NEWS
author wenzelm
Mon Aug 23 16:51:48 1999 +0200 (1999-08-23)
changeset 7327 596318fdb379
parent 7326 a1555491a966
child 7420 cba45c114f3b
permissions -rw-r--r--
tuned;
     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 
   104 *** HOL ***
   105 
   106 ** HOL arithmetic **
   107 
   108 * There are now decision procedures for linear arithmetic over nat and
   109 int:
   110 
   111 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   112 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   113 are treated as atomic; subformulae not involving type `nat' or `int'
   114 are ignored; quantified subformulae are ignored unless they are
   115 positive universal or negative existential. The tactic has to be
   116 invoked by hand and can be a little bit slow. In particular, the
   117 running time is exponential in the number of occurrences of `min' and
   118 `max', and `-' on `nat'.
   119 
   120 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   121 (negated) (in)equalities among the premises and the conclusion into
   122 account (i.e. no compound formulae) and does not know about `min' and
   123 `max', and `-' on `nat'. It is fast and is used automatically by the
   124 simplifier.
   125 
   126 NB: At the moment, these decision procedures do not cope with mixed
   127 nat/int formulae where the two parts interact, such as `m < n ==>
   128 int(m) < int(n)'.
   129 
   130 * HOL/Numeral provides a generic theory of numerals (encoded
   131 efficiently as bit strings); setup for types nat/int/real is in place;
   132 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   133 int, existing theories and proof scripts may require a few additional
   134 type constraints;
   135 
   136 * integer division and remainder can now be performed on constant
   137 arguments;
   138 
   139 * many properties of integer multiplication, division and remainder
   140 are now available;
   141 
   142 * An interface to the Stanford Validity Checker (SVC) is available through the
   143 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   144 are proved automatically.  SVC must be installed separately, and its results
   145 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   146 invocation of the underlying oracle).  For SVC see
   147   http://agamemnon.stanford.edu/~levitt/vc/index.html
   148 
   149 * IsaMakefile: the HOL-Real target now builds an actual image;
   150 
   151 
   152 ** HOL misc **
   153 
   154 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   155 -- avoids syntactic ambiguities and treats state, transition, and
   156 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   157 changed syntax and (many) tactics;
   158 
   159 * HOL/datatype: Now also handles arbitrarily branching datatypes
   160   (using function types) such as
   161 
   162   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   163 
   164 * HOL/record: record_simproc (part of the default simpset) takes care
   165 of selectors applied to updated records; record_split_tac is no longer
   166 part of the default claset; update_defs may now be removed from the
   167 simpset in many cases; COMPATIBILITY: old behavior achieved by
   168 
   169   claset_ref () := claset() addSWrapper record_split_wrapper;
   170   Delsimprocs [record_simproc]
   171 
   172 * HOL/typedef: fixed type inference for representing set; type
   173 arguments now have to occur explicitly on the rhs as type constraints;
   174 
   175 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   176 names rather than an ML expression;
   177 
   178 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   179 supplied later.  Program schemes can be defined, such as
   180     "While B C s = (if B s then While B C (C s) else s)"
   181 where the well-founded relation can be chosen after B and C have been given.
