NEWS
author wenzelm
Sat May 29 14:54:58 2004 +0200 (2004-05-29)
changeset 14816 b77cebcd7e6e
parent 14795 b702848de41f
child 14854 61bdf2ae4dc5
permissions -rw-r--r--
* ML: all output via channels of writeln etc. passed through Output.output;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: considerably improved version of 'constdefs' command.  Now
    10   performs automatic type-inference of declared constants; additional
    11   support for local structure declarations (cf. locales and HOL
    12   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    13   to observe strictly sequential dependencies of definitions within a
    14   single 'constdefs' section; moreover, the declared name needs to be
    15   an identifier.  If all fails, consider to fall back on 'consts' and
    16   'defs' separately.
    17 
    18 * Pure: improved indexed syntax and implicit structures.  First of
    19   all, indexed syntax provides a notational device for subscripted
    20   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    21   expressions.  Secondly, in a local context with structure
    22   declarations, number indexes \<^sub>n or the empty index (default
    23   number 1) refer to a certain fixed variable implicitly; option
    24   show_structs controls printing of implicit structures.  Typical
    25   applications of these concepts involve record types and locales.
    26 
    27 * Pure: clear separation of logical types and nonterminals, where the
    28   latter may only occur in 'syntax' specifications or type
    29   abbreviations.  Before that distinction was only partially
    30   implemented via type class "logic" vs. "{}".  Potential
    31   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    32   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    33   specifications may require further adaption (e.g. Cube/Base.thy).
    34 
    35 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    36 
    37 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    38   specified in mixfix annotations as "(00...)".
    39 
    40 * Pure/Syntax: 'advanced' translation functions (parse_translation
    41   etc.) may depend on the signature of the theory context being
    42   presently used for parsing/printing, see also isar-ref manual.
    43 
    44 * Pure: tuned internal renaming of symbolic identifiers -- attach
    45   primes instead of base 26 numbers.
    46 
    47 * ML: all output via channels of writeln/warning/error etc. is now
    48   passed through Output.output.  This gives interface builders a
    49   chance to adapt text encodings in arbitrary manners (say as XML
    50   entities); see the hook provided by Output.add_mode.  On the other
    51   hand, results of Pretty.string_of/str_of (including string_of_term,
    52   string_of_thm etc.) are still 'raw' (containing funny \<^raw...>
    53   symbols), which requires separate application of Output.output
    54   whenever strings are *not* passed on to writeln/warning/error etc.
    55 
    56 
    57 *** HOL ***
    58 
    59 * HOL/record: reimplementation of records. Improved scalability for
    60   records with many fields, avoiding performance problems for type
    61   inference. Records are no longer composed of nested field types, but
    62   of nested extension types. Therefore the record type only grows
    63   linear in the number of extensions and not in the number of fields.
    64   The top-level (users) view on records is preserved.  Potential
    65   INCOMPATIBILITY only in strange cases, where the theory depends on
    66   the old record representation. The type generated for a record is
    67   called <record_name>_ext_type.
    68 
    69 * Simplifier: "record_upd_simproc" for simplification of multiple
    70   record updates enabled by default.  INCOMPATIBILITY: old proofs
    71   break occasionally, since simplification is more powerful by
    72   default.
    73 
    74 
    75 *** HOLCF ***
    76 
    77 * HOLCF: discontinued special version of 'constdefs' (which used to
    78   support continuous functions) in favor of the general Pure one with
    79   full type-inference.
    80 
    81 
    82 
    83 New in Isabelle2004 (April 2004)
    84 --------------------------------
    85 
    86 *** General ***
    87 
    88 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    89   Replaces linorder.ML.
    90 
    91 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
    92   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
    93   (\<a>...\<z>), are now considered normal letters, and can therefore
    94   be used anywhere where an ASCII letter (a...zA...Z) has until
    95   now. COMPATIBILITY: This obviously changes the parsing of some
    96   terms, especially where a symbol has been used as a binder, say
    97   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    98   as an identifier.  Fix it by inserting a space around former
    99   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   100   existing theory and ML files.
   101 
   102 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   103 
   104 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   105   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   106   a normal (but invisible) letter. For multiple letter subscripts repeat
   107   \<^isub> like this: x\<^isub>1\<^isub>2.
   108 
   109 * Pure: There are now sub-/superscripts that can span more than one
   110   character. Text between \<^bsub> and \<^esub> is set in subscript in
   111   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   112   superscript. The new control characters are not identifier parts.
   113 
   114 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   115   content of "..." to the latex file instead of \isacntrl... . The "..."
   116   may consist of any printable characters excluding the end bracket >.
   117 
   118 * Pure: Using new Isar command "finalconsts" (or the ML functions
   119   Theory.add_finals or Theory.add_finals_i) it is now possible to
   120   declare constants "final", which prevents their being given a definition
   121   later.  It is useful for constants whose behaviour is fixed axiomatically
   122   rather than definitionally, such as the meta-logic connectives.
   123 
   124 * Pure: 'instance' now handles general arities with general sorts
   125   (i.e. intersections of classes),
   126 
   127 * Presentation: generated HTML now uses a CSS style sheet to make layout
   128   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   129   It can be changed to alter the colors/layout of generated pages.
   130 
   131 
   132 *** Isar ***
   133 
   134 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   135   cut_tac, subgoal_tac and thin_tac:
   136   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   137     locales are no longer forced to write Isar proof scripts.
   138     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   139     emulations.
   140   - INCOMPATIBILITY: names of variables to be instantiated may no
   141     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   142     This is consistent with the instantiation attribute "where".
   143 
   144 * Attributes "where" and "of":
   145   - Now take type variables of instantiated theorem into account when reading
   146     the instantiation string.  This fixes a bug that caused instantiated
   147     theorems to have too special types in some circumstances.
   148   - "where" permits explicit instantiations of type variables.
   149 
   150 * Calculation commands "moreover" and "also" no longer interfere with
   151   current facts ("this"), admitting arbitrary combinations with "then"
   152   and derived forms.
   153 
   154 * Locales:
   155   - Goal statements involving the context element "includes" no longer
   156     generate theorems with internal delta predicates (those ending on
   157     "_axioms") in the premise.
   158     Resolve particular premise with <locale>.intro to obtain old form.
   159   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   160     specification and "includes" elements in goal statement.
   161   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   162     [intro?] and [elim?] (respectively) by default.
   163   - Experimental command for instantiation of locales in proof contexts:
   164         instantiate <label>[<attrs>]: <loc>
   165     Instantiates locale <loc> and adds all its theorems to the current context
   166     taking into account their attributes.  Label and attrs are optional
   167     modifiers, like in theorem declarations.  If present, names of
   168     instantiated theorems are qualified with <label>, and the attributes
   169     <attrs> are applied after any attributes these theorems might have already.
   170       If the locale has assumptions, a chained fact of the form
   171     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   172     are derived.  The command does not support old-style locales declared
   173     with "locale (open)".
   174       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   175 
   176 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   177   (Isar) contexts.
   178 
   179 
   180 *** HOL ***
   181 
   182 * Proof import: new image HOL4 contains the imported library from
   183   the HOL4 system with about 2500 theorems. It is imported by
   184   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   185   can be used like any other Isabelle image.  See
   186   HOL/Import/HOL/README for more information.
   187 
   188 * Simplifier:
   189   - Much improved handling of linear and partial orders.
   190     Reasoners for linear and partial orders are set up for type classes
   191     "linorder" and "order" respectively, and are added to the default simpset
   192     as solvers.  This means that the simplifier can build transitivity chains
   193     to solve goals from the assumptions.
   194   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   195     of blast or auto after simplification become unnecessary because the goal
   196     is solved by simplification already.
   197 
   198 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   199     all proved in axiomatic type classes for semirings, rings and fields.
   200 
   201 * Numerics:
   202   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   203     now formalized using the Ring_and_Field theory mentioned above.
   204   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   205     than before, because now they are set up once in a generic manner.
   206   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   207     Look for the general versions in Ring_and_Field (and Power if they concern
   208     exponentiation).
   209 
   210 * Type "rat" of the rational numbers is now available in HOL-Complex.
   211 
   212 * Records:
   213   - Record types are now by default printed with their type abbreviation
   214     instead of the list of all field types. This can be configured via
   215     the reference "print_record_type_abbr".
   216   - Simproc "record_upd_simproc" for simplification of multiple updates added
   217     (not enabled by default).
   218   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   219     EX x. x = sel r to True (not enabled by default).
   220   - Tactic "record_split_simp_tac" to split and simplify records added.
   221 
   222 * 'specification' command added, allowing for definition by
   223   specification.  There is also an 'ax_specification' command that
   224   introduces the new constants axiomatically.
   225 
   226 * arith(_tac) is now able to generate counterexamples for reals as well.
   227 
   228 * HOL-Algebra: new locale "ring" for non-commutative rings.
   229 
   230 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   231   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   232 
   233 * HOL-Matrix: a first theory for matrices in HOL with an application of
   234   matrix theory to linear programming.
   235 
   236 * Unions and Intersections:
   237   The x-symbol output syntax of UN and INT has been changed
   238   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   239   i.e. the index formulae has become a subscript, like in normal math.
   240   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   241   The subscript version is also accepted as input syntax.
   242 
   243 * Unions and Intersections over Intervals:
   244   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   245   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   246   like in normal math, and corresponding versions for < and for intersection.
   247 
   248 * ML: the legacy theory structures Int and List have been removed. They had
   249   conflicted with ML Basis Library structures having the same names.
   250 
   251 * 'refute' command added to search for (finite) countermodels.  Only works
   252   for a fragment of HOL.  The installation of an external SAT solver is
   253   highly recommended.  See "HOL/Refute.thy" for details.
   254 
   255 * 'quickcheck' command: Allows to find counterexamples by evaluating
   256   formulae under an assignment of free variables to random values.
   257   In contrast to 'refute', it can deal with inductive datatypes,
   258   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   259   for examples.
   260 
   261 
   262 *** HOLCF ***
   263 
   264 * Streams now come with concatenation and are part of the HOLCF image
   265 
   266 
   267 
   268 New in Isabelle2003 (May 2003)
   269 ------------------------------
   270 
   271 *** General ***
   272 
   273 * Provers/simplifier:
   274 
   275   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   276     Assumptions are now subject to complete mutual simplification,
   277     not just from left to right. The simplifier now preserves
   278     the order of assumptions.
   279 
   280     Potential INCOMPATIBILITY:
   281 
   282     -- simp sometimes diverges where the old version did
   283        not, e.g. invoking simp on the goal
   284 
   285         [| P (f x); y = x; f x = f y |] ==> Q
   286 
   287        now gives rise to the infinite reduction sequence
   288 
   289         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   290 
   291        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   292        kind of problem.
   293 
   294     -- Tactics combining classical reasoner and simplification (such as auto)
   295        are also affected by this change, because many of them rely on
   296        simp. They may sometimes diverge as well or yield a different numbers
   297        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   298        in case of problems. Sometimes subsequent calls to the classical
   299        reasoner will fail because a preceeding call to the simplifier too
   300        eagerly simplified the goal, e.g. deleted redundant premises.
   301 
   302   - The simplifier trace now shows the names of the applied rewrite rules
   303 
   304   - You can limit the number of recursive invocations of the simplifier
   305     during conditional rewriting (where the simplifie tries to solve the
   306     conditions before applying the rewrite rule):
   307     ML "simp_depth_limit := n"
   308     where n is an integer. Thus you can force termination where previously
   309     the simplifier would diverge.
