NEWS
author wenzelm
Thu Apr 15 20:32:33 2004 +0200 (2004-04-15)
changeset 14572 1408d312d3a9
parent 14561 c53396af770e
child 14602 e06ded775eca
permissions -rw-r--r--
tuned;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     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   PG and LaTeX, text between \<^bsup> and \<^esup> in superscript. The
    33   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   accepts all 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: It is now illegal to specify Theory.ML explicitly as a dependency
    46   in the files section of the theory Theory. (This is more of a diagnostic
    47   than a restriction, as the theory loader screws up if Theory.ML is manually
    48   loaded.)
    49 
    50 * Presentation: generated HTML now uses a CSS style sheet to make layout
    51   (somewhat) independet of content. It is copied from lib/html/isabelle.css. 
    52   It can be changed to alter the colors/layout of generated pages.
    53 
    54 
    55 *** Isar ***
    56 
    57 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
    58   cut_tac, subgoal_tac and thin_tac:
    59   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    60     locales are no longer forced to write Isar proof scripts.
    61     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    62     emulations.
    63   - INCOMPATIBILITY: names of variables to be instantiated may no
    64     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    65     This is consistent with the instantiation attribute "where".
    66 
    67 * Attributes "where" and "of":
    68   - Now take type variables of instantiated theorem into account when reading
    69     the instantiation string.  This fixes a bug that caused instantiated
    70     theorems to have too special types in some circumstances.
    71   - "where" permits explicit instantiations of type variables.
    72 
    73 * Calculation commands "moreover" and "also" no longer interfere with
    74   current facts ("this"), admitting arbitrary combinations with "then"
    75   and derived forms.
    76 
    77 * Locales:
    78   - Goal statements involving the context element "includes" no longer
    79     generate theorems with internal delta predicates (those ending on
    80     "_axioms") in the premise.
    81     Resolve particular premise with <locale>.intro to obtain old form.
    82   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    83     specification and "includes" elements in goal statement.
    84   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    85     [intro?] and [elim?] (respectively) by default.
    86   - Experimental command for instantiation of locales in proof contexts:
    87         instantiate <label>[<attrs>]: <loc>
    88     Instantiates locale <loc> and adds all its theorems to the current context
    89     taking into account their attributes.  Label and attrs are optional
    90     modifiers, like in theorem declarations.  If present, names of
    91     instantiated theorems are qualified with <label>, and the attributes
    92     <attrs> are applied after any attributes these theorems might have already.
    93       If the locale has assumptions, a chained fact of the form
    94     "<loc> t1 ... tn" is expected from which instantiations of the parameters
    95     are derived.  The command does not support old-style locales declared
    96     with "locale (open)".
    97       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
    98 
    99 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   100   (Isar) contexts.
   101 
   102 
   103 *** HOL ***
   104 
   105 * Simplifier:
   106   - Much improved handling of linear and partial orders.
   107     Reasoners for linear and partial orders are set up for type classes
   108     "linorder" and "order" respectively, and are added to the default simpset
   109     as solvers.  This means that the simplifier can build transitivity chains
   110     to solve goals from the assumptions.
   111   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   112     of blast or auto after simplification become unnecessary because the goal
   113     is solved by simplification already.
   114 
   115 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   116     all proved in axiomatic type classes for semirings, rings and fields.
   117 
   118 * Numerics:
   119   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   120     now formalized using the Ring_and_Field theory mentioned above. 
   121   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   122     than before, because now they are set up once in a generic manner.
   123   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   124     Look for the general versions in Ring_and_Field (and Power if they concern
   125     exponentiation).
   126 
   127 * Type "rat" of the rational numbers is now available in HOL-Complex.
   128 
   129 * Records:
   130   - Record types are now by default printed with their type abbreviation
   131     instead of the list of all field types. This can be configured via
   132     the reference "print_record_type_abbr".
   133   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   134     (not enabled by default).
   135   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   136     EX x. x = sel r to True (not enabled by default).
   137   - Tactic "record_split_simp_tac" to split and simplify records added.
   138  
   139 * 'specification' command added, allowing for definition by
   140   specification.  There is also an 'ax_specification' command that
   141   introduces the new constants axiomatically.
   142 
   143 * arith(_tac) is now able to generate counterexamples for reals as well.
   144 
   145 * HOL-Algebra: new locale "ring" for non-commutative rings.
   146 
   147 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   148  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   149 
   150 * Unions and Intersections:
   151   The x-symbol output syntax of UN and INT has been changed
   152   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   153   i.e. the index formulae has become a subscript, like in normal math.
   154   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   155   The subscript version is also accepted as input syntax.
   156 
   157 * Unions and Intersections over Intervals:
   158   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   159   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   160   like in normal math, and corresponding versions for < and for intersection.
   161 
   162 * ML: the legacy theory structures Int and List have been removed. They had
   163   conflicted with ML Basis Library structures having the same names.
   164 
   165 * 'refute' command added to search for (finite) countermodels.  Only works
   166   for a fragment of HOL.  The installation of an external SAT solver is
   167   highly recommended.  See "HOL/Refute.thy" for details.
   168 
   169 
   170 *** HOLCF ***
   171 
   172 * Streams now come with concatenation and are part of the HOLCF image
   173 
   174 
   175 
   176 New in Isabelle2003 (May 2003)
   177 --------------------------------
   178 
   179 *** General ***
   180 
   181 * Provers/simplifier:
   182 
   183   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   184     Assumptions are now subject to complete mutual simplification,
   185     not just from left to right. The simplifier now preserves
   186     the order of assumptions.
   187 
   188     Potential INCOMPATIBILITY:
   189 
   190     -- simp sometimes diverges where the old version did
   191        not, e.g. invoking simp on the goal
   192 
   193         [| P (f x); y = x; f x = f y |] ==> Q
   194 
   195        now gives rise to the infinite reduction sequence
   196 
   197         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   198 
   199        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   200        kind of problem.
   201 
   202     -- Tactics combining classical reasoner and simplification (such as auto)
   203        are also affected by this change, because many of them rely on
   204        simp. They may sometimes diverge as well or yield a different numbers
   205        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   206        in case of problems. Sometimes subsequent calls to the classical
   207        reasoner will fail because a preceeding call to the simplifier too
   208        eagerly simplified the goal, e.g. deleted redundant premises.
   209 
   210   - The simplifier trace now shows the names of the applied rewrite rules
   211 
   212   - You can limit the number of recursive invocations of the simplifier
   213     during conditional rewriting (where the simplifie tries to solve the
   214     conditions before applying the rewrite rule):
   215     ML "simp_depth_limit := n"
   216     where n is an integer. Thus you can force termination where previously
   217     the simplifier would diverge.
   218 
   219   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   220 
   221   - No longer aborts on failed congruence proof.  Instead, the
   222     congruence is ignored.
   223 
   224 * Pure: New generic framework for extracting programs from constructive
   225   proofs. See HOL/Extraction.thy for an example instantiation, as well
   226   as HOL/Extraction for some case studies.
   227 
   228 * Pure: The main goal of the proof state is no longer shown by default, only
   229 the subgoals. This behaviour is controlled by a new flag.
   230    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   231 (ML: Proof.show_main_goal).
   232 
   233 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   234 rules whose conclusion matches subgoal 1:
   235       PG menu: Isabelle/Isar -> Show me -> matching rules
   236 The rules are ordered by how closely they match the subgoal.
   237 In particular, rules that solve a subgoal outright are displayed first
   238 (or rather last, the way they are printed).
   239 (ML: ProofGeneral.print_intros())
   240 
   241 * Pure: New flag trace_unify_fail causes unification to print
   242 diagnostic information (PG: in trace buffer) when it fails. This is
   243 useful for figuring out why single step proofs like rule, erule or
   244 assumption failed.
   245 
   246 * Pure: Locale specifications now produce predicate definitions
   247 according to the body of text (covering assumptions modulo local
   248 definitions); predicate "loc_axioms" covers newly introduced text,
   249 while "loc" is cumulative wrt. all included locale expressions; the
   250 latter view is presented only on export into the global theory
   251 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   252 on the old view without predicates;
   253 
   254 * Pure: predefined locales "var" and "struct" are useful for sharing
   255 parameters (as in CASL, for example); just specify something like
   256 ``var x + var y + struct M'' as import;
   257 
   258 * Pure: improved thms_containing: proper indexing of facts instead of
   259 raw theorems; check validity of results wrt. current name space;
   260 include local facts of proof configuration (also covers active
   261 locales), cover fixed variables in index; may use "_" in term
   262 specification; an optional limit for the number of printed facts may
   263 be given (the default is 40);
   264 
   265 * Pure: disallow duplicate fact bindings within new-style theory files
   266 (batch-mode only);
   267 
   268 * Provers: improved induct method: assumptions introduced by case
   269 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   270 the goal statement); "foo" still refers to all facts collectively;
   271 
   272 * Provers: the function blast.overloaded has been removed: all constants
   273 are regarded as potentially overloaded, which improves robustness in exchange
   274 for slight decrease in efficiency;
   275 
   276 * Provers/linorder: New generic prover for transitivity reasoning over
   277 linear orders.  Note: this prover is not efficient!
   278 
   279 * Isar: preview of problems to finish 'show' now produce an error
   280 rather than just a warning (in interactive mode);
   281 
   282 
   283 *** HOL ***
   284 
   285 * arith(_tac)
   286 
   287  - Produces a counter example if it cannot prove a goal.
   288    Note that the counter example may be spurious if the goal is not a formula
   289    of quantifier-free linear arithmetic.
   290    In ProofGeneral the counter example appears in the trace buffer.
   291 
   292  - Knows about div k and mod k where k is a numeral of type nat or int.
   293 
   294  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   295    linear arithmetic fails. This takes account of quantifiers and divisibility.
   296    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   297 
   298 * simp's arithmetic capabilities have been enhanced a bit: it now
   299 takes ~= in premises into account (by performing a case split);
   300 
   301 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   302 are distributed over a sum of terms;
   303 
   304 * New tactic "trans_tac" and method "trans" instantiate
   305 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   306 "<=", "<" and "="). 
   307 
   308 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   309 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   310 
   311 * 'typedef' command has new option "open" to suppress the set
   312 definition;
   313 
   314 * functions Min and Max on finite sets have been introduced (theory
   315 Finite_Set);
   316 
   317 * attribute [symmetric] now works for relations as well; it turns
   318 (x,y) : R^-1 into (y,x) : R, and vice versa;
   319 
   320 * induct over a !!-quantified statement (say !!x1..xn):
   321   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   322 
   323 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   324 %x. None. Warning: empty_def now refers to the previously hidden definition
   325 of the empty set.
