2 Isabelle NEWS -- history user-relevant changes
3 ==============================================
5 New in this Isabelle version
6 ----------------------------
9 New in Isabelle99 (October 1999)
10 --------------------------------
12 *** Overview of INCOMPATIBILITIES (see below for more details) ***
14 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
15 are no longer simplified. (This allows the simplifier to unfold recursive
16 functional programs.) To restore the old behaviour, declare
18 Delcongs [if_weak_cong];
20 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
23 * HOL: the predicate "inj" is now defined by translation to "inj_on";
25 * HOL/datatype: mutual_induct_tac no longer exists --
26 use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
28 * HOL/typedef: fixed type inference for representing set; type
29 arguments now have to occur explicitly on the rhs as type constraints;
31 * ZF: The con_defs part of an inductive definition may no longer refer
32 to constants declared in the same theory;
34 * HOL, ZF: the function mk_cases, generated by the inductive
35 definition package, has lost an argument. To simplify its result, it
36 uses the default simpset instead of a supplied list of theorems.
38 * HOL/List: the constructors of type list are now Nil and Cons;
40 * Simplifier: the type of the infix ML functions
41 setSSolver addSSolver setSolver addSolver
42 is now simpset * solver -> simpset where `solver' is a new abstract type
43 for packaging solvers. A solver is created via
44 mk_solver: string -> (thm list -> int -> tactic) -> solver
45 where the string argument is only a comment.
50 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
51 decision procedure for linear arithmetic. Currently it is used for
52 types `nat', `int', and `real' in HOL (see below); it can, should and
53 will be instantiated for other types and logics as well.
55 * The simplifier now accepts rewrite rules with flexible heads, eg
56 hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
57 They are applied like any rule with a non-pattern lhs, i.e. by first-order
63 * New Isabelle/Isar subsystem provides an alternative to traditional
64 tactical theorem proving; together with the ProofGeneral/isar user
65 interface it offers an interactive environment for developing human
66 readable proof documents (Isar == Intelligible semi-automated
67 reasoning); for further information see isatool doc isar-ref,
68 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
70 * improved presentation of theories: better HTML markup (including
71 colors), graph views in several sizes; isatool usedir now provides a
72 proper interface for user theories (via -P option); actual document
73 preparation based on (PDF)LaTeX is available as well (for new-style
74 theories only); see isatool doc system for more information;
76 * native support for Proof General, both for classic Isabelle and
79 * ML function thm_deps visualizes dependencies of theorems and lemmas,
80 using the graph browser tool;
82 * Isabelle manuals now also available as PDF;
84 * theory loader rewritten from scratch (may not be fully
85 bug-compatible); old loadpath variable has been replaced by show_path,
86 add_path, del_path, reset_path functions; new operations such as
87 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
90 * improved isatool install: option -k creates KDE application icon,
91 option -p DIR installs standalone binaries;
93 * added ML_PLATFORM setting (useful for cross-platform installations);
94 more robust handling of platform specific ML images for SML/NJ;
96 * the settings environment is now statically scoped, i.e. it is never
97 created again in sub-processes invoked from isabelle, isatool, or
100 * path element specification '~~' refers to '$ISABELLE_HOME';
102 * in locales, the "assumes" and "defines" parts may be omitted if
105 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
108 * new print_mode "HTML";
110 * new flag show_tags controls display of tags of theorems (which are
111 basically just comments that may be attached by some tools);
113 * Isamode 2.6 requires patch to accomodate change of Isabelle font
114 mode and goal output format:
116 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
118 < (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
120 > (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
121 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
123 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
125 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
127 * function bind_thms stores lists of theorems (cf. bind_thm);
129 * new shorthand tactics ftac, eatac, datac, fatac;
131 * qed (and friends) now accept "" as result name; in that case the
132 theorem is not stored, but proper checks and presentation of the
135 * theorem database now also indexes constants "Trueprop", "all",
136 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
143 * There are now decision procedures for linear arithmetic over nat and
146 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
147 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
148 are treated as atomic; subformulae not involving type `nat' or `int'
149 are ignored; quantified subformulae are ignored unless they are
150 positive universal or negative existential. The tactic has to be
151 invoked by hand and can be a little bit slow. In particular, the
152 running time is exponential in the number of occurrences of `min' and
153 `max', and `-' on `nat'.
