NEWS
author wenzelm
Wed Jul 06 10:41:51 2005 +0200 (2005-07-06)
changeset 16717 710a7a7a2b65
parent 16690 b8b2579a2509
child 16718 70c94b82c556
permissions -rw-r--r--
isatool fixheaders;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryN>
    13   uses <file1> ... <fileM>
    14   begin
    15 
    16 where the 'uses' part is optional.  The previous syntax
    17 
    18   theory <name> = <theory1> + ... + <theoryN>:
    19 
    20 will disappear in the next release.  Use isatool fixheaders to convert
    21 existing theory files.  Note that there is no change in ancient
    22 non-Isar theories.
    23 
    24 * Theory loader: parent theories can now also be referred to via
    25 relative and absolute paths.
    26 
    27 * Improved version of thms_containing searches for a list of criteria
    28 instead of a list of constants. Known criteria are: intro, elim, dest,
    29 name:string, simp:term, and any term. Criteria can be preceded by '-'
    30 to select theorems that do not match. Intro, elim, dest select
    31 theorems that match the current goal, name:s selects theorems whose
    32 fully qualified name contain s, and simp:term selects all
    33 simplification rules whose lhs match term.  Any other term is
    34 interpreted as pattern and selects all theorems matching the
    35 pattern. Available in ProofGeneral under 'ProofGeneral -> Find
    36 Theorems' or C-c C-f.  Example:
    37 
    38   C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
    39 
    40 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
    41 matching the current goal as introduction rule and not having "HOL."
    42 in their name (i.e. not being defined in theory HOL).
    43 
    44 
    45 *** Document preparation ***
    46 
    47 * Commands 'display_drafts' and 'print_drafts' perform simple output
    48 of raw sources.  Only those symbols that do not require additional
    49 LaTeX packages (depending on comments in isabellesym.sty) are
    50 displayed properly, everything else is left verbatim.  isatool display
    51 and isatool print are used as front ends (these are subject to the
    52 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
    53 
    54 * There is now a flag to control hiding of proofs and some other
    55 commands (such as 'ML' or 'parse/print_translation') in document
    56 output.  Hiding is enabled by default, and can be disabled by the
    57 option '-H false' of isatool usedir or by resetting the reference
    58 variable IsarOutput.hide_commands in ML.  Additional commands to be
    59 hidden may be declared using IsarOutput.add_hidden_commands.
    60 
    61 * Several new antiquotation:
    62 
    63   @{term_type term} prints a term with its type annotated;
    64 
    65   @{typeof term} prints the type of a term;
    66 
    67   @{const const} is the same as @{term const}, but checks that the
    68   argument is a known logical constant;
    69 
    70   @{term_style style term} and @{thm_style style thm} print a term or
    71   theorem applying a "style" to it
    72 
    73 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
    74 definitions, equations, inequations etc., 'concl' printing only the
    75 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem9'
    76 to print the specified premise.  TermStyle.add_style provides an ML
    77 interface for introducing further styles.  See also the "LaTeX Sugar"
    78 document practical applications.
    79 
    80 
    81 *** Pure ***
    82 
    83 * Considerably improved version of 'constdefs' command.  Now performs
    84 automatic type-inference of declared constants; additional support for
    85 local structure declarations (cf. locales and HOL records), see also
    86 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
    87 sequential dependencies of definitions within a single 'constdefs'
    88 section; moreover, the declared name needs to be an identifier.  If
    89 all fails, consider to fall back on 'consts' and 'defs' separately.
    90 
    91 * Improved indexed syntax and implicit structures.  First of all,
    92 indexed syntax provides a notational device for subscripted
    93 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    94 expressions.  Secondly, in a local context with structure
    95 declarations, number indexes \<^sub>n or the empty index (default
    96 number 1) refer to a certain fixed variable implicitly; option
    97 show_structs controls printing of implicit structures.  Typical
    98 applications of these concepts involve record types and locales.
    99 
   100 * New command 'no_syntax' removes grammar declarations (and
   101 translations) resulting from the given syntax specification, which is
   102 interpreted in the same manner as for the 'syntax' command.
   103 
   104 * 'Advanced' translation functions (parse_translation etc.) may depend
   105 on the signature of the theory context being presently used for
   106 parsing/printing, see also isar-ref manual.
   107 
   108 * Improved internal renaming of symbolic identifiers -- attach primes
   109 instead of base 26 numbers.
   110 
   111 * New flag show_question_marks controls printing of leading question
   112 marks in schematic variable names.
   113 
   114 * In schematic variable names, *any* symbol following \<^isub> or
   115 \<^isup> is now treated as part of the base name.  For example, the
   116 following works without printing of awkward ".0" indexes:
   117 
   118   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   119     by simp
   120 
   121 * Inner syntax includes (*(*nested*) comments*).
   122 
   123 * Pretty pinter now supports unbreakable blocks, specified in mixfix
   124 annotations as "(00...)".
   125 
   126 * Clear separation of logical types and nonterminals, where the latter
   127 may only occur in 'syntax' specifications or type abbreviations.
   128 Before that distinction was only partially implemented via type class
   129 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   130 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   131 exotic syntax specifications may require further adaption
   132 (e.g. Cube/Base.thy).
   133 
   134 * Removed obsolete type class "logic", use the top sort {} instead.
   135 Note that non-logical types should be declared as 'nonterminals'
   136 rather than 'types'.  INCOMPATIBILITY for new object-logic
   137 specifications.
   138 
   139 * Simplifier: can now control the depth to which conditional rewriting
   140 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   141 Limit.
   142 
   143 * Simplifier: simplification procedures may now take the current
   144 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   145 interface), which is very useful for calling the Simplifier
   146 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   147 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   148 low-level mk_simproc no longer applies Logic.varify internally, to
   149 allow for use in a context of fixed variables.
   150 
   151 * thin_tac now works even if the assumption being deleted contains !!
   152 or ==>.  More generally, erule now works even if the major premise of
   153 the elimination rule contains !! or ==>.
   154 
   155 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   156 from Pure, which contains all common declarations already.  Both
   157 theories are defined via plain Isabelle/Isar .thy files.
   158 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   159 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   160 use isatool fixcpure to adapt your theory and ML sources.
   161 
   162 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   163 selections of theorems in named facts via index ranges.
   164 
   165 * More efficient treatment of intermediate checkpoints in interactive
   166 theory development.
   167 
   168 
   169 *** Locales ***
   170   
   171 * New commands for the interpretation of locale expressions in
   172 theories ('interpretation') and proof contexts ('interpret').  These
   173 take an instantiation of the locale parameters and compute proof
   174 obligations from the instantiated specification.  After the
   175 obligations have been discharged, the instantiated theorems of the
   176 locale are added to the theory or proof context.  Interpretation is
   177 smart in that already active interpretations do not occur in proof
   178 obligations, neither are instantiated theorems stored in duplicate.
   179 Use print_interps to inspect active interpretations of a particular
   180 locale.  For details, see the Isar Reference manual.
   181 
   182 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   183 'interpret' instead.
   184 
   185 * Proper static binding of attribute syntax -- i.e. types / terms /
   186 facts mentioned as arguments are always those of the locale definition
   187 context, independently of the context of later invocations.  Moreover,
   188 locale operations (renaming and type / term instantiation) are applied
   189 to attribute arguments as expected.
   190 
   191 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   192 actual attributes; rare situations may require Attrib.attribute to
   193 embed those attributes into Attrib.src that lack concrete syntax.
   194 Attribute implementations need to cooperate properly with the static
   195 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   196 Attrib.XXX_thm etc. already do the right thing without further
   197 intervention.  Only unusual applications -- such as "where" or "of"
   198 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   199 on the context and the facts involved -- may have to assign parsed
   200 values to argument tokens explicitly.
   201 
   202 * New context element "constrains" adds type constraints to parameters --
   203 there is no logical significance.
   204 
   205 * Context expressions: renaming parameters permits syntax
   206 redeclaration as well.
   207 
   208 * Locale definition: 'includes' now disallowed.
   209 
   210 * Changed parameter management in theorem generation for long goal
   211 statements with 'includes'.  INCOMPATIBILITY: produces a different
   212 theorem statement in rare situations.
   213 
   214 * Attributes 'induct' and 'cases': type or set names may now be
   215 locally fixed variables as well.
   216 
   217 * Antiquotations now provide the option 'locale=NAME' to specify an
   218 alternative context used for evaluating and printing the subsequent
   219 argument, as in @{thm [locale=LC] fold_commute}, for example.
   220 
   221 
   222 *** Provers ***
   223 
   224 * Provers/hypsubst.ML: improved version of the subst method, for
   225 single-step rewriting: it now works in bound variable contexts. New is
   226 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   227 rewrite a different subterm than the original subst method, which is
   228 still available as 'simplesubst'.
   229 
   230 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   231 and quasi orders.
   232 
   233 * Provers/trancl.ML: new transitivity reasoner for transitive and
   234 reflexive-transitive closure of relations.
   235 
   236 * Provers/blast.ML: new reference depth_limit to make blast's depth
   237 limit (previously hard-coded with a value of 20) user-definable.
   238 
   239 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   240 is peformed already.  Object-logics merely need to finish their
   241 initial simpset configuration as before.  INCOMPATIBILITY.
   242 
   243 
   244 *** HOL ***
   245 
   246 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   247 
   248   syntax (epsilon)
   249     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   250 
   251 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   252 and x-symbol; use option '-m epsilon' to get it actually printed.
   253 Moreover, the mathematically important symbolic identifier \<epsilon>
   254 becomes available as variable, constant etc.  INCOMPATIBILITY,
   255 
   256 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   257 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   258 is \<ge>.
   259 
   260 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   261 instead of ":".
   262 
   263 * theory SetInterval: changed the syntax for open intervals:
   264 
   265   Old       New
   266   {..n(}    {..<n}
   267   {)n..}    {n<..}
   268   {m..n(}   {m..<n}
   269   {)m..n}   {m<..n}
   270   {)m..n(}  {m<..<n}
   271 
   272 The old syntax is still supported but will disappear in the next
   273 release.  For conversion use the following Emacs search and replace
   274 patterns (these are not perfect but work quite well):
   275 
   276   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   277   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   278 
   279 * theory Finite_Set: changed the syntax for 'setsum', summation over
   280 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   281 now either "SUM x:A. e" or "\<Sum>x \<in> A. e".
   282 
   283 Some new syntax forms are available:
   284 
   285   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   286   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   287   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   288   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   289 
   290 The latter form "\<Sum>x < k. e" used to be based on a separate
   291 function "Summation", which has been discontinued.
   292 
   293 * theory Finite_Set: in structured induction proofs, the insert case
   294 is now 'case (insert x F)' instead of the old counterintuitive 'case
   295 (insert F x)'.
   296 
   297 * The 'refute' command has been extended to support a much larger
   298 fragment of HOL, including axiomatic type classes, constdefs and
   299 typedefs, inductive datatypes and recursion.
   300 
   301 * Datatype induction via method 'induct' now preserves the name of the
   302 induction variable. For example, when proving P(xs::'a list) by
   303 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   304 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   305 in unstructured proof scripts.
   306 
   307 * Reworked implementation of records.  Improved scalability for
   308 records with many fields, avoiding performance problems for type
   309 inference. Records are no longer composed of nested field types, but
   310 of nested extension types. Therefore the record type only grows linear
   311 in the number of extensions and not in the number of fields.  The
   312 top-level (users) view on records is preserved.  Potential
   313 INCOMPATIBILITY only in strange cases, where the theory depends on the
   314 old record representation. The type generated for a record is called
   315 <record_name>_ext_type.
   316 
   317 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   318 proofs triggered by a record definition or a simproc (if
   319 quick_and_dirty is enabled).  Definitions of large records can take
   320 quite long.
   321 
   322 New simproc record_upd_simproc for simplification of multiple record
   323 updates enabled by default.  Moreover, trivial updates are also
   324 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   325 occasionally, since simplification is more powerful by default.
   326 
   327 * Simplifier: automatically reasons about transitivity chains
   328 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   329 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   330 old proofs break occasionally as simplification may now solve more
   331 goals than previously.
   332 
   333 * Simplifier: converts x <= y into x = y if assumption y <= x is
   334 present.  Works for all partial orders (class "order"), in particular
   335 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   336 just like y <= x.
   337 
   338 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   339 bound variable or a constant then the let is unfolded.  Otherwise
   340 first a is simplified to b, and then f b is simplified to g. If
   341 possible we abstract b from g arriving at "let x = b in h x",
   342 otherwise we unfold the let and arrive at g.  The simproc can be
   343 enabled/disabled by the reference use_let_simproc.  Potential
   344 INCOMPATIBILITY since simplification is more powerful by default.
   345 
   346 * Classical reasoning: the meson method now accepts theorems as arguments.
   347 
   348 
   349 *** HOLCF ***
   350 
   351 * HOLCF: discontinued special version of 'constdefs' (which used to
   352 support continuous functions) in favor of the general Pure one with
   353 full type-inference.
   354 
   355 
   356 *** ZF ***
   357 
   358 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   359 including the First Isomorphism Theorem (on quotienting by the kernel
   360 of a homomorphism).
   361 
   362 * ZF/Simplifier: install second copy of type solver that actually
   363 makes use of TC rules declared to Isar proof contexts (or locales);
   364 the old version is still required for ML proof scripts.
   365 
   366 
   367 *** ML ***
   368 
   369 * Pure/library.ML no longer defines its own option datatype, but uses
   370 that of the SML basis, which has constructors NONE and SOME instead of
   371 None and Some, as well as exception Option.Option instead of OPTION.
   372 The functions the, if_none, is_some, is_none have been adapted
   373 accordingly, while Option.map replaces apsome.
