NEWS
author wenzelm
Wed Sep 29 13:49:07 1999 +0200 (1999-09-29)
changeset 7632 25a0d2ba3a87
parent 7619 d78b8b103fd9
child 7647 2ceddd91cd0a
permissions -rw-r--r--
removed extra shyps error;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     8 
     9 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
    10 are no longer simplified.  (This allows the simplifier to unfold recursive
    11 functional programs.)  To restore the old behaviour, declare
    12 
    13     Delcongs [if_weak_cong];
    14 
    15 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    16 complement;
    17 
    18 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    19 
    20 * HOL/typedef: fixed type inference for representing set; type
    21 arguments now have to occur explicitly on the rhs as type constraints;
    22 
    23 * ZF: The con_defs part of an inductive definition may no longer refer
    24 to constants declared in the same theory;
    25 
    26 * HOL, ZF: the function mk_cases, generated by the inductive
    27 definition package, has lost an argument.  To simplify its result, it
    28 uses the default simpset instead of a supplied list of theorems.
    29 
    30 * HOL/List: the constructors of type list are now Nil and Cons;
    31 
    32 * Simplifier: the type of the infix ML functions
    33 	setSSolver addSSolver setSolver addSolver
    34 is now  simpset * solver -> simpset  where `solver' is a new abstract type
    35 for packaging solvers. A solver is created via
    36 	mk_solver: string -> (thm list -> int -> tactic) -> solver
    37 where the string argument is only a comment.
    38 
    39 *** Proof tools ***
    40 
    41 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
    42 decision procedure for linear arithmetic. Currently it is used for
    43 types `nat', `int', and `real' in HOL (see below); it can, should and
    44 will be instantiated for other types and logics as well.
    45 
    46 * The simplifier now accepts rewrite rules with flexible heads, eg
    47      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
    48   They are applied like any rule with a non-pattern lhs, i.e. by first-order
    49   matching.
    50 
    51 
    52 *** General ***
    53 
    54 * new Isabelle/Isar subsystem provides an alternative to traditional
    55 tactical theorem proving; together with the ProofGeneral/isar user
    56 interface it offers an interactive environment for developing human
    57 readable proof documents (Isar == Intelligible semi-automated
    58 reasoning); see isatool doc isar-ref and
    59 http://isabelle.in.tum.de/Isar/ for more information;
    60 
    61 * native support for Proof General, both for classic Isabelle and
    62 Isabelle/Isar (the latter is slightly better supported and more
    63 robust);
    64 
    65 * Isabelle manuals now also available as PDF;
    66 
    67 * improved browser info generation: better HTML markup (including
    68 colors), graph views in several sizes; isatool usedir now provides a
    69 proper interface for user theories (via -P option);
    70 
    71 * theory loader rewritten from scratch (may not be fully
    72 bug-compatible); old loadpath variable has been replaced by show_path,
    73 add_path, del_path, reset_path functions; new operations such as
    74 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
    75 isatool doc ref);
    76 
    77 * improved isatool install: option -k creates KDE application icon,
    78 option -p DIR installs standalone binaries;
    79 
    80 * added ML_PLATFORM setting (useful for cross-platform installations);
    81 more robust handling of platform specific ML images for SML/NJ;
    82 
    83 * path element specification '~~' refers to '$ISABELLE_HOME';
    84 
    85 * in locales, the "assumes" and "defines" parts may be omitted if
    86 empty;
    87 
    88 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
    89 long arrows);
    90 
    91 * new print_mode "HTML";
    92 
    93 * new flag show_tags controls display of tags of theorems (which are
    94 basically just comments that may be attached by some tools);
    95 
    96 * Isamode 2.6 requires patch to accomodate change of Isabelle font
    97 mode and goal output format:
    98 
    99 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   100 244c244
   101 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   102 ---
   103 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   104 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   105 181c181
   106 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   107 ---
   108 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   109 
   110 * function bind_thms stores lists of theorems (cf. bind_thm);
   111 
   112 * new shorthand tactics ftac, eatac, datac, fatac;
   113 
   114 * qed (and friends) now accept "" as result name; in that case the
   115 result is not stored, but proper checks and presentation of the result
   116 still apply;
   117 
   118 
   119 *** HOL ***
   120 
   121 ** HOL arithmetic **
   122 
   123 * There are now decision procedures for linear arithmetic over nat and
   124 int:
   125 
   126 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   127 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   128 are treated as atomic; subformulae not involving type `nat' or `int'
   129 are ignored; quantified subformulae are ignored unless they are
   130 positive universal or negative existential. The tactic has to be
   131 invoked by hand and can be a little bit slow. In particular, the
   132 running time is exponential in the number of occurrences of `min' and
   133 `max', and `-' on `nat'.
