NEWS
author haftmann
Thu Jun 16 10:42:55 2005 +0200 (2005-06-16)
changeset 16408 9bbaa5695691
parent 16373 9d020423093b
child 16456 451f1c46d4ca
permissions -rw-r--r--
isa-migrate ++
     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.  Note that there is no change in
    21 ancient non-Isar theories.
    22 
    23 * Theory loader: parent theories can now also be referred to via
    24 relative and absolute paths.
    25 
    26 * Improved version of thms_containing searches for a list of criteria
    27 instead of a list of constants. Known criteria are: intro, elim, dest,
    28 name:string, simp:term, and any term. Criteria can be preceded by '-'
    29 to select theorems that do not match. Intro, elim, dest select
    30 theorems that match the current goal, name:s selects theorems whose
    31 fully qualified name contain s, and simp:term selects all
    32 simplification rules whose lhs match term.  Any other term is
    33 interpreted as pattern and selects all theorems matching the
    34 pattern. Available in ProofGeneral under 'ProofGeneral -> Find
    35 Theorems' or C-c C-f.  Example:
    36 
    37   C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
    38 
    39 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
    40 matching the current goal as introduction rule and not having "HOL."
    41 in their name (i.e. not being defined in theory HOL).
    42 
    43 
    44 *** Document preparation ***
    45 
    46 * Commands 'display_drafts' and 'print_drafts' perform simple output
    47 of raw sources.  Only those symbols that do not require additional
    48 LaTeX packages (depending on comments in isabellesym.sty) are
    49 displayed properly, everything else is left verbatim.  isatool display
    50 and isatool print are used as front ends (these are subject to the
    51 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
    52 
    53 * There is now a flag to control hiding of proofs and some other
    54 commands (such as 'ML' or 'parse/print_translation') in document
    55 output.  Hiding is enabled by default, and can be disabled by the
    56 option '-H false' of isatool usedir or by resetting the reference
    57 variable IsarOutput.hide_commands in ML.  Additional commands to be
    58 hidden may be declared using IsarOutput.add_hidden_commands.
    59 
    60 * Several new antiquotation:
    61 
    62   @{term_type term} prints a term with its type annotated;
    63 
    64   @{typeof term} prints the type of a term;
    65 
    66   @{const const} is the same as @{term const}, but checks that the
    67   argument is a known logical constant;
    68 
    69   @{term_style style term} and @{thm_style style thm} print a term or
    70   theorem applying a "style" to it
    71 
    72 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
    73 definitions, equations, inequations etc., 'concl' printing only the
    74 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem9'
    75 to print the specified premise.  TermStyle.add_style provides an ML
    76 interface for introducing further styles.  See also the "LaTeX Sugar"
    77 document practical applications.
    78 
    79 
    80 *** Pure ***
    81 
    82 * Considerably improved version of 'constdefs' command.  Now performs
    83 automatic type-inference of declared constants; additional support for
    84 local structure declarations (cf. locales and HOL records), see also
    85 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
    86 sequential dependencies of definitions within a single 'constdefs'
    87 section; moreover, the declared name needs to be an identifier.  If
    88 all fails, consider to fall back on 'consts' and 'defs' separately.
    89 
    90 * Improved indexed syntax and implicit structures.  First of all,
    91 indexed syntax provides a notational device for subscripted
    92 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    93 expressions.  Secondly, in a local context with structure
    94 declarations, number indexes \<^sub>n or the empty index (default
    95 number 1) refer to a certain fixed variable implicitly; option
    96 show_structs controls printing of implicit structures.  Typical
    97 applications of these concepts involve record types and locales.
    98 
    99 * New command 'no_syntax' removes grammar declarations (and
   100 translations) resulting from the given syntax specification, which is
   101 interpreted in the same manner as for the 'syntax' command.
   102 
   103 * 'Advanced' translation functions (parse_translation etc.) may depend
   104 on the signature of the theory context being presently used for
   105 parsing/printing, see also isar-ref manual.
   106 
   107 * Improved internal renaming of symbolic identifiers -- attach primes
   108 instead of base 26 numbers.
   109 
   110 * New flag show_question_marks controls printing of leading question
   111 marks in schematic variable names.
   112 
   113 * In schematic variable names, *any* symbol following \<^isub> or
   114 \<^isup> is now treated as part of the base name.  For example, the
   115 following works without printing of awkward ".0" indexes:
   116 
   117   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   118     by simp
   119 
   120 * Inner syntax includes (*(*nested*) comments*).
   121 
   122 * Pretty pinter now supports unbreakable blocks, specified in mixfix
   123 annotations as "(00...)".
   124 
   125 * Clear separation of logical types and nonterminals, where the latter
   126 may only occur in 'syntax' specifications or type abbreviations.
   127 Before that distinction was only partially implemented via type class
   128 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   129 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   130 exotic syntax specifications may require further adaption
   131 (e.g. Cube/Base.thy).
   132 
   133 * Removed obsolete type class "logic", use the top sort {} instead.
   134 Note that non-logical types should be declared as 'nonterminals'
   135 rather than 'types'.  INCOMPATIBILITY for new object-logic
   136 specifications.
   137 
   138 * Simplifier: can now control the depth to which conditional rewriting
   139 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   140 Limit.
   141 
   142 * Simplifier: simplification procedures may now take the current
   143 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   144 interface), which is very useful for calling the Simplifier
   145 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   146 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   147 low-level mk_simproc no longer applies Logic.varify internally, to
   148 allow for use in a context of fixed variables.
   149 
   150 * thin_tac now works even if the assumption being deleted contains !!
   151 or ==>.  More generally, erule now works even if the major premise of
   152 the elimination rule contains !! or ==>.
   153 
   154 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   155 from Pure, which contains all common declarations already.  Both
   156 theories are defined via plain Isabelle/Isar .thy files.
   157 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   158 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   159 use isatool fixcpure to adapt your theory and ML sources.
   160 
   161 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   162 selections of theorems in named facts via index ranges.
   163 
   164 
   165 *** Locales ***
   166   
   167 * New commands for the interpretation of locale expressions in
   168 theories ('interpretation') and proof contexts ('interpret').  These
   169 take an instantiation of the locale parameters and compute proof
   170 obligations from the instantiated specification.  After the
   171 obligations have been discharged, the instantiated theorems of the
   172 locale are added to the theory or proof context.  Interpretation is
   173 smart in that already active interpretations do not occur in proof
   174 obligations, neither are instantiated theorems stored in duplicate.
   175 Use print_interps to inspect active interpretations of a particular
   176 locale.  For details, see the Isar Reference manual.
   177 
   178 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   179 'interpret' instead.
   180 
   181 * Proper static binding of attribute syntax -- i.e. types / terms /
   182 facts mentioned as arguments are always those of the locale definition
   183 context, independently of the context of later invocations.  Moreover,
   184 locale operations (renaming and type / term instantiation) are applied
   185 to attribute arguments as expected.
   186 
   187 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   188 actual attributes; rare situations may require Attrib.attribute to
   189 embed those attributes into Attrib.src that lack concrete syntax.
   190 Attribute implementations need to cooperate properly with the static
   191 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   192 Attrib.XXX_thm etc. already do the right thing without further
   193 intervention.  Only unusual applications -- such as "where" or "of"
   194 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   195 on the context and the facts involved -- may have to assign parsed
   196 values to argument tokens explicitly.
   197 
   198 * New context element "constrains" adds type constraints to parameters --
   199 there is no logical significance.
   200 
   201 * Context expressions: renaming parameters permits syntax
   202 redeclaration as well.
   203 
   204 * Locale definition: 'includes' now disallowed.
   205 
   206 * Changed parameter management in theorem generation for long goal
   207 statements with 'includes'.  INCOMPATIBILITY: produces a different
   208 theorem statement in rare situations.
   209 
   210 * Attributes 'induct' and 'cases': type or set names may now be
   211 locally fixed variables as well.
   212 
   213 * Antiquotations now provide the option 'locale=NAME' to specify an
   214 alternative context used for evaluating and printing the subsequent
   215 argument, as in @{thm [locale=LC] fold_commute}, for example.
   216 
   217 
   218 *** Provers ***
   219 
   220 * Provers/hypsubst.ML: improved version of the subst method, for
   221 single-step rewriting: it now works in bound variable contexts. New is
   222 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   223 rewrite a different subterm than the original subst method, which is
   224 still available as 'simplesubst'.
   225 
   226 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   227 and quasi orders.
   228 
   229 * Provers/trancl.ML: new transitivity reasoner for transitive and
   230 reflexive-transitive closure of relations.
   231 
   232 * Provers/blast.ML: new reference depth_limit to make blast's depth
   233 limit (previously hard-coded with a value of 20) user-definable.
   234 
   235 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   236 is peformed already.  Object-logics merely need to finish their
   237 initial simpset configuration as before.  INCOMPATIBILITY.
   238 
   239 
   240 *** HOL ***
   241 
   242 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   243 
   244   syntax (epsilon)
   245     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   246 
   247 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   248 and x-symbol; use option '-m epsilon' to get it actually printed.
   249 Moreover, the mathematically important symbolic identifier \<epsilon>
   250 becomes available as variable, constant etc.  INCOMPATIBILITY,
   251 
   252 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   253 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   254 is \<ge>.
   255 
   256 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   257 instead of ":".
   258 
   259 * theory SetInterval: changed the syntax for open intervals:
   260 
   261   Old       New
   262   {..n(}    {..<n}
   263   {)n..}    {n<..}
   264   {m..n(}   {m..<n}
   265   {)m..n}   {m<..n}
   266   {)m..n(}  {m<..<n}
   267 
   268 The old syntax is still supported but will disappear in the next
   269 release.  For conversion use the following Emacs search and replace
   270 patterns (these are not perfect but work quite well):
   271 
   272   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   273   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   274 
   275 * theory Finite_Set: changed the syntax for 'setsum', summation over
   276 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   277 now either "SUM x:A. e" or "\<Sum>x \<in> A. e".
   278 
   279 Some new syntax forms are available:
   280 
   281   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   282   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   283   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   284   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   285 
   286 The latter form "\<Sum>x < k. e" used to be based on a separate
   287 function "Summation", which has been discontinued.
   288 
   289 * theory Finite_Set: in structured induction proofs, the insert case
   290 is now 'case (insert x F)' instead of the old counterintuitive 'case
   291 (insert F x)'.
   292 
   293 * The 'refute' command has been extended to support a much larger
   294 fragment of HOL, including axiomatic type classes, constdefs and
   295 typedefs, inductive datatypes and recursion.
   296 
   297 * Datatype induction via method 'induct' now preserves the name of the
   298 induction variable. For example, when proving P(xs::'a list) by
   299 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   300 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   301 in unstructured proof scripts.
   302 
   303 * Reworked implementation of records.  Improved scalability for
   304 records with many fields, avoiding performance problems for type
   305 inference. Records are no longer composed of nested field types, but
   306 of nested extension types. Therefore the record type only grows linear
   307 in the number of extensions and not in the number of fields.  The
   308 top-level (users) view on records is preserved.  Potential
   309 INCOMPATIBILITY only in strange cases, where the theory depends on the
   310 old record representation. The type generated for a record is called
   311 <record_name>_ext_type.
   312 
   313 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   314 proofs triggered by a record definition or a simproc (if
   315 quick_and_dirty is enabled).  Definitions of large records can take
   316 quite long.
   317 
   318 New simproc record_upd_simproc for simplification of multiple record
   319 updates enabled by default.  Moreover, trivial updates are also
   320 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   321 occasionally, since simplification is more powerful by default.
   322 
   323 * Simplifier: automatically reasons about transitivity chains
   324 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   325 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   326 old proofs break occasionally as simplification may now solve more
   327 goals than previously.
   328 
   329 * Simplifier: converts x <= y into x = y if assumption y <= x is
   330 present.  Works for all partial orders (class "order"), in particular
   331 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   332 just like y <= x.
   333 
   334 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   335 bound variable or a constant then the let is unfolded.  Otherwise
   336 first a is simplified to b, and then f b is simplified to g. If
   337 possible we abstract b from g arriving at "let x = b in h x",
   338 otherwise we unfold the let and arrive at g.  The simproc can be
   339 enabled/disabled by the reference use_let_simproc.  Potential
   340 INCOMPATIBILITY since simplification is more powerful by default.
   341 
   342 
   343 *** HOLCF ***
   344 
   345 * HOLCF: discontinued special version of 'constdefs' (which used to
   346 support continuous functions) in favor of the general Pure one with
   347 full type-inference.
   348 
   349 
   350 *** ZF ***
   351 
   352 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
   353 including the First Isomorphism Theorem (on quotienting by the kernel
   354 of a homomorphism).
   355 
   356 * ZF/Simplifier: install second copy of type solver that actually
   357 makes use of TC rules declared to Isar proof contexts (or locales);
   358 the old version is still required for ML proof scripts.
   359 
   360 
   361 *** ML ***
   362 
   363 * Pure/library.ML no longer defines its own option datatype, but uses
   364 that of the SML basis, which has constructors NONE and SOME instead of
   365 None and Some, as well as exception Option.Option instead of OPTION.
   366 The functions the, if_none, is_some, is_none have been adapted
   367 accordingly, while Option.map replaces apsome.
   368 
   369 * The exception LIST has been given up in favour of the standard
   370 exceptions Empty and Subscript, as well as Library.UnequalLengths.