   310 
   311   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   312 
   313   - No longer aborts on failed congruence proof.  Instead, the
   314     congruence is ignored.
   315 
   316 * Pure: New generic framework for extracting programs from constructive
   317   proofs. See HOL/Extraction.thy for an example instantiation, as well
   318   as HOL/Extraction for some case studies.
   319 
   320 * Pure: The main goal of the proof state is no longer shown by default, only
   321 the subgoals. This behaviour is controlled by a new flag.
   322    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   323 (ML: Proof.show_main_goal).
   324 
   325 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   326 rules whose conclusion matches subgoal 1:
   327       PG menu: Isabelle/Isar -> Show me -> matching rules
   328 The rules are ordered by how closely they match the subgoal.
   329 In particular, rules that solve a subgoal outright are displayed first
   330 (or rather last, the way they are printed).
   331 (ML: ProofGeneral.print_intros())
   332 
   333 * Pure: New flag trace_unify_fail causes unification to print
   334 diagnostic information (PG: in trace buffer) when it fails. This is
   335 useful for figuring out why single step proofs like rule, erule or
   336 assumption failed.
   337 
   338 * Pure: Locale specifications now produce predicate definitions
   339 according to the body of text (covering assumptions modulo local
   340 definitions); predicate "loc_axioms" covers newly introduced text,
   341 while "loc" is cumulative wrt. all included locale expressions; the
   342 latter view is presented only on export into the global theory
   343 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   344 on the old view without predicates;
   345 
   346 * Pure: predefined locales "var" and "struct" are useful for sharing
   347 parameters (as in CASL, for example); just specify something like
   348 ``var x + var y + struct M'' as import;
   349 
   350 * Pure: improved thms_containing: proper indexing of facts instead of
   351 raw theorems; check validity of results wrt. current name space;
   352 include local facts of proof configuration (also covers active
   353 locales), cover fixed variables in index; may use "_" in term
   354 specification; an optional limit for the number of printed facts may
   355 be given (the default is 40);
   356 
   357 * Pure: disallow duplicate fact bindings within new-style theory files
   358 (batch-mode only);
   359 
   360 * Provers: improved induct method: assumptions introduced by case
   361 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   362 the goal statement); "foo" still refers to all facts collectively;
   363 
   364 * Provers: the function blast.overloaded has been removed: all constants
   365 are regarded as potentially overloaded, which improves robustness in exchange
   366 for slight decrease in efficiency;
   367 
   368 * Provers/linorder: New generic prover for transitivity reasoning over
   369 linear orders.  Note: this prover is not efficient!
   370 
   371 * Isar: preview of problems to finish 'show' now produce an error
   372 rather than just a warning (in interactive mode);
   373 
   374 
   375 *** HOL ***
   376 
   377 * arith(_tac)
   378 
   379  - Produces a counter example if it cannot prove a goal.
   380    Note that the counter example may be spurious if the goal is not a formula
   381    of quantifier-free linear arithmetic.
   382    In ProofGeneral the counter example appears in the trace buffer.
   383 
   384  - Knows about div k and mod k where k is a numeral of type nat or int.
   385 
   386  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   387    linear arithmetic fails. This takes account of quantifiers and divisibility.
   388    Presburger arithmetic can also be called explicitly via presburger(_tac).
   389 
   390 * simp's arithmetic capabilities have been enhanced a bit: it now
   391 takes ~= in premises into account (by performing a case split);
   392 
   393 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   394 are distributed over a sum of terms;
   395 
   396 * New tactic "trans_tac" and method "trans" instantiate
   397 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   398 "<=", "<" and "=").
   399 
   400 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   401 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   402 
   403 * 'typedef' command has new option "open" to suppress the set
   404 definition;
   405 
   406 * functions Min and Max on finite sets have been introduced (theory
   407 Finite_Set);
   408 
   409 * attribute [symmetric] now works for relations as well; it turns
   410 (x,y) : R^-1 into (y,x) : R, and vice versa;
   411 
   412 * induct over a !!-quantified statement (say !!x1..xn):
   413   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   414 
   415 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   416 %x. None. Warning: empty_def now refers to the previously hidden definition
   417 of the empty set.
   418 
   419 * Algebra: formalization of classical algebra.  Intended as base for
   420 any algebraic development in Isabelle.  Currently covers group theory
   421 (up to Sylow's theorem) and ring theory (Universal Property of
   422 Univariate Polynomials).  Contributions welcome;
   423 
   424 * GroupTheory: deleted, since its material has been moved to Algebra;
   425 
   426 * Complex: new directory of the complex numbers with numeric constants,
   427 nonstandard complex numbers, and some complex analysis, standard and
   428 nonstandard (Jacques Fleuriot);
   429 
   430 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   431 
   432 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   433 Fleuriot);
   434 
   435 * Real/HahnBanach: updated and adapted to locales;
   436 
   437 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   438 Gray and Kramer);
   439 
   440 * UNITY: added the Meier-Sanders theory of progress sets;
   441 
   442 * MicroJava: bytecode verifier and lightweight bytecode verifier
   443 as abstract algorithms, instantiated to the JVM;
   444 
   445 * Bali: Java source language formalization. Type system, operational
   446 semantics, axiomatic semantics. Supported language features:
   447 classes, interfaces, objects,virtual methods, static methods,
   448 static/instance fields, arrays, access modifiers, definite
   449 assignment, exceptions.
   450 
   451 
   452 *** ZF ***
   453 
   454 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   455 universe, etc.);
   456 
   457 * Main ZF: virtually all theories converted to new-style format;
   458 
   459 
   460 *** ML ***
   461 
   462 * Pure: Tactic.prove provides sane interface for internal proofs;
   463 omits the infamous "standard" operation, so this is more appropriate
   464 than prove_goalw_cterm in many situations (e.g. in simprocs);
   465 
   466 * Pure: improved error reporting of simprocs;
   467 
   468 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   469 up simprocs;
   470 
   471 
   472 *** Document preparation ***
   473 
   474 * uses \par instead of \\ for line breaks in theory text. This may
   475 shift some page breaks in large documents. To get the old behaviour
   476 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   477 
   478 * minimized dependencies of isabelle.sty and isabellesym.sty on
   479 other packages
   480 
   481 * \<euro> now needs package babel/greek instead of marvosym (which
   482 broke \Rightarrow)
   483 
   484 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   485 textcomp package)
   486 
   487 
   488 
   489 New in Isabelle2002 (March 2002)
   490 --------------------------------
   491 
   492 *** Document preparation ***
   493 
   494 * greatly simplified document preparation setup, including more
   495 graceful interpretation of isatool usedir -i/-d/-D options, and more
   496 instructive isatool mkdir; users should basically be able to get
   497 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   498 users may run a separate document processing stage manually like this:
   499 "isatool usedir -D output HOL Test && isatool document Test/output";
   500 
   501 * theory dependency graph may now be incorporated into documents;
   502 isatool usedir -g true will produce session_graph.eps/.pdf for use
   503 with \includegraphics of LaTeX;
   504 
   505 * proper spacing of consecutive markup elements, especially text
   506 blocks after section headings;
   507 
   508 * support bold style (for single symbols only), input syntax is like
   509 this: "\<^bold>\<alpha>" or "\<^bold>A";
   510 
   511 * \<bullet> is now output as bold \cdot by default, which looks much
   512 better in printed text;
   513 
   514 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   515 note that these symbols are currently unavailable in Proof General /
   516 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   517 
   518 * isatool latex no longer depends on changed TEXINPUTS, instead
   519 isatool document copies the Isabelle style files to the target
   520 location;
   521 
   522 
   523 *** Isar ***
   524 
   525 * Pure/Provers: improved proof by cases and induction;
   526   - 'case' command admits impromptu naming of parameters (such as
   527     "case (Suc n)");
   528   - 'induct' method divinates rule instantiation from the inductive
   529     claim; no longer requires excessive ?P bindings for proper
   530     instantiation of cases;
   531   - 'induct' method properly enumerates all possibilities of set/type
   532     rules; as a consequence facts may be also passed through *type*
   533     rules without further ado;
   534   - 'induct' method now derives symbolic cases from the *rulified*
   535     rule (before it used to rulify cases stemming from the internal
   536     atomized version); this means that the context of a non-atomic
   537     statement becomes is included in the hypothesis, avoiding the
   538     slightly cumbersome show "PROP ?case" form;
   539   - 'induct' may now use elim-style induction rules without chaining
   540     facts, using ``missing'' premises from the goal state; this allows
   541     rules stemming from inductive sets to be applied in unstructured
   542     scripts, while still benefitting from proper handling of non-atomic
   543     statements; NB: major inductive premises need to be put first, all
   544     the rest of the goal is passed through the induction;
   545   - 'induct' proper support for mutual induction involving non-atomic
   546     rule statements (uses the new concept of simultaneous goals, see
   547     below);
   548   - append all possible rule selections, but only use the first
   549     success (no backtracking);
   550   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   551   - undeclared rule case names default to numbers 1, 2, 3, ...;
   552   - added 'print_induct_rules' (covered by help item in recent Proof
   553     General versions);
   554   - moved induct/cases attributes to Pure, methods to Provers;
   555   - generic method setup instantiated for FOL and HOL;
   556 
   557 * Pure: support multiple simultaneous goal statements, for example
   558 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   559 meta-level mechanism, this acts as if several individual goals had
   560 been stated separately; in particular common proof methods need to be
   561 repeated in order to cover all claims; note that a single elimination
   562 step is *not* sufficient to establish the two conjunctions, so this
   563 fails:
   564 
   565   assume "A & B" then have A and B ..   (*".." fails*)
   566 
   567 better use "obtain" in situations as above; alternative refer to
   568 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   569 
   570 * Pure: proper integration with ``locales''; unlike the original
   571 version by Florian Kammüller, Isar locales package high-level proof
   572 contexts rather than raw logical ones (e.g. we admit to include
   573 attributes everywhere); operations on locales include merge and
   574 rename; support for implicit arguments (``structures''); simultaneous
   575 type-inference over imports and text; see also HOL/ex/Locales.thy for
   576 some examples;
   577 
   578 * Pure: the following commands have been ``localized'', supporting a
   579 target locale specification "(in name)": 'lemma', 'theorem',
   580 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   581 stored both within the locale and at the theory level (exported and
   582 qualified by the locale name);
   583 
   584 * Pure: theory goals may now be specified in ``long'' form, with
   585 ad-hoc contexts consisting of arbitrary locale elements. for example
   586 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   587 definitions may be given, too); the result is a meta-level rule with
   588 the context elements being discharged in the obvious way;
   589 
   590 * Pure: new proof command 'using' allows to augment currently used
   591 facts after a goal statement ('using' is syntactically analogous to
   592 'apply', but acts on the goal's facts only); this allows chained facts
   593 to be separated into parts given before and after a claim, as in
   594 ``from a and b have C using d and e <proof>'';
   595 
   596 * Pure: renamed "antecedent" case to "rule_context";
   597 
   598 * Pure: new 'judgment' command records explicit information about the
   599 object-logic embedding (used by several tools internally); no longer
   600 use hard-wired "Trueprop";
   601 
   602 * Pure: added 'corollary' command;
   603 
   604 * Pure: fixed 'token_translation' command;
   605 
   606 * Pure: removed obsolete 'exported' attribute;
   607 
   608 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   609 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   610 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   611 
   612 * Pure: method 'atomize' presents local goal premises as object-level
   613 statements (atomic meta-level propositions); setup controlled via
   614 rewrite rules declarations of 'atomize' attribute; example
   615 application: 'induct' method with proper rule statements in improper
   616 proof *scripts*;
   617 
   618 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   619 now consider the syntactic context of assumptions, giving a better
   620 chance to get type-inference of the arguments right (this is
   621 especially important for locales);
   622 
   623 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   624 mode;
   625 
   626 * Pure/obtain: the formal conclusion "thesis", being marked as
   627 ``internal'', may no longer be reference directly in the text;
   628 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   629 situations;
   630 
   631 * Pure: generic 'sym' attribute which declares a rule both as pure
   632 'elim?' and for the 'symmetric' operation;
   633 
   634 * Pure: marginal comments ``--'' may now occur just anywhere in the
   635 text; the fixed correlation with particular command syntax has been
   636 discontinued;
   637 
   638 * Pure: new method 'rules' is particularly well-suited for proof
   639 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   640 but often produces more compact proof terms with less detours;
   641 
   642 * Pure/Provers/classical: simplified integration with pure rule
   643 attributes and methods; the classical "intro?/elim?/dest?"