   134 
   135 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   136 (negated) (in)equalities among the premises and the conclusion into
   137 account (i.e. no compound formulae) and does not know about `min' and
   138 `max', and `-' on `nat'. It is fast and is used automatically by the
   139 simplifier.
   140 
   141 NB: At the moment, these decision procedures do not cope with mixed
   142 nat/int formulae where the two parts interact, such as `m < n ==>
   143 int(m) < int(n)'.
   144 
   145 * HOL/Numeral provides a generic theory of numerals (encoded
   146 efficiently as bit strings); setup for types nat/int/real is in place;
   147 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   148 int, existing theories and proof scripts may require a few additional
   149 type constraints;
   150 
   151 * integer division and remainder can now be performed on constant
   152 arguments;
   153 
   154 * many properties of integer multiplication, division and remainder
   155 are now available;
   156 
   157 * An interface to the Stanford Validity Checker (SVC) is available through the
   158 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   159 are proved automatically.  SVC must be installed separately, and its results
   160 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   161 invocation of the underlying oracle).  For SVC see
   162   http://verify.stanford.edu/SVC
   163 
   164 * IsaMakefile: the HOL-Real target now builds an actual image;
   165 
   166 
   167 ** HOL misc **
   168 
   169 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   170 (in Isabelle/Isar) -- by Gertrud Bauer;
   171 
   172 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   173 -- avoids syntactic ambiguities and treats state, transition, and
   174 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   175 changed syntax and (many) tactics;
   176 
   177 * HOL/datatype: Now also handles arbitrarily branching datatypes
   178   (using function types) such as
   179 
   180   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   181 
   182 * HOL/record: record_simproc (part of the default simpset) takes care
   183 of selectors applied to updated records; record_split_tac is no longer
   184 part of the default claset; update_defs may now be removed from the
   185 simpset in many cases; COMPATIBILITY: old behavior achieved by
   186 
   187   claset_ref () := claset() addSWrapper record_split_wrapper;
   188   Delsimprocs [record_simproc]
   189 
   190 * HOL/typedef: fixed type inference for representing set; type
   191 arguments now have to occur explicitly on the rhs as type constraints;
   192 
   193 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   194 names rather than an ML expression;
   195 
   196 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   197 supplied later.  Program schemes can be defined, such as
   198     "While B C s = (if B s then While B C (C s) else s)"
   199 where the well-founded relation can be chosen after B and C have been given.
   200 
   201 * HOL/List: the constructors of type list are now Nil and Cons;
   202 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   203 course, ML tools referring to List.list.op # etc. have to be adapted;
   204 
   205 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   206 disabled by default; run isabelle with option -m HOL to get back to
   207 the original Gordon/HOL-style output;
   208 
   209 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   210 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   211 
   212 * HOL basic syntax simplified (more orthogonal): all variants of
   213 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   214 Eps operator is provided as well: "SOME x. P[x]";
   215 
   216 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   217 
   218 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   219 thus available for user theories;
   220 
   221 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   222 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   223 time;
   224 
   225 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec several
   226   times and then mp
   227 
   228 
   229 *** LK ***
   230 
   231 * the notation <<...>> is now available as a notation for sequences of
   232 formulas;
   233 
   234 * the simplifier is now installed
   235 
   236 * the axiom system has been generalized (thanks to Soren Heilmann) 
   237 
   238 * the classical reasoner now has a default rule database
   239 
   240 
   241 *** ZF ***
   242 
   243 * new primrec section allows primitive recursive functions to be given
   244 directly (as in HOL) over datatypes and the natural numbers;
   245 
   246 * new tactics induct_tac and exhaust_tac for induction (or case
   247 analysis) over datatypes and the natural numbers;
   248 
   249 * the datatype declaration of type T now defines the recursor T_rec;
   250 
   251 * simplification automatically does freeness reasoning for datatype
   252 constructors;
   253 
   254 * automatic type-inference, with AddTCs command to insert new
   255 type-checking rules;
   256 
   257 * datatype introduction rules are now added as Safe Introduction rules
   258 to the claset;
   259 
   260 * the syntax "if P then x else y" is now available in addition to
   261 if(P,x,y);
   262 
   263 
   264 *** Internal programming interfaces ***
   265 
   266 * structures Vartab / Termtab (instances of TableFun) offer efficient
   267 tables indexed by indexname_ord / term_ord (compatible with aconv);
   268 
   269 * AxClass.axclass_tac lost the theory argument;
   270 
   271 * tuned current_goals_markers semantics: begin / end goal avoids
   272 printing empty lines;
   273 
   274 * removed prs and prs_fn hook, which was broken because it did not
   275 include \n in its semantics, forcing writeln to add one
   276 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   277 string -> unit if you really want to output text without newline;
   278 
   279 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   280 plain output, interface builders may have to enable 'isabelle_font'
   281 mode to get Isabelle font glyphs as before;
   282 
   283 * refined token_translation interface; INCOMPATIBILITY: output length
   284 now of type real instead of int;
   285 
   286 * theory loader actions may be traced via new ThyInfo.add_hook
   287 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   288 your own database of information attached to *whole* theories -- as
   289 opposed to intra-theory data slots offered via TheoryDataFun;
   290 
   291 
   292 
   293 New in Isabelle98-1 (October 1998)
   294 ----------------------------------
   295 
   296 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   297 
   298 * several changes of automated proof tools;
   299 
   300 * HOL: major changes to the inductive and datatype packages, including
   301 some minor incompatibilities of theory syntax;
   302 
   303 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   304 called `inj_on';
   305 
   306 * HOL: removed duplicate thms in Arith:
   307   less_imp_add_less  should be replaced by  trans_less_add1
   308   le_imp_add_le      should be replaced by  trans_le_add1
   309 
   310 * HOL: unary minus is now overloaded (new type constraints may be
   311 required);
   312 
   313 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   314 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   315 now taken as an integer constant.
