NEWS
author wenzelm
Fri Apr 16 21:00:07 2004 +0200 (2004-04-16)
changeset 14606 0be6c11e7128
parent 14602 e06ded775eca
child 14610 9c2e31e483b2
permissions -rw-r--r--
Pure: 'instance' now handles general arities;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in Isabelle2004 (April 2004)
     5 --------------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    10   Replaces linorder.ML.
    11 
    12 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
    13   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
    14   (\<a>...\<z>), are now considered normal letters, and can therefore
    15   be used anywhere where an ASCII letter (a...zA...Z) has until
    16   now. COMPATIBILITY: This obviously changes the parsing of some
    17   terms, especially where a symbol has been used as a binder, say
    18   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    19   as an identifier.  Fix it by inserting a space around former
    20   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    21   existing theory and ML files.
    22 
    23 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    24 
    25 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    26   allowed in identifiers. Similar to Greek letters \<^isub> is now considered 
    27   a normal (but invisible) letter. For multiple letter subscripts repeat 
    28   \<^isub> like this: x\<^isub>1\<^isub>2. 
    29 
    30 * Pure: There are now sub-/superscripts that can span more than one
    31   character. Text between \<^bsub> and \<^esub> is set in subscript in
    32   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
    33   superscript. The new control characters are not identifier parts.
    34 
    35 * Pure: Control-symbols of the form \<^raw:...> will literally print the
    36   content of "..." to the latex file instead of \isacntrl... . The "..."
    37   may consist of any printable characters excluding the end bracket >.
    38 
    39 * Pure: Using new Isar command "finalconsts" (or the ML functions
    40   Theory.add_finals or Theory.add_finals_i) it is now possible to
    41   declare constants "final", which prevents their being given a definition
    42   later.  It is useful for constants whose behaviour is fixed axiomatically
    43   rather than definitionally, such as the meta-logic connectives.
    44 
    45 * Pure: 'instance' now handles general arities with general sorts
    46   (i.e. intersections of classes),
    47 
    48 * Presentation: generated HTML now uses a CSS style sheet to make layout
    49   (somewhat) independent of content. It is copied from lib/html/isabelle.css. 
    50   It can be changed to alter the colors/layout of generated pages.
    51 
    52 
    53 *** Isar ***
    54 
    55 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
    56   cut_tac, subgoal_tac and thin_tac:
    57   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    58     locales are no longer forced to write Isar proof scripts.
    59     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    60     emulations.
    61   - INCOMPATIBILITY: names of variables to be instantiated may no
    62     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    63     This is consistent with the instantiation attribute "where".
    64 
    65 * Attributes "where" and "of":
    66   - Now take type variables of instantiated theorem into account when reading
    67     the instantiation string.  This fixes a bug that caused instantiated
    68     theorems to have too special types in some circumstances.
    69   - "where" permits explicit instantiations of type variables.
    70 
    71 * Calculation commands "moreover" and "also" no longer interfere with
    72   current facts ("this"), admitting arbitrary combinations with "then"
    73   and derived forms.
    74 
    75 * Locales:
    76   - Goal statements involving the context element "includes" no longer
    77     generate theorems with internal delta predicates (those ending on
    78     "_axioms") in the premise.
    79     Resolve particular premise with <locale>.intro to obtain old form.
    80   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    81     specification and "includes" elements in goal statement.
    82   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    83     [intro?] and [elim?] (respectively) by default.
    84   - Experimental command for instantiation of locales in proof contexts:
    85         instantiate <label>[<attrs>]: <loc>
    86     Instantiates locale <loc> and adds all its theorems to the current context
    87     taking into account their attributes.  Label and attrs are optional
    88     modifiers, like in theorem declarations.  If present, names of
    89     instantiated theorems are qualified with <label>, and the attributes
    90     <attrs> are applied after any attributes these theorems might have already.
    91       If the locale has assumptions, a chained fact of the form
    92     "<loc> t1 ... tn" is expected from which instantiations of the parameters
    93     are derived.  The command does not support old-style locales declared
    94     with "locale (open)".
    95       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
    96 
    97 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    98   (Isar) contexts.
    99 
   100 
   101 *** HOL ***
   102 
   103 * Simplifier:
   104   - Much improved handling of linear and partial orders.
   105     Reasoners for linear and partial orders are set up for type classes
   106     "linorder" and "order" respectively, and are added to the default simpset
   107     as solvers.  This means that the simplifier can build transitivity chains
   108     to solve goals from the assumptions.
   109   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   110     of blast or auto after simplification become unnecessary because the goal
   111     is solved by simplification already.
   112 
   113 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   114     all proved in axiomatic type classes for semirings, rings and fields.
   115 
   116 * Numerics:
   117   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   118     now formalized using the Ring_and_Field theory mentioned above. 
   119   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   120     than before, because now they are set up once in a generic manner.
   121   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   122     Look for the general versions in Ring_and_Field (and Power if they concern
   123     exponentiation).
   124 
   125 * Type "rat" of the rational numbers is now available in HOL-Complex.
   126 
   127 * Records:
   128   - Record types are now by default printed with their type abbreviation
   129     instead of the list of all field types. This can be configured via
   130     the reference "print_record_type_abbr".
   131   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   132     (not enabled by default).
   133   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   134     EX x. x = sel r to True (not enabled by default).
   135   - Tactic "record_split_simp_tac" to split and simplify records added.
   136  
   137 * 'specification' command added, allowing for definition by
   138   specification.  There is also an 'ax_specification' command that
   139   introduces the new constants axiomatically.
   140 
   141 * arith(_tac) is now able to generate counterexamples for reals as well.
   142 
   143 * HOL-Algebra: new locale "ring" for non-commutative rings.
   144 
   145 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   146  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   147 
   148 * Unions and Intersections:
   149   The x-symbol output syntax of UN and INT has been changed
   150   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   151   i.e. the index formulae has become a subscript, like in normal math.
   152   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   153   The subscript version is also accepted as input syntax.
   154 
   155 * Unions and Intersections over Intervals:
   156   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   157   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   158   like in normal math, and corresponding versions for < and for intersection.
   159 
   160 * ML: the legacy theory structures Int and List have been removed. They had
   161   conflicted with ML Basis Library structures having the same names.
   162 
   163 * 'refute' command added to search for (finite) countermodels.  Only works
   164   for a fragment of HOL.  The installation of an external SAT solver is
   165   highly recommended.  See "HOL/Refute.thy" for details.
   166 
   167 * 'quickcheck' command: Allows to find counterexamples by evaluating
   168   formulae under an assignment of free variables to random values.
   169   In contrast to 'refute', it can deal with inductive datatypes,
   170   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   171   for examples.
   172 
   173 
   174 *** HOLCF ***
   175 
   176 * Streams now come with concatenation and are part of the HOLCF image
   177 
   178 
   179 
   180 New in Isabelle2003 (May 2003)
   181 ------------------------------
   182 
   183 *** General ***
   184 
   185 * Provers/simplifier:
   186 
   187   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   188     Assumptions are now subject to complete mutual simplification,
   189     not just from left to right. The simplifier now preserves
   190     the order of assumptions.
   191 
   192     Potential INCOMPATIBILITY:
   193 
   194     -- simp sometimes diverges where the old version did
   195        not, e.g. invoking simp on the goal
   196 
   197         [| P (f x); y = x; f x = f y |] ==> Q
   198 
   199        now gives rise to the infinite reduction sequence
   200 
   201         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   202 
   203        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   204        kind of problem.
   205 
   206     -- Tactics combining classical reasoner and simplification (such as auto)
   207        are also affected by this change, because many of them rely on
   208        simp. They may sometimes diverge as well or yield a different numbers
   209        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   210        in case of problems. Sometimes subsequent calls to the classical
   211        reasoner will fail because a preceeding call to the simplifier too
   212        eagerly simplified the goal, e.g. deleted redundant premises.
   213 
   214   - The simplifier trace now shows the names of the applied rewrite rules
   215 
   216   - You can limit the number of recursive invocations of the simplifier
   217     during conditional rewriting (where the simplifie tries to solve the
   218     conditions before applying the rewrite rule):
   219     ML "simp_depth_limit := n"
   220     where n is an integer. Thus you can force termination where previously
   221     the simplifier would diverge.
   222 
   223   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   224 
   225   - No longer aborts on failed congruence proof.  Instead, the
   226     congruence is ignored.
   227 
   228 * Pure: New generic framework for extracting programs from constructive
   229   proofs. See HOL/Extraction.thy for an example instantiation, as well
   230   as HOL/Extraction for some case studies.
   231 
   232 * Pure: The main goal of the proof state is no longer shown by default, only
   233 the subgoals. This behaviour is controlled by a new flag.
   234    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   235 (ML: Proof.show_main_goal).
   236 
   237 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   238 rules whose conclusion matches subgoal 1:
   239       PG menu: Isabelle/Isar -> Show me -> matching rules
   240 The rules are ordered by how closely they match the subgoal.
   241 In particular, rules that solve a subgoal outright are displayed first
   242 (or rather last, the way they are printed).
   243 (ML: ProofGeneral.print_intros())
   244 
   245 * Pure: New flag trace_unify_fail causes unification to print
   246 diagnostic information (PG: in trace buffer) when it fails. This is
   247 useful for figuring out why single step proofs like rule, erule or
   248 assumption failed.
   249 
   250 * Pure: Locale specifications now produce predicate definitions
   251 according to the body of text (covering assumptions modulo local
   252 definitions); predicate "loc_axioms" covers newly introduced text,
   253 while "loc" is cumulative wrt. all included locale expressions; the
   254 latter view is presented only on export into the global theory
   255 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   256 on the old view without predicates;
   257 
   258 * Pure: predefined locales "var" and "struct" are useful for sharing
   259 parameters (as in CASL, for example); just specify something like
   260 ``var x + var y + struct M'' as import;
   261 
   262 * Pure: improved thms_containing: proper indexing of facts instead of
   263 raw theorems; check validity of results wrt. current name space;
   264 include local facts of proof configuration (also covers active
   265 locales), cover fixed variables in index; may use "_" in term
   266 specification; an optional limit for the number of printed facts may
   267 be given (the default is 40);
   268 
   269 * Pure: disallow duplicate fact bindings within new-style theory files
   270 (batch-mode only);
   271 
   272 * Provers: improved induct method: assumptions introduced by case
   273 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   274 the goal statement); "foo" still refers to all facts collectively;
   275 
   276 * Provers: the function blast.overloaded has been removed: all constants
   277 are regarded as potentially overloaded, which improves robustness in exchange
   278 for slight decrease in efficiency;
   279 
   280 * Provers/linorder: New generic prover for transitivity reasoning over
   281 linear orders.  Note: this prover is not efficient!
   282 
   283 * Isar: preview of problems to finish 'show' now produce an error
   284 rather than just a warning (in interactive mode);
   285 
   286 
   287 *** HOL ***
   288 
   289 * arith(_tac)
   290 
   291  - Produces a counter example if it cannot prove a goal.