   374 
   375 * The exception LIST has been given up in favour of the standard
   376 exceptions Empty and Subscript, as well as Library.UnequalLengths.
   377 Function like Library.hd and Library.tl are superceded by the standard
   378 hd and tl functions etc.
   379 
   380 A number of basic functions are now no longer exported to the ML
   381 toplevel, as they are variants of standard functions.  The following
   382 suggests how one can translate existing code:
   383 
   384     rev_append xs ys = List.revAppend (xs, ys)
   385     nth_elem (i, xs) = List.nth (xs, i)
   386     last_elem xs = List.last xs
   387     flat xss = List.concat xss
   388     seq fs = List.app fs
   389     partition P xs = List.partition P xs
   390     filter P xs = List.filter P xs
   391     mapfilter f xs = List.mapPartial f xs
   392 
   393 * Pure: output via the Isabelle channels of writeln/warning/error
   394 etc. is now passed through Output.output, with a hook for arbitrary
   395 transformations depending on the print_mode (cf. Output.add_mode --
   396 the first active mode that provides a output function wins).  Already
   397 formatted output may be embedded into further text via Output.raw; the
   398 result of Pretty.string_of/str_of and derived functions
   399 (string_of_term/cterm/thm etc.) is already marked raw to accommodate
   400 easy composition of diagnostic messages etc.  Programmers rarely need
   401 to care about Output.output or Output.raw at all, with some notable
   402 exceptions: Output.output is required when bypassing the standard
   403 channels (writeln etc.), or in token translations to produce properly
   404 formatted results; Output.raw is required when capturing already
   405 output material that will eventually be presented to the user a second
   406 time.  For the default print mode, both Output.output and Output.raw
   407 have no effect.
   408 
   409 * Pure: print_tac now outputs the goal through the trace channel.
   410 
   411 * Isar debugging: new reference Toplevel.debug (default false).  Set
   412 to make printing of exceptions THM, TERM, TYPE and THEORY more
   413 verbose.
   414 
   415 * Isar profiling: new reference Toplevel.profiling (default 0).  For
   416 Poly/ML, set to 1 to profile time, 2 to profile space (which increases
   417 the runtime).
   418 
   419 * Pure: structure OrdList (cf. Pure/General/ord_list.ML) provides a
   420 reasonably efficient light-weight implementation of sets as lists.
   421 
   422 * Pure: more efficient orders for basic syntactic entities: added
   423 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
   424 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
   425 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
   426 orders now -- potential INCOMPATIBILITY for code that depends on a
   427 particular order for Symtab.keys, Symtab.dest, etc. (consider using
   428 Library.sort_strings on result).
   429 
   430 * Pure: name spaces have been refined, with significant changes of the
   431 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   432 to extern(_table).  The plain name entry path is superceded by a
   433 general 'naming' context, which also includes the 'policy' to produce
   434 a fully qualified name and external accesses of a fully qualified
   435 name; NameSpace.extend is superceded by context dependent
   436 Sign.declare_name.  Several theory and proof context operations modify
   437 the naming context.  Especially note Theory.restore_naming and
   438 ProofContext.restore_naming to get back to a sane state; note that
   439 Theory.add_path is no longer sufficient to recover from
   440 Theory.absolute_path in particular.
   441 
   442 * Pure: new flags short_names (default false) and unique_names
   443 (default true) for controlling output of qualified names.  If
   444 short_names is set, names are printed unqualified.  If unique_names is
   445 reset, the name prefix is reduced to the minimum required to achieve
   446 the original result when interning again, even if there is an overlap
   447 with earlier declarations.
   448 
   449 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
   450 now 'extend', and 'merge' gets an additional Pretty.pp argument
   451 (useful for printing error messages).  INCOMPATIBILITY.
   452 
   453 * Pure: major reorganization of the theory context.  Type Sign.sg and
   454 Theory.theory are now identified, referring to the universal
   455 Context.theory (see Pure/context.ML).  Actual signature and theory
   456 content is managed as theory data.  The old code and interfaces were
   457 spread over many files and structures; the new arrangement introduces
   458 considerable INCOMPATIBILITY to gain more clarity:
   459 
   460   Context -- theory management operations (name, identity, inclusion,
   461     parents, ancestors, merge, etc.), plus generic theory data;
   462 
   463   Sign -- logical signature and syntax operations (declaring consts,
   464     types, etc.), plus certify/read for common entities;
   465 
   466   Theory -- logical theory operations (stating axioms, definitions,
   467     oracles), plus a copy of logical signature operations (consts,
   468     types, etc.); also a few basic management operations (Theory.copy,
   469     Theory.merge, etc.)
   470 
   471 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
   472 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
   473 for convenience -- they merely return the theory.
   474 
   475 * Pure: the Isar proof context type is already defined early in Pure
   476 as Context.proof (note that ProofContext.context and Proof.context are
   477 aliases, where the latter is the preferred name).  This enables other
   478 Isabelle components to refer to that type even before Isar is present.
   479 
   480 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   481 typeK, constK, axiomK, oracleK), but provide explicit operations for
   482 any of these kinds.  For example, Sign.intern typeK is now
   483 Sign.intern_type, Theory.hide_space Sign.typeK is now
   484 Theory.hide_types.  Also note that former
   485 Theory.hide_classes/types/consts are now
   486 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   487 internalize their arguments!  INCOMPATIBILITY.
   488 
   489 * Pure: get_thm interface (of PureThy and ProofContext) expects
   490 datatype thmref (with constructors Name and NameSelection) instead of
   491 plain string -- INCOMPATIBILITY;
   492 
   493 * Pure: cases produced by proof methods specify options, where NONE
   494 means to remove case bindings -- INCOMPATIBILITY in
   495 (RAW_)METHOD_CASES.
   496 
   497 * Pure: the following operations retrieve axioms or theorems from a
   498 theory node or theory hierarchy, respectively:
   499 
   500   Theory.axioms_of: theory -> (string * term) list
   501   Theory.all_axioms_of: theory -> (string * term) list
   502   PureThy.thms_of: theory -> (string * thm) list
   503   PureThy.all_thms_of: theory -> (string * thm) list
   504 
   505 * Provers: Simplifier and Classical Reasoner now support proof context
   506 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   507 components are stored in the theory and patched into the
   508 simpset/claset when used in an Isar proof context.  Context dependent
   509 components are maintained by the following theory operations:
   510 
   511   Simplifier.add_context_simprocs
   512   Simplifier.del_context_simprocs
   513   Simplifier.set_context_subgoaler
   514   Simplifier.reset_context_subgoaler
   515   Simplifier.add_context_looper
   516   Simplifier.del_context_looper
   517   Simplifier.add_context_unsafe_solver
   518   Simplifier.add_context_safe_solver
   519 
   520   Classical.add_context_safe_wrapper
   521   Classical.del_context_safe_wrapper
   522   Classical.add_context_unsafe_wrapper
   523   Classical.del_context_unsafe_wrapper
   524 
   525 IMPORTANT NOTE: proof tools (methods etc.) need to use
   526 local_simpset_of and local_claset_of to instead of the primitive
   527 Simplifier.get_local_simpset and Classical.get_local_claset,
   528 respectively, in order to see the context dependent fields!
   529 
   530 * File.sysify_path and File.quote_sysify path have been replaced by
   531 File.platform_path and File.shell_path (with appropriate hooks).  This
   532 provides a clean interface for unusual systems where the internal and
   533 external process view of file names are different.
   534 
   535 
   536 *** System ***
   537 
   538 * Allow symlinks to all proper Isabelle executables (Isabelle,
   539 isabelle, isatool etc.).
   540 
   541 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   542 isatool doc, isatool mkdir, display_drafts etc.).
   543 
   544 * isatool usedir: option -f allows specification of the ML file to be
   545 used by Isabelle; default is ROOT.ML.
   546 
   547 * New isatool version outputs the version identifier of the Isabelle
   548 distribution being used.
   549 
   550 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
   551 (containing Boolean satisfiability problems) into Isabelle/HOL
   552 theories.
   553 
   554 
   555 
   556 New in Isabelle2004 (April 2004)
   557 --------------------------------
   558 
   559 *** General ***
   560 
   561 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   562   Replaces linorder.ML.
   563 
   564 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   565   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   566   (\<a>...\<z>), are now considered normal letters, and can therefore
   567   be used anywhere where an ASCII letter (a...zA...Z) has until
   568   now. COMPATIBILITY: This obviously changes the parsing of some
   569   terms, especially where a symbol has been used as a binder, say
   570   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   571   as an identifier.  Fix it by inserting a space around former
   572   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   573   existing theory and ML files.
   574 
   575 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   576 
   577 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   578   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   579   a normal (but invisible) letter. For multiple letter subscripts repeat
   580   \<^isub> like this: x\<^isub>1\<^isub>2.
   581 
   582 * Pure: There are now sub-/superscripts that can span more than one
   583   character. Text between \<^bsub> and \<^esub> is set in subscript in
   584   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   585   superscript. The new control characters are not identifier parts.
   586 
   587 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   588   content of "..." to the latex file instead of \isacntrl... . The "..."
   589   may consist of any printable characters excluding the end bracket >.
   590 
   591 * Pure: Using new Isar command "finalconsts" (or the ML functions
   592   Theory.add_finals or Theory.add_finals_i) it is now possible to
   593   declare constants "final", which prevents their being given a definition
   594   later.  It is useful for constants whose behaviour is fixed axiomatically
   595   rather than definitionally, such as the meta-logic connectives.
   596 
   597 * Pure: 'instance' now handles general arities with general sorts
   598   (i.e. intersections of classes),
   599 
   600 * Presentation: generated HTML now uses a CSS style sheet to make layout
   601   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   602   It can be changed to alter the colors/layout of generated pages.
   603 
   604 
   605 *** Isar ***
   606 
   607 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   608   cut_tac, subgoal_tac and thin_tac:
   609   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   610     locales are no longer forced to write Isar proof scripts.
   611     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   612     emulations.
   613   - INCOMPATIBILITY: names of variables to be instantiated may no
   614     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   615     This is consistent with the instantiation attribute "where".
   616 
   617 * Attributes "where" and "of":
   618   - Now take type variables of instantiated theorem into account when reading
   619     the instantiation string.  This fixes a bug that caused instantiated
   620     theorems to have too special types in some circumstances.
   621   - "where" permits explicit instantiations of type variables.
   622 
   623 * Calculation commands "moreover" and "also" no longer interfere with
   624   current facts ("this"), admitting arbitrary combinations with "then"
   625   and derived forms.
   626 
   627 * Locales:
   628   - Goal statements involving the context element "includes" no longer
   629     generate theorems with internal delta predicates (those ending on
   630     "_axioms") in the premise.
   631     Resolve particular premise with <locale>.intro to obtain old form.
   632   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   633     specification and "includes" elements in goal statement.
   634   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   635     [intro?] and [elim?] (respectively) by default.
   636   - Experimental command for instantiation of locales in proof contexts:
   637         instantiate <label>[<attrs>]: <loc>
   638     Instantiates locale <loc> and adds all its theorems to the current context
   639     taking into account their attributes.  Label and attrs are optional
   640     modifiers, like in theorem declarations.  If present, names of
   641     instantiated theorems are qualified with <label>, and the attributes
   642     <attrs> are applied after any attributes these theorems might have already.
   643       If the locale has assumptions, a chained fact of the form
   644     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   645     are derived.  The command does not support old-style locales declared
   646     with "locale (open)".
   647       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   648 
   649 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   650   (Isar) contexts.
   651 
   652 
   653 *** HOL ***
   654 
   655 * Proof import: new image HOL4 contains the imported library from
   656   the HOL4 system with about 2500 theorems. It is imported by
   657   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   658   can be used like any other Isabelle image.  See
   659   HOL/Import/HOL/README for more information.
   660 
   661 * Simplifier:
   662   - Much improved handling of linear and partial orders.
   663     Reasoners for linear and partial orders are set up for type classes
   664     "linorder" and "order" respectively, and are added to the default simpset
   665     as solvers.  This means that the simplifier can build transitivity chains
   666     to solve goals from the assumptions.
   667   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   668     of blast or auto after simplification become unnecessary because the goal
   669     is solved by simplification already.
   670 
   671 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   672     all proved in axiomatic type classes for semirings, rings and fields.
   673 
   674 * Numerics:
   675   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   676     now formalized using the Ring_and_Field theory mentioned above.
   677   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   678     than before, because now they are set up once in a generic manner.
   679   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   680     Look for the general versions in Ring_and_Field (and Power if they concern
   681     exponentiation).
   682 
   683 * Type "rat" of the rational numbers is now available in HOL-Complex.
   684 
   685 * Records:
   686   - Record types are now by default printed with their type abbreviation
   687     instead of the list of all field types. This can be configured via
   688     the reference "print_record_type_abbr".
   689   - Simproc "record_upd_simproc" for simplification of multiple updates added
   690     (not enabled by default).
   691   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   692     EX x. x = sel r to True (not enabled by default).
   693   - Tactic "record_split_simp_tac" to split and simplify records added.
   694 
   695 * 'specification' command added, allowing for definition by
   696   specification.  There is also an 'ax_specification' command that
   697   introduces the new constants axiomatically.
   698 
   699 * arith(_tac) is now able to generate counterexamples for reals as well.
   700 
   701 * HOL-Algebra: new locale "ring" for non-commutative rings.
   702 
   703 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   704   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   705 
   706 * HOL-Matrix: a first theory for matrices in HOL with an application of
   707   matrix theory to linear programming.
   708 
   709 * Unions and Intersections:
   710   The latex output syntax of UN and INT has been changed
   711   from "\Union x \in A. B" to "\Union_{x \in A} B"
   712   i.e. the index formulae has become a subscript.
