General ***
   366 
   367 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   368 and `goalw': the theory is no longer needed as an explicit argument -
   369 the current theory context is used; assumptions are no longer returned
   370 at the ML-level unless one of them starts with ==> or !!; it is
   371 recommended to convert to these new commands using isatool fixgoal
   372 (backup your sources first!);
   373 
   374 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   375 the current theory context, and 'theory' to lookup stored theories;
   376 
   377 * new theory section 'locale' for declaring constants, assumptions and
   378 definitions that have local scope;
   379 
   380 * new theory section 'nonterminals' for purely syntactic types;
   381 
   382 * new theory section 'setup' for generic ML setup functions
   383 (e.g. package initialization);
   384 
   385 * the distribution now includes Isabelle icons: see
   386 lib/logo/isabelle-{small,tiny}.xpm;
   387 
   388 * isatool install - install binaries with absolute references to
   389 ISABELLE_HOME/bin;
   390 
   391 * isatool logo -- create instances of the Isabelle logo (as EPS);
   392 
   393 * print mode 'emacs' reserved for Isamode;
   394 
   395 * support multiple print (ast) translations per constant name;
   396 
   397 * theorems involving oracles are now printed with a suffixed [!];
   398 
   399 
   400 *** HOL ***
   401 
   402 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   403 
   404 * HOL/inductive package reorganized and improved: now supports mutual
   405 definitions such as
   406 
   407   inductive EVEN ODD
   408     intrs
   409       null "0 : EVEN"
   410       oddI "n : EVEN ==> Suc n : ODD"
   411       evenI "n : ODD ==> Suc n : EVEN"
   412 
   413 new theorem list "elims" contains an elimination rule for each of the
   414 recursive sets; inductive definitions now handle disjunctive premises
   415 correctly (also ZF);
   416 
   417 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   418 "mutual_induct" no longer exists - the induction rule is always
   419 contained in "induct";
   420 
   421 
   422 * HOL/datatype package re-implemented and greatly improved: now
   423 supports mutually recursive datatypes such as
   424 
   425   datatype
   426     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   427             | SUM ('a aexp) ('a aexp)
   428             | DIFF ('a aexp) ('a aexp)
   429             | NUM 'a
   430   and
   431     'a bexp = LESS ('a aexp) ('a aexp)
   432             | AND ('a bexp) ('a bexp)
   433             | OR ('a bexp) ('a bexp)
   434 
   435 as well as indirectly recursive datatypes such as
   436 
   437   datatype
   438     ('a, 'b) term = Var 'a
   439                   | App 'b ((('a, 'b) term) list)
   440 
   441 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   442 induction on mutually / indirectly recursive datatypes.
   443 
   444 Primrec equations are now stored in theory and can be accessed via
   445 <function_name>.simps.
   446 
   447 INCOMPATIBILITIES:
   448 
   449   - Theories using datatypes must now have theory Datatype as an
   450     ancestor.
   451   - The specific <typename>.induct_tac no longer exists - use the
   452     generic induct_tac instead.
   453   - natE has been renamed to nat.exhaust - use exhaust_tac
   454     instead of res_inst_tac ... natE. Note that the variable
   455     names in nat.exhaust differ from the names in natE, this
   456     may cause some "fragile" proofs to fail.
   457   - The theorems split_<typename>_case and split_<typename>_case_asm
   458     have been renamed to <typename>.split and <typename>.split_asm.
   459   - Since default sorts of type variables are now handled correctly,
   460     some datatype definitions may have to be annotated with explicit
   461     sort constraints.
   462   - Primrec definitions no longer require function name and type
   463     of recursive argument.
   464 
   465 Consider using isatool fixdatatype to adapt your theories and proof
   466 scripts to the new package (backup your sources first!).
   467 
   468 
   469 * HOL/record package: considerably improved implementation; now
   470 includes concrete syntax for record types, terms, updates; theorems
   471 for surjective pairing and splitting !!-bound record variables; proof
   472 support is as follows:
   473 
   474   1) standard conversions (selectors or updates applied to record
   475 constructor terms) are part of the standard simpset;
   476 
   477   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   478 made part of standard simpset and claset via addIffs;
   479 
   480   3) a tactic for record field splitting (record_split_tac) is part of
   481 the standard claset (addSWrapper);
   482 
   483 To get a better idea about these rules you may retrieve them via
   484 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   485 the name of your record type.