   292    Note that the counter example may be spurious if the goal is not a formula
   293    of quantifier-free linear arithmetic.
   294    In ProofGeneral the counter example appears in the trace buffer.
   295 
   296  - Knows about div k and mod k where k is a numeral of type nat or int.
   297 
   298  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   299    linear arithmetic fails. This takes account of quantifiers and divisibility.
   300    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   301 
   302 * simp's arithmetic capabilities have been enhanced a bit: it now
   303 takes ~= in premises into account (by performing a case split);
   304 
   305 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   306 are distributed over a sum of terms;
   307 
   308 * New tactic "trans_tac" and method "trans" instantiate
   309 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   310 "<=", "<" and "="). 
   311 
   312 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   313 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   314 
   315 * 'typedef' command has new option "open" to suppress the set
   316 definition;
   317 
   318 * functions Min and Max on finite sets have been introduced (theory
   319 Finite_Set);
   320 
   321 * attribute [symmetric] now works for relations as well; it turns
   322 (x,y) : R^-1 into (y,x) : R, and vice versa;
   323 
   324 * induct over a !!-quantified statement (say !!x1..xn):
   325   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   326 
   327 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   328 %x. None. Warning: empty_def now refers to the previously hidden definition
   329 of the empty set.
   330 
   331 * Algebra: formalization of classical algebra.  Intended as base for
   332 any algebraic development in Isabelle.  Currently covers group theory
   333 (up to Sylow's theorem) and ring theory (Universal Property of
   334 Univariate Polynomials).  Contributions welcome;
   335 
   336 * GroupTheory: deleted, since its material has been moved to Algebra;
   337 
   338 * Complex: new directory of the complex numbers with numeric constants, 
   339 nonstandard complex numbers, and some complex analysis, standard and 
   340 nonstandard (Jacques Fleuriot);
   341 
   342 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   343 
   344 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   345 Fleuriot);
   346 
   347 * Real/HahnBanach: updated and adapted to locales;
   348 
   349 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   350 Gray and Kramer);
   351 
   352 * UNITY: added the Meier-Sanders theory of progress sets;
   353 
   354 * MicroJava: bytecode verifier and lightweight bytecode verifier
   355 as abstract algorithms, instantiated to the JVM;
   356 
   357 * Bali: Java source language formalization. Type system, operational
   358 semantics, axiomatic semantics. Supported language features:
   359 classes, interfaces, objects,virtual methods, static methods,
   360 static/instance fields, arrays, access modifiers, definite
   361 assignment, exceptions.
   362 
   363 
   364 *** ZF ***
   365 
   366 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   367 universe, etc.);
   368 
   369 * Main ZF: virtually all theories converted to new-style format;
   370 
   371 
   372 *** ML ***
   373 
   374 * Pure: Tactic.prove provides sane interface for internal proofs;
   375 omits the infamous "standard" operation, so this is more appropriate
   376 than prove_goalw_cterm in many situations (e.g. in simprocs);
   377 
   378 * Pure: improved error reporting of simprocs;
   379 
   380 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   381 up simprocs;
   382 
   383 
   384 *** Document preparation ***
   385 
   386 * uses \par instead of \\ for line breaks in theory text. This may
   387 shift some page breaks in large documents. To get the old behaviour
   388 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   389 
   390 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   391 other packages
   392 
   393 * \<euro> now needs package babel/greek instead of marvosym (which
   394 broke \Rightarrow)
   395 
   396 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   397 textcomp package)
   398 
   399 
   400 
   401 New in Isabelle2002 (March 2002)
   402 --------------------------------
   403 
   404 *** Document preparation ***
   405 
   406 * greatly simplified document preparation setup, including more
   407 graceful interpretation of isatool usedir -i/-d/-D options, and more
   408 instructive isatool mkdir; users should basically be able to get
   409 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   410 users may run a separate document processing stage manually like this:
   411 "isatool usedir -D output HOL Test && isatool document Test/output";
   412 
   413 * theory dependency graph may now be incorporated into documents;
   414 isatool usedir -g true will produce session_graph.eps/.pdf for use
   415 with \includegraphics of LaTeX;
   416 
   417 * proper spacing of consecutive markup elements, especially text
   418 blocks after section headings;
   419 
   420 * support bold style (for single symbols only), input syntax is like
   421 this: "\<^bold>\<alpha>" or "\<^bold>A";
   422 
   423 * \<bullet> is now output as bold \cdot by default, which looks much
   424 better in printed text;
   425 
   426 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   427 note that these symbols are currently unavailable in Proof General /
   428 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   429 
   430 * isatool latex no longer depends on changed TEXINPUTS, instead
   431 isatool document copies the Isabelle style files to the target
   432 location;
   433 
   434 
   435 *** Isar ***
   436 
   437 * Pure/Provers: improved proof by cases and induction;
   438   - 'case' command admits impromptu naming of parameters (such as
   439     "case (Suc n)");
   440   - 'induct' method divinates rule instantiation from the inductive
   441     claim; no longer requires excessive ?P bindings for proper
   442     instantiation of cases;
   443   - 'induct' method properly enumerates all possibilities of set/type
   444     rules; as a consequence facts may be also passed through *type*
   445     rules without further ado;
   446   - 'induct' method now derives symbolic cases from the *rulified*
   447     rule (before it used to rulify cases stemming from the internal
   448     atomized version); this means that the context of a non-atomic
   449     statement becomes is included in the hypothesis, avoiding the
   450     slightly cumbersome show "PROP ?case" form;
   451   - 'induct' may now use elim-style induction rules without chaining
   452     facts, using ``missing'' premises from the goal state; this allows
   453     rules stemming from inductive sets to be applied in unstructured
   454     scripts, while still benefitting from proper handling of non-atomic
   455     statements; NB: major inductive premises need to be put first, all
   456     the rest of the goal is passed through the induction;
   457   - 'induct' proper support for mutual induction involving non-atomic
   458     rule statements (uses the new concept of simultaneous goals, see
   459     below);
   460   - append all possible rule selections, but only use the first
   461     success (no backtracking);
   462   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   463   - undeclared rule case names default to numbers 1, 2, 3, ...;
   464   - added 'print_induct_rules' (covered by help item in recent Proof
   465     General versions);
   466   - moved induct/cases attributes to Pure, methods to Provers;
   467   - generic method setup instantiated for FOL and HOL;
   468 
   469 * Pure: support multiple simultaneous goal statements, for example
   470 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   471 meta-level mechanism, this acts as if several individual goals had
   472 been stated separately; in particular common proof methods need to be
   473 repeated in order to cover all claims; note that a single elimination
   474 step is *not* sufficient to establish the two conjunctions, so this
   475 fails:
   476 
   477   assume "A & B" then have A and B ..   (*".." fails*)
   478 
   479 better use "obtain" in situations as above; alternative refer to
   480 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   481 
   482 * Pure: proper integration with ``locales''; unlike the original
   483 version by Florian Kammüller, Isar locales package high-level proof
   484 contexts rather than raw logical ones (e.g. we admit to include
   485 attributes everywhere); operations on locales include merge and
   486 rename; support for implicit arguments (``structures''); simultaneous
   487 type-inference over imports and text; see also HOL/ex/Locales.thy for
   488 some examples;
   489 
   490 * Pure: the following commands have been ``localized'', supporting a
   491 target locale specification "(in name)": 'lemma', 'theorem',
   492 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   493 stored both within the locale and at the theory level (exported and
   494 qualified by the locale name);
   495 
   496 * Pure: theory goals may now be specified in ``long'' form, with
   497 ad-hoc contexts consisting of arbitrary locale elements. for example
   498 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   499 definitions may be given, too); the result is a meta-level rule with
   500 the context elements being discharged in the obvious way;
   501 
   502 * Pure: new proof command 'using' allows to augment currently used
   503 facts after a goal statement ('using' is syntactically analogous to
   504 'apply', but acts on the goal's facts only); this allows chained facts
   505 to be separated into parts given before and after a claim, as in
   506 ``from a and b have C using d and e <proof>'';
   507 
   508 * Pure: renamed "antecedent" case to "rule_context";
   509 
   510 * Pure: new 'judgment' command records explicit information about the
   511 object-logic embedding (used by several tools internally); no longer
   512 use hard-wired "Trueprop";
   513 
   514 * Pure: added 'corollary' command;
   515 
   516 * Pure: fixed 'token_translation' command;
   517 
   518 * Pure: removed obsolete 'exported' attribute;
   519 
   520 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   521 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   522 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   523 
   524 * Pure: method 'atomize' presents local goal premises as object-level
   525 statements (atomic meta-level propositions); setup controlled via
   526 rewrite rules declarations of 'atomize' attribute; example
   527 application: 'induct' method with proper rule statements in improper
   528 proof *scripts*;
   529 
   530 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   531 now consider the syntactic context of assumptions, giving a better
   532 chance to get type-inference of the arguments right (this is
   533 especially important for locales);
   534 
   535 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   536 mode;
   537 
   538 * Pure/obtain: the formal conclusion "thesis", being marked as
   539 ``internal'', may no longer be reference directly in the text;
   540 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   541 situations;
   542 
   543 * Pure: generic 'sym' attribute which declares a rule both as pure
   544 'elim?' and for the 'symmetric' operation;
   545 
   546 * Pure: marginal comments ``--'' may now occur just anywhere in the
   547 text; the fixed correlation with particular command syntax has been
   548 discontinued;
   549 
   550 * Pure: new method 'rules' is particularly well-suited for proof
   551 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   552 but often produces more compact proof terms with less detours;
   553 
   554 * Pure/Provers/classical: simplified integration with pure rule
   555 attributes and methods; the classical "intro?/elim?/dest?"