155 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
156 (negated) (in)equalities among the premises and the conclusion into
157 account (i.e. no compound formulae) and does not know about `min' and
158 `max', and `-' on `nat'. It is fast and is used automatically by the
161 NB: At the moment, these decision procedures do not cope with mixed
162 nat/int formulae where the two parts interact, such as `m < n ==>
165 * HOL/Numeral provides a generic theory of numerals (encoded
166 efficiently as bit strings); setup for types nat/int/real is in place;
167 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
168 int, existing theories and proof scripts may require a few additional
171 * integer division and remainder can now be performed on constant
174 * many properties of integer multiplication, division and remainder
177 * An interface to the Stanford Validity Checker (SVC) is available through the
178 tactic svc_tac. Propositional tautologies and theorems of linear arithmetic
179 are proved automatically. SVC must be installed separately, and its results
180 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
181 invocation of the underlying oracle). For SVC see
182 http://verify.stanford.edu/SVC
184 * IsaMakefile: the HOL-Real target now builds an actual image;
189 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
190 (in Isabelle/Isar) -- by Gertrud Bauer;
192 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
193 analysis for assembly languages with subtypes;
195 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
196 -- avoids syntactic ambiguities and treats state, transition, and
197 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
198 changed syntax and (many) tactics;
200 * HOL/inductive: Now also handles more general introduction rules such
201 as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
202 theorems are now maintained within the theory (maintained via the
205 * HOL/datatype: Now also handles arbitrarily branching datatypes
206 (using function types) such as
208 datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
210 * HOL/record: record_simproc (part of the default simpset) takes care
211 of selectors applied to updated records; record_split_tac is no longer
212 part of the default claset; update_defs may now be removed from the
213 simpset in many cases; COMPATIBILITY: old behavior achieved by
215 claset_ref () := claset() addSWrapper record_split_wrapper;
216 Delsimprocs [record_simproc]
218 * HOL/typedef: fixed type inference for representing set; type
219 arguments now have to occur explicitly on the rhs as type constraints;
221 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
222 names rather than an ML expression;
224 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
225 supplied later. Program schemes can be defined, such as
226 "While B C s = (if B s then While B C (C s) else s)"
227 where the well-founded relation can be chosen after B and C have been given.
229 * HOL/List: the constructors of type list are now Nil and Cons;
230 INCOMPATIBILITY: while [] and infix # syntax is still there, of
231 course, ML tools referring to List.list.op # etc. have to be adapted;
233 * HOL_quantifiers flag superseded by "HOL" print mode, which is
234 disabled by default; run isabelle with option -m HOL to get back to
235 the original Gordon/HOL-style output;
237 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
238 ALL x<=y. P, EX x<y. P, EX x<=y. P;
240 * HOL basic syntax simplified (more orthogonal): all variants of
241 All/Ex now support plain / symbolic / HOL notation; plain syntax for
242 Eps operator is provided as well: "SOME x. P[x]";
244 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
246 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
247 thus available for user theories;
249 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
250 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
253 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
254 several times and then mp;
259 * the notation <<...>> is now available as a notation for sequences of
262 * the simplifier is now installed
264 * the axiom system has been generalized (thanks to Soren Heilmann)
266 * the classical reasoner now has a default rule database
271 * new primrec section allows primitive recursive functions to be given
272 directly (as in HOL) over datatypes and the natural numbers;
274 * new tactics induct_tac and exhaust_tac for induction (or case
275 analysis) over datatypes and the natural numbers;
277 * the datatype declaration of type T now defines the recursor T_rec;
279 * simplification automatically does freeness reasoning for datatype
282 * automatic type-inference, with AddTCs command to insert new
285 * datatype introduction rules are now added as Safe Introduction rules
288 * the syntax "if P then x else y" is now available in addition to
292 *** Internal programming interfaces ***
294 * tuned simplifier trace output; new flag debug_simp;
296 * structures Vartab / Termtab (instances of TableFun) offer efficient
297 tables indexed by indexname_ord / term_ord (compatible with aconv);
299 * AxClass.axclass_tac lost the theory argument;
301 * tuned current_goals_markers semantics: begin / end goal avoids
302 printing empty lines;
304 * removed prs and prs_fn hook, which was broken because it did not
305 include \n in its semantics, forcing writeln to add one
306 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
307 string -> unit if you really want to output text without newline;
309 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
310 plain output, interface builders may have to enable 'isabelle_font'
311 mode to get Isabelle font glyphs as before;
313 * refined token_translation interface; INCOMPATIBILITY: output length
314 now of type real instead of int;
316 * theory loader actions may be traced via new ThyInfo.add_hook
317 interface (see src/Pure/Thy/thy_info.ML); example application: keep
318 your own database of information attached to *whole* theories -- as
319 opposed to intra-theory data slots offered via TheoryDataFun;
321 * proper handling of dangling sort hypotheses (at last!);
322 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
323 extra sort hypotheses that can be witnessed from the type signature;
324 the force_strip_shyps flag is gone, any remaining shyps are simply
325 left in the theorem (with a warning issued by strip_shyps_warning);
329 New in Isabelle98-1 (October 1998)
330 ----------------------------------
332 *** Overview of INCOMPATIBILITIES (see below for more details) ***
334 * several changes of automated proof tools;
336 * HOL: major changes to the inductive and datatype packages, including
337 some minor incompatibilities of theory syntax;
339 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
342 * HOL: removed duplicate thms in Arith:
343 less_imp_add_less should be replaced by trans_less_add1
344 le_imp_add_le should be replaced by trans_le_add1
346 * HOL: unary minus is now overloaded (new type constraints may be
349 * HOL and ZF: unary minus for integers is now #- instead of #~. In
350 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
351 now taken as an integer constant.
