NEWS
author wenzelm
Wed Sep 01 21:20:04 1999 +0200 (1999-09-01)
changeset 7420 cba45c114f3b
parent 7327 596318fdb379
child 7444 ee17ad649c26
permissions -rw-r--r--
structures Vartab / Termtab (instances of TableFun);
     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 * structures Vartab / Termtab (instances of TableFun) offer efficient
   246 tables indexed by indexname_ord / term_ord (compatible with aconv);
   247 
   248 * AxClass.axclass_tac lost the theory argument;
   249 
   250 * tuned current_goals_markers semantics: begin / end goal avoids
   251 printing empty lines;
   252 
   253 * removed prs and prs_fn hook, which was broken because it did not
   254 include \n in its semantics, forcing writeln to add one
   255 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   256 string -> unit if you really want to output text without newline;
   257 
   258 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   259 plain output, interface builders may have to enable 'isabelle_font'
   260 mode to get Isabelle font glyphs as before;
   261 
   262 * refined token_translation interface; INCOMPATIBILITY: output length
   263 now of type real instead of int;
   264 
   265 * theory loader actions may be traced via new ThyInfo.add_hook
   266 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   267 your own database of information attached to *whole* theories -- as
   268 opposed to intra-theory data slots offered via TheoryDataFun;
   269 
   270 
   271 
   272 New in Isabelle98-1 (October 1998)
   273 ----------------------------------
   274 
   275 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   276 
   277 * several changes of automated proof tools;
   278 
   279 * HOL: major changes to the inductive and datatype packages, including
   280 some minor incompatibilities of theory syntax;
   281 
   282 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   283 called `inj_on';
   284 
   285 * HOL: removed duplicate thms in Arith:
   286   less_imp_add_less  should be replaced by  trans_less_add1
   287   le_imp_add_le      should be replaced by  trans_le_add1
   288 
   289 * HOL: unary minus is now overloaded (new type constraints may be
   290 required);
   291 
   292 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   293 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   294 now taken as an integer constant.
   295 
   296 * Pure: ML function 'theory_of' renamed to 'theory';
   297 
   298 
   299 *** Proof tools ***
   300 
   301 * Simplifier:
   302   1. Asm_full_simp_tac is now more aggressive.
   303      1. It will sometimes reorient premises if that increases their power to
   304         simplify.
   305      2. It does no longer proceed strictly from left to right but may also
   306         rotate premises to achieve further simplification.
   307      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   308      old Asm_full_simp_tac in that it does not rotate premises.
   309   2. The simplifier now knows a little bit about nat-arithmetic.
   310 
   311 * Classical reasoner: wrapper mechanism for the classical reasoner now
   312 allows for selected deletion of wrappers, by introduction of names for
   313 wrapper functionals.  This implies that addbefore, addSbefore,
   314 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   315 and that adding two tactics with the same name overwrites the first
   316 one (emitting a warning).
   317   type wrapper = (int -> tactic) -> (int -> tactic)
   318   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   319   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   320   delWrapper, delSWrapper: claset *  string            -> claset
   321   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   322 
   323 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   324 semantics; addbefore now affects only the unsafe part of step_tac
   325 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   326 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   327 by Force_tac;
   328 
   329 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   330 compWrapper; added safe wrapper (and access functions for it);
   331 
   332 * HOL/split_all_tac is now much faster and fails if there is nothing
   333 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   334 and the names of the automatically generated variables have changed.
   335 split_all_tac has moved within claset() from unsafe wrappers to safe
   336 wrappers, which means that !!-bound variables are split much more
   337 aggressively, and safe_tac and clarify_tac now split such variables.
   338 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   339 Note: the same holds for record_split_tac, which does the job of
   340 split_all_tac for record fields.
   341 
   342 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   343 permanently to the default simpset using Addsplits just like
   344 Addsimps. They can be removed via Delsplits just like
   345 Delsimps. Lower-case versions are also available.
   346 
   347 * HOL/Simplifier: The rule split_if is now part of the default
   348 simpset. This means that the simplifier will eliminate all occurrences
   349 of if-then-else in the conclusion of a goal. To prevent this, you can
   350 either remove split_if completely from the default simpset by
   351 `Delsplits [split_if]' or remove it in a specific call of the
   352 simplifier using `... delsplits [split_if]'.  You can also add/delete
   353 other case splitting rules to/from the default simpset: every datatype
   354 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   355 t is the name of the datatype).