   326 
   327 * Algebra: formalization of classical algebra.  Intended as base for
   328 any algebraic development in Isabelle.  Currently covers group theory
   329 (up to Sylow's theorem) and ring theory (Universal Property of
   330 Univariate Polynomials).  Contributions welcome;
   331 
   332 * GroupTheory: deleted, since its material has been moved to Algebra;
   333 
   334 * Complex: new directory of the complex numbers with numeric constants, 
   335 nonstandard complex numbers, and some complex analysis, standard and 
   336 nonstandard (Jacques Fleuriot);
   337 
   338 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   339 
   340 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   341 Fleuriot);
   342 
   343 * Real/HahnBanach: updated and adapted to locales;
   344 
   345 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   346 Gray and Kramer);
   347 
   348 * UNITY: added the Meier-Sanders theory of progress sets;
   349 
   350 * MicroJava: bytecode verifier and lightweight bytecode verifier
   351 as abstract algorithms, instantiated to the JVM;
   352 
   353 * Bali: Java source language formalization. Type system, operational
   354 semantics, axiomatic semantics. Supported language features:
   355 classes, interfaces, objects,virtual methods, static methods,
   356 static/instance fields, arrays, access modifiers, definite
   357 assignment, exceptions.
   358 
   359 
   360 *** ZF ***
   361 
   362 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   363 universe, etc.);
   364 
   365 * Main ZF: virtually all theories converted to new-style format;
   366 
   367 
   368 *** ML ***
   369 
   370 * Pure: Tactic.prove provides sane interface for internal proofs;
   371 omits the infamous "standard" operation, so this is more appropriate
   372 than prove_goalw_cterm in many situations (e.g. in simprocs);
   373 
   374 * Pure: improved error reporting of simprocs;
   375 
   376 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   377 up simprocs;
   378 
   379 
   380 *** Document preparation ***
   381 
   382 * uses \par instead of \\ for line breaks in theory text. This may
   383 shift some page breaks in large documents. To get the old behaviour
   384 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   385 
   386 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   387 other packages
   388 
   389 * \<euro> now needs package babel/greek instead of marvosym (which
   390 broke \Rightarrow)
   391 
   392 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   393 textcomp package)
   394 
   395 
   396 
   397 New in Isabelle2002 (March 2002)
   398 --------------------------------
   399 
   400 *** Document preparation ***
   401 
   402 * greatly simplified document preparation setup, including more
   403 graceful interpretation of isatool usedir -i/-d/-D options, and more
   404 instructive isatool mkdir; users should basically be able to get
   405 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   406 users may run a separate document processing stage manually like this:
   407 "isatool usedir -D output HOL Test && isatool document Test/output";
   408 
   409 * theory dependency graph may now be incorporated into documents;
   410 isatool usedir -g true will produce session_graph.eps/.pdf for use
   411 with \includegraphics of LaTeX;
   412 
   413 * proper spacing of consecutive markup elements, especially text
   414 blocks after section headings;
   415 
   416 * support bold style (for single symbols only), input syntax is like
   417 this: "\<^bold>\<alpha>" or "\<^bold>A";
   418 
   419 * \<bullet> is now output as bold \cdot by default, which looks much
   420 better in printed text;
   421 
   422 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   423 note that these symbols are currently unavailable in Proof General /
   424 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   425 
   426 * isatool latex no longer depends on changed TEXINPUTS, instead
   427 isatool document copies the Isabelle style files to the target
   428 location;
   429 
   430 
   431 *** Isar ***
   432 
   433 * Pure/Provers: improved proof by cases and induction;
   434   - 'case' command admits impromptu naming of parameters (such as
   435     "case (Suc n)");
   436   - 'induct' method divinates rule instantiation from the inductive
   437     claim; no longer requires excessive ?P bindings for proper
   438     instantiation of cases;
   439   - 'induct' method properly enumerates all possibilities of set/type
   440     rules; as a consequence facts may be also passed through *type*
   441     rules without further ado;
   442   - 'induct' method now derives symbolic cases from the *rulified*
   443     rule (before it used to rulify cases stemming from the internal
   444     atomized version); this means that the context of a non-atomic
   445     statement becomes is included in the hypothesis, avoiding the
   446     slightly cumbersome show "PROP ?case" form;
   447   - 'induct' may now use elim-style induction rules without chaining
   448     facts, using ``missing'' premises from the goal state; this allows
   449     rules stemming from inductive sets to be applied in unstructured
   450     scripts, while still benefitting from proper handling of non-atomic
   451     statements; NB: major inductive premises need to be put first, all
   452     the rest of the goal is passed through the induction;
   453   - 'induct' proper support for mutual induction involving non-atomic
   454     rule statements (uses the new concept of simultaneous goals, see
   455     below);
   456   - append all possible rule selections, but only use the first
   457     success (no backtracking);
   458   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   459   - undeclared rule case names default to numbers 1, 2, 3, ...;
   460   - added 'print_induct_rules' (covered by help item in recent Proof
   461     General versions);
   462   - moved induct/cases attributes to Pure, methods to Provers;
   463   - generic method setup instantiated for FOL and HOL;
   464 
   465 * Pure: support multiple simultaneous goal statements, for example
   466 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   467 meta-level mechanism, this acts as if several individual goals had
   468 been stated separately; in particular common proof methods need to be
   469 repeated in order to cover all claims; note that a single elimination
   470 step is *not* sufficient to establish the two conjunctions, so this
   471 fails:
   472 
   473   assume "A & B" then have A and B ..   (*".." fails*)
   474 
   475 better use "obtain" in situations as above; alternative refer to
   476 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   477 
   478 * Pure: proper integration with ``locales''; unlike the original
   479 version by Florian Kammüller, Isar locales package high-level proof
   480 contexts rather than raw logical ones (e.g. we admit to include
   481 attributes everywhere); operations on locales include merge and
   482 rename; support for implicit arguments (``structures''); simultaneous
   483 type-inference over imports and text; see also HOL/ex/Locales.thy for
   484 some examples;
   485 
   486 * Pure: the following commands have been ``localized'', supporting a
   487 target locale specification "(in name)": 'lemma', 'theorem',
   488 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   489 stored both within the locale and at the theory level (exported and
   490 qualified by the locale name);
   491 
   492 * Pure: theory goals may now be specified in ``long'' form, with
   493 ad-hoc contexts consisting of arbitrary locale elements. for example
   494 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   495 definitions may be given, too); the result is a meta-level rule with
   496 the context elements being discharged in the obvious way;
   497 
   498 * Pure: new proof command 'using' allows to augment currently used
   499 facts after a goal statement ('using' is syntactically analogous to
   500 'apply', but acts on the goal's facts only); this allows chained facts
   501 to be separated into parts given before and after a claim, as in
   502 ``from a and b have C using d and e <proof>'';
   503 
   504 * Pure: renamed "antecedent" case to "rule_context";
   505 
   506 * Pure: new 'judgment' command records explicit information about the
   507 object-logic embedding (used by several tools internally); no longer
   508 use hard-wired "Trueprop";
   509 
   510 * Pure: added 'corollary' command;
   511 
   512 * Pure: fixed 'token_translation' command;
   513 
   514 * Pure: removed obsolete 'exported' attribute;
   515 
   516 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   517 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   518 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   519 
   520 * Pure: method 'atomize' presents local goal premises as object-level
   521 statements (atomic meta-level propositions); setup controlled via
   522 rewrite rules declarations of 'atomize' attribute; example
   523 application: 'induct' method with proper rule statements in improper
   524 proof *scripts*;
   525 
   526 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   527 now consider the syntactic context of assumptions, giving a better
   528 chance to get type-inference of the arguments right (this is
   529 especially important for locales);
   530 
   531 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   532 mode;
   533 
   534 * Pure/obtain: the formal conclusion "thesis", being marked as
   535 ``internal'', may no longer be reference directly in the text;
   536 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   537 situations;
   538 
   539 * Pure: generic 'sym' attribute which declares a rule both as pure
   540 'elim?' and for the 'symmetric' operation;
   541 
   542 * Pure: marginal comments ``--'' may now occur just anywhere in the
   543 text; the fixed correlation with particular command syntax has been
   544 discontinued;
   545 
   546 * Pure: new method 'rules' is particularly well-suited for proof
   547 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   548 but often produces more compact proof terms with less detours;
   549 
   550 * Pure/Provers/classical: simplified integration with pure rule
   551 attributes and methods; the classical "intro?/elim?/dest?"
   552 declarations coincide with the pure ones; the "rule" method no longer
   553 includes classically swapped intros; "intro" and "elim" methods no
   554 longer pick rules from the context; also got rid of ML declarations
   555 AddXIs/AddXEs/AddXDs; all of this has some potential for
   556 INCOMPATIBILITY;
   557 
   558 * Provers/classical: attribute 'swapped' produces classical inversions
   559 of introduction rules;
   560 
   561 * Provers/simplifier: 'simplified' attribute may refer to explicit
   562 rules instead of full simplifier context; 'iff' attribute handles
   563 conditional rules;
   564 
   565 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   566 
   567 * HOL: 'recdef' now fails on unfinished automated proofs, use
   568 "(permissive)" option to recover old behavior;
   569 
   570 * HOL: 'inductive' no longer features separate (collective) attributes
   571 for 'intros' (was found too confusing);
   572 
   573 * HOL: properly declared induction rules less_induct and
   574 wf_induct_rule;
   575 
   576 
   577 *** HOL ***
   578 
   579 * HOL: moved over to sane numeral syntax; the new policy is as
   580 follows:
   581 
   582   - 0 and 1 are polymorphic constants, which are defined on any
   583   numeric type (nat, int, real etc.);
   584 
   585   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   586   binary representation internally;
   587 
   588   - type nat has special constructor Suc, and generally prefers Suc 0
   589   over 1::nat and Suc (Suc 0) over 2::nat;
   590 
   591 This change may cause significant problems of INCOMPATIBILITY; here
   592 are some hints on converting existing sources:
   593 
   594   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   595   entities, so expressions involving "-" (unary or binary minus) need
   596   to be spaced properly;
   597 
   598   - existing occurrences of "1" may need to be constraint "1::nat" or
   599   even replaced by Suc 0; similar for old "2";
   600 
   601   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   602 
   603   - remove all special provisions on numerals in proofs;
   604 
   605 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   606 representation (depends on bin_arith_simps in the default context);
   607 
   608 * HOL: symbolic syntax for x^2 (numeral 2);
   609 
   610 * HOL: the class of all HOL types is now called "type" rather than
   611 "term"; INCOMPATIBILITY, need to adapt references to this type class
   612 in axclass/classes, instance/arities, and (usually rare) occurrences
   613 in typings (of consts etc.); internally the class is called
   614 "HOL.type", ML programs should refer to HOLogic.typeS;
   615 
   616 * HOL/record package improvements:
   617   - new derived operations "fields" to build a partial record section,
   618     "extend" to promote a fixed record to a record scheme, and
   619     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   620     declared as simp by default;
   621   - shared operations ("more", "fields", etc.) now need to be always
   622     qualified) --- potential INCOMPATIBILITY;
   623   - removed "make_scheme" operations (use "make" with "extend") --
   624     INCOMPATIBILITY;
   625   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   626   - provides cases/induct rules for use with corresponding Isar
   627     methods (for concrete records, record schemes, concrete more
   628     parts, and schematic more parts -- in that order);
   629   - internal definitions directly based on a light-weight abstract
   630     theory of product types over typedef rather than datatype;
   631 
   632 * HOL: generic code generator for generating executable ML code from
   633 specifications; specific support for HOL constructs such as inductive
   634 datatypes and sets, as well as recursive functions; can be invoked
   635 via 'generate_code' theory section;
   636 
   637 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   638 
   639 * HOL: consolidated and renamed several theories.  In particular:
   640 	Ord.thy has been absorbed into HOL.thy
   641 	String.thy has been absorbed into List.thy
   642  
   643 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   644 (beware of argument permutation!);
   645 
   646 * HOL: linorder_less_split superseded by linorder_cases;
   647 
   648 * HOL/List: "nodups" renamed to "distinct";
   649 
   650 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   651 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   652   - Ex_def has changed, now need to use some_eq_ex
   653 
   654 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   655 in this (rare) case use:
   656 
   657   delSWrapper "split_all_tac"
   658   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   659 
   660 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   661 MAY FAIL;
   662 
   663 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   664 Isabelle's type classes, ^ on functions and relations has too general
   665 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   666 necessary to attach explicit type constraints;
   667 
   668 * HOL/Relation: the prefix name of the infix "O" has been changed from
   669 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   670 renamed accordingly (eg "compI" -> "rel_compI").