   316 
   317 * Pure: ML function 'theory_of' renamed to 'theory';
   318 
   319 
   320 *** Proof tools ***
   321 
   322 * Simplifier:
   323   1. Asm_full_simp_tac is now more aggressive.
   324      1. It will sometimes reorient premises if that increases their power to
   325         simplify.
   326      2. It does no longer proceed strictly from left to right but may also
   327         rotate premises to achieve further simplification.
   328      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   329      old Asm_full_simp_tac in that it does not rotate premises.
   330   2. The simplifier now knows a little bit about nat-arithmetic.
   331 
   332 * Classical reasoner: wrapper mechanism for the classical reasoner now
   333 allows for selected deletion of wrappers, by introduction of names for
   334 wrapper functionals.  This implies that addbefore, addSbefore,
   335 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   336 and that adding two tactics with the same name overwrites the first
   337 one (emitting a warning).
   338   type wrapper = (int -> tactic) -> (int -> tactic)
   339   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   340   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   341   delWrapper, delSWrapper: claset *  string            -> claset
   342   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   343 
   344 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   345 semantics; addbefore now affects only the unsafe part of step_tac
   346 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   347 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   348 by Force_tac;
   349 
   350 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   351 compWrapper; added safe wrapper (and access functions for it);
   352 
   353 * HOL/split_all_tac is now much faster and fails if there is nothing
   354 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   355 and the names of the automatically generated variables have changed.
   356 split_all_tac has moved within claset() from unsafe wrappers to safe
   357 wrappers, which means that !!-bound variables are split much more
   358 aggressively, and safe_tac and clarify_tac now split such variables.
   359 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   360 Note: the same holds for record_split_tac, which does the job of
   361 split_all_tac for record fields.
   362 
   363 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   364 permanently to the default simpset using Addsplits just like
   365 Addsimps. They can be removed via Delsplits just like
   366 Delsimps. Lower-case versions are also available.
   367 
   368 * HOL/Simplifier: The rule split_if is now part of the default
   369 simpset. This means that the simplifier will eliminate all occurrences
   370 of if-then-else in the conclusion of a goal. To prevent this, you can
   371 either remove split_if completely from the default simpset by
   372 `Delsplits [split_if]' or remove it in a specific call of the
   373 simplifier using `... delsplits [split_if]'.  You can also add/delete
   374 other case splitting rules to/from the default simpset: every datatype
   375 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   376 t is the name of the datatype).
   377 
   378 * Classical reasoner / Simplifier combination: new force_tac (and
   379 derivatives Force_tac, force) combines rewriting and classical
   380 reasoning (and whatever other tools) similarly to auto_tac, but is
   381 aimed to solve the given subgoal completely.