   356 
   357 * Classical reasoner / Simplifier combination: new force_tac (and
   358 derivatives Force_tac, force) combines rewriting and classical
   359 reasoning (and whatever other tools) similarly to auto_tac, but is
   360 aimed to solve the given subgoal completely.
   361 
   362 
   363 *** General ***
   364 
   365 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   366 and `goalw': the theory is no longer needed as an explicit argument -
   367 the current theory context is used; assumptions are no longer returned
   368 at the ML-level unless one of them starts with ==> or !!; it is
   369 recommended to convert to these new commands using isatool fixgoal
   370 (backup your sources first!);
   371 
   372 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   373 the current theory context, and 'theory' to lookup stored theories;
   374 
   375 * new theory section 'locale' for declaring constants, assumptions and
   376 definitions that have local scope;
   377 
   378 * new theory section 'nonterminals' for purely syntactic types;
   379 
   380 * new theory section 'setup' for generic ML setup functions
   381 (e.g. package initialization);
   382 
   383 * the distribution now includes Isabelle icons: see
   384 lib/logo/isabelle-{small,tiny}.xpm;
   385 
   386 * isatool install - install binaries with absolute references to
   387 ISABELLE_HOME/bin;
   388 
   389 * isatool logo -- create instances of the Isabelle logo (as EPS);
   390 
   391 * print mode 'emacs' reserved for Isamode;
   392 
   393 * support multiple print (ast) translations per constant name;
   394 
   395 * theorems involving oracles are now printed with a suffixed [!];
   396 
   397 
   398 *** HOL ***
   399 
   400 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   401 
   402 * HOL/inductive package reorganized and improved: now supports mutual
   403 definitions such as
   404 
   405   inductive EVEN ODD
   406     intrs
   407       null "0 : EVEN"
   408       oddI "n : EVEN ==> Suc n : ODD"
   409       evenI "n : ODD ==> Suc n : EVEN"
   410 
   411 new theorem list "elims" contains an elimination rule for each of the
   412 recursive sets; inductive definitions now handle disjunctive premises
   413 correctly (also ZF);
   414 
   415 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   416 "mutual_induct" no longer exists - the induction rule is always
   417 contained in "induct";
   418 
   419 
   420 * HOL/datatype package re-implemented and greatly improved: now
   421 supports mutually recursive datatypes such as
   422 
   423   datatype
   424     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   425             | SUM ('a aexp) ('a aexp)
   426             | DIFF ('a aexp) ('a aexp)
   427             | NUM 'a
   428   and
   429     'a bexp = LESS ('a aexp) ('a aexp)
   430             | AND ('a bexp) ('a bexp)
   431             | OR ('a bexp) ('a bexp)
   432 
   433 as well as indirectly recursive datatypes such as
   434 
   435   datatype
   436     ('a, 'b) term = Var 'a
   437                   | App 'b ((('a, 'b) term) list)
   438 
   439 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   440 induction on mutually / indirectly recursive datatypes.
   441 
   442 Primrec equations are now stored in theory and can be accessed via
   443 <function_name>.simps.
   444 
   445 INCOMPATIBILITIES:
   446 
   447   - Theories using datatypes must now have theory Datatype as an
   448     ancestor.
   449   - The specific <typename>.induct_tac no longer exists - use the
   450     generic induct_tac instead.
   451   - natE has been renamed to nat.exhaust - use exhaust_tac
   452     instead of res_inst_tac ... natE. Note that the variable
   453     names in nat.exhaust differ from the names in natE, this
   454     may cause some "fragile" proofs to fail.
   455   - The theorems split_<typename>_case and split_<typename>_case_asm
   456     have been renamed to <typename>.split and <typename>.split_asm.
   457   - Since default sorts of type variables are now handled correctly,
   458     some datatype definitions may have to be annotated with explicit
   459     sort constraints.
   460   - Primrec definitions no longer require function name and type
   461     of recursive argument.
   462 
   463 Consider using isatool fixdatatype to adapt your theories and proof
   464 scripts to the new package (backup your sources first!).