353 * Pure: ML function 'theory_of' renamed to 'theory';
359 1. Asm_full_simp_tac is now more aggressive.
360 1. It will sometimes reorient premises if that increases their power to
362 2. It does no longer proceed strictly from left to right but may also
363 rotate premises to achieve further simplification.
364 For compatibility reasons there is now Asm_lr_simp_tac which is like the
365 old Asm_full_simp_tac in that it does not rotate premises.
366 2. The simplifier now knows a little bit about nat-arithmetic.
368 * Classical reasoner: wrapper mechanism for the classical reasoner now
369 allows for selected deletion of wrappers, by introduction of names for
370 wrapper functionals. This implies that addbefore, addSbefore,
371 addaltern, and addSaltern now take a pair (name, tactic) as argument,
372 and that adding two tactics with the same name overwrites the first
373 one (emitting a warning).
374 type wrapper = (int -> tactic) -> (int -> tactic)
375 setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
376 addWrapper, addSWrapper: claset * (string * wrapper) -> claset
377 delWrapper, delSWrapper: claset * string -> claset
378 getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
380 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
381 semantics; addbefore now affects only the unsafe part of step_tac
382 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
383 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
386 * Classical reasoner: setwrapper to setWrapper and compwrapper to
387 compWrapper; added safe wrapper (and access functions for it);
389 * HOL/split_all_tac is now much faster and fails if there is nothing
390 to split. Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
391 and the names of the automatically generated variables have changed.
392 split_all_tac has moved within claset() from unsafe wrappers to safe
393 wrappers, which means that !!-bound variables are split much more
394 aggressively, and safe_tac and clarify_tac now split such variables.
395 If this splitting is not appropriate, use delSWrapper "split_all_tac".
396 Note: the same holds for record_split_tac, which does the job of
397 split_all_tac for record fields.
399 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
400 permanently to the default simpset using Addsplits just like
401 Addsimps. They can be removed via Delsplits just like
402 Delsimps. Lower-case versions are also available.
404 * HOL/Simplifier: The rule split_if is now part of the default
405 simpset. This means that the simplifier will eliminate all occurrences
406 of if-then-else in the conclusion of a goal. To prevent this, you can
407 either remove split_if completely from the default simpset by
408 `Delsplits [split_if]' or remove it in a specific call of the
409 simplifier using `... delsplits [split_if]'. You can also add/delete
410 other case splitting rules to/from the default simpset: every datatype
411 generates suitable rules `split_t_case' and `split_t_case_asm' (where
412 t is the name of the datatype).
414 * Classical reasoner / Simplifier combination: new force_tac (and
415 derivatives Force_tac, force) combines rewriting and classical
416 reasoning (and whatever other tools) similarly to auto_tac, but is
417 aimed to solve the given subgoal completely.