   486 
   487 The split tactic 3) conceptually simplifies by the following rule:
   488 
   489   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   490 
   491 Thus any record variable that is bound by meta-all will automatically
   492 blow up into some record constructor term, consequently the
   493 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   494 solve record problems automatically.
   495 
   496 
   497 * reorganized the main HOL image: HOL/Integ and String loaded by
   498 default; theory Main includes everything;
   499 
   500 * automatic simplification of integer sums and comparisons, using cancellation;
   501 
   502 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   503 
   504 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   505 
   506 * many new identities for unions, intersections, set difference, etc.;
   507 
   508 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   509 called split_if, split_split, split_sum_case and split_nat_case (to go
   510 with add/delsplits);
   511 
   512 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   513 (?x::unit) = (); this is made part of the default simpset, which COULD
   514 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   515 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   516 unit_abs_eta_conv is added in order to counter the effect of
   517 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   518 %u.f();
   519 
   520 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   521 makes more sense);
   522 
   523 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   524   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   525   disjointness reasoning but breaking a few old proofs.
   526 
   527 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   528 to 'converse' from 'inverse' (for compatibility with ZF and some
   529 literature);
   530 
   531 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   532 the well-founded relation;
   533 
   534 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   535     Compl A.  The "Compl" syntax remains available as input syntax for this
   536     release ONLY.
   537 
   538 * HOL/Update: new theory of function updates:
   539     f(a:=b) == %x. if x=a then b else f x
   540 may also be iterated as in f(a:=b,c:=d,...);
   541 
   542 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   543 
   544 * HOL/List:
   545   - new function list_update written xs[i:=v] that updates the i-th
   546     list position. May also be iterated as in xs[i:=a,j:=b,...].
   547   - new function `upt' written [i..j(] which generates the list
   548     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   549     bound write [i..j], which is a shorthand for [i..j+1(].
   550   - new lexicographic orderings and corresponding wellfoundedness theorems.
   551 
   552 * HOL/Arith:
   553   - removed 'pred' (predecessor) function;
   554   - generalized some theorems about n-1;
   555   - many new laws about "div" and "mod";
   556   - new laws about greatest common divisors (see theory ex/Primes);
   557 
   558 * HOL/Relation: renamed the relational operator r^-1 "converse"
   559 instead of "inverse";
   560 
   561 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   562   of the multiset ordering;
   563 
   564 * directory HOL/Real: a construction of the reals using Dedekind cuts
   565   (not included by default);
   566 
   567 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   568 
   569 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   570   programs, i.e. different program variables may have different types.
   571 
   572 * calling (stac rew i) now fails if "rew" has no effect on the goal
   573   [previously, this check worked only if the rewrite rule was unconditional]
   574   Now rew can involve either definitions or equalities (either == or =).
   575 
   576 
   577 *** ZF ***
   578 
   579 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   580   only the theorems proved on ZF.ML;
   581 
   582 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   583   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   584   disjointness reasoning but breaking a few old proofs.
   585 
   586 * ZF/Update: new theory of function updates
   587     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   588   may also be iterated as in f(a:=b,c:=d,...);
   589 
   590 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   591 
   592 * calling (stac rew i) now fails if "rew" has no effect on the goal
   593   [previously, this check worked only if the rewrite rule was unconditional]