   465 
   466 
   467 * HOL/record package: considerably improved implementation; now
   468 includes concrete syntax for record types, terms, updates; theorems
   469 for surjective pairing and splitting !!-bound record variables; proof
   470 support is as follows:
   471 
   472   1) standard conversions (selectors or updates applied to record
   473 constructor terms) are part of the standard simpset;
   474 
   475   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   476 made part of standard simpset and claset via addIffs;
   477 
   478   3) a tactic for record field splitting (record_split_tac) is part of
   479 the standard claset (addSWrapper);
   480 
   481 To get a better idea about these rules you may retrieve them via
   482 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   483 the name of your record type.
   484 
   485 The split tactic 3) conceptually simplifies by the following rule:
   486 
   487   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   488 
   489 Thus any record variable that is bound by meta-all will automatically
   490 blow up into some record constructor term, consequently the
   491 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   492 solve record problems automatically.
   493 
   494 
   495 * reorganized the main HOL image: HOL/Integ and String loaded by
   496 default; theory Main includes everything;
   497 
   498 * automatic simplification of integer sums and comparisons, using cancellation;
   499 
   500 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   501 
   502 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   503 
   504 * many new identities for unions, intersections, set difference, etc.;
   505 
   506 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   507 called split_if, split_split, split_sum_case and split_nat_case (to go
   508 with add/delsplits);
   509 
   510 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   511 (?x::unit) = (); this is made part of the default simpset, which COULD
   512 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   513 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   514 unit_abs_eta_conv is added in order to counter the effect of
   515 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   516 %u.f();
   517 
   518 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   519 makes more sense);
   520 
   521 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   522   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   523   disjointness reasoning but breaking a few old proofs.
   524 
   525 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   526 to 'converse' from 'inverse' (for compatibility with ZF and some
   527 literature);
   528 
   529 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   530 the well-founded relation;
   531 
   532 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   533     Compl A.  The "Compl" syntax remains available as input syntax for this
   534     release ONLY.
   535 
   536 * HOL/Update: new theory of function updates:
   537     f(a:=b) == %x. if x=a then b else f x
   538 may also be iterated as in f(a:=b,c:=d,...);
   539 
   540 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   541 
   542 * HOL/List:
   543   - new function list_update written xs[i:=v] that updates the i-th
   544     list position. May also be iterated as in xs[i:=a,j:=b,...].
   545   - new function `upt' written [i..j(] which generates the list
   546     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   547     bound write [i..j], which is a shorthand for [i..j+1(].
   548   - new lexicographic orderings and corresponding wellfoundedness theorems.
   549 
   550 * HOL/Arith:
   551   - removed 'pred' (predecessor) function;
   552   - generalized some theorems about n-1;
   553   - many new laws about "div" and "mod";
   554   - new laws about greatest common divisors (see theory ex/Primes);
   555 
   556 * HOL/Relation: renamed the relational operator r^-1 "converse"
   557 instead of "inverse";
   558 
   559 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   560   of the multiset ordering;
   561 
   562 * directory HOL/Real: a construction of the reals using Dedekind cuts
   563   (not included by default);
   564 
   565 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   566 
   567 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   568   programs, i.e. different program variables may have different types.
   569 
   570 * calling (stac rew i) now fails if "rew" has no effect on the goal
   571   [previously, this check worked only if the rewrite rule was unconditional]
   572   Now rew can involve either definitions or equalities (either == or =).
   573 
   574 
   575 *** ZF ***
   576 
   577 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   578   only the theorems proved on ZF.ML;
   579 
   580 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   581   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   582   disjointness reasoning but breaking a few old proofs.
   583 
   584 * ZF/Update: new theory of function updates
   585     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   586   may also be iterated as in f(a:=b,c:=d,...);
   587 
   588 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   589 
   590 * calling (stac rew i) now fails if "rew" has no effect on the goal
   591   [previously, this check worked only if the rewrite rule was unconditional]