   182 
   183 * HOL/List: the constructors of type list are now Nil and Cons;
   184 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   185 course, ML tools referring to List.list.op # etc. have to be adapted;
   186 
   187 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   188 disabled by default; run isabelle with option -m HOL to get back to
   189 the original Gordon/HOL-style output;
   190 
   191 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   192 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   193 
   194 * HOL basic syntax simplified (more orthogonal): all variants of
   195 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   196 Eps operator is provided as well: "SOME x. P[x]";
   197 
   198 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   199 
   200 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   201 thus available for user theories;
   202 
   203 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   204 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   205 time;
   206 
   207 
   208 *** LK ***
   209 
   210 * the notation <<...>> is now available as a notation for sequences of
   211 formulas;
   212 
   213 * the simplifier is now installed
   214 
   215 * the axiom system has been generalized (thanks to Soren Heilmann) 
   216 
   217 * the classical reasoner now has a default rule database
   218 
   219 
   220 *** ZF ***
   221 
   222 * new primrec section allows primitive recursive functions to be given
   223 directly (as in HOL) over datatypes and the natural numbers;
   224 
   225 * new tactics induct_tac and exhaust_tac for induction (or case
   226 analysis) over datatypes and the natural numbers;
   227 
   228 * the datatype declaration of type T now defines the recursor T_rec;
   229 
   230 * simplification automatically does freeness reasoning for datatype
   231 constructors;
   232 
   233 * automatic type-inference, with AddTCs command to insert new
   234 type-checking rules;
   235 
   236 * datatype introduction rules are now added as Safe Introduction rules
   237 to the claset;
   238 
   239 * the syntax "if P then x else y" is now available in addition to
   240 if(P,x,y);
   241 
   242 
   243 *** Internal programming interfaces ***
   244 
   245 * AxClass.axclass_tac lost the theory argument;
   246 
   247 * tuned current_goals_markers semantics: begin / end goal avoids
   248 printing empty lines;
   249 
   250 * removed prs and prs_fn hook, which was broken because it did not
   251 include \n in its semantics, forcing writeln to add one
   252 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   253 string -> unit if you really want to output text without newline;
   254 
   255 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   256 plain output, interface builders may have to enable 'isabelle_font'
   257 mode to get Isabelle font glyphs as before;
   258 
   259 * refined token_translation interface; INCOMPATIBILITY: output length
   260 now of type real instead of int;
   261 
   262 * theory loader actions may be traced via new ThyInfo.add_hook
   263 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   264 your own database of information attached to *whole* theories -- as
   265 opposed to intra-theory data slots offered via TheoryDataFun;
   266 
   267 
   268 
   269 New in Isabelle98-1 (October 1998)
   270 ----------------------------------
   271 
   272 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   273 
   274 * several changes of automated proof tools;
   275 
   276 * HOL: major changes to the inductive and datatype packages, including
   277 some minor incompatibilities of theory syntax;
   278 
   279 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   280 called `inj_on';
   281 
   282 * HOL: removed duplicate thms in Arith:
   283   less_imp_add_less  should be replaced by  trans_less_add1
   284   le_imp_add_le      should be replaced by  trans_le_add1
   285 
   286 * HOL: unary minus is now overloaded (new type constraints may be
   287 required);
   288 
   289 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   290 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   291 now taken as an integer constant.
   292 
   293 * Pure: ML function 'theory_of' renamed to 'theory';
   294 
   295 
   296 *** Proof tools ***
   297 
   298 * Simplifier:
   299   1. Asm_full_simp_tac is now more aggressive.
   300      1. It will sometimes reorient premises if that increases their power to
   301         simplify.
   302      2. It does no longer proceed strictly from left to right but may also
   303         rotate premises to achieve further simplification.
   304      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   305      old Asm_full_simp_tac in that it does not rotate premises.
   306   2. The simplifier now knows a little bit about nat-arithmetic.
   307 
   308 * Classical reasoner: wrapper mechanism for the classical reasoner now
   309 allows for selected deletion of wrappers, by introduction of names for
   310 wrapper functionals.  This implies that addbefore, addSbefore,
   311 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   312 and that adding two tactics with the same name overwrites the first
   313 one (emitting a warning).
   314   type wrapper = (int -> tactic) -> (int -> tactic)
   315   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   316   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   317   delWrapper, delSWrapper: claset *  string            -> claset
   318   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   319 
   320 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   321 semantics; addbefore now affects only the unsafe part of step_tac
   322 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   323 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   324 by Force_tac;
   325 
   326 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   327 compWrapper; added safe wrapper (and access functions for it);
   328 
   329 * HOL/split_all_tac is now much faster and fails if there is nothing
   330 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   331 and the names of the automatically generated variables have changed.
   332 split_all_tac has moved within claset() from unsafe wrappers to safe
   333 wrappers, which means that !!-bound variables are split much more
   334 aggressively, and safe_tac and clarify_tac now split such variables.
   335 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   336 Note: the same holds for record_split_tac, which does the job of
   337 split_all_tac for record fields.
   338 
   339 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   340 permanently to the default simpset using Addsplits just like
   341 Addsimps. They can be removed via Delsplits just like
   342 Delsimps. Lower-case versions are also available.
   343 
   344 * HOL/Simplifier: The rule split_if is now part of the default
   345 simpset. This means that the simplifier will eliminate all occurrences
   346 of if-then-else in the conclusion of a goal. To prevent this, you can
   347 either remove split_if completely from the default simpset by
   348 `Delsplits [split_if]' or remove it in a specific call of the
   349 simplifier using `... delsplits [split_if]'.  You can also add/delete
   350 other case splitting rules to/from the default simpset: every datatype
   351 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   352 t is the name of the datatype).