   644 declarations coincide with the pure ones; the "rule" method no longer
   645 includes classically swapped intros; "intro" and "elim" methods no
   646 longer pick rules from the context; also got rid of ML declarations
   647 AddXIs/AddXEs/AddXDs; all of this has some potential for
   648 INCOMPATIBILITY;
   649 
   650 * Provers/classical: attribute 'swapped' produces classical inversions
   651 of introduction rules;
   652 
   653 * Provers/simplifier: 'simplified' attribute may refer to explicit
   654 rules instead of full simplifier context; 'iff' attribute handles
   655 conditional rules;
   656 
   657 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   658 
   659 * HOL: 'recdef' now fails on unfinished automated proofs, use
   660 "(permissive)" option to recover old behavior;
   661 
   662 * HOL: 'inductive' no longer features separate (collective) attributes
   663 for 'intros' (was found too confusing);
   664 
   665 * HOL: properly declared induction rules less_induct and
   666 wf_induct_rule;
   667 
   668 
   669 *** HOL ***
   670 
   671 * HOL: moved over to sane numeral syntax; the new policy is as
   672 follows:
   673 
   674   - 0 and 1 are polymorphic constants, which are defined on any
   675   numeric type (nat, int, real etc.);
   676 
   677   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   678   binary representation internally;
   679 
   680   - type nat has special constructor Suc, and generally prefers Suc 0
   681   over 1::nat and Suc (Suc 0) over 2::nat;
   682 
   683 This change may cause significant problems of INCOMPATIBILITY; here
   684 are some hints on converting existing sources:
   685 
   686   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   687   entities, so expressions involving "-" (unary or binary minus) need
   688   to be spaced properly;
   689 
   690   - existing occurrences of "1" may need to be constraint "1::nat" or
   691   even replaced by Suc 0; similar for old "2";
   692 
   693   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   694 
   695   - remove all special provisions on numerals in proofs;
   696 
   697 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   698 representation (depends on bin_arith_simps in the default context);
   699 
   700 * HOL: symbolic syntax for x^2 (numeral 2);
   701 
   702 * HOL: the class of all HOL types is now called "type" rather than
   703 "term"; INCOMPATIBILITY, need to adapt references to this type class
   704 in axclass/classes, instance/arities, and (usually rare) occurrences
   705 in typings (of consts etc.); internally the class is called
   706 "HOL.type", ML programs should refer to HOLogic.typeS;
   707 
   708 * HOL/record package improvements:
   709   - new derived operations "fields" to build a partial record section,
   710     "extend" to promote a fixed record to a record scheme, and
   711     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   712     declared as simp by default;
   713   - shared operations ("more", "fields", etc.) now need to be always
   714     qualified) --- potential INCOMPATIBILITY;
   715   - removed "make_scheme" operations (use "make" with "extend") --
   716     INCOMPATIBILITY;
   717   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   718   - provides cases/induct rules for use with corresponding Isar
   719     methods (for concrete records, record schemes, concrete more
   720     parts, and schematic more parts -- in that order);
   721   - internal definitions directly based on a light-weight abstract
   722     theory of product types over typedef rather than datatype;
   723 
   724 * HOL: generic code generator for generating executable ML code from
   725 specifications; specific support for HOL constructs such as inductive
   726 datatypes and sets, as well as recursive functions; can be invoked
   727 via 'generate_code' theory section;
   728 
   729 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   730 
   731 * HOL: consolidated and renamed several theories.  In particular:
   732         Ord.thy has been absorbed into HOL.thy
   733         String.thy has been absorbed into List.thy
   734 
   735 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   736 (beware of argument permutation!);
   737 
   738 * HOL: linorder_less_split superseded by linorder_cases;
   739 
   740 * HOL/List: "nodups" renamed to "distinct";
   741 
   742 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   743 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   744   - Ex_def has changed, now need to use some_eq_ex
   745 
   746 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   747 in this (rare) case use:
   748 
   749   delSWrapper "split_all_tac"
   750   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   751 
   752 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   753 MAY FAIL;
   754 
   755 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   756 Isabelle's type classes, ^ on functions and relations has too general
   757 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   758 necessary to attach explicit type constraints;
   759 
   760 * HOL/Relation: the prefix name of the infix "O" has been changed from
   761 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   762 renamed accordingly (eg "compI" -> "rel_compI").
   763 
   764 * HOL: syntax translations now work properly with numerals and records
   765 expressions;
   766 
   767 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   768 of "lam" -- INCOMPATIBILITY;
   769 
   770 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   771 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   772 renamed "Product_Type.unit";
   773 
   774 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   775 
   776 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   777 the "cases" method);
   778 
   779 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   780 Florian Kammüller);
   781 
   782 * HOL/IMP: updated and converted to new-style theory format; several
   783 parts turned into readable document, with proper Isar proof texts and
   784 some explanations (by Gerwin Klein);
   785 
   786 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   787 
   788 * HOL-Hyperreal is now a logic image;
   789 
   790 
   791 *** HOLCF ***
   792 
   793 * Isar: consts/constdefs supports mixfix syntax for continuous
   794 operations;
   795 
   796 * Isar: domain package adapted to new-style theory format, e.g. see
   797 HOLCF/ex/Dnat.thy;
   798 
   799 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   800 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   801 lift.induct_tac, always use UU instead of Undef;
   802 
   803 * HOLCF/IMP: updated and converted to new-style theory;
   804 
   805 
   806 *** ZF ***
   807 
   808 * Isar: proper integration of logic-specific tools and packages,
   809 including theory commands '(co)inductive', '(co)datatype',
   810 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   811 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   812 
   813 * theory Main no longer includes AC; for the Axiom of Choice, base
   814 your theory on Main_ZFC;
   815 
   816 * the integer library now covers quotients and remainders, with many
   817 laws relating division to addition, multiplication, etc.;
   818 
   819 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   820 typeless version of the formalism;
   821 
   822 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   823 format;
   824 
   825 * ZF/Induct: new directory for examples of inductive definitions,
   826 including theory Multiset for multiset orderings; converted to
   827 new-style theory format;
   828 
   829 * ZF: many new theorems about lists, ordinals, etc.;
   830 
   831 
   832 *** General ***
   833 
   834 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   835 variable proof controls level of detail: 0 = no proofs (only oracle
   836 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   837 also ref manual for further ML interfaces;
   838 
   839 * Pure/axclass: removed obsolete ML interface
   840 goal_subclass/goal_arity;
   841 
   842 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   843 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   844 separate tokens, so expressions involving minus need to be spaced
   845 properly;
   846 
   847 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   848 rather than "infixl" or "infixr";
   849 
   850 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   851 sort constraint specifications in type inference; e.g. "x::_::foo"
   852 ensures that the type of "x" is of sort "foo" (but not necessarily a
   853 type variable);
   854 
   855 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   856 control output of nested => (types); the default behavior is
   857 "type_brackets";
   858 
   859 * Pure/syntax: builtin parse translation for "_constify" turns valued
   860 tokens into AST constants;
   861 
   862 * Pure/syntax: prefer later declarations of translations and print
   863 translation functions; potential INCOMPATIBILITY: need to reverse
   864 multiple declarations for same syntax element constant;
   865 
   866 * Pure/show_hyps reset by default (in accordance to existing Isar
   867 practice);
   868 
   869 * Provers/classical: renamed addaltern to addafter, addSaltern to
   870 addSafter;
   871 
   872 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   873 as well;
   874 
   875 * system: tested support for MacOS X; should be able to get Isabelle +
   876 Proof General to work in a plain Terminal after installing Poly/ML
   877 (e.g. from the Isabelle distribution area) and GNU bash alone
   878 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   879 support requires further installations, e.g. from
   880 http://fink.sourceforge.net/);
   881 
   882 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   883 
   884 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   885 of 40 MB), cf. ML_OPTIONS;
   886 
   887 * system: Proof General keywords specification is now part of the
   888 Isabelle distribution (see etc/isar-keywords.el);
   889 
   890 * system: support for persistent Proof General sessions (refrain from
   891 outdating all loaded theories on startup); user may create writable
   892 logic images like this: ``isabelle -q HOL Test'';
   893 
   894 * system: smart selection of Isabelle process versus Isabelle
   895 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   896 run both "isabelle" and "Isabelle" even if file names are badly
   897 damaged (executable inspects the case of the first letter of its own
   898 name); added separate "isabelle-process" and "isabelle-interface";
   899 
   900 * system: refrain from any attempt at filtering input streams; no
   901 longer support ``8bit'' encoding of old isabelle font, instead proper
   902 iso-latin characters may now be used; the related isatools
   903 "symbolinput" and "nonascii" have disappeared as well;
   904 
   905 * system: removed old "xterm" interface (the print modes "xterm" and
   906 "xterm_color" are still available for direct use in a suitable
   907 terminal);
   908 
   909 
   910 
   911 New in Isabelle99-2 (February 2001)
   912 -----------------------------------
   913 
   914 *** Overview of INCOMPATIBILITIES ***
   915 
   916 * HOL: please note that theories in the Library and elsewhere often use the
   917 new-style (Isar) format; to refer to their theorems in an ML script you must
   918 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   919 
   920 * HOL: inductive package no longer splits induction rule aggressively,
   921 but only as far as specified by the introductions given; the old
   922 format may be recovered via ML function complete_split_rule or attribute
   923 'split_rule (complete)';
   924 
   925 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   926 gfp_Tarski to gfp_unfold;
   927 
   928 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   929 
   930 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   931 relation); infix "^^" has been renamed "``"; infix "``" has been
   932 renamed "`"; "univalent" has been renamed "single_valued";
   933 
   934 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   935 operation;
   936 
   937 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   938 
   939 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   940 
   941 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   942 consequence, it is no longer monotonic wrt. the local goal context
   943 (which is now passed through the inductive cases);
   944 
   945 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   946 \<gg> to \<ggreater>;
   947 
   948 
   949 *** Document preparation ***
   950 
   951 * \isabellestyle{NAME} selects version of Isabelle output (currently
   952 available: are "it" for near math-mode best-style output, "sl" for
   953 slanted text style, and "tt" for plain type-writer; if no
   954 \isabellestyle command is given, output is according to slanted
   955 type-writer);
   956 
   957 * support sub/super scripts (for single symbols only), input syntax is
   958 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   959 
   960 * some more standard symbols; see Appendix A of the system manual for
   961 the complete list of symbols defined in isabellesym.sty;
   962 
   963 * improved isabelle style files; more abstract symbol implementation
   964 (should now use \isamath{...} and \isatext{...} in custom symbol
   965 definitions);
   966 
   967 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   968 state; Note that presentation of goal states does not conform to
   969 actual human-readable proof documents.  Please do not include goal
   970 states into document output unless you really know what you are doing!