   592   Now rew can involve either definitions or equalities (either == or =).
   593 
   594 * case_tac provided for compatibility with HOL
   595     (like the old excluded_middle_tac, but with subgoals swapped)
   596 
   597 
   598 *** Internal programming interfaces ***
   599 
   600 * Pure: several new basic modules made available for general use, see
   601 also src/Pure/README;
   602 
   603 * improved the theory data mechanism to support encapsulation (data
   604 kind name replaced by private Object.kind, acting as authorization
   605 key); new type-safe user interface via functor TheoryDataFun; generic
   606 print_data function becomes basically useless;
   607 
   608 * removed global_names compatibility flag -- all theory declarations
   609 are qualified by default;
   610 
   611 * module Pure/Syntax now offers quote / antiquote translation
   612 functions (useful for Hoare logic etc. with implicit dependencies);
   613 see HOL/ex/Antiquote for an example use;
   614 
   615 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   616 cterm -> thm;
   617 
   618 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   619 subgoal;
   620 
   621 * Display.print_goals function moved to Locale.print_goals;
   622 
   623 * standard print function for goals supports current_goals_markers
   624 variable for marking begin of proof, end of proof, start of goal; the
   625 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   626 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   627 for example;
   628 
   629 
   630 
   631 New in Isabelle98 (January 1998)
   632 --------------------------------
   633 
   634 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   635 
   636 * changed lexical syntax of terms / types: dots made part of long
   637 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   638 
   639 * simpset (and claset) reference variable replaced by functions
   640 simpset / simpset_ref;
   641 
   642 * no longer supports theory aliases (via merge) and non-trivial
   643 implicit merge of thms' signatures;
   644 
   645 * most internal names of constants changed due to qualified names;
   646 
   647 * changed Pure/Sequence interface (see Pure/seq.ML);
   648 
   649 
   650 *** General Changes ***
   651 
   652 * hierachically structured name spaces (for consts, types, axms, thms
   653 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   654 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   655 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   656 long_names for fully qualified output names; NOTE: ML programs
   657 (special tactics, packages etc.) referring to internal names may have
   658 to be adapted to cope with fully qualified names; in case of severe
   659 backward campatibility problems try setting 'global_names' at compile
   660 time to have enrything declared within a flat name space; one may also
   661 fine tune name declarations in theories via the 'global' and 'local'
   662 section;
   663 
   664 * reimplemented the implicit simpset and claset using the new anytype
   665 data filed in signatures; references simpset:simpset ref etc. are
   666 replaced by functions simpset:unit->simpset and
   667 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   668 to patch your ML files accordingly;
   669 
   670 * HTML output now includes theory graph data for display with Java
   671 applet or isatool browser; data generated automatically via isatool
   672 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   673 
   674 * defs may now be conditional; improved rewrite_goals_tac to handle
   675 conditional equations;
   676 
   677 * defs now admits additional type arguments, using TYPE('a) syntax;
   678 
   679 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   680 creates a new theory node; implicit merge of thms' signatures is
   681 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   682 transfer:theory->thm->thm in (rare) cases;
   683 
   684 * improved handling of draft signatures / theories; draft thms (and
   685 ctyps, cterms) are automatically promoted to real ones;
   686 
   687 * slightly changed interfaces for oracles: admit many per theory, named
   688 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   689 
   690 * print_goals: optional output of const types (set show_consts and
   691 show_types);
   692 
   693 * improved output of warnings (###) and errors (***);
   694 
   695 * subgoal_tac displays a warning if the new subgoal has type variables;
   696 
   697 * removed old README and Makefiles;
   698 
   699 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   700 
   701 * removed obsolete init_pps and init_database;
   702 
   703 * deleted the obsolete tactical STATE, which was declared by
   704     fun STATE tacfun st = tacfun st st;
   705 
   706 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   707 (which abbreviates $HOME);
   708 
   709 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   710 use isatool fixseq to adapt your ML programs (this works for fully
   711 qualified references to the Sequence structure only!);
   712 
   713 * use_thy no longer requires writable current directory; it always
   714 reloads .ML *and* .thy file, if either one is out of date;
   715 
   716 
   717 *** Classical Reasoner ***
   718 
   719 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   720 tactics that use classical reasoning to simplify a subgoal without
   721 splitting it into several subgoals;
   722 
   723 * Safe_tac: like safe_tac but uses the default claset;
   724 
   725 
   726 *** Simplifier ***
   727 
   728 * added simplification meta rules:
   729     (asm_)(full_)simplify: simpset -> thm -> thm;
   730 
   731 * simplifier.ML no longer part of Pure -- has to be loaded by object
   732 logics (again);
   733 
   734 * added prems argument to simplification procedures;
   735 
   736 * HOL, FOL, ZF: added infix function `addsplits':
   737   instead of `<simpset> setloop (split_tac <thms>)'
   738   you can simply write `<simpset> addsplits <thms>'
   739 
   740 
   741 *** Syntax ***
   742 
   743 * TYPE('a) syntax for type reflection terms;
   744 
   745 * no longer handles consts with name "" -- declare as 'syntax' instead;
   746 
   747 * pretty printer: changed order of mixfix annotation preference (again!);
   748 
   749 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   750 
   751 
   752 *** HOL ***
   753 
   754 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   755   with `addloop' of the simplifier to faciliate case splitting in premises.