422 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
423 and `goalw': the theory is no longer needed as an explicit argument -
424 the current theory context is used; assumptions are no longer returned
425 at the ML-level unless one of them starts with ==> or !!; it is
426 recommended to convert to these new commands using isatool fixgoal
427 (backup your sources first!);
429 * new top-level commands 'thm' and 'thms' for retrieving theorems from
430 the current theory context, and 'theory' to lookup stored theories;
432 * new theory section 'locale' for declaring constants, assumptions and
433 definitions that have local scope;
435 * new theory section 'nonterminals' for purely syntactic types;
437 * new theory section 'setup' for generic ML setup functions
438 (e.g. package initialization);
440 * the distribution now includes Isabelle icons: see
441 lib/logo/isabelle-{small,tiny}.xpm;
443 * isatool install - install binaries with absolute references to
446 * isatool logo -- create instances of the Isabelle logo (as EPS);
448 * print mode 'emacs' reserved for Isamode;
450 * support multiple print (ast) translations per constant name;
452 * theorems involving oracles are now printed with a suffixed [!];
457 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
459 * HOL/inductive package reorganized and improved: now supports mutual
465 oddI "n : EVEN ==> Suc n : ODD"
466 evenI "n : ODD ==> Suc n : EVEN"
468 new theorem list "elims" contains an elimination rule for each of the
469 recursive sets; inductive definitions now handle disjunctive premises
472 INCOMPATIBILITIES: requires Inductive as an ancestor; component
473 "mutual_induct" no longer exists - the induction rule is always
474 contained in "induct";
477 * HOL/datatype package re-implemented and greatly improved: now
478 supports mutually recursive datatypes such as
481 'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
482 | SUM ('a aexp) ('a aexp)
483 | DIFF ('a aexp) ('a aexp)
486 'a bexp = LESS ('a aexp) ('a aexp)
487 | AND ('a bexp) ('a bexp)
488 | OR ('a bexp) ('a bexp)
490 as well as indirectly recursive datatypes such as
493 ('a, 'b) term = Var 'a
494 | App 'b ((('a, 'b) term) list)
496 The new tactic mutual_induct_tac [<var_1>, ..., <var_n>] i performs
497 induction on mutually / indirectly recursive datatypes.
499 Primrec equations are now stored in theory and can be accessed via
500 <function_name>.simps.
504 - Theories using datatypes must now have theory Datatype as an
506 - The specific <typename>.induct_tac no longer exists - use the
507 generic induct_tac instead.
508 - natE has been renamed to nat.exhaust - use exhaust_tac
509 instead of res_inst_tac ... natE. Note that the variable
510 names in nat.exhaust differ from the names in natE, this
511 may cause some "fragile" proofs to fail.
512 - The theorems split_<typename>_case and split_<typename>_case_asm
513 have been renamed to <typename>.split and <typename>.split_asm.
514 - Since default sorts of type variables are now handled correctly,
515 some datatype definitions may have to be annotated with explicit
517 - Primrec definitions no longer require function name and type
518 of recursive argument.
520 Consider using isatool fixdatatype to adapt your theories and proof
521 scripts to the new package (backup your sources first!).
524 * HOL/record package: considerably improved implementation; now
525 includes concrete syntax for record types, terms, updates; theorems
526 for surjective pairing and splitting !!-bound record variables; proof
527 support is as follows:
529 1) standard conversions (selectors or updates applied to record
530 constructor terms) are part of the standard simpset;
532 2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
533 made part of standard simpset and claset via addIffs;
535 3) a tactic for record field splitting (record_split_tac) is part of
536 the standard claset (addSWrapper);
538 To get a better idea about these rules you may retrieve them via
539 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
540 the name of your record type.
542 The split tactic 3) conceptually simplifies by the following rule:
544 "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
546 Thus any record variable that is bound by meta-all will automatically
547 blow up into some record constructor term, consequently the
548 simplifications of 1), 2) apply. Thus force_tac, auto_tac etc. shall
549 solve record problems automatically.
552 * reorganized the main HOL image: HOL/Integ and String loaded by
553 default; theory Main includes everything;
555 * automatic simplification of integer sums and comparisons, using cancellation;
557 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
559 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
561 * many new identities for unions, intersections, set difference, etc.;
563 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
564 called split_if, split_split, split_sum_case and split_nat_case (to go
567 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
568 (?x::unit) = (); this is made part of the default simpset, which COULD
569 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
570 'Delsimprocs [unit_eq_proc];' as last resort); also note that
571 unit_abs_eta_conv is added in order to counter the effect of
572 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
575 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
578 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
579 It and 'sym RS equals0D' are now in the default claset, giving automatic
580 disjointness reasoning but breaking a few old proofs.