   371 Function like Library.hd and Library.tl are superceded by the standard
   372 hd and tl functions etc.
   373 
   374 A number of basic functions are now no longer exported to the ML
   375 toplevel, as they are variants of standard functions.  The following
   376 suggests how one can translate existing code:
   377 
   378     rev_append xs ys = List.revAppend (xs, ys)
   379     nth_elem (i, xs) = List.nth (xs, i)
   380     last_elem xs = List.last xs
   381     flat xss = List.concat xss
   382     seq fs = List.app fs
   383     partition P xs = List.partition P xs
   384     filter P xs = List.filter P xs
   385     mapfilter f xs = List.mapPartial f xs
   386 
   387 * Pure: output via the Isabelle channels of writeln/warning/error
   388 etc. is now passed through Output.output, with a hook for arbitrary
   389 transformations depending on the print_mode (cf. Output.add_mode --
   390 the first active mode that provides a output function wins).  Already
   391 formatted output may be embedded into further text via Output.raw; the
   392 result of Pretty.string_of/str_of and derived functions
   393 (string_of_term/cterm/thm etc.) is already marked raw to accommodate
   394 easy composition of diagnostic messages etc.  Programmers rarely need
   395 to care about Output.output or Output.raw at all, with some notable
   396 exceptions: Output.output is required when bypassing the standard
   397 channels (writeln etc.), or in token translations to produce properly
   398 formatted results; Output.raw is required when capturing already
   399 output material that will eventually be presented to the user a second
   400 time.  For the default print mode, both Output.output and Output.raw
   401 have no effect.
   402 
   403 * Pure: print_tac now outputs the goal through the trace channel.
   404 
   405 * Isar debugging: new reference Toplevel.debug; default false.  Set to
   406 make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   407 
   408 * Pure: name spaces have been refined, with significant changes of the
   409 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   410 to extern(_table).  The plain name entry path is superceded by a
   411 general 'naming' context, which also includes the 'policy' to produce
   412 a fully qualified name and external accesses of a fully qualified
   413 name; NameSpace.extend is superceded by context dependent
   414 Sign.declare_name.  Several theory and proof context operations modify
   415 the naming context.  Especially note Theory.restore_naming and
   416 ProofContext.restore_naming to get back to a sane state; note that
   417 Theory.add_path is no longer sufficient to recover from
   418 Theory.absolute_path in particular.
   419 
   420 * Pure: new flags short_names (default false) and unique_names
   421 (default true) for controlling output of qualified names.  If
   422 short_names is set, names are printed unqualified.  If unique_names is
   423 reset, the name prefix is reduced to the minimum required to achieve
   424 the original result when interning again, even if there is an overlap
   425 with earlier declarations.
   426 
   427 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
   428 typeK, constK, axiomK, oracleK), but provide explicit operations for
   429 any of these kinds.  For example, Sign.intern typeK is now
   430 Sign.intern_type, Theory.hide_space Sign.typeK is now
   431 Theory.hide_types.  Also note that former
   432 Theory.hide_classes/types/consts are now
   433 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
   434 internalize their arguments!  INCOMPATIBILITY.
   435 
   436 * Pure: cases produced by proof methods specify options, where NONE
   437 means to remove case bindings -- INCOMPATIBILITY in
   438 (RAW_)METHOD_CASES.
   439 
   440 * Pure: the following operations retrieve axioms or theorems from a
   441 theory node or theory hierarchy, respectively:
   442 
   443   Theory.axioms_of: theory -> (string * term) list
   444   Theory.all_axioms_of: theory -> (string * term) list
   445   PureThy.thms_of: theory -> (string * thm) list
   446   PureThy.all_thms_of: theory -> (string * thm) list
   447 
   448 * Provers: Simplifier and Classical Reasoner now support proof context
   449 dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   450 components are stored in the theory and patched into the
   451 simpset/claset when used in an Isar proof context.  Context dependent
   452 components are maintained by the following theory operations:
   453 
   454   Simplifier.add_context_simprocs
   455   Simplifier.del_context_simprocs
   456   Simplifier.set_context_subgoaler
   457   Simplifier.reset_context_subgoaler
   458   Simplifier.add_context_looper
   459   Simplifier.del_context_looper
   460   Simplifier.add_context_unsafe_solver
   461   Simplifier.add_context_safe_solver
   462 
   463   Classical.add_context_safe_wrapper
   464   Classical.del_context_safe_wrapper
   465   Classical.add_context_unsafe_wrapper
   466   Classical.del_context_unsafe_wrapper
   467 
   468 IMPORTANT NOTE: proof tools (methods etc.) need to use
   469 local_simpset_of and local_claset_of to instead of the primitive
   470 Simplifier.get_local_simpset and Classical.get_local_claset,
   471 respectively, in order to see the context dependent fields!
   472 
   473 * File.sysify_path and File.quote_sysify path have been replaced by
   474 File.platform_path and File.shell_path (with appropriate hooks).  This
   475 provides a clean interface for unusual systems where the internal and
   476 external process view of file names are different.
   477 
   478 
   479 *** System ***
   480 
   481 * Allow symlinks to all proper Isabelle executables (Isabelle,
   482 isabelle, isatool etc.).
   483 
   484 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   485 isatool doc, isatool mkdir, display_drafts etc.).
   486 
   487 * isatool usedir: option -f allows specification of the ML file to be
   488 used by Isabelle; default is ROOT.ML.
   489 
   490 * New isatool version outputs the version identifier of the Isabelle
   491 distribution being used.
   492 
   493 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
   494 (containing Boolean satisfiability problems) into Isabelle/HOL
   495 theories.
   496 
   497 
   498 
   499 New in Isabelle2004 (April 2004)
   500 --------------------------------
   501 
   502 *** General ***
   503 
   504 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   505   Replaces linorder.ML.
   506 
   507 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   508   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   509   (\<a>...\<z>), are now considered normal letters, and can therefore
   510   be used anywhere where an ASCII letter (a...zA...Z) has until
   511   now. COMPATIBILITY: This obviously changes the parsing of some
   512   terms, especially where a symbol has been used as a binder, say
   513   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   514   as an identifier.  Fix it by inserting a space around former
   515   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   516   existing theory and ML files.
   517 
   518 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   519 
   520 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   521   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   522   a normal (but invisible) letter. For multiple letter subscripts repeat
   523   \<^isub> like this: x\<^isub>1\<^isub>2.
   524 
   525 * Pure: There are now sub-/superscripts that can span more than one
   526   character. Text between \<^bsub> and \<^esub> is set in subscript in
   527   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   528   superscript. The new control characters are not identifier parts.
   529 
   530 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   531   content of "..." to the latex file instead of \isacntrl... . The "..."
   532   may consist of any printable characters excluding the end bracket >.
   533 
   534 * Pure: Using new Isar command "finalconsts" (or the ML functions
   535   Theory.add_finals or Theory.add_finals_i) it is now possible to
   536   declare constants "final", which prevents their being given a definition
   537   later.  It is useful for constants whose behaviour is fixed axiomatically
   538   rather than definitionally, such as the meta-logic connectives.
   539 
   540 * Pure: 'instance' now handles general arities with general sorts
   541   (i.e. intersections of classes),
   542 
   543 * Presentation: generated HTML now uses a CSS style sheet to make layout
   544   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   545   It can be changed to alter the colors/layout of generated pages.
   546 
   547 
   548 *** Isar ***
   549 
   550 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   551   cut_tac, subgoal_tac and thin_tac:
   552   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   553     locales are no longer forced to write Isar proof scripts.
   554     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   555     emulations.
   556   - INCOMPATIBILITY: names of variables to be instantiated may no
   557     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   558     This is consistent with the instantiation attribute "where".
   559 
   560 * Attributes "where" and "of":
   561   - Now take type variables of instantiated theorem into account when reading
   562     the instantiation string.  This fixes a bug that caused instantiated
   563     theorems to have too special types in some circumstances.
   564   - "where" permits explicit instantiations of type variables.
   565 
   566 * Calculation commands "moreover" and "also" no longer interfere with
   567   current facts ("this"), admitting arbitrary combinations with "then"
   568   and derived forms.
   569 
   570 * Locales:
   571   - Goal statements involving the context element "includes" no longer
   572     generate theorems with internal delta predicates (those ending on
   573     "_axioms") in the premise.
   574     Resolve particular premise with <locale>.intro to obtain old form.
   575   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   576     specification and "includes" elements in goal statement.
   577   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   578     [intro?] and [elim?] (respectively) by default.
   579   - Experimental command for instantiation of locales in proof contexts:
   580         instantiate <label>[<attrs>]: <loc>
   581     Instantiates locale <loc> and adds all its theorems to the current context
   582     taking into account their attributes.  Label and attrs are optional
   583     modifiers, like in theorem declarations.  If present, names of
   584     instantiated theorems are qualified with <label>, and the attributes
   585     <attrs> are applied after any attributes these theorems might have already.
   586       If the locale has assumptions, a chained fact of the form
   587     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   588     are derived.  The command does not support old-style locales declared
   589     with "locale (open)".
   590       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   591 
   592 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   593   (Isar) contexts.
   594 
   595 
   596 *** HOL ***
   597 
   598 * Proof import: new image HOL4 contains the imported library from
   599   the HOL4 system with about 2500 theorems. It is imported by
   600   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   601   can be used like any other Isabelle image.  See
   602   HOL/Import/HOL/README for more information.
   603 
   604 * Simplifier:
   605   - Much improved handling of linear and partial orders.
   606     Reasoners for linear and partial orders are set up for type classes
   607     "linorder" and "order" respectively, and are added to the default simpset
   608     as solvers.  This means that the simplifier can build transitivity chains
   609     to solve goals from the assumptions.
   610   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   611     of blast or auto after simplification become unnecessary because the goal
   612     is solved by simplification already.
   613 
   614 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   615     all proved in axiomatic type classes for semirings, rings and fields.
   616 
   617 * Numerics:
   618   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   619     now formalized using the Ring_and_Field theory mentioned above.
   620   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   621     than before, because now they are set up once in a generic manner.
   622   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   623     Look for the general versions in Ring_and_Field (and Power if they concern
   624     exponentiation).
   625 
   626 * Type "rat" of the rational numbers is now available in HOL-Complex.
   627 
   628 * Records:
   629   - Record types are now by default printed with their type abbreviation
   630     instead of the list of all field types. This can be configured via
   631     the reference "print_record_type_abbr".
   632   - Simproc "record_upd_simproc" for simplification of multiple updates added
   633     (not enabled by default).
   634   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   635     EX x. x = sel r to True (not enabled by default).
   636   - Tactic "record_split_simp_tac" to split and simplify records added.
   637 
   638 * 'specification' command added, allowing for definition by
   639   specification.  There is also an 'ax_specification' command that
   640   introduces the new constants axiomatically.
   641 
   642 * arith(_tac) is now able to generate counterexamples for reals as well.
   643 
   644 * HOL-Algebra: new locale "ring" for non-commutative rings.
   645 
   646 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   647   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   648 
   649 * HOL-Matrix: a first theory for matrices in HOL with an application of
   650   matrix theory to linear programming.
   651 
   652 * Unions and Intersections:
   653   The latex output syntax of UN and INT has been changed
   654   from "\Union x \in A. B" to "\Union_{x \in A} B"
   655   i.e. the index formulae has become a subscript.
   656   Similarly for "\Union x. B", and for \Inter instead of \Union.
   657 
   658 * Unions and Intersections over Intervals:
   659   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   660   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   661   like in normal math, and corresponding versions for < and for intersection.
   662 
   663 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   664   lexicographic dictonary ordering has been added as "lexord".
   665 
   666 * ML: the legacy theory structures Int and List have been removed. They had
   667   conflicted with ML Basis Library structures having the same names.
   668 
   669 * 'refute' command added to search for (finite) countermodels.  Only works
   670   for a fragment of HOL.  The installation of an external SAT solver is
   671   highly recommended.  See "HOL/Refute.thy" for details.
   672 
   673 * 'quickcheck' command: Allows to find counterexamples by evaluating
   674   formulae under an assignment of free variables to random values.
   675   In contrast to 'refute', it can deal with inductive datatypes,
   676   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   677   for examples.
   678 
   679 
   680 *** HOLCF ***
   681 
   682 * Streams now come with concatenation and are part of the HOLCF image
   683 
   684 
   685 
   686 New in Isabelle2003 (May 2003)
   687 ------------------------------
   688 
   689 *** General ***
   690 
   691 * Provers/simplifier:
   692 
   693   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   694     Assumptions are now subject to complete mutual simplification,
   695     not just from left to right. The simplifier now preserves
   696     the order of assumptions.
   697 
   698     Potential INCOMPATIBILITY:
   699 
   700     -- simp sometimes diverges where the old version did
   701        not, e.g. invoking simp on the goal
   702 
   703         [| P (f x); y = x; f x = f y |] ==> Q
   704 
   705        now gives rise to the infinite reduction sequence
   706 
   707         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   708 
   709        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   710        kind of problem.
   711 
   712     -- Tactics combining classical reasoner and simplification (such as auto)
   713        are also affected by this change, because many of them rely on
   714        simp. They may sometimes diverge as well or yield a different numbers
   715        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   716        in case of problems. Sometimes subsequent calls to the classical
   717        reasoner will fail because a preceeding call to the simplifier too
   718        eagerly simplified the goal, e.g. deleted redundant premises.