   713   Similarly for "\Union x. B", and for \Inter instead of \Union.
   714 
   715 * Unions and Intersections over Intervals:
   716   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   717   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   718   like in normal math, and corresponding versions for < and for intersection.
   719 
   720 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   721   lexicographic dictonary ordering has been added as "lexord".
   722 
   723 * ML: the legacy theory structures Int and List have been removed. They had
   724   conflicted with ML Basis Library structures having the same names.
   725 
   726 * 'refute' command added to search for (finite) countermodels.  Only works
   727   for a fragment of HOL.  The installation of an external SAT solver is
   728   highly recommended.  See "HOL/Refute.thy" for details.
   729 
   730 * 'quickcheck' command: Allows to find counterexamples by evaluating
   731   formulae under an assignment of free variables to random values.
   732   In contrast to 'refute', it can deal with inductive datatypes,
   733   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   734   for examples.
   735 
   736 
   737 *** HOLCF ***
   738 
   739 * Streams now come with concatenation and are part of the HOLCF image
   740 
   741 
   742 
   743 New in Isabelle2003 (May 2003)
   744 ------------------------------
   745 
   746 *** General ***
   747 
   748 * Provers/simplifier:
   749 
   750   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   751     Assumptions are now subject to complete mutual simplification,
   752     not just from left to right. The simplifier now preserves
   753     the order of assumptions.
   754 
   755     Potential INCOMPATIBILITY:
   756 
   757     -- simp sometimes diverges where the old version did
   758        not, e.g. invoking simp on the goal
   759 
   760         [| P (f x); y = x; f x = f y |] ==> Q
   761 
   762        now gives rise to the infinite reduction sequence
   763 
   764         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   765 
   766        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   767        kind of problem.
   768 
   769     -- Tactics combining classical reasoner and simplification (such as auto)
   770        are also affected by this change, because many of them rely on
   771        simp. They may sometimes diverge as well or yield a different numbers
   772        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   773        in case of problems. Sometimes subsequent calls to the classical
   774        reasoner will fail because a preceeding call to the simplifier too
   775        eagerly simplified the goal, e.g. deleted redundant premises.
   776 
   777   - The simplifier trace now shows the names of the applied rewrite rules
   778 
   779   - You can limit the number of recursive invocations of the simplifier
   780     during conditional rewriting (where the simplifie tries to solve the
   781     conditions before applying the rewrite rule):
   782     ML "simp_depth_limit := n"
   783     where n is an integer. Thus you can force termination where previously
   784     the simplifier would diverge.
   785 
   786   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   787 
   788   - No longer aborts on failed congruence proof.  Instead, the
   789     congruence is ignored.
   790 
   791 * Pure: New generic framework for extracting programs from constructive
   792   proofs. See HOL/Extraction.thy for an example instantiation, as well
   793   as HOL/Extraction for some case studies.
   794 
   795 * Pure: The main goal of the proof state is no longer shown by default, only
   796 the subgoals. This behaviour is controlled by a new flag.
   797    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   798 (ML: Proof.show_main_goal).
   799 
   800 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   801 rules whose conclusion matches subgoal 1:
   802       PG menu: Isabelle/Isar -> Show me -> matching rules
   803 The rules are ordered by how closely they match the subgoal.
   804 In particular, rules that solve a subgoal outright are displayed first
   805 (or rather last, the way they are printed).
   806 (ML: ProofGeneral.print_intros())
   807 
   808 * Pure: New flag trace_unify_fail causes unification to print
   809 diagnostic information (PG: in trace buffer) when it fails. This is
   810 useful for figuring out why single step proofs like rule, erule or
   811 assumption failed.
   812 
   813 * Pure: Locale specifications now produce predicate definitions
   814 according to the body of text (covering assumptions modulo local
   815 definitions); predicate "loc_axioms" covers newly introduced text,
   816 while "loc" is cumulative wrt. all included locale expressions; the
   817 latter view is presented only on export into the global theory
   818 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   819 on the old view without predicates;
   820 
   821 * Pure: predefined locales "var" and "struct" are useful for sharing
   822 parameters (as in CASL, for example); just specify something like
   823 ``var x + var y + struct M'' as import;
   824 
   825 * Pure: improved thms_containing: proper indexing of facts instead of
   826 raw theorems; check validity of results wrt. current name space;
   827 include local facts of proof configuration (also covers active
   828 locales), cover fixed variables in index; may use "_" in term
   829 specification; an optional limit for the number of printed facts may
   830 be given (the default is 40);
   831 
   832 * Pure: disallow duplicate fact bindings within new-style theory files
   833 (batch-mode only);
   834 
   835 * Provers: improved induct method: assumptions introduced by case
   836 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   837 the goal statement); "foo" still refers to all facts collectively;
   838 
   839 * Provers: the function blast.overloaded has been removed: all constants
   840 are regarded as potentially overloaded, which improves robustness in exchange
   841 for slight decrease in efficiency;
   842 
   843 * Provers/linorder: New generic prover for transitivity reasoning over
   844 linear orders.  Note: this prover is not efficient!
   845 
   846 * Isar: preview of problems to finish 'show' now produce an error
   847 rather than just a warning (in interactive mode);
   848 
   849 
   850 *** HOL ***
   851 
   852 * arith(_tac)
   853 
   854  - Produces a counter example if it cannot prove a goal.
   855    Note that the counter example may be spurious if the goal is not a formula
   856    of quantifier-free linear arithmetic.
   857    In ProofGeneral the counter example appears in the trace buffer.
   858 
   859  - Knows about div k and mod k where k is a numeral of type nat or int.
   860 
   861  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   862    linear arithmetic fails. This takes account of quantifiers and divisibility.
   863    Presburger arithmetic can also be called explicitly via presburger(_tac).
   864 
   865 * simp's arithmetic capabilities have been enhanced a bit: it now
   866 takes ~= in premises into account (by performing a case split);
   867 
   868 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   869 are distributed over a sum of terms;
   870 
   871 * New tactic "trans_tac" and method "trans" instantiate
   872 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   873 "<=", "<" and "=").
   874 
   875 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   876 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   877 
   878 * 'typedef' command has new option "open" to suppress the set
   879 definition;
   880 
   881 * functions Min and Max on finite sets have been introduced (theory
   882 Finite_Set);
   883 
   884 * attribute [symmetric] now works for relations as well; it turns
   885 (x,y) : R^-1 into (y,x) : R, and vice versa;
   886 
   887 * induct over a !!-quantified statement (say !!x1..xn):
   888   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   889 
   890 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   891 %x. None. Warning: empty_def now refers to the previously hidden definition
   892 of the empty set.
   893 
   894 * Algebra: formalization of classical algebra.  Intended as base for
   895 any algebraic development in Isabelle.  Currently covers group theory
   896 (up to Sylow's theorem) and ring theory (Universal Property of
   897 Univariate Polynomials).  Contributions welcome;
   898 
   899 * GroupTheory: deleted, since its material has been moved to Algebra;
   900 
   901 * Complex: new directory of the complex numbers with numeric constants,
   902 nonstandard complex numbers, and some complex analysis, standard and
   903 nonstandard (Jacques Fleuriot);
   904 
   905 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   906 
   907 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   908 Fleuriot);
   909 
   910 * Real/HahnBanach: updated and adapted to locales;
   911 
   912 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   913 Gray and Kramer);
   914 
   915 * UNITY: added the Meier-Sanders theory of progress sets;
   916 
   917 * MicroJava: bytecode verifier and lightweight bytecode verifier
   918 as abstract algorithms, instantiated to the JVM;
   919 
   920 * Bali: Java source language formalization. Type system, operational
   921 semantics, axiomatic semantics. Supported language features:
   922 classes, interfaces, objects,virtual methods, static methods,
   923 static/instance fields, arrays, access modifiers, definite
   924 assignment, exceptions.
   925 
   926 
   927 *** ZF ***
   928 
   929 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   930 universe, etc.);
   931 
   932 * Main ZF: virtually all theories converted to new-style format;
   933 
   934 
   935 *** ML ***
   936 
   937 * Pure: Tactic.prove provides sane interface for internal proofs;
   938 omits the infamous "standard" operation, so this is more appropriate
   939 than prove_goalw_cterm in many situations (e.g. in simprocs);
   940 
   941 * Pure: improved error reporting of simprocs;
   942 
   943 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   944 up simprocs;
   945 
   946 
   947 *** Document preparation ***
   948 
   949 * uses \par instead of \\ for line breaks in theory text. This may
   950 shift some page breaks in large documents. To get the old behaviour
   951 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   952 
   953 * minimized dependencies of isabelle.sty and isabellesym.sty on
   954 other packages
   955 
   956 * \<euro> now needs package babel/greek instead of marvosym (which
   957 broke \Rightarrow)
   958 
   959 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   960 textcomp package)
   961 
   962 
   963 
   964 New in Isabelle2002 (March 2002)
   965 --------------------------------
   966 
   967 *** Document preparation ***
   968 
   969 * greatly simplified document preparation setup, including more
   970 graceful interpretation of isatool usedir -i/-d/-D options, and more
   971 instructive isatool mkdir; users should basically be able to get
   972 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   973 users may run a separate document processing stage manually like this:
   974 "isatool usedir -D output HOL Test && isatool document Test/output";
   975 
   976 * theory dependency graph may now be incorporated into documents;
   977 isatool usedir -g true will produce session_graph.eps/.pdf for use
   978 with \includegraphics of LaTeX;
   979 
   980 * proper spacing of consecutive markup elements, especially text
   981 blocks after section headings;
   982 
   983 * support bold style (for single symbols only), input syntax is like
   984 this: "\<^bold>\<alpha>" or "\<^bold>A";
   985 
   986 * \<bullet> is now output as bold \cdot by default, which looks much
   987 better in printed text;
   988 
   989 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   990 note that these symbols are currently unavailable in Proof General /
   991 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   992 
   993 * isatool latex no longer depends on changed TEXINPUTS, instead
   994 isatool document copies the Isabelle style files to the target
   995 location;
   996 
   997 
   998 *** Isar ***
   999 
  1000 * Pure/Provers: improved proof by cases and induction;
  1001   - 'case' command admits impromptu naming of parameters (such as
  1002     "case (Suc n)");
  1003   - 'induct' method divinates rule instantiation from the inductive
  1004     claim; no longer requires excessive ?P bindings for proper
  1005     instantiation of cases;
  1006   - 'induct' method properly enumerates all possibilities of set/type
  1007     rules; as a consequence facts may be also passed through *type*
  1008     rules without further ado;
  1009   - 'induct' method now derives symbolic cases from the *rulified*
  1010     rule (before it used to rulify cases stemming from the internal
  1011     atomized version); this means that the context of a non-atomic
  1012     statement becomes is included in the hypothesis, avoiding the
  1013     slightly cumbersome show "PROP ?case" form;
  1014   - 'induct' may now use elim-style induction rules without chaining
  1015     facts, using ``missing'' premises from the goal state; this allows
  1016     rules stemming from inductive sets to be applied in unstructured
  1017     scripts, while still benefitting from proper handling of non-atomic
  1018     statements; NB: major inductive premises need to be put first, all
  1019     the rest of the goal is passed through the induction;
  1020   - 'induct' proper support for mutual induction involving non-atomic
  1021     rule statements (uses the new concept of simultaneous goals, see
  1022     below);
  1023   - append all possible rule selections, but only use the first
  1024     success (no backtracking);
  1025   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1026   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1027   - added 'print_induct_rules' (covered by help item in recent Proof
  1028     General versions);
  1029   - moved induct/cases attributes to Pure, methods to Provers;
  1030   - generic method setup instantiated for FOL and HOL;
  1031 
  1032 * Pure: support multiple simultaneous goal statements, for example
  1033 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1034 meta-level mechanism, this acts as if several individual goals had
  1035 been stated separately; in particular common proof methods need to be
  1036 repeated in order to cover all claims; note that a single elimination
  1037 step is *not* sufficient to establish the two conjunctions, so this
  1038 fails:
  1039 
  1040   assume "A & B" then have A and B ..   (*".." fails*)
  1041 
  1042 better use "obtain" in situations as above; alternative refer to
  1043 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1044 
  1045 * Pure: proper integration with ``locales''; unlike the original
  1046 version by Florian Kammller, Isar locales package high-level proof
  1047 contexts rather than raw logical ones (e.g. we admit to include
  1048 attributes everywhere); operations on locales include merge and
  1049 rename; support for implicit arguments (``structures''); simultaneous
  1050 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1051 some examples;
  1052 
  1053 * Pure: the following commands have been ``localized'', supporting a
  1054 target locale specification "(in name)": 'lemma', 'theorem',
  1055 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1056 stored both within the locale and at the theory level (exported and
  1057 qualified by the locale name);
  1058 
  1059 * Pure: theory goals may now be specified in ``long'' form, with
  1060 ad-hoc contexts consisting of arbitrary locale elements. for example
  1061 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1062 definitions may be given, too); the result is a meta-level rule with
  1063 the context elements being discharged in the obvious way;
  1064 
  1065 * Pure: new proof command 'using' allows to augment currently used
  1066 facts after a goal statement ('using' is syntactically analogous to
  1067 'apply', but acts on the goal's facts only); this allows chained facts
  1068 to be separated into parts given before and after a claim, as in
  1069 ``from a and b have C using d and e <proof>'';
  1070 
  1071 * Pure: renamed "antecedent" case to "rule_context";
  1072 
  1073 * Pure: new 'judgment' command records explicit information about the
  1074 object-logic embedding (used by several tools internally); no longer
  1075 use hard-wired "Trueprop";
  1076 
  1077 * Pure: added 'corollary' command;
  1078 
  1079 * Pure: fixed 'token_translation' command;
  1080 
  1081 * Pure: removed obsolete 'exported' attribute;
  1082 
  1083 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1084 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1085 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1086 
  1087 * Pure: method 'atomize' presents local goal premises as object-level
  1088 statements (atomic meta-level propositions); setup controlled via
  1089 rewrite rules declarations of 'atomize' attribute; example
  1090 application: 'induct' method with proper rule statements in improper
  1091 proof *scripts*;
  1092 
  1093 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1094 now consider the syntactic context of assumptions, giving a better
  1095 chance to get type-inference of the arguments right (this is
  1096 especially important for locales);
  1097 
  1098 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1099 mode;
  1100 
  1101 * Pure/obtain: the formal conclusion "thesis", being marked as
  1102 ``internal'', may no longer be reference directly in the text;
  1103 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1104 situations;
  1105 
  1106 * Pure: generic 'sym' attribute which declares a rule both as pure
  1107 'elim?' and for the 'symmetric' operation;
  1108 
  1109 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1110 text; the fixed correlation with particular command syntax has been
  1111 discontinued;
  1112 
  1113 * Pure: new method 'rules' is particularly well-suited for proof
  1114 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1115 but often produces more compact proof terms with less detours;
  1116 
  1117 * Pure/Provers/classical: simplified integration with pure rule
  1118 attributes and methods; the classical "intro?/elim?/dest?"