   671 
   672 * HOL: syntax translations now work properly with numerals and records
   673 expressions;
   674 
   675 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   676 of "lam" -- INCOMPATIBILITY;
   677 
   678 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   679 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   680 renamed "Product_Type.unit";
   681 
   682 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   683 
   684 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   685 the "cases" method);
   686 
   687 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   688 Florian Kammüller);
   689 
   690 * HOL/IMP: updated and converted to new-style theory format; several
   691 parts turned into readable document, with proper Isar proof texts and
   692 some explanations (by Gerwin Klein);
   693 
   694 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   695 
   696 * HOL-Hyperreal is now a logic image;
   697 
   698 
   699 *** HOLCF ***
   700 
   701 * Isar: consts/constdefs supports mixfix syntax for continuous
   702 operations;
   703 
   704 * Isar: domain package adapted to new-style theory format, e.g. see
   705 HOLCF/ex/Dnat.thy;
   706 
   707 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   708 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   709 lift.induct_tac, always use UU instead of Undef;
   710 
   711 * HOLCF/IMP: updated and converted to new-style theory;
   712 
   713 
   714 *** ZF ***
   715 
   716 * Isar: proper integration of logic-specific tools and packages,
   717 including theory commands '(co)inductive', '(co)datatype',
   718 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   719 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   720 
   721 * theory Main no longer includes AC; for the Axiom of Choice, base
   722 your theory on Main_ZFC;
   723 
   724 * the integer library now covers quotients and remainders, with many
   725 laws relating division to addition, multiplication, etc.;
   726 
   727 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   728 typeless version of the formalism;
   729 
   730 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   731 format;
   732 
   733 * ZF/Induct: new directory for examples of inductive definitions,
   734 including theory Multiset for multiset orderings; converted to
   735 new-style theory format;
   736 
   737 * ZF: many new theorems about lists, ordinals, etc.;
   738 
   739 
   740 *** General ***
   741 
   742 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   743 variable proof controls level of detail: 0 = no proofs (only oracle
   744 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   745 also ref manual for further ML interfaces;
   746 
   747 * Pure/axclass: removed obsolete ML interface
   748 goal_subclass/goal_arity;
   749 
   750 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   751 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   752 separate tokens, so expressions involving minus need to be spaced
   753 properly;
   754 
   755 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   756 rather than "infixl" or "infixr";
   757 
   758 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   759 sort constraint specifications in type inference; e.g. "x::_::foo"
   760 ensures that the type of "x" is of sort "foo" (but not necessarily a
   761 type variable);
   762 
   763 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   764 control output of nested => (types); the default behavior is
   765 "type_brackets";
   766 
   767 * Pure/syntax: builtin parse translation for "_constify" turns valued
   768 tokens into AST constants;
   769 
   770 * Pure/syntax: prefer later declarations of translations and print
   771 translation functions; potential INCOMPATIBILITY: need to reverse
   772 multiple declarations for same syntax element constant;
   773 
   774 * Pure/show_hyps reset by default (in accordance to existing Isar
   775 practice);
   776 
   777 * Provers/classical: renamed addaltern to addafter, addSaltern to
   778 addSafter;
   779 
   780 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   781 as well;
   782 
   783 * system: tested support for MacOS X; should be able to get Isabelle +
   784 Proof General to work in a plain Terminal after installing Poly/ML
   785 (e.g. from the Isabelle distribution area) and GNU bash alone
   786 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   787 support requires further installations, e.g. from
   788 http://fink.sourceforge.net/);
   789 
   790 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   791 
   792 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   793 of 40 MB), cf. ML_OPTIONS;
   794 
   795 * system: Proof General keywords specification is now part of the
   796 Isabelle distribution (see etc/isar-keywords.el);
   797 
   798 * system: support for persistent Proof General sessions (refrain from
   799 outdating all loaded theories on startup); user may create writable
   800 logic images like this: ``isabelle -q HOL Test'';
   801 
   802 * system: smart selection of Isabelle process versus Isabelle
   803 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   804 run both "isabelle" and "Isabelle" even if file names are badly
   805 damaged (executable inspects the case of the first letter of its own
   806 name); added separate "isabelle-process" and "isabelle-interface";
   807 
   808 * system: refrain from any attempt at filtering input streams; no
   809 longer support ``8bit'' encoding of old isabelle font, instead proper
   810 iso-latin characters may now be used; the related isatools
   811 "symbolinput" and "nonascii" have disappeared as well;
   812 
   813 * system: removed old "xterm" interface (the print modes "xterm" and
   814 "xterm_color" are still available for direct use in a suitable
   815 terminal);
   816 
   817 
   818 
   819 New in Isabelle99-2 (February 2001)
   820 -----------------------------------
   821 
   822 *** Overview of INCOMPATIBILITIES ***
   823 
   824 * HOL: please note that theories in the Library and elsewhere often use the
   825 new-style (Isar) format; to refer to their theorems in an ML script you must
   826 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   827 
   828 * HOL: inductive package no longer splits induction rule aggressively,
   829 but only as far as specified by the introductions given; the old
   830 format may be recovered via ML function complete_split_rule or attribute
   831 'split_rule (complete)';
   832 
   833 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   834 gfp_Tarski to gfp_unfold;
   835 
   836 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   837 
   838 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   839 relation); infix "^^" has been renamed "``"; infix "``" has been
   840 renamed "`"; "univalent" has been renamed "single_valued";
   841 
   842 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   843 operation;
   844 
   845 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   846 
   847 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   848 
   849 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   850 consequence, it is no longer monotonic wrt. the local goal context
   851 (which is now passed through the inductive cases);
   852 
   853 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   854 \<gg> to \<ggreater>;
   855 
   856 
   857 *** Document preparation ***
   858 
   859 * \isabellestyle{NAME} selects version of Isabelle output (currently
   860 available: are "it" for near math-mode best-style output, "sl" for
   861 slanted text style, and "tt" for plain type-writer; if no
   862 \isabellestyle command is given, output is according to slanted
   863 type-writer);
   864 
   865 * support sub/super scripts (for single symbols only), input syntax is
   866 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   867 
   868 * some more standard symbols; see Appendix A of the system manual for
   869 the complete list of symbols defined in isabellesym.sty;
   870 
   871 * improved isabelle style files; more abstract symbol implementation
   872 (should now use \isamath{...} and \isatext{...} in custom symbol
   873 definitions);
   874 
   875 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   876 state; Note that presentation of goal states does not conform to
   877 actual human-readable proof documents.  Please do not include goal
   878 states into document output unless you really know what you are doing!