   556 declarations coincide with the pure ones; the "rule" method no longer
   557 includes classically swapped intros; "intro" and "elim" methods no
   558 longer pick rules from the context; also got rid of ML declarations
   559 AddXIs/AddXEs/AddXDs; all of this has some potential for
   560 INCOMPATIBILITY;
   561 
   562 * Provers/classical: attribute 'swapped' produces classical inversions
   563 of introduction rules;
   564 
   565 * Provers/simplifier: 'simplified' attribute may refer to explicit
   566 rules instead of full simplifier context; 'iff' attribute handles
   567 conditional rules;
   568 
   569 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   570 
   571 * HOL: 'recdef' now fails on unfinished automated proofs, use
   572 "(permissive)" option to recover old behavior;
   573 
   574 * HOL: 'inductive' no longer features separate (collective) attributes
   575 for 'intros' (was found too confusing);
   576 
   577 * HOL: properly declared induction rules less_induct and
   578 wf_induct_rule;
   579 
   580 
   581 *** HOL ***
   582 
   583 * HOL: moved over to sane numeral syntax; the new policy is as
   584 follows:
   585 
   586   - 0 and 1 are polymorphic constants, which are defined on any
   587   numeric type (nat, int, real etc.);
   588 
   589   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   590   binary representation internally;
   591 
   592   - type nat has special constructor Suc, and generally prefers Suc 0
   593   over 1::nat and Suc (Suc 0) over 2::nat;
   594 
   595 This change may cause significant problems of INCOMPATIBILITY; here
   596 are some hints on converting existing sources:
   597 
   598   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   599   entities, so expressions involving "-" (unary or binary minus) need
   600   to be spaced properly;
   601 
   602   - existing occurrences of "1" may need to be constraint "1::nat" or
   603   even replaced by Suc 0; similar for old "2";
   604 
   605   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   606 
   607   - remove all special provisions on numerals in proofs;
   608 
   609 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   610 representation (depends on bin_arith_simps in the default context);
   611 
   612 * HOL: symbolic syntax for x^2 (numeral 2);
   613 
   614 * HOL: the class of all HOL types is now called "type" rather than
   615 "term"; INCOMPATIBILITY, need to adapt references to this type class
   616 in axclass/classes, instance/arities, and (usually rare) occurrences
   617 in typings (of consts etc.); internally the class is called
   618 "HOL.type", ML programs should refer to HOLogic.typeS;
   619 
   620 * HOL/record package improvements:
   621   - new derived operations "fields" to build a partial record section,
   622     "extend" to promote a fixed record to a record scheme, and
   623     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   624     declared as simp by default;
   625   - shared operations ("more", "fields", etc.) now need to be always
   626     qualified) --- potential INCOMPATIBILITY;
   627   - removed "make_scheme" operations (use "make" with "extend") --
   628     INCOMPATIBILITY;
   629   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   630   - provides cases/induct rules for use with corresponding Isar
   631     methods (for concrete records, record schemes, concrete more
   632     parts, and schematic more parts -- in that order);
   633   - internal definitions directly based on a light-weight abstract
   634     theory of product types over typedef rather than datatype;
   635 
   636 * HOL: generic code generator for generating executable ML code from
   637 specifications; specific support for HOL constructs such as inductive
   638 datatypes and sets, as well as recursive functions; can be invoked
   639 via 'generate_code' theory section;
   640 
   641 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   642 
   643 * HOL: consolidated and renamed several theories.  In particular:
   644 	Ord.thy has been absorbed into HOL.thy
   645 	String.thy has been absorbed into List.thy
   646  
   647 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   648 (beware of argument permutation!);
   649 
   650 * HOL: linorder_less_split superseded by linorder_cases;
   651 
   652 * HOL/List: "nodups" renamed to "distinct";
   653 
   654 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   655 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   656   - Ex_def has changed, now need to use some_eq_ex
   657 
   658 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   659 in this (rare) case use:
   660 
   661   delSWrapper "split_all_tac"
   662   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   663 
   664 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   665 MAY FAIL;
   666 
   667 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   668 Isabelle's type classes, ^ on functions and relations has too general
   669 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   670 necessary to attach explicit type constraints;
   671 
   672 * HOL/Relation: the prefix name of the infix "O" has been changed from
   673 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   674 renamed accordingly (eg "compI" -> "rel_compI").
   675 
   676 * HOL: syntax translations now work properly with numerals and records
   677 expressions;
   678 
   679 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   680 of "lam" -- INCOMPATIBILITY;
   681 
   682 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   683 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   684 renamed "Product_Type.unit";
   685 
   686 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   687 
   688 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   689 the "cases" method);
   690 
   691 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   692 Florian Kammüller);
   693 
   694 * HOL/IMP: updated and converted to new-style theory format; several
   695 parts turned into readable document, with proper Isar proof texts and
   696 some explanations (by Gerwin Klein);
   697 
   698 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   699 
   700 * HOL-Hyperreal is now a logic image;
   701 
   702 
   703 *** HOLCF ***
   704 
   705 * Isar: consts/constdefs supports mixfix syntax for continuous
   706 operations;
   707 
   708 * Isar: domain package adapted to new-style theory format, e.g. see
   709 HOLCF/ex/Dnat.thy;
   710 
   711 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   712 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   713 lift.induct_tac, always use UU instead of Undef;
   714 
   715 * HOLCF/IMP: updated and converted to new-style theory;
   716 
   717 
   718 *** ZF ***
   719 
   720 * Isar: proper integration of logic-specific tools and packages,
   721 including theory commands '(co)inductive', '(co)datatype',
   722 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   723 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   724 
   725 * theory Main no longer includes AC; for the Axiom of Choice, base
   726 your theory on Main_ZFC;
   727 
   728 * the integer library now covers quotients and remainders, with many
   729 laws relating division to addition, multiplication, etc.;
   730 
   731 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   732 typeless version of the formalism;
   733 
   734 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   735 format;
   736 
   737 * ZF/Induct: new directory for examples of inductive definitions,
   738 including theory Multiset for multiset orderings; converted to
   739 new-style theory format;
   740 
   741 * ZF: many new theorems about lists, ordinals, etc.;
   742 
   743 
   744 *** General ***
   745 
   746 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   747 variable proof controls level of detail: 0 = no proofs (only oracle
   748 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   749 also ref manual for further ML interfaces;
   750 
   751 * Pure/axclass: removed obsolete ML interface
   752 goal_subclass/goal_arity;
   753 
   754 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   755 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   756 separate tokens, so expressions involving minus need to be spaced
   757 properly;
   758 
   759 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   760 rather than "infixl" or "infixr";
   761 
   762 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   763 sort constraint specifications in type inference; e.g. "x::_::foo"
   764 ensures that the type of "x" is of sort "foo" (but not necessarily a
   765 type variable);
   766 
   767 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   768 control output of nested => (types); the default behavior is
   769 "type_brackets";
   770 
   771 * Pure/syntax: builtin parse translation for "_constify" turns valued
   772 tokens into AST constants;
   773 
   774 * Pure/syntax: prefer later declarations of translations and print
   775 translation functions; potential INCOMPATIBILITY: need to reverse
   776 multiple declarations for same syntax element constant;
   777 
   778 * Pure/show_hyps reset by default (in accordance to existing Isar
   779 practice);
   780 
   781 * Provers/classical: renamed addaltern to addafter, addSaltern to
   782 addSafter;
   783 
   784 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   785 as well;
   786 
   787 * system: tested support for MacOS X; should be able to get Isabelle +
   788 Proof General to work in a plain Terminal after installing Poly/ML
   789 (e.g. from the Isabelle distribution area) and GNU bash alone
   790 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   791 support requires further installations, e.g. from
   792 http://fink.sourceforge.net/);
   793 
   794 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   795 
   796 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   797 of 40 MB), cf. ML_OPTIONS;
   798 
   799 * system: Proof General keywords specification is now part of the
   800 Isabelle distribution (see etc/isar-keywords.el);
   801 
   802 * system: support for persistent Proof General sessions (refrain from
   803 outdating all loaded theories on startup); user may create writable
   804 logic images like this: ``isabelle -q HOL Test'';
   805 
   806 * system: smart selection of Isabelle process versus Isabelle
   807 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   808 run both "isabelle" and "Isabelle" even if file names are badly
   809 damaged (executable inspects the case of the first letter of its own
   810 name); added separate "isabelle-process" and "isabelle-interface";
   811 
   812 * system: refrain from any attempt at filtering input streams; no
   813 longer support ``8bit'' encoding of old isabelle font, instead proper
   814 iso-latin characters may now be used; the related isatools
   815 "symbolinput" and "nonascii" have disappeared as well;
   816 
   817 * system: removed old "xterm" interface (the print modes "xterm" and
   818 "xterm_color" are still available for direct use in a suitable
   819 terminal);
   820 
   821 
   822 
   823 New in Isabelle99-2 (February 2001)
   824 -----------------------------------
   825 
   826 *** Overview of INCOMPATIBILITIES ***
   827 
   828 * HOL: please note that theories in the Library and elsewhere often use the
   829 new-style (Isar) format; to refer to their theorems in an ML script you must
   830 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   831 
   832 * HOL: inductive package no longer splits induction rule aggressively,
   833 but only as far as specified by the introductions given; the old
   834 format may be recovered via ML function complete_split_rule or attribute
   835 'split_rule (complete)';
   836 
   837 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   838 gfp_Tarski to gfp_unfold;
   839 
   840 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   841 
   842 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   843 relation); infix "^^" has been renamed "``"; infix "``" has been
   844 renamed "`"; "univalent" has been renamed "single_valued";
   845 
   846 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   847 operation;
   848 
   849 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   850 
   851 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   852 
   853 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   854 consequence, it is no longer monotonic wrt. the local goal context
   855 (which is now passed through the inductive cases);
   856 
   857 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   858 \<gg> to \<ggreater>;
   859 
   860 
   861 *** Document preparation ***
   862 
   863 * \isabellestyle{NAME} selects version of Isabelle output (currently
   864 available: are "it" for near math-mode best-style output, "sl" for
   865 slanted text style, and "tt" for plain type-writer; if no
   866 \isabellestyle command is given, output is according to slanted
   867 type-writer);
   868 
   869 * support sub/super scripts (for single symbols only), input syntax is
   870 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   871 
   872 * some more standard symbols; see Appendix A of the system manual for
   873 the complete list of symbols defined in isabellesym.sty;
   874 
   875 * improved isabelle style files; more abstract symbol implementation
   876 (should now use \isamath{...} and \isatext{...} in custom symbol
   877 definitions);
   878 
   879 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   880 state; Note that presentation of goal states does not conform to
   881 actual human-readable proof documents.  Please do not include goal
   882 states into document output unless you really know what you are doing!