  1119 declarations coincide with the pure ones; the "rule" method no longer
  1120 includes classically swapped intros; "intro" and "elim" methods no
  1121 longer pick rules from the context; also got rid of ML declarations
  1122 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1123 INCOMPATIBILITY;
  1124 
  1125 * Provers/classical: attribute 'swapped' produces classical inversions
  1126 of introduction rules;
  1127 
  1128 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1129 rules instead of full simplifier context; 'iff' attribute handles
  1130 conditional rules;
  1131 
  1132 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1133 
  1134 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1135 "(permissive)" option to recover old behavior;
  1136 
  1137 * HOL: 'inductive' no longer features separate (collective) attributes
  1138 for 'intros' (was found too confusing);
  1139 
  1140 * HOL: properly declared induction rules less_induct and
  1141 wf_induct_rule;
  1142 
  1143 
  1144 *** HOL ***
  1145 
  1146 * HOL: moved over to sane numeral syntax; the new policy is as
  1147 follows:
  1148 
  1149   - 0 and 1 are polymorphic constants, which are defined on any
  1150   numeric type (nat, int, real etc.);
  1151 
  1152   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1153   binary representation internally;
  1154 
  1155   - type nat has special constructor Suc, and generally prefers Suc 0
  1156   over 1::nat and Suc (Suc 0) over 2::nat;
  1157 
  1158 This change may cause significant problems of INCOMPATIBILITY; here
  1159 are some hints on converting existing sources:
  1160 
  1161   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1162   entities, so expressions involving "-" (unary or binary minus) need
  1163   to be spaced properly;
  1164 
  1165   - existing occurrences of "1" may need to be constraint "1::nat" or
  1166   even replaced by Suc 0; similar for old "2";
  1167 
  1168   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1169 
  1170   - remove all special provisions on numerals in proofs;
  1171 
  1172 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1173 representation (depends on bin_arith_simps in the default context);
  1174 
  1175 * HOL: symbolic syntax for x^2 (numeral 2);
  1176 
  1177 * HOL: the class of all HOL types is now called "type" rather than
  1178 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1179 in axclass/classes, instance/arities, and (usually rare) occurrences
  1180 in typings (of consts etc.); internally the class is called
  1181 "HOL.type", ML programs should refer to HOLogic.typeS;
  1182 
  1183 * HOL/record package improvements:
  1184   - new derived operations "fields" to build a partial record section,
  1185     "extend" to promote a fixed record to a record scheme, and
  1186     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1187     declared as simp by default;
  1188   - shared operations ("more", "fields", etc.) now need to be always
  1189     qualified) --- potential INCOMPATIBILITY;
  1190   - removed "make_scheme" operations (use "make" with "extend") --
  1191     INCOMPATIBILITY;
  1192   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1193   - provides cases/induct rules for use with corresponding Isar
  1194     methods (for concrete records, record schemes, concrete more
  1195     parts, and schematic more parts -- in that order);
  1196   - internal definitions directly based on a light-weight abstract
  1197     theory of product types over typedef rather than datatype;
  1198 
  1199 * HOL: generic code generator for generating executable ML code from
  1200 specifications; specific support for HOL constructs such as inductive
  1201 datatypes and sets, as well as recursive functions; can be invoked
  1202 via 'generate_code' theory section;
  1203 
  1204 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1205 
  1206 * HOL: consolidated and renamed several theories.  In particular:
  1207         Ord.thy has been absorbed into HOL.thy
  1208         String.thy has been absorbed into List.thy
  1209 
  1210 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1211 (beware of argument permutation!);
  1212 
  1213 * HOL: linorder_less_split superseded by linorder_cases;
  1214 
  1215 * HOL/List: "nodups" renamed to "distinct";
  1216 
  1217 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1218 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1219   - Ex_def has changed, now need to use some_eq_ex
  1220 
  1221 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1222 in this (rare) case use:
  1223 
  1224   delSWrapper "split_all_tac"
  1225   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1226 
  1227 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1228 MAY FAIL;
  1229 
  1230 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1231 Isabelle's type classes, ^ on functions and relations has too general
  1232 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1233 necessary to attach explicit type constraints;
  1234 
  1235 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1236 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1237 renamed accordingly (eg "compI" -> "rel_compI").
  1238 
  1239 * HOL: syntax translations now work properly with numerals and records
  1240 expressions;
  1241 
  1242 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1243 of "lam" -- INCOMPATIBILITY;
  1244 
  1245 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1246 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1247 renamed "Product_Type.unit";
  1248 
  1249 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1250 
  1251 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1252 the "cases" method);
  1253 
  1254 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1255 Florian Kammller);
  1256 
  1257 * HOL/IMP: updated and converted to new-style theory format; several
  1258 parts turned into readable document, with proper Isar proof texts and
  1259 some explanations (by Gerwin Klein);
  1260 
  1261 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1262 
  1263 * HOL-Hyperreal is now a logic image;
  1264 
  1265 
  1266 *** HOLCF ***
  1267 
  1268 * Isar: consts/constdefs supports mixfix syntax for continuous
  1269 operations;
  1270 
  1271 * Isar: domain package adapted to new-style theory format, e.g. see
  1272 HOLCF/ex/Dnat.thy;
  1273 
  1274 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1275 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1276 lift.induct_tac, always use UU instead of Undef;
  1277 
  1278 * HOLCF/IMP: updated and converted to new-style theory;
  1279 
  1280 
  1281 *** ZF ***
  1282 
  1283 * Isar: proper integration of logic-specific tools and packages,
  1284 including theory commands '(co)inductive', '(co)datatype',
  1285 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1286 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1287 
  1288 * theory Main no longer includes AC; for the Axiom of Choice, base
  1289 your theory on Main_ZFC;
  1290 
  1291 * the integer library now covers quotients and remainders, with many
  1292 laws relating division to addition, multiplication, etc.;
  1293 
  1294 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1295 typeless version of the formalism;
  1296 
  1297 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1298 format;
  1299 
  1300 * ZF/Induct: new directory for examples of inductive definitions,
  1301 including theory Multiset for multiset orderings; converted to
  1302 new-style theory format;
  1303 
  1304 * ZF: many new theorems about lists, ordinals, etc.;
  1305 
  1306 
  1307 *** General ***
  1308 
  1309 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1310 variable proof controls level of detail: 0 = no proofs (only oracle
  1311 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1312 also ref manual for further ML interfaces;
  1313 
  1314 * Pure/axclass: removed obsolete ML interface
  1315 goal_subclass/goal_arity;
  1316 
  1317 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1318 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1319 separate tokens, so expressions involving minus need to be spaced
  1320 properly;
  1321 
  1322 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1323 rather than "infixl" or "infixr";
  1324 
  1325 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1326 sort constraint specifications in type inference; e.g. "x::_::foo"
  1327 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1328 type variable);
  1329 
  1330 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1331 control output of nested => (types); the default behavior is
  1332 "type_brackets";
  1333 
  1334 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1335 tokens into AST constants;
  1336 
  1337 * Pure/syntax: prefer later declarations of translations and print
  1338 translation functions; potential INCOMPATIBILITY: need to reverse
  1339 multiple declarations for same syntax element constant;
  1340 
  1341 * Pure/show_hyps reset by default (in accordance to existing Isar
  1342 practice);
  1343 
  1344 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1345 addSafter;
  1346 
  1347 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1348 as well;
  1349 
  1350 * system: tested support for MacOS X; should be able to get Isabelle +
  1351 Proof General to work in a plain Terminal after installing Poly/ML
  1352 (e.g. from the Isabelle distribution area) and GNU bash alone
  1353 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1354 support requires further installations, e.g. from
  1355 http://fink.sourceforge.net/);
  1356 
  1357 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1358 
  1359 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1360 of 40 MB), cf. ML_OPTIONS;
  1361 
  1362 * system: Proof General keywords specification is now part of the
  1363 Isabelle distribution (see etc/isar-keywords.el);
  1364 
  1365 * system: support for persistent Proof General sessions (refrain from
  1366 outdating all loaded theories on startup); user may create writable
  1367 logic images like this: ``isabelle -q HOL Test'';
  1368 
  1369 * system: smart selection of Isabelle process versus Isabelle
  1370 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1371 run both "isabelle" and "Isabelle" even if file names are badly
  1372 damaged (executable inspects the case of the first letter of its own
  1373 name); added separate "isabelle-process" and "isabelle-interface";
  1374 
  1375 * system: refrain from any attempt at filtering input streams; no
  1376 longer support ``8bit'' encoding of old isabelle font, instead proper
  1377 iso-latin characters may now be used; the related isatools
  1378 "symbolinput" and "nonascii" have disappeared as well;
  1379 
  1380 * system: removed old "xterm" interface (the print modes "xterm" and
  1381 "xterm_color" are still available for direct use in a suitable
  1382 terminal);
  1383 
  1384 
  1385 
  1386 New in Isabelle99-2 (February 2001)
  1387 -----------------------------------
  1388 
  1389 *** Overview of INCOMPATIBILITIES ***
  1390 
  1391 * HOL: please note that theories in the Library and elsewhere often use the
  1392 new-style (Isar) format; to refer to their theorems in an ML script you must
  1393 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1394 
  1395 * HOL: inductive package no longer splits induction rule aggressively,
  1396 but only as far as specified by the introductions given; the old
  1397 format may be recovered via ML function complete_split_rule or attribute
  1398 'split_rule (complete)';
  1399 
  1400 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1401 gfp_Tarski to gfp_unfold;
  1402 
  1403 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1404 
  1405 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1406 relation); infix "^^" has been renamed "``"; infix "``" has been
  1407 renamed "`"; "univalent" has been renamed "single_valued";
  1408 
  1409 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1410 operation;
  1411 
  1412 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1413 
  1414 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1415 
  1416 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1417 consequence, it is no longer monotonic wrt. the local goal context
  1418 (which is now passed through the inductive cases);
  1419 
  1420 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1421 \<gg> to \<ggreater>;
  1422 
  1423 
  1424 *** Document preparation ***
  1425 
  1426 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1427 available: are "it" for near math-mode best-style output, "sl" for
  1428 slanted text style, and "tt" for plain type-writer; if no
  1429 \isabellestyle command is given, output is according to slanted
  1430 type-writer);
  1431 
  1432 * support sub/super scripts (for single symbols only), input syntax is
  1433 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1434 
  1435 * some more standard symbols; see Appendix A of the system manual for
  1436 the complete list of symbols defined in isabellesym.sty;
  1437 
  1438 * improved isabelle style files; more abstract symbol implementation
  1439 (should now use \isamath{...} and \isatext{...} in custom symbol
  1440 definitions);
  1441 
  1442 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1443 state; Note that presentation of goal states does not conform to
  1444 actual human-readable proof documents.  Please do not include goal
  1445 states into document output unless you really know what you are doing!