   971 
   972 * proper indentation of antiquoted output with proportional LaTeX
   973 fonts;
   974 
   975 * no_document ML operator temporarily disables LaTeX document
   976 generation;
   977 
   978 * isatool unsymbolize tunes sources for plain ASCII communication;
   979 
   980 
   981 *** Isar ***
   982 
   983 * Pure: Isar now suffers initial goal statements to contain unbound
   984 schematic variables (this does not conform to actual readable proof
   985 documents, due to unpredictable outcome and non-compositional proof
   986 checking); users who know what they are doing may use schematic goals
   987 for Prolog-style synthesis of proven results;
   988 
   989 * Pure: assumption method (an implicit finishing) now handles actual
   990 rules as well;
   991 
   992 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   993 initial goal, declare "that" only as Pure intro (only for single
   994 steps); the "that" rule assumption may now be involved in implicit
   995 finishing, thus ".." becomes a feasible for trivial obtains;
   996 
   997 * Pure: default proof step now includes 'intro_classes'; thus trivial
   998 instance proofs may be performed by "..";
   999 
  1000 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1001 statements as well;
  1002 
  1003 * Pure: more robust selection of calculational rules;
  1004 
  1005 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1006 rule (as well as the assumption rule);
  1007 
  1008 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1009 lemmas, using the graph browser tool;
  1010 
  1011 * Pure: predict failure of "show" in interactive mode;
  1012 
  1013 * Pure: 'thms_containing' now takes actual terms as arguments;
  1014 
  1015 * HOL: improved method 'induct' --- now handles non-atomic goals
  1016 (potential INCOMPATIBILITY); tuned error handling;
  1017 
  1018 * HOL: cases and induct rules now provide explicit hints about the
  1019 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1020 any remaining facts are inserted into the goal verbatim;
  1021 
  1022 * HOL: local contexts (aka cases) may now contain term bindings as
  1023 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1024 the result to be shown in each case;
  1025 
  1026 * HOL: added 'recdef_tc' command;
  1027 
  1028 * isatool convert assists in eliminating legacy ML scripts;
  1029 
  1030 
  1031 *** HOL ***
  1032 
  1033 * HOL/Library: a collection of generic theories to be used together
  1034 with main HOL; the theory loader path already includes this directory
  1035 by default; the following existing theories have been moved here:
  1036 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1037 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1038 
  1039 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1040 modelling and verification task performed in Isabelle/HOL +
  1041 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1042 
  1043 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1044 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1045 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1046 'domain', this makes the theory consistent with mathematical
  1047 literature;
  1048 
  1049 * HOL basics: added overloaded operations "inverse" and "divide"
  1050 (infix "/"), syntax for generic "abs" operation, generic summation
  1051 operator \<Sum>;
  1052 
  1053 * HOL/typedef: simplified package, provide more useful rules (see also
  1054 HOL/subset.thy);
  1055 
  1056 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1057 now expressed as a proper nested rule (old-style tactic scripts may
  1058 require atomize_strip_tac to cope with non-atomic premises);
  1059 
  1060 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1061 to "split_conv" (old name still available for compatibility);
  1062 
  1063 * HOL: improved concrete syntax for strings (e.g. allows translation
  1064 rules with string literals);
  1065 
  1066 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1067  and Fleuriot's mechanization of analysis, including the transcendental
  1068  functions for the reals;
  1069 
  1070 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1071 
  1072 
  1073 *** CTT ***
  1074 
  1075 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1076 "lam" is displayed as TWO lambda-symbols
  1077 
  1078 * CTT: theory Main now available, containing everything (that is, Bool
  1079 and Arith);
  1080 
  1081 
  1082 *** General ***
  1083 
  1084 * Pure: the Simplifier has been implemented properly as a derived rule
  1085 outside of the actual kernel (at last!); the overall performance
  1086 penalty in practical applications is about 50%, while reliability of
  1087 the Isabelle inference kernel has been greatly improved;
  1088 
  1089 * print modes "brackets" and "no_brackets" control output of nested =>
  1090 (types) and ==> (props); the default behaviour is "brackets";
  1091 
  1092 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1093 as assumptions as well;
  1094 
  1095 * system: support Poly/ML 4.0;
  1096 
  1097 * system: isatool install handles KDE version 1 or 2;
  1098 
  1099 
  1100 
  1101 New in Isabelle99-1 (October 2000)
  1102 ----------------------------------
  1103 
  1104 *** Overview of INCOMPATIBILITIES ***
  1105 
  1106 * HOL: simplification of natural numbers is much changed; to partly
  1107 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1108 issue the following ML commands:
  1109 
  1110   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1111   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1112 
  1113 * HOL: simplification no longer dives into case-expressions; this is
  1114 controlled by "t.weak_case_cong" for each datatype t;
  1115 
  1116 * HOL: nat_less_induct renamed to less_induct;
  1117 
  1118 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1119 fixsome to patch .thy and .ML sources automatically;
  1120 
  1121   select_equality  -> some_equality
  1122   select_eq_Ex     -> some_eq_ex
  1123   selectI2EX       -> someI2_ex
  1124   selectI2         -> someI2
  1125   selectI          -> someI
  1126   select1_equality -> some1_equality
  1127   Eps_sym_eq       -> some_sym_eq_trivial
  1128   Eps_eq           -> some_eq_trivial
  1129 
  1130 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1131 
  1132 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1133 instead);
  1134 
  1135 * HOL: the recursion equations generated by 'recdef' are now called
  1136 f.simps instead of f.rules;
  1137 
  1138 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1139 
  1140 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1141 sometimes be needed;
  1142 
  1143 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1144 
  1145 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1146 
  1147 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1148 product is now "<*>" instead of "Times"; the lexicographic product is
  1149 now "<*lex*>" instead of "**";
  1150 
  1151 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1152 of main HOL, but was unused); better use HOL's datatype package;
  1153 
  1154 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1155 the old syntax may be recovered as follows:
  1156 
  1157   syntax (symbols)
  1158     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1159       (infixl "\\<oplus>" 100)
  1160 
  1161 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1162 
  1163 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1164 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1165 internally;
  1166 
  1167 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1168 changed from A/r to A//r;
  1169 
  1170 * ZF: new treatment of arithmetic (nat & int) may break some old
  1171 proofs;
  1172 
  1173 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1174 rulify -> rule_format, elimify -> elim_format, ...);
  1175 
  1176 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1177 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1178 should have to change intro!! to intro? only); replaced "delrule" by
  1179 "rule del";
  1180 
  1181 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1182 
  1183 * Provers: strengthened force_tac by using new first_best_tac;
  1184 
  1185 * LaTeX document preparation: several changes of isabelle.sty (see
  1186 lib/texinputs);
  1187 
  1188 
  1189 *** Document preparation ***
  1190 
  1191 * formal comments (text blocks etc.) in new-style theories may now
  1192 contain antiquotations of thm/prop/term/typ/text to be presented
  1193 according to latex print mode; concrete syntax is like this:
  1194 @{term[show_types] "f(x) = a + x"};
  1195 
  1196 * isatool mkdir provides easy setup of Isabelle session directories,
  1197 including proper document sources;
  1198 
  1199 * generated LaTeX sources are now deleted after successful run
  1200 (isatool document -c); may retain a copy somewhere else via -D option
  1201 of isatool usedir;
  1202 
  1203 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1204 style files, achieving self-contained LaTeX sources and simplifying
  1205 LaTeX debugging;
  1206 
  1207 * old-style theories now produce (crude) LaTeX output as well;
  1208 
  1209 * browser info session directories are now self-contained (may be put
  1210 on WWW server seperately); improved graphs of nested sessions; removed
  1211 graph for 'all sessions';
  1212 
  1213 * several improvements in isabelle style files; \isabellestyle{it}
  1214 produces fake math mode output; \isamarkupheader is now \section by
  1215 default; see lib/texinputs/isabelle.sty etc.;
  1216 
  1217 
  1218 *** Isar ***
  1219 
  1220 * Isar/Pure: local results and corresponding term bindings are now
  1221 subject to Hindley-Milner polymorphism (similar to ML); this
  1222 accommodates incremental type-inference very nicely;
  1223 
  1224 * Isar/Pure: new derived language element 'obtain' supports
  1225 generalized existence reasoning;
  1226 
  1227 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1228 support accumulation of results, without applying any rules yet;
  1229 useful to collect intermediate results without explicit name
  1230 references, and for use with transitivity rules with more than 2
  1231 premises;
  1232 
  1233 * Isar/Pure: scalable support for case-analysis type proofs: new
  1234 'case' language element refers to local contexts symbolically, as
  1235 produced by certain proof methods; internally, case names are attached
  1236 to theorems as "tags";
  1237 
  1238 * Isar/Pure: theory command 'hide' removes declarations from
  1239 class/type/const name spaces;
  1240 
  1241 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1242 indicate potential overloading;
  1243 
  1244 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1245 
  1246 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1247 "{a,b,c}" instead of {a,b,c};
  1248 
  1249 * Isar/Pure now provides its own version of intro/elim/dest
  1250 attributes; useful for building new logics, but beware of confusion
  1251 with the version in Provers/classical;
  1252 
  1253 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1254 case name 'antecedent';
  1255 
  1256 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1257 to the current context is now done automatically);
  1258 
  1259 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1260 for definining proof methods in ML;
  1261 
  1262 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1263 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1264 most cases, one should have to change intro!! to intro? only);
  1265 replaced "delrule" by "rule del";
  1266 
  1267 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1268 'symmetric' attribute (the latter supercedes [RS sym]);
  1269 
  1270 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1271 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1272 well (including splits);
  1273 
  1274 * Isar/Provers: Simplifier and Classical methods now support all kind
  1275 of modifiers used in the past, including 'cong', 'iff', etc.