   353 
   354 * Classical reasoner / Simplifier combination: new force_tac (and
   355 derivatives Force_tac, force) combines rewriting and classical
   356 reasoning (and whatever other tools) similarly to auto_tac, but is
   357 aimed to solve the given subgoal completely.
   358 
   359 
   360 *** General ***
   361 
   362 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   363 and `goalw': the theory is no longer needed as an explicit argument -
   364 the current theory context is used; assumptions are no longer returned
   365 at the ML-level unless one of them starts with ==> or !!; it is
   366 recommended to convert to these new commands using isatool fixgoal
   367 (backup your sources first!);
   368 
   369 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   370 the current theory context, and 'theory' to lookup stored theories;
   371 
   372 * new theory section 'locale' for declaring constants, assumptions and
   373 definitions that have local scope;
   374 
   375 * new theory section 'nonterminals' for purely syntactic types;
   376 
   377 * new theory section 'setup' for generic ML setup functions
   378 (e.g. package initialization);
   379 
   380 * the distribution now includes Isabelle icons: see
   381 lib/logo/isabelle-{small,tiny}.xpm;
   382 
   383 * isatool install - install binaries with absolute references to
   384 ISABELLE_HOME/bin;
   385 
   386 * isatool logo -- create instances of the Isabelle logo (as EPS);
   387 
   388 * print mode 'emacs' reserved for Isamode;
   389 
   390 * support multiple print (ast) translations per constant name;
   391 
   392 * theorems involving oracles are now printed with a suffixed [!];
   393 
   394 
   395 *** HOL ***
   396 
   397 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   398 
   399 * HOL/inductive package reorganized and improved: now supports mutual
   400 definitions such as
   401 
   402   inductive EVEN ODD
   403     intrs
   404       null "0 : EVEN"
   405       oddI "n : EVEN ==> Suc n : ODD"
   406       evenI "n : ODD ==> Suc n : EVEN"
   407 
   408 new theorem list "elims" contains an elimination rule for each of the
   409 recursive sets; inductive definitions now handle disjunctive premises
   410 correctly (also ZF);
   411 
   412 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   413 "mutual_induct" no longer exists - the induction rule is always
   414 contained in "induct";
   415 
   416 
   417 * HOL/datatype package re-implemented and greatly improved: now
   418 supports mutually recursive datatypes such as
   419 
   420   datatype
   421     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   422             | SUM ('a aexp) ('a aexp)
   423             | DIFF ('a aexp) ('a aexp)
   424             | NUM 'a
   425   and
   426     'a bexp = LESS ('a aexp) ('a aexp)
   427             | AND ('a bexp) ('a bexp)
   428             | OR ('a bexp) ('a bexp)
   429 
   430 as well as indirectly recursive datatypes such as
   431 
   432   datatype
   433     ('a, 'b) term = Var 'a
   434                   | App 'b ((('a, 'b) term) list)
   435 
   436 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   437 induction on mutually / indirectly recursive datatypes.
   438 
   439 Primrec equations are now stored in theory and can be accessed via
   440 <function_name>.simps.
   441 
   442 INCOMPATIBILITIES:
   443 
   444   - Theories using datatypes must now have theory Datatype as an
   445     ancestor.
   446   - The specific <typename>.induct_tac no longer exists - use the
   447     generic induct_tac instead.
   448   - natE has been renamed to nat.exhaust - use exhaust_tac
   449     instead of res_inst_tac ... natE. Note that the variable
   450     names in nat.exhaust differ from the names in natE, this
   451     may cause some "fragile" proofs to fail.
   452   - The theorems split_<typename>_case and split_<typename>_case_asm
   453     have been renamed to <typename>.split and <typename>.split_asm.
   454   - Since default sorts of type variables are now handled correctly,
   455     some datatype definitions may have to be annotated with explicit
   456     sort constraints.
   457   - Primrec definitions no longer require function name and type
   458     of recursive argument.
   459 
   460 Consider using isatool fixdatatype to adapt your theories and proof
   461 scripts to the new package (backup your sources first!).