   883 
   884 * proper indentation of antiquoted output with proportional LaTeX
   885 fonts;
   886 
   887 * no_document ML operator temporarily disables LaTeX document
   888 generation;
   889 
   890 * isatool unsymbolize tunes sources for plain ASCII communication;
   891 
   892 
   893 *** Isar ***
   894 
   895 * Pure: Isar now suffers initial goal statements to contain unbound
   896 schematic variables (this does not conform to actual readable proof
   897 documents, due to unpredictable outcome and non-compositional proof
   898 checking); users who know what they are doing may use schematic goals
   899 for Prolog-style synthesis of proven results;
   900 
   901 * Pure: assumption method (an implicit finishing) now handles actual
   902 rules as well;
   903 
   904 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   905 initial goal, declare "that" only as Pure intro (only for single
   906 steps); the "that" rule assumption may now be involved in implicit
   907 finishing, thus ".." becomes a feasible for trivial obtains;
   908 
   909 * Pure: default proof step now includes 'intro_classes'; thus trivial
   910 instance proofs may be performed by "..";
   911 
   912 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   913 statements as well;
   914 
   915 * Pure: more robust selection of calculational rules;
   916 
   917 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   918 rule (as well as the assumption rule);
   919 
   920 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   921 lemmas, using the graph browser tool;
   922 
   923 * Pure: predict failure of "show" in interactive mode;
   924 
   925 * Pure: 'thms_containing' now takes actual terms as arguments;
   926 
   927 * HOL: improved method 'induct' --- now handles non-atomic goals
   928 (potential INCOMPATIBILITY); tuned error handling;
   929 
   930 * HOL: cases and induct rules now provide explicit hints about the
   931 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   932 any remaining facts are inserted into the goal verbatim;
   933 
   934 * HOL: local contexts (aka cases) may now contain term bindings as
   935 well; the 'cases' and 'induct' methods new provide a ?case binding for
   936 the result to be shown in each case;
   937 
   938 * HOL: added 'recdef_tc' command;
   939 
   940 * isatool convert assists in eliminating legacy ML scripts;
   941 
   942 
   943 *** HOL ***
   944 
   945 * HOL/Library: a collection of generic theories to be used together
   946 with main HOL; the theory loader path already includes this directory
   947 by default; the following existing theories have been moved here:
   948 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   949 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   950 
   951 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   952 modelling and verification task performed in Isabelle/HOL +
   953 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   954 
   955 * HOL/Algebra: special summation operator SUM no longer exists, it has
   956 been replaced by setsum; infix 'assoc' now has priority 50 (like
   957 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   958 'domain', this makes the theory consistent with mathematical
   959 literature;
   960 
   961 * HOL basics: added overloaded operations "inverse" and "divide"
   962 (infix "/"), syntax for generic "abs" operation, generic summation
   963 operator \<Sum>;
   964 
   965 * HOL/typedef: simplified package, provide more useful rules (see also
   966 HOL/subset.thy);
   967 
   968 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   969 now expressed as a proper nested rule (old-style tactic scripts may
   970 require atomize_strip_tac to cope with non-atomic premises);
   971 
   972 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   973 to "split_conv" (old name still available for compatibility);
   974 
   975 * HOL: improved concrete syntax for strings (e.g. allows translation
   976 rules with string literals);
   977 
   978 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   979  and Fleuriot's mechanization of analysis, including the transcendental
   980  functions for the reals;
   981 
   982 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   983 
   984 
   985 *** CTT ***
   986 
   987 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   988 "lam" is displayed as TWO lambda-symbols
   989 
   990 * CTT: theory Main now available, containing everything (that is, Bool
   991 and Arith);
   992 
   993 
   994 *** General ***
   995 
   996 * Pure: the Simplifier has been implemented properly as a derived rule
   997 outside of the actual kernel (at last!); the overall performance
   998 penalty in practical applications is about 50%, while reliability of
   999 the Isabelle inference kernel has been greatly improved;
  1000 
  1001 * print modes "brackets" and "no_brackets" control output of nested =>
  1002 (types) and ==> (props); the default behaviour is "brackets";
  1003 
  1004 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1005 as assumptions as well;
  1006 
  1007 * system: support Poly/ML 4.0;
  1008 
  1009 * system: isatool install handles KDE version 1 or 2;
  1010 
  1011 
  1012 
  1013 New in Isabelle99-1 (October 2000)
  1014 ----------------------------------
  1015 
  1016 *** Overview of INCOMPATIBILITIES ***
  1017 
  1018 * HOL: simplification of natural numbers is much changed; to partly
  1019 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1020 issue the following ML commands:
  1021 
  1022   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1023   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1024 
  1025 * HOL: simplification no longer dives into case-expressions; this is
  1026 controlled by "t.weak_case_cong" for each datatype t;
  1027 
  1028 * HOL: nat_less_induct renamed to less_induct;
  1029 
  1030 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1031 fixsome to patch .thy and .ML sources automatically;
  1032 
  1033   select_equality  -> some_equality
  1034   select_eq_Ex     -> some_eq_ex
  1035   selectI2EX       -> someI2_ex
  1036   selectI2         -> someI2
  1037   selectI          -> someI
  1038   select1_equality -> some1_equality
  1039   Eps_sym_eq       -> some_sym_eq_trivial
  1040   Eps_eq           -> some_eq_trivial
  1041 
  1042 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1043 
  1044 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1045 instead);
  1046 
  1047 * HOL: the recursion equations generated by 'recdef' are now called
  1048 f.simps instead of f.rules;
  1049 
  1050 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1051 
  1052 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1053 sometimes be needed;
  1054 
  1055 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1056 
  1057 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1058 
  1059 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1060 product is now "<*>" instead of "Times"; the lexicographic product is
  1061 now "<*lex*>" instead of "**";
  1062 
  1063 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1064 of main HOL, but was unused); better use HOL's datatype package;
  1065 
  1066 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1067 the old syntax may be recovered as follows:
  1068 
  1069   syntax (symbols)
  1070     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1071       (infixl "\\<oplus>" 100)
  1072 
  1073 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1074 
  1075 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1076 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1077 internally;
  1078 
  1079 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1080 changed from A/r to A//r;
  1081 
  1082 * ZF: new treatment of arithmetic (nat & int) may break some old
  1083 proofs;
  1084 
  1085 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1086 rulify -> rule_format, elimify -> elim_format, ...);
  1087 
  1088 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1089 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1090 should have to change intro!! to intro? only); replaced "delrule" by
  1091 "rule del";
  1092 
  1093 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1094 
  1095 * Provers: strengthened force_tac by using new first_best_tac;
  1096 
  1097 * LaTeX document preparation: several changes of isabelle.sty (see
  1098 lib/texinputs);
  1099 
  1100 
  1101 *** Document preparation ***
  1102 
  1103 * formal comments (text blocks etc.) in new-style theories may now
  1104 contain antiquotations of thm/prop/term/typ/text to be presented
  1105 according to latex print mode; concrete syntax is like this:
  1106 @{term[show_types] "f(x) = a + x"};
  1107 
  1108 * isatool mkdir provides easy setup of Isabelle session directories,
  1109 including proper document sources;
  1110 
  1111 * generated LaTeX sources are now deleted after successful run
  1112 (isatool document -c); may retain a copy somewhere else via -D option
  1113 of isatool usedir;
  1114 
  1115 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1116 style files, achieving self-contained LaTeX sources and simplifying
  1117 LaTeX debugging;
  1118 
  1119 * old-style theories now produce (crude) LaTeX output as well;
  1120 
  1121 * browser info session directories are now self-contained (may be put
  1122 on WWW server seperately); improved graphs of nested sessions; removed
  1123 graph for 'all sessions';
  1124 
  1125 * several improvements in isabelle style files; \isabellestyle{it}
  1126 produces fake math mode output; \isamarkupheader is now \section by
  1127 default; see lib/texinputs/isabelle.sty etc.;
  1128 
  1129 
  1130 *** Isar ***
  1131 
  1132 * Isar/Pure: local results and corresponding term bindings are now
  1133 subject to Hindley-Milner polymorphism (similar to ML); this
  1134 accommodates incremental type-inference very nicely;
  1135 
  1136 * Isar/Pure: new derived language element 'obtain' supports
  1137 generalized existence reasoning;
  1138 
  1139 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1140 support accumulation of results, without applying any rules yet;
  1141 useful to collect intermediate results without explicit name
  1142 references, and for use with transitivity rules with more than 2
  1143 premises;
  1144 
  1145 * Isar/Pure: scalable support for case-analysis type proofs: new
  1146 'case' language element refers to local contexts symbolically, as
  1147 produced by certain proof methods; internally, case names are attached
  1148 to theorems as "tags";
  1149 
  1150 * Isar/Pure: theory command 'hide' removes declarations from
  1151 class/type/const name spaces;
  1152 
  1153 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1154 indicate potential overloading;
  1155 
  1156 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1157 
  1158 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1159 "{a,b,c}" instead of {a,b,c};
  1160 
  1161 * Isar/Pure now provides its own version of intro/elim/dest
  1162 attributes; useful for building new logics, but beware of confusion
  1163 with the version in Provers/classical;
  1164 
  1165 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1166 case name 'antecedent';
  1167 
  1168 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1169 to the current context is now done automatically);
  1170 
  1171 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1172 for definining proof methods in ML;
  1173 
  1174 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1175 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1176 most cases, one should have to change intro!! to intro? only);
  1177 replaced "delrule" by "rule del";
  1178 
  1179 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1180 'symmetric' attribute (the latter supercedes [RS sym]);
  1181 
  1182 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1183 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1184 well (including splits);
  1185 
  1186 * Isar/Provers: Simplifier and Classical methods now support all kind
  1187 of modifiers used in the past, including 'cong', 'iff', etc.
  1188 
  1189 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1190 of Simplifier and Classical reasoner);
  1191 
  1192 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1193 now support named cases; major packages (inductive, datatype, primrec,
  1194 recdef) support case names and properly name parameters;
  1195 
  1196 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1197 monotonicity conditions are extracted to be proven at end of
  1198 calculations;
  1199 
  1200 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1201 method anyway;
  1202 
  1203 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1204 split_if split_if_asm; datatype package provides theorems foo.splits =
  1205 foo.split foo.split_asm for each datatype;
  1206 
  1207 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1208 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1209 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1210 use "(cases (simplified))" method in proper proof texts);
  1211 
  1212 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1213 
  1214 * Isar: names of theorems etc. may be natural numbers as well;
  1215 
  1216 * Isar: 'pr' command: optional arguments for goals_limit and
  1217 ProofContext.prems_limit; no longer prints theory contexts, but only
  1218 proof states;
  1219 
  1220 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1221 additional print modes to be specified; e.g. "pr(latex)" will print
  1222 proof state according to the Isabelle LaTeX style;
  1223 
  1224 * Isar: improved support for emulating tactic scripts, including proof
  1225 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1226 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1227 (for HOL datatypes);
  1228 
  1229 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1230 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1231 'proof method scripts' have to be in depth-first order;
  1232 
  1233 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1234 
  1235 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1236 should instead use individual commands for printing items
  1237 (print_commands, print_methods etc.);
  1238 
  1239 * Isar: added 'nothing' --- the empty list of theorems;
  1240 
  1241 
  1242 *** HOL ***
  1243 
  1244 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1245 corresponding virtual machine and a specification of its bytecode
  1246 verifier and a lightweight bytecode verifier, including proofs of
  1247 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1248 Cornelia Pusch (see also the homepage of project Bali at
  1249 http://isabelle.in.tum.de/Bali/);
  1250 
  1251 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1252 Clemens Ballarin;
  1253 
  1254 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1255 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1256 Rasmussen;
  1257 
  1258 * HOL/Lattice: fundamental concepts of lattice theory and order
  1259 structures, including duals, properties of bounds versus algebraic
  1260 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1261 Theorem for complete lattices etc.; may also serve as a demonstration
  1262 for abstract algebraic reasoning using axiomatic type classes, and
  1263 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1264 
  1265 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1266 von Oheimb;
  1267 
  1268 * HOL/IMPP: extension of IMP with local variables and mutually
  1269 recursive procedures, by David von Oheimb;
  1270 
  1271 * HOL/Lambda: converted into new-style theory and document;
  1272 
  1273 * HOL/ex/Multiquote: example of multiple nested quotations and
  1274 anti-quotations -- basically a generalized version of de-Bruijn
  1275 representation; very useful in avoiding lifting of operations;
  1276 
  1277 * HOL/record: added general record equality rule to simpset; fixed
  1278 select-update simplification procedure to handle extended records as
  1279 well; admit "r" as field name;
  1280 
  1281 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1282 other numeric types and also as the identity of groups, rings, etc.;
  1283 
  1284 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1285 Types nat and int belong to this axclass;
  1286 
  1287 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1288    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1289    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1290   two terms #m*u and #n*u are replaced by #(m+n)*u
  1291     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1292   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1293     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1294 
  1295 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1296 powerful prover for predicate logic but knows nothing of clasets; see
  1297 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1298 
  1299 * HOL: new version of "case_tac" subsumes both boolean case split and
  1300 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1301 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1302 
  1303 * HOL: simplification no longer dives into case-expressions: only the
  1304 selector expression is simplified, but not the remaining arms; to
  1305 enable full simplification of case-expressions for datatype t, you may
  1306 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1307 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1308 
  1309 * HOL/recdef: the recursion equations generated by 'recdef' for
  1310 function 'f' are now called f.simps instead of f.rules; if all
  1311 termination conditions are proved automatically, these simplification
  1312 rules are added to the simpset, as in primrec; rules may be named
  1313 individually as well, resulting in a separate list of theorems for
  1314 each equation;
  1315 
  1316 * HOL/While is a new theory that provides a while-combinator. It
  1317 permits the definition of tail-recursive functions without the
  1318 provision of a termination measure. The latter is necessary once the
  1319 invariant proof rule for while is applied.