   756 
   757 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   758 
   759 * HOL/Auth: new protocol proofs including some for the Internet
   760   protocol TLS;
   761 
   762 * HOL/Map: new theory of `maps' a la VDM;
   763 
   764 * HOL/simplifier: simplification procedures nat_cancel_sums for
   765 cancelling out common nat summands from =, <, <= (in)equalities, or
   766 differences; simplification procedures nat_cancel_factor for
   767 cancelling common factor from =, <, <= (in)equalities over natural
   768 sums; nat_cancel contains both kinds of procedures, it is installed by
   769 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   770 
   771 * HOL/simplifier: terms of the form
   772   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   773   are rewritten to
   774   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   775   and those of the form
   776   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   777   are rewritten to
   778   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   779 
   780 * HOL/datatype
   781   Each datatype `t' now comes with a theorem `split_t_case' of the form
   782 
   783   P(t_case f1 ... fn x) =
   784      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   785         ...
   786        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   787      )
   788 
   789   and a theorem `split_t_case_asm' of the form
   790 
   791   P(t_case f1 ... fn x) =
   792     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   793         ...
   794        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   795      )
   796   which can be added to a simpset via `addsplits'. The existing theorems
   797   expand_list_case and expand_option_case have been renamed to
   798   split_list_case and split_option_case.
   799 
   800 * HOL/Arithmetic:
   801   - `pred n' is automatically converted to `n-1'.
   802     Users are strongly encouraged not to use `pred' any longer,
   803     because it will disappear altogether at some point.
   804   - Users are strongly encouraged to write "0 < n" rather than
   805     "n ~= 0". Theorems and proof tools have been modified towards this
   806     `standard'.
   807 
   808 * HOL/Lists:
   809   the function "set_of_list" has been renamed "set" (and its theorems too);
   810   the function "nth" now takes its arguments in the reverse order and
   811   has acquired the infix notation "!" as in "xs!n".
   812 
   813 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   814 
   815 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   816   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   817 
   818 * HOL/record: extensible records with schematic structural subtyping
   819 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   820 still lacks various theorems and concrete record syntax;
   821 
   822 
   823 *** HOLCF ***
   824 
   825 * removed "axioms" and "generated by" sections;
   826 
   827 * replaced "ops" section by extended "consts" section, which is capable of
   828   handling the continuous function space "->" directly;
   829 
   830 * domain package:
   831   . proves theorems immediately and stores them in the theory,
   832   . creates hierachical name space,
   833   . now uses normal mixfix annotations (instead of cinfix...),
   834   . minor changes to some names and values (for consistency),
   835   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   836   . separator between mutual domain defs: changed "," to "and",
   837   . improved handling of sort constraints;  now they have to
   838     appear on the left-hand side of the equations only;
   839 
   840 * fixed LAM <x,y,zs>.b syntax;
   841 
   842 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   843 adm (%x. P (t x)), where P is chainfinite and t continuous;
   844 
   845 
   846 *** FOL and ZF ***
   847 
   848 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   849   with `addloop' of the simplifier to faciliate case splitting in premises.