  1446 
  1447 * proper indentation of antiquoted output with proportional LaTeX
  1448 fonts;
  1449 
  1450 * no_document ML operator temporarily disables LaTeX document
  1451 generation;
  1452 
  1453 * isatool unsymbolize tunes sources for plain ASCII communication;
  1454 
  1455 
  1456 *** Isar ***
  1457 
  1458 * Pure: Isar now suffers initial goal statements to contain unbound
  1459 schematic variables (this does not conform to actual readable proof
  1460 documents, due to unpredictable outcome and non-compositional proof
  1461 checking); users who know what they are doing may use schematic goals
  1462 for Prolog-style synthesis of proven results;
  1463 
  1464 * Pure: assumption method (an implicit finishing) now handles actual
  1465 rules as well;
  1466 
  1467 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1468 initial goal, declare "that" only as Pure intro (only for single
  1469 steps); the "that" rule assumption may now be involved in implicit
  1470 finishing, thus ".." becomes a feasible for trivial obtains;
  1471 
  1472 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1473 instance proofs may be performed by "..";
  1474 
  1475 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1476 statements as well;
  1477 
  1478 * Pure: more robust selection of calculational rules;
  1479 
  1480 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1481 rule (as well as the assumption rule);
  1482 
  1483 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1484 lemmas, using the graph browser tool;
  1485 
  1486 * Pure: predict failure of "show" in interactive mode;
  1487 
  1488 * Pure: 'thms_containing' now takes actual terms as arguments;
  1489 
  1490 * HOL: improved method 'induct' --- now handles non-atomic goals
  1491 (potential INCOMPATIBILITY); tuned error handling;
  1492 
  1493 * HOL: cases and induct rules now provide explicit hints about the
  1494 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1495 any remaining facts are inserted into the goal verbatim;
  1496 
  1497 * HOL: local contexts (aka cases) may now contain term bindings as
  1498 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1499 the result to be shown in each case;
  1500 
  1501 * HOL: added 'recdef_tc' command;
  1502 
  1503 * isatool convert assists in eliminating legacy ML scripts;
  1504 
  1505 
  1506 *** HOL ***
  1507 
  1508 * HOL/Library: a collection of generic theories to be used together
  1509 with main HOL; the theory loader path already includes this directory
  1510 by default; the following existing theories have been moved here:
  1511 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1512 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1513 
  1514 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1515 modelling and verification task performed in Isabelle/HOL +
  1516 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1517 
  1518 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1519 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1520 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1521 'domain', this makes the theory consistent with mathematical
  1522 literature;
  1523 
  1524 * HOL basics: added overloaded operations "inverse" and "divide"
  1525 (infix "/"), syntax for generic "abs" operation, generic summation
  1526 operator \<Sum>;
  1527 
  1528 * HOL/typedef: simplified package, provide more useful rules (see also
  1529 HOL/subset.thy);
  1530 
  1531 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1532 now expressed as a proper nested rule (old-style tactic scripts may
  1533 require atomize_strip_tac to cope with non-atomic premises);
  1534 
  1535 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1536 to "split_conv" (old name still available for compatibility);
  1537 
  1538 * HOL: improved concrete syntax for strings (e.g. allows translation
  1539 rules with string literals);
  1540 
  1541 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1542  and Fleuriot's mechanization of analysis, including the transcendental
  1543  functions for the reals;
  1544 
  1545 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1546 
  1547 
  1548 *** CTT ***
  1549 
  1550 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1551 "lam" is displayed as TWO lambda-symbols
  1552 
  1553 * CTT: theory Main now available, containing everything (that is, Bool
  1554 and Arith);
  1555 
  1556 
  1557 *** General ***
  1558 
  1559 * Pure: the Simplifier has been implemented properly as a derived rule
  1560 outside of the actual kernel (at last!); the overall performance
  1561 penalty in practical applications is about 50%, while reliability of
  1562 the Isabelle inference kernel has been greatly improved;
  1563 
  1564 * print modes "brackets" and "no_brackets" control output of nested =>
  1565 (types) and ==> (props); the default behaviour is "brackets";
  1566 
  1567 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1568 as assumptions as well;
  1569 
  1570 * system: support Poly/ML 4.0;
  1571 
  1572 * system: isatool install handles KDE version 1 or 2;
  1573 
  1574 
  1575 
  1576 New in Isabelle99-1 (October 2000)
  1577 ----------------------------------
  1578 
  1579 *** Overview of INCOMPATIBILITIES ***
  1580 
  1581 * HOL: simplification of natural numbers is much changed; to partly
  1582 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1583 issue the following ML commands:
  1584 
  1585   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1586   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1587 
  1588 * HOL: simplification no longer dives into case-expressions; this is
  1589 controlled by "t.weak_case_cong" for each datatype t;
  1590 
  1591 * HOL: nat_less_induct renamed to less_induct;
  1592 
  1593 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1594 fixsome to patch .thy and .ML sources automatically;
  1595 
  1596   select_equality  -> some_equality
  1597   select_eq_Ex     -> some_eq_ex
  1598   selectI2EX       -> someI2_ex
  1599   selectI2         -> someI2
  1600   selectI          -> someI
  1601   select1_equality -> some1_equality
  1602   Eps_sym_eq       -> some_sym_eq_trivial
  1603   Eps_eq           -> some_eq_trivial
  1604 
  1605 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1606 
  1607 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1608 instead);
  1609 
  1610 * HOL: the recursion equations generated by 'recdef' are now called
  1611 f.simps instead of f.rules;
  1612 
  1613 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1614 
  1615 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1616 sometimes be needed;
  1617 
  1618 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1619 
  1620 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1621 
  1622 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1623 product is now "<*>" instead of "Times"; the lexicographic product is
  1624 now "<*lex*>" instead of "**";
  1625 
  1626 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1627 of main HOL, but was unused); better use HOL's datatype package;
  1628 
  1629 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1630 the old syntax may be recovered as follows:
  1631 
  1632   syntax (symbols)
  1633     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1634       (infixl "\\<oplus>" 100)
  1635 
  1636 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1637 
  1638 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1639 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1640 internally;
  1641 
  1642 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1643 changed from A/r to A//r;
  1644 
  1645 * ZF: new treatment of arithmetic (nat & int) may break some old
  1646 proofs;
  1647 
  1648 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1649 rulify -> rule_format, elimify -> elim_format, ...);
  1650 
  1651 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1652 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1653 should have to change intro!! to intro? only); replaced "delrule" by
  1654 "rule del";
  1655 
  1656 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1657 
  1658 * Provers: strengthened force_tac by using new first_best_tac;
  1659 
  1660 * LaTeX document preparation: several changes of isabelle.sty (see
  1661 lib/texinputs);
  1662 
  1663 
  1664 *** Document preparation ***
  1665 
  1666 * formal comments (text blocks etc.) in new-style theories may now
  1667 contain antiquotations of thm/prop/term/typ/text to be presented
  1668 according to latex print mode; concrete syntax is like this:
  1669 @{term[show_types] "f(x) = a + x"};
  1670 
  1671 * isatool mkdir provides easy setup of Isabelle session directories,
  1672 including proper document sources;
  1673 
  1674 * generated LaTeX sources are now deleted after successful run
  1675 (isatool document -c); may retain a copy somewhere else via -D option
  1676 of isatool usedir;
  1677 
  1678 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1679 style files, achieving self-contained LaTeX sources and simplifying
  1680 LaTeX debugging;
  1681 
  1682 * old-style theories now produce (crude) LaTeX output as well;
  1683 
  1684 * browser info session directories are now self-contained (may be put
  1685 on WWW server seperately); improved graphs of nested sessions; removed
  1686 graph for 'all sessions';
  1687 
  1688 * several improvements in isabelle style files; \isabellestyle{it}
  1689 produces fake math mode output; \isamarkupheader is now \section by
  1690 default; see lib/texinputs/isabelle.sty etc.;
  1691 
  1692 
  1693 *** Isar ***
  1694 
  1695 * Isar/Pure: local results and corresponding term bindings are now
  1696 subject to Hindley-Milner polymorphism (similar to ML); this
  1697 accommodates incremental type-inference very nicely;
  1698 
  1699 * Isar/Pure: new derived language element 'obtain' supports
  1700 generalized existence reasoning;
  1701 
  1702 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1703 support accumulation of results, without applying any rules yet;
  1704 useful to collect intermediate results without explicit name
  1705 references, and for use with transitivity rules with more than 2
  1706 premises;
  1707 
  1708 * Isar/Pure: scalable support for case-analysis type proofs: new
  1709 'case' language element refers to local contexts symbolically, as
  1710 produced by certain proof methods; internally, case names are attached
  1711 to theorems as "tags";
  1712 
  1713 * Isar/Pure: theory command 'hide' removes declarations from
  1714 class/type/const name spaces;
  1715 
  1716 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1717 indicate potential overloading;
  1718 
  1719 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1720 
  1721 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1722 "{a,b,c}" instead of {a,b,c};
  1723 
  1724 * Isar/Pure now provides its own version of intro/elim/dest
  1725 attributes; useful for building new logics, but beware of confusion
  1726 with the version in Provers/classical;
  1727 
  1728 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1729 case name 'antecedent';
  1730 
  1731 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1732 to the current context is now done automatically);
  1733 
  1734 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1735 for definining proof methods in ML;
  1736 
  1737 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1738 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1739 most cases, one should have to change intro!! to intro? only);
  1740 replaced "delrule" by "rule del";
  1741 
  1742 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1743 'symmetric' attribute (the latter supercedes [RS sym]);
  1744 
  1745 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1746 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1747 well (including splits);
  1748 
  1749 * Isar/Provers: Simplifier and Classical methods now support all kind
  1750 of modifiers used in the past, including 'cong', 'iff', etc.
  1751 
  1752 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1753 of Simplifier and Classical reasoner);
  1754 
  1755 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1756 now support named cases; major packages (inductive, datatype, primrec,
  1757 recdef) support case names and properly name parameters;
  1758 
  1759 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1760 monotonicity conditions are extracted to be proven at end of
  1761 calculations;
  1762 
  1763 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1764 method anyway;
  1765 
  1766 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1767 split_if split_if_asm; datatype package provides theorems foo.splits =
  1768 foo.split foo.split_asm for each datatype;
  1769 
  1770 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1771 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1772 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1773 use "(cases (simplified))" method in proper proof texts);
  1774 
  1775 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1776 
  1777 * Isar: names of theorems etc. may be natural numbers as well;
  1778 
  1779 * Isar: 'pr' command: optional arguments for goals_limit and
  1780 ProofContext.prems_limit; no longer prints theory contexts, but only
  1781 proof states;
  1782 
  1783 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1784 additional print modes to be specified; e.g. "pr(latex)" will print
  1785 proof state according to the Isabelle LaTeX style;
  1786 
  1787 * Isar: improved support for emulating tactic scripts, including proof
  1788 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1789 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1790 (for HOL datatypes);
  1791 
  1792 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1793 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1794 'proof method scripts' have to be in depth-first order;
  1795 
  1796 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1797 
  1798 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1799 should instead use individual commands for printing items
  1800 (print_commands, print_methods etc.);
  1801 
  1802 * Isar: added 'nothing' --- the empty list of theorems;
  1803 
  1804 
  1805 *** HOL ***
  1806 
  1807 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1808 corresponding virtual machine and a specification of its bytecode
  1809 verifier and a lightweight bytecode verifier, including proofs of
  1810 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1811 Cornelia Pusch (see also the homepage of project Bali at
  1812 http://isabelle.in.tum.de/Bali/);
  1813 
  1814 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1815 Clemens Ballarin;
  1816 
  1817 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1818 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1819 Rasmussen;
  1820 
  1821 * HOL/Lattice: fundamental concepts of lattice theory and order
  1822 structures, including duals, properties of bounds versus algebraic
  1823 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1824 Theorem for complete lattices etc.; may also serve as a demonstration
  1825 for abstract algebraic reasoning using axiomatic type classes, and
  1826 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1827 
  1828 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1829 von Oheimb;
  1830 
  1831 * HOL/IMPP: extension of IMP with local variables and mutually
  1832 recursive procedures, by David von Oheimb;
  1833 
  1834 * HOL/Lambda: converted into new-style theory and document;
  1835 
  1836 * HOL/ex/Multiquote: example of multiple nested quotations and
  1837 anti-quotations -- basically a generalized version of de-Bruijn
  1838 representation; very useful in avoiding lifting of operations;
  1839 
  1840 * HOL/record: added general record equality rule to simpset; fixed
  1841 select-update simplification procedure to handle extended records as
  1842 well; admit "r" as field name;
  1843 
  1844 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1845 other numeric types and also as the identity of groups, rings, etc.;
  1846 
  1847 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1848 Types nat and int belong to this axclass;
  1849 
  1850 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1851    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1852    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1853   two terms #m*u and #n*u are replaced by #(m+n)*u
  1854     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1855   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1856     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1857 
  1858 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1859 powerful prover for predicate logic but knows nothing of clasets; see
  1860 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1861 
  1862 * HOL: new version of "case_tac" subsumes both boolean case split and
  1863 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1864 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1865 
  1866 * HOL: simplification no longer dives into case-expressions: only the
  1867 selector expression is simplified, but not the remaining arms; to
  1868 enable full simplification of case-expressions for datatype t, you may
  1869 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1870 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1871 
  1872 * HOL/recdef: the recursion equations generated by 'recdef' for
  1873 function 'f' are now called f.simps instead of f.rules; if all
  1874 termination conditions are proved automatically, these simplification
  1875 rules are added to the simpset, as in primrec; rules may be named
  1876 individually as well, resulting in a separate list of theorems for
  1877 each equation;
  1878 
  1879 * HOL/While is a new theory that provides a while-combinator. It
  1880 permits the definition of tail-recursive functions without the
  1881 provision of a termination measure. The latter is necessary once the
  1882 invariant proof rule for while is applied.