582 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
583 to 'converse' from 'inverse' (for compatibility with ZF and some
586 * HOL/recdef can now declare non-recursive functions, with {} supplied as
587 the well-founded relation;
589 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
590 Compl A. The "Compl" syntax remains available as input syntax for this
593 * HOL/Update: new theory of function updates:
594 f(a:=b) == %x. if x=a then b else f x
595 may also be iterated as in f(a:=b,c:=d,...);
597 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
600 - new function list_update written xs[i:=v] that updates the i-th
601 list position. May also be iterated as in xs[i:=a,j:=b,...].
602 - new function `upt' written [i..j(] which generates the list
603 [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
604 bound write [i..j], which is a shorthand for [i..j+1(].
605 - new lexicographic orderings and corresponding wellfoundedness theorems.
608 - removed 'pred' (predecessor) function;
609 - generalized some theorems about n-1;
610 - many new laws about "div" and "mod";
611 - new laws about greatest common divisors (see theory ex/Primes);
613 * HOL/Relation: renamed the relational operator r^-1 "converse"
614 instead of "inverse";
616 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
617 of the multiset ordering;
619 * directory HOL/Real: a construction of the reals using Dedekind cuts
620 (not included by default);
622 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
624 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
625 programs, i.e. different program variables may have different types.
627 * calling (stac rew i) now fails if "rew" has no effect on the goal
628 [previously, this check worked only if the rewrite rule was unconditional]
629 Now rew can involve either definitions or equalities (either == or =).
634 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
635 only the theorems proved on ZF.ML;
637 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
638 It and 'sym RS equals0D' are now in the default claset, giving automatic
639 disjointness reasoning but breaking a few old proofs.
641 * ZF/Update: new theory of function updates
642 with default rewrite rule f(x:=y) ` z = if(z=x, y, f`z)
643 may also be iterated as in f(a:=b,c:=d,...);
645 * in let x=t in u(x), neither t nor u(x) has to be an FOL term.
647 * calling (stac rew i) now fails if "rew" has no effect on the goal
648 [previously, this check worked only if the rewrite rule was unconditional]
649 Now rew can involve either definitions or equalities (either == or =).
651 * case_tac provided for compatibility with HOL
652 (like the old excluded_middle_tac, but with subgoals swapped)
655 *** Internal programming interfaces ***
657 * Pure: several new basic modules made available for general use, see
658 also src/Pure/README;
660 * improved the theory data mechanism to support encapsulation (data
661 kind name replaced by private Object.kind, acting as authorization
662 key); new type-safe user interface via functor TheoryDataFun; generic
663 print_data function becomes basically useless;
665 * removed global_names compatibility flag -- all theory declarations
666 are qualified by default;
668 * module Pure/Syntax now offers quote / antiquote translation
669 functions (useful for Hoare logic etc. with implicit dependencies);
670 see HOL/ex/Antiquote for an example use;
672 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
675 * new tactical CHANGED_GOAL for checking that a tactic modifies a
678 * Display.print_goals function moved to Locale.print_goals;
680 * standard print function for goals supports current_goals_markers
681 variable for marking begin of proof, end of proof, start of goal; the
682 default is ("", "", ""); setting current_goals_markers := ("<proof>",
683 "</proof>", "<goal>") causes SGML like tagged proof state printing,
688 New in Isabelle98 (January 1998)
689 --------------------------------
691 *** Overview of INCOMPATIBILITIES (see below for more details) ***
693 * changed lexical syntax of terms / types: dots made part of long
694 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
696 * simpset (and claset) reference variable replaced by functions
697 simpset / simpset_ref;
699 * no longer supports theory aliases (via merge) and non-trivial
700 implicit merge of thms' signatures;
702 * most internal names of constants changed due to qualified names;
704 * changed Pure/Sequence interface (see Pure/seq.ML);
707 *** General Changes ***
709 * hierachically structured name spaces (for consts, types, axms, thms
710 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
711 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
712 isatool fixdots ensures space after dots (e.g. "%x. x"); set
713 long_names for fully qualified output names; NOTE: ML programs
714 (special tactics, packages etc.) referring to internal names may have
715 to be adapted to cope with fully qualified names; in case of severe
716 backward campatibility problems try setting 'global_names' at compile
717 time to have enrything declared within a flat name space; one may also
718 fine tune name declarations in theories via the 'global' and 'local'
721 * reimplemented the implicit simpset and claset using the new anytype
722 data filed in signatures; references simpset:simpset ref etc. are
723 replaced by functions simpset:unit->simpset and
724 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
725 to patch your ML files accordingly;
727 * HTML output now includes theory graph data for display with Java
728 applet or isatool browser; data generated automatically via isatool
729 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
731 * defs may now be conditional; improved rewrite_goals_tac to handle
732 conditional equations;