  1276 
  1277 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1278 of Simplifier and Classical reasoner);
  1279 
  1280 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1281 now support named cases; major packages (inductive, datatype, primrec,
  1282 recdef) support case names and properly name parameters;
  1283 
  1284 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1285 monotonicity conditions are extracted to be proven at end of
  1286 calculations;
  1287 
  1288 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1289 method anyway;
  1290 
  1291 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1292 split_if split_if_asm; datatype package provides theorems foo.splits =
  1293 foo.split foo.split_asm for each datatype;
  1294 
  1295 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1296 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1297 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1298 use "(cases (simplified))" method in proper proof texts);
  1299 
  1300 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1301 
  1302 * Isar: names of theorems etc. may be natural numbers as well;
  1303 
  1304 * Isar: 'pr' command: optional arguments for goals_limit and
  1305 ProofContext.prems_limit; no longer prints theory contexts, but only
  1306 proof states;
  1307 
  1308 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1309 additional print modes to be specified; e.g. "pr(latex)" will print
  1310 proof state according to the Isabelle LaTeX style;
  1311 
  1312 * Isar: improved support for emulating tactic scripts, including proof
  1313 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1314 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1315 (for HOL datatypes);
  1316 
  1317 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1318 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1319 'proof method scripts' have to be in depth-first order;
  1320 
  1321 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1322 
  1323 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1324 should instead use individual commands for printing items
  1325 (print_commands, print_methods etc.);
  1326 
  1327 * Isar: added 'nothing' --- the empty list of theorems;
  1328 
  1329 
  1330 *** HOL ***
  1331 
  1332 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1333 corresponding virtual machine and a specification of its bytecode
  1334 verifier and a lightweight bytecode verifier, including proofs of
  1335 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1336 Cornelia Pusch (see also the homepage of project Bali at
  1337 http://isabelle.in.tum.de/Bali/);
  1338 
  1339 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1340 Clemens Ballarin;
  1341 
  1342 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1343 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1344 Rasmussen;
  1345 
  1346 * HOL/Lattice: fundamental concepts of lattice theory and order
  1347 structures, including duals, properties of bounds versus algebraic
  1348 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1349 Theorem for complete lattices etc.; may also serve as a demonstration
  1350 for abstract algebraic reasoning using axiomatic type classes, and
  1351 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1352 
  1353 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1354 von Oheimb;
  1355 
  1356 * HOL/IMPP: extension of IMP with local variables and mutually
  1357 recursive procedures, by David von Oheimb;
  1358 
  1359 * HOL/Lambda: converted into new-style theory and document;
  1360 
  1361 * HOL/ex/Multiquote: example of multiple nested quotations and
  1362 anti-quotations -- basically a generalized version of de-Bruijn
  1363 representation; very useful in avoiding lifting of operations;
  1364 
  1365 * HOL/record: added general record equality rule to simpset; fixed
  1366 select-update simplification procedure to handle extended records as
  1367 well; admit "r" as field name;
  1368 
  1369 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1370 other numeric types and also as the identity of groups, rings, etc.;
  1371 
  1372 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1373 Types nat and int belong to this axclass;
  1374 
  1375 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1376    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1377    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1378   two terms #m*u and #n*u are replaced by #(m+n)*u
  1379     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1380   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1381     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1382 
  1383 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1384 powerful prover for predicate logic but knows nothing of clasets; see
  1385 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1386 
  1387 * HOL: new version of "case_tac" subsumes both boolean case split and
  1388 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1389 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1390 
  1391 * HOL: simplification no longer dives into case-expressions: only the
  1392 selector expression is simplified, but not the remaining arms; to
  1393 enable full simplification of case-expressions for datatype t, you may
  1394 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1395 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1396 
  1397 * HOL/recdef: the recursion equations generated by 'recdef' for
  1398 function 'f' are now called f.simps instead of f.rules; if all
  1399 termination conditions are proved automatically, these simplification
  1400 rules are added to the simpset, as in primrec; rules may be named
  1401 individually as well, resulting in a separate list of theorems for
  1402 each equation;
  1403 
  1404 * HOL/While is a new theory that provides a while-combinator. It
  1405 permits the definition of tail-recursive functions without the
  1406 provision of a termination measure. The latter is necessary once the
  1407 invariant proof rule for while is applied.
  1408 
  1409 * HOL: new (overloaded) notation for the set of elements below/above
  1410 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1411 
  1412 * HOL: theorems impI, allI, ballI bound as "strip";
  1413 
  1414 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1415 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1416 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1417 
  1418 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1419 
  1420 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1421 main HOL, but was unused);
  1422 
  1423 * HOL: fewer consts declared as global (e.g. have to refer to
  1424 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1425 
  1426 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1427 in case of overlap with user translations (e.g. judgements over
  1428 tuples); (note that the underlying logical represenation is still
  1429 bogus);
  1430 
  1431 
  1432 *** ZF ***
  1433 
  1434 * ZF: simplification automatically cancels common terms in arithmetic
  1435 expressions over nat and int;
  1436 
  1437 * ZF: new treatment of nat to minimize type-checking: all operators
  1438 coerce their operands to a natural number using the function natify,
  1439 making the algebraic laws unconditional;
  1440 
  1441 * ZF: as above, for int: operators coerce their operands to an integer
  1442 using the function intify;
  1443 
  1444 * ZF: the integer library now contains many of the usual laws for the
  1445 orderings, including $<=, and monotonicity laws for $+ and $*;
  1446 
  1447 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1448 simplification;
  1449 
  1450 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1451 to the simplifier and classical reasoner simultaneously;
  1452 
  1453 
  1454 *** General ***
  1455 
  1456 * Provers: blast_tac now handles actual object-logic rules as
  1457 assumptions; note that auto_tac uses blast_tac internally as well;
  1458 
  1459 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1460 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1461 
  1462 * Provers: delrules now handles destruct rules as well (no longer need
  1463 explicit make_elim);
  1464 
  1465 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1466   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1467 use instead the strong form,
  1468   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1469 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1470 from destruct-rules;
  1471 
  1472 * Provers: Simplifier.easy_setup provides a fast path to basic
  1473 Simplifier setup for new object-logics;
  1474 
  1475 * Pure: AST translation rules no longer require constant head on LHS;
  1476 
  1477 * Pure: improved name spaces: ambiguous output is qualified; support
  1478 for hiding of names;
  1479 
  1480 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1481 XSYMBOL_HOME; no longer need to do manual configuration in most
  1482 situations;
  1483 
  1484 * system: compression of ML heaps images may now be controlled via -c
  1485 option of isabelle and isatool usedir (currently only observed by
  1486 Poly/ML);
  1487 
  1488 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1489 useful for remote X11);
  1490 
  1491 * system: provide TAGS file for Isabelle sources;
  1492 
  1493 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1494 order;
  1495 
  1496 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1497 timing flag supersedes proof_timing and Toplevel.trace;
  1498 
  1499 * ML: new combinators |>> and |>>> for incremental transformations
  1500 with secondary results (e.g. certain theory extensions):
  1501 
  1502 * ML: PureThy.add_defs gets additional argument to indicate potential
  1503 overloading (usually false);
  1504 
  1505 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1506 results;
  1507 
  1508 
  1509 
  1510 New in Isabelle99 (October 1999)
  1511 --------------------------------
  1512 
  1513 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1514 
  1515 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1516 are no longer simplified.  (This allows the simplifier to unfold recursive
  1517 functional programs.)  To restore the old behaviour, declare
  1518 
  1519     Delcongs [if_weak_cong];
  1520 
  1521 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1522 complement;
  1523 
  1524 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1525 
  1526 * HOL/datatype: mutual_induct_tac no longer exists --
  1527   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1528 
  1529 * HOL/typedef: fixed type inference for representing set; type
  1530 arguments now have to occur explicitly on the rhs as type constraints;
  1531 
  1532 * ZF: The con_defs part of an inductive definition may no longer refer
  1533 to constants declared in the same theory;
  1534 
  1535 * HOL, ZF: the function mk_cases, generated by the inductive
  1536 definition package, has lost an argument.  To simplify its result, it
  1537 uses the default simpset instead of a supplied list of theorems.
  1538 
  1539 * HOL/List: the constructors of type list are now Nil and Cons;
  1540 
  1541 * Simplifier: the type of the infix ML functions
  1542         setSSolver addSSolver setSolver addSolver
  1543 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1544 for packaging solvers. A solver is created via
  1545         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1546 where the string argument is only a comment.
  1547 
  1548 
  1549 *** Proof tools ***
  1550 
  1551 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1552 decision procedure for linear arithmetic. Currently it is used for
  1553 types `nat', `int', and `real' in HOL (see below); it can, should and
  1554 will be instantiated for other types and logics as well.
  1555 
  1556 * The simplifier now accepts rewrite rules with flexible heads, eg
  1557      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1558   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1559   matching.
  1560 
  1561 
  1562 *** General ***
  1563 
  1564 * New Isabelle/Isar subsystem provides an alternative to traditional
  1565 tactical theorem proving; together with the ProofGeneral/isar user
  1566 interface it offers an interactive environment for developing human
  1567 readable proof documents (Isar == Intelligible semi-automated
  1568 reasoning); for further information see isatool doc isar-ref,
  1569 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1570 
  1571 * improved and simplified presentation of theories: better HTML markup
  1572 (including colors), graph views in several sizes; isatool usedir now
  1573 provides a proper interface for user theories (via -P option); actual
  1574 document preparation based on (PDF)LaTeX is available as well (for
  1575 new-style theories only); see isatool doc system for more information;
  1576 
  1577 * native support for Proof General, both for classic Isabelle and
  1578 Isabelle/Isar;
  1579 
  1580 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1581 using the graph browser tool;
  1582 
  1583 * Isabelle manuals now also available as PDF;
  1584 
  1585 * theory loader rewritten from scratch (may not be fully
  1586 bug-compatible); old loadpath variable has been replaced by show_path,
  1587 add_path, del_path, reset_path functions; new operations such as
  1588 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1589 isatool doc ref);
  1590 
  1591 * improved isatool install: option -k creates KDE application icon,
  1592 option -p DIR installs standalone binaries;
  1593 
  1594 * added ML_PLATFORM setting (useful for cross-platform installations);
  1595 more robust handling of platform specific ML images for SML/NJ;
  1596 
  1597 * the settings environment is now statically scoped, i.e. it is never
  1598 created again in sub-processes invoked from isabelle, isatool, or
  1599 Isabelle;
  1600 
  1601 * path element specification '~~' refers to '$ISABELLE_HOME';
  1602 
  1603 * in locales, the "assumes" and "defines" parts may be omitted if
  1604 empty;
  1605 
  1606 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1607 long arrows);
  1608 
  1609 * new print_mode "HTML";
  1610 
  1611 * new flag show_tags controls display of tags of theorems (which are
  1612 basically just comments that may be attached by some tools);
  1613 
  1614 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1615 mode and goal output format:
  1616 
  1617 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1618 244c244
  1619 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1620 ---
  1621 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1622 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1623 181c181
  1624 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1625 ---
  1626 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1627 
  1628 * function bind_thms stores lists of theorems (cf. bind_thm);
  1629 
  1630 * new shorthand tactics ftac, eatac, datac, fatac;
  1631 
  1632 * qed (and friends) now accept "" as result name; in that case the
  1633 theorem is not stored, but proper checks and presentation of the
  1634 result still apply;
  1635 
  1636 * theorem database now also indexes constants "Trueprop", "all",
  1637 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1638 
  1639 
  1640 *** HOL ***
  1641 
  1642 ** HOL arithmetic **
  1643 
  1644 * There are now decision procedures for linear arithmetic over nat and
  1645 int:
  1646 
  1647 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1648 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1649 are treated as atomic; subformulae not involving type `nat' or `int'
  1650 are ignored; quantified subformulae are ignored unless they are
  1651 positive universal or negative existential. The tactic has to be
  1652 invoked by hand and can be a little bit slow. In particular, the
  1653 running time is exponential in the number of occurrences of `min' and
  1654 `max', and `-' on `nat'.
  1655 
  1656 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1657 (negated) (in)equalities among the premises and the conclusion into
  1658 account (i.e. no compound formulae) and does not know about `min' and
  1659 `max', and `-' on `nat'. It is fast and is used automatically by the
  1660 simplifier.
  1661 
  1662 NB: At the moment, these decision procedures do not cope with mixed
  1663 nat/int formulae where the two parts interact, such as `m < n ==>
  1664 int(m) < int(n)'.