   850 
   851 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   852 in HOL, they strip ALL and --> from proved theorems;
   853 
   854 
   855 
   856 New in Isabelle94-8 (May 1997)
   857 ------------------------------
   858 
   859 *** General Changes ***
   860 
   861 * new utilities to build / run / maintain Isabelle etc. (in parts
   862 still somewhat experimental); old Makefiles etc. still functional;
   863 
   864 * new 'Isabelle System Manual';
   865 
   866 * INSTALL text, together with ./configure and ./build scripts;
   867 
   868 * reimplemented type inference for greater efficiency, better error
   869 messages and clean internal interface;
   870 
   871 * prlim command for dealing with lots of subgoals (an easier way of
   872 setting goals_limit);
   873 
   874 
   875 *** Syntax ***
   876 
   877 * supports alternative (named) syntax tables (parser and pretty
   878 printer); internal interface is provided by add_modesyntax(_i);
   879 
   880 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   881 be used in conjunction with the Isabelle symbol font; uses the
   882 "symbols" syntax table;
   883 
   884 * added token_translation interface (may translate name tokens in
   885 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   886 the current print_mode); IMPORTANT: user print translation functions
   887 are responsible for marking newly introduced bounds
   888 (Syntax.mark_boundT);
   889 
   890 * token translations for modes "xterm" and "xterm_color" that display
   891 names in bold, underline etc. or colors (which requires a color
   892 version of xterm);
   893 
   894 * infixes may now be declared with names independent of their syntax;
   895 
   896 * added typed_print_translation (like print_translation, but may
   897 access type of constant);
   898 
   899 
   900 *** Classical Reasoner ***
   901 
   902 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   903 some limitations.  Blast_tac...
   904   + ignores addss, addbefore, addafter; this restriction is intrinsic
   905   + ignores elimination rules that don't have the correct format
   906         (the conclusion MUST be a formula variable)
   907   + ignores types, which can make HOL proofs fail
   908   + rules must not require higher-order unification, e.g. apply_type in ZF
   909     [message "Function Var's argument not a bound variable" relates to this]
   910   + its proof strategy is more general but can actually be slower
   911 
   912 * substitution with equality assumptions no longer permutes other
   913 assumptions;
   914 
   915 * minor changes in semantics of addafter (now called addaltern); renamed
   916 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   917 (and access functions for it);
   918 
   919 * improved combination of classical reasoner and simplifier:
   920   + functions for handling clasimpsets
   921   + improvement of addss: now the simplifier is called _after_ the
   922     safe steps.
   923   + safe variant of addss called addSss: uses safe simplifications
   924     _during_ the safe steps. It is more complete as it allows multiple
   925     instantiations of unknowns (e.g. with slow_tac).
   926 
   927 *** Simplifier ***
   928 
   929 * added interface for simplification procedures (functions that
   930 produce *proven* rewrite rules on the fly, depending on current
   931 redex);
   932 
   933 * ordering on terms as parameter (used for ordered rewriting);
   934 
   935 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   936 
   937 * the solver is now split into a safe and an unsafe part.
   938 This should be invisible for the normal user, except that the
   939 functions setsolver and addsolver have been renamed to setSolver and
   940 addSolver; added safe_asm_full_simp_tac;
   941 
   942 
   943 *** HOL ***
   944 
   945 * a generic induction tactic `induct_tac' which works for all datatypes and
   946 also for type `nat';
   947 
   948 * a generic case distinction tactic `exhaust_tac' which works for all
   949 datatypes and also for type `nat';
   950 
   951 * each datatype comes with a function `size';
   952 
   953 * patterns in case expressions allow tuple patterns as arguments to
   954 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   955 
   956 * primrec now also works with type nat;
   957 
   958 * recdef: a new declaration form, allows general recursive functions to be
   959 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   960 
   961 * the constant for negation has been renamed from "not" to "Not" to
   962 harmonize with FOL, ZF, LK, etc.;
   963 
   964 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   965 infinite lists;
   966 
   967 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   968 
   969 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   970 problems in commutative rings, using axiomatic type classes for + and *;
   971 
   972 * more examples in HOL/MiniML and HOL/Auth;
   973 
   974 * more default rewrite rules for quantifiers, union/intersection;
   975 
   976 * a new constant `arbitrary == @x.False';
   977 
   978 * HOLCF/IOA replaces old HOL/IOA;
   979 
   980 * HOLCF changes: derived all rules and arities
   981   + axiomatic type classes instead of classes
   982   + typedef instead of faking type definitions