  1320 
  1321 * HOL: new (overloaded) notation for the set of elements below/above
  1322 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1323 
  1324 * HOL: theorems impI, allI, ballI bound as "strip";
  1325 
  1326 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1327 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1328 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1329 
  1330 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1331 
  1332 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1333 main HOL, but was unused);
  1334 
  1335 * HOL: fewer consts declared as global (e.g. have to refer to
  1336 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1337 
  1338 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1339 in case of overlap with user translations (e.g. judgements over
  1340 tuples); (note that the underlying logical represenation is still
  1341 bogus);
  1342 
  1343 
  1344 *** ZF ***
  1345 
  1346 * ZF: simplification automatically cancels common terms in arithmetic
  1347 expressions over nat and int;
  1348 
  1349 * ZF: new treatment of nat to minimize type-checking: all operators
  1350 coerce their operands to a natural number using the function natify,
  1351 making the algebraic laws unconditional;
  1352 
  1353 * ZF: as above, for int: operators coerce their operands to an integer
  1354 using the function intify;
  1355 
  1356 * ZF: the integer library now contains many of the usual laws for the
  1357 orderings, including $<=, and monotonicity laws for $+ and $*;
  1358 
  1359 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1360 simplification;
  1361 
  1362 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1363 to the simplifier and classical reasoner simultaneously;
  1364 
  1365 
  1366 *** General ***
  1367 
  1368 * Provers: blast_tac now handles actual object-logic rules as
  1369 assumptions; note that auto_tac uses blast_tac internally as well;
  1370 
  1371 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1372 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1373 
  1374 * Provers: delrules now handles destruct rules as well (no longer need
  1375 explicit make_elim);
  1376 
  1377 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1378   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1379 use instead the strong form,
  1380   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1381 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1382 from destruct-rules;
  1383 
  1384 * Provers: Simplifier.easy_setup provides a fast path to basic
  1385 Simplifier setup for new object-logics;
  1386 
  1387 * Pure: AST translation rules no longer require constant head on LHS;
  1388 
  1389 * Pure: improved name spaces: ambiguous output is qualified; support
  1390 for hiding of names;
  1391 
  1392 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1393 XSYMBOL_HOME; no longer need to do manual configuration in most
  1394 situations;
  1395 
  1396 * system: compression of ML heaps images may now be controlled via -c
  1397 option of isabelle and isatool usedir (currently only observed by
  1398 Poly/ML);
  1399 
  1400 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1401 useful for remote X11);
  1402 
  1403 * system: provide TAGS file for Isabelle sources;
  1404 
  1405 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1406 order;
  1407 
  1408 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1409 timing flag supersedes proof_timing and Toplevel.trace;
  1410 
  1411 * ML: new combinators |>> and |>>> for incremental transformations
  1412 with secondary results (e.g. certain theory extensions):
  1413 
  1414 * ML: PureThy.add_defs gets additional argument to indicate potential
  1415 overloading (usually false);
  1416 
  1417 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1418 results;
  1419 
  1420 
  1421 
  1422 New in Isabelle99 (October 1999)
  1423 --------------------------------
  1424 
  1425 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1426 
  1427 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1428 are no longer simplified.  (This allows the simplifier to unfold recursive
  1429 functional programs.)  To restore the old behaviour, declare
  1430 
  1431     Delcongs [if_weak_cong];
  1432 
  1433 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1434 complement;
  1435 
  1436 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1437 
  1438 * HOL/datatype: mutual_induct_tac no longer exists --
  1439   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1440 
  1441 * HOL/typedef: fixed type inference for representing set; type
  1442 arguments now have to occur explicitly on the rhs as type constraints;
  1443 
  1444 * ZF: The con_defs part of an inductive definition may no longer refer
  1445 to constants declared in the same theory;
  1446 
  1447 * HOL, ZF: the function mk_cases, generated by the inductive
  1448 definition package, has lost an argument.  To simplify its result, it
  1449 uses the default simpset instead of a supplied list of theorems.
  1450 
  1451 * HOL/List: the constructors of type list are now Nil and Cons;
  1452 
  1453 * Simplifier: the type of the infix ML functions
  1454         setSSolver addSSolver setSolver addSolver
  1455 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1456 for packaging solvers. A solver is created via
  1457         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1458 where the string argument is only a comment.
  1459 
  1460 
  1461 *** Proof tools ***
  1462 
  1463 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1464 decision procedure for linear arithmetic. Currently it is used for
  1465 types `nat', `int', and `real' in HOL (see below); it can, should and
  1466 will be instantiated for other types and logics as well.
  1467 
  1468 * The simplifier now accepts rewrite rules with flexible heads, eg
  1469      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1470   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1471   matching.
  1472 
  1473 
  1474 *** General ***
  1475 
  1476 * New Isabelle/Isar subsystem provides an alternative to traditional
  1477 tactical theorem proving; together with the ProofGeneral/isar user
  1478 interface it offers an interactive environment for developing human
  1479 readable proof documents (Isar == Intelligible semi-automated
  1480 reasoning); for further information see isatool doc isar-ref,
  1481 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1482 
  1483 * improved and simplified presentation of theories: better HTML markup
  1484 (including colors), graph views in several sizes; isatool usedir now
  1485 provides a proper interface for user theories (via -P option); actual
  1486 document preparation based on (PDF)LaTeX is available as well (for
  1487 new-style theories only); see isatool doc system for more information;
  1488 
  1489 * native support for Proof General, both for classic Isabelle and
  1490 Isabelle/Isar;
  1491 
  1492 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1493 using the graph browser tool;
  1494 
  1495 * Isabelle manuals now also available as PDF;
  1496 
  1497 * theory loader rewritten from scratch (may not be fully
  1498 bug-compatible); old loadpath variable has been replaced by show_path,
  1499 add_path, del_path, reset_path functions; new operations such as
  1500 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1501 isatool doc ref);
  1502 
  1503 * improved isatool install: option -k creates KDE application icon,
  1504 option -p DIR installs standalone binaries;
  1505 
  1506 * added ML_PLATFORM setting (useful for cross-platform installations);
  1507 more robust handling of platform specific ML images for SML/NJ;
  1508 
  1509 * the settings environment is now statically scoped, i.e. it is never
  1510 created again in sub-processes invoked from isabelle, isatool, or
  1511 Isabelle;
  1512 
  1513 * path element specification '~~' refers to '$ISABELLE_HOME';
  1514 
  1515 * in locales, the "assumes" and "defines" parts may be omitted if
  1516 empty;
  1517 
  1518 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1519 long arrows);
  1520 
  1521 * new print_mode "HTML";
  1522 
  1523 * new flag show_tags controls display of tags of theorems (which are
  1524 basically just comments that may be attached by some tools);
  1525 
  1526 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1527 mode and goal output format:
  1528 
  1529 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1530 244c244
  1531 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1532 ---
  1533 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1534 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1535 181c181
  1536 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1537 ---
  1538 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1539 
  1540 * function bind_thms stores lists of theorems (cf. bind_thm);
  1541 
  1542 * new shorthand tactics ftac, eatac, datac, fatac;
  1543 
  1544 * qed (and friends) now accept "" as result name; in that case the
  1545 theorem is not stored, but proper checks and presentation of the
  1546 result still apply;
  1547 
  1548 * theorem database now also indexes constants "Trueprop", "all",
  1549 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1550 
  1551 
  1552 *** HOL ***
  1553 
  1554 ** HOL arithmetic **
  1555 
  1556 * There are now decision procedures for linear arithmetic over nat and
  1557 int:
  1558 
  1559 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1560 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1561 are treated as atomic; subformulae not involving type `nat' or `int'
  1562 are ignored; quantified subformulae are ignored unless they are
  1563 positive universal or negative existential. The tactic has to be
  1564 invoked by hand and can be a little bit slow. In particular, the
  1565 running time is exponential in the number of occurrences of `min' and
  1566 `max', and `-' on `nat'.
  1567 
  1568 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1569 (negated) (in)equalities among the premises and the conclusion into
  1570 account (i.e. no compound formulae) and does not know about `min' and
  1571 `max', and `-' on `nat'. It is fast and is used automatically by the
  1572 simplifier.
  1573 
  1574 NB: At the moment, these decision procedures do not cope with mixed
  1575 nat/int formulae where the two parts interact, such as `m < n ==>
  1576 int(m) < int(n)'.
  1577 
  1578 * HOL/Numeral provides a generic theory of numerals (encoded
  1579 efficiently as bit strings); setup for types nat/int/real is in place;
  1580 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1581 int, existing theories and proof scripts may require a few additional
  1582 type constraints;
  1583 
  1584 * integer division and remainder can now be performed on constant
  1585 arguments;
  1586 
  1587 * many properties of integer multiplication, division and remainder
  1588 are now available;
  1589 
  1590 * An interface to the Stanford Validity Checker (SVC) is available through the
  1591 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1592 are proved automatically.  SVC must be installed separately, and its results
  1593 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1594 invocation of the underlying oracle).  For SVC see
  1595   http://verify.stanford.edu/SVC
  1596 
  1597 * IsaMakefile: the HOL-Real target now builds an actual image;
  1598 
  1599 
  1600 ** HOL misc **
  1601 
  1602 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1603 (in Isabelle/Isar) -- by Gertrud Bauer;
  1604 
  1605 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1606 analysis for assembly languages with subtypes;
  1607 
  1608 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1609 -- avoids syntactic ambiguities and treats state, transition, and
  1610 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1611 changed syntax and (many) tactics;
  1612 
  1613 * HOL/inductive: Now also handles more general introduction rules such
  1614   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1615   theorems are now maintained within the theory (maintained via the
  1616   "mono" attribute);
  1617 
  1618 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1619   (using function types) such as
  1620 
  1621   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1622 
  1623 * HOL/record: record_simproc (part of the default simpset) takes care
  1624 of selectors applied to updated records; record_split_tac is no longer
  1625 part of the default claset; update_defs may now be removed from the
  1626 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1627 
  1628   claset_ref () := claset() addSWrapper record_split_wrapper;
  1629   Delsimprocs [record_simproc]
  1630 
  1631 * HOL/typedef: fixed type inference for representing set; type
  1632 arguments now have to occur explicitly on the rhs as type constraints;
  1633 
  1634 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1635 names rather than an ML expression;
  1636 
  1637 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1638 supplied later.  Program schemes can be defined, such as
  1639     "While B C s = (if B s then While B C (C s) else s)"
  1640 where the well-founded relation can be chosen after B and C have been given.