  1665 
  1666 * HOL/Numeral provides a generic theory of numerals (encoded
  1667 efficiently as bit strings); setup for types nat/int/real is in place;
  1668 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1669 int, existing theories and proof scripts may require a few additional
  1670 type constraints;
  1671 
  1672 * integer division and remainder can now be performed on constant
  1673 arguments;
  1674 
  1675 * many properties of integer multiplication, division and remainder
  1676 are now available;
  1677 
  1678 * An interface to the Stanford Validity Checker (SVC) is available through the
  1679 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1680 are proved automatically.  SVC must be installed separately, and its results
  1681 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1682 invocation of the underlying oracle).  For SVC see
  1683   http://verify.stanford.edu/SVC
  1684 
  1685 * IsaMakefile: the HOL-Real target now builds an actual image;
  1686 
  1687 
  1688 ** HOL misc **
  1689 
  1690 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1691 (in Isabelle/Isar) -- by Gertrud Bauer;
  1692 
  1693 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1694 analysis for assembly languages with subtypes;
  1695 
  1696 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1697 -- avoids syntactic ambiguities and treats state, transition, and
  1698 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1699 changed syntax and (many) tactics;
  1700 
  1701 * HOL/inductive: Now also handles more general introduction rules such
  1702   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1703   theorems are now maintained within the theory (maintained via the
  1704   "mono" attribute);
  1705 
  1706 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1707   (using function types) such as
  1708 
  1709   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1710 
  1711 * HOL/record: record_simproc (part of the default simpset) takes care
  1712 of selectors applied to updated records; record_split_tac is no longer
  1713 part of the default claset; update_defs may now be removed from the
  1714 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1715 
  1716   claset_ref () := claset() addSWrapper record_split_wrapper;
  1717   Delsimprocs [record_simproc]
  1718 
  1719 * HOL/typedef: fixed type inference for representing set; type
  1720 arguments now have to occur explicitly on the rhs as type constraints;
  1721 
  1722 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1723 names rather than an ML expression;
  1724 
  1725 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1726 supplied later.  Program schemes can be defined, such as
  1727     "While B C s = (if B s then While B C (C s) else s)"
  1728 where the well-founded relation can be chosen after B and C have been given.
  1729 
  1730 * HOL/List: the constructors of type list are now Nil and Cons;
  1731 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1732 course, ML tools referring to List.list.op # etc. have to be adapted;
  1733 
  1734 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1735 disabled by default; run isabelle with option -m HOL to get back to
  1736 the original Gordon/HOL-style output;
  1737 
  1738 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1739 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1740 
  1741 * HOL basic syntax simplified (more orthogonal): all variants of
  1742 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1743 Eps operator is provided as well: "SOME x. P[x]";
  1744 
  1745 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1746 
  1747 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1748 thus available for user theories;
  1749 
  1750 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1751 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1752 time;
  1753 
  1754 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1755 several times and then mp;
  1756 
  1757 
  1758 *** LK ***
  1759 
  1760 * the notation <<...>> is now available as a notation for sequences of
  1761 formulas;
  1762 
  1763 * the simplifier is now installed
  1764 
  1765 * the axiom system has been generalized (thanks to Soren Heilmann)
  1766 
  1767 * the classical reasoner now has a default rule database
  1768 
  1769 
  1770 *** ZF ***
  1771 
  1772 * new primrec section allows primitive recursive functions to be given
  1773 directly (as in HOL) over datatypes and the natural numbers;
  1774 
  1775 * new tactics induct_tac and exhaust_tac for induction (or case
  1776 analysis) over datatypes and the natural numbers;
  1777 
  1778 * the datatype declaration of type T now defines the recursor T_rec;
  1779 
  1780 * simplification automatically does freeness reasoning for datatype
  1781 constructors;
  1782 
  1783 * automatic type-inference, with AddTCs command to insert new
  1784 type-checking rules;
  1785 
  1786 * datatype introduction rules are now added as Safe Introduction rules
  1787 to the claset;
  1788 
  1789 * the syntax "if P then x else y" is now available in addition to
  1790 if(P,x,y);
  1791 
  1792 
  1793 *** Internal programming interfaces ***
  1794 
  1795 * tuned simplifier trace output; new flag debug_simp;
  1796 
  1797 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1798 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1799 
  1800 * AxClass.axclass_tac lost the theory argument;
  1801 
  1802 * tuned current_goals_markers semantics: begin / end goal avoids
  1803 printing empty lines;
  1804 
  1805 * removed prs and prs_fn hook, which was broken because it did not
  1806 include \n in its semantics, forcing writeln to add one
  1807 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1808 string -> unit if you really want to output text without newline;
  1809 
  1810 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1811 plain output, interface builders may have to enable 'isabelle_font'
  1812 mode to get Isabelle font glyphs as before;
  1813 
  1814 * refined token_translation interface; INCOMPATIBILITY: output length
  1815 now of type real instead of int;
  1816 
  1817 * theory loader actions may be traced via new ThyInfo.add_hook
  1818 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1819 your own database of information attached to *whole* theories -- as
  1820 opposed to intra-theory data slots offered via TheoryDataFun;
  1821 
  1822 * proper handling of dangling sort hypotheses (at last!);
  1823 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1824 extra sort hypotheses that can be witnessed from the type signature;
  1825 the force_strip_shyps flag is gone, any remaining shyps are simply
  1826 left in the theorem (with a warning issued by strip_shyps_warning);
  1827 
  1828 
  1829 
  1830 New in Isabelle98-1 (October 1998)
  1831 ----------------------------------
  1832 
  1833 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1834 
  1835 * several changes of automated proof tools;
  1836 
  1837 * HOL: major changes to the inductive and datatype packages, including
  1838 some minor incompatibilities of theory syntax;
  1839 
  1840 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1841 called `inj_on';
  1842 
  1843 * HOL: removed duplicate thms in Arith:
  1844   less_imp_add_less  should be replaced by  trans_less_add1
  1845   le_imp_add_le      should be replaced by  trans_le_add1
  1846 
  1847 * HOL: unary minus is now overloaded (new type constraints may be
  1848 required);
  1849 
  1850 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1851 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1852 now taken as an integer constant.
  1853 
  1854 * Pure: ML function 'theory_of' renamed to 'theory';
  1855 
  1856 
  1857 *** Proof tools ***
  1858 
  1859 * Simplifier:
  1860   1. Asm_full_simp_tac is now more aggressive.
  1861      1. It will sometimes reorient premises if that increases their power to
  1862         simplify.
  1863      2. It does no longer proceed strictly from left to right but may also
  1864         rotate premises to achieve further simplification.
  1865      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1866      old Asm_full_simp_tac in that it does not rotate premises.
  1867   2. The simplifier now knows a little bit about nat-arithmetic.
  1868 
  1869 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1870 allows for selected deletion of wrappers, by introduction of names for
  1871 wrapper functionals.  This implies that addbefore, addSbefore,
  1872 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1873 and that adding two tactics with the same name overwrites the first
  1874 one (emitting a warning).
  1875   type wrapper = (int -> tactic) -> (int -> tactic)
  1876   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1877   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1878   delWrapper, delSWrapper: claset *  string            -> claset
  1879   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1880 
  1881 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1882 semantics; addbefore now affects only the unsafe part of step_tac
  1883 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1884 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1885 by Force_tac;
  1886 
  1887 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1888 compWrapper; added safe wrapper (and access functions for it);
  1889 
  1890 * HOL/split_all_tac is now much faster and fails if there is nothing
  1891 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1892 and the names of the automatically generated variables have changed.
  1893 split_all_tac has moved within claset() from unsafe wrappers to safe
  1894 wrappers, which means that !!-bound variables are split much more
  1895 aggressively, and safe_tac and clarify_tac now split such variables.
  1896 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1897 Note: the same holds for record_split_tac, which does the job of
  1898 split_all_tac for record fields.
  1899 
  1900 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1901 permanently to the default simpset using Addsplits just like
  1902 Addsimps. They can be removed via Delsplits just like
  1903 Delsimps. Lower-case versions are also available.
  1904 
  1905 * HOL/Simplifier: The rule split_if is now part of the default
  1906 simpset. This means that the simplifier will eliminate all occurrences
  1907 of if-then-else in the conclusion of a goal. To prevent this, you can
  1908 either remove split_if completely from the default simpset by
  1909 `Delsplits [split_if]' or remove it in a specific call of the
  1910 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1911 other case splitting rules to/from the default simpset: every datatype
  1912 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1913 t is the name of the datatype).
  1914 
  1915 * Classical reasoner / Simplifier combination: new force_tac (and
  1916 derivatives Force_tac, force) combines rewriting and classical
  1917 reasoning (and whatever other tools) similarly to auto_tac, but is
  1918 aimed to solve the given subgoal completely.
  1919 
  1920 
  1921 *** General ***
  1922 
  1923 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1924 and `goalw': the theory is no longer needed as an explicit argument -
  1925 the current theory context is used; assumptions are no longer returned
  1926 at the ML-level unless one of them starts with ==> or !!; it is
  1927 recommended to convert to these new commands using isatool fixgoal
  1928 (backup your sources first!);
  1929 
  1930 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1931 the current theory context, and 'theory' to lookup stored theories;
  1932 
  1933 * new theory section 'locale' for declaring constants, assumptions and
  1934 definitions that have local scope;
  1935 
  1936 * new theory section 'nonterminals' for purely syntactic types;
  1937 
  1938 * new theory section 'setup' for generic ML setup functions
  1939 (e.g. package initialization);
  1940 
  1941 * the distribution now includes Isabelle icons: see
  1942 lib/logo/isabelle-{small,tiny}.xpm;
  1943 
  1944 * isatool install - install binaries with absolute references to
  1945 ISABELLE_HOME/bin;
  1946 
  1947 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1948 
  1949 * print mode 'emacs' reserved for Isamode;
  1950 
  1951 * support multiple print (ast) translations per constant name;
  1952 
  1953 * theorems involving oracles are now printed with a suffixed [!];
  1954 
  1955 
  1956 *** HOL ***
  1957 
  1958 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1959 
  1960 * HOL/inductive package reorganized and improved: now supports mutual
  1961 definitions such as
  1962 
  1963   inductive EVEN ODD
  1964     intrs
  1965       null "0 : EVEN"
  1966       oddI "n : EVEN ==> Suc n : ODD"
  1967       evenI "n : ODD ==> Suc n : EVEN"
  1968 
  1969 new theorem list "elims" contains an elimination rule for each of the
  1970 recursive sets; inductive definitions now handle disjunctive premises
  1971 correctly (also ZF);
  1972 
  1973 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1974 "mutual_induct" no longer exists - the induction rule is always
  1975 contained in "induct";
  1976 
  1977 
  1978 * HOL/datatype package re-implemented and greatly improved: now
  1979 supports mutually recursive datatypes such as
  1980 
  1981   datatype
  1982     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1983             | SUM ('a aexp) ('a aexp)
  1984             | DIFF ('a aexp) ('a aexp)
  1985             | NUM 'a
  1986   and
  1987     'a bexp = LESS ('a aexp) ('a aexp)
  1988             | AND ('a bexp) ('a bexp)
  1989             | OR ('a bexp) ('a bexp)
  1990 
  1991 as well as indirectly recursive datatypes such as
  1992 
  1993   datatype
  1994     ('a, 'b) term = Var 'a
  1995                   | App 'b ((('a, 'b) term) list)
  1996 
  1997 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1998 induction on mutually / indirectly recursive datatypes.