  1883 
  1884 * HOL: new (overloaded) notation for the set of elements below/above
  1885 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1886 
  1887 * HOL: theorems impI, allI, ballI bound as "strip";
  1888 
  1889 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1890 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1891 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1892 
  1893 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1894 
  1895 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1896 main HOL, but was unused);
  1897 
  1898 * HOL: fewer consts declared as global (e.g. have to refer to
  1899 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1900 
  1901 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1902 in case of overlap with user translations (e.g. judgements over
  1903 tuples); (note that the underlying logical represenation is still
  1904 bogus);
  1905 
  1906 
  1907 *** ZF ***
  1908 
  1909 * ZF: simplification automatically cancels common terms in arithmetic
  1910 expressions over nat and int;
  1911 
  1912 * ZF: new treatment of nat to minimize type-checking: all operators
  1913 coerce their operands to a natural number using the function natify,
  1914 making the algebraic laws unconditional;
  1915 
  1916 * ZF: as above, for int: operators coerce their operands to an integer
  1917 using the function intify;
  1918 
  1919 * ZF: the integer library now contains many of the usual laws for the
  1920 orderings, including $<=, and monotonicity laws for $+ and $*;
  1921 
  1922 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1923 simplification;
  1924 
  1925 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1926 to the simplifier and classical reasoner simultaneously;
  1927 
  1928 
  1929 *** General ***
  1930 
  1931 * Provers: blast_tac now handles actual object-logic rules as
  1932 assumptions; note that auto_tac uses blast_tac internally as well;
  1933 
  1934 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1935 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1936 
  1937 * Provers: delrules now handles destruct rules as well (no longer need
  1938 explicit make_elim);
  1939 
  1940 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1941   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1942 use instead the strong form,
  1943   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1944 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1945 from destruct-rules;
  1946 
  1947 * Provers: Simplifier.easy_setup provides a fast path to basic
  1948 Simplifier setup for new object-logics;
  1949 
  1950 * Pure: AST translation rules no longer require constant head on LHS;
  1951 
  1952 * Pure: improved name spaces: ambiguous output is qualified; support
  1953 for hiding of names;
  1954 
  1955 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1956 XSYMBOL_HOME; no longer need to do manual configuration in most
  1957 situations;
  1958 
  1959 * system: compression of ML heaps images may now be controlled via -c
  1960 option of isabelle and isatool usedir (currently only observed by
  1961 Poly/ML);
  1962 
  1963 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1964 useful for remote X11);
  1965 
  1966 * system: provide TAGS file for Isabelle sources;
  1967 
  1968 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1969 order;
  1970 
  1971 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1972 timing flag supersedes proof_timing and Toplevel.trace;
  1973 
  1974 * ML: new combinators |>> and |>>> for incremental transformations
  1975 with secondary results (e.g. certain theory extensions):
  1976 
  1977 * ML: PureThy.add_defs gets additional argument to indicate potential
  1978 overloading (usually false);
  1979 
  1980 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1981 results;
  1982 
  1983 
  1984 
  1985 New in Isabelle99 (October 1999)
  1986 --------------------------------
  1987 
  1988 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1989 
  1990 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1991 are no longer simplified.  (This allows the simplifier to unfold recursive
  1992 functional programs.)  To restore the old behaviour, declare
  1993 
  1994     Delcongs [if_weak_cong];
  1995 
  1996 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1997 complement;
  1998 
  1999 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2000 
  2001 * HOL/datatype: mutual_induct_tac no longer exists --
  2002   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2003 
  2004 * HOL/typedef: fixed type inference for representing set; type
  2005 arguments now have to occur explicitly on the rhs as type constraints;
  2006 
  2007 * ZF: The con_defs part of an inductive definition may no longer refer
  2008 to constants declared in the same theory;
  2009 
  2010 * HOL, ZF: the function mk_cases, generated by the inductive
  2011 definition package, has lost an argument.  To simplify its result, it
  2012 uses the default simpset instead of a supplied list of theorems.
  2013 
  2014 * HOL/List: the constructors of type list are now Nil and Cons;
  2015 
  2016 * Simplifier: the type of the infix ML functions
  2017         setSSolver addSSolver setSolver addSolver
  2018 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2019 for packaging solvers. A solver is created via
  2020         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2021 where the string argument is only a comment.
  2022 
  2023 
  2024 *** Proof tools ***
  2025 
  2026 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2027 decision procedure for linear arithmetic. Currently it is used for
  2028 types `nat', `int', and `real' in HOL (see below); it can, should and
  2029 will be instantiated for other types and logics as well.
  2030 
  2031 * The simplifier now accepts rewrite rules with flexible heads, eg
  2032      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2033   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2034   matching.
  2035 
  2036 
  2037 *** General ***
  2038 
  2039 * New Isabelle/Isar subsystem provides an alternative to traditional
  2040 tactical theorem proving; together with the ProofGeneral/isar user
  2041 interface it offers an interactive environment for developing human
  2042 readable proof documents (Isar == Intelligible semi-automated
  2043 reasoning); for further information see isatool doc isar-ref,
  2044 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2045 
  2046 * improved and simplified presentation of theories: better HTML markup
  2047 (including colors), graph views in several sizes; isatool usedir now
  2048 provides a proper interface for user theories (via -P option); actual
  2049 document preparation based on (PDF)LaTeX is available as well (for
  2050 new-style theories only); see isatool doc system for more information;
  2051 
  2052 * native support for Proof General, both for classic Isabelle and
  2053 Isabelle/Isar;
  2054 
  2055 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2056 using the graph browser tool;
  2057 
  2058 * Isabelle manuals now also available as PDF;
  2059 
  2060 * theory loader rewritten from scratch (may not be fully
  2061 bug-compatible); old loadpath variable has been replaced by show_path,
  2062 add_path, del_path, reset_path functions; new operations such as
  2063 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2064 isatool doc ref);
  2065 
  2066 * improved isatool install: option -k creates KDE application icon,
  2067 option -p DIR installs standalone binaries;
  2068 
  2069 * added ML_PLATFORM setting (useful for cross-platform installations);
  2070 more robust handling of platform specific ML images for SML/NJ;
  2071 
  2072 * the settings environment is now statically scoped, i.e. it is never
  2073 created again in sub-processes invoked from isabelle, isatool, or
  2074 Isabelle;
  2075 
  2076 * path element specification '~~' refers to '$ISABELLE_HOME';
  2077 
  2078 * in locales, the "assumes" and "defines" parts may be omitted if
  2079 empty;
  2080 
  2081 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2082 long arrows);
  2083 
  2084 * new print_mode "HTML";
  2085 
  2086 * new flag show_tags controls display of tags of theorems (which are
  2087 basically just comments that may be attached by some tools);
  2088 
  2089 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2090 mode and goal output format:
  2091 
  2092 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2093 244c244
  2094 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2095 ---
  2096 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2097 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2098 181c181
  2099 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2100 ---
  2101 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2102 
  2103 * function bind_thms stores lists of theorems (cf. bind_thm);
  2104 
  2105 * new shorthand tactics ftac, eatac, datac, fatac;
  2106 
  2107 * qed (and friends) now accept "" as result name; in that case the
  2108 theorem is not stored, but proper checks and presentation of the
  2109 result still apply;
  2110 
  2111 * theorem database now also indexes constants "Trueprop", "all",
  2112 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2113 
  2114 
  2115 *** HOL ***
  2116 
  2117 ** HOL arithmetic **
  2118 
  2119 * There are now decision procedures for linear arithmetic over nat and
  2120 int:
  2121 
  2122 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2123 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2124 are treated as atomic; subformulae not involving type `nat' or `int'
  2125 are ignored; quantified subformulae are ignored unless they are
  2126 positive universal or negative existential. The tactic has to be
  2127 invoked by hand and can be a little bit slow. In particular, the
  2128 running time is exponential in the number of occurrences of `min' and
  2129 `max', and `-' on `nat'.
  2130 
  2131 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2132 (negated) (in)equalities among the premises and the conclusion into
  2133 account (i.e. no compound formulae) and does not know about `min' and
  2134 `max', and `-' on `nat'. It is fast and is used automatically by the
  2135 simplifier.
  2136 
  2137 NB: At the moment, these decision procedures do not cope with mixed
  2138 nat/int formulae where the two parts interact, such as `m < n ==>
  2139 int(m) < int(n)'.
  2140 
  2141 * HOL/Numeral provides a generic theory of numerals (encoded
  2142 efficiently as bit strings); setup for types nat/int/real is in place;
  2143 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2144 int, existing theories and proof scripts may require a few additional
  2145 type constraints;
  2146 
  2147 * integer division and remainder can now be performed on constant
  2148 arguments;
  2149 
  2150 * many properties of integer multiplication, division and remainder
  2151 are now available;
  2152 
  2153 * An interface to the Stanford Validity Checker (SVC) is available through the
  2154 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2155 are proved automatically.  SVC must be installed separately, and its results
  2156 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2157 invocation of the underlying oracle).  For SVC see
  2158   http://verify.stanford.edu/SVC
  2159 
  2160 * IsaMakefile: the HOL-Real target now builds an actual image;
  2161 
  2162 
  2163 ** HOL misc **
  2164 
  2165 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2166 (in Isabelle/Isar) -- by Gertrud Bauer;
  2167 
  2168 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2169 analysis for assembly languages with subtypes;
  2170 
  2171 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2172 -- avoids syntactic ambiguities and treats state, transition, and
  2173 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2174 changed syntax and (many) tactics;
  2175 
  2176 * HOL/inductive: Now also handles more general introduction rules such
  2177   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2178   theorems are now maintained within the theory (maintained via the
  2179   "mono" attribute);
  2180 
  2181 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2182   (using function types) such as
  2183 
  2184   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2185 
  2186 * HOL/record: record_simproc (part of the default simpset) takes care
  2187 of selectors applied to updated records; record_split_tac is no longer
  2188 part of the default claset; update_defs may now be removed from the
  2189 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2190 
  2191   claset_ref () := claset() addSWrapper record_split_wrapper;
  2192   Delsimprocs [record_simproc]
  2193 
  2194 * HOL/typedef: fixed type inference for representing set; type
  2195 arguments now have to occur explicitly on the rhs as type constraints;
  2196 
  2197 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2198 names rather than an ML expression;
  2199 
  2200 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2201 supplied later.  Program schemes can be defined, such as
  2202     "While B C s = (if B s then While B C (C s) else s)"
  2203 where the well-founded relation can be chosen after B and C have been given.
  2204 
  2205 * HOL/List: the constructors of type list are now Nil and Cons;
  2206 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2207 course, ML tools referring to List.list.op # etc. have to be adapted;
  2208 
  2209 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2210 disabled by default; run isabelle with option -m HOL to get back to
  2211 the original Gordon/HOL-style output;
  2212 
  2213 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2214 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2215 
  2216 * HOL basic syntax simplified (more orthogonal): all variants of
  2217 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2218 Eps operator is provided as well: "SOME x. P[x]";
  2219 
  2220 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2221 
  2222 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2223 thus available for user theories;
  2224 
  2225 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2226 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2227 time;
  2228 
  2229 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2230 several times and then mp;
  2231 
  2232 
  2233 *** LK ***
  2234 
  2235 * the notation <<...>> is now available as a notation for sequences of
  2236 formulas;
  2237 
  2238 * the simplifier is now installed
  2239 
  2240 * the axiom system has been generalized (thanks to Soren Heilmann)
  2241 
  2242 * the classical reasoner now has a default rule database
  2243 
  2244 
  2245 *** ZF ***
  2246 
  2247 * new primrec section allows primitive recursive functions to be given
  2248 directly (as in HOL) over datatypes and the natural numbers;
  2249 
  2250 * new tactics induct_tac and exhaust_tac for induction (or case
  2251 analysis) over datatypes and the natural numbers;
  2252 
  2253 * the datatype declaration of type T now defines the recursor T_rec;
  2254 
  2255 * simplification automatically does freeness reasoning for datatype
  2256 constructors;
  2257 
  2258 * automatic type-inference, with AddTCs command to insert new
  2259 type-checking rules;
  2260 
  2261 * datatype introduction rules are now added as Safe Introduction rules
  2262 to the claset;
  2263 
  2264 * the syntax "if P then x else y" is now available in addition to
  2265 if(P,x,y);
  2266 
  2267 
  2268 *** Internal programming interfaces ***
  2269 
  2270 * tuned simplifier trace output; new flag debug_simp;
  2271 
  2272 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2273 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2274 
  2275 * AxClass.axclass_tac lost the theory argument;
  2276 
  2277 * tuned current_goals_markers semantics: begin / end goal avoids
  2278 printing empty lines;
  2279 
  2280 * removed prs and prs_fn hook, which was broken because it did not
  2281 include \n in its semantics, forcing writeln to add one
  2282 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2283 string -> unit if you really want to output text without newline;
  2284 
  2285 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2286 plain output, interface builders may have to enable 'isabelle_font'
  2287 mode to get Isabelle font glyphs as before;
  2288 
  2289 * refined token_translation interface; INCOMPATIBILITY: output length
  2290 now of type real instead of int;
  2291 
  2292 * theory loader actions may be traced via new ThyInfo.add_hook
  2293 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2294 your own database of information attached to *whole* theories -- as
  2295 opposed to intra-theory data slots offered via TheoryDataFun;
  2296 
  2297 * proper handling of dangling sort hypotheses (at last!);
  2298 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2299 extra sort hypotheses that can be witnessed from the type signature;
  2300 the force_strip_shyps flag is gone, any remaining shyps are simply
  2301 left in the theorem (with a warning issued by strip_shyps_warning);
  2302 
  2303 
  2304 
  2305 New in Isabelle98-1 (October 1998)
  2306 ----------------------------------
  2307 
  2308 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2309 
  2310 * several changes of automated proof tools;
  2311 
  2312 * HOL: major changes to the inductive and datatype packages, including
  2313 some minor incompatibilities of theory syntax;
  2314 
  2315 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2316 called `inj_on';
  2317 
  2318 * HOL: removed duplicate thms in Arith:
  2319   less_imp_add_less  should be replaced by  trans_less_add1
  2320   le_imp_add_le      should be replaced by  trans_le_add1
  2321 
  2322 * HOL: unary minus is now overloaded (new type constraints may be
  2323 required);
  2324 
  2325 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2326 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2327 now taken as an integer constant.
  2328 
  2329 * Pure: ML function 'theory_of' renamed to 'theory';
  2330 
  2331 
  2332 *** Proof tools ***
  2333 
  2334 * Simplifier:
  2335   1. Asm_full_simp_tac is now more aggressive.
  2336      1. It will sometimes reorient premises if that increases their power to
  2337         simplify.
  2338      2. It does no longer proceed strictly from left to right but may also
  2339         rotate premises to achieve further simplification.
  2340      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2341      old Asm_full_simp_tac in that it does not rotate premises.
  2342   2. The simplifier now knows a little bit about nat-arithmetic.