  1641 
  1642 * HOL/List: the constructors of type list are now Nil and Cons;
  1643 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1644 course, ML tools referring to List.list.op # etc. have to be adapted;
  1645 
  1646 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1647 disabled by default; run isabelle with option -m HOL to get back to
  1648 the original Gordon/HOL-style output;
  1649 
  1650 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1651 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1652 
  1653 * HOL basic syntax simplified (more orthogonal): all variants of
  1654 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1655 Eps operator is provided as well: "SOME x. P[x]";
  1656 
  1657 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1658 
  1659 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1660 thus available for user theories;
  1661 
  1662 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1663 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1664 time;
  1665 
  1666 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1667 several times and then mp;
  1668 
  1669 
  1670 *** LK ***
  1671 
  1672 * the notation <<...>> is now available as a notation for sequences of
  1673 formulas;
  1674 
  1675 * the simplifier is now installed
  1676 
  1677 * the axiom system has been generalized (thanks to Soren Heilmann)
  1678 
  1679 * the classical reasoner now has a default rule database
  1680 
  1681 
  1682 *** ZF ***
  1683 
  1684 * new primrec section allows primitive recursive functions to be given
  1685 directly (as in HOL) over datatypes and the natural numbers;
  1686 
  1687 * new tactics induct_tac and exhaust_tac for induction (or case
  1688 analysis) over datatypes and the natural numbers;
  1689 
  1690 * the datatype declaration of type T now defines the recursor T_rec;
  1691 
  1692 * simplification automatically does freeness reasoning for datatype
  1693 constructors;
  1694 
  1695 * automatic type-inference, with AddTCs command to insert new
  1696 type-checking rules;
  1697 
  1698 * datatype introduction rules are now added as Safe Introduction rules
  1699 to the claset;
  1700 
  1701 * the syntax "if P then x else y" is now available in addition to
  1702 if(P,x,y);
  1703 
  1704 
  1705 *** Internal programming interfaces ***
  1706 
  1707 * tuned simplifier trace output; new flag debug_simp;
  1708 
  1709 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1710 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1711 
  1712 * AxClass.axclass_tac lost the theory argument;
  1713 
  1714 * tuned current_goals_markers semantics: begin / end goal avoids
  1715 printing empty lines;
  1716 
  1717 * removed prs and prs_fn hook, which was broken because it did not
  1718 include \n in its semantics, forcing writeln to add one
  1719 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1720 string -> unit if you really want to output text without newline;
  1721 
  1722 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1723 plain output, interface builders may have to enable 'isabelle_font'
  1724 mode to get Isabelle font glyphs as before;
  1725 
  1726 * refined token_translation interface; INCOMPATIBILITY: output length
  1727 now of type real instead of int;
  1728 
  1729 * theory loader actions may be traced via new ThyInfo.add_hook
  1730 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1731 your own database of information attached to *whole* theories -- as
  1732 opposed to intra-theory data slots offered via TheoryDataFun;
  1733 
  1734 * proper handling of dangling sort hypotheses (at last!);
  1735 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1736 extra sort hypotheses that can be witnessed from the type signature;
  1737 the force_strip_shyps flag is gone, any remaining shyps are simply
  1738 left in the theorem (with a warning issued by strip_shyps_warning);
  1739 
  1740 
  1741 
  1742 New in Isabelle98-1 (October 1998)
  1743 ----------------------------------
  1744 
  1745 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1746 
  1747 * several changes of automated proof tools;
  1748 
  1749 * HOL: major changes to the inductive and datatype packages, including
  1750 some minor incompatibilities of theory syntax;
  1751 
  1752 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1753 called `inj_on';
  1754 
  1755 * HOL: removed duplicate thms in Arith:
  1756   less_imp_add_less  should be replaced by  trans_less_add1
  1757   le_imp_add_le      should be replaced by  trans_le_add1
  1758 
  1759 * HOL: unary minus is now overloaded (new type constraints may be
  1760 required);
  1761 
  1762 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1763 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1764 now taken as an integer constant.
  1765 
  1766 * Pure: ML function 'theory_of' renamed to 'theory';
  1767 
  1768 
  1769 *** Proof tools ***
  1770 
  1771 * Simplifier:
  1772   1. Asm_full_simp_tac is now more aggressive.
  1773      1. It will sometimes reorient premises if that increases their power to
  1774         simplify.
  1775      2. It does no longer proceed strictly from left to right but may also
  1776         rotate premises to achieve further simplification.
  1777      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1778      old Asm_full_simp_tac in that it does not rotate premises.
  1779   2. The simplifier now knows a little bit about nat-arithmetic.
  1780 
  1781 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1782 allows for selected deletion of wrappers, by introduction of names for
  1783 wrapper functionals.  This implies that addbefore, addSbefore,
  1784 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1785 and that adding two tactics with the same name overwrites the first
  1786 one (emitting a warning).
  1787   type wrapper = (int -> tactic) -> (int -> tactic)
  1788   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1789   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1790   delWrapper, delSWrapper: claset *  string            -> claset
  1791   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1792 
  1793 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1794 semantics; addbefore now affects only the unsafe part of step_tac
  1795 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1796 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1797 by Force_tac;
  1798 
  1799 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1800 compWrapper; added safe wrapper (and access functions for it);
  1801 
  1802 * HOL/split_all_tac is now much faster and fails if there is nothing
  1803 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1804 and the names of the automatically generated variables have changed.
  1805 split_all_tac has moved within claset() from unsafe wrappers to safe
  1806 wrappers, which means that !!-bound variables are split much more
  1807 aggressively, and safe_tac and clarify_tac now split such variables.
  1808 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1809 Note: the same holds for record_split_tac, which does the job of
  1810 split_all_tac for record fields.
  1811 
  1812 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1813 permanently to the default simpset using Addsplits just like
  1814 Addsimps. They can be removed via Delsplits just like
  1815 Delsimps. Lower-case versions are also available.
  1816 
  1817 * HOL/Simplifier: The rule split_if is now part of the default
  1818 simpset. This means that the simplifier will eliminate all occurrences
  1819 of if-then-else in the conclusion of a goal. To prevent this, you can
  1820 either remove split_if completely from the default simpset by
  1821 `Delsplits [split_if]' or remove it in a specific call of the
  1822 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1823 other case splitting rules to/from the default simpset: every datatype
  1824 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1825 t is the name of the datatype).
  1826 
  1827 * Classical reasoner / Simplifier combination: new force_tac (and
  1828 derivatives Force_tac, force) combines rewriting and classical
  1829 reasoning (and whatever other tools) similarly to auto_tac, but is
  1830 aimed to solve the given subgoal completely.
  1831 
  1832 
  1833 *** General ***
  1834 
  1835 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1836 and `goalw': the theory is no longer needed as an explicit argument -
  1837 the current theory context is used; assumptions are no longer returned
  1838 at the ML-level unless one of them starts with ==> or !!; it is
  1839 recommended to convert to these new commands using isatool fixgoal
  1840 (backup your sources first!);
  1841 
  1842 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1843 the current theory context, and 'theory' to lookup stored theories;
  1844 
  1845 * new theory section 'locale' for declaring constants, assumptions and
  1846 definitions that have local scope;
  1847 
  1848 * new theory section 'nonterminals' for purely syntactic types;
  1849 
  1850 * new theory section 'setup' for generic ML setup functions
  1851 (e.g. package initialization);
  1852 
  1853 * the distribution now includes Isabelle icons: see
  1854 lib/logo/isabelle-{small,tiny}.xpm;
  1855 
  1856 * isatool install - install binaries with absolute references to
  1857 ISABELLE_HOME/bin;
  1858 
  1859 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1860 
  1861 * print mode 'emacs' reserved for Isamode;
  1862 
  1863 * support multiple print (ast) translations per constant name;
  1864 
  1865 * theorems involving oracles are now printed with a suffixed [!];
  1866 
  1867 
  1868 *** HOL ***
  1869 
  1870 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1871 
  1872 * HOL/inductive package reorganized and improved: now supports mutual
  1873 definitions such as
  1874 
  1875   inductive EVEN ODD
  1876     intrs
  1877       null "0 : EVEN"
  1878       oddI "n : EVEN ==> Suc n : ODD"
  1879       evenI "n : ODD ==> Suc n : EVEN"
  1880 
  1881 new theorem list "elims" contains an elimination rule for each of the
  1882 recursive sets; inductive definitions now handle disjunctive premises
  1883 correctly (also ZF);
  1884 
  1885 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1886 "mutual_induct" no longer exists - the induction rule is always
  1887 contained in "induct";
  1888 
  1889 
  1890 * HOL/datatype package re-implemented and greatly improved: now
  1891 supports mutually recursive datatypes such as
  1892 
  1893   datatype
  1894     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1895             | SUM ('a aexp) ('a aexp)
  1896             | DIFF ('a aexp) ('a aexp)
  1897             | NUM 'a
  1898   and
  1899     'a bexp = LESS ('a aexp) ('a aexp)
  1900             | AND ('a bexp) ('a bexp)
  1901             | OR ('a bexp) ('a bexp)
  1902 
  1903 as well as indirectly recursive datatypes such as
  1904 
  1905   datatype
  1906     ('a, 'b) term = Var 'a
  1907                   | App 'b ((('a, 'b) term) list)
  1908 
  1909 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1910 induction on mutually / indirectly recursive datatypes.
  1911 
  1912 Primrec equations are now stored in theory and can be accessed via
  1913 <function_name>.simps.
  1914 
  1915 INCOMPATIBILITIES:
  1916 
  1917   - Theories using datatypes must now have theory Datatype as an
  1918     ancestor.
  1919   - The specific <typename>.induct_tac no longer exists - use the
  1920     generic induct_tac instead.
  1921   - natE has been renamed to nat.exhaust - use exhaust_tac
  1922     instead of res_inst_tac ... natE. Note that the variable
  1923     names in nat.exhaust differ from the names in natE, this
  1924     may cause some "fragile" proofs to fail.
  1925   - The theorems split_<typename>_case and split_<typename>_case_asm
  1926     have been renamed to <typename>.split and <typename>.split_asm.