   462 
   463 
   464 * HOL/record package: considerably improved implementation; now
   465 includes concrete syntax for record types, terms, updates; theorems
   466 for surjective pairing and splitting !!-bound record variables; proof
   467 support is as follows:
   468 
   469   1) standard conversions (selectors or updates applied to record
   470 constructor terms) are part of the standard simpset;
   471 
   472   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   473 made part of standard simpset and claset via addIffs;
   474 
   475   3) a tactic for record field splitting (record_split_tac) is part of
   476 the standard claset (addSWrapper);
   477 
   478 To get a better idea about these rules you may retrieve them via
   479 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   480 the name of your record type.
   481 
   482 The split tactic 3) conceptually simplifies by the following rule:
   483 
   484   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   485 
   486 Thus any record variable that is bound by meta-all will automatically
   487 blow up into some record constructor term, consequently the
   488 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   489 solve record problems automatically.
   490 
   491 
   492 * reorganized the main HOL image: HOL/Integ and String loaded by
   493 default; theory Main includes everything;
   494 
   495 * automatic simplification of integer sums and comparisons, using cancellation;
   496 
   497 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   498 
   499 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   500 
   501 * many new identities for unions, intersections, set difference, etc.;
   502 
   503 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   504 called split_if, split_split, split_sum_case and split_nat_case (to go
   505 with add/delsplits);
   506 
   507 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   508 (?x::unit) = (); this is made part of the default simpset, which COULD
   509 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   510 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   511 unit_abs_eta_conv is added in order to counter the effect of
   512 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   513 %u.f();
   514 
   515 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   516 makes more sense);
   517 
   518 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   519   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   520   disjointness reasoning but breaking a few old proofs.
   521 
   522 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   523 to 'converse' from 'inverse' (for compatibility with ZF and some
   524 literature);
   525 
   526 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   527 the well-founded relation;
   528 
   529 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   530     Compl A.  The "Compl" syntax remains available as input syntax for this
   531     release ONLY.
   532 
   533 * HOL/Update: new theory of function updates:
   534     f(a:=b) == %x. if x=a then b else f x
   535 may also be iterated as in f(a:=b,c:=d,...);
   536 
   537 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   538 
   539 * HOL/List:
   540   - new function list_update written xs[i:=v] that updates the i-th
   541     list position. May also be iterated as in xs[i:=a,j:=b,...].
   542   - new function `upt' written [i..j(] which generates the list
   543     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   544     bound write [i..j], which is a shorthand for [i..j+1(].
   545   - new lexicographic orderings and corresponding wellfoundedness theorems.
   546 
   547 * HOL/Arith:
   548   - removed 'pred' (predecessor) function;
   549   - generalized some theorems about n-1;
   550   - many new laws about "div" and "mod";
   551   - new laws about greatest common divisors (see theory ex/Primes);
   552 
   553 * HOL/Relation: renamed the relational operator r^-1 "converse"
   554 instead of "inverse";
   555 
   556 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   557   of the multiset ordering;
   558 
   559 * directory HOL/Real: a construction of the reals using Dedekind cuts
   560   (not included by default);
   561 
   562 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   563 
   564 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   565   programs, i.e. different program variables may have different types.
   566 
   567 * calling (stac rew i) now fails if "rew" has no effect on the goal
   568   [previously, this check worked only if the rewrite rule was unconditional]
   569   Now rew can involve either definitions or equalities (either == or =).
   570 
   571 
   572 *** ZF ***
   573 
   574 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   575   only the theorems proved on ZF.ML;
   576 
   577 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   578   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   579   disjointness reasoning but breaking a few old proofs.
   580 
   581 * ZF/Update: new theory of function updates
   582     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   583   may also be iterated as in f(a:=b,c:=d,...);
   584 
   585 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   586 
   587 * calling (stac rew i) now fails if "rew" has no effect on the goal
   588   [previously, this check worked only if the rewrite rule was unconditional]