734 * defs now admits additional type arguments, using TYPE('a) syntax;
736 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
737 creates a new theory node; implicit merge of thms' signatures is
738 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
739 transfer:theory->thm->thm in (rare) cases;
741 * improved handling of draft signatures / theories; draft thms (and
742 ctyps, cterms) are automatically promoted to real ones;
744 * slightly changed interfaces for oracles: admit many per theory, named
745 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
747 * print_goals: optional output of const types (set show_consts and
750 * improved output of warnings (###) and errors (***);
752 * subgoal_tac displays a warning if the new subgoal has type variables;
754 * removed old README and Makefiles;
756 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
758 * removed obsolete init_pps and init_database;
760 * deleted the obsolete tactical STATE, which was declared by
761 fun STATE tacfun st = tacfun st st;
763 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
764 (which abbreviates $HOME);
766 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
767 use isatool fixseq to adapt your ML programs (this works for fully
768 qualified references to the Sequence structure only!);
770 * use_thy no longer requires writable current directory; it always
771 reloads .ML *and* .thy file, if either one is out of date;
774 *** Classical Reasoner ***
776 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
777 tactics that use classical reasoning to simplify a subgoal without
778 splitting it into several subgoals;
780 * Safe_tac: like safe_tac but uses the default claset;
785 * added simplification meta rules:
786 (asm_)(full_)simplify: simpset -> thm -> thm;
788 * simplifier.ML no longer part of Pure -- has to be loaded by object
791 * added prems argument to simplification procedures;
793 * HOL, FOL, ZF: added infix function `addsplits':
794 instead of `<simpset> setloop (split_tac <thms>)'
795 you can simply write `<simpset> addsplits <thms>'
800 * TYPE('a) syntax for type reflection terms;
802 * no longer handles consts with name "" -- declare as 'syntax' instead;
804 * pretty printer: changed order of mixfix annotation preference (again!);
806 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
811 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
812 with `addloop' of the simplifier to faciliate case splitting in premises.
814 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
816 * HOL/Auth: new protocol proofs including some for the Internet
819 * HOL/Map: new theory of `maps' a la VDM;
821 * HOL/simplifier: simplification procedures nat_cancel_sums for
822 cancelling out common nat summands from =, <, <= (in)equalities, or
823 differences; simplification procedures nat_cancel_factor for
824 cancelling common factor from =, <, <= (in)equalities over natural
825 sums; nat_cancel contains both kinds of procedures, it is installed by
826 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
828 * HOL/simplifier: terms of the form
829 `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)' (or t=x)
831 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
832 and those of the form
833 `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)' (or t=x)
835 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
838 Each datatype `t' now comes with a theorem `split_t_case' of the form
840 P(t_case f1 ... fn x) =
841 ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
843 (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
846 and a theorem `split_t_case_asm' of the form
848 P(t_case f1 ... fn x) =
849 ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
851 (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
853 which can be added to a simpset via `addsplits'. The existing theorems
854 expand_list_case and expand_option_case have been renamed to
855 split_list_case and split_option_case.
858 - `pred n' is automatically converted to `n-1'.
859 Users are strongly encouraged not to use `pred' any longer,
860 because it will disappear altogether at some point.
861 - Users are strongly encouraged to write "0 < n" rather than
862 "n ~= 0". Theorems and proof tools have been modified towards this
866 the function "set_of_list" has been renamed "set" (and its theorems too);
867 the function "nth" now takes its arguments in the reverse order and
868 has acquired the infix notation "!" as in "xs!n".
870 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
872 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
873 specialist theorems (like UN1_I) are gone. Similarly for (INT x.B x);
875 * HOL/record: extensible records with schematic structural subtyping
876 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
877 still lacks various theorems and concrete record syntax;
882 * removed "axioms" and "generated by" sections;
884 * replaced "ops" section by extended "consts" section, which is capable of
885 handling the continuous function space "->" directly;
888 . proves theorems immediately and stores them in the theory,
889 . creates hierachical name space,
890 . now uses normal mixfix annotations (instead of cinfix...),
891 . minor changes to some names and values (for consistency),
892 . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
893 . separator between mutual domain defs: changed "," to "and",
894 . improved handling of sort constraints; now they have to
895 appear on the left-hand side of the equations only;
897 * fixed LAM <x,y,zs>.b syntax;
899 * added extended adm_tac to simplifier in HOLCF -- can now discharge
900 adm (%x. P (t x)), where P is chainfinite and t continuous;
905 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
906 with `addloop' of the simplifier to faciliate case splitting in premises.