   879 
   880 * proper indentation of antiquoted output with proportional LaTeX
   881 fonts;
   882 
   883 * no_document ML operator temporarily disables LaTeX document
   884 generation;
   885 
   886 * isatool unsymbolize tunes sources for plain ASCII communication;
   887 
   888 
   889 *** Isar ***
   890 
   891 * Pure: Isar now suffers initial goal statements to contain unbound
   892 schematic variables (this does not conform to actual readable proof
   893 documents, due to unpredictable outcome and non-compositional proof
   894 checking); users who know what they are doing may use schematic goals
   895 for Prolog-style synthesis of proven results;
   896 
   897 * Pure: assumption method (an implicit finishing) now handles actual
   898 rules as well;
   899 
   900 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   901 initial goal, declare "that" only as Pure intro (only for single
   902 steps); the "that" rule assumption may now be involved in implicit
   903 finishing, thus ".." becomes a feasible for trivial obtains;
   904 
   905 * Pure: default proof step now includes 'intro_classes'; thus trivial
   906 instance proofs may be performed by "..";
   907 
   908 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   909 statements as well;
   910 
   911 * Pure: more robust selection of calculational rules;
   912 
   913 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   914 rule (as well as the assumption rule);
   915 
   916 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   917 lemmas, using the graph browser tool;
   918 
   919 * Pure: predict failure of "show" in interactive mode;
   920 
   921 * Pure: 'thms_containing' now takes actual terms as arguments;
   922 
   923 * HOL: improved method 'induct' --- now handles non-atomic goals
   924 (potential INCOMPATIBILITY); tuned error handling;
   925 
   926 * HOL: cases and induct rules now provide explicit hints about the
   927 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   928 any remaining facts are inserted into the goal verbatim;
   929 
   930 * HOL: local contexts (aka cases) may now contain term bindings as
   931 well; the 'cases' and 'induct' methods new provide a ?case binding for
   932 the result to be shown in each case;
   933 
   934 * HOL: added 'recdef_tc' command;
   935 
   936 * isatool convert assists in eliminating legacy ML scripts;
   937 
   938 
   939 *** HOL ***
   940 
   941 * HOL/Library: a collection of generic theories to be used together
   942 with main HOL; the theory loader path already includes this directory
   943 by default; the following existing theories have been moved here:
   944 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   945 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   946 
   947 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   948 modelling and verification task performed in Isabelle/HOL +
   949 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   950 
   951 * HOL/Algebra: special summation operator SUM no longer exists, it has
   952 been replaced by setsum; infix 'assoc' now has priority 50 (like
   953 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   954 'domain', this makes the theory consistent with mathematical
   955 literature;
   956 
   957 * HOL basics: added overloaded operations "inverse" and "divide"
   958 (infix "/"), syntax for generic "abs" operation, generic summation
   959 operator \<Sum>;
   960 
   961 * HOL/typedef: simplified package, provide more useful rules (see also
   962 HOL/subset.thy);
   963 
   964 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   965 now expressed as a proper nested rule (old-style tactic scripts may
   966 require atomize_strip_tac to cope with non-atomic premises);
   967 
   968 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   969 to "split_conv" (old name still available for compatibility);
   970 
   971 * HOL: improved concrete syntax for strings (e.g. allows translation
   972 rules with string literals);
   973 
   974 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   975  and Fleuriot's mechanization of analysis, including the transcendental
   976  functions for the reals;
   977 
   978 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   979 
   980 
   981 *** CTT ***
   982 
   983 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   984 "lam" is displayed as TWO lambda-symbols
   985 
   986 * CTT: theory Main now available, containing everything (that is, Bool
   987 and Arith);
   988 
   989 
   990 *** General ***
   991 
   992 * Pure: the Simplifier has been implemented properly as a derived rule
   993 outside of the actual kernel (at last!); the overall performance
   994 penalty in practical applications is about 50%, while reliability of
   995 the Isabelle inference kernel has been greatly improved;
   996 
   997 * print modes "brackets" and "no_brackets" control output of nested =>
   998 (types) and ==> (props); the default behaviour is "brackets";
   999 
  1000 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1001 as assumptions as well;
  1002 
  1003 * system: support Poly/ML 4.0;
  1004 
  1005 * system: isatool install handles KDE version 1 or 2;
  1006 
  1007 
  1008 
  1009 New in Isabelle99-1 (October 2000)
  1010 ----------------------------------
  1011 
  1012 *** Overview of INCOMPATIBILITIES ***
  1013 
  1014 * HOL: simplification of natural numbers is much changed; to partly
  1015 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1016 issue the following ML commands:
  1017 
  1018   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1019   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1020 
  1021 * HOL: simplification no longer dives into case-expressions; this is
  1022 controlled by "t.weak_case_cong" for each datatype t;
  1023 
  1024 * HOL: nat_less_induct renamed to less_induct;
  1025 
  1026 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1027 fixsome to patch .thy and .ML sources automatically;
  1028 
  1029   select_equality  -> some_equality
  1030   select_eq_Ex     -> some_eq_ex
  1031   selectI2EX       -> someI2_ex
  1032   selectI2         -> someI2
  1033   selectI          -> someI
  1034   select1_equality -> some1_equality
  1035   Eps_sym_eq       -> some_sym_eq_trivial
  1036   Eps_eq           -> some_eq_trivial
  1037 
  1038 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1039 
  1040 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1041 instead);
  1042 
  1043 * HOL: the recursion equations generated by 'recdef' are now called
  1044 f.simps instead of f.rules;
  1045 
  1046 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1047 
  1048 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1049 sometimes be needed;
  1050 
  1051 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1052 
  1053 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1054 
  1055 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1056 product is now "<*>" instead of "Times"; the lexicographic product is
  1057 now "<*lex*>" instead of "**";
  1058 
  1059 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1060 of main HOL, but was unused); better use HOL's datatype package;
  1061 
  1062 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1063 the old syntax may be recovered as follows:
  1064 
  1065   syntax (symbols)
  1066     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1067       (infixl "\\<oplus>" 100)
  1068 
  1069 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1070 
  1071 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1072 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1073 internally;
  1074 
  1075 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1076 changed from A/r to A//r;
  1077 
  1078 * ZF: new treatment of arithmetic (nat & int) may break some old
  1079 proofs;
  1080 
  1081 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1082 rulify -> rule_format, elimify -> elim_format, ...);
  1083 
  1084 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1085 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1086 should have to change intro!! to intro? only); replaced "delrule" by
  1087 "rule del";
  1088 
  1089 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1090 
  1091 * Provers: strengthened force_tac by using new first_best_tac;
  1092 
  1093 * LaTeX document preparation: several changes of isabelle.sty (see
  1094 lib/texinputs);
  1095 
  1096 
  1097 *** Document preparation ***
  1098 
  1099 * formal comments (text blocks etc.) in new-style theories may now
  1100 contain antiquotations of thm/prop/term/typ/text to be presented
  1101 according to latex print mode; concrete syntax is like this:
  1102 @{term[show_types] "f(x) = a + x"};
  1103 
  1104 * isatool mkdir provides easy setup of Isabelle session directories,
  1105 including proper document sources;
  1106 
  1107 * generated LaTeX sources are now deleted after successful run
  1108 (isatool document -c); may retain a copy somewhere else via -D option
  1109 of isatool usedir;
  1110 
  1111 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1112 style files, achieving self-contained LaTeX sources and simplifying
  1113 LaTeX debugging;
  1114 
  1115 * old-style theories now produce (crude) LaTeX output as well;
  1116 
  1117 * browser info session directories are now self-contained (may be put
  1118 on WWW server seperately); improved graphs of nested sessions; removed
  1119 graph for 'all sessions';
  1120 
  1121 * several improvements in isabelle style files; \isabellestyle{it}
  1122 produces fake math mode output; \isamarkupheader is now \section by
  1123 default; see lib/texinputs/isabelle.sty etc.;
  1124 
  1125 
  1126 *** Isar ***
  1127 
  1128 * Isar/Pure: local results and corresponding term bindings are now
  1129 subject to Hindley-Milner polymorphism (similar to ML); this
  1130 accommodates incremental type-inference very nicely;
  1131 
  1132 * Isar/Pure: new derived language element 'obtain' supports
  1133 generalized existence reasoning;
  1134 
  1135 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1136 support accumulation of results, without applying any rules yet;
  1137 useful to collect intermediate results without explicit name
  1138 references, and for use with transitivity rules with more than 2
  1139 premises;
  1140 
  1141 * Isar/Pure: scalable support for case-analysis type proofs: new
  1142 'case' language element refers to local contexts symbolically, as
  1143 produced by certain proof methods; internally, case names are attached
  1144 to theorems as "tags";
  1145 
  1146 * Isar/Pure: theory command 'hide' removes declarations from
  1147 class/type/const name spaces;
  1148 
  1149 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1150 indicate potential overloading;
  1151 
  1152 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1153 
  1154 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1155 "{a,b,c}" instead of {a,b,c};
  1156 
  1157 * Isar/Pure now provides its own version of intro/elim/dest
  1158 attributes; useful for building new logics, but beware of confusion
  1159 with the version in Provers/classical;
  1160 
  1161 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1162 case name 'antecedent';
  1163 
  1164 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1165 to the current context is now done automatically);
  1166 
  1167 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1168 for definining proof methods in ML;
  1169 
  1170 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1171 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1172 most cases, one should have to change intro!! to intro? only);
  1173 replaced "delrule" by "rule del";
  1174 
  1175 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1176 'symmetric' attribute (the latter supercedes [RS sym]);
  1177 
  1178 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1179 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1180 well (including splits);
  1181 
  1182 * Isar/Provers: Simplifier and Classical methods now support all kind
  1183 of modifiers used in the past, including 'cong', 'iff', etc.
  1184 
  1185 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1186 of Simplifier and Classical reasoner);
  1187 
  1188 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1189 now support named cases; major packages (inductive, datatype, primrec,
  1190 recdef) support case names and properly name parameters;
  1191 
  1192 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1193 monotonicity conditions are extracted to be proven at end of
  1194 calculations;
  1195 
  1196 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1197 method anyway;
  1198 
  1199 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1200 split_if split_if_asm; datatype package provides theorems foo.splits =
  1201 foo.split foo.split_asm for each datatype;
  1202 
  1203 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1204 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1205 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1206 use "(cases (simplified))" method in proper proof texts);
  1207 
  1208 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1209 
  1210 * Isar: names of theorems etc. may be natural numbers as well;
  1211 
  1212 * Isar: 'pr' command: optional arguments for goals_limit and
  1213 ProofContext.prems_limit; no longer prints theory contexts, but only
  1214 proof states;
  1215 
  1216 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1217 additional print modes to be specified; e.g. "pr(latex)" will print
  1218 proof state according to the Isabelle LaTeX style;
  1219 
  1220 * Isar: improved support for emulating tactic scripts, including proof
  1221 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1222 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1223 (for HOL datatypes);
  1224 
  1225 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1226 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1227 'proof method scripts' have to be in depth-first order;
  1228 
  1229 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1230 
  1231 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1232 should instead use individual commands for printing items
  1233 (print_commands, print_methods etc.);
  1234 
  1235 * Isar: added 'nothing' --- the empty list of theorems;
  1236 
  1237 
  1238 *** HOL ***
  1239 
  1240 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1241 corresponding virtual machine and a specification of its bytecode
  1242 verifier and a lightweight bytecode verifier, including proofs of
  1243 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1244 Cornelia Pusch (see also the homepage of project Bali at
  1245 http://isabelle.in.tum.de/Bali/);
  1246 
  1247 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1248 Clemens Ballarin;
  1249 
  1250 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1251 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1252 Rasmussen;
  1253 
  1254 * HOL/Lattice: fundamental concepts of lattice theory and order
  1255 structures, including duals, properties of bounds versus algebraic
  1256 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1257 Theorem for complete lattices etc.; may also serve as a demonstration
  1258 for abstract algebraic reasoning using axiomatic type classes, and
  1259 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1260 
  1261 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1262 von Oheimb;
  1263 
  1264 * HOL/IMPP: extension of IMP with local variables and mutually
  1265 recursive procedures, by David von Oheimb;
  1266 
  1267 * HOL/Lambda: converted into new-style theory and document;
  1268 
  1269 * HOL/ex/Multiquote: example of multiple nested quotations and
  1270 anti-quotations -- basically a generalized version of de-Bruijn
  1271 representation; very useful in avoiding lifting of operations;
  1272 
  1273 * HOL/record: added general record equality rule to simpset; fixed
  1274 select-update simplification procedure to handle extended records as
  1275 well; admit "r" as field name;
  1276 
  1277 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1278 other numeric types and also as the identity of groups, rings, etc.;
  1279 
  1280 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1281 Types nat and int belong to this axclass;
  1282 
  1283 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1284    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1285    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1286   two terms #m*u and #n*u are replaced by #(m+n)*u
  1287     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1288   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1289     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1290 
  1291 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1292 powerful prover for predicate logic but knows nothing of clasets; see
  1293 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1294 
  1295 * HOL: new version of "case_tac" subsumes both boolean case split and
  1296 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1297 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1298 
  1299 * HOL: simplification no longer dives into case-expressions: only the
  1300 selector expression is simplified, but not the remaining arms; to
  1301 enable full simplification of case-expressions for datatype t, you may
  1302 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1303 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1304 
  1305 * HOL/recdef: the recursion equations generated by 'recdef' for
  1306 function 'f' are now called f.simps instead of f.rules; if all
  1307 termination conditions are proved automatically, these simplification
  1308 rules are added to the simpset, as in primrec; rules may be named
  1309 individually as well, resulting in a separate list of theorems for
  1310 each equation;
  1311 
  1312 * HOL/While is a new theory that provides a while-combinator. It
  1313 permits the definition of tail-recursive functions without the
  1314 provision of a termination measure. The latter is necessary once the
  1315 invariant proof rule for while is applied.