  1999 
  2000 Primrec equations are now stored in theory and can be accessed via
  2001 <function_name>.simps.
  2002 
  2003 INCOMPATIBILITIES:
  2004 
  2005   - Theories using datatypes must now have theory Datatype as an
  2006     ancestor.
  2007   - The specific <typename>.induct_tac no longer exists - use the
  2008     generic induct_tac instead.
  2009   - natE has been renamed to nat.exhaust - use exhaust_tac
  2010     instead of res_inst_tac ... natE. Note that the variable
  2011     names in nat.exhaust differ from the names in natE, this
  2012     may cause some "fragile" proofs to fail.
  2013   - The theorems split_<typename>_case and split_<typename>_case_asm
  2014     have been renamed to <typename>.split and <typename>.split_asm.
  2015   - Since default sorts of type variables are now handled correctly,
  2016     some datatype definitions may have to be annotated with explicit
  2017     sort constraints.
  2018   - Primrec definitions no longer require function name and type
  2019     of recursive argument.
  2020 
  2021 Consider using isatool fixdatatype to adapt your theories and proof
  2022 scripts to the new package (backup your sources first!).
  2023 
  2024 
  2025 * HOL/record package: considerably improved implementation; now
  2026 includes concrete syntax for record types, terms, updates; theorems
  2027 for surjective pairing and splitting !!-bound record variables; proof
  2028 support is as follows:
  2029 
  2030   1) standard conversions (selectors or updates applied to record
  2031 constructor terms) are part of the standard simpset;
  2032 
  2033   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2034 made part of standard simpset and claset via addIffs;
  2035 
  2036   3) a tactic for record field splitting (record_split_tac) is part of
  2037 the standard claset (addSWrapper);
  2038 
  2039 To get a better idea about these rules you may retrieve them via
  2040 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2041 the name of your record type.
  2042 
  2043 The split tactic 3) conceptually simplifies by the following rule:
  2044 
  2045   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2046 
  2047 Thus any record variable that is bound by meta-all will automatically
  2048 blow up into some record constructor term, consequently the
  2049 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2050 solve record problems automatically.
  2051 
  2052 
  2053 * reorganized the main HOL image: HOL/Integ and String loaded by
  2054 default; theory Main includes everything;
  2055 
  2056 * automatic simplification of integer sums and comparisons, using cancellation;
  2057 
  2058 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2059 
  2060 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2061 
  2062 * many new identities for unions, intersections, set difference, etc.;
  2063 
  2064 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2065 called split_if, split_split, split_sum_case and split_nat_case (to go
  2066 with add/delsplits);
  2067 
  2068 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2069 (?x::unit) = (); this is made part of the default simpset, which COULD
  2070 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2071 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2072 unit_abs_eta_conv is added in order to counter the effect of
  2073 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2074 %u.f();
  2075 
  2076 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2077 makes more sense);
  2078 
  2079 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2080   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2081   disjointness reasoning but breaking a few old proofs.
  2082 
  2083 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2084 to 'converse' from 'inverse' (for compatibility with ZF and some
  2085 literature);
  2086 
  2087 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2088 the well-founded relation;
  2089 
  2090 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2091     Compl A.  The "Compl" syntax remains available as input syntax for this
  2092     release ONLY.
  2093 
  2094 * HOL/Update: new theory of function updates:
  2095     f(a:=b) == %x. if x=a then b else f x
  2096 may also be iterated as in f(a:=b,c:=d,...);
  2097 
  2098 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2099 
  2100 * HOL/List:
  2101   - new function list_update written xs[i:=v] that updates the i-th
  2102     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2103   - new function `upt' written [i..j(] which generates the list
  2104     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2105     bound write [i..j], which is a shorthand for [i..j+1(].
  2106   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2107 
  2108 * HOL/Arith:
  2109   - removed 'pred' (predecessor) function;
  2110   - generalized some theorems about n-1;
  2111   - many new laws about "div" and "mod";
  2112   - new laws about greatest common divisors (see theory ex/Primes);
  2113 
  2114 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2115 instead of "inverse";
  2116 
  2117 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2118   of the multiset ordering;
  2119 
  2120 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2121   (not included by default);
  2122 
  2123 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2124 
  2125 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2126   programs, i.e. different program variables may have different types.
  2127 
  2128 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2129   [previously, this check worked only if the rewrite rule was unconditional]
  2130   Now rew can involve either definitions or equalities (either == or =).
  2131 
  2132 
  2133 *** ZF ***
  2134 
  2135 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2136   only the theorems proved on ZF.ML;
  2137 
  2138 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2139   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2140   disjointness reasoning but breaking a few old proofs.
  2141 
  2142 * ZF/Update: new theory of function updates
  2143     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2144   may also be iterated as in f(a:=b,c:=d,...);
  2145 
  2146 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2147 
  2148 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2149   [previously, this check worked only if the rewrite rule was unconditional]
  2150   Now rew can involve either definitions or equalities (either == or =).
  2151 
  2152 * case_tac provided for compatibility with HOL
  2153     (like the old excluded_middle_tac, but with subgoals swapped)
  2154 
  2155 
  2156 *** Internal programming interfaces ***
  2157 
  2158 * Pure: several new basic modules made available for general use, see
  2159 also src/Pure/README;
  2160 
  2161 * improved the theory data mechanism to support encapsulation (data
  2162 kind name replaced by private Object.kind, acting as authorization
  2163 key); new type-safe user interface via functor TheoryDataFun; generic
  2164 print_data function becomes basically useless;
  2165 
  2166 * removed global_names compatibility flag -- all theory declarations
  2167 are qualified by default;
  2168 
  2169 * module Pure/Syntax now offers quote / antiquote translation
  2170 functions (useful for Hoare logic etc. with implicit dependencies);
  2171 see HOL/ex/Antiquote for an example use;
  2172 
  2173 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2174 cterm -> thm;
  2175 
  2176 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2177 subgoal;
  2178 
  2179 * Display.print_goals function moved to Locale.print_goals;
  2180 
  2181 * standard print function for goals supports current_goals_markers
  2182 variable for marking begin of proof, end of proof, start of goal; the
  2183 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2184 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2185 for example;
  2186 
  2187 
  2188 
  2189 New in Isabelle98 (January 1998)
  2190 --------------------------------
  2191 
  2192 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2193 
  2194 * changed lexical syntax of terms / types: dots made part of long
  2195 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2196 
  2197 * simpset (and claset) reference variable replaced by functions
  2198 simpset / simpset_ref;
  2199 
  2200 * no longer supports theory aliases (via merge) and non-trivial
  2201 implicit merge of thms' signatures;
  2202 
  2203 * most internal names of constants changed due to qualified names;
  2204 
  2205 * changed Pure/Sequence interface (see Pure/seq.ML);
  2206 
  2207 
  2208 *** General Changes ***
  2209 
  2210 * hierachically structured name spaces (for consts, types, axms, thms
  2211 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2212 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2213 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2214 long_names for fully qualified output names; NOTE: ML programs
  2215 (special tactics, packages etc.) referring to internal names may have
  2216 to be adapted to cope with fully qualified names; in case of severe
  2217 backward campatibility problems try setting 'global_names' at compile
  2218 time to have enrything declared within a flat name space; one may also
  2219 fine tune name declarations in theories via the 'global' and 'local'
  2220 section;
  2221 
  2222 * reimplemented the implicit simpset and claset using the new anytype
  2223 data filed in signatures; references simpset:simpset ref etc. are
  2224 replaced by functions simpset:unit->simpset and
  2225 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2226 to patch your ML files accordingly;
  2227 
  2228 * HTML output now includes theory graph data for display with Java
  2229 applet or isatool browser; data generated automatically via isatool
  2230 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2231 
  2232 * defs may now be conditional; improved rewrite_goals_tac to handle
  2233 conditional equations;
  2234 
  2235 * defs now admits additional type arguments, using TYPE('a) syntax;
  2236 
  2237 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2238 creates a new theory node; implicit merge of thms' signatures is
  2239 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2240 transfer:theory->thm->thm in (rare) cases;
  2241 
  2242 * improved handling of draft signatures / theories; draft thms (and
  2243 ctyps, cterms) are automatically promoted to real ones;
  2244 
  2245 * slightly changed interfaces for oracles: admit many per theory, named
  2246 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2247 
  2248 * print_goals: optional output of const types (set show_consts and
  2249 show_types);
  2250 
  2251 * improved output of warnings (###) and errors (***);
  2252 
  2253 * subgoal_tac displays a warning if the new subgoal has type variables;
  2254 
  2255 * removed old README and Makefiles;
  2256 
  2257 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2258 
  2259 * removed obsolete init_pps and init_database;
  2260 
  2261 * deleted the obsolete tactical STATE, which was declared by
  2262     fun STATE tacfun st = tacfun st st;
  2263 
  2264 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2265 (which abbreviates $HOME);
  2266 
  2267 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2268 use isatool fixseq to adapt your ML programs (this works for fully
  2269 qualified references to the Sequence structure only!);
  2270 
  2271 * use_thy no longer requires writable current directory; it always
  2272 reloads .ML *and* .thy file, if either one is out of date;
  2273 
  2274 
  2275 *** Classical Reasoner ***
  2276 
  2277 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2278 tactics that use classical reasoning to simplify a subgoal without
  2279 splitting it into several subgoals;
  2280 
  2281 * Safe_tac: like safe_tac but uses the default claset;
  2282 
  2283 
  2284 *** Simplifier ***
  2285 
  2286 * added simplification meta rules:
  2287     (asm_)(full_)simplify: simpset -> thm -> thm;
  2288 
  2289 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2290 logics (again);
  2291 
  2292 * added prems argument to simplification procedures;
  2293 
  2294 * HOL, FOL, ZF: added infix function `addsplits':
  2295   instead of `<simpset> setloop (split_tac <thms>)'
  2296   you can simply write `<simpset> addsplits <thms>'
  2297 
  2298 
  2299 *** Syntax ***
  2300 
  2301 * TYPE('a) syntax for type reflection terms;
  2302 
  2303 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2304 
  2305 * pretty printer: changed order of mixfix annotation preference (again!);
  2306 
  2307 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2308 
  2309 
  2310 *** HOL ***
  2311 
  2312 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2313   with `addloop' of the simplifier to faciliate case splitting in premises.
  2314 
  2315 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2316 
  2317 * HOL/Auth: new protocol proofs including some for the Internet
  2318   protocol TLS;
  2319 
  2320 * HOL/Map: new theory of `maps' a la VDM;
  2321 
  2322 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2323 cancelling out common nat summands from =, <, <= (in)equalities, or
  2324 differences; simplification procedures nat_cancel_factor for
  2325 cancelling common factor from =, <, <= (in)equalities over natural
  2326 sums; nat_cancel contains both kinds of procedures, it is installed by
  2327 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2328 
  2329 * HOL/simplifier: terms of the form
  2330   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2331   are rewritten to
  2332   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2333   and those of the form
  2334   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2335   are rewritten to
  2336   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2337 
  2338 * HOL/datatype
  2339   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2340 
  2341   P(t_case f1 ... fn x) =
  2342      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2343         ...
  2344        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2345      )
  2346 
  2347   and a theorem `split_t_case_asm' of the form
  2348 
  2349   P(t_case f1 ... fn x) =
  2350     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2351         ...