   382 
   383 
   384 *** General ***
   385 
   386 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   387 and `goalw': the theory is no longer needed as an explicit argument -
   388 the current theory context is used; assumptions are no longer returned
   389 at the ML-level unless one of them starts with ==> or !!; it is
   390 recommended to convert to these new commands using isatool fixgoal
   391 (backup your sources first!);
   392 
   393 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   394 the current theory context, and 'theory' to lookup stored theories;
   395 
   396 * new theory section 'locale' for declaring constants, assumptions and
   397 definitions that have local scope;
   398 
   399 * new theory section 'nonterminals' for purely syntactic types;
   400 
   401 * new theory section 'setup' for generic ML setup functions
   402 (e.g. package initialization);
   403 
   404 * the distribution now includes Isabelle icons: see
   405 lib/logo/isabelle-{small,tiny}.xpm;
   406 
   407 * isatool install - install binaries with absolute references to
   408 ISABELLE_HOME/bin;
   409 
   410 * isatool logo -- create instances of the Isabelle logo (as EPS);
   411 
   412 * print mode 'emacs' reserved for Isamode;
   413 
   414 * support multiple print (ast) translations per constant name;
   415 
   416 * theorems involving oracles are now printed with a suffixed [!];
   417 
   418 
   419 *** HOL ***
   420 
   421 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   422 
   423 * HOL/inductive package reorganized and improved: now supports mutual
   424 definitions such as
   425 
   426   inductive EVEN ODD
   427     intrs
   428       null "0 : EVEN"
   429       oddI "n : EVEN ==> Suc n : ODD"
   430       evenI "n : ODD ==> Suc n : EVEN"
   431 
   432 new theorem list "elims" contains an elimination rule for each of the
   433 recursive sets; inductive definitions now handle disjunctive premises
   434 correctly (also ZF);
   435 
   436 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   437 "mutual_induct" no longer exists - the induction rule is always
   438 contained in "induct";
   439 
   440 
   441 * HOL/datatype package re-implemented and greatly improved: now
   442 supports mutually recursive datatypes such as
   443 
   444   datatype
   445     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   446             | SUM ('a aexp) ('a aexp)
   447             | DIFF ('a aexp) ('a aexp)
   448             | NUM 'a
   449   and
   450     'a bexp = LESS ('a aexp) ('a aexp)
   451             | AND ('a bexp) ('a bexp)
   452             | OR ('a bexp) ('a bexp)
   453 
   454 as well as indirectly recursive datatypes such as
   455 
   456   datatype
   457     ('a, 'b) term = Var 'a
   458                   | App 'b ((('a, 'b) term) list)
   459 
   460 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   461 induction on mutually / indirectly recursive datatypes.
   462 
   463 Primrec equations are now stored in theory and can be accessed via
   464 <function_name>.simps.
   465 
   466 INCOMPATIBILITIES:
   467 
   468   - Theories using datatypes must now have theory Datatype as an
   469     ancestor.
   470   - The specific <typename>.induct_tac no longer exists - use the
   471     generic induct_tac instead.
   472   - natE has been renamed to nat.exhaust - use exhaust_tac
   473     instead of res_inst_tac ... natE. Note that the variable
   474     names in nat.exhaust differ from the names in natE, this
   475     may cause some "fragile" proofs to fail.
   476   - The theorems split_<typename>_case and split_<typename>_case_asm
   477     have been renamed to <typename>.split and <typename>.split_asm.
   478   - Since default sorts of type variables are now handled correctly,
   479     some datatype definitions may have to be annotated with explicit
   480     sort constraints.
   481   - Primrec definitions no longer require function name and type
   482     of recursive argument.
   483 
   484 Consider using isatool fixdatatype to adapt your theories and proof
   485 scripts to the new package (backup your sources first!).
   486 
   487 
   488 * HOL/record package: considerably improved implementation; now
   489 includes concrete syntax for record types, terms, updates; theorems
   490 for surjective pairing and splitting !!-bound record variables; proof
   491 support is as follows:
   492 
   493   1) standard conversions (selectors or updates applied to record
   494 constructor terms) are part of the standard simpset;
   495 
   496   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   497 made part of standard simpset and claset via addIffs;
   498 
   499   3) a tactic for record field splitting (record_split_tac) is part of
   500 the standard claset (addSWrapper);
   501 
   502 To get a better idea about these rules you may retrieve them via
   503 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   504 the name of your record type.
   505 
   506 The split tactic 3) conceptually simplifies by the following rule:
   507 
   508   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   509 
   510 Thus any record variable that is bound by meta-all will automatically
   511 blow up into some record constructor term, consequently the
   512 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   513 solve record problems automatically.
   514 
   515 
   516 * reorganized the main HOL image: HOL/Integ and String loaded by
   517 default; theory Main includes everything;
   518 
   519 * automatic simplification of integer sums and comparisons, using cancellation;
   520 
   521 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   522 
   523 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   524 
   525 * many new identities for unions, intersections, set difference, etc.;
   526 
   527 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   528 called split_if, split_split, split_sum_case and split_nat_case (to go
   529 with add/delsplits);
   530 
   531 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   532 (?x::unit) = (); this is made part of the default simpset, which COULD
   533 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   534 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   535 unit_abs_eta_conv is added in order to counter the effect of
   536 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   537 %u.f();
   538 
   539 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   540 makes more sense);
   541 
   542 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   543   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   544   disjointness reasoning but breaking a few old proofs.
   545 
   546 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   547 to 'converse' from 'inverse' (for compatibility with ZF and some
   548 literature);
   549 
   550 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   551 the well-founded relation;
   552 
   553 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   554     Compl A.  The "Compl" syntax remains available as input syntax for this
   555     release ONLY.
   556 
   557 * HOL/Update: new theory of function updates:
   558     f(a:=b) == %x. if x=a then b else f x
   559 may also be iterated as in f(a:=b,c:=d,...);
   560 
   561 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   562 
   563 * HOL/List:
   564   - new function list_update written xs[i:=v] that updates the i-th
   565     list position. May also be iterated as in xs[i:=a,j:=b,...].