  1316 
  1317 * HOL: new (overloaded) notation for the set of elements below/above
  1318 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1319 
  1320 * HOL: theorems impI, allI, ballI bound as "strip";
  1321 
  1322 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1323 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1324 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1325 
  1326 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1327 
  1328 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1329 main HOL, but was unused);
  1330 
  1331 * HOL: fewer consts declared as global (e.g. have to refer to
  1332 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1333 
  1334 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1335 in case of overlap with user translations (e.g. judgements over
  1336 tuples); (note that the underlying logical represenation is still
  1337 bogus);
  1338 
  1339 
  1340 *** ZF ***
  1341 
  1342 * ZF: simplification automatically cancels common terms in arithmetic
  1343 expressions over nat and int;
  1344 
  1345 * ZF: new treatment of nat to minimize type-checking: all operators
  1346 coerce their operands to a natural number using the function natify,
  1347 making the algebraic laws unconditional;
  1348 
  1349 * ZF: as above, for int: operators coerce their operands to an integer
  1350 using the function intify;
  1351 
  1352 * ZF: the integer library now contains many of the usual laws for the
  1353 orderings, including $<=, and monotonicity laws for $+ and $*;
  1354 
  1355 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1356 simplification;
  1357 
  1358 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1359 to the simplifier and classical reasoner simultaneously;
  1360 
  1361 
  1362 *** General ***
  1363 
  1364 * Provers: blast_tac now handles actual object-logic rules as
  1365 assumptions; note that auto_tac uses blast_tac internally as well;
  1366 
  1367 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1368 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1369 
  1370 * Provers: delrules now handles destruct rules as well (no longer need
  1371 explicit make_elim);
  1372 
  1373 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1374   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1375 use instead the strong form,
  1376   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1377 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1378 from destruct-rules;
  1379 
  1380 * Provers: Simplifier.easy_setup provides a fast path to basic
  1381 Simplifier setup for new object-logics;
  1382 
  1383 * Pure: AST translation rules no longer require constant head on LHS;
  1384 
  1385 * Pure: improved name spaces: ambiguous output is qualified; support
  1386 for hiding of names;
  1387 
  1388 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1389 XSYMBOL_HOME; no longer need to do manual configuration in most
  1390 situations;
  1391 
  1392 * system: compression of ML heaps images may now be controlled via -c
  1393 option of isabelle and isatool usedir (currently only observed by
  1394 Poly/ML);
  1395 
  1396 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1397 useful for remote X11);
  1398 
  1399 * system: provide TAGS file for Isabelle sources;
  1400 
  1401 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1402 order;
  1403 
  1404 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1405 timing flag supersedes proof_timing and Toplevel.trace;
  1406 
  1407 * ML: new combinators |>> and |>>> for incremental transformations
  1408 with secondary results (e.g. certain theory extensions):
  1409 
  1410 * ML: PureThy.add_defs gets additional argument to indicate potential
  1411 overloading (usually false);
  1412 
  1413 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1414 results;
  1415 
  1416 
  1417 
  1418 New in Isabelle99 (October 1999)
  1419 --------------------------------
  1420 
  1421 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1422 
  1423 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1424 are no longer simplified.  (This allows the simplifier to unfold recursive
  1425 functional programs.)  To restore the old behaviour, declare
  1426 
  1427     Delcongs [if_weak_cong];
  1428 
  1429 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1430 complement;
  1431 
  1432 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1433 
  1434 * HOL/datatype: mutual_induct_tac no longer exists --
  1435   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1436 
  1437 * HOL/typedef: fixed type inference for representing set; type
  1438 arguments now have to occur explicitly on the rhs as type constraints;
  1439 
  1440 * ZF: The con_defs part of an inductive definition may no longer refer
  1441 to constants declared in the same theory;
  1442 
  1443 * HOL, ZF: the function mk_cases, generated by the inductive
  1444 definition package, has lost an argument.  To simplify its result, it
  1445 uses the default simpset instead of a supplied list of theorems.
  1446 
  1447 * HOL/List: the constructors of type list are now Nil and Cons;
  1448 
  1449 * Simplifier: the type of the infix ML functions
  1450         setSSolver addSSolver setSolver addSolver
  1451 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1452 for packaging solvers. A solver is created via
  1453         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1454 where the string argument is only a comment.
  1455 
  1456 
  1457 *** Proof tools ***
  1458 
  1459 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1460 decision procedure for linear arithmetic. Currently it is used for
  1461 types `nat', `int', and `real' in HOL (see below); it can, should and
  1462 will be instantiated for other types and logics as well.
  1463 
  1464 * The simplifier now accepts rewrite rules with flexible heads, eg
  1465      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1466   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1467   matching.
  1468 
  1469 
  1470 *** General ***
  1471 
  1472 * New Isabelle/Isar subsystem provides an alternative to traditional
  1473 tactical theorem proving; together with the ProofGeneral/isar user
  1474 interface it offers an interactive environment for developing human
  1475 readable proof documents (Isar == Intelligible semi-automated
  1476 reasoning); for further information see isatool doc isar-ref,
  1477 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1478 
  1479 * improved and simplified presentation of theories: better HTML markup
  1480 (including colors), graph views in several sizes; isatool usedir now
  1481 provides a proper interface for user theories (via -P option); actual
  1482 document preparation based on (PDF)LaTeX is available as well (for
  1483 new-style theories only); see isatool doc system for more information;
  1484 
  1485 * native support for Proof General, both for classic Isabelle and
  1486 Isabelle/Isar;
  1487 
  1488 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1489 using the graph browser tool;
  1490 
  1491 * Isabelle manuals now also available as PDF;
  1492 
  1493 * theory loader rewritten from scratch (may not be fully
  1494 bug-compatible); old loadpath variable has been replaced by show_path,
  1495 add_path, del_path, reset_path functions; new operations such as
  1496 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1497 isatool doc ref);
  1498 
  1499 * improved isatool install: option -k creates KDE application icon,
  1500 option -p DIR installs standalone binaries;
  1501 
  1502 * added ML_PLATFORM setting (useful for cross-platform installations);
  1503 more robust handling of platform specific ML images for SML/NJ;
  1504 
  1505 * the settings environment is now statically scoped, i.e. it is never
  1506 created again in sub-processes invoked from isabelle, isatool, or
  1507 Isabelle;
  1508 
  1509 * path element specification '~~' refers to '$ISABELLE_HOME';
  1510 
  1511 * in locales, the "assumes" and "defines" parts may be omitted if
  1512 empty;
  1513 
  1514 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1515 long arrows);
  1516 
  1517 * new print_mode "HTML";
  1518 
  1519 * new flag show_tags controls display of tags of theorems (which are
  1520 basically just comments that may be attached by some tools);
  1521 
  1522 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1523 mode and goal output format:
  1524 
  1525 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1526 244c244
  1527 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1528 ---
  1529 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1530 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1531 181c181
  1532 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1533 ---
  1534 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1535 
  1536 * function bind_thms stores lists of theorems (cf. bind_thm);
  1537 
  1538 * new shorthand tactics ftac, eatac, datac, fatac;
  1539 
  1540 * qed (and friends) now accept "" as result name; in that case the
  1541 theorem is not stored, but proper checks and presentation of the
  1542 result still apply;
  1543 
  1544 * theorem database now also indexes constants "Trueprop", "all",
  1545 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1546 
  1547 
  1548 *** HOL ***
  1549 
  1550 ** HOL arithmetic **
  1551 
  1552 * There are now decision procedures for linear arithmetic over nat and
  1553 int:
  1554 
  1555 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1556 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1557 are treated as atomic; subformulae not involving type `nat' or `int'
  1558 are ignored; quantified subformulae are ignored unless they are
  1559 positive universal or negative existential. The tactic has to be
  1560 invoked by hand and can be a little bit slow. In particular, the
  1561 running time is exponential in the number of occurrences of `min' and
  1562 `max', and `-' on `nat'.
  1563 
  1564 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1565 (negated) (in)equalities among the premises and the conclusion into
  1566 account (i.e. no compound formulae) and does not know about `min' and
  1567 `max', and `-' on `nat'. It is fast and is used automatically by the
  1568 simplifier.
  1569 
  1570 NB: At the moment, these decision procedures do not cope with mixed
  1571 nat/int formulae where the two parts interact, such as `m < n ==>
  1572 int(m) < int(n)'.
  1573 
  1574 * HOL/Numeral provides a generic theory of numerals (encoded
  1575 efficiently as bit strings); setup for types nat/int/real is in place;
  1576 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1577 int, existing theories and proof scripts may require a few additional
  1578 type constraints;
  1579 
  1580 * integer division and remainder can now be performed on constant
  1581 arguments;
  1582 
  1583 * many properties of integer multiplication, division and remainder
  1584 are now available;
  1585 
  1586 * An interface to the Stanford Validity Checker (SVC) is available through the
  1587 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1588 are proved automatically.  SVC must be installed separately, and its results
  1589 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1590 invocation of the underlying oracle).  For SVC see
  1591   http://verify.stanford.edu/SVC
  1592 
  1593 * IsaMakefile: the HOL-Real target now builds an actual image;
  1594 
  1595 
  1596 ** HOL misc **
  1597 
  1598 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1599 (in Isabelle/Isar) -- by Gertrud Bauer;
  1600 
  1601 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1602 analysis for assembly languages with subtypes;
  1603 
  1604 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1605 -- avoids syntactic ambiguities and treats state, transition, and
  1606 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1607 changed syntax and (many) tactics;
  1608 
  1609 * HOL/inductive: Now also handles more general introduction rules such
  1610   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1611   theorems are now maintained within the theory (maintained via the
  1612   "mono" attribute);
  1613 
  1614 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1615   (using function types) such as
  1616 
  1617   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1618 
  1619 * HOL/record: record_simproc (part of the default simpset) takes care
  1620 of selectors applied to updated records; record_split_tac is no longer
  1621 part of the default claset; update_defs may now be removed from the
  1622 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1623 
  1624   claset_ref () := claset() addSWrapper record_split_wrapper;
  1625   Delsimprocs [record_simproc]
  1626 
  1627 * HOL/typedef: fixed type inference for representing set; type
  1628 arguments now have to occur explicitly on the rhs as type constraints;
  1629 
  1630 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1631 names rather than an ML expression;
  1632 
  1633 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1634 supplied later.  Program schemes can be defined, such as
  1635     "While B C s = (if B s then While B C (C s) else s)"
  1636 where the well-founded relation can be chosen after B and C have been given.