  2343 
  2344 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2345 allows for selected deletion of wrappers, by introduction of names for
  2346 wrapper functionals.  This implies that addbefore, addSbefore,
  2347 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2348 and that adding two tactics with the same name overwrites the first
  2349 one (emitting a warning).
  2350   type wrapper = (int -> tactic) -> (int -> tactic)
  2351   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2352   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2353   delWrapper, delSWrapper: claset *  string            -> claset
  2354   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2355 
  2356 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2357 semantics; addbefore now affects only the unsafe part of step_tac
  2358 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2359 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2360 by Force_tac;
  2361 
  2362 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2363 compWrapper; added safe wrapper (and access functions for it);
  2364 
  2365 * HOL/split_all_tac is now much faster and fails if there is nothing
  2366 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2367 and the names of the automatically generated variables have changed.
  2368 split_all_tac has moved within claset() from unsafe wrappers to safe
  2369 wrappers, which means that !!-bound variables are split much more
  2370 aggressively, and safe_tac and clarify_tac now split such variables.
  2371 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2372 Note: the same holds for record_split_tac, which does the job of
  2373 split_all_tac for record fields.
  2374 
  2375 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2376 permanently to the default simpset using Addsplits just like
  2377 Addsimps. They can be removed via Delsplits just like
  2378 Delsimps. Lower-case versions are also available.
  2379 
  2380 * HOL/Simplifier: The rule split_if is now part of the default
  2381 simpset. This means that the simplifier will eliminate all occurrences
  2382 of if-then-else in the conclusion of a goal. To prevent this, you can
  2383 either remove split_if completely from the default simpset by
  2384 `Delsplits [split_if]' or remove it in a specific call of the
  2385 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2386 other case splitting rules to/from the default simpset: every datatype
  2387 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2388 t is the name of the datatype).
  2389 
  2390 * Classical reasoner / Simplifier combination: new force_tac (and
  2391 derivatives Force_tac, force) combines rewriting and classical
  2392 reasoning (and whatever other tools) similarly to auto_tac, but is
  2393 aimed to solve the given subgoal completely.
  2394 
  2395 
  2396 *** General ***
  2397 
  2398 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2399 and `goalw': the theory is no longer needed as an explicit argument -
  2400 the current theory context is used; assumptions are no longer returned
  2401 at the ML-level unless one of them starts with ==> or !!; it is
  2402 recommended to convert to these new commands using isatool fixgoal
  2403 (backup your sources first!);
  2404 
  2405 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2406 the current theory context, and 'theory' to lookup stored theories;
  2407 
  2408 * new theory section 'locale' for declaring constants, assumptions and
  2409 definitions that have local scope;
  2410 
  2411 * new theory section 'nonterminals' for purely syntactic types;
  2412 
  2413 * new theory section 'setup' for generic ML setup functions
  2414 (e.g. package initialization);
  2415 
  2416 * the distribution now includes Isabelle icons: see
  2417 lib/logo/isabelle-{small,tiny}.xpm;
  2418 
  2419 * isatool install - install binaries with absolute references to
  2420 ISABELLE_HOME/bin;
  2421 
  2422 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2423 
  2424 * print mode 'emacs' reserved for Isamode;
  2425 
  2426 * support multiple print (ast) translations per constant name;
  2427 
  2428 * theorems involving oracles are now printed with a suffixed [!];
  2429 
  2430 
  2431 *** HOL ***
  2432 
  2433 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2434 
  2435 * HOL/inductive package reorganized and improved: now supports mutual
  2436 definitions such as
  2437 
  2438   inductive EVEN ODD
  2439     intrs
  2440       null "0 : EVEN"
  2441       oddI "n : EVEN ==> Suc n : ODD"
  2442       evenI "n : ODD ==> Suc n : EVEN"
  2443 
  2444 new theorem list "elims" contains an elimination rule for each of the
  2445 recursive sets; inductive definitions now handle disjunctive premises
  2446 correctly (also ZF);
  2447 
  2448 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2449 "mutual_induct" no longer exists - the induction rule is always
  2450 contained in "induct";
  2451 
  2452 
  2453 * HOL/datatype package re-implemented and greatly improved: now
  2454 supports mutually recursive datatypes such as
  2455 
  2456   datatype
  2457     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2458             | SUM ('a aexp) ('a aexp)
  2459             | DIFF ('a aexp) ('a aexp)
  2460             | NUM 'a
  2461   and
  2462     'a bexp = LESS ('a aexp) ('a aexp)
  2463             | AND ('a bexp) ('a bexp)
  2464             | OR ('a bexp) ('a bexp)
  2465 
  2466 as well as indirectly recursive datatypes such as
  2467 
  2468   datatype
  2469     ('a, 'b) term = Var 'a
  2470                   | App 'b ((('a, 'b) term) list)
  2471 
  2472 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2473 induction on mutually / indirectly recursive datatypes.
  2474 
  2475 Primrec equations are now stored in theory and can be accessed via
  2476 <function_name>.simps.
  2477 
  2478 INCOMPATIBILITIES:
  2479 
  2480   - Theories using datatypes must now have theory Datatype as an
  2481     ancestor.
  2482   - The specific <typename>.induct_tac no longer exists - use the
  2483     generic induct_tac instead.
  2484   - natE has been renamed to nat.exhaust - use exhaust_tac
  2485     instead of res_inst_tac ... natE. Note that the variable
  2486     names in nat.exhaust differ from the names in natE, this
  2487     may cause some "fragile" proofs to fail.
  2488   - The theorems split_<typename>_case and split_<typename>_case_asm
  2489     have been renamed to <typename>.split and <typename>.split_asm.
  2490   - Since default sorts of type variables are now handled correctly,
  2491     some datatype definitions may have to be annotated with explicit
  2492     sort constraints.
  2493   - Primrec definitions no longer require function name and type
  2494     of recursive argument.
  2495 
  2496 Consider using isatool fixdatatype to adapt your theories and proof
  2497 scripts to the new package (backup your sources first!).
  2498 
  2499 
  2500 * HOL/record package: considerably improved implementation; now
  2501 includes concrete syntax for record types, terms, updates; theorems
  2502 for surjective pairing and splitting !!-bound record variables; proof
  2503 support is as follows:
  2504 
  2505   1) standard conversions (selectors or updates applied to record
  2506 constructor terms) are part of the standard simpset;
  2507 
  2508   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2509 made part of standard simpset and claset via addIffs;
  2510 
  2511   3) a tactic for record field splitting (record_split_tac) is part of
  2512 the standard claset (addSWrapper);
  2513 
  2514 To get a better idea about these rules you may retrieve them via
  2515 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2516 the name of your record type.
  2517 
  2518 The split tactic 3) conceptually simplifies by the following rule:
  2519 
  2520   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2521 
  2522 Thus any record variable that is bound by meta-all will automatically
  2523 blow up into some record constructor term, consequently the
  2524 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2525 solve record problems automatically.
  2526 
  2527 
  2528 * reorganized the main HOL image: HOL/Integ and String loaded by
  2529 default; theory Main includes everything;
  2530 
  2531 * automatic simplification of integer sums and comparisons, using cancellation;
  2532 
  2533 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2534 
  2535 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2536 
  2537 * many new identities for unions, intersections, set difference, etc.;
  2538 
  2539 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2540 called split_if, split_split, split_sum_case and split_nat_case (to go
  2541 with add/delsplits);
  2542 
  2543 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2544 (?x::unit) = (); this is made part of the default simpset, which COULD
  2545 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2546 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2547 unit_abs_eta_conv is added in order to counter the effect of
  2548 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2549 %u.f();
  2550 
  2551 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2552 makes more sense);
  2553 
  2554 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2555   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2556   disjointness reasoning but breaking a few old proofs.
  2557 
  2558 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2559 to 'converse' from 'inverse' (for compatibility with ZF and some
  2560 literature);
  2561 
  2562 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2563 the well-founded relation;
  2564 
  2565 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2566     Compl A.  The "Compl" syntax remains available as input syntax for this
  2567     release ONLY.
  2568 
  2569 * HOL/Update: new theory of function updates:
  2570     f(a:=b) == %x. if x=a then b else f x
  2571 may also be iterated as in f(a:=b,c:=d,...);
  2572 
  2573 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2574 
  2575 * HOL/List:
  2576   - new function list_update written xs[i:=v] that updates the i-th
  2577     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2578   - new function `upt' written [i..j(] which generates the list
  2579     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2580     bound write [i..j], which is a shorthand for [i..j+1(].
  2581   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2582 
  2583 * HOL/Arith:
  2584   - removed 'pred' (predecessor) function;
  2585   - generalized some theorems about n-1;
  2586   - many new laws about "div" and "mod";
  2587   - new laws about greatest common divisors (see theory ex/Primes);
  2588 
  2589 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2590 instead of "inverse";
  2591 
  2592 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2593   of the multiset ordering;
  2594 
  2595 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2596   (not included by default);
  2597 
  2598 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2599 
  2600 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2601   programs, i.e. different program variables may have different types.
  2602 
  2603 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2604   [previously, this check worked only if the rewrite rule was unconditional]
  2605   Now rew can involve either definitions or equalities (either == or =).
  2606 
  2607 
  2608 *** ZF ***
  2609 
  2610 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2611   only the theorems proved on ZF.ML;
  2612 
  2613 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2614   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2615   disjointness reasoning but breaking a few old proofs.
  2616 
  2617 * ZF/Update: new theory of function updates
  2618     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2619   may also be iterated as in f(a:=b,c:=d,...);
  2620 
  2621 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2622 
  2623 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2624   [previously, this check worked only if the rewrite rule was unconditional]
  2625   Now rew can involve either definitions or equalities (either == or =).
  2626 
  2627 * case_tac provided for compatibility with HOL
  2628     (like the old excluded_middle_tac, but with subgoals swapped)
  2629 
  2630 
  2631 *** Internal programming interfaces ***
  2632 
  2633 * Pure: several new basic modules made available for general use, see
  2634 also src/Pure/README;
  2635 
  2636 * improved the theory data mechanism to support encapsulation (data
  2637 kind name replaced by private Object.kind, acting as authorization
  2638 key); new type-safe user interface via functor TheoryDataFun; generic
  2639 print_data function becomes basically useless;
  2640 
  2641 * removed global_names compatibility flag -- all theory declarations
  2642 are qualified by default;
  2643 
  2644 * module Pure/Syntax now offers quote / antiquote translation
  2645 functions (useful for Hoare logic etc. with implicit dependencies);
  2646 see HOL/ex/Antiquote for an example use;
  2647 
  2648 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2649 cterm -> thm;
  2650 
  2651 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2652 subgoal;
  2653 
  2654 * Display.print_goals function moved to Locale.print_goals;
  2655 
  2656 * standard print function for goals supports current_goals_markers
  2657 variable for marking begin of proof, end of proof, start of goal; the
  2658 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2659 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2660 for example;
  2661 
  2662 
  2663 
  2664 New in Isabelle98 (January 1998)
  2665 --------------------------------
  2666 
  2667 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2668 
  2669 * changed lexical syntax of terms / types: dots made part of long
  2670 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2671 
  2672 * simpset (and claset) reference variable replaced by functions
  2673 simpset / simpset_ref;
  2674 
  2675 * no longer supports theory aliases (via merge) and non-trivial
  2676 implicit merge of thms' signatures;
  2677 
  2678 * most internal names of constants changed due to qualified names;
  2679 
  2680 * changed Pure/Sequence interface (see Pure/seq.ML);
  2681 
  2682 
  2683 *** General Changes ***
  2684 
  2685 * hierachically structured name spaces (for consts, types, axms, thms
  2686 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2687 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2688 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2689 long_names for fully qualified output names; NOTE: ML programs
  2690 (special tactics, packages etc.) referring to internal names may have
  2691 to be adapted to cope with fully qualified names; in case of severe
  2692 backward campatibility problems try setting 'global_names' at compile
  2693 time to have enrything declared within a flat name space; one may also
  2694 fine tune name declarations in theories via the 'global' and 'local'
  2695 section;
  2696 
  2697 * reimplemented the implicit simpset and claset using the new anytype
  2698 data filed in signatures; references simpset:simpset ref etc. are
  2699 replaced by functions simpset:unit->simpset and
  2700 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2701 to patch your ML files accordingly;
  2702 
  2703 * HTML output now includes theory graph data for display with Java
  2704 applet or isatool browser; data generated automatically via isatool
  2705 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2706 
  2707 * defs may now be conditional; improved rewrite_goals_tac to handle
  2708 conditional equations;
  2709 
  2710 * defs now admits additional type arguments, using TYPE('a) syntax;
  2711 
  2712 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2713 creates a new theory node; implicit merge of thms' signatures is
  2714 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2715 transfer:theory->thm->thm in (rare) cases;
  2716 
  2717 * improved handling of draft signatures / theories; draft thms (and
  2718 ctyps, cterms) are automatically promoted to real ones;
  2719 
  2720 * slightly changed interfaces for oracles: admit many per theory, named
  2721 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2722 
  2723 * print_goals: optional output of const types (set show_consts and
  2724 show_types);
  2725 
  2726 * improved output of warnings (###) and errors (***);
  2727 
  2728 * subgoal_tac displays a warning if the new subgoal has type variables;
  2729 
  2730 * removed old README and Makefiles;
  2731 
  2732 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2733 
  2734 * removed obsolete init_pps and init_database;
  2735 
  2736 * deleted the obsolete tactical STATE, which was declared by
  2737     fun STATE tacfun st = tacfun st st;
  2738 
  2739 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2740 (which abbreviates $HOME);
  2741 
  2742 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2743 use isatool fixseq to adapt your ML programs (this works for fully
  2744 qualified references to the Sequence structure only!);
  2745 
  2746 * use_thy no longer requires writable current directory; it always
  2747 reloads .ML *and* .thy file, if either one is out of date;
  2748 
  2749 
  2750 *** Classical Reasoner ***
  2751 
  2752 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2753 tactics that use classical reasoning to simplify a subgoal without
  2754 splitting it into several subgoals;
  2755 
  2756 * Safe_tac: like safe_tac but uses the default claset;
  2757 
  2758 
  2759 *** Simplifier ***
  2760 
  2761 * added simplification meta rules:
  2762     (asm_)(full_)simplify: simpset -> thm -> thm;
  2763 
  2764 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2765 logics (again);
  2766 
  2767 * added prems argument to simplification procedures;
  2768 
  2769 * HOL, FOL, ZF: added infix function `addsplits':
  2770   instead of `<simpset> setloop (split_tac <thms>)'
  2771   you can simply write `<simpset> addsplits <thms>'
  2772 
  2773 
  2774 *** Syntax ***
  2775 
  2776 * TYPE('a) syntax for type reflection terms;
  2777 
  2778 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2779 
  2780 * pretty printer: changed order of mixfix annotation preference (again!);
  2781 
  2782 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2783 
  2784 
  2785 *** HOL ***
  2786 
  2787 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2788   with `addloop' of the simplifier to faciliate case splitting in premises.