   566   - new function `upt' written [i..j(] which generates the list
   567     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   568     bound write [i..j], which is a shorthand for [i..j+1(].
   569   - new lexicographic orderings and corresponding wellfoundedness theorems.
   570 
   571 * HOL/Arith:
   572   - removed 'pred' (predecessor) function;
   573   - generalized some theorems about n-1;
   574   - many new laws about "div" and "mod";
   575   - new laws about greatest common divisors (see theory ex/Primes);
   576 
   577 * HOL/Relation: renamed the relational operator r^-1 "converse"
   578 instead of "inverse";
   579 
   580 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   581   of the multiset ordering;
   582 
   583 * directory HOL/Real: a construction of the reals using Dedekind cuts
   584   (not included by default);
   585 
   586 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   587 
   588 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   589   programs, i.e. different program variables may have different types.
   590 
   591 * calling (stac rew i) now fails if "rew" has no effect on the goal
   592   [previously, this check worked only if the rewrite rule was unconditional]
   593   Now rew can involve either definitions or equalities (either == or =).
   594 
   595 
   596 *** ZF ***
   597 
   598 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   599   only the theorems proved on ZF.ML;
   600 
   601 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   602   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   603   disjointness reasoning but breaking a few old proofs.
   604 
   605 * ZF/Update: new theory of function updates
   606     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   607   may also be iterated as in f(a:=b,c:=d,...);
   608 
   609 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   610 
   611 * calling (stac rew i) now fails if "rew" has no effect on the goal
   612   [previously, this check worked only if the rewrite rule was unconditional]
   613   Now rew can involve either definitions or equalities (either == or =).
   614 
   615 * case_tac provided for compatibility with HOL
   616     (like the old excluded_middle_tac, but with subgoals swapped)
   617 
   618 
   619 *** Internal programming interfaces ***
   620 
   621 * Pure: several new basic modules made available for general use, see
   622 also src/Pure/README;
   623 
   624 * improved the theory data mechanism to support encapsulation (data
   625 kind name replaced by private Object.kind, acting as authorization
   626 key); new type-safe user interface via functor TheoryDataFun; generic
   627 print_data function becomes basically useless;
   628 
   629 * removed global_names compatibility flag -- all theory declarations
   630 are qualified by default;
   631 
   632 * module Pure/Syntax now offers quote / antiquote translation
   633 functions (useful for Hoare logic etc. with implicit dependencies);
   634 see HOL/ex/Antiquote for an example use;
   635 
   636 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   637 cterm -> thm;
   638 
   639 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   640 subgoal;
   641 
   642 * Display.print_goals function moved to Locale.print_goals;
   643 
   644 * standard print function for goals supports current_goals_markers
   645 variable for marking begin of proof, end of proof, start of goal; the
   646 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   647 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   648 for example;
   649 
   650 
   651 
   652 New in Isabelle98 (January 1998)
   653 --------------------------------
   654 
   655 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   656 
   657 * changed lexical syntax of terms / types: dots made part of long
   658 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   659 
   660 * simpset (and claset) reference variable replaced by functions
   661 simpset / simpset_ref;
   662 
   663 * no longer supports theory aliases (via merge) and non-trivial
   664 implicit merge of thms' signatures;
   665 
   666 * most internal names of constants changed due to qualified names;
   667 
   668 * changed Pure/Sequence interface (see Pure/seq.ML);
   669 
   670 
   671 *** General Changes ***
   672 
   673 * hierachically structured name spaces (for consts, types, axms, thms
   674 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   675 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   676 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   677 long_names for fully qualified output names; NOTE: ML programs
   678 (special tactics, packages etc.) referring to internal names may have
   679 to be adapted to cope with fully qualified names; in case of severe
   680 backward campatibility problems try setting 'global_names' at compile
   681 time to have enrything declared within a flat name space; one may also
   682 fine tune name declarations in theories via the 'global' and 'local'
   683 section;
   684 
   685 * reimplemented the implicit simpset and claset using the new anytype
   686 data filed in signatures; references simpset:simpset ref etc. are
   687 replaced by functions simpset:unit->simpset and
   688 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   689 to patch your ML files accordingly;
   690 
   691 * HTML output now includes theory graph data for display with Java
   692 applet or isatool browser; data generated automatically via isatool
   693 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   694 
   695 * defs may now be conditional; improved rewrite_goals_tac to handle
   696 conditional equations;
   697 
   698 * defs now admits additional type arguments, using TYPE('a) syntax;
   699 
   700 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   701 creates a new theory node; implicit merge of thms' signatures is
   702 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   703 transfer:theory->thm->thm in (rare) cases;
   704 
   705 * improved handling of draft signatures / theories; draft thms (and
   706 ctyps, cterms) are automatically promoted to real ones;
   707 
   708 * slightly changed interfaces for oracles: admit many per theory, named
   709 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   710 