  1637 
  1638 * HOL/List: the constructors of type list are now Nil and Cons;
  1639 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1640 course, ML tools referring to List.list.op # etc. have to be adapted;
  1641 
  1642 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1643 disabled by default; run isabelle with option -m HOL to get back to
  1644 the original Gordon/HOL-style output;
  1645 
  1646 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1647 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1648 
  1649 * HOL basic syntax simplified (more orthogonal): all variants of
  1650 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1651 Eps operator is provided as well: "SOME x. P[x]";
  1652 
  1653 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1654 
  1655 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1656 thus available for user theories;
  1657 
  1658 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1659 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1660 time;
  1661 
  1662 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1663 several times and then mp;
  1664 
  1665 
  1666 *** LK ***
  1667 
  1668 * the notation <<...>> is now available as a notation for sequences of
  1669 formulas;
  1670 
  1671 * the simplifier is now installed
  1672 
  1673 * the axiom system has been generalized (thanks to Soren Heilmann)
  1674 
  1675 * the classical reasoner now has a default rule database
  1676 
  1677 
  1678 *** ZF ***
  1679 
  1680 * new primrec section allows primitive recursive functions to be given
  1681 directly (as in HOL) over datatypes and the natural numbers;
  1682 
  1683 * new tactics induct_tac and exhaust_tac for induction (or case
  1684 analysis) over datatypes and the natural numbers;
  1685 
  1686 * the datatype declaration of type T now defines the recursor T_rec;
  1687 
  1688 * simplification automatically does freeness reasoning for datatype
  1689 constructors;
  1690 
  1691 * automatic type-inference, with AddTCs command to insert new
  1692 type-checking rules;
  1693 
  1694 * datatype introduction rules are now added as Safe Introduction rules
  1695 to the claset;
  1696 
  1697 * the syntax "if P then x else y" is now available in addition to
  1698 if(P,x,y);
  1699 
  1700 
  1701 *** Internal programming interfaces ***
  1702 
  1703 * tuned simplifier trace output; new flag debug_simp;
  1704 
  1705 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1706 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1707 
  1708 * AxClass.axclass_tac lost the theory argument;
  1709 
  1710 * tuned current_goals_markers semantics: begin / end goal avoids
  1711 printing empty lines;
  1712 
  1713 * removed prs and prs_fn hook, which was broken because it did not
  1714 include \n in its semantics, forcing writeln to add one
  1715 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1716 string -> unit if you really want to output text without newline;
  1717 
  1718 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1719 plain output, interface builders may have to enable 'isabelle_font'
  1720 mode to get Isabelle font glyphs as before;
  1721 
  1722 * refined token_translation interface; INCOMPATIBILITY: output length
  1723 now of type real instead of int;
  1724 
  1725 * theory loader actions may be traced via new ThyInfo.add_hook
  1726 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1727 your own database of information attached to *whole* theories -- as
  1728 opposed to intra-theory data slots offered via TheoryDataFun;
  1729 
  1730 * proper handling of dangling sort hypotheses (at last!);
  1731 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1732 extra sort hypotheses that can be witnessed from the type signature;
  1733 the force_strip_shyps flag is gone, any remaining shyps are simply
  1734 left in the theorem (with a warning issued by strip_shyps_warning);
  1735 
  1736 
  1737 
  1738 New in Isabelle98-1 (October 1998)
  1739 ----------------------------------
  1740 
  1741 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1742 
  1743 * several changes of automated proof tools;
  1744 
  1745 * HOL: major changes to the inductive and datatype packages, including
  1746 some minor incompatibilities of theory syntax;
  1747 
  1748 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1749 called `inj_on';
  1750 
  1751 * HOL: removed duplicate thms in Arith:
  1752   less_imp_add_less  should be replaced by  trans_less_add1
  1753   le_imp_add_le      should be replaced by  trans_le_add1
  1754 
  1755 * HOL: unary minus is now overloaded (new type constraints may be
  1756 required);
  1757 
  1758 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1759 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1760 now taken as an integer constant.
  1761 
  1762 * Pure: ML function 'theory_of' renamed to 'theory';
  1763 
  1764 
  1765 *** Proof tools ***
  1766 
  1767 * Simplifier:
  1768   1. Asm_full_simp_tac is now more aggressive.
  1769      1. It will sometimes reorient premises if that increases their power to
  1770         simplify.
  1771      2. It does no longer proceed strictly from left to right but may also
  1772         rotate premises to achieve further simplification.
  1773      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1774      old Asm_full_simp_tac in that it does not rotate premises.
  1775   2. The simplifier now knows a little bit about nat-arithmetic.
  1776 
  1777 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1778 allows for selected deletion of wrappers, by introduction of names for
  1779 wrapper functionals.  This implies that addbefore, addSbefore,
  1780 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1781 and that adding two tactics with the same name overwrites the first
  1782 one (emitting a warning).
  1783   type wrapper = (int -> tactic) -> (int -> tactic)
  1784   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1785   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1786   delWrapper, delSWrapper: claset *  string            -> claset
  1787   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1788 
  1789 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1790 semantics; addbefore now affects only the unsafe part of step_tac
  1791 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1792 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1793 by Force_tac;
  1794 
  1795 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1796 compWrapper; added safe wrapper (and access functions for it);
  1797 
  1798 * HOL/split_all_tac is now much faster and fails if there is nothing
  1799 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1800 and the names of the automatically generated variables have changed.
  1801 split_all_tac has moved within claset() from unsafe wrappers to safe
  1802 wrappers, which means that !!-bound variables are split much more
  1803 aggressively, and safe_tac and clarify_tac now split such variables.
  1804 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1805 Note: the same holds for record_split_tac, which does the job of
  1806 split_all_tac for record fields.
  1807 
  1808 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1809 permanently to the default simpset using Addsplits just like
  1810 Addsimps. They can be removed via Delsplits just like
  1811 Delsimps. Lower-case versions are also available.
  1812 
  1813 * HOL/Simplifier: The rule split_if is now part of the default
  1814 simpset. This means that the simplifier will eliminate all occurrences
  1815 of if-then-else in the conclusion of a goal. To prevent this, you can
  1816 either remove split_if completely from the default simpset by
  1817 `Delsplits [split_if]' or remove it in a specific call of the
  1818 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1819 other case splitting rules to/from the default simpset: every datatype
  1820 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1821 t is the name of the datatype).
  1822 
  1823 * Classical reasoner / Simplifier combination: new force_tac (and
  1824 derivatives Force_tac, force) combines rewriting and classical
  1825 reasoning (and whatever other tools) similarly to auto_tac, but is
  1826 aimed to solve the given subgoal completely.
  1827 
  1828 
  1829 *** General ***
  1830 
  1831 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1832 and `goalw': the theory is no longer needed as an explicit argument -
  1833 the current theory context is used; assumptions are no longer returned
  1834 at the ML-level unless one of them starts with ==> or !!; it is
  1835 recommended to convert to these new commands using isatool fixgoal
  1836 (backup your sources first!);
  1837 
  1838 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1839 the current theory context, and 'theory' to lookup stored theories;
  1840 
  1841 * new theory section 'locale' for declaring constants, assumptions and
  1842 definitions that have local scope;
  1843 
  1844 * new theory section 'nonterminals' for purely syntactic types;
  1845 
  1846 * new theory section 'setup' for generic ML setup functions
  1847 (e.g. package initialization);
  1848 
  1849 * the distribution now includes Isabelle icons: see
  1850 lib/logo/isabelle-{small,tiny}.xpm;
  1851 
  1852 * isatool install - install binaries with absolute references to
  1853 ISABELLE_HOME/bin;
  1854 
  1855 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1856 
  1857 * print mode 'emacs' reserved for Isamode;
  1858 
  1859 * support multiple print (ast) translations per constant name;
  1860 
  1861 * theorems involving oracles are now printed with a suffixed [!];
  1862 
  1863 
  1864 *** HOL ***
  1865 
  1866 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1867 
  1868 * HOL/inductive package reorganized and improved: now supports mutual
  1869 definitions such as
  1870 
  1871   inductive EVEN ODD
  1872     intrs
  1873       null "0 : EVEN"
  1874       oddI "n : EVEN ==> Suc n : ODD"
  1875       evenI "n : ODD ==> Suc n : EVEN"
  1876 
  1877 new theorem list "elims" contains an elimination rule for each of the
  1878 recursive sets; inductive definitions now handle disjunctive premises
  1879 correctly (also ZF);
  1880 
  1881 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1882 "mutual_induct" no longer exists - the induction rule is always
  1883 contained in "induct";
  1884 
  1885 
  1886 * HOL/datatype package re-implemented and greatly improved: now
  1887 supports mutually recursive datatypes such as
  1888 
  1889   datatype
  1890     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1891             | SUM ('a aexp) ('a aexp)
  1892             | DIFF ('a aexp) ('a aexp)
  1893             | NUM 'a
  1894   and
  1895     'a bexp = LESS ('a aexp) ('a aexp)
  1896             | AND ('a bexp) ('a bexp)
  1897             | OR ('a bexp) ('a bexp)
  1898 
  1899 as well as indirectly recursive datatypes such as
  1900 
  1901   datatype
  1902     ('a, 'b) term = Var 'a
  1903                   | App 'b ((('a, 'b) term) list)
  1904 
  1905 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1906 induction on mutually / indirectly recursive datatypes.
  1907 
  1908 Primrec equations are now stored in theory and can be accessed via
  1909 <function_name>.simps.
  1910 
  1911 INCOMPATIBILITIES:
  1912 
  1913   - Theories using datatypes must now have theory Datatype as an
  1914     ancestor.
  1915   - The specific <typename>.induct_tac no longer exists - use the
  1916     generic induct_tac instead.
  1917   - natE has been renamed to nat.exhaust - use exhaust_tac
  1918     instead of res_inst_tac ... natE. Note that the variable
  1919     names in nat.exhaust differ from the names in natE, this
  1920     may cause some "fragile" proofs to fail.
  1921   - The theorems split_<typename>_case and split_<typename>_case_asm
  1922     have been renamed to <typename>.split and <typename>.split_asm.
  1923   - Since default sorts of type variables are now handled correctly,
  1924     some datatype definitions may have to be annotated with explicit
  1925     sort constraints.
  1926   - Primrec definitions no longer require function name and type
  1927     of recursive argument.
  1928 
  1929 Consider using isatool fixdatatype to adapt your theories and proof
  1930 scripts to the new package (backup your sources first!).