   719 
   720   - The simplifier trace now shows the names of the applied rewrite rules
   721 
   722   - You can limit the number of recursive invocations of the simplifier
   723     during conditional rewriting (where the simplifie tries to solve the
   724     conditions before applying the rewrite rule):
   725     ML "simp_depth_limit := n"
   726     where n is an integer. Thus you can force termination where previously
   727     the simplifier would diverge.
   728 
   729   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   730 
   731   - No longer aborts on failed congruence proof.  Instead, the
   732     congruence is ignored.
   733 
   734 * Pure: New generic framework for extracting programs from constructive
   735   proofs. See HOL/Extraction.thy for an example instantiation, as well
   736   as HOL/Extraction for some case studies.
   737 
   738 * Pure: The main goal of the proof state is no longer shown by default, only
   739 the subgoals. This behaviour is controlled by a new flag.
   740    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   741 (ML: Proof.show_main_goal).
   742 
   743 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   744 rules whose conclusion matches subgoal 1:
   745       PG menu: Isabelle/Isar -> Show me -> matching rules
   746 The rules are ordered by how closely they match the subgoal.
   747 In particular, rules that solve a subgoal outright are displayed first
   748 (or rather last, the way they are printed).
   749 (ML: ProofGeneral.print_intros())
   750 
   751 * Pure: New flag trace_unify_fail causes unification to print
   752 diagnostic information (PG: in trace buffer) when it fails. This is
   753 useful for figuring out why single step proofs like rule, erule or
   754 assumption failed.
   755 
   756 * Pure: Locale specifications now produce predicate definitions
   757 according to the body of text (covering assumptions modulo local
   758 definitions); predicate "loc_axioms" covers newly introduced text,
   759 while "loc" is cumulative wrt. all included locale expressions; the
   760 latter view is presented only on export into the global theory
   761 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   762 on the old view without predicates;
   763 
   764 * Pure: predefined locales "var" and "struct" are useful for sharing
   765 parameters (as in CASL, for example); just specify something like
   766 ``var x + var y + struct M'' as import;
   767 
   768 * Pure: improved thms_containing: proper indexing of facts instead of
   769 raw theorems; check validity of results wrt. current name space;
   770 include local facts of proof configuration (also covers active
   771 locales), cover fixed variables in index; may use "_" in term
   772 specification; an optional limit for the number of printed facts may
   773 be given (the default is 40);
   774 
   775 * Pure: disallow duplicate fact bindings within new-style theory files
   776 (batch-mode only);
   777 
   778 * Provers: improved induct method: assumptions introduced by case
   779 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   780 the goal statement); "foo" still refers to all facts collectively;
   781 
   782 * Provers: the function blast.overloaded has been removed: all constants
   783 are regarded as potentially overloaded, which improves robustness in exchange
   784 for slight decrease in efficiency;
   785 
   786 * Provers/linorder: New generic prover for transitivity reasoning over
   787 linear orders.  Note: this prover is not efficient!
   788 
   789 * Isar: preview of problems to finish 'show' now produce an error
   790 rather than just a warning (in interactive mode);
   791 
   792 
   793 *** HOL ***
   794 
   795 * arith(_tac)
   796 
   797  - Produces a counter example if it cannot prove a goal.
   798    Note that the counter example may be spurious if the goal is not a formula
   799    of quantifier-free linear arithmetic.
   800    In ProofGeneral the counter example appears in the trace buffer.
   801 
   802  - Knows about div k and mod k where k is a numeral of type nat or int.
   803 
   804  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   805    linear arithmetic fails. This takes account of quantifiers and divisibility.
   806    Presburger arithmetic can also be called explicitly via presburger(_tac).
   807 
   808 * simp's arithmetic capabilities have been enhanced a bit: it now
   809 takes ~= in premises into account (by performing a case split);
   810 
   811 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   812 are distributed over a sum of terms;
   813 
   814 * New tactic "trans_tac" and method "trans" instantiate
   815 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   816 "<=", "<" and "=").
   817 
   818 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   819 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   820 
   821 * 'typedef' command has new option "open" to suppress the set
   822 definition;
   823 
   824 * functions Min and Max on finite sets have been introduced (theory
   825 Finite_Set);
   826 
   827 * attribute [symmetric] now works for relations as well; it turns
   828 (x,y) : R^-1 into (y,x) : R, and vice versa;
   829 
   830 * induct over a !!-quantified statement (say !!x1..xn):
   831   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   832 
   833 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   834 %x. None. Warning: empty_def now refers to the previously hidden definition
   835 of the empty set.
   836 
   837 * Algebra: formalization of classical algebra.  Intended as base for
   838 any algebraic development in Isabelle.  Currently covers group theory
   839 (up to Sylow's theorem) and ring theory (Universal Property of
   840 Univariate Polynomials).  Contributions welcome;
   841 
   842 * GroupTheory: deleted, since its material has been moved to Algebra;
   843 
   844 * Complex: new directory of the complex numbers with numeric constants,
   845 nonstandard complex numbers, and some complex analysis, standard and
   846 nonstandard (Jacques Fleuriot);
   847 
   848 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   849 
   850 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   851 Fleuriot);
   852 
   853 * Real/HahnBanach: updated and adapted to locales;
   854 
   855 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   856 Gray and Kramer);
   857 
   858 * UNITY: added the Meier-Sanders theory of progress sets;
   859 
   860 * MicroJava: bytecode verifier and lightweight bytecode verifier
   861 as abstract algorithms, instantiated to the JVM;
   862 
   863 * Bali: Java source language formalization. Type system, operational
   864 semantics, axiomatic semantics. Supported language features:
   865 classes, interfaces, objects,virtual methods, static methods,
   866 static/instance fields, arrays, access modifiers, definite
   867 assignment, exceptions.
   868 
   869 
   870 *** ZF ***
   871 
   872 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   873 universe, etc.);
   874 
   875 * Main ZF: virtually all theories converted to new-style format;
   876 
   877 
   878 *** ML ***
   879 
   880 * Pure: Tactic.prove provides sane interface for internal proofs;
   881 omits the infamous "standard" operation, so this is more appropriate
   882 than prove_goalw_cterm in many situations (e.g. in simprocs);
   883 
   884 * Pure: improved error reporting of simprocs;
   885 
   886 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   887 up simprocs;
   888 
   889 
   890 *** Document preparation ***
   891 
   892 * uses \par instead of \\ for line breaks in theory text. This may
   893 shift some page breaks in large documents. To get the old behaviour
   894 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   895 
   896 * minimized dependencies of isabelle.sty and isabellesym.sty on
   897 other packages
   898 
   899 * \<euro> now needs package babel/greek instead of marvosym (which
   900 broke \Rightarrow)
   901 
   902 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   903 textcomp package)
   904 
   905 
   906 
   907 New in Isabelle2002 (March 2002)
   908 --------------------------------
   909 
   910 *** Document preparation ***
   911 
   912 * greatly simplified document preparation setup, including more
   913 graceful interpretation of isatool usedir -i/-d/-D options, and more
   914 instructive isatool mkdir; users should basically be able to get
   915 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   916 users may run a separate document processing stage manually like this:
   917 "isatool usedir -D output HOL Test && isatool document Test/output";
   918 
   919 * theory dependency graph may now be incorporated into documents;
   920 isatool usedir -g true will produce session_graph.eps/.pdf for use
   921 with \includegraphics of LaTeX;
   922 
   923 * proper spacing of consecutive markup elements, especially text
   924 blocks after section headings;
   925 
   926 * support bold style (for single symbols only), input syntax is like
   927 this: "\<^bold>\<alpha>" or "\<^bold>A";
   928 
   929 * \<bullet> is now output as bold \cdot by default, which looks much
   930 better in printed text;
   931 
   932 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   933 note that these symbols are currently unavailable in Proof General /
   934 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   935 
   936 * isatool latex no longer depends on changed TEXINPUTS, instead
   937 isatool document copies the Isabelle style files to the target
   938 location;
   939 
   940 
   941 *** Isar ***
   942 
   943 * Pure/Provers: improved proof by cases and induction;
   944   - 'case' command admits impromptu naming of parameters (such as
   945     "case (Suc n)");
   946   - 'induct' method divinates rule instantiation from the inductive
   947     claim; no longer requires excessive ?P bindings for proper
   948     instantiation of cases;
   949   - 'induct' method properly enumerates all possibilities of set/type
   950     rules; as a consequence facts may be also passed through *type*
   951     rules without further ado;
   952   - 'induct' method now derives symbolic cases from the *rulified*
   953     rule (before it used to rulify cases stemming from the internal
   954     atomized version); this means that the context of a non-atomic
   955     statement becomes is included in the hypothesis, avoiding the
   956     slightly cumbersome show "PROP ?case" form;
   957   - 'induct' may now use elim-style induction rules without chaining
   958     facts, using ``missing'' premises from the goal state; this allows
   959     rules stemming from inductive sets to be applied in unstructured
   960     scripts, while still benefitting from proper handling of non-atomic
   961     statements; NB: major inductive premises need to be put first, all
   962     the rest of the goal is passed through the induction;
   963   - 'induct' proper support for mutual induction involving non-atomic
   964     rule statements (uses the new concept of simultaneous goals, see
   965     below);
   966   - append all possible rule selections, but only use the first
   967     success (no backtracking);
   968   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   969   - undeclared rule case names default to numbers 1, 2, 3, ...;
   970   - added 'print_induct_rules' (covered by help item in recent Proof
   971     General versions);
   972   - moved induct/cases attributes to Pure, methods to Provers;
   973   - generic method setup instantiated for FOL and HOL;
   974 
   975 * Pure: support multiple simultaneous goal statements, for example
   976 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   977 meta-level mechanism, this acts as if several individual goals had
   978 been stated separately; in particular common proof methods need to be
   979 repeated in order to cover all claims; note that a single elimination
   980 step is *not* sufficient to establish the two conjunctions, so this
   981 fails:
   982 
   983   assume "A & B" then have A and B ..   (*".." fails*)
   984 
   985 better use "obtain" in situations as above; alternative refer to
   986 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   987 
   988 * Pure: proper integration with ``locales''; unlike the original
   989 version by Florian Kammller, Isar locales package high-level proof
   990 contexts rather than raw logical ones (e.g. we admit to include
   991 attributes everywhere); operations on locales include merge and
   992 rename; support for implicit arguments (``structures''); simultaneous
   993 type-inference over imports and text; see also HOL/ex/Locales.thy for
   994 some examples;
   995 
   996 * Pure: the following commands have been ``localized'', supporting a
   997 target locale specification "(in name)": 'lemma', 'theorem',
   998 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   999 stored both within the locale and at the theory level (exported and
  1000 qualified by the locale name);
  1001 
  1002 * Pure: theory goals may now be specified in ``long'' form, with
  1003 ad-hoc contexts consisting of arbitrary locale elements. for example
  1004 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1005 definitions may be given, too); the result is a meta-level rule with
  1006 the context elements being discharged in the obvious way;
  1007 
  1008 * Pure: new proof command 'using' allows to augment currently used
  1009 facts after a goal statement ('using' is syntactically analogous to
  1010 'apply', but acts on the goal's facts only); this allows chained facts
  1011 to be separated into parts given before and after a claim, as in
  1012 ``from a and b have C using d and e <proof>'';
  1013 
  1014 * Pure: renamed "antecedent" case to "rule_context";
  1015 
  1016 * Pure: new 'judgment' command records explicit information about the
  1017 object-logic embedding (used by several tools internally); no longer
  1018 use hard-wired "Trueprop";
  1019 
  1020 * Pure: added 'corollary' command;
  1021 
  1022 * Pure: fixed 'token_translation' command;
  1023 
  1024 * Pure: removed obsolete 'exported' attribute;
  1025 
  1026 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1027 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1028 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1029 
  1030 * Pure: method 'atomize' presents local goal premises as object-level
  1031 statements (atomic meta-level propositions); setup controlled via
  1032 rewrite rules declarations of 'atomize' attribute; example
  1033 application: 'induct' method with proper rule statements in improper
  1034 proof *scripts*;
  1035 
  1036 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1037 now consider the syntactic context of assumptions, giving a better
  1038 chance to get type-inference of the arguments right (this is
  1039 especially important for locales);
  1040 
  1041 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1042 mode;
  1043 
  1044 * Pure/obtain: the formal conclusion "thesis", being marked as
  1045 ``internal'', may no longer be reference directly in the text;
  1046 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1047 situations;
  1048 
  1049 * Pure: generic 'sym' attribute which declares a rule both as pure
  1050 'elim?' and for the 'symmetric' operation;
  1051 
  1052 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1053 text; the fixed correlation with particular command syntax has been
  1054 discontinued;
  1055 
  1056 * Pure: new method 'rules' is particularly well-suited for proof
  1057 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1058 but often produces more compact proof terms with less detours;
  1059 
  1060 * Pure/Provers/classical: simplified integration with pure rule
  1061 attributes and methods; the classical "intro?/elim?/dest?"