  1927   - Since default sorts of type variables are now handled correctly,
  1928     some datatype definitions may have to be annotated with explicit
  1929     sort constraints.
  1930   - Primrec definitions no longer require function name and type
  1931     of recursive argument.
  1932 
  1933 Consider using isatool fixdatatype to adapt your theories and proof
  1934 scripts to the new package (backup your sources first!).
  1935 
  1936 
  1937 * HOL/record package: considerably improved implementation; now
  1938 includes concrete syntax for record types, terms, updates; theorems
  1939 for surjective pairing and splitting !!-bound record variables; proof
  1940 support is as follows:
  1941 
  1942   1) standard conversions (selectors or updates applied to record
  1943 constructor terms) are part of the standard simpset;
  1944 
  1945   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1946 made part of standard simpset and claset via addIffs;
  1947 
  1948   3) a tactic for record field splitting (record_split_tac) is part of
  1949 the standard claset (addSWrapper);
  1950 
  1951 To get a better idea about these rules you may retrieve them via
  1952 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1953 the name of your record type.
  1954 
  1955 The split tactic 3) conceptually simplifies by the following rule:
  1956 
  1957   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1958 
  1959 Thus any record variable that is bound by meta-all will automatically
  1960 blow up into some record constructor term, consequently the
  1961 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1962 solve record problems automatically.
  1963 
  1964 
  1965 * reorganized the main HOL image: HOL/Integ and String loaded by
  1966 default; theory Main includes everything;
  1967 
  1968 * automatic simplification of integer sums and comparisons, using cancellation;
  1969 
  1970 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1971 
  1972 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1973 
  1974 * many new identities for unions, intersections, set difference, etc.;
  1975 
  1976 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1977 called split_if, split_split, split_sum_case and split_nat_case (to go
  1978 with add/delsplits);
  1979 
  1980 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1981 (?x::unit) = (); this is made part of the default simpset, which COULD
  1982 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1983 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1984 unit_abs_eta_conv is added in order to counter the effect of
  1985 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1986 %u.f();
  1987 
  1988 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1989 makes more sense);
  1990 
  1991 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1992   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1993   disjointness reasoning but breaking a few old proofs.
  1994 
  1995 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1996 to 'converse' from 'inverse' (for compatibility with ZF and some
  1997 literature);
  1998 
  1999 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2000 the well-founded relation;
  2001 
  2002 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2003     Compl A.  The "Compl" syntax remains available as input syntax for this
  2004     release ONLY.
  2005 
  2006 * HOL/Update: new theory of function updates:
  2007     f(a:=b) == %x. if x=a then b else f x
  2008 may also be iterated as in f(a:=b,c:=d,...);
  2009 
  2010 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2011 
  2012 * HOL/List:
  2013   - new function list_update written xs[i:=v] that updates the i-th
  2014     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2015   - new function `upt' written [i..j(] which generates the list
  2016     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2017     bound write [i..j], which is a shorthand for [i..j+1(].
  2018   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2019 
  2020 * HOL/Arith:
  2021   - removed 'pred' (predecessor) function;
  2022   - generalized some theorems about n-1;
  2023   - many new laws about "div" and "mod";
  2024   - new laws about greatest common divisors (see theory ex/Primes);
  2025 
  2026 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2027 instead of "inverse";
  2028 
  2029 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2030   of the multiset ordering;
  2031 
  2032 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2033   (not included by default);
  2034 
  2035 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2036 
  2037 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2038   programs, i.e. different program variables may have different types.
  2039 
  2040 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2041   [previously, this check worked only if the rewrite rule was unconditional]
  2042   Now rew can involve either definitions or equalities (either == or =).
  2043 
  2044 
  2045 *** ZF ***
  2046 
  2047 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2048   only the theorems proved on ZF.ML;
  2049 
  2050 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2051   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2052   disjointness reasoning but breaking a few old proofs.
  2053 
  2054 * ZF/Update: new theory of function updates
  2055     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2056   may also be iterated as in f(a:=b,c:=d,...);
  2057 
  2058 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2059 
  2060 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2061   [previously, this check worked only if the rewrite rule was unconditional]
  2062   Now rew can involve either definitions or equalities (either == or =).
  2063 
  2064 * case_tac provided for compatibility with HOL
  2065     (like the old excluded_middle_tac, but with subgoals swapped)
  2066 
  2067 
  2068 *** Internal programming interfaces ***
  2069 
  2070 * Pure: several new basic modules made available for general use, see
  2071 also src/Pure/README;
  2072 
  2073 * improved the theory data mechanism to support encapsulation (data
  2074 kind name replaced by private Object.kind, acting as authorization
  2075 key); new type-safe user interface via functor TheoryDataFun; generic
  2076 print_data function becomes basically useless;
  2077 
  2078 * removed global_names compatibility flag -- all theory declarations
  2079 are qualified by default;
  2080 
  2081 * module Pure/Syntax now offers quote / antiquote translation
  2082 functions (useful for Hoare logic etc. with implicit dependencies);
  2083 see HOL/ex/Antiquote for an example use;
  2084 
  2085 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2086 cterm -> thm;
  2087 
  2088 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2089 subgoal;
  2090 
  2091 * Display.print_goals function moved to Locale.print_goals;
  2092 
  2093 * standard print function for goals supports current_goals_markers
  2094 variable for marking begin of proof, end of proof, start of goal; the
  2095 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2096 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2097 for example;
  2098 
  2099 
  2100 
  2101 New in Isabelle98 (January 1998)
  2102 --------------------------------
  2103 
  2104 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2105 
  2106 * changed lexical syntax of terms / types: dots made part of long
  2107 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2108 
  2109 * simpset (and claset) reference variable replaced by functions
  2110 simpset / simpset_ref;
  2111 
  2112 * no longer supports theory aliases (via merge) and non-trivial
  2113 implicit merge of thms' signatures;
  2114 
  2115 * most internal names of constants changed due to qualified names;
  2116 
  2117 * changed Pure/Sequence interface (see Pure/seq.ML);
  2118 
  2119 
  2120 *** General Changes ***
  2121 
  2122 * hierachically structured name spaces (for consts, types, axms, thms
  2123 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2124 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2125 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2126 long_names for fully qualified output names; NOTE: ML programs
  2127 (special tactics, packages etc.) referring to internal names may have
  2128 to be adapted to cope with fully qualified names; in case of severe
  2129 backward campatibility problems try setting 'global_names' at compile
  2130 time to have enrything declared within a flat name space; one may also
  2131 fine tune name declarations in theories via the 'global' and 'local'
  2132 section;
  2133 
  2134 * reimplemented the implicit simpset and claset using the new anytype
  2135 data filed in signatures; references simpset:simpset ref etc. are
  2136 replaced by functions simpset:unit->simpset and
  2137 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2138 to patch your ML files accordingly;
  2139 
  2140 * HTML output now includes theory graph data for display with Java
  2141 applet or isatool browser; data generated automatically via isatool
  2142 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2143 
  2144 * defs may now be conditional; improved rewrite_goals_tac to handle
  2145 conditional equations;
  2146 
  2147 * defs now admits additional type arguments, using TYPE('a) syntax;
  2148 
  2149 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2150 creates a new theory node; implicit merge of thms' signatures is
  2151 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2152 transfer:theory->thm->thm in (rare) cases;
  2153 
  2154 * improved handling of draft signatures / theories; draft thms (and
  2155 ctyps, cterms) are automatically promoted to real ones;
  2156 
  2157 * slightly changed interfaces for oracles: admit many per theory, named
  2158 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2159 
  2160 * print_goals: optional output of const types (set show_consts and
  2161 show_types);
  2162 
  2163 * improved output of warnings (###) and errors (***);
  2164 
  2165 * subgoal_tac displays a warning if the new subgoal has type variables;
  2166 
  2167 * removed old README and Makefiles;
  2168 
  2169 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2170 
  2171 * removed obsolete init_pps and init_database;
  2172 
  2173 * deleted the obsolete tactical STATE, which was declared by
  2174     fun STATE tacfun st = tacfun st st;
  2175 
  2176 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2177 (which abbreviates $HOME);
  2178 
  2179 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2180 use isatool fixseq to adapt your ML programs (this works for fully
  2181 qualified references to the Sequence structure only!);
  2182 
  2183 * use_thy no longer requires writable current directory; it always
  2184 reloads .ML *and* .thy file, if either one is out of date;
  2185 
  2186 
  2187 *** Classical Reasoner ***
  2188 
  2189 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2190 tactics that use classical reasoning to simplify a subgoal without
  2191 splitting it into several subgoals;
  2192 
  2193 * Safe_tac: like safe_tac but uses the default claset;
  2194 
  2195 
  2196 *** Simplifier ***
  2197 
  2198 * added simplification meta rules:
  2199     (asm_)(full_)simplify: simpset -> thm -> thm;
  2200 
  2201 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2202 logics (again);
  2203 
  2204 * added prems argument to simplification procedures;
  2205 
  2206 * HOL, FOL, ZF: added infix function `addsplits':
  2207   instead of `<simpset> setloop (split_tac <thms>)'
  2208   you can simply write `<simpset> addsplits <thms>'
  2209 
  2210 
  2211 *** Syntax ***
  2212 
  2213 * TYPE('a) syntax for type reflection terms;
  2214 
  2215 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2216 
  2217 * pretty printer: changed order of mixfix annotation preference (again!);
  2218 
  2219 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2220 
  2221 
  2222 *** HOL ***
  2223 
  2224 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2225   with `addloop' of the simplifier to faciliate case splitting in premises.
  2226 
  2227 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2228 
  2229 * HOL/Auth: new protocol proofs including some for the Internet
  2230   protocol TLS;
  2231 
  2232 * HOL/Map: new theory of `maps' a la VDM;
  2233 
  2234 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2235 cancelling out common nat summands from =, <, <= (in)equalities, or
  2236 differences; simplification procedures nat_cancel_factor for
  2237 cancelling common factor from =, <, <= (in)equalities over natural
  2238 sums; nat_cancel contains both kinds of procedures, it is installed by
  2239 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2240 
  2241 * HOL/simplifier: terms of the form
  2242   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2243   are rewritten to
  2244   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2245   and those of the form
  2246   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2247   are rewritten to
  2248   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2249 
  2250 * HOL/datatype
  2251   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2252 
  2253   P(t_case f1 ... fn x) =
  2254      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2255         ...
  2256        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2257      )
  2258 
  2259   and a theorem `split_t_case_asm' of the form
  2260 
  2261   P(t_case f1 ... fn x) =
  2262     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2263         ...
  2264        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2265      )
  2266   which can be added to a simpset via `addsplits'. The existing theorems
  2267   expand_list_case and expand_option_case have been renamed to
  2268   split_list_case and split_option_case.
  2269 
  2270 * HOL/Arithmetic:
  2271   - `pred n' is automatically converted to `n-1'.
  2272     Users are strongly encouraged not to use `pred' any longer,
  2273     because it will disappear altogether at some point.