   589   Now rew can involve either definitions or equalities (either == or =).
   590 
   591 * case_tac provided for compatibility with HOL
   592     (like the old excluded_middle_tac, but with subgoals swapped)
   593 
   594 
   595 *** Internal programming interfaces ***
   596 
   597 * Pure: several new basic modules made available for general use, see
   598 also src/Pure/README;
   599 
   600 * improved the theory data mechanism to support encapsulation (data
   601 kind name replaced by private Object.kind, acting as authorization
   602 key); new type-safe user interface via functor TheoryDataFun; generic
   603 print_data function becomes basically useless;
   604 
   605 * removed global_names compatibility flag -- all theory declarations
   606 are qualified by default;
   607 
   608 * module Pure/Syntax now offers quote / antiquote translation
   609 functions (useful for Hoare logic etc. with implicit dependencies);
   610 see HOL/ex/Antiquote for an example use;
   611 
   612 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   613 cterm -> thm;
   614 
   615 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   616 subgoal;
   617 
   618 * Display.print_goals function moved to Locale.print_goals;
   619 
   620 * standard print function for goals supports current_goals_markers
   621 variable for marking begin of proof, end of proof, start of goal; the
   622 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   623 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   624 for example;
   625 
   626 
   627 
   628 New in Isabelle98 (January 1998)
   629 --------------------------------
   630 
   631 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   632 
   633 * changed lexical syntax of terms / types: dots made part of long
   634 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   635 
   636 * simpset (and claset) reference variable replaced by functions
   637 simpset / simpset_ref;
   638 
   639 * no longer supports theory aliases (via merge) and non-trivial
   640 implicit merge of thms' signatures;
   641 
   642 * most internal names of constants changed due to qualified names;
   643 
   644 * changed Pure/Sequence interface (see Pure/seq.ML);
   645 
   646 
   647 *** General Changes ***
   648 
   649 * hierachically structured name spaces (for consts, types, axms, thms
   650 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   651 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   652 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   653 long_names for fully qualified output names; NOTE: ML programs
   654 (special tactics, packages etc.) referring to internal names may have
   655 to be adapted to cope with fully qualified names; in case of severe
   656 backward campatibility problems try setting 'global_names' at compile
   657 time to have enrything declared within a flat name space; one may also
   658 fine tune name declarations in theories via the 'global' and 'local'
   659 section;
   660 
   661 * reimplemented the implicit simpset and claset using the new anytype
   662 data filed in signatures; references simpset:simpset ref etc. are
   663 replaced by functions simpset:unit->simpset and
   664 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   665 to patch your ML files accordingly;
   666 
   667 * HTML output now includes theory graph data for display with Java
   668 applet or isatool browser; data generated automatically via isatool
   669 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   670 
   671 * defs may now be conditional; improved rewrite_goals_tac to handle
   672 conditional equations;
   673 
   674 * defs now admits additional type arguments, using TYPE('a) syntax;
   675 
   676 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   677 creates a new theory node; implicit merge of thms' signatures is
   678 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   679 transfer:theory->thm->thm in (rare) cases;
   680 
   681 * improved handling of draft signatures / theories; draft thms (and
   682 ctyps, cterms) are automatically promoted to real ones;
   683 
   684 * slightly changed interfaces for oracles: admit many per theory, named
   685 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   686 
   687 * print_goals: optional output of const types (set show_consts and
   688 show_types);
   689 
   690 * improved output of warnings (###) and errors (***);
   691 
   692 * subgoal_tac displays a warning if the new subgoal has type variables;
   693 
   694 * removed old README and Makefiles;
   695 
   696 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   697 
   698 * removed obsolete init_pps and init_database;
   699 
   700 * deleted the obsolete tactical STATE, which was declared by
   701     fun STATE tacfun st = tacfun st st;
   702 
   703 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   704 (which abbreviates $HOME);
   705 
   706 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   707 use isatool fixseq to adapt your ML programs (this works for fully
   708 qualified references to the Sequence structure only!);
   709 
   710 * use_thy no longer requires writable current directory; it always
   711 reloads .ML *and* .thy file, if either one is out of date;
   712 
   713 
   714 *** Classical Reasoner ***
   715 
   716 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   717 tactics that use classical reasoning to simplify a subgoal without
   718 splitting it into several subgoals;
   719 
   720 * Safe_tac: like safe_tac but uses the default claset;
   721 
   722 
   723 *** Simplifier ***
   724 
   725 * added simplification meta rules:
   726     (asm_)(full_)simplify: simpset -> thm -> thm;
   727 
   728 * simplifier.ML no longer part of Pure -- has to be loaded by object
   729 logics (again);
   730 
   731 * added prems argument to simplification procedures;
   732 
   733 * HOL, FOL, ZF: added infix function `addsplits':
   734   instead of `<simpset> setloop (split_tac <thms>)'
   735   you can simply write `<simpset> addsplits <thms>'
   736 
   737 
   738 *** Syntax ***
   739 
   740 * TYPE('a) syntax for type reflection terms;
   741 
   742 * no longer handles consts with name "" -- declare as 'syntax' instead;
   743 
   744 * pretty printer: changed order of mixfix annotation preference (again!);
   745 
   746 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   747 
   748 
   749 *** HOL ***
   750 
   751 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   752   with `addloop' of the simplifier to faciliate case splitting in premises.