  1062 declarations coincide with the pure ones; the "rule" method no longer
  1063 includes classically swapped intros; "intro" and "elim" methods no
  1064 longer pick rules from the context; also got rid of ML declarations
  1065 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1066 INCOMPATIBILITY;
  1067 
  1068 * Provers/classical: attribute 'swapped' produces classical inversions
  1069 of introduction rules;
  1070 
  1071 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1072 rules instead of full simplifier context; 'iff' attribute handles
  1073 conditional rules;
  1074 
  1075 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1076 
  1077 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1078 "(permissive)" option to recover old behavior;
  1079 
  1080 * HOL: 'inductive' no longer features separate (collective) attributes
  1081 for 'intros' (was found too confusing);
  1082 
  1083 * HOL: properly declared induction rules less_induct and
  1084 wf_induct_rule;
  1085 
  1086 
  1087 *** HOL ***
  1088 
  1089 * HOL: moved over to sane numeral syntax; the new policy is as
  1090 follows:
  1091 
  1092   - 0 and 1 are polymorphic constants, which are defined on any
  1093   numeric type (nat, int, real etc.);
  1094 
  1095   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1096   binary representation internally;
  1097 
  1098   - type nat has special constructor Suc, and generally prefers Suc 0
  1099   over 1::nat and Suc (Suc 0) over 2::nat;
  1100 
  1101 This change may cause significant problems of INCOMPATIBILITY; here
  1102 are some hints on converting existing sources:
  1103 
  1104   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1105   entities, so expressions involving "-" (unary or binary minus) need
  1106   to be spaced properly;
  1107 
  1108   - existing occurrences of "1" may need to be constraint "1::nat" or
  1109   even replaced by Suc 0; similar for old "2";
  1110 
  1111   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1112 
  1113   - remove all special provisions on numerals in proofs;
  1114 
  1115 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1116 representation (depends on bin_arith_simps in the default context);
  1117 
  1118 * HOL: symbolic syntax for x^2 (numeral 2);
  1119 
  1120 * HOL: the class of all HOL types is now called "type" rather than
  1121 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1122 in axclass/classes, instance/arities, and (usually rare) occurrences
  1123 in typings (of consts etc.); internally the class is called
  1124 "HOL.type", ML programs should refer to HOLogic.typeS;
  1125 
  1126 * HOL/record package improvements:
  1127   - new derived operations "fields" to build a partial record section,
  1128     "extend" to promote a fixed record to a record scheme, and
  1129     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1130     declared as simp by default;
  1131   - shared operations ("more", "fields", etc.) now need to be always
  1132     qualified) --- potential INCOMPATIBILITY;
  1133   - removed "make_scheme" operations (use "make" with "extend") --
  1134     INCOMPATIBILITY;
  1135   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1136   - provides cases/induct rules for use with corresponding Isar
  1137     methods (for concrete records, record schemes, concrete more
  1138     parts, and schematic more parts -- in that order);
  1139   - internal definitions directly based on a light-weight abstract
  1140     theory of product types over typedef rather than datatype;
  1141 
  1142 * HOL: generic code generator for generating executable ML code from
  1143 specifications; specific support for HOL constructs such as inductive
  1144 datatypes and sets, as well as recursive functions; can be invoked
  1145 via 'generate_code' theory section;
  1146 
  1147 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1148 
  1149 * HOL: consolidated and renamed several theories.  In particular:
  1150         Ord.thy has been absorbed into HOL.thy
  1151         String.thy has been absorbed into List.thy
  1152 
  1153 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1154 (beware of argument permutation!);
  1155 
  1156 * HOL: linorder_less_split superseded by linorder_cases;
  1157 
  1158 * HOL/List: "nodups" renamed to "distinct";
  1159 
  1160 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1161 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1162   - Ex_def has changed, now need to use some_eq_ex
  1163 
  1164 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1165 in this (rare) case use:
  1166 
  1167   delSWrapper "split_all_tac"
  1168   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1169 
  1170 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1171 MAY FAIL;
  1172 
  1173 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1174 Isabelle's type classes, ^ on functions and relations has too general
  1175 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1176 necessary to attach explicit type constraints;
  1177 
  1178 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1179 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1180 renamed accordingly (eg "compI" -> "rel_compI").
  1181 
  1182 * HOL: syntax translations now work properly with numerals and records
  1183 expressions;
  1184 
  1185 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1186 of "lam" -- INCOMPATIBILITY;
  1187 
  1188 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1189 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1190 renamed "Product_Type.unit";
  1191 
  1192 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1193 
  1194 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1195 the "cases" method);
  1196 
  1197 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1198 Florian Kammller);
  1199 
  1200 * HOL/IMP: updated and converted to new-style theory format; several
  1201 parts turned into readable document, with proper Isar proof texts and
  1202 some explanations (by Gerwin Klein);
  1203 
  1204 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1205 
  1206 * HOL-Hyperreal is now a logic image;
  1207 
  1208 
  1209 *** HOLCF ***
  1210 
  1211 * Isar: consts/constdefs supports mixfix syntax for continuous
  1212 operations;
  1213 
  1214 * Isar: domain package adapted to new-style theory format, e.g. see
  1215 HOLCF/ex/Dnat.thy;
  1216 
  1217 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1218 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1219 lift.induct_tac, always use UU instead of Undef;
  1220 
  1221 * HOLCF/IMP: updated and converted to new-style theory;
  1222 
  1223 
  1224 *** ZF ***
  1225 
  1226 * Isar: proper integration of logic-specific tools and packages,
  1227 including theory commands '(co)inductive', '(co)datatype',
  1228 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1229 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1230 
  1231 * theory Main no longer includes AC; for the Axiom of Choice, base
  1232 your theory on Main_ZFC;
  1233 
  1234 * the integer library now covers quotients and remainders, with many
  1235 laws relating division to addition, multiplication, etc.;
  1236 
  1237 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1238 typeless version of the formalism;
  1239 
  1240 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1241 format;
  1242 
  1243 * ZF/Induct: new directory for examples of inductive definitions,
  1244 including theory Multiset for multiset orderings; converted to
  1245 new-style theory format;
  1246 
  1247 * ZF: many new theorems about lists, ordinals, etc.;
  1248 
  1249 
  1250 *** General ***
  1251 
  1252 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1253 variable proof controls level of detail: 0 = no proofs (only oracle
  1254 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1255 also ref manual for further ML interfaces;
  1256 
  1257 * Pure/axclass: removed obsolete ML interface
  1258 goal_subclass/goal_arity;
  1259 
  1260 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1261 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1262 separate tokens, so expressions involving minus need to be spaced
  1263 properly;
  1264 
  1265 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1266 rather than "infixl" or "infixr";
  1267 
  1268 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1269 sort constraint specifications in type inference; e.g. "x::_::foo"
  1270 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1271 type variable);
  1272 
  1273 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1274 control output of nested => (types); the default behavior is
  1275 "type_brackets";
  1276 
  1277 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1278 tokens into AST constants;
  1279 
  1280 * Pure/syntax: prefer later declarations of translations and print
  1281 translation functions; potential INCOMPATIBILITY: need to reverse
  1282 multiple declarations for same syntax element constant;
  1283 
  1284 * Pure/show_hyps reset by default (in accordance to existing Isar
  1285 practice);
  1286 
  1287 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1288 addSafter;
  1289 
  1290 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1291 as well;
  1292 
  1293 * system: tested support for MacOS X; should be able to get Isabelle +
  1294 Proof General to work in a plain Terminal after installing Poly/ML
  1295 (e.g. from the Isabelle distribution area) and GNU bash alone
  1296 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1297 support requires further installations, e.g. from
  1298 http://fink.sourceforge.net/);
  1299 
  1300 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1301 
  1302 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1303 of 40 MB), cf. ML_OPTIONS;
  1304 
  1305 * system: Proof General keywords specification is now part of the
  1306 Isabelle distribution (see etc/isar-keywords.el);
  1307 
  1308 * system: support for persistent Proof General sessions (refrain from
  1309 outdating all loaded theories on startup); user may create writable
  1310 logic images like this: ``isabelle -q HOL Test'';
  1311 
  1312 * system: smart selection of Isabelle process versus Isabelle
  1313 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1314 run both "isabelle" and "Isabelle" even if file names are badly
  1315 damaged (executable inspects the case of the first letter of its own
  1316 name); added separate "isabelle-process" and "isabelle-interface";
  1317 
  1318 * system: refrain from any attempt at filtering input streams; no
  1319 longer support ``8bit'' encoding of old isabelle font, instead proper
  1320 iso-latin characters may now be used; the related isatools
  1321 "symbolinput" and "nonascii" have disappeared as well;
  1322 
  1323 * system: removed old "xterm" interface (the print modes "xterm" and
  1324 "xterm_color" are still available for direct use in a suitable
  1325 terminal);
  1326 
  1327 
  1328 
  1329 New in Isabelle99-2 (February 2001)
  1330 -----------------------------------
  1331 
  1332 *** Overview of INCOMPATIBILITIES ***
  1333 
  1334 * HOL: please note that theories in the Library and elsewhere often use the
  1335 new-style (Isar) format; to refer to their theorems in an ML script you must
  1336 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1337 
  1338 * HOL: inductive package no longer splits induction rule aggressively,
  1339 but only as far as specified by the introductions given; the old
  1340 format may be recovered via ML function complete_split_rule or attribute
  1341 'split_rule (complete)';
  1342 
  1343 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1344 gfp_Tarski to gfp_unfold;
  1345 
  1346 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1347 
  1348 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1349 relation); infix "^^" has been renamed "``"; infix "``" has been
  1350 renamed "`"; "univalent" has been renamed "single_valued";
  1351 
  1352 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1353 operation;
  1354 
  1355 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1356 
  1357 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1358 
  1359 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1360 consequence, it is no longer monotonic wrt. the local goal context
  1361 (which is now passed through the inductive cases);
  1362 
  1363 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1364 \<gg> to \<ggreater>;
  1365 
  1366 
  1367 *** Document preparation ***
  1368 
  1369 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1370 available: are "it" for near math-mode best-style output, "sl" for
  1371 slanted text style, and "tt" for plain type-writer; if no
  1372 \isabellestyle command is given, output is according to slanted
  1373 type-writer);
  1374 
  1375 * support sub/super scripts (for single symbols only), input syntax is
  1376 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1377 
  1378 * some more standard symbols; see Appendix A of the system manual for
  1379 the complete list of symbols defined in isabellesym.sty;
  1380 
  1381 * improved isabelle style files; more abstract symbol implementation
  1382 (should now use \isamath{...} and \isatext{...} in custom symbol
  1383 definitions);
  1384 
  1385 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1386 state; Note that presentation of goal states does not conform to
  1387 actual human-readable proof documents.  Please do not include goal
  1388 states into document output unless you really know what you are doing!