   594   Now rew can involve either definitions or equalities (either == or =).
   595 
   596 * case_tac provided for compatibility with HOL
   597     (like the old excluded_middle_tac, but with subgoals swapped)
   598 
   599 
   600 *** Internal programming interfaces ***
   601 
   602 * Pure: several new basic modules made available for general use, see
   603 also src/Pure/README;
   604 
   605 * improved the theory data mechanism to support encapsulation (data
   606 kind name replaced by private Object.kind, acting as authorization
   607 key); new type-safe user interface via functor TheoryDataFun; generic
   608 print_data function becomes basically useless;
   609 
   610 * removed global_names compatibility flag -- all theory declarations
   611 are qualified by default;
   612 
   613 * module Pure/Syntax now offers quote / antiquote translation
   614 functions (useful for Hoare logic etc. with implicit dependencies);
   615 see HOL/ex/Antiquote for an example use;
   616 
   617 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   618 cterm -> thm;
   619 
   620 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   621 subgoal;
   622 
   623 * Display.print_goals function moved to Locale.print_goals;
   624 
   625 * standard print function for goals supports current_goals_markers
   626 variable for marking begin of proof, end of proof, start of goal; the
   627 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   628 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   629 for example;
   630 
   631 
   632 
   633 New in Isabelle98 (January 1998)
   634 --------------------------------
   635 
   636 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   637 
   638 * changed lexical syntax of terms / types: dots made part of long
   639 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   640 
   641 * simpset (and claset) reference variable replaced by functions
   642 simpset / simpset_ref;
   643 
   644 * no longer supports theory aliases (via merge) and non-trivial
   645 implicit merge of thms' signatures;
   646 
   647 * most internal names of constants changed due to qualified names;
   648 
   649 * changed Pure/Sequence interface (see Pure/seq.ML);
   650 
   651 
   652 *** General Changes ***
   653 
   654 * hierachically structured name spaces (for consts, types, axms, thms
   655 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   656 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   657 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   658 long_names for fully qualified output names; NOTE: ML programs
   659 (special tactics, packages etc.) referring to internal names may have
   660 to be adapted to cope with fully qualified names; in case of severe
   661 backward campatibility problems try setting 'global_names' at compile
   662 time to have enrything declared within a flat name space; one may also
   663 fine tune name declarations in theories via the 'global' and 'local'
   664 section;
   665 
   666 * reimplemented the implicit simpset and claset using the new anytype
   667 data filed in signatures; references simpset:simpset ref etc. are
   668 replaced by functions simpset:unit->simpset and
   669 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   670 to patch your ML files accordingly;
   671 
   672 * HTML output now includes theory graph data for display with Java
   673 applet or isatool browser; data generated automatically via isatool
   674 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   675 
   676 * defs may now be conditional; improved rewrite_goals_tac to handle
   677 conditional equations;
   678 
   679 * defs now admits additional type arguments, using TYPE('a) syntax;
   680 
   681 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   682 creates a new theory node; implicit merge of thms' signatures is
   683 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   684 transfer:theory->thm->thm in (rare) cases;
   685 
   686 * improved handling of draft signatures / theories; draft thms (and
   687 ctyps, cterms) are automatically promoted to real ones;
   688 
   689 * slightly changed interfaces for oracles: admit many per theory, named
   690 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   691 
   692 * print_goals: optional output of const types (set show_consts and
   693 show_types);
   694 
   695 * improved output of warnings (###) and errors (***);
   696 
   697 * subgoal_tac displays a warning if the new subgoal has type variables;
   698 
   699 * removed old README and Makefiles;
   700 
   701 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   702 
   703 * removed obsolete init_pps and init_database;
   704 
   705 * deleted the obsolete tactical STATE, which was declared by
   706     fun STATE tacfun st = tacfun st st;
   707 
   708 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   709 (which abbreviates $HOME);
   710 
   711 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   712 use isatool fixseq to adapt your ML programs (this works for fully
   713 qualified references to the Sequence structure only!);
   714 
   715 * use_thy no longer requires writable current directory; it always
   716 reloads .ML *and* .thy file, if either one is out of date;
   717 
   718 
   719 *** Classical Reasoner ***
   720 
   721 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   722 tactics that use classical reasoning to simplify a subgoal without
   723 splitting it into several subgoals;
   724 
   725 * Safe_tac: like safe_tac but uses the default claset;
   726 
   727 
   728 *** Simplifier ***
   729 
   730 * added simplification meta rules:
   731     (asm_)(full_)simplify: simpset -> thm -> thm;
   732 
   733 * simplifier.ML no longer part of Pure -- has to be loaded by object
   734 logics (again);
   735 
   736 * added prems argument to simplification procedures;
   737 
   738 * HOL, FOL, ZF: added infix function `addsplits':
   739   instead of `<simpset> setloop (split_tac <thms>)'
   740   you can simply write `<simpset> addsplits <thms>'
   741 
   742 
   743 *** Syntax ***
   744 
   745 * TYPE('a) syntax for type reflection terms;
   746 
   747 * no longer handles consts with name "" -- declare as 'syntax' instead;
   748 
   749 * pretty printer: changed order of mixfix annotation preference (again!);
   750 
   751 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   752 
   753 
   754 *** HOL ***
   755 
   756 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   757   with `addloop' of the simplifier to faciliate case splitting in premises.