   753 
   754 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   755 
   756 * HOL/Auth: new protocol proofs including some for the Internet
   757   protocol TLS;
   758 
   759 * HOL/Map: new theory of `maps' a la VDM;
   760 
   761 * HOL/simplifier: simplification procedures nat_cancel_sums for
   762 cancelling out common nat summands from =, <, <= (in)equalities, or
   763 differences; simplification procedures nat_cancel_factor for
   764 cancelling common factor from =, <, <= (in)equalities over natural
   765 sums; nat_cancel contains both kinds of procedures, it is installed by
   766 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   767 
   768 * HOL/simplifier: terms of the form
   769   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   770   are rewritten to
   771   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   772   and those of the form
   773   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   774   are rewritten to
   775   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   776 
   777 * HOL/datatype
   778   Each datatype `t' now comes with a theorem `split_t_case' of the form
   779 
   780   P(t_case f1 ... fn x) =
   781      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   782         ...
   783        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   784      )
   785 
   786   and a theorem `split_t_case_asm' of the form
   787 
   788   P(t_case f1 ... fn x) =
   789     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   790         ...
   791        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   792      )
   793   which can be added to a simpset via `addsplits'. The existing theorems
   794   expand_list_case and expand_option_case have been renamed to
   795   split_list_case and split_option_case.
   796 
   797 * HOL/Arithmetic:
   798   - `pred n' is automatically converted to `n-1'.
   799     Users are strongly encouraged not to use `pred' any longer,
   800     because it will disappear altogether at some point.
   801   - Users are strongly encouraged to write "0 < n" rather than
   802     "n ~= 0". Theorems and proof tools have been modified towards this
   803     `standard'.
   804 
   805 * HOL/Lists:
   806   the function "set_of_list" has been renamed "set" (and its theorems too);
   807   the function "nth" now takes its arguments in the reverse order and
   808   has acquired the infix notation "!" as in "xs!n".
   809 
   810 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   811 
   812 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   813   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   814 
   815 * HOL/record: extensible records with schematic structural subtyping
   816 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   817 still lacks various theorems and concrete record syntax;
   818 
   819 
   820 *** HOLCF ***
   821 
   822 * removed "axioms" and "generated by" sections;
   823 
   824 * replaced "ops" section by extended "consts" section, which is capable of
   825   handling the continuous function space "->" directly;
   826 
   827 * domain package:
   828   . proves theorems immediately and stores them in the theory,
   829   . creates hierachical name space,
   830   . now uses normal mixfix annotations (instead of cinfix...),
   831   . minor changes to some names and values (for consistency),
   832   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   833   . separator between mutual domain defs: changed "," to "and",
   834   . improved handling of sort constraints;  now they have to
   835     appear on the left-hand side of the equations only;
   836 
   837 * fixed LAM <x,y,zs>.b syntax;
   838 
   839 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   840 adm (%x. P (t x)), where P is chainfinite and t continuous;
   841 
   842 
   843 *** FOL and ZF ***
   844 
   845 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   846   with `addloop' of the simplifier to faciliate case splitting in premises.