  1389 
  1390 * proper indentation of antiquoted output with proportional LaTeX
  1391 fonts;
  1392 
  1393 * no_document ML operator temporarily disables LaTeX document
  1394 generation;
  1395 
  1396 * isatool unsymbolize tunes sources for plain ASCII communication;
  1397 
  1398 
  1399 *** Isar ***
  1400 
  1401 * Pure: Isar now suffers initial goal statements to contain unbound
  1402 schematic variables (this does not conform to actual readable proof
  1403 documents, due to unpredictable outcome and non-compositional proof
  1404 checking); users who know what they are doing may use schematic goals
  1405 for Prolog-style synthesis of proven results;
  1406 
  1407 * Pure: assumption method (an implicit finishing) now handles actual
  1408 rules as well;
  1409 
  1410 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1411 initial goal, declare "that" only as Pure intro (only for single
  1412 steps); the "that" rule assumption may now be involved in implicit
  1413 finishing, thus ".." becomes a feasible for trivial obtains;
  1414 
  1415 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1416 instance proofs may be performed by "..";
  1417 
  1418 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1419 statements as well;
  1420 
  1421 * Pure: more robust selection of calculational rules;
  1422 
  1423 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1424 rule (as well as the assumption rule);
  1425 
  1426 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1427 lemmas, using the graph browser tool;
  1428 
  1429 * Pure: predict failure of "show" in interactive mode;
  1430 
  1431 * Pure: 'thms_containing' now takes actual terms as arguments;
  1432 
  1433 * HOL: improved method 'induct' --- now handles non-atomic goals
  1434 (potential INCOMPATIBILITY); tuned error handling;
  1435 
  1436 * HOL: cases and induct rules now provide explicit hints about the
  1437 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1438 any remaining facts are inserted into the goal verbatim;
  1439 
  1440 * HOL: local contexts (aka cases) may now contain term bindings as
  1441 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1442 the result to be shown in each case;
  1443 
  1444 * HOL: added 'recdef_tc' command;
  1445 
  1446 * isatool convert assists in eliminating legacy ML scripts;
  1447 
  1448 
  1449 *** HOL ***
  1450 
  1451 * HOL/Library: a collection of generic theories to be used together
  1452 with main HOL; the theory loader path already includes this directory
  1453 by default; the following existing theories have been moved here:
  1454 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1455 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1456 
  1457 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1458 modelling and verification task performed in Isabelle/HOL +
  1459 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1460 
  1461 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1462 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1463 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1464 'domain', this makes the theory consistent with mathematical
  1465 literature;
  1466 
  1467 * HOL basics: added overloaded operations "inverse" and "divide"
  1468 (infix "/"), syntax for generic "abs" operation, generic summation
  1469 operator \<Sum>;
  1470 
  1471 * HOL/typedef: simplified package, provide more useful rules (see also
  1472 HOL/subset.thy);
  1473 
  1474 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1475 now expressed as a proper nested rule (old-style tactic scripts may
  1476 require atomize_strip_tac to cope with non-atomic premises);
  1477 
  1478 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1479 to "split_conv" (old name still available for compatibility);
  1480 
  1481 * HOL: improved concrete syntax for strings (e.g. allows translation
  1482 rules with string literals);
  1483 
  1484 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1485  and Fleuriot's mechanization of analysis, including the transcendental
  1486  functions for the reals;
  1487 
  1488 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1489 
  1490 
  1491 *** CTT ***
  1492 
  1493 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1494 "lam" is displayed as TWO lambda-symbols
  1495 
  1496 * CTT: theory Main now available, containing everything (that is, Bool
  1497 and Arith);
  1498 
  1499 
  1500 *** General ***
  1501 
  1502 * Pure: the Simplifier has been implemented properly as a derived rule
  1503 outside of the actual kernel (at last!); the overall performance
  1504 penalty in practical applications is about 50%, while reliability of
  1505 the Isabelle inference kernel has been greatly improved;
  1506 
  1507 * print modes "brackets" and "no_brackets" control output of nested =>
  1508 (types) and ==> (props); the default behaviour is "brackets";
  1509 
  1510 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1511 as assumptions as well;
  1512 
  1513 * system: support Poly/ML 4.0;
  1514 
  1515 * system: isatool install handles KDE version 1 or 2;
  1516 
  1517 
  1518 
  1519 New in Isabelle99-1 (October 2000)
  1520 ----------------------------------
  1521 
  1522 *** Overview of INCOMPATIBILITIES ***
  1523 
  1524 * HOL: simplification of natural numbers is much changed; to partly
  1525 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1526 issue the following ML commands:
  1527 
  1528   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1529   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1530 
  1531 * HOL: simplification no longer dives into case-expressions; this is
  1532 controlled by "t.weak_case_cong" for each datatype t;
  1533 
  1534 * HOL: nat_less_induct renamed to less_induct;
  1535 
  1536 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1537 fixsome to patch .thy and .ML sources automatically;
  1538 
  1539   select_equality  -> some_equality
  1540   select_eq_Ex     -> some_eq_ex
  1541   selectI2EX       -> someI2_ex
  1542   selectI2         -> someI2
  1543   selectI          -> someI
  1544   select1_equality -> some1_equality
  1545   Eps_sym_eq       -> some_sym_eq_trivial
  1546   Eps_eq           -> some_eq_trivial
  1547 
  1548 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1549 
  1550 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1551 instead);
  1552 
  1553 * HOL: the recursion equations generated by 'recdef' are now called
  1554 f.simps instead of f.rules;
  1555 
  1556 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1557 
  1558 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1559 sometimes be needed;
  1560 
  1561 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1562 
  1563 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1564 
  1565 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1566 product is now "<*>" instead of "Times"; the lexicographic product is
  1567 now "<*lex*>" instead of "**";
  1568 
  1569 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1570 of main HOL, but was unused); better use HOL's datatype package;
  1571 
  1572 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1573 the old syntax may be recovered as follows:
  1574 
  1575   syntax (symbols)
  1576     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1577       (infixl "\\<oplus>" 100)
  1578 
  1579 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1580 
  1581 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1582 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1583 internally;
  1584 
  1585 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1586 changed from A/r to A//r;
  1587 
  1588 * ZF: new treatment of arithmetic (nat & int) may break some old
  1589 proofs;
  1590 
  1591 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1592 rulify -> rule_format, elimify -> elim_format, ...);
  1593 
  1594 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1595 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1596 should have to change intro!! to intro? only); replaced "delrule" by
  1597 "rule del";
  1598 
  1599 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1600 
  1601 * Provers: strengthened force_tac by using new first_best_tac;
  1602 
  1603 * LaTeX document preparation: several changes of isabelle.sty (see
  1604 lib/texinputs);
  1605 
  1606 
  1607 *** Document preparation ***
  1608 
  1609 * formal comments (text blocks etc.) in new-style theories may now
  1610 contain antiquotations of thm/prop/term/typ/text to be presented
  1611 according to latex print mode; concrete syntax is like this:
  1612 @{term[show_types] "f(x) = a + x"};
  1613 
  1614 * isatool mkdir provides easy setup of Isabelle session directories,
  1615 including proper document sources;
  1616 
  1617 * generated LaTeX sources are now deleted after successful run
  1618 (isatool document -c); may retain a copy somewhere else via -D option
  1619 of isatool usedir;
  1620 
  1621 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1622 style files, achieving self-contained LaTeX sources and simplifying
  1623 LaTeX debugging;
  1624 
  1625 * old-style theories now produce (crude) LaTeX output as well;
  1626 
  1627 * browser info session directories are now self-contained (may be put
  1628 on WWW server seperately); improved graphs of nested sessions; removed
  1629 graph for 'all sessions';
  1630 
  1631 * several improvements in isabelle style files; \isabellestyle{it}
  1632 produces fake math mode output; \isamarkupheader is now \section by
  1633 default; see lib/texinputs/isabelle.sty etc.;
  1634 
  1635 
  1636 *** Isar ***
  1637 
  1638 * Isar/Pure: local results and corresponding term bindings are now
  1639 subject to Hindley-Milner polymorphism (similar to ML); this
  1640 accommodates incremental type-inference very nicely;
  1641 
  1642 * Isar/Pure: new derived language element 'obtain' supports
  1643 generalized existence reasoning;
  1644 
  1645 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1646 support accumulation of results, without applying any rules yet;
  1647 useful to collect intermediate results without explicit name
  1648 references, and for use with transitivity rules with more than 2
  1649 premises;
  1650 
  1651 * Isar/Pure: scalable support for case-analysis type proofs: new
  1652 'case' language element refers to local contexts symbolically, as
  1653 produced by certain proof methods; internally, case names are attached
  1654 to theorems as "tags";
  1655 
  1656 * Isar/Pure: theory command 'hide' removes declarations from
  1657 class/type/const name spaces;
  1658 
  1659 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1660 indicate potential overloading;
  1661 
  1662 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1663 
  1664 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1665 "{a,b,c}" instead of {a,b,c};
  1666 
  1667 * Isar/Pure now provides its own version of intro/elim/dest
  1668 attributes; useful for building new logics, but beware of confusion
  1669 with the version in Provers/classical;
  1670 
  1671 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1672 case name 'antecedent';
  1673 
  1674 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1675 to the current context is now done automatically);
  1676 
  1677 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1678 for definining proof methods in ML;
  1679 
  1680 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1681 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1682 most cases, one should have to change intro!! to intro? only);
  1683 replaced "delrule" by "rule del";
  1684 
  1685 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1686 'symmetric' attribute (the latter supercedes [RS sym]);
  1687 
  1688 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1689 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1690 well (including splits);
  1691 
  1692 * Isar/Provers: Simplifier and Classical methods now support all kind
  1693 of modifiers used in the past, including 'cong', 'iff', etc.
  1694 
  1695 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1696 of Simplifier and Classical reasoner);
  1697 
  1698 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1699 now support named cases; major packages (inductive, datatype, primrec,
  1700 recdef) support case names and properly name parameters;
  1701 
  1702 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1703 monotonicity conditions are extracted to be proven at end of
  1704 calculations;
  1705 
  1706 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1707 method anyway;
  1708 
  1709 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1710 split_if split_if_asm; datatype package provides theorems foo.splits =
  1711 foo.split foo.split_asm for each datatype;
  1712 
  1713 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1714 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1715 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1716 use "(cases (simplified))" method in proper proof texts);
  1717 
  1718 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1719 
  1720 * Isar: names of theorems etc. may be natural numbers as well;
  1721 
  1722 * Isar: 'pr' command: optional arguments for goals_limit and
  1723 ProofContext.prems_limit; no longer prints theory contexts, but only
  1724 proof states;
  1725 
  1726 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1727 additional print modes to be specified; e.g. "pr(latex)" will print
  1728 proof state according to the Isabelle LaTeX style;
  1729 
  1730 * Isar: improved support for emulating tactic scripts, including proof
  1731 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1732 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1733 (for HOL datatypes);
  1734 
  1735 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1736 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1737 'proof method scripts' have to be in depth-first order;
  1738 
  1739 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1740 
  1741 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1742 should instead use individual commands for printing items
  1743 (print_commands, print_methods etc.);
  1744 
  1745 * Isar: added 'nothing' --- the empty list of theorems;
  1746 
  1747 
  1748 *** HOL ***
  1749 
  1750 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1751 corresponding virtual machine and a specification of its bytecode
  1752 verifier and a lightweight bytecode verifier, including proofs of
  1753 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1754 Cornelia Pusch (see also the homepage of project Bali at
  1755 http://isabelle.in.tum.de/Bali/);
  1756 
  1757 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1758 Clemens Ballarin;
  1759 
  1760 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1761 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1762 Rasmussen;
  1763 
  1764 * HOL/Lattice: fundamental concepts of lattice theory and order
  1765 structures, including duals, properties of bounds versus algebraic
  1766 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1767 Theorem for complete lattices etc.; may also serve as a demonstration
  1768 for abstract algebraic reasoning using axiomatic type classes, and
  1769 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1770 
  1771 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1772 von Oheimb;
  1773 
  1774 * HOL/IMPP: extension of IMP with local variables and mutually
  1775 recursive procedures, by David von Oheimb;
  1776 
  1777 * HOL/Lambda: converted into new-style theory and document;
  1778 
  1779 * HOL/ex/Multiquote: example of multiple nested quotations and
  1780 anti-quotations -- basically a generalized version of de-Bruijn
  1781 representation; very useful in avoiding lifting of operations;
  1782 
  1783 * HOL/record: added general record equality rule to simpset; fixed
  1784 select-update simplification procedure to handle extended records as
  1785 well; admit "r" as field name;
  1786 
  1787 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1788 other numeric types and also as the identity of groups, rings, etc.;
  1789 
  1790 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1791 Types nat and int belong to this axclass;
  1792 
  1793 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1794    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1795    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1796   two terms #m*u and #n*u are replaced by #(m+n)*u
  1797     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1798   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1799     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1800 
  1801 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1802 powerful prover for predicate logic but knows nothing of clasets; see
  1803 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1804 
  1805 * HOL: new version of "case_tac" subsumes both boolean case split and
  1806 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1807 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1808 
  1809 * HOL: simplification no longer dives into case-expressions: only the
  1810 selector expression is simplified, but not the remaining arms; to
  1811 enable full simplification of case-expressions for datatype t, you may
  1812 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1813 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1814 
  1815 * HOL/recdef: the recursion equations generated by 'recdef' for
  1816 function 'f' are now called f.simps instead of f.rules; if all
  1817 termination conditions are proved automatically, these simplification
  1818 rules are added to the simpset, as in primrec; rules may be named
  1819 individually as well, resulting in a separate list of theorems for
  1820 each equation;
  1821 
  1822 * HOL/While is a new theory that provides a while-combinator. It
  1823 permits the definition of tail-recursive functions without the
  1824 provision of a termination measure. The latter is necessary once the
  1825 invariant proof rule for while is applied.
  1826 
  1827 * HOL: new (overloaded) notation for the set of elements below/above
  1828 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1829 
  1830 * HOL: theorems impI, allI, ballI bound as "strip";
  1831 
  1832 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1833 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1834 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1835 
  1836 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1837 
  1838 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1839 main HOL, but was unused);
  1840 
  1841 * HOL: fewer consts declared as global (e.g. have to refer to
  1842 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1843 
  1844 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1845 in case of overlap with user translations (e.g. judgements over
  1846 tuples); (note that the underlying logical represenation is still
  1847 bogus);
  1848 
  1849 
  1850 *** ZF ***
  1851 
  1852 * ZF: simplification automatically cancels common terms in arithmetic
  1853 expressions over nat and int;
  1854 
  1855 * ZF: new treatment of nat to minimize type-checking: all operators
  1856 coerce their operands to a natural number using the function natify,
  1857 making the algebraic laws unconditional;
  1858 
  1859 * ZF: as above, for int: operators coerce their operands to an integer
  1860 using the function intify;
  1861 
  1862 * ZF: the integer library now contains many of the usual laws for the
  1863 orderings, including $<=, and monotonicity laws for $+ and $*;
  1864 
  1865 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1866 simplification;
  1867 
  1868 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1869 to the simplifier and classical reasoner simultaneously;
  1870 
  1871 
  1872 *** General ***
  1873 
  1874 * Provers: blast_tac now handles actual object-logic rules as
  1875 assumptions; note that auto_tac uses blast_tac internally as well;
  1876 
  1877 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1878 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1879 
  1880 * Provers: delrules now handles destruct rules as well (no longer need
  1881 explicit make_elim);
  1882 
  1883 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1884   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1885 use instead the strong form,
  1886   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1887 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1888 from destruct-rules;
  1889 
  1890 * Provers: Simplifier.easy_setup provides a fast path to basic
  1891 Simplifier setup for new object-logics;
  1892 
  1893 * Pure: AST translation rules no longer require constant head on LHS;
  1894 
  1895 * Pure: improved name spaces: ambiguous output is qualified; support
  1896 for hiding of names;
  1897 
  1898 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1899 XSYMBOL_HOME; no longer need to do manual configuration in most
  1900 situations;
  1901 
  1902 * system: compression of ML heaps images may now be controlled via -c
  1903 option of isabelle and isatool usedir (currently only observed by
  1904 Poly/ML);
  1905 
  1906 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1907 useful for remote X11);
  1908 
  1909 * system: provide TAGS file for Isabelle sources;
  1910 
  1911 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1912 order;
  1913 
  1914 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1915 timing flag supersedes proof_timing and Toplevel.trace;
  1916 
  1917 * ML: new combinators |>> and |>>> for incremental transformations
  1918 with secondary results (e.g. certain theory extensions):
  1919 
  1920 * ML: PureThy.add_defs gets additional argument to indicate potential
  1921 overloading (usually false);
  1922 
  1923 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1924 results;
  1925 
  1926 
  1927 
  1928 New in Isabelle99 (October 1999)
  1929 --------------------------------
  1930 
  1931 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1932 
  1933 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1934 are no longer simplified.  (This allows the simplifier to unfold recursive
  1935 functional programs.)  To restore the old behaviour, declare
  1936 
  1937     Delcongs [if_weak_cong];
  1938 
  1939 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1940 complement;
  1941 
  1942 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1943 
  1944 * HOL/datatype: mutual_induct_tac no longer exists --
  1945   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1946 
  1947 * HOL/typedef: fixed type inference for representing set; type
  1948 arguments now have to occur explicitly on the rhs as type constraints;
  1949 
  1950 * ZF: The con_defs part of an inductive definition may no longer refer
  1951 to constants declared in the same theory;
  1952 
  1953 * HOL, ZF: the function mk_cases, generated by the inductive
  1954 definition package, has lost an argument.  To simplify its result, it
  1955 uses the default simpset instead of a supplied list of theorems.