  2274   - Users are strongly encouraged to write "0 < n" rather than
  2275     "n ~= 0". Theorems and proof tools have been modified towards this
  2276     `standard'.
  2277 
  2278 * HOL/Lists:
  2279   the function "set_of_list" has been renamed "set" (and its theorems too);
  2280   the function "nth" now takes its arguments in the reverse order and
  2281   has acquired the infix notation "!" as in "xs!n".
  2282 
  2283 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2284 
  2285 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2286   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2287 
  2288 * HOL/record: extensible records with schematic structural subtyping
  2289 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2290 still lacks various theorems and concrete record syntax;
  2291 
  2292 
  2293 *** HOLCF ***
  2294 
  2295 * removed "axioms" and "generated by" sections;
  2296 
  2297 * replaced "ops" section by extended "consts" section, which is capable of
  2298   handling the continuous function space "->" directly;
  2299 
  2300 * domain package:
  2301   . proves theorems immediately and stores them in the theory,
  2302   . creates hierachical name space,
  2303   . now uses normal mixfix annotations (instead of cinfix...),
  2304   . minor changes to some names and values (for consistency),
  2305   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2306   . separator between mutual domain defs: changed "," to "and",
  2307   . improved handling of sort constraints;  now they have to
  2308     appear on the left-hand side of the equations only;
  2309 
  2310 * fixed LAM <x,y,zs>.b syntax;
  2311 
  2312 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2313 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2314 
  2315 
  2316 *** FOL and ZF ***
  2317 
  2318 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2319   with `addloop' of the simplifier to faciliate case splitting in premises.
  2320 
  2321 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2322 in HOL, they strip ALL and --> from proved theorems;
  2323 
  2324 
  2325 
  2326 New in Isabelle94-8 (May 1997)
  2327 ------------------------------
  2328 
  2329 *** General Changes ***
  2330 
  2331 * new utilities to build / run / maintain Isabelle etc. (in parts
  2332 still somewhat experimental); old Makefiles etc. still functional;
  2333 
  2334 * new 'Isabelle System Manual';
  2335 
  2336 * INSTALL text, together with ./configure and ./build scripts;
  2337 
  2338 * reimplemented type inference for greater efficiency, better error
  2339 messages and clean internal interface;
  2340 
  2341 * prlim command for dealing with lots of subgoals (an easier way of
  2342 setting goals_limit);
  2343 
  2344 
  2345 *** Syntax ***
  2346 
  2347 * supports alternative (named) syntax tables (parser and pretty
  2348 printer); internal interface is provided by add_modesyntax(_i);
  2349 
  2350 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2351 be used in conjunction with the Isabelle symbol font; uses the
  2352 "symbols" syntax table;
  2353 
  2354 * added token_translation interface (may translate name tokens in
  2355 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2356 the current print_mode); IMPORTANT: user print translation functions
  2357 are responsible for marking newly introduced bounds
  2358 (Syntax.mark_boundT);
  2359 
  2360 * token translations for modes "xterm" and "xterm_color" that display
  2361 names in bold, underline etc. or colors (which requires a color
  2362 version of xterm);
  2363 
  2364 * infixes may now be declared with names independent of their syntax;
  2365 
  2366 * added typed_print_translation (like print_translation, but may
  2367 access type of constant);
  2368 
  2369 
  2370 *** Classical Reasoner ***
  2371 
  2372 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2373 some limitations.  Blast_tac...
  2374   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2375   + ignores elimination rules that don't have the correct format
  2376         (the conclusion MUST be a formula variable)
  2377   + ignores types, which can make HOL proofs fail
  2378   + rules must not require higher-order unification, e.g. apply_type in ZF
  2379     [message "Function Var's argument not a bound variable" relates to this]
  2380   + its proof strategy is more general but can actually be slower
  2381 
  2382 * substitution with equality assumptions no longer permutes other
  2383 assumptions;
  2384 
  2385 * minor changes in semantics of addafter (now called addaltern); renamed
  2386 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2387 (and access functions for it);
  2388 
  2389 * improved combination of classical reasoner and simplifier:
  2390   + functions for handling clasimpsets
  2391   + improvement of addss: now the simplifier is called _after_ the
  2392     safe steps.
  2393   + safe variant of addss called addSss: uses safe simplifications
  2394     _during_ the safe steps. It is more complete as it allows multiple
  2395     instantiations of unknowns (e.g. with slow_tac).
  2396 
  2397 *** Simplifier ***
  2398 
  2399 * added interface for simplification procedures (functions that
  2400 produce *proven* rewrite rules on the fly, depending on current
  2401 redex);
  2402 
  2403 * ordering on terms as parameter (used for ordered rewriting);
  2404 
  2405 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2406 
  2407 * the solver is now split into a safe and an unsafe part.
  2408 This should be invisible for the normal user, except that the
  2409 functions setsolver and addsolver have been renamed to setSolver and
  2410 addSolver; added safe_asm_full_simp_tac;
  2411 
  2412 
  2413 *** HOL ***
  2414 
  2415 * a generic induction tactic `induct_tac' which works for all datatypes and
  2416 also for type `nat';
  2417 
  2418 * a generic case distinction tactic `exhaust_tac' which works for all
  2419 datatypes and also for type `nat';
  2420 
  2421 * each datatype comes with a function `size';
  2422 
  2423 * patterns in case expressions allow tuple patterns as arguments to
  2424 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2425 
  2426 * primrec now also works with type nat;
  2427 
  2428 * recdef: a new declaration form, allows general recursive functions to be
  2429 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2430 
  2431 * the constant for negation has been renamed from "not" to "Not" to
  2432 harmonize with FOL, ZF, LK, etc.;
  2433 
  2434 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2435 infinite lists;
  2436 
  2437 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2438 
  2439 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2440 problems in commutative rings, using axiomatic type classes for + and *;
  2441 
  2442 * more examples in HOL/MiniML and HOL/Auth;
  2443 
  2444 * more default rewrite rules for quantifiers, union/intersection;
  2445 
  2446 * a new constant `arbitrary == @x.False';
  2447 
  2448 * HOLCF/IOA replaces old HOL/IOA;
  2449 
  2450 * HOLCF changes: derived all rules and arities
  2451   + axiomatic type classes instead of classes
  2452   + typedef instead of faking type definitions
  2453   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2454   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2455   + eliminated the types void, one, tr
  2456   + use unit lift and bool lift (with translations) instead of one and tr
  2457   + eliminated blift from Lift3.thy (use Def instead of blift)
  2458   all eliminated rules are derived as theorems --> no visible changes ;
  2459 
  2460 
  2461 *** ZF ***
  2462 
  2463 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2464 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2465 as ZF_cs addSIs [equalityI];
  2466 
  2467 
  2468 
  2469 New in Isabelle94-7 (November 96)
  2470 ---------------------------------
  2471 
  2472 * allowing negative levels (as offsets) in prlev and choplev;
  2473 
  2474 * super-linear speedup for large simplifications;
  2475 
  2476 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2477 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2478 FAIL); can suppress it using the command Delsimps (ex_simps @
  2479 all_simps); De Morgan laws are also now included, by default;
  2480 
  2481 * improved printing of ==>  :  ~:
  2482 
  2483 * new object-logic "Sequents" adds linear logic, while replacing LK
  2484 and Modal (thanks to Sara Kalvala);
  2485 
  2486 * HOL/Auth: correctness proofs for authentication protocols;
  2487 
  2488 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2489 examples on HOL/Auth);
  2490 
  2491 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2492 the rewriter and classical reasoner simultaneously;
  2493 
  2494 * function uresult no longer returns theorems in "standard" format;
  2495 regain previous version by: val uresult = standard o uresult;
  2496 
  2497 
  2498 
  2499 New in Isabelle94-6
  2500 -------------------
  2501 
  2502 * oracles -- these establish an interface between Isabelle and trusted
  2503 external reasoners, which may deliver results as theorems;
  2504 
  2505 * proof objects (in particular record all uses of oracles);
  2506 
  2507 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2508 
  2509 * "constdefs" section in theory files;
  2510 
  2511 * "primrec" section (HOL) no longer requires names;
  2512 
  2513 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2514 
  2515 
  2516 
  2517 New in Isabelle94-5
  2518 -------------------
  2519 
  2520 * reduced space requirements;
  2521 
  2522 * automatic HTML generation from theories;
  2523 
  2524 * theory files no longer require "..." (quotes) around most types;
  2525 
  2526 * new examples, including two proofs of the Church-Rosser theorem;
  2527 
  2528 * non-curried (1994) version of HOL is no longer distributed;
  2529 
  2530 
  2531 
  2532 New in Isabelle94-4
  2533 -------------------
  2534 
  2535 * greatly reduced space requirements;
  2536 
  2537 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2538 
  2539 * searchable theorem database (see the section "Retrieving theorems" on
  2540 page 8 of the Reference Manual);
  2541 
  2542 * new examples, including Grabczewski's monumental case study of the
  2543 Axiom of Choice;
  2544 
  2545 * The previous version of HOL renamed to Old_HOL;
  2546 
  2547 * The new version of HOL (previously called CHOL) uses a curried syntax
  2548 for functions.  Application looks like f a b instead of f(a,b);
  2549 
  2550 * Mutually recursive inductive definitions finally work in HOL;
  2551 
  2552 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2553 translates to the operator "split";
  2554 
  2555 
  2556 
  2557 New in Isabelle94-3
  2558 -------------------
  2559 
  2560 * new infix operator, addss, allowing the classical reasoner to
  2561 perform simplification at each step of its search.  Example:
  2562         fast_tac (cs addss ss)
  2563 
  2564 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2565 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2566 look like (a,b) instead of <a,b>;
  2567 
  2568 * PLEASE NOTE: CHOL will eventually replace HOL!
  2569 
  2570 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2571 It translates to the operator "split".  A new theory of integers is available;
  2572 
  2573 * In ZF, integer numerals now denote two's-complement binary integers.
  2574 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2575 
  2576 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2577 of the Axiom of Choice;
  2578 
  2579 
  2580 
  2581 New in Isabelle94-2
  2582 -------------------
  2583 
  2584 * Significantly faster resolution;
  2585 
  2586 * the different sections in a .thy file can now be mixed and repeated
  2587 freely;
  2588 
  2589 * Database of theorems for FOL, HOL and ZF.  New
  2590 commands including qed, qed_goal and bind_thm store theorems in the database.
  2591 
  2592 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2593 a given theory (thms_of), or find out what theory a theorem was proved in
  2594 (theory_of_thm);
  2595 
  2596 * Bugs fixed in the inductive definition and datatype packages;
  2597 
  2598 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2599 and HOL_dup_cs obsolete;
  2600 
  2601 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2602 have been removed;
  2603 
  2604 * Simpler definition of function space in ZF;
  2605 
  2606 * new results about cardinal and ordinal arithmetic in ZF;
  2607 
  2608 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2609 types;
  2610 
  2611 
  2612 $Id$