   711 * print_goals: optional output of const types (set show_consts and
   712 show_types);
   713 
   714 * improved output of warnings (###) and errors (***);
   715 
   716 * subgoal_tac displays a warning if the new subgoal has type variables;
   717 
   718 * removed old README and Makefiles;
   719 
   720 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   721 
   722 * removed obsolete init_pps and init_database;
   723 
   724 * deleted the obsolete tactical STATE, which was declared by
   725     fun STATE tacfun st = tacfun st st;
   726 
   727 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   728 (which abbreviates $HOME);
   729 
   730 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   731 use isatool fixseq to adapt your ML programs (this works for fully
   732 qualified references to the Sequence structure only!);
   733 
   734 * use_thy no longer requires writable current directory; it always
   735 reloads .ML *and* .thy file, if either one is out of date;
   736 
   737 
   738 *** Classical Reasoner ***
   739 
   740 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   741 tactics that use classical reasoning to simplify a subgoal without
   742 splitting it into several subgoals;
   743 
   744 * Safe_tac: like safe_tac but uses the default claset;
   745 
   746 
   747 *** Simplifier ***
   748 
   749 * added simplification meta rules:
   750     (asm_)(full_)simplify: simpset -> thm -> thm;
   751 
   752 * simplifier.ML no longer part of Pure -- has to be loaded by object
   753 logics (again);
   754 
   755 * added prems argument to simplification procedures;
   756 
   757 * HOL, FOL, ZF: added infix function `addsplits':
   758   instead of `<simpset> setloop (split_tac <thms>)'
   759   you can simply write `<simpset> addsplits <thms>'
   760 
   761 
   762 *** Syntax ***
   763 
   764 * TYPE('a) syntax for type reflection terms;
   765 
   766 * no longer handles consts with name "" -- declare as 'syntax' instead;
   767 
   768 * pretty printer: changed order of mixfix annotation preference (again!);
   769 
   770 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   771 
   772 
   773 *** HOL ***
   774 
   775 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   776   with `addloop' of the simplifier to faciliate case splitting in premises.
   777 
   778 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   779 
   780 * HOL/Auth: new protocol proofs including some for the Internet
   781   protocol TLS;
   782 
   783 * HOL/Map: new theory of `maps' a la VDM;
   784 
   785 * HOL/simplifier: simplification procedures nat_cancel_sums for
   786 cancelling out common nat summands from =, <, <= (in)equalities, or
   787 differences; simplification procedures nat_cancel_factor for
   788 cancelling common factor from =, <, <= (in)equalities over natural
   789 sums; nat_cancel contains both kinds of procedures, it is installed by
   790 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   791 
   792 * HOL/simplifier: terms of the form
   793   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   794   are rewritten to
   795   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   796   and those of the form
   797   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   798   are rewritten to
   799   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   800 
   801 * HOL/datatype
   802   Each datatype `t' now comes with a theorem `split_t_case' of the form
   803 
   804   P(t_case f1 ... fn x) =
   805      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   806         ...
   807        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   808      )
   809 
   810   and a theorem `split_t_case_asm' of the form
   811 
   812   P(t_case f1 ... fn x) =
   813     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   814         ...
   815        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   816      )
   817   which can be added to a simpset via `addsplits'. The existing theorems
   818   expand_list_case and expand_option_case have been renamed to
   819   split_list_case and split_option_case.
   820 
   821 * HOL/Arithmetic:
   822   - `pred n' is automatically converted to `n-1'.
   823     Users are strongly encouraged not to use `pred' any longer,
   824     because it will disappear altogether at some point.
   825   - Users are strongly encouraged to write "0 < n" rather than
   826     "n ~= 0". Theorems and proof tools have been modified towards this
   827     `standard'.
   828 
   829 * HOL/Lists:
   830   the function "set_of_list" has been renamed "set" (and its theorems too);
   831   the function "nth" now takes its arguments in the reverse order and
   832   has acquired the infix notation "!" as in "xs!n".
   833 
   834 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   835 
   836 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   837   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   838 
   839 * HOL/record: extensible records with schematic structural subtyping
   840 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   841 still lacks various theorems and concrete record syntax;
   842 
   843 
   844 *** HOLCF ***
   845 
   846 * removed "axioms" and "generated by" sections;
   847 
   848 * replaced "ops" section by extended "consts" section, which is capable of
   849   handling the continuous function space "->" directly;
   850 
   851 * domain package:
   852   . proves theorems immediately and stores them in the theory,
   853   . creates hierachical name space,
   854   . now uses normal mixfix annotations (instead of cinfix...),
   855   . minor changes to some names and values (for consistency),
   856   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   857   . separator between mutual domain defs: changed "," to "and",
   858   . improved handling of sort constraints;  now they have to
   859     appear on the left-hand side of the equations only;
   860 
   861 * fixed LAM <x,y,zs>.b syntax;
   862 
   863 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   864 adm (%x. P (t x)), where P is chainfinite and t continuous;
   865 
   866 
   867 *** FOL and ZF ***
   868 
   869 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   870   with `addloop' of the simplifier to faciliate case splitting in premises.