  1931 
  1932 
  1933 * HOL/record package: considerably improved implementation; now
  1934 includes concrete syntax for record types, terms, updates; theorems
  1935 for surjective pairing and splitting !!-bound record variables; proof
  1936 support is as follows:
  1937 
  1938   1) standard conversions (selectors or updates applied to record
  1939 constructor terms) are part of the standard simpset;
  1940 
  1941   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1942 made part of standard simpset and claset via addIffs;
  1943 
  1944   3) a tactic for record field splitting (record_split_tac) is part of
  1945 the standard claset (addSWrapper);
  1946 
  1947 To get a better idea about these rules you may retrieve them via
  1948 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1949 the name of your record type.
  1950 
  1951 The split tactic 3) conceptually simplifies by the following rule:
  1952 
  1953   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1954 
  1955 Thus any record variable that is bound by meta-all will automatically
  1956 blow up into some record constructor term, consequently the
  1957 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1958 solve record problems automatically.
  1959 
  1960 
  1961 * reorganized the main HOL image: HOL/Integ and String loaded by
  1962 default; theory Main includes everything;
  1963 
  1964 * automatic simplification of integer sums and comparisons, using cancellation;
  1965 
  1966 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1967 
  1968 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1969 
  1970 * many new identities for unions, intersections, set difference, etc.;
  1971 
  1972 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1973 called split_if, split_split, split_sum_case and split_nat_case (to go
  1974 with add/delsplits);
  1975 
  1976 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1977 (?x::unit) = (); this is made part of the default simpset, which COULD
  1978 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1979 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1980 unit_abs_eta_conv is added in order to counter the effect of
  1981 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1982 %u.f();
  1983 
  1984 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1985 makes more sense);
  1986 
  1987 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1988   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1989   disjointness reasoning but breaking a few old proofs.
  1990 
  1991 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1992 to 'converse' from 'inverse' (for compatibility with ZF and some
  1993 literature);
  1994 
  1995 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1996 the well-founded relation;
  1997 
  1998 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1999     Compl A.  The "Compl" syntax remains available as input syntax for this
  2000     release ONLY.
  2001 
  2002 * HOL/Update: new theory of function updates:
  2003     f(a:=b) == %x. if x=a then b else f x
  2004 may also be iterated as in f(a:=b,c:=d,...);
  2005 
  2006 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2007 
  2008 * HOL/List:
  2009   - new function list_update written xs[i:=v] that updates the i-th
  2010     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2011   - new function `upt' written [i..j(] which generates the list
  2012     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2013     bound write [i..j], which is a shorthand for [i..j+1(].
  2014   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2015 
  2016 * HOL/Arith:
  2017   - removed 'pred' (predecessor) function;
  2018   - generalized some theorems about n-1;
  2019   - many new laws about "div" and "mod";
  2020   - new laws about greatest common divisors (see theory ex/Primes);
  2021 
  2022 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2023 instead of "inverse";
  2024 
  2025 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2026   of the multiset ordering;
  2027 
  2028 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2029   (not included by default);
  2030 
  2031 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2032 
  2033 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2034   programs, i.e. different program variables may have different types.
  2035 
  2036 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2037   [previously, this check worked only if the rewrite rule was unconditional]
  2038   Now rew can involve either definitions or equalities (either == or =).
  2039 
  2040 
  2041 *** ZF ***
  2042 
  2043 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2044   only the theorems proved on ZF.ML;
  2045 
  2046 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2047   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2048   disjointness reasoning but breaking a few old proofs.
  2049 
  2050 * ZF/Update: new theory of function updates
  2051     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2052   may also be iterated as in f(a:=b,c:=d,...);
  2053 
  2054 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2055 
  2056 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2057   [previously, this check worked only if the rewrite rule was unconditional]
  2058   Now rew can involve either definitions or equalities (either == or =).
  2059 
  2060 * case_tac provided for compatibility with HOL
  2061     (like the old excluded_middle_tac, but with subgoals swapped)
  2062 
  2063 
  2064 *** Internal programming interfaces ***
  2065 
  2066 * Pure: several new basic modules made available for general use, see
  2067 also src/Pure/README;
  2068 
  2069 * improved the theory data mechanism to support encapsulation (data
  2070 kind name replaced by private Object.kind, acting as authorization
  2071 key); new type-safe user interface via functor TheoryDataFun; generic
  2072 print_data function becomes basically useless;
  2073 
  2074 * removed global_names compatibility flag -- all theory declarations
  2075 are qualified by default;
  2076 
  2077 * module Pure/Syntax now offers quote / antiquote translation
  2078 functions (useful for Hoare logic etc. with implicit dependencies);
  2079 see HOL/ex/Antiquote for an example use;
  2080 
  2081 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2082 cterm -> thm;
  2083 
  2084 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2085 subgoal;
  2086 
  2087 * Display.print_goals function moved to Locale.print_goals;
  2088 
  2089 * standard print function for goals supports current_goals_markers
  2090 variable for marking begin of proof, end of proof, start of goal; the
  2091 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2092 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2093 for example;
  2094 
  2095 
  2096 
  2097 New in Isabelle98 (January 1998)
  2098 --------------------------------
  2099 
  2100 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2101 
  2102 * changed lexical syntax of terms / types: dots made part of long
  2103 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2104 
  2105 * simpset (and claset) reference variable replaced by functions
  2106 simpset / simpset_ref;
  2107 
  2108 * no longer supports theory aliases (via merge) and non-trivial
  2109 implicit merge of thms' signatures;
  2110 
  2111 * most internal names of constants changed due to qualified names;
  2112 
  2113 * changed Pure/Sequence interface (see Pure/seq.ML);
  2114 
  2115 
  2116 *** General Changes ***
  2117 
  2118 * hierachically structured name spaces (for consts, types, axms, thms
  2119 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2120 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2121 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2122 long_names for fully qualified output names; NOTE: ML programs
  2123 (special tactics, packages etc.) referring to internal names may have
  2124 to be adapted to cope with fully qualified names; in case of severe
  2125 backward campatibility problems try setting 'global_names' at compile
  2126 time to have enrything declared within a flat name space; one may also
  2127 fine tune name declarations in theories via the 'global' and 'local'
  2128 section;
  2129 
  2130 * reimplemented the implicit simpset and claset using the new anytype
  2131 data filed in signatures; references simpset:simpset ref etc. are
  2132 replaced by functions simpset:unit->simpset and
  2133 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2134 to patch your ML files accordingly;
  2135 
  2136 * HTML output now includes theory graph data for display with Java
  2137 applet or isatool browser; data generated automatically via isatool
  2138 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2139 
  2140 * defs may now be conditional; improved rewrite_goals_tac to handle
  2141 conditional equations;
  2142 
  2143 * defs now admits additional type arguments, using TYPE('a) syntax;
  2144 
  2145 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2146 creates a new theory node; implicit merge of thms' signatures is
  2147 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2148 transfer:theory->thm->thm in (rare) cases;
  2149 
  2150 * improved handling of draft signatures / theories; draft thms (and
  2151 ctyps, cterms) are automatically promoted to real ones;
  2152 
  2153 * slightly changed interfaces for oracles: admit many per theory, named
  2154 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2155 
  2156 * print_goals: optional output of const types (set show_consts and
  2157 show_types);
  2158 
  2159 * improved output of warnings (###) and errors (***);
  2160 
  2161 * subgoal_tac displays a warning if the new subgoal has type variables;
  2162 
  2163 * removed old README and Makefiles;
  2164 
  2165 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2166 
  2167 * removed obsolete init_pps and init_database;
  2168 
  2169 * deleted the obsolete tactical STATE, which was declared by
  2170     fun STATE tacfun st = tacfun st st;
  2171 
  2172 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2173 (which abbreviates $HOME);
  2174 
  2175 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2176 use isatool fixseq to adapt your ML programs (this works for fully
  2177 qualified references to the Sequence structure only!);
  2178 
  2179 * use_thy no longer requires writable current directory; it always
  2180 reloads .ML *and* .thy file, if either one is out of date;
  2181 
  2182 
  2183 *** Classical Reasoner ***
  2184 
  2185 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2186 tactics that use classical reasoning to simplify a subgoal without
  2187 splitting it into several subgoals;
  2188 
  2189 * Safe_tac: like safe_tac but uses the default claset;
  2190 
  2191 
  2192 *** Simplifier ***
  2193 
  2194 * added simplification meta rules:
  2195     (asm_)(full_)simplify: simpset -> thm -> thm;
  2196 
  2197 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2198 logics (again);
  2199 
  2200 * added prems argument to simplification procedures;
  2201 
  2202 * HOL, FOL, ZF: added infix function `addsplits':
  2203   instead of `<simpset> setloop (split_tac <thms>)'
  2204   you can simply write `<simpset> addsplits <thms>'
  2205 
  2206 
  2207 *** Syntax ***
  2208 
  2209 * TYPE('a) syntax for type reflection terms;
  2210 
  2211 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2212 
  2213 * pretty printer: changed order of mixfix annotation preference (again!);
  2214 
  2215 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2216 
  2217 
  2218 *** HOL ***
  2219 
  2220 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2221   with `addloop' of the simplifier to faciliate case splitting in premises.
  2222 
  2223 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2224 
  2225 * HOL/Auth: new protocol proofs including some for the Internet
  2226   protocol TLS;
  2227 
  2228 * HOL/Map: new theory of `maps' a la VDM;
  2229 
  2230 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2231 cancelling out common nat summands from =, <, <= (in)equalities, or
  2232 differences; simplification procedures nat_cancel_factor for
  2233 cancelling common factor from =, <, <= (in)equalities over natural
  2234 sums; nat_cancel contains both kinds of procedures, it is installed by
  2235 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2236 
  2237 * HOL/simplifier: terms of the form
  2238   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2239   are rewritten to
  2240   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2241   and those of the form
  2242   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2243   are rewritten to
  2244   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2245 
  2246 * HOL/datatype
  2247   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2248 
  2249   P(t_case f1 ... fn x) =
  2250      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2251         ...
  2252        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2253      )
  2254 
  2255   and a theorem `split_t_case_asm' of the form
  2256 
  2257   P(t_case f1 ... fn x) =
  2258     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2259         ...
  2260        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2261      )
  2262   which can be added to a simpset via `addsplits'. The existing theorems
  2263   expand_list_case and expand_option_case have been renamed to
  2264   split_list_case and split_option_case.
  2265 
  2266 * HOL/Arithmetic:
  2267   - `pred n' is automatically converted to `n-1'.
  2268     Users are strongly encouraged not to use `pred' any longer,
  2269     because it will disappear altogether at some point.
  2270   - Users are strongly encouraged to write "0 < n" rather than
  2271     "n ~= 0". Theorems and proof tools have been modified towards this
  2272     `standard'.