  1956 
  1957 * HOL/List: the constructors of type list are now Nil and Cons;
  1958 
  1959 * Simplifier: the type of the infix ML functions
  1960         setSSolver addSSolver setSolver addSolver
  1961 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1962 for packaging solvers. A solver is created via
  1963         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1964 where the string argument is only a comment.
  1965 
  1966 
  1967 *** Proof tools ***
  1968 
  1969 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1970 decision procedure for linear arithmetic. Currently it is used for
  1971 types `nat', `int', and `real' in HOL (see below); it can, should and
  1972 will be instantiated for other types and logics as well.
  1973 
  1974 * The simplifier now accepts rewrite rules with flexible heads, eg
  1975      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1976   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1977   matching.
  1978 
  1979 
  1980 *** General ***
  1981 
  1982 * New Isabelle/Isar subsystem provides an alternative to traditional
  1983 tactical theorem proving; together with the ProofGeneral/isar user
  1984 interface it offers an interactive environment for developing human
  1985 readable proof documents (Isar == Intelligible semi-automated
  1986 reasoning); for further information see isatool doc isar-ref,
  1987 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1988 
  1989 * improved and simplified presentation of theories: better HTML markup
  1990 (including colors), graph views in several sizes; isatool usedir now
  1991 provides a proper interface for user theories (via -P option); actual
  1992 document preparation based on (PDF)LaTeX is available as well (for
  1993 new-style theories only); see isatool doc system for more information;
  1994 
  1995 * native support for Proof General, both for classic Isabelle and
  1996 Isabelle/Isar;
  1997 
  1998 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1999 using the graph browser tool;
  2000 
  2001 * Isabelle manuals now also available as PDF;
  2002 
  2003 * theory loader rewritten from scratch (may not be fully
  2004 bug-compatible); old loadpath variable has been replaced by show_path,
  2005 add_path, del_path, reset_path functions; new operations such as
  2006 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2007 isatool doc ref);
  2008 
  2009 * improved isatool install: option -k creates KDE application icon,
  2010 option -p DIR installs standalone binaries;
  2011 
  2012 * added ML_PLATFORM setting (useful for cross-platform installations);
  2013 more robust handling of platform specific ML images for SML/NJ;
  2014 
  2015 * the settings environment is now statically scoped, i.e. it is never
  2016 created again in sub-processes invoked from isabelle, isatool, or
  2017 Isabelle;
  2018 
  2019 * path element specification '~~' refers to '$ISABELLE_HOME';
  2020 
  2021 * in locales, the "assumes" and "defines" parts may be omitted if
  2022 empty;
  2023 
  2024 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2025 long arrows);
  2026 
  2027 * new print_mode "HTML";
  2028 
  2029 * new flag show_tags controls display of tags of theorems (which are
  2030 basically just comments that may be attached by some tools);
  2031 
  2032 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2033 mode and goal output format:
  2034 
  2035 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2036 244c244
  2037 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2038 ---
  2039 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2040 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2041 181c181
  2042 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2043 ---
  2044 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2045 
  2046 * function bind_thms stores lists of theorems (cf. bind_thm);
  2047 
  2048 * new shorthand tactics ftac, eatac, datac, fatac;
  2049 
  2050 * qed (and friends) now accept "" as result name; in that case the
  2051 theorem is not stored, but proper checks and presentation of the
  2052 result still apply;
  2053 
  2054 * theorem database now also indexes constants "Trueprop", "all",
  2055 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2056 
  2057 
  2058 *** HOL ***
  2059 
  2060 ** HOL arithmetic **
  2061 
  2062 * There are now decision procedures for linear arithmetic over nat and
  2063 int:
  2064 
  2065 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2066 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2067 are treated as atomic; subformulae not involving type `nat' or `int'
  2068 are ignored; quantified subformulae are ignored unless they are
  2069 positive universal or negative existential. The tactic has to be
  2070 invoked by hand and can be a little bit slow. In particular, the
  2071 running time is exponential in the number of occurrences of `min' and
  2072 `max', and `-' on `nat'.
  2073 
  2074 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2075 (negated) (in)equalities among the premises and the conclusion into
  2076 account (i.e. no compound formulae) and does not know about `min' and
  2077 `max', and `-' on `nat'. It is fast and is used automatically by the
  2078 simplifier.
  2079 
  2080 NB: At the moment, these decision procedures do not cope with mixed
  2081 nat/int formulae where the two parts interact, such as `m < n ==>
  2082 int(m) < int(n)'.
  2083 
  2084 * HOL/Numeral provides a generic theory of numerals (encoded
  2085 efficiently as bit strings); setup for types nat/int/real is in place;
  2086 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2087 int, existing theories and proof scripts may require a few additional
  2088 type constraints;
  2089 
  2090 * integer division and remainder can now be performed on constant
  2091 arguments;
  2092 
  2093 * many properties of integer multiplication, division and remainder
  2094 are now available;
  2095 
  2096 * An interface to the Stanford Validity Checker (SVC) is available through the
  2097 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2098 are proved automatically.  SVC must be installed separately, and its results
  2099 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2100 invocation of the underlying oracle).  For SVC see
  2101   http://verify.stanford.edu/SVC
  2102 
  2103 * IsaMakefile: the HOL-Real target now builds an actual image;
  2104 
  2105 
  2106 ** HOL misc **
  2107 
  2108 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2109 (in Isabelle/Isar) -- by Gertrud Bauer;
  2110 
  2111 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2112 analysis for assembly languages with subtypes;
  2113 
  2114 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2115 -- avoids syntactic ambiguities and treats state, transition, and
  2116 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2117 changed syntax and (many) tactics;
  2118 
  2119 * HOL/inductive: Now also handles more general introduction rules such
  2120   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2121   theorems are now maintained within the theory (maintained via the
  2122   "mono" attribute);
  2123 
  2124 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2125   (using function types) such as
  2126 
  2127   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2128 
  2129 * HOL/record: record_simproc (part of the default simpset) takes care
  2130 of selectors applied to updated records; record_split_tac is no longer
  2131 part of the default claset; update_defs may now be removed from the
  2132 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2133 
  2134   claset_ref () := claset() addSWrapper record_split_wrapper;
  2135   Delsimprocs [record_simproc]
  2136 
  2137 * HOL/typedef: fixed type inference for representing set; type
  2138 arguments now have to occur explicitly on the rhs as type constraints;
  2139 
  2140 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2141 names rather than an ML expression;
  2142 
  2143 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2144 supplied later.  Program schemes can be defined, such as
  2145     "While B C s = (if B s then While B C (C s) else s)"
  2146 where the well-founded relation can be chosen after B and C have been given.
  2147 
  2148 * HOL/List: the constructors of type list are now Nil and Cons;
  2149 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2150 course, ML tools referring to List.list.op # etc. have to be adapted;
  2151 
  2152 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2153 disabled by default; run isabelle with option -m HOL to get back to
  2154 the original Gordon/HOL-style output;
  2155 
  2156 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2157 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2158 
  2159 * HOL basic syntax simplified (more orthogonal): all variants of
  2160 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2161 Eps operator is provided as well: "SOME x. P[x]";
  2162 
  2163 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2164 
  2165 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2166 thus available for user theories;
  2167 
  2168 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2169 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2170 time;
  2171 
  2172 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2173 several times and then mp;
  2174 
  2175 
  2176 *** LK ***
  2177 
  2178 * the notation <<...>> is now available as a notation for sequences of
  2179 formulas;
  2180 
  2181 * the simplifier is now installed
  2182 
  2183 * the axiom system has been generalized (thanks to Soren Heilmann)
  2184 
  2185 * the classical reasoner now has a default rule database
  2186 
  2187 
  2188 *** ZF ***
  2189 
  2190 * new primrec section allows primitive recursive functions to be given
  2191 directly (as in HOL) over datatypes and the natural numbers;
  2192 
  2193 * new tactics induct_tac and exhaust_tac for induction (or case
  2194 analysis) over datatypes and the natural numbers;
  2195 
  2196 * the datatype declaration of type T now defines the recursor T_rec;
  2197 
  2198 * simplification automatically does freeness reasoning for datatype
  2199 constructors;
  2200 
  2201 * automatic type-inference, with AddTCs command to insert new
  2202 type-checking rules;
  2203 
  2204 * datatype introduction rules are now added as Safe Introduction rules
  2205 to the claset;
  2206 
  2207 * the syntax "if P then x else y" is now available in addition to
  2208 if(P,x,y);
  2209 
  2210 
  2211 *** Internal programming interfaces ***
  2212 
  2213 * tuned simplifier trace output; new flag debug_simp;
  2214 
  2215 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2216 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2217 
  2218 * AxClass.axclass_tac lost the theory argument;
  2219 
  2220 * tuned current_goals_markers semantics: begin / end goal avoids
  2221 printing empty lines;
  2222 
  2223 * removed prs and prs_fn hook, which was broken because it did not
  2224 include \n in its semantics, forcing writeln to add one
  2225 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2226 string -> unit if you really want to output text without newline;
  2227 
  2228 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2229 plain output, interface builders may have to enable 'isabelle_font'
  2230 mode to get Isabelle font glyphs as before;
  2231 
  2232 * refined token_translation interface; INCOMPATIBILITY: output length
  2233 now of type real instead of int;
  2234 
  2235 * theory loader actions may be traced via new ThyInfo.add_hook
  2236 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2237 your own database of information attached to *whole* theories -- as
  2238 opposed to intra-theory data slots offered via TheoryDataFun;
  2239 
  2240 * proper handling of dangling sort hypotheses (at last!);
  2241 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2242 extra sort hypotheses that can be witnessed from the type signature;
  2243 the force_strip_shyps flag is gone, any remaining shyps are simply
  2244 left in the theorem (with a warning issued by strip_shyps_warning);
  2245 
  2246 
  2247 
  2248 New in Isabelle98-1 (October 1998)
  2249 ----------------------------------
  2250 
  2251 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2252 
  2253 * several changes of automated proof tools;
  2254 
  2255 * HOL: major changes to the inductive and datatype packages, including
  2256 some minor incompatibilities of theory syntax;
  2257 
  2258 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2259 called `inj_on';
  2260 
  2261 * HOL: removed duplicate thms in Arith:
  2262   less_imp_add_less  should be replaced by  trans_less_add1
  2263   le_imp_add_le      should be replaced by  trans_le_add1
  2264 
  2265 * HOL: unary minus is now overloaded (new type constraints may be
  2266 required);
  2267 
  2268 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2269 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2270 now taken as an integer constant.
  2271 
  2272 * Pure: ML function 'theory_of' renamed to 'theory';
  2273 
  2274 
  2275 *** Proof tools ***
  2276 
  2277 * Simplifier:
  2278   1. Asm_full_simp_tac is now more aggressive.
  2279      1. It will sometimes reorient premises if that increases their power to
  2280         simplify.
  2281      2. It does no longer proceed strictly from left to right but may also
  2282         rotate premises to achieve further simplification.
  2283      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2284      old Asm_full_simp_tac in that it does not rotate premises.
  2285   2. The simplifier now knows a little bit about nat-arithmetic.
  2286 
  2287 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2288 allows for selected deletion of wrappers, by introduction of names for
  2289 wrapper functionals.  This implies that addbefore, addSbefore,
  2290 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2291 and that adding two tactics with the same name overwrites the first
  2292 one (emitting a warning).
  2293   type wrapper = (int -> tactic) -> (int -> tactic)
  2294   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2295   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2296   delWrapper, delSWrapper: claset *  string            -> claset
  2297   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2298 
  2299 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2300 semantics; addbefore now affects only the unsafe part of step_tac
  2301 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2302 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2303 by Force_tac;
  2304 
  2305 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2306 compWrapper; added safe wrapper (and access functions for it);
  2307 
  2308 * HOL/split_all_tac is now much faster and fails if there is nothing
  2309 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2310 and the names of the automatically generated variables have changed.