   847 
   848 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   849 in HOL, they strip ALL and --> from proved theorems;
   850 
   851 
   852 
   853 New in Isabelle94-8 (May 1997)
   854 ------------------------------
   855 
   856 *** General Changes ***
   857 
   858 * new utilities to build / run / maintain Isabelle etc. (in parts
   859 still somewhat experimental); old Makefiles etc. still functional;
   860 
   861 * new 'Isabelle System Manual';
   862 
   863 * INSTALL text, together with ./configure and ./build scripts;
   864 
   865 * reimplemented type inference for greater efficiency, better error
   866 messages and clean internal interface;
   867 
   868 * prlim command for dealing with lots of subgoals (an easier way of
   869 setting goals_limit);
   870 
   871 
   872 *** Syntax ***
   873 
   874 * supports alternative (named) syntax tables (parser and pretty
   875 printer); internal interface is provided by add_modesyntax(_i);
   876 
   877 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   878 be used in conjunction with the Isabelle symbol font; uses the
   879 "symbols" syntax table;
   880 
   881 * added token_translation interface (may translate name tokens in
   882 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   883 the current print_mode); IMPORTANT: user print translation functions
   884 are responsible for marking newly introduced bounds
   885 (Syntax.mark_boundT);
   886 
   887 * token translations for modes "xterm" and "xterm_color" that display
   888 names in bold, underline etc. or colors (which requires a color
   889 version of xterm);
   890 
   891 * infixes may now be declared with names independent of their syntax;
   892 
   893 * added typed_print_translation (like print_translation, but may
   894 access type of constant);
   895 
   896 
   897 *** Classical Reasoner ***
   898 
   899 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   900 some limitations.  Blast_tac...
   901   + ignores addss, addbefore, addafter; this restriction is intrinsic
   902   + ignores elimination rules that don't have the correct format
   903         (the conclusion MUST be a formula variable)
   904   + ignores types, which can make HOL proofs fail
   905   + rules must not require higher-order unification, e.g. apply_type in ZF
   906     [message "Function Var's argument not a bound variable" relates to this]
   907   + its proof strategy is more general but can actually be slower
   908 
   909 * substitution with equality assumptions no longer permutes other
   910 assumptions;
   911 
   912 * minor changes in semantics of addafter (now called addaltern); renamed
   913 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   914 (and access functions for it);
   915 
   916 * improved combination of classical reasoner and simplifier:
   917   + functions for handling clasimpsets
   918   + improvement of addss: now the simplifier is called _after_ the
   919     safe steps.
   920   + safe variant of addss called addSss: uses safe simplifications
   921     _during_ the safe steps. It is more complete as it allows multiple
   922     instantiations of unknowns (e.g. with slow_tac).
   923 
   924 *** Simplifier ***
   925 
   926 * added interface for simplification procedures (functions that
   927 produce *proven* rewrite rules on the fly, depending on current
   928 redex);
   929 
   930 * ordering on terms as parameter (used for ordered rewriting);
   931 
   932 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   933 
   934 * the solver is now split into a safe and an unsafe part.
   935 This should be invisible for the normal user, except that the
   936 functions setsolver and addsolver have been renamed to setSolver and
   937 addSolver; added safe_asm_full_simp_tac;
   938 
   939 
   940 *** HOL ***
   941 
   942 * a generic induction tactic `induct_tac' which works for all datatypes and
   943 also for type `nat';
   944 
   945 * a generic case distinction tactic `exhaust_tac' which works for all
   946 datatypes and also for type `nat';
   947 
   948 * each datatype comes with a function `size';
   949 
   950 * patterns in case expressions allow tuple patterns as arguments to
   951 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   952 
   953 * primrec now also works with type nat;
   954 
   955 * recdef: a new declaration form, allows general recursive functions to be
   956 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   957 
   958 * the constant for negation has been renamed from "not" to "Not" to
   959 harmonize with FOL, ZF, LK, etc.;
   960 
   961 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   962 infinite lists;
   963 
   964 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   965 
   966 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   967 problems in commutative rings, using axiomatic type classes for + and *;
   968 
   969 * more examples in HOL/MiniML and HOL/Auth;
   970 
   971 * more default rewrite rules for quantifiers, union/intersection;
   972 
   973 * a new constant `arbitrary == @x.False';
   974 
   975 * HOLCF/IOA replaces old HOL/IOA;
   976 
   977 * HOLCF changes: derived all rules and arities
   978   + axiomatic type classes instead of classes
   979   + typedef instead of faking type definitions