  2273 
  2274 * HOL/Lists:
  2275   the function "set_of_list" has been renamed "set" (and its theorems too);
  2276   the function "nth" now takes its arguments in the reverse order and
  2277   has acquired the infix notation "!" as in "xs!n".
  2278 
  2279 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2280 
  2281 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2282   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2283 
  2284 * HOL/record: extensible records with schematic structural subtyping
  2285 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2286 still lacks various theorems and concrete record syntax;
  2287 
  2288 
  2289 *** HOLCF ***
  2290 
  2291 * removed "axioms" and "generated by" sections;
  2292 
  2293 * replaced "ops" section by extended "consts" section, which is capable of
  2294   handling the continuous function space "->" directly;
  2295 
  2296 * domain package:
  2297   . proves theorems immediately and stores them in the theory,
  2298   . creates hierachical name space,
  2299   . now uses normal mixfix annotations (instead of cinfix...),
  2300   . minor changes to some names and values (for consistency),
  2301   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2302   . separator between mutual domain defs: changed "," to "and",
  2303   . improved handling of sort constraints;  now they have to
  2304     appear on the left-hand side of the equations only;
  2305 
  2306 * fixed LAM <x,y,zs>.b syntax;
  2307 
  2308 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2309 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2310 
  2311 
  2312 *** FOL and ZF ***
  2313 
  2314 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2315   with `addloop' of the simplifier to faciliate case splitting in premises.
  2316 
  2317 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2318 in HOL, they strip ALL and --> from proved theorems;
  2319 
  2320 
  2321 
  2322 New in Isabelle94-8 (May 1997)
  2323 ------------------------------
  2324 
  2325 *** General Changes ***
  2326 
  2327 * new utilities to build / run / maintain Isabelle etc. (in parts
  2328 still somewhat experimental); old Makefiles etc. still functional;
  2329 
  2330 * new 'Isabelle System Manual';
  2331 
  2332 * INSTALL text, together with ./configure and ./build scripts;
  2333 
  2334 * reimplemented type inference for greater efficiency, better error
  2335 messages and clean internal interface;
  2336 
  2337 * prlim command for dealing with lots of subgoals (an easier way of
  2338 setting goals_limit);
  2339 
  2340 
  2341 *** Syntax ***
  2342 
  2343 * supports alternative (named) syntax tables (parser and pretty
  2344 printer); internal interface is provided by add_modesyntax(_i);
  2345 
  2346 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2347 be used in conjunction with the Isabelle symbol font; uses the
  2348 "symbols" syntax table;
  2349 
  2350 * added token_translation interface (may translate name tokens in
  2351 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2352 the current print_mode); IMPORTANT: user print translation functions
  2353 are responsible for marking newly introduced bounds
  2354 (Syntax.mark_boundT);
  2355 
  2356 * token translations for modes "xterm" and "xterm_color" that display
  2357 names in bold, underline etc. or colors (which requires a color
  2358 version of xterm);
  2359 
  2360 * infixes may now be declared with names independent of their syntax;
  2361 
  2362 * added typed_print_translation (like print_translation, but may
  2363 access type of constant);
  2364 
  2365 
  2366 *** Classical Reasoner ***
  2367 
  2368 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2369 some limitations.  Blast_tac...
  2370   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2371   + ignores elimination rules that don't have the correct format
  2372         (the conclusion MUST be a formula variable)
  2373   + ignores types, which can make HOL proofs fail
  2374   + rules must not require higher-order unification, e.g. apply_type in ZF
  2375     [message "Function Var's argument not a bound variable" relates to this]
  2376   + its proof strategy is more general but can actually be slower
  2377 
  2378 * substitution with equality assumptions no longer permutes other
  2379 assumptions;
  2380 
  2381 * minor changes in semantics of addafter (now called addaltern); renamed
  2382 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2383 (and access functions for it);
  2384 
  2385 * improved combination of classical reasoner and simplifier:
  2386   + functions for handling clasimpsets
  2387   + improvement of addss: now the simplifier is called _after_ the
  2388     safe steps.
  2389   + safe variant of addss called addSss: uses safe simplifications
  2390     _during_ the safe steps. It is more complete as it allows multiple
  2391     instantiations of unknowns (e.g. with slow_tac).
  2392 
  2393 *** Simplifier ***
  2394 
  2395 * added interface for simplification procedures (functions that
  2396 produce *proven* rewrite rules on the fly, depending on current
  2397 redex);
  2398 
  2399 * ordering on terms as parameter (used for ordered rewriting);
  2400 
  2401 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2402 
  2403 * the solver is now split into a safe and an unsafe part.
  2404 This should be invisible for the normal user, except that the
  2405 functions setsolver and addsolver have been renamed to setSolver and
  2406 addSolver; added safe_asm_full_simp_tac;
  2407 
  2408 
  2409 *** HOL ***
  2410 
  2411 * a generic induction tactic `induct_tac' which works for all datatypes and
  2412 also for type `nat';
  2413 
  2414 * a generic case distinction tactic `exhaust_tac' which works for all
  2415 datatypes and also for type `nat';
  2416 
  2417 * each datatype comes with a function `size';
  2418 
  2419 * patterns in case expressions allow tuple patterns as arguments to
  2420 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2421 
  2422 * primrec now also works with type nat;
  2423 
  2424 * recdef: a new declaration form, allows general recursive functions to be
  2425 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2426 
  2427 * the constant for negation has been renamed from "not" to "Not" to
  2428 harmonize with FOL, ZF, LK, etc.;
  2429 
  2430 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2431 infinite lists;
  2432 
  2433 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2434 
  2435 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2436 problems in commutative rings, using axiomatic type classes for + and *;
  2437 
  2438 * more examples in HOL/MiniML and HOL/Auth;
  2439 
  2440 * more default rewrite rules for quantifiers, union/intersection;
  2441 
  2442 * a new constant `arbitrary == @x.False';
  2443 
  2444 * HOLCF/IOA replaces old HOL/IOA;
  2445 
  2446 * HOLCF changes: derived all rules and arities
  2447   + axiomatic type classes instead of classes
  2448   + typedef instead of faking type definitions
  2449   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2450   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2451   + eliminated the types void, one, tr
  2452   + use unit lift and bool lift (with translations) instead of one and tr
  2453   + eliminated blift from Lift3.thy (use Def instead of blift)
  2454   all eliminated rules are derived as theorems --> no visible changes ;
  2455 
  2456 
  2457 *** ZF ***
  2458 
  2459 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2460 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2461 as ZF_cs addSIs [equalityI];
  2462 
  2463 
  2464 
  2465 New in Isabelle94-7 (November 96)
  2466 ---------------------------------
  2467 
  2468 * allowing negative levels (as offsets) in prlev and choplev;
  2469 
  2470 * super-linear speedup for large simplifications;
  2471 
  2472 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2473 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2474 FAIL); can suppress it using the command Delsimps (ex_simps @
  2475 all_simps); De Morgan laws are also now included, by default;
  2476 
  2477 * improved printing of ==>  :  ~:
  2478 
  2479 * new object-logic "Sequents" adds linear logic, while replacing LK
  2480 and Modal (thanks to Sara Kalvala);
  2481 
  2482 * HOL/Auth: correctness proofs for authentication protocols;
  2483 
  2484 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2485 examples on HOL/Auth);
  2486 
  2487 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2488 the rewriter and classical reasoner simultaneously;
  2489 
  2490 * function uresult no longer returns theorems in "standard" format;
  2491 regain previous version by: val uresult = standard o uresult;
  2492 
  2493 
  2494 
  2495 New in Isabelle94-6
  2496 -------------------
  2497 
  2498 * oracles -- these establish an interface between Isabelle and trusted
  2499 external reasoners, which may deliver results as theorems;
  2500 
  2501 * proof objects (in particular record all uses of oracles);
  2502 
  2503 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2504 
  2505 * "constdefs" section in theory files;
  2506 
  2507 * "primrec" section (HOL) no longer requires names;
  2508 
  2509 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2510 
  2511 
  2512 
  2513 New in Isabelle94-5
  2514 -------------------
  2515 
  2516 * reduced space requirements;
  2517 
  2518 * automatic HTML generation from theories;
  2519 
  2520 * theory files no longer require "..." (quotes) around most types;
  2521 
  2522 * new examples, including two proofs of the Church-Rosser theorem;
  2523 
  2524 * non-curried (1994) version of HOL is no longer distributed;
  2525 
  2526 
  2527 
  2528 New in Isabelle94-4
  2529 -------------------
  2530 
  2531 * greatly reduced space requirements;
  2532 
  2533 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2534 
  2535 * searchable theorem database (see the section "Retrieving theorems" on
  2536 page 8 of the Reference Manual);
  2537 
  2538 * new examples, including Grabczewski's monumental case study of the
  2539 Axiom of Choice;
  2540 
  2541 * The previous version of HOL renamed to Old_HOL;
  2542 
  2543 * The new version of HOL (previously called CHOL) uses a curried syntax
  2544 for functions.  Application looks like f a b instead of f(a,b);
  2545 
  2546 * Mutually recursive inductive definitions finally work in HOL;
  2547 
  2548 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2549 translates to the operator "split";
  2550 
  2551 
  2552 
  2553 New in Isabelle94-3
  2554 -------------------
  2555 
  2556 * new infix operator, addss, allowing the classical reasoner to
  2557 perform simplification at each step of its search.  Example:
  2558         fast_tac (cs addss ss)
  2559 
  2560 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2561 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2562 look like (a,b) instead of <a,b>;
  2563 
  2564 * PLEASE NOTE: CHOL will eventually replace HOL!
  2565 
  2566 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2567 It translates to the operator "split".  A new theory of integers is available;
  2568 
  2569 * In ZF, integer numerals now denote two's-complement binary integers.
  2570 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2571 
  2572 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2573 of the Axiom of Choice;
  2574 
  2575 
  2576 
  2577 New in Isabelle94-2
  2578 -------------------
  2579 
  2580 * Significantly faster resolution;
  2581 
  2582 * the different sections in a .thy file can now be mixed and repeated
  2583 freely;
  2584 
  2585 * Database of theorems for FOL, HOL and ZF.  New
  2586 commands including qed, qed_goal and bind_thm store theorems in the database.
  2587 
  2588 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2589 a given theory (thms_of), or find out what theory a theorem was proved in
  2590 (theory_of_thm);
  2591 
  2592 * Bugs fixed in the inductive definition and datatype packages;
  2593 
  2594 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2595 and HOL_dup_cs obsolete;
  2596 
  2597 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2598 have been removed;
  2599 
  2600 * Simpler definition of function space in ZF;
  2601 
  2602 * new results about cardinal and ordinal arithmetic in ZF;
  2603 
  2604 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2605 types;
  2606 
  2607 
  2608 $Id$