  2311 split_all_tac has moved within claset() from unsafe wrappers to safe
  2312 wrappers, which means that !!-bound variables are split much more
  2313 aggressively, and safe_tac and clarify_tac now split such variables.
  2314 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2315 Note: the same holds for record_split_tac, which does the job of
  2316 split_all_tac for record fields.
  2317 
  2318 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2319 permanently to the default simpset using Addsplits just like
  2320 Addsimps. They can be removed via Delsplits just like
  2321 Delsimps. Lower-case versions are also available.
  2322 
  2323 * HOL/Simplifier: The rule split_if is now part of the default
  2324 simpset. This means that the simplifier will eliminate all occurrences
  2325 of if-then-else in the conclusion of a goal. To prevent this, you can
  2326 either remove split_if completely from the default simpset by
  2327 `Delsplits [split_if]' or remove it in a specific call of the
  2328 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2329 other case splitting rules to/from the default simpset: every datatype
  2330 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2331 t is the name of the datatype).
  2332 
  2333 * Classical reasoner / Simplifier combination: new force_tac (and
  2334 derivatives Force_tac, force) combines rewriting and classical
  2335 reasoning (and whatever other tools) similarly to auto_tac, but is
  2336 aimed to solve the given subgoal completely.
  2337 
  2338 
  2339 *** General ***
  2340 
  2341 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2342 and `goalw': the theory is no longer needed as an explicit argument -
  2343 the current theory context is used; assumptions are no longer returned
  2344 at the ML-level unless one of them starts with ==> or !!; it is
  2345 recommended to convert to these new commands using isatool fixgoal
  2346 (backup your sources first!);
  2347 
  2348 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2349 the current theory context, and 'theory' to lookup stored theories;
  2350 
  2351 * new theory section 'locale' for declaring constants, assumptions and
  2352 definitions that have local scope;
  2353 
  2354 * new theory section 'nonterminals' for purely syntactic types;
  2355 
  2356 * new theory section 'setup' for generic ML setup functions
  2357 (e.g. package initialization);
  2358 
  2359 * the distribution now includes Isabelle icons: see
  2360 lib/logo/isabelle-{small,tiny}.xpm;
  2361 
  2362 * isatool install - install binaries with absolute references to
  2363 ISABELLE_HOME/bin;
  2364 
  2365 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2366 
  2367 * print mode 'emacs' reserved for Isamode;
  2368 
  2369 * support multiple print (ast) translations per constant name;
  2370 
  2371 * theorems involving oracles are now printed with a suffixed [!];
  2372 
  2373 
  2374 *** HOL ***
  2375 
  2376 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2377 
  2378 * HOL/inductive package reorganized and improved: now supports mutual
  2379 definitions such as
  2380 
  2381   inductive EVEN ODD
  2382     intrs
  2383       null "0 : EVEN"
  2384       oddI "n : EVEN ==> Suc n : ODD"
  2385       evenI "n : ODD ==> Suc n : EVEN"
  2386 
  2387 new theorem list "elims" contains an elimination rule for each of the
  2388 recursive sets; inductive definitions now handle disjunctive premises
  2389 correctly (also ZF);
  2390 
  2391 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2392 "mutual_induct" no longer exists - the induction rule is always
  2393 contained in "induct";
  2394 
  2395 
  2396 * HOL/datatype package re-implemented and greatly improved: now
  2397 supports mutually recursive datatypes such as
  2398 
  2399   datatype
  2400     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2401             | SUM ('a aexp) ('a aexp)
  2402             | DIFF ('a aexp) ('a aexp)
  2403             | NUM 'a
  2404   and
  2405     'a bexp = LESS ('a aexp) ('a aexp)
  2406             | AND ('a bexp) ('a bexp)
  2407             | OR ('a bexp) ('a bexp)
  2408 
  2409 as well as indirectly recursive datatypes such as
  2410 
  2411   datatype
  2412     ('a, 'b) term = Var 'a
  2413                   | App 'b ((('a, 'b) term) list)
  2414 
  2415 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2416 induction on mutually / indirectly recursive datatypes.
  2417 
  2418 Primrec equations are now stored in theory and can be accessed via
  2419 <function_name>.simps.
  2420 
  2421 INCOMPATIBILITIES:
  2422 
  2423   - Theories using datatypes must now have theory Datatype as an
  2424     ancestor.
  2425   - The specific <typename>.induct_tac no longer exists - use the
  2426     generic induct_tac instead.
  2427   - natE has been renamed to nat.exhaust - use exhaust_tac
  2428     instead of res_inst_tac ... natE. Note that the variable
  2429     names in nat.exhaust differ from the names in natE, this
  2430     may cause some "fragile" proofs to fail.
  2431   - The theorems split_<typename>_case and split_<typename>_case_asm
  2432     have been renamed to <typename>.split and <typename>.split_asm.
  2433   - Since default sorts of type variables are now handled correctly,
  2434     some datatype definitions may have to be annotated with explicit
  2435     sort constraints.
  2436   - Primrec definitions no longer require function name and type
  2437     of recursive argument.
  2438 
  2439 Consider using isatool fixdatatype to adapt your theories and proof
  2440 scripts to the new package (backup your sources first!).
  2441 
  2442 
  2443 * HOL/record package: considerably improved implementation; now
  2444 includes concrete syntax for record types, terms, updates; theorems
  2445 for surjective pairing and splitting !!-bound record variables; proof
  2446 support is as follows:
  2447 
  2448   1) standard conversions (selectors or updates applied to record
  2449 constructor terms) are part of the standard simpset;
  2450 
  2451   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2452 made part of standard simpset and claset via addIffs;
  2453 
  2454   3) a tactic for record field splitting (record_split_tac) is part of
  2455 the standard claset (addSWrapper);
  2456 
  2457 To get a better idea about these rules you may retrieve them via
  2458 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2459 the name of your record type.
  2460 
  2461 The split tactic 3) conceptually simplifies by the following rule:
  2462 
  2463   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2464 
  2465 Thus any record variable that is bound by meta-all will automatically
  2466 blow up into some record constructor term, consequently the
  2467 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2468 solve record problems automatically.
  2469 
  2470 
  2471 * reorganized the main HOL image: HOL/Integ and String loaded by
  2472 default; theory Main includes everything;
  2473 
  2474 * automatic simplification of integer sums and comparisons, using cancellation;
  2475 
  2476 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2477 
  2478 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2479 
  2480 * many new identities for unions, intersections, set difference, etc.;
  2481 
  2482 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2483 called split_if, split_split, split_sum_case and split_nat_case (to go
  2484 with add/delsplits);
  2485 
  2486 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2487 (?x::unit) = (); this is made part of the default simpset, which COULD
  2488 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2489 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2490 unit_abs_eta_conv is added in order to counter the effect of
  2491 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2492 %u.f();
  2493 
  2494 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2495 makes more sense);
  2496 
  2497 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2498   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2499   disjointness reasoning but breaking a few old proofs.
  2500 
  2501 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2502 to 'converse' from 'inverse' (for compatibility with ZF and some
  2503 literature);
  2504 
  2505 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2506 the well-founded relation;
  2507 
  2508 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2509     Compl A.  The "Compl" syntax remains available as input syntax for this
  2510     release ONLY.
  2511 
  2512 * HOL/Update: new theory of function updates:
  2513     f(a:=b) == %x. if x=a then b else f x
  2514 may also be iterated as in f(a:=b,c:=d,...);
  2515 
  2516 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2517 
  2518 * HOL/List:
  2519   - new function list_update written xs[i:=v] that updates the i-th
  2520     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2521   - new function `upt' written [i..j(] which generates the list
  2522     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2523     bound write [i..j], which is a shorthand for [i..j+1(].
  2524   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2525 
  2526 * HOL/Arith:
  2527   - removed 'pred' (predecessor) function;
  2528   - generalized some theorems about n-1;
  2529   - many new laws about "div" and "mod";
  2530   - new laws about greatest common divisors (see theory ex/Primes);
  2531 
  2532 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2533 instead of "inverse";
  2534 
  2535 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2536   of the multiset ordering;
  2537 
  2538 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2539   (not included by default);
  2540 
  2541 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2542 
  2543 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2544   programs, i.e. different program variables may have different types.
  2545 
  2546 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2547   [previously, this check worked only if the rewrite rule was unconditional]
  2548   Now rew can involve either definitions or equalities (either == or =).
  2549 
  2550 
  2551 *** ZF ***
  2552 
  2553 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2554   only the theorems proved on ZF.ML;
  2555 
  2556 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2557   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2558   disjointness reasoning but breaking a few old proofs.
  2559 
  2560 * ZF/Update: new theory of function updates
  2561     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2562   may also be iterated as in f(a:=b,c:=d,...);
  2563 
  2564 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2565 
  2566 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2567   [previously, this check worked only if the rewrite rule was unconditional]
  2568   Now rew can involve either definitions or equalities (either == or =).
  2569 
  2570 * case_tac provided for compatibility with HOL
  2571     (like the old excluded_middle_tac, but with subgoals swapped)
  2572 
  2573 
  2574 *** Internal programming interfaces ***
  2575 
  2576 * Pure: several new basic modules made available for general use, see
  2577 also src/Pure/README;
  2578 
  2579 * improved the theory data mechanism to support encapsulation (data
  2580 kind name replaced by private Object.kind, acting as authorization
  2581 key); new type-safe user interface via functor TheoryDataFun; generic
  2582 print_data function becomes basically useless;
  2583 
  2584 * removed global_names compatibility flag -- all theory declarations
  2585 are qualified by default;
  2586 
  2587 * module Pure/Syntax now offers quote / antiquote translation
  2588 functions (useful for Hoare logic etc. with implicit dependencies);
  2589 see HOL/ex/Antiquote for an example use;
  2590 
  2591 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2592 cterm -> thm;
  2593 
  2594 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2595 subgoal;
  2596 
  2597 * Display.print_goals function moved to Locale.print_goals;
  2598 
  2599 * standard print function for goals supports current_goals_markers
  2600 variable for marking begin of proof, end of proof, start of goal; the
  2601 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2602 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2603 for example;
  2604 
  2605 
  2606 
  2607 New in Isabelle98 (January 1998)
  2608 --------------------------------
  2609 
  2610 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2611 
  2612 * changed lexical syntax of terms / types: dots made part of long
  2613 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2614 
  2615 * simpset (and claset) reference variable replaced by functions
  2616 simpset / simpset_ref;
  2617 
  2618 * no longer supports theory aliases (via merge) and non-trivial
  2619 implicit merge of thms' signatures;
  2620 
  2621 * most internal names of constants changed due to qualified names;
  2622 
  2623 * changed Pure/Sequence interface (see Pure/seq.ML);
  2624 
  2625 
  2626 *** General Changes ***
  2627 
  2628 * hierachically structured name spaces (for consts, types, axms, thms
  2629 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2630 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2631 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2632 long_names for fully qualified output names; NOTE: ML programs
  2633 (special tactics, packages etc.) referring to internal names may have
  2634 to be adapted to cope with fully qualified names; in case of severe
  2635 backward campatibility problems try setting 'global_names' at compile
  2636 time to have enrything declared within a flat name space; one may also
  2637 fine tune name declarations in theories via the 'global' and 'local'
  2638 section;
  2639 
  2640 * reimplemented the implicit simpset and claset using the new anytype
  2641 data filed in signatures; references simpset:simpset ref etc. are
  2642 replaced by functions simpset:unit->simpset and
  2643 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2644 to patch your ML files accordingly;
  2645 
  2646 * HTML output now includes theory graph data for display with Java
  2647 applet or isatool browser; data generated automatically via isatool
  2648 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2649 
  2650 * defs may now be conditional; improved rewrite_goals_tac to handle
  2651 conditional equations;
  2652 
  2653 * defs now admits additional type arguments, using TYPE('a) syntax;
  2654 
  2655 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2656 creates a new theory node; implicit merge of thms' signatures is
  2657 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2658 transfer:theory->thm->thm in (rare) cases;
  2659 
  2660 * improved handling of draft signatures / theories; draft thms (and
  2661 ctyps, cterms) are automatically promoted to real ones;
  2662 
  2663 * slightly changed interfaces for oracles: admit many per theory, named
  2664 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2665 
  2666 * print_goals: optional output of const types (set show_consts and
  2667 show_types);
  2668 
  2669 * improved output of warnings (###) and errors (***);
  2670 
  2671 * subgoal_tac displays a warning if the new subgoal has type variables;
  2672 
  2673 * removed old README and Makefiles;
  2674 
  2675 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2676 
  2677 * removed obsolete init_pps and init_database;
  2678 
  2679 * deleted the obsolete tactical STATE, which was declared by
  2680     fun STATE tacfun st = tacfun st st;
  2681 
  2682 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2683 (which abbreviates $HOME);
  2684 
  2685 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2686 use isatool fixseq to adapt your ML programs (this works for fully
  2687 qualified references to the Sequence structure only!);
  2688 
  2689 * use_thy no longer requires writable current directory; it always
  2690 reloads .ML *and* .thy file, if either one is out of date;
  2691 
  2692 
  2693 *** Classical Reasoner ***
  2694 
  2695 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2696 tactics that use classical reasoning to simplify a subgoal without
  2697 splitting it into several subgoals;
  2698 
  2699 * Safe_tac: like safe_tac but uses the default claset;
  2700 
  2701 
  2702 *** Simplifier ***
  2703 
  2704 * added simplification meta rules:
  2705     (asm_)(full_)simplify: simpset -> thm -> thm;
  2706 
  2707 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2708 logics (again);
  2709 
  2710 * added prems argument to simplification procedures;
  2711 
  2712 * HOL, FOL, ZF: added infix function `addsplits':
  2713   instead of `<simpset> setloop (split_tac <thms>)'
  2714   you can simply write `<simpset> addsplits <thms>'
  2715 
  2716 
  2717 *** Syntax ***
  2718 
  2719 * TYPE('a) syntax for type reflection terms;
  2720 
  2721 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2722 
  2723 * pretty printer: changed order of mixfix annotation preference (again!);
  2724 
  2725 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2726 
  2727 
  2728 *** HOL ***
  2729 
  2730 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2731   with `addloop' of the simplifier to faciliate case splitting in premises.