908 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
909 in HOL, they strip ALL and --> from proved theorems;
913 New in Isabelle94-8 (May 1997)
914 ------------------------------
916 *** General Changes ***
918 * new utilities to build / run / maintain Isabelle etc. (in parts
919 still somewhat experimental); old Makefiles etc. still functional;
921 * new 'Isabelle System Manual';
923 * INSTALL text, together with ./configure and ./build scripts;
925 * reimplemented type inference for greater efficiency, better error
926 messages and clean internal interface;
928 * prlim command for dealing with lots of subgoals (an easier way of
929 setting goals_limit);
934 * supports alternative (named) syntax tables (parser and pretty
935 printer); internal interface is provided by add_modesyntax(_i);
937 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
938 be used in conjunction with the Isabelle symbol font; uses the
939 "symbols" syntax table;
941 * added token_translation interface (may translate name tokens in
942 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
943 the current print_mode); IMPORTANT: user print translation functions
944 are responsible for marking newly introduced bounds
945 (Syntax.mark_boundT);
947 * token translations for modes "xterm" and "xterm_color" that display
948 names in bold, underline etc. or colors (which requires a color
951 * infixes may now be declared with names independent of their syntax;
953 * added typed_print_translation (like print_translation, but may
954 access type of constant);
957 *** Classical Reasoner ***
959 Blast_tac: a new tactic! It is often more powerful than fast_tac, but has
960 some limitations. Blast_tac...
961 + ignores addss, addbefore, addafter; this restriction is intrinsic
962 + ignores elimination rules that don't have the correct format
963 (the conclusion MUST be a formula variable)
964 + ignores types, which can make HOL proofs fail
965 + rules must not require higher-order unification, e.g. apply_type in ZF
966 [message "Function Var's argument not a bound variable" relates to this]
967 + its proof strategy is more general but can actually be slower
969 * substitution with equality assumptions no longer permutes other
972 * minor changes in semantics of addafter (now called addaltern); renamed
973 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
974 (and access functions for it);
976 * improved combination of classical reasoner and simplifier:
977 + functions for handling clasimpsets
978 + improvement of addss: now the simplifier is called _after_ the
980 + safe variant of addss called addSss: uses safe simplifications
981 _during_ the safe steps. It is more complete as it allows multiple
982 instantiations of unknowns (e.g. with slow_tac).
986 * added interface for simplification procedures (functions that
987 produce *proven* rewrite rules on the fly, depending on current
990 * ordering on terms as parameter (used for ordered rewriting);
992 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
994 * the solver is now split into a safe and an unsafe part.
995 This should be invisible for the normal user, except that the
996 functions setsolver and addsolver have been renamed to setSolver and
997 addSolver; added safe_asm_full_simp_tac;
1002 * a generic induction tactic `induct_tac' which works for all datatypes and
1003 also for type `nat';
1005 * a generic case distinction tactic `exhaust_tac' which works for all
1006 datatypes and also for type `nat';
1008 * each datatype comes with a function `size';
1010 * patterns in case expressions allow tuple patterns as arguments to
1011 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
1013 * primrec now also works with type nat;
1015 * recdef: a new declaration form, allows general recursive functions to be
1016 defined in theory files. See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
1018 * the constant for negation has been renamed from "not" to "Not" to
1019 harmonize with FOL, ZF, LK, etc.;
1021 * HOL/ex/LFilter theory of a corecursive "filter" functional for
1024 * HOL/Modelcheck demonstrates invocation of model checker oracle;
1026 * HOL/ex/Ring.thy declares cring_simp, which solves equational
1027 problems in commutative rings, using axiomatic type classes for + and *;
1029 * more examples in HOL/MiniML and HOL/Auth;
1031 * more default rewrite rules for quantifiers, union/intersection;
1033 * a new constant `arbitrary == @x.False';
1035 * HOLCF/IOA replaces old HOL/IOA;
1037 * HOLCF changes: derived all rules and arities
1038 + axiomatic type classes instead of classes
1039 + typedef instead of faking type definitions