   871 
   872 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   873 in HOL, they strip ALL and --> from proved theorems;
   874 
   875 
   876 
   877 New in Isabelle94-8 (May 1997)
   878 ------------------------------
   879 
   880 *** General Changes ***
   881 
   882 * new utilities to build / run / maintain Isabelle etc. (in parts
   883 still somewhat experimental); old Makefiles etc. still functional;
   884 
   885 * new 'Isabelle System Manual';
   886 
   887 * INSTALL text, together with ./configure and ./build scripts;
   888 
   889 * reimplemented type inference for greater efficiency, better error
   890 messages and clean internal interface;
   891 
   892 * prlim command for dealing with lots of subgoals (an easier way of
   893 setting goals_limit);
   894 
   895 
   896 *** Syntax ***
   897 
   898 * supports alternative (named) syntax tables (parser and pretty
   899 printer); internal interface is provided by add_modesyntax(_i);
   900 
   901 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   902 be used in conjunction with the Isabelle symbol font; uses the
   903 "symbols" syntax table;
   904 
   905 * added token_translation interface (may translate name tokens in
   906 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   907 the current print_mode); IMPORTANT: user print translation functions
   908 are responsible for marking newly introduced bounds
   909 (Syntax.mark_boundT);
   910 
   911 * token translations for modes "xterm" and "xterm_color" that display
   912 names in bold, underline etc. or colors (which requires a color
   913 version of xterm);
   914 
   915 * infixes may now be declared with names independent of their syntax;
   916 
   917 * added typed_print_translation (like print_translation, but may
   918 access type of constant);
   919 
   920 
   921 *** Classical Reasoner ***
   922 
   923 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   924 some limitations.  Blast_tac...
   925   + ignores addss, addbefore, addafter; this restriction is intrinsic
   926   + ignores elimination rules that don't have the correct format
   927         (the conclusion MUST be a formula variable)
   928   + ignores types, which can make HOL proofs fail
   929   + rules must not require higher-order unification, e.g. apply_type in ZF
   930     [message "Function Var's argument not a bound variable" relates to this]
   931   + its proof strategy is more general but can actually be slower
   932 
   933 * substitution with equality assumptions no longer permutes other
   934 assumptions;
   935 
   936 * minor changes in semantics of addafter (now called addaltern); renamed
   937 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   938 (and access functions for it);
   939 
   940 * improved combination of classical reasoner and simplifier:
   941   + functions for handling clasimpsets
   942   + improvement of addss: now the simplifier is called _after_ the
   943     safe steps.
   944   + safe variant of addss called addSss: uses safe simplifications
   945     _during_ the safe steps. It is more complete as it allows multiple
   946     instantiations of unknowns (e.g. with slow_tac).
   947 
   948 *** Simplifier ***
   949 
   950 * added interface for simplification procedures (functions that
   951 produce *proven* rewrite rules on the fly, depending on current
   952 redex);
   953 
   954 * ordering on terms as parameter (used for ordered rewriting);
   955 
   956 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   957 
   958 * the solver is now split into a safe and an unsafe part.