   758 
   759 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   760 
   761 * HOL/Auth: new protocol proofs including some for the Internet
   762   protocol TLS;
   763 
   764 * HOL/Map: new theory of `maps' a la VDM;
   765 
   766 * HOL/simplifier: simplification procedures nat_cancel_sums for
   767 cancelling out common nat summands from =, <, <= (in)equalities, or
   768 differences; simplification procedures nat_cancel_factor for
   769 cancelling common factor from =, <, <= (in)equalities over natural
   770 sums; nat_cancel contains both kinds of procedures, it is installed by
   771 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   772 
   773 * HOL/simplifier: terms of the form
   774   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   775   are rewritten to
   776   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   777   and those of the form
   778   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   779   are rewritten to
   780   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   781 
   782 * HOL/datatype
   783   Each datatype `t' now comes with a theorem `split_t_case' of the form
   784 
   785   P(t_case f1 ... fn x) =
   786      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   787         ...
   788        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   789      )
   790 
   791   and a theorem `split_t_case_asm' of the form
   792 
   793   P(t_case f1 ... fn x) =
   794     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   795         ...
   796        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   797      )
   798   which can be added to a simpset via `addsplits'. The existing theorems
   799   expand_list_case and expand_option_case have been renamed to
   800   split_list_case and split_option_case.
   801 
   802 * HOL/Arithmetic:
   803   - `pred n' is automatically converted to `n-1'.
   804     Users are strongly encouraged not to use `pred' any longer,
   805     because it will disappear altogether at some point.
   806   - Users are strongly encouraged to write "0 < n" rather than
   807     "n ~= 0". Theorems and proof tools have been modified towards this
   808     `standard'.
   809 
   810 * HOL/Lists:
   811   the function "set_of_list" has been renamed "set" (and its theorems too);
   812   the function "nth" now takes its arguments in the reverse order and
   813   has acquired the infix notation "!" as in "xs!n".
   814 
   815 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   816 
   817 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   818   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   819 
   820 * HOL/record: extensible records with schematic structural subtyping
   821 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   822 still lacks various theorems and concrete record syntax;
   823 
   824 
   825 *** HOLCF ***
   826 
   827 * removed "axioms" and "generated by" sections;
   828 
   829 * replaced "ops" section by extended "consts" section, which is capable of
   830   handling the continuous function space "->" directly;
   831 
   832 * domain package:
   833   . proves theorems immediately and stores them in the theory,
   834   . creates hierachical name space,
   835   . now uses normal mixfix annotations (instead of cinfix...),
   836   . minor changes to some names and values (for consistency),
   837   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   838   . separator between mutual domain defs: changed "," to "and",
   839   . improved handling of sort constraints;  now they have to
   840     appear on the left-hand side of the equations only;
   841 
   842 * fixed LAM <x,y,zs>.b syntax;
   843 
   844 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   845 adm (%x. P (t x)), where P is chainfinite and t continuous;
   846 
   847 
   848 *** FOL and ZF ***
   849 
   850 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   851   with `addloop' of the simplifier to faciliate case splitting in premises.