1040 + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
1041 + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
1042 + eliminated the types void, one, tr
1043 + use unit lift and bool lift (with translations) instead of one and tr
1044 + eliminated blift from Lift3.thy (use Def instead of blift)
1045 all eliminated rules are derived as theorems --> no visible changes ;
1050 * ZF now has Fast_tac, Simp_tac and Auto_tac. Union_iff is a now a default
1051 rewrite rule; this may affect some proofs. eq_cs is gone but can be put back
1052 as ZF_cs addSIs [equalityI];
1056 New in Isabelle94-7 (November 96)
1057 ---------------------------------
1059 * allowing negative levels (as offsets) in prlev and choplev;
1061 * super-linear speedup for large simplifications;
1063 * FOL, ZF and HOL now use miniscoping: rewriting pushes
1064 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
1065 FAIL); can suppress it using the command Delsimps (ex_simps @
1066 all_simps); De Morgan laws are also now included, by default;
1068 * improved printing of ==> : ~:
1070 * new object-logic "Sequents" adds linear logic, while replacing LK
1071 and Modal (thanks to Sara Kalvala);
1073 * HOL/Auth: correctness proofs for authentication protocols;
1075 * HOL: new auto_tac combines rewriting and classical reasoning (many
1076 examples on HOL/Auth);
1078 * HOL: new command AddIffs for declaring theorems of the form P=Q to
1079 the rewriter and classical reasoner simultaneously;
1081 * function uresult no longer returns theorems in "standard" format;
1082 regain previous version by: val uresult = standard o uresult;
1089 * oracles -- these establish an interface between Isabelle and trusted
1090 external reasoners, which may deliver results as theorems;
1092 * proof objects (in particular record all uses of oracles);
1094 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
1096 * "constdefs" section in theory files;
1098 * "primrec" section (HOL) no longer requires names;
1100 * internal type "tactic" now simply "thm -> thm Sequence.seq";
1107 * reduced space requirements;
1109 * automatic HTML generation from theories;
1111 * theory files no longer require "..." (quotes) around most types;
1113 * new examples, including two proofs of the Church-Rosser theorem;
1115 * non-curried (1994) version of HOL is no longer distributed;
1122 * greatly reduced space requirements;
1124 * theory files (.thy) no longer require \...\ escapes at line breaks;
1126 * searchable theorem database (see the section "Retrieving theorems" on
1127 page 8 of the Reference Manual);
1129 * new examples, including Grabczewski's monumental case study of the
1132 * The previous version of HOL renamed to Old_HOL;
1134 * The new version of HOL (previously called CHOL) uses a curried syntax
1135 for functions. Application looks like f a b instead of f(a,b);
1137 * Mutually recursive inductive definitions finally work in HOL;
1139 * In ZF, pattern-matching on tuples is now available in all abstractions and
1140 translates to the operator "split";
1147 * new infix operator, addss, allowing the classical reasoner to
1148 perform simplification at each step of its search. Example:
1149 fast_tac (cs addss ss)
1151 * a new logic, CHOL, the same as HOL, but with a curried syntax
1152 for functions. Application looks like f a b instead of f(a,b). Also pairs
1153 look like (a,b) instead of <a,b>;
1155 * PLEASE NOTE: CHOL will eventually replace HOL!
1157 * In CHOL, pattern-matching on tuples is now available in all abstractions.
1158 It translates to the operator "split". A new theory of integers is available;
1160 * In ZF, integer numerals now denote two's-complement binary integers.
1161 Arithmetic operations can be performed by rewriting. See ZF/ex/Bin.ML;
1163 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
1164 of the Axiom of Choice;
1171 * Significantly faster resolution;
1173 * the different sections in a .thy file can now be mixed and repeated
1176 * Database of theorems for FOL, HOL and ZF. New
1177 commands including qed, qed_goal and bind_thm store theorems in the database.
1179 * Simple database queries: return a named theorem (get_thm) or all theorems of
1180 a given theory (thms_of), or find out what theory a theorem was proved in
1183 * Bugs fixed in the inductive definition and datatype packages;
1185 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
1186 and HOL_dup_cs obsolete;
1188 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
1191 * Simpler definition of function space in ZF;
1193 * new results about cardinal and ordinal arithmetic in ZF;
1195 * 'subtype' facility in HOL for introducing new types as subsets of existing