   980   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   981   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   982   + eliminated the types void, one, tr
   983   + use unit lift and bool lift (with translations) instead of one and tr
   984   + eliminated blift from Lift3.thy (use Def instead of blift)
   985   all eliminated rules are derived as theorems --> no visible changes ;
   986 
   987 
   988 *** ZF ***
   989 
   990 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   991 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   992 as ZF_cs addSIs [equalityI];
   993 
   994 
   995 
   996 New in Isabelle94-7 (November 96)
   997 ---------------------------------
   998 
   999 * allowing negative levels (as offsets) in prlev and choplev;
  1000 
  1001 * super-linear speedup for large simplifications;
  1002 
  1003 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1004 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1005 FAIL); can suppress it using the command Delsimps (ex_simps @
  1006 all_simps); De Morgan laws are also now included, by default;
  1007 
  1008 * improved printing of ==>  :  ~:
  1009 
  1010 * new object-logic "Sequents" adds linear logic, while replacing LK
  1011 and Modal (thanks to Sara Kalvala);
  1012 
  1013 * HOL/Auth: correctness proofs for authentication protocols;
  1014 
  1015 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1016 examples on HOL/Auth);
  1017 
  1018 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1019 the rewriter and classical reasoner simultaneously;
  1020 
  1021 * function uresult no longer returns theorems in "standard" format;
  1022 regain previous version by: val uresult = standard o uresult;
  1023 
  1024 
  1025 
  1026 New in Isabelle94-6
  1027 -------------------
  1028 
  1029 * oracles -- these establish an interface between Isabelle and trusted
  1030 external reasoners, which may deliver results as theorems;
  1031 
  1032 * proof objects (in particular record all uses of oracles);
  1033 
  1034 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1035 
  1036 * "constdefs" section in theory files;
  1037 
  1038 * "primrec" section (HOL) no longer requires names;
  1039 
  1040 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1041 
  1042 
  1043 
  1044 New in Isabelle94-5
  1045 -------------------
  1046 
  1047 * reduced space requirements;
  1048 
  1049 * automatic HTML generation from theories;
  1050 
  1051 * theory files no longer require "..." (quotes) around most types;
  1052 
  1053 * new examples, including two proofs of the Church-Rosser theorem;
  1054 
  1055 * non-curried (1994) version of HOL is no longer distributed;
  1056 
  1057 
  1058 
  1059 New in Isabelle94-4
  1060 -------------------
  1061 
  1062 * greatly reduced space requirements;
  1063 
  1064 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1065 
  1066 * searchable theorem database (see the section "Retrieving theorems" on
  1067 page 8 of the Reference Manual);
  1068 
  1069 * new examples, including Grabczewski's monumental case study of the
  1070 Axiom of Choice;
  1071 
  1072 * The previous version of HOL renamed to Old_HOL;
  1073 
  1074 * The new version of HOL (previously called CHOL) uses a curried syntax
  1075 for functions.  Application looks like f a b instead of f(a,b);
  1076 
  1077 * Mutually recursive inductive definitions finally work in HOL;
  1078 
  1079 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1080 translates to the operator "split";
  1081 
  1082 
  1083 
  1084 New in Isabelle94-3
  1085 -------------------
  1086 
  1087 * new infix operator, addss, allowing the classical reasoner to
  1088 perform simplification at each step of its search.  Example:
  1089         fast_tac (cs addss ss)
  1090 
  1091 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1092 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1093 look like (a,b) instead of <a,b>;
  1094 
  1095 * PLEASE NOTE: CHOL will eventually replace HOL!
  1096 
  1097 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1098 It translates to the operator "split".  A new theory of integers is available;
  1099 
  1100 * In ZF, integer numerals now denote two's-complement binary integers.
  1101 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1102 
  1103 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1104 of the Axiom of Choice;
  1105 
  1106 
  1107 
  1108 New in Isabelle94-2
  1109 -------------------
  1110 
  1111 * Significantly faster resolution;
  1112 
  1113 * the different sections in a .thy file can now be mixed and repeated
  1114 freely;
  1115 
  1116 * Database of theorems for FOL, HOL and ZF.  New
  1117 commands including qed, qed_goal and bind_thm store theorems in the database.
  1118 
  1119 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1120 a given theory (thms_of), or find out what theory a theorem was proved in
  1121 (theory_of_thm);
  1122 
  1123 * Bugs fixed in the inductive definition and datatype packages;
  1124 
  1125 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1126 and HOL_dup_cs obsolete;
  1127 
  1128 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1129 have been removed;
  1130 
  1131 * Simpler definition of function space in ZF;
  1132 
  1133 * new results about cardinal and ordinal arithmetic in ZF;
  1134 
  1135 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1136 types;
  1137 
  1138 
  1139 $Id$