  2352        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2353      )
  2354   which can be added to a simpset via `addsplits'. The existing theorems
  2355   expand_list_case and expand_option_case have been renamed to
  2356   split_list_case and split_option_case.
  2357 
  2358 * HOL/Arithmetic:
  2359   - `pred n' is automatically converted to `n-1'.
  2360     Users are strongly encouraged not to use `pred' any longer,
  2361     because it will disappear altogether at some point.
  2362   - Users are strongly encouraged to write "0 < n" rather than
  2363     "n ~= 0". Theorems and proof tools have been modified towards this
  2364     `standard'.
  2365 
  2366 * HOL/Lists:
  2367   the function "set_of_list" has been renamed "set" (and its theorems too);
  2368   the function "nth" now takes its arguments in the reverse order and
  2369   has acquired the infix notation "!" as in "xs!n".
  2370 
  2371 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2372 
  2373 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2374   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2375 
  2376 * HOL/record: extensible records with schematic structural subtyping
  2377 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2378 still lacks various theorems and concrete record syntax;
  2379 
  2380 
  2381 *** HOLCF ***
  2382 
  2383 * removed "axioms" and "generated by" sections;
  2384 
  2385 * replaced "ops" section by extended "consts" section, which is capable of
  2386   handling the continuous function space "->" directly;
  2387 
  2388 * domain package:
  2389   . proves theorems immediately and stores them in the theory,
  2390   . creates hierachical name space,
  2391   . now uses normal mixfix annotations (instead of cinfix...),
  2392   . minor changes to some names and values (for consistency),
  2393   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2394   . separator between mutual domain defs: changed "," to "and",
  2395   . improved handling of sort constraints;  now they have to
  2396     appear on the left-hand side of the equations only;
  2397 
  2398 * fixed LAM <x,y,zs>.b syntax;
  2399 
  2400 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2401 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2402 
  2403 
  2404 *** FOL and ZF ***
  2405 
  2406 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2407   with `addloop' of the simplifier to faciliate case splitting in premises.
  2408 
  2409 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2410 in HOL, they strip ALL and --> from proved theorems;
  2411 
  2412 
  2413 
  2414 New in Isabelle94-8 (May 1997)
  2415 ------------------------------
  2416 
  2417 *** General Changes ***
  2418 
  2419 * new utilities to build / run / maintain Isabelle etc. (in parts
  2420 still somewhat experimental); old Makefiles etc. still functional;
  2421 
  2422 * new 'Isabelle System Manual';
  2423 
  2424 * INSTALL text, together with ./configure and ./build scripts;
  2425 
  2426 * reimplemented type inference for greater efficiency, better error
  2427 messages and clean internal interface;
  2428 
  2429 * prlim command for dealing with lots of subgoals (an easier way of
  2430 setting goals_limit);
  2431 
  2432 
  2433 *** Syntax ***
  2434 
  2435 * supports alternative (named) syntax tables (parser and pretty
  2436 printer); internal interface is provided by add_modesyntax(_i);
  2437 
  2438 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2439 be used in conjunction with the Isabelle symbol font; uses the
  2440 "symbols" syntax table;
  2441 
  2442 * added token_translation interface (may translate name tokens in
  2443 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2444 the current print_mode); IMPORTANT: user print translation functions
  2445 are responsible for marking newly introduced bounds
  2446 (Syntax.mark_boundT);
  2447 
  2448 * token translations for modes "xterm" and "xterm_color" that display
  2449 names in bold, underline etc. or colors (which requires a color
  2450 version of xterm);
  2451 
  2452 * infixes may now be declared with names independent of their syntax;
  2453 
  2454 * added typed_print_translation (like print_translation, but may
  2455 access type of constant);
  2456 
  2457 
  2458 *** Classical Reasoner ***
  2459 
  2460 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2461 some limitations.  Blast_tac...
  2462   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2463   + ignores elimination rules that don't have the correct format
  2464         (the conclusion MUST be a formula variable)
  2465   + ignores types, which can make HOL proofs fail
  2466   + rules must not require higher-order unification, e.g. apply_type in ZF
  2467     [message "Function Var's argument not a bound variable" relates to this]
  2468   + its proof strategy is more general but can actually be slower
  2469 
  2470 * substitution with equality assumptions no longer permutes other
  2471 assumptions;
  2472 
  2473 * minor changes in semantics of addafter (now called addaltern); renamed
  2474 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2475 (and access functions for it);
  2476 
  2477 * improved combination of classical reasoner and simplifier:
  2478   + functions for handling clasimpsets
  2479   + improvement of addss: now the simplifier is called _after_ the
  2480     safe steps.
  2481   + safe variant of addss called addSss: uses safe simplifications
  2482     _during_ the safe steps. It is more complete as it allows multiple
  2483     instantiations of unknowns (e.g. with slow_tac).
  2484 
  2485 *** Simplifier ***
  2486 
  2487 * added interface for simplification procedures (functions that
  2488 produce *proven* rewrite rules on the fly, depending on current
  2489 redex);
  2490 
  2491 * ordering on terms as parameter (used for ordered rewriting);
  2492 
  2493 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2494 
  2495 * the solver is now split into a safe and an unsafe part.
  2496 This should be invisible for the normal user, except that the
  2497 functions setsolver and addsolver have been renamed to setSolver and
  2498 addSolver; added safe_asm_full_simp_tac;
  2499 
  2500 
  2501 *** HOL ***
  2502 
  2503 * a generic induction tactic `induct_tac' which works for all datatypes and
  2504 also for type `nat';
  2505 
  2506 * a generic case distinction tactic `exhaust_tac' which works for all
  2507 datatypes and also for type `nat';
  2508 
  2509 * each datatype comes with a function `size';
  2510 
  2511 * patterns in case expressions allow tuple patterns as arguments to
  2512 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2513 
  2514 * primrec now also works with type nat;
  2515 
  2516 * recdef: a new declaration form, allows general recursive functions to be
  2517 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2518 
  2519 * the constant for negation has been renamed from "not" to "Not" to
  2520 harmonize with FOL, ZF, LK, etc.;
  2521 
  2522 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2523 infinite lists;
  2524 
  2525 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2526 
  2527 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2528 problems in commutative rings, using axiomatic type classes for + and *;
  2529 
  2530 * more examples in HOL/MiniML and HOL/Auth;
  2531 
  2532 * more default rewrite rules for quantifiers, union/intersection;
  2533 
  2534 * a new constant `arbitrary == @x.False';
  2535 
  2536 * HOLCF/IOA replaces old HOL/IOA;
  2537 
  2538 * HOLCF changes: derived all rules and arities
  2539   + axiomatic type classes instead of classes
  2540   + typedef instead of faking type definitions
  2541   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2542   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2543   + eliminated the types void, one, tr
  2544   + use unit lift and bool lift (with translations) instead of one and tr
  2545   + eliminated blift from Lift3.thy (use Def instead of blift)
  2546   all eliminated rules are derived as theorems --> no visible changes ;
  2547 
  2548 
  2549 *** ZF ***
  2550 
  2551 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2552 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2553 as ZF_cs addSIs [equalityI];
  2554 
  2555 
  2556 
  2557 New in Isabelle94-7 (November 96)
  2558 ---------------------------------
  2559 
  2560 * allowing negative levels (as offsets) in prlev and choplev;
  2561 
  2562 * super-linear speedup for large simplifications;
  2563 
  2564 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2565 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2566 FAIL); can suppress it using the command Delsimps (ex_simps @
  2567 all_simps); De Morgan laws are also now included, by default;
  2568 
  2569 * improved printing of ==>  :  ~:
  2570 
  2571 * new object-logic "Sequents" adds linear logic, while replacing LK
  2572 and Modal (thanks to Sara Kalvala);
  2573 
  2574 * HOL/Auth: correctness proofs for authentication protocols;
  2575 
  2576 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2577 examples on HOL/Auth);
  2578 
  2579 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2580 the rewriter and classical reasoner simultaneously;
  2581 
  2582 * function uresult no longer returns theorems in "standard" format;
  2583 regain previous version by: val uresult = standard o uresult;
  2584 
  2585 
  2586 
  2587 New in Isabelle94-6
  2588 -------------------
  2589 
  2590 * oracles -- these establish an interface between Isabelle and trusted
  2591 external reasoners, which may deliver results as theorems;
  2592 
  2593 * proof objects (in particular record all uses of oracles);
  2594 
  2595 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2596 
  2597 * "constdefs" section in theory files;
  2598 
  2599 * "primrec" section (HOL) no longer requires names;
  2600 
  2601 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2602 
  2603 
  2604 
  2605 New in Isabelle94-5
  2606 -------------------
  2607 
  2608 * reduced space requirements;
  2609 
  2610 * automatic HTML generation from theories;
  2611 
  2612 * theory files no longer require "..." (quotes) around most types;
  2613 
  2614 * new examples, including two proofs of the Church-Rosser theorem;
  2615 
  2616 * non-curried (1994) version of HOL is no longer distributed;
  2617 
  2618 
  2619 
  2620 New in Isabelle94-4
  2621 -------------------
  2622 
  2623 * greatly reduced space requirements;
  2624 
  2625 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2626 
  2627 * searchable theorem database (see the section "Retrieving theorems" on
  2628 page 8 of the Reference Manual);
  2629 
  2630 * new examples, including Grabczewski's monumental case study of the
  2631 Axiom of Choice;
  2632 
  2633 * The previous version of HOL renamed to Old_HOL;
  2634 
  2635 * The new version of HOL (previously called CHOL) uses a curried syntax
  2636 for functions.  Application looks like f a b instead of f(a,b);
  2637 
  2638 * Mutually recursive inductive definitions finally work in HOL;
  2639 
  2640 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2641 translates to the operator "split";
  2642 
  2643 
  2644 
  2645 New in Isabelle94-3
  2646 -------------------
  2647 
  2648 * new infix operator, addss, allowing the classical reasoner to
  2649 perform simplification at each step of its search.  Example:
  2650         fast_tac (cs addss ss)
  2651 
  2652 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2653 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2654 look like (a,b) instead of <a,b>;
  2655 
  2656 * PLEASE NOTE: CHOL will eventually replace HOL!
  2657 
  2658 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2659 It translates to the operator "split".  A new theory of integers is available;
  2660 
  2661 * In ZF, integer numerals now denote two's-complement binary integers.
  2662 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2663 
  2664 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2665 of the Axiom of Choice;
  2666 
  2667 
  2668 
  2669 New in Isabelle94-2
  2670 -------------------
  2671 
  2672 * Significantly faster resolution;
  2673 
  2674 * the different sections in a .thy file can now be mixed and repeated
  2675 freely;
  2676 
  2677 * Database of theorems for FOL, HOL and ZF.  New
  2678 commands including qed, qed_goal and bind_thm store theorems in the database.
  2679 
  2680 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2681 a given theory (thms_of), or find out what theory a theorem was proved in
  2682 (theory_of_thm);
  2683 
  2684 * Bugs fixed in the inductive definition and datatype packages;
  2685 
  2686 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2687 and HOL_dup_cs obsolete;
  2688 
  2689 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2690 have been removed;
  2691 
  2692 * Simpler definition of function space in ZF;
  2693 
  2694 * new results about cardinal and ordinal arithmetic in ZF;
  2695 
  2696 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2697 types;
  2698 
  2699 
  2700 $Id$