   852 
   853 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   854 in HOL, they strip ALL and --> from proved theorems;
   855 
   856 
   857 
   858 New in Isabelle94-8 (May 1997)
   859 ------------------------------
   860 
   861 *** General Changes ***
   862 
   863 * new utilities to build / run / maintain Isabelle etc. (in parts
   864 still somewhat experimental); old Makefiles etc. still functional;
   865 
   866 * new 'Isabelle System Manual';
   867 
   868 * INSTALL text, together with ./configure and ./build scripts;
   869 
   870 * reimplemented type inference for greater efficiency, better error
   871 messages and clean internal interface;
   872 
   873 * prlim command for dealing with lots of subgoals (an easier way of
   874 setting goals_limit);
   875 
   876 
   877 *** Syntax ***
   878 
   879 * supports alternative (named) syntax tables (parser and pretty
   880 printer); internal interface is provided by add_modesyntax(_i);
   881 
   882 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   883 be used in conjunction with the Isabelle symbol font; uses the
   884 "symbols" syntax table;
   885 
   886 * added token_translation interface (may translate name tokens in
   887 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   888 the current print_mode); IMPORTANT: user print translation functions
   889 are responsible for marking newly introduced bounds
   890 (Syntax.mark_boundT);
   891 
   892 * token translations for modes "xterm" and "xterm_color" that display
   893 names in bold, underline etc. or colors (which requires a color
   894 version of xterm);
   895 
   896 * infixes may now be declared with names independent of their syntax;
   897 
   898 * added typed_print_translation (like print_translation, but may
   899 access type of constant);
   900 
   901 
   902 *** Classical Reasoner ***
   903 
   904 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   905 some limitations.  Blast_tac...
   906   + ignores addss, addbefore, addafter; this restriction is intrinsic
   907   + ignores elimination rules that don't have the correct format
   908         (the conclusion MUST be a formula variable)
   909   + ignores types, which can make HOL proofs fail
   910   + rules must not require higher-order unification, e.g. apply_type in ZF
   911     [message "Function Var's argument not a bound variable" relates to this]
   912   + its proof strategy is more general but can actually be slower
   913 
   914 * substitution with equality assumptions no longer permutes other
   915 assumptions;
   916 
   917 * minor changes in semantics of addafter (now called addaltern); renamed
   918 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   919 (and access functions for it);
   920 
   921 * improved combination of classical reasoner and simplifier:
   922   + functions for handling clasimpsets
   923   + improvement of addss: now the simplifier is called _after_ the
   924     safe steps.
   925   + safe variant of addss called addSss: uses safe simplifications
   926     _during_ the safe steps. It is more complete as it allows multiple
   927     instantiations of unknowns (e.g. with slow_tac).
   928 
   929 *** Simplifier ***
   930 
   931 * added interface for simplification procedures (functions that
   932 produce *proven* rewrite rules on the fly, depending on current
   933 redex);
   934 
   935 * ordering on terms as parameter (used for ordered rewriting);
   936 
   937 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   938 
   939 * the solver is now split into a safe and an unsafe part.
   940 This should be invisible for the normal user, except that the
   941 functions setsolver and addsolver have been renamed to setSolver and
   942 addSolver; added safe_asm_full_simp_tac;
   943 
   944 
   945 *** HOL ***
   946 
   947 * a generic induction tactic `induct_tac' which works for all datatypes and
   948 also for type `nat';
   949 
   950 * a generic case distinction tactic `exhaust_tac' which works for all
   951 datatypes and also for type `nat';
   952 
   953 * each datatype comes with a function `size';
   954 
   955 * patterns in case expressions allow tuple patterns as arguments to
   956 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   957 
   958 * primrec now also works with type nat;
   959 
   960 * recdef: a new declaration form, allows general recursive functions to be
   961 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   962 
   963 * the constant for negation has been renamed from "not" to "Not" to
   964 harmonize with FOL, ZF, LK, etc.;
   965 
   966 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   967 infinite lists;
   968 
   969 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   970 
   971 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   972 problems in commutative rings, using axiomatic type classes for + and *;
   973 
   974 * more examples in HOL/MiniML and HOL/Auth;
   975 
   976 * more default rewrite rules for quantifiers, union/intersection;
   977 
   978 * a new constant `arbitrary == @x.False';
   979 
   980 * HOLCF/IOA replaces old HOL/IOA;
   981 
   982 * HOLCF changes: derived all rules and arities
   983   + axiomatic type classes instead of classes
   984   + typedef instead of faking type definitions