  2789 
  2790 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2791 
  2792 * HOL/Auth: new protocol proofs including some for the Internet
  2793   protocol TLS;
  2794 
  2795 * HOL/Map: new theory of `maps' a la VDM;
  2796 
  2797 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2798 cancelling out common nat summands from =, <, <= (in)equalities, or
  2799 differences; simplification procedures nat_cancel_factor for
  2800 cancelling common factor from =, <, <= (in)equalities over natural
  2801 sums; nat_cancel contains both kinds of procedures, it is installed by
  2802 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2803 
  2804 * HOL/simplifier: terms of the form
  2805   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2806   are rewritten to
  2807   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2808   and those of the form
  2809   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2810   are rewritten to
  2811   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2812 
  2813 * HOL/datatype
  2814   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2815 
  2816   P(t_case f1 ... fn x) =
  2817      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2818         ...
  2819        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2820      )
  2821 
  2822   and a theorem `split_t_case_asm' of the form
  2823 
  2824   P(t_case f1 ... fn x) =
  2825     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2826         ...
  2827        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2828      )
  2829   which can be added to a simpset via `addsplits'. The existing theorems
  2830   expand_list_case and expand_option_case have been renamed to
  2831   split_list_case and split_option_case.
  2832 
  2833 * HOL/Arithmetic:
  2834   - `pred n' is automatically converted to `n-1'.
  2835     Users are strongly encouraged not to use `pred' any longer,
  2836     because it will disappear altogether at some point.
  2837   - Users are strongly encouraged to write "0 < n" rather than
  2838     "n ~= 0". Theorems and proof tools have been modified towards this
  2839     `standard'.
  2840 
  2841 * HOL/Lists:
  2842   the function "set_of_list" has been renamed "set" (and its theorems too);
  2843   the function "nth" now takes its arguments in the reverse order and
  2844   has acquired the infix notation "!" as in "xs!n".
  2845 
  2846 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2847 
  2848 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2849   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2850 
  2851 * HOL/record: extensible records with schematic structural subtyping
  2852 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2853 still lacks various theorems and concrete record syntax;
  2854 
  2855 
  2856 *** HOLCF ***
  2857 
  2858 * removed "axioms" and "generated by" sections;
  2859 
  2860 * replaced "ops" section by extended "consts" section, which is capable of
  2861   handling the continuous function space "->" directly;
  2862 
  2863 * domain package:
  2864   . proves theorems immediately and stores them in the theory,
  2865   . creates hierachical name space,
  2866   . now uses normal mixfix annotations (instead of cinfix...),
  2867   . minor changes to some names and values (for consistency),
  2868   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2869   . separator between mutual domain defs: changed "," to "and",
  2870   . improved handling of sort constraints;  now they have to
  2871     appear on the left-hand side of the equations only;
  2872 
  2873 * fixed LAM <x,y,zs>.b syntax;
  2874 
  2875 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2876 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2877 
  2878 
  2879 *** FOL and ZF ***
  2880 
  2881 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2882   with `addloop' of the simplifier to faciliate case splitting in premises.
  2883 
  2884 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2885 in HOL, they strip ALL and --> from proved theorems;
  2886 
  2887 
  2888 
  2889 New in Isabelle94-8 (May 1997)
  2890 ------------------------------
  2891 
  2892 *** General Changes ***
  2893 
  2894 * new utilities to build / run / maintain Isabelle etc. (in parts
  2895 still somewhat experimental); old Makefiles etc. still functional;
  2896 
  2897 * new 'Isabelle System Manual';
  2898 
  2899 * INSTALL text, together with ./configure and ./build scripts;
  2900 
  2901 * reimplemented type inference for greater efficiency, better error
  2902 messages and clean internal interface;
  2903 
  2904 * prlim command for dealing with lots of subgoals (an easier way of
  2905 setting goals_limit);
  2906 
  2907 
  2908 *** Syntax ***
  2909 
  2910 * supports alternative (named) syntax tables (parser and pretty
  2911 printer); internal interface is provided by add_modesyntax(_i);
  2912 
  2913 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2914 be used in conjunction with the Isabelle symbol font; uses the
  2915 "symbols" syntax table;
  2916 
  2917 * added token_translation interface (may translate name tokens in
  2918 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2919 the current print_mode); IMPORTANT: user print translation functions
  2920 are responsible for marking newly introduced bounds
  2921 (Syntax.mark_boundT);
  2922 
  2923 * token translations for modes "xterm" and "xterm_color" that display
  2924 names in bold, underline etc. or colors (which requires a color
  2925 version of xterm);
  2926 
  2927 * infixes may now be declared with names independent of their syntax;
  2928 
  2929 * added typed_print_translation (like print_translation, but may
  2930 access type of constant);
  2931 
  2932 
  2933 *** Classical Reasoner ***
  2934 
  2935 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2936 some limitations.  Blast_tac...
  2937   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2938   + ignores elimination rules that don't have the correct format
  2939         (the conclusion MUST be a formula variable)
  2940   + ignores types, which can make HOL proofs fail
  2941   + rules must not require higher-order unification, e.g. apply_type in ZF
  2942     [message "Function Var's argument not a bound variable" relates to this]
  2943   + its proof strategy is more general but can actually be slower
  2944 
  2945 * substitution with equality assumptions no longer permutes other
  2946 assumptions;
  2947 
  2948 * minor changes in semantics of addafter (now called addaltern); renamed
  2949 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2950 (and access functions for it);
  2951 
  2952 * improved combination of classical reasoner and simplifier:
  2953   + functions for handling clasimpsets
  2954   + improvement of addss: now the simplifier is called _after_ the
  2955     safe steps.
  2956   + safe variant of addss called addSss: uses safe simplifications
  2957     _during_ the safe steps. It is more complete as it allows multiple
  2958     instantiations of unknowns (e.g. with slow_tac).
  2959 
  2960 *** Simplifier ***
  2961 
  2962 * added interface for simplification procedures (functions that
  2963 produce *proven* rewrite rules on the fly, depending on current
  2964 redex);
  2965 
  2966 * ordering on terms as parameter (used for ordered rewriting);
  2967 
  2968 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2969 
  2970 * the solver is now split into a safe and an unsafe part.
  2971 This should be invisible for the normal user, except that the
  2972 functions setsolver and addsolver have been renamed to setSolver and
  2973 addSolver; added safe_asm_full_simp_tac;
  2974 
  2975 
  2976 *** HOL ***
  2977 
  2978 * a generic induction tactic `induct_tac' which works for all datatypes and
  2979 also for type `nat';
  2980 
  2981 * a generic case distinction tactic `exhaust_tac' which works for all
  2982 datatypes and also for type `nat';
  2983 
  2984 * each datatype comes with a function `size';
  2985 
  2986 * patterns in case expressions allow tuple patterns as arguments to
  2987 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2988 
  2989 * primrec now also works with type nat;
  2990 
  2991 * recdef: a new declaration form, allows general recursive functions to be
  2992 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2993 
  2994 * the constant for negation has been renamed from "not" to "Not" to
  2995 harmonize with FOL, ZF, LK, etc.;
  2996 
  2997 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2998 infinite lists;
  2999 
  3000 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3001 
  3002 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3003 problems in commutative rings, using axiomatic type classes for + and *;
  3004 
  3005 * more examples in HOL/MiniML and HOL/Auth;
  3006 
  3007 * more default rewrite rules for quantifiers, union/intersection;
  3008 
  3009 * a new constant `arbitrary == @x.False';
  3010 
  3011 * HOLCF/IOA replaces old HOL/IOA;
  3012 
  3013 * HOLCF changes: derived all rules and arities
  3014   + axiomatic type classes instead of classes
  3015   + typedef instead of faking type definitions
  3016   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3017   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3018   + eliminated the types void, one, tr
  3019   + use unit lift and bool lift (with translations) instead of one and tr
  3020   + eliminated blift from Lift3.thy (use Def instead of blift)
  3021   all eliminated rules are derived as theorems --> no visible changes ;
  3022 
  3023 
  3024 *** ZF ***
  3025 
  3026 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3027 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3028 as ZF_cs addSIs [equalityI];
  3029 
  3030 
  3031 
  3032 New in Isabelle94-7 (November 96)
  3033 ---------------------------------
  3034 
  3035 * allowing negative levels (as offsets) in prlev and choplev;
  3036 
  3037 * super-linear speedup for large simplifications;
  3038 
  3039 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3040 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3041 FAIL); can suppress it using the command Delsimps (ex_simps @
  3042 all_simps); De Morgan laws are also now included, by default;
  3043 
  3044 * improved printing of ==>  :  ~:
  3045 
  3046 * new object-logic "Sequents" adds linear logic, while replacing LK
  3047 and Modal (thanks to Sara Kalvala);
  3048 
  3049 * HOL/Auth: correctness proofs for authentication protocols;
  3050 
  3051 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3052 examples on HOL/Auth);
  3053 
  3054 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3055 the rewriter and classical reasoner simultaneously;
  3056 
  3057 * function uresult no longer returns theorems in "standard" format;
  3058 regain previous version by: val uresult = standard o uresult;
  3059 
  3060 
  3061 
  3062 New in Isabelle94-6
  3063 -------------------
  3064 
  3065 * oracles -- these establish an interface between Isabelle and trusted
  3066 external reasoners, which may deliver results as theorems;
  3067 
  3068 * proof objects (in particular record all uses of oracles);
  3069 
  3070 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3071 
  3072 * "constdefs" section in theory files;
  3073 
  3074 * "primrec" section (HOL) no longer requires names;
  3075 
  3076 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3077 
  3078 
  3079 
  3080 New in Isabelle94-5
  3081 -------------------
  3082 
  3083 * reduced space requirements;
  3084 
  3085 * automatic HTML generation from theories;
  3086 
  3087 * theory files no longer require "..." (quotes) around most types;
  3088 
  3089 * new examples, including two proofs of the Church-Rosser theorem;
  3090 
  3091 * non-curried (1994) version of HOL is no longer distributed;
  3092 
  3093 
  3094 
  3095 New in Isabelle94-4
  3096 -------------------
  3097 
  3098 * greatly reduced space requirements;
  3099 
  3100 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3101 
  3102 * searchable theorem database (see the section "Retrieving theorems" on
  3103 page 8 of the Reference Manual);
  3104 
  3105 * new examples, including Grabczewski's monumental case study of the
  3106 Axiom of Choice;
  3107 
  3108 * The previous version of HOL renamed to Old_HOL;
  3109 
  3110 * The new version of HOL (previously called CHOL) uses a curried syntax
  3111 for functions.  Application looks like f a b instead of f(a,b);
  3112 
  3113 * Mutually recursive inductive definitions finally work in HOL;
  3114 
  3115 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3116 translates to the operator "split";
  3117 
  3118 
  3119 
  3120 New in Isabelle94-3
  3121 -------------------
  3122 
  3123 * new infix operator, addss, allowing the classical reasoner to
  3124 perform simplification at each step of its search.  Example:
  3125         fast_tac (cs addss ss)
  3126 
  3127 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3128 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3129 look like (a,b) instead of <a,b>;
  3130 
  3131 * PLEASE NOTE: CHOL will eventually replace HOL!
  3132 
  3133 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3134 It translates to the operator "split".  A new theory of integers is available;
  3135 
  3136 * In ZF, integer numerals now denote two's-complement binary integers.
  3137 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3138 
  3139 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3140 of the Axiom of Choice;
  3141 
  3142 
  3143 
  3144 New in Isabelle94-2
  3145 -------------------
  3146 
  3147 * Significantly faster resolution;
  3148 
  3149 * the different sections in a .thy file can now be mixed and repeated
  3150 freely;
  3151 
  3152 * Database of theorems for FOL, HOL and ZF.  New
  3153 commands including qed, qed_goal and bind_thm store theorems in the database.
  3154 
  3155 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3156 a given theory (thms_of), or find out what theory a theorem was proved in
  3157 (theory_of_thm);
  3158 
  3159 * Bugs fixed in the inductive definition and datatype packages;
  3160 
  3161 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3162 and HOL_dup_cs obsolete;
  3163 
  3164 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3165 have been removed;
  3166 
  3167 * Simpler definition of function space in ZF;
  3168 
  3169 * new results about cardinal and ordinal arithmetic in ZF;
  3170 
  3171 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3172 types;
  3173 
  3174 
  3175 $Id$