   983   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   984   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   985   + eliminated the types void, one, tr
   986   + use unit lift and bool lift (with translations) instead of one and tr
   987   + eliminated blift from Lift3.thy (use Def instead of blift)
   988   all eliminated rules are derived as theorems --> no visible changes ;
   989 
   990 
   991 *** ZF ***
   992 
   993 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   994 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   995 as ZF_cs addSIs [equalityI];
   996 
   997 
   998 
   999 New in Isabelle94-7 (November 96)
  1000 ---------------------------------
  1001 
  1002 * allowing negative levels (as offsets) in prlev and choplev;
  1003 
  1004 * super-linear speedup for large simplifications;
  1005 
  1006 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1007 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1008 FAIL); can suppress it using the command Delsimps (ex_simps @
  1009 all_simps); De Morgan laws are also now included, by default;
  1010 
  1011 * improved printing of ==>  :  ~:
  1012 
  1013 * new object-logic "Sequents" adds linear logic, while replacing LK
  1014 and Modal (thanks to Sara Kalvala);
  1015 
  1016 * HOL/Auth: correctness proofs for authentication protocols;
  1017 
  1018 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1019 examples on HOL/Auth);
  1020 
  1021 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1022 the rewriter and classical reasoner simultaneously;
  1023 
  1024 * function uresult no longer returns theorems in "standard" format;
  1025 regain previous version by: val uresult = standard o uresult;
  1026 
  1027 
  1028 
  1029 New in Isabelle94-6
  1030 -------------------
  1031 
  1032 * oracles -- these establish an interface between Isabelle and trusted
  1033 external reasoners, which may deliver results as theorems;
  1034 
  1035 * proof objects (in particular record all uses of oracles);
  1036 
  1037 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1038 
  1039 * "constdefs" section in theory files;
  1040 
  1041 * "primrec" section (HOL) no longer requires names;
  1042 
  1043 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1044 
  1045 
  1046 
  1047 New in Isabelle94-5
  1048 -------------------
  1049 
  1050 * reduced space requirements;
  1051 
  1052 * automatic HTML generation from theories;
  1053 
  1054 * theory files no longer require "..." (quotes) around most types;
  1055 
  1056 * new examples, including two proofs of the Church-Rosser theorem;
  1057 
  1058 * non-curried (1994) version of HOL is no longer distributed;
  1059 
  1060 
  1061 
  1062 New in Isabelle94-4
  1063 -------------------
  1064 
  1065 * greatly reduced space requirements;
  1066 
  1067 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1068 
  1069 * searchable theorem database (see the section "Retrieving theorems" on
  1070 page 8 of the Reference Manual);
  1071 
  1072 * new examples, including Grabczewski's monumental case study of the
  1073 Axiom of Choice;
  1074 
  1075 * The previous version of HOL renamed to Old_HOL;
  1076 
  1077 * The new version of HOL (previously called CHOL) uses a curried syntax
  1078 for functions.  Application looks like f a b instead of f(a,b);
  1079 
  1080 * Mutually recursive inductive definitions finally work in HOL;
  1081 
  1082 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1083 translates to the operator "split";
  1084 
  1085 
  1086 
  1087 New in Isabelle94-3
  1088 -------------------
  1089 
  1090 * new infix operator, addss, allowing the classical reasoner to
  1091 perform simplification at each step of its search.  Example:
  1092         fast_tac (cs addss ss)
  1093 
  1094 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1095 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1096 look like (a,b) instead of <a,b>;
  1097 
  1098 * PLEASE NOTE: CHOL will eventually replace HOL!
  1099 
  1100 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1101 It translates to the operator "split".  A new theory of integers is available;
  1102 
  1103 * In ZF, integer numerals now denote two's-complement binary integers.
  1104 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1105 
  1106 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1107 of the Axiom of Choice;
  1108 
  1109 
  1110 
  1111 New in Isabelle94-2
  1112 -------------------
  1113 
  1114 * Significantly faster resolution;
  1115 
  1116 * the different sections in a .thy file can now be mixed and repeated
  1117 freely;
  1118 
  1119 * Database of theorems for FOL, HOL and ZF.  New
  1120 commands including qed, qed_goal and bind_thm store theorems in the database.
  1121 
  1122 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1123 a given theory (thms_of), or find out what theory a theorem was proved in
  1124 (theory_of_thm);
  1125 
  1126 * Bugs fixed in the inductive definition and datatype packages;
  1127 
  1128 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1129 and HOL_dup_cs obsolete;
  1130 
  1131 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1132 have been removed;
  1133 
  1134 * Simpler definition of function space in ZF;
  1135 
  1136 * new results about cardinal and ordinal arithmetic in ZF;
  1137 
  1138 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1139 types;
  1140 
  1141 
  1142 $Id$