  2732 
  2733 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2734 
  2735 * HOL/Auth: new protocol proofs including some for the Internet
  2736   protocol TLS;
  2737 
  2738 * HOL/Map: new theory of `maps' a la VDM;
  2739 
  2740 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2741 cancelling out common nat summands from =, <, <= (in)equalities, or
  2742 differences; simplification procedures nat_cancel_factor for
  2743 cancelling common factor from =, <, <= (in)equalities over natural
  2744 sums; nat_cancel contains both kinds of procedures, it is installed by
  2745 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2746 
  2747 * HOL/simplifier: terms of the form
  2748   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2749   are rewritten to
  2750   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2751   and those of the form
  2752   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2753   are rewritten to
  2754   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2755 
  2756 * HOL/datatype
  2757   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2758 
  2759   P(t_case f1 ... fn x) =
  2760      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2761         ...
  2762        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2763      )
  2764 
  2765   and a theorem `split_t_case_asm' of the form
  2766 
  2767   P(t_case f1 ... fn x) =
  2768     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2769         ...
  2770        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2771      )
  2772   which can be added to a simpset via `addsplits'. The existing theorems
  2773   expand_list_case and expand_option_case have been renamed to
  2774   split_list_case and split_option_case.
  2775 
  2776 * HOL/Arithmetic:
  2777   - `pred n' is automatically converted to `n-1'.
  2778     Users are strongly encouraged not to use `pred' any longer,
  2779     because it will disappear altogether at some point.
  2780   - Users are strongly encouraged to write "0 < n" rather than
  2781     "n ~= 0". Theorems and proof tools have been modified towards this
  2782     `standard'.
  2783 
  2784 * HOL/Lists:
  2785   the function "set_of_list" has been renamed "set" (and its theorems too);
  2786   the function "nth" now takes its arguments in the reverse order and
  2787   has acquired the infix notation "!" as in "xs!n".
  2788 
  2789 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2790 
  2791 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2792   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2793 
  2794 * HOL/record: extensible records with schematic structural subtyping
  2795 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2796 still lacks various theorems and concrete record syntax;
  2797 
  2798 
  2799 *** HOLCF ***
  2800 
  2801 * removed "axioms" and "generated by" sections;
  2802 
  2803 * replaced "ops" section by extended "consts" section, which is capable of
  2804   handling the continuous function space "->" directly;
  2805 
  2806 * domain package:
  2807   . proves theorems immediately and stores them in the theory,
  2808   . creates hierachical name space,
  2809   . now uses normal mixfix annotations (instead of cinfix...),
  2810   . minor changes to some names and values (for consistency),
  2811   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2812   . separator between mutual domain defs: changed "," to "and",
  2813   . improved handling of sort constraints;  now they have to
  2814     appear on the left-hand side of the equations only;
  2815 
  2816 * fixed LAM <x,y,zs>.b syntax;
  2817 
  2818 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2819 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2820 
  2821 
  2822 *** FOL and ZF ***
  2823 
  2824 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2825   with `addloop' of the simplifier to faciliate case splitting in premises.
  2826 
  2827 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2828 in HOL, they strip ALL and --> from proved theorems;
  2829 
  2830 
  2831 
  2832 New in Isabelle94-8 (May 1997)
  2833 ------------------------------
  2834 
  2835 *** General Changes ***
  2836 
  2837 * new utilities to build / run / maintain Isabelle etc. (in parts
  2838 still somewhat experimental); old Makefiles etc. still functional;
  2839 
  2840 * new 'Isabelle System Manual';
  2841 
  2842 * INSTALL text, together with ./configure and ./build scripts;
  2843 
  2844 * reimplemented type inference for greater efficiency, better error
  2845 messages and clean internal interface;
  2846 
  2847 * prlim command for dealing with lots of subgoals (an easier way of
  2848 setting goals_limit);
  2849 
  2850 
  2851 *** Syntax ***
  2852 
  2853 * supports alternative (named) syntax tables (parser and pretty
  2854 printer); internal interface is provided by add_modesyntax(_i);
  2855 
  2856 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2857 be used in conjunction with the Isabelle symbol font; uses the
  2858 "symbols" syntax table;
  2859 
  2860 * added token_translation interface (may translate name tokens in
  2861 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2862 the current print_mode); IMPORTANT: user print translation functions
  2863 are responsible for marking newly introduced bounds
  2864 (Syntax.mark_boundT);
  2865 
  2866 * token translations for modes "xterm" and "xterm_color" that display
  2867 names in bold, underline etc. or colors (which requires a color
  2868 version of xterm);
  2869 
  2870 * infixes may now be declared with names independent of their syntax;
  2871 
  2872 * added typed_print_translation (like print_translation, but may
  2873 access type of constant);
  2874 
  2875 
  2876 *** Classical Reasoner ***
  2877 
  2878 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2879 some limitations.  Blast_tac...
  2880   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2881   + ignores elimination rules that don't have the correct format
  2882         (the conclusion MUST be a formula variable)
  2883   + ignores types, which can make HOL proofs fail
  2884   + rules must not require higher-order unification, e.g. apply_type in ZF
  2885     [message "Function Var's argument not a bound variable" relates to this]
  2886   + its proof strategy is more general but can actually be slower
  2887 
  2888 * substitution with equality assumptions no longer permutes other
  2889 assumptions;
  2890 
  2891 * minor changes in semantics of addafter (now called addaltern); renamed
  2892 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2893 (and access functions for it);
  2894 
  2895 * improved combination of classical reasoner and simplifier:
  2896   + functions for handling clasimpsets
  2897   + improvement of addss: now the simplifier is called _after_ the
  2898     safe steps.
  2899   + safe variant of addss called addSss: uses safe simplifications
  2900     _during_ the safe steps. It is more complete as it allows multiple
  2901     instantiations of unknowns (e.g. with slow_tac).
  2902 
  2903 *** Simplifier ***
  2904 
  2905 * added interface for simplification procedures (functions that
  2906 produce *proven* rewrite rules on the fly, depending on current
  2907 redex);
  2908 
  2909 * ordering on terms as parameter (used for ordered rewriting);
  2910 
  2911 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2912 
  2913 * the solver is now split into a safe and an unsafe part.
  2914 This should be invisible for the normal user, except that the
  2915 functions setsolver and addsolver have been renamed to setSolver and
  2916 addSolver; added safe_asm_full_simp_tac;
  2917 
  2918 
  2919 *** HOL ***
  2920 
  2921 * a generic induction tactic `induct_tac' which works for all datatypes and
  2922 also for type `nat';
  2923 
  2924 * a generic case distinction tactic `exhaust_tac' which works for all
  2925 datatypes and also for type `nat';
  2926 
  2927 * each datatype comes with a function `size';
  2928 
  2929 * patterns in case expressions allow tuple patterns as arguments to
  2930 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2931 
  2932 * primrec now also works with type nat;
  2933 
  2934 * recdef: a new declaration form, allows general recursive functions to be
  2935 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2936 
  2937 * the constant for negation has been renamed from "not" to "Not" to
  2938 harmonize with FOL, ZF, LK, etc.;
  2939 
  2940 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2941 infinite lists;
  2942 
  2943 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2944 
  2945 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2946 problems in commutative rings, using axiomatic type classes for + and *;
  2947 
  2948 * more examples in HOL/MiniML and HOL/Auth;
  2949 
  2950 * more default rewrite rules for quantifiers, union/intersection;
  2951 
  2952 * a new constant `arbitrary == @x.False';
  2953 
  2954 * HOLCF/IOA replaces old HOL/IOA;
  2955 
  2956 * HOLCF changes: derived all rules and arities
  2957   + axiomatic type classes instead of classes
  2958   + typedef instead of faking type definitions
  2959   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2960   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2961   + eliminated the types void, one, tr
  2962   + use unit lift and bool lift (with translations) instead of one and tr
  2963   + eliminated blift from Lift3.thy (use Def instead of blift)
  2964   all eliminated rules are derived as theorems --> no visible changes ;
  2965 
  2966 
  2967 *** ZF ***
  2968 
  2969 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2970 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2971 as ZF_cs addSIs [equalityI];
  2972 
  2973 
  2974 
  2975 New in Isabelle94-7 (November 96)
  2976 ---------------------------------
  2977 
  2978 * allowing negative levels (as offsets) in prlev and choplev;
  2979 
  2980 * super-linear speedup for large simplifications;
  2981 
  2982 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2983 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2984 FAIL); can suppress it using the command Delsimps (ex_simps @
  2985 all_simps); De Morgan laws are also now included, by default;
  2986 
  2987 * improved printing of ==>  :  ~:
  2988 
  2989 * new object-logic "Sequents" adds linear logic, while replacing LK
  2990 and Modal (thanks to Sara Kalvala);
  2991 
  2992 * HOL/Auth: correctness proofs for authentication protocols;
  2993 
  2994 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2995 examples on HOL/Auth);
  2996 
  2997 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2998 the rewriter and classical reasoner simultaneously;
  2999 
  3000 * function uresult no longer returns theorems in "standard" format;
  3001 regain previous version by: val uresult = standard o uresult;
  3002 
  3003 
  3004 
  3005 New in Isabelle94-6
  3006 -------------------
  3007 
  3008 * oracles -- these establish an interface between Isabelle and trusted
  3009 external reasoners, which may deliver results as theorems;
  3010 
  3011 * proof objects (in particular record all uses of oracles);
  3012 
  3013 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3014 
  3015 * "constdefs" section in theory files;
  3016 
  3017 * "primrec" section (HOL) no longer requires names;
  3018 
  3019 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3020 
  3021 
  3022 
  3023 New in Isabelle94-5
  3024 -------------------
  3025 
  3026 * reduced space requirements;
  3027 
  3028 * automatic HTML generation from theories;
  3029 
  3030 * theory files no longer require "..." (quotes) around most types;
  3031 
  3032 * new examples, including two proofs of the Church-Rosser theorem;
  3033 
  3034 * non-curried (1994) version of HOL is no longer distributed;
  3035 
  3036 
  3037 
  3038 New in Isabelle94-4
  3039 -------------------
  3040 
  3041 * greatly reduced space requirements;
  3042 
  3043 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3044 
  3045 * searchable theorem database (see the section "Retrieving theorems" on
  3046 page 8 of the Reference Manual);
  3047 
  3048 * new examples, including Grabczewski's monumental case study of the
  3049 Axiom of Choice;
  3050 
  3051 * The previous version of HOL renamed to Old_HOL;
  3052 
  3053 * The new version of HOL (previously called CHOL) uses a curried syntax
  3054 for functions.  Application looks like f a b instead of f(a,b);
  3055 
  3056 * Mutually recursive inductive definitions finally work in HOL;
  3057 
  3058 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3059 translates to the operator "split";
  3060 
  3061 
  3062 
  3063 New in Isabelle94-3
  3064 -------------------
  3065 
  3066 * new infix operator, addss, allowing the classical reasoner to
  3067 perform simplification at each step of its search.  Example:
  3068         fast_tac (cs addss ss)
  3069 
  3070 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3071 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3072 look like (a,b) instead of <a,b>;
  3073 
  3074 * PLEASE NOTE: CHOL will eventually replace HOL!
  3075 
  3076 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3077 It translates to the operator "split".  A new theory of integers is available;
  3078 
  3079 * In ZF, integer numerals now denote two's-complement binary integers.
  3080 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3081 
  3082 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3083 of the Axiom of Choice;
  3084 
  3085 
  3086 
  3087 New in Isabelle94-2
  3088 -------------------
  3089 
  3090 * Significantly faster resolution;
  3091 
  3092 * the different sections in a .thy file can now be mixed and repeated
  3093 freely;
  3094 
  3095 * Database of theorems for FOL, HOL and ZF.  New
  3096 commands including qed, qed_goal and bind_thm store theorems in the database.
  3097 
  3098 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3099 a given theory (thms_of), or find out what theory a theorem was proved in
  3100 (theory_of_thm);
  3101 
  3102 * Bugs fixed in the inductive definition and datatype packages;
  3103 
  3104 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3105 and HOL_dup_cs obsolete;
  3106 
  3107 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3108 have been removed;
  3109 
  3110 * Simpler definition of function space in ZF;
  3111 
  3112 * new results about cardinal and ordinal arithmetic in ZF;
  3113 
  3114 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3115 types;
  3116 
  3117 
  3118 $Id$