   959 This should be invisible for the normal user, except that the
   960 functions setsolver and addsolver have been renamed to setSolver and
   961 addSolver; added safe_asm_full_simp_tac;
   962 
   963 
   964 *** HOL ***
   965 
   966 * a generic induction tactic `induct_tac' which works for all datatypes and
   967 also for type `nat';
   968 
   969 * a generic case distinction tactic `exhaust_tac' which works for all
   970 datatypes and also for type `nat';
   971 
   972 * each datatype comes with a function `size';
   973 
   974 * patterns in case expressions allow tuple patterns as arguments to
   975 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   976 
   977 * primrec now also works with type nat;
   978 
   979 * recdef: a new declaration form, allows general recursive functions to be
   980 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   981 
   982 * the constant for negation has been renamed from "not" to "Not" to
   983 harmonize with FOL, ZF, LK, etc.;
   984 
   985 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   986 infinite lists;
   987 
   988 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   989 
   990 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   991 problems in commutative rings, using axiomatic type classes for + and *;
   992 
   993 * more examples in HOL/MiniML and HOL/Auth;
   994 
   995 * more default rewrite rules for quantifiers, union/intersection;
   996 
   997 * a new constant `arbitrary == @x.False';
   998 
   999 * HOLCF/IOA replaces old HOL/IOA;
  1000 
  1001 * HOLCF changes: derived all rules and arities
  1002   + axiomatic type classes instead of classes
  1003   + typedef instead of faking type definitions
  1004   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1005   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1006   + eliminated the types void, one, tr
  1007   + use unit lift and bool lift (with translations) instead of one and tr
  1008   + eliminated blift from Lift3.thy (use Def instead of blift)
  1009   all eliminated rules are derived as theorems --> no visible changes ;
  1010 
  1011 
  1012 *** ZF ***
  1013 
  1014 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1015 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1016 as ZF_cs addSIs [equalityI];
  1017 
  1018 
  1019 
  1020 New in Isabelle94-7 (November 96)
  1021 ---------------------------------
  1022 
  1023 * allowing negative levels (as offsets) in prlev and choplev;
  1024 
  1025 * super-linear speedup for large simplifications;
  1026 
  1027 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1028 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1029 FAIL); can suppress it using the command Delsimps (ex_simps @
  1030 all_simps); De Morgan laws are also now included, by default;
  1031 
  1032 * improved printing of ==>  :  ~:
  1033 
  1034 * new object-logic "Sequents" adds linear logic, while replacing LK
  1035 and Modal (thanks to Sara Kalvala);
  1036 
  1037 * HOL/Auth: correctness proofs for authentication protocols;
  1038 
  1039 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1040 examples on HOL/Auth);
  1041 
  1042 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1043 the rewriter and classical reasoner simultaneously;
  1044 
  1045 * function uresult no longer returns theorems in "standard" format;
  1046 regain previous version by: val uresult = standard o uresult;
  1047 
  1048 
  1049 
  1050 New in Isabelle94-6
  1051 -------------------
  1052 
  1053 * oracles -- these establish an interface between Isabelle and trusted
  1054 external reasoners, which may deliver results as theorems;
  1055 
  1056 * proof objects (in particular record all uses of oracles);
  1057 
  1058 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1059 
  1060 * "constdefs" section in theory files;
  1061 
  1062 * "primrec" section (HOL) no longer requires names;
  1063 
  1064 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1065 
  1066 
  1067 
  1068 New in Isabelle94-5
  1069 -------------------
  1070 
  1071 * reduced space requirements;
  1072 
  1073 * automatic HTML generation from theories;
  1074 
  1075 * theory files no longer require "..." (quotes) around most types;
  1076 
  1077 * new examples, including two proofs of the Church-Rosser theorem;
  1078 
  1079 * non-curried (1994) version of HOL is no longer distributed;
  1080 
  1081 
  1082 
  1083 New in Isabelle94-4
  1084 -------------------
  1085 
  1086 * greatly reduced space requirements;
  1087 
  1088 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1089 
  1090 * searchable theorem database (see the section "Retrieving theorems" on
  1091 page 8 of the Reference Manual);
  1092 
  1093 * new examples, including Grabczewski's monumental case study of the
  1094 Axiom of Choice;
  1095 
  1096 * The previous version of HOL renamed to Old_HOL;
  1097 
  1098 * The new version of HOL (previously called CHOL) uses a curried syntax
  1099 for functions.  Application looks like f a b instead of f(a,b);
  1100 
  1101 * Mutually recursive inductive definitions finally work in HOL;
  1102 
  1103 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1104 translates to the operator "split";
  1105 
  1106 
  1107 
  1108 New in Isabelle94-3
  1109 -------------------
  1110 
  1111 * new infix operator, addss, allowing the classical reasoner to
  1112 perform simplification at each step of its search.  Example:
  1113         fast_tac (cs addss ss)
  1114 
  1115 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1116 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1117 look like (a,b) instead of <a,b>;
  1118 
  1119 * PLEASE NOTE: CHOL will eventually replace HOL!
  1120 
  1121 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1122 It translates to the operator "split".  A new theory of integers is available;
  1123 
  1124 * In ZF, integer numerals now denote two's-complement binary integers.
  1125 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1126 
  1127 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1128 of the Axiom of Choice;
  1129 
  1130 
  1131 
  1132 New in Isabelle94-2
  1133 -------------------
  1134 
  1135 * Significantly faster resolution;
  1136 
  1137 * the different sections in a .thy file can now be mixed and repeated
  1138 freely;
  1139 
  1140 * Database of theorems for FOL, HOL and ZF.  New
  1141 commands including qed, qed_goal and bind_thm store theorems in the database.
  1142 
  1143 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1144 a given theory (thms_of), or find out what theory a theorem was proved in
  1145 (theory_of_thm);
  1146 
  1147 * Bugs fixed in the inductive definition and datatype packages;
  1148 
  1149 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1150 and HOL_dup_cs obsolete;
  1151 
  1152 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1153 have been removed;
  1154 
  1155 * Simpler definition of function space in ZF;
  1156 
  1157 * new results about cardinal and ordinal arithmetic in ZF;
  1158 
  1159 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1160 types;
  1161 
  1162 
  1163 $Id$