   985   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   986   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   987   + eliminated the types void, one, tr
   988   + use unit lift and bool lift (with translations) instead of one and tr
   989   + eliminated blift from Lift3.thy (use Def instead of blift)
   990   all eliminated rules are derived as theorems --> no visible changes ;
   991 
   992 
   993 *** ZF ***
   994 
   995 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   996 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   997 as ZF_cs addSIs [equalityI];
   998 
   999 
  1000 
  1001 New in Isabelle94-7 (November 96)
  1002 ---------------------------------
  1003 
  1004 * allowing negative levels (as offsets) in prlev and choplev;
  1005 
  1006 * super-linear speedup for large simplifications;
  1007 
  1008 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1009 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1010 FAIL); can suppress it using the command Delsimps (ex_simps @
  1011 all_simps); De Morgan laws are also now included, by default;
  1012 
  1013 * improved printing of ==>  :  ~:
  1014 
  1015 * new object-logic "Sequents" adds linear logic, while replacing LK
  1016 and Modal (thanks to Sara Kalvala);
  1017 
  1018 * HOL/Auth: correctness proofs for authentication protocols;
  1019 
  1020 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1021 examples on HOL/Auth);
  1022 
  1023 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1024 the rewriter and classical reasoner simultaneously;
  1025 
  1026 * function uresult no longer returns theorems in "standard" format;
  1027 regain previous version by: val uresult = standard o uresult;
  1028 
  1029 
  1030 
  1031 New in Isabelle94-6
  1032 -------------------
  1033 
  1034 * oracles -- these establish an interface between Isabelle and trusted
  1035 external reasoners, which may deliver results as theorems;
  1036 
  1037 * proof objects (in particular record all uses of oracles);
  1038 
  1039 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1040 
  1041 * "constdefs" section in theory files;
  1042 
  1043 * "primrec" section (HOL) no longer requires names;
  1044 
  1045 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1046 
  1047 
  1048 
  1049 New in Isabelle94-5
  1050 -------------------
  1051 
  1052 * reduced space requirements;
  1053 
  1054 * automatic HTML generation from theories;
  1055 
  1056 * theory files no longer require "..." (quotes) around most types;
  1057 
  1058 * new examples, including two proofs of the Church-Rosser theorem;
  1059 
  1060 * non-curried (1994) version of HOL is no longer distributed;
  1061 
  1062 
  1063 
  1064 New in Isabelle94-4
  1065 -------------------
  1066 
  1067 * greatly reduced space requirements;
  1068 
  1069 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1070 
  1071 * searchable theorem database (see the section "Retrieving theorems" on
  1072 page 8 of the Reference Manual);
  1073 
  1074 * new examples, including Grabczewski's monumental case study of the
  1075 Axiom of Choice;
  1076 
  1077 * The previous version of HOL renamed to Old_HOL;
  1078 
  1079 * The new version of HOL (previously called CHOL) uses a curried syntax
  1080 for functions.  Application looks like f a b instead of f(a,b);
  1081 
  1082 * Mutually recursive inductive definitions finally work in HOL;
  1083 
  1084 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1085 translates to the operator "split";
  1086 
  1087 
  1088 
  1089 New in Isabelle94-3
  1090 -------------------
  1091 
  1092 * new infix operator, addss, allowing the classical reasoner to
  1093 perform simplification at each step of its search.  Example:
  1094         fast_tac (cs addss ss)
  1095 
  1096 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1097 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1098 look like (a,b) instead of <a,b>;
  1099 
  1100 * PLEASE NOTE: CHOL will eventually replace HOL!
  1101 
  1102 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1103 It translates to the operator "split".  A new theory of integers is available;
  1104 
  1105 * In ZF, integer numerals now denote two's-complement binary integers.
  1106 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1107 
  1108 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1109 of the Axiom of Choice;
  1110 
  1111 
  1112 
  1113 New in Isabelle94-2
  1114 -------------------
  1115 
  1116 * Significantly faster resolution;
  1117 
  1118 * the different sections in a .thy file can now be mixed and repeated
  1119 freely;
  1120 
  1121 * Database of theorems for FOL, HOL and ZF.  New
  1122 commands including qed, qed_goal and bind_thm store theorems in the database.
  1123 
  1124 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1125 a given theory (thms_of), or find out what theory a theorem was proved in
  1126 (theory_of_thm);
  1127 
  1128 * Bugs fixed in the inductive definition and datatype packages;
  1129 
  1130 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1131 and HOL_dup_cs obsolete;
  1132 
  1133 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1134 have been removed;
  1135 
  1136 * Simpler definition of function space in ZF;
  1137 
  1138 * new results about cardinal and ordinal arithmetic in ZF;
  1139 
  1140 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1141 types;
  1142 
  1143 
  1144 $Id$