NEWS

added translations for SORT_CONSTRAINT
tuned;

Isabelle NEWS -- history user-relevant changes
==============================================

New in this Isabelle version
----------------------------

*** General ***

* Simplified main Isabelle executables, with less surprises on
case-insensitive file-systems (such as Mac OS).

  - The main Isabelle tool wrapper is now called "isabelle" instead of
    "isatool."

  - The former "isabelle" alias for "isabelle-process" has been
    removed (should rarely occur to regular users).

  - The "Isabelle" alias for "isabelle-interface" has been removed.

Within scripts and make files, the Isabelle environment variables
ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
respectively.  (The latter are still available as legacy feature.)

Also note that user interfaces are now better wrapped as regular
Isabelle tools instead of using the special isabelle-interface wrapper
(which can be confusing if the interface is uninstalled or changed
otherwise).  See "isabelle tty" and "isabelle emacs" for contemporary
examples.

INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
purge installed copies of Isabelle executables and re-run "isabelle
install -p ...", or use symlinks.

* The Isabelle System Manual (system) has been updated, with formally
checked references as hyperlinks.

* Generalized Isar history, with support for linear undo, direct state
addressing etc.

* Recovered hiding of consts, which was accidentally broken in
Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
makes c inaccessible; consider using ``hide (open) const c'' instead.

* Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
interface instead.


*** Pure ***

* Changed defaults for unify configuration options:

  unify_trace_bound = 50 (formerly 25)
  unify_search_bound = 60 (formerly 30)

* Different bookkeeping for code equations:
  a) On theory merge, the last set of code equations for a particular constant
     is taken (in accordance with the policy applied by other parts of the
     code generator framework).
  b) Code equations stemming from explicit declarations (e.g. code attribute)
     gain priority over default code equations stemming from definition, primrec,
     fun etc.
  INCOMPATIBILITY.

* Global versions of theorems stemming from classes do not carry
a parameter prefix any longer.  INCOMPATIBILITY.

* Dropped "locale (open)".  INCOMPATBILITY.

* Interpretation commands no longer attempt to simplify goal.
INCOMPATIBILITY: in rare situations the generated goal differs.  Use
methods intro_locales and unfold_locales to clarify.

* Interpretation commands no longer accept interpretation attributes.
INCOMPATBILITY.

* Command 'instance': attached definitions no longer accepted.
INCOMPATIBILITY, use proper 'instantiation' target.

* Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.

* The 'axiomatization' command now only works within a global theory
context.  INCOMPATIBILITY.


*** Document preparation ***

* Antiquotation @{lemma} now imitates a regular terminal proof,
demanding keyword 'by' and supporting the full method expression
syntax just like the Isar command 'by'.


*** HOL ***

* Unified theorem tables for both code code generators.  Thus
[code func] has disappeared and only [code] remains.  INCOMPATIBILITY.

* Constant "undefined" replaces "arbitrary" in most occurences.

* Generic ATP manager for Sledgehammer, based on ML threads instead of
Posix processes.  Avoids potentially expensive forking of the ML
process.  New thread-based implementation also works on non-Unix
platforms (Cygwin).  Provers are no longer hardwired, but defined
within the theory via plain ML wrapper functions.  Basic Sledgehammer
commands are covered in the isar-ref manual

* Wrapper scripts for remote SystemOnTPTP service allows to use
sledgehammer without local ATP installation (Vampire etc.).  See also
ISABELLE_HOME/contrib/SystemOnTPTP and the VAMPIRE_HOME setting
variable.  Other provers may be included via suitable ML wrappers, see
also src/HOL/ATP_Linkup.thy.

* Normalization by evaluation now allows non-leftlinear equations.
Declare with attribute [code nbe].

* Command "value" now integrates different evaluation
mechanisms.  The result of the first successful evaluation mechanism
is printed.  In square brackets a particular named evaluation
mechanisms may be specified (currently, [SML], [code] or [nbe]).  See
further src/HOL/ex/Eval_Examples.thy.

* HOL/Orderings: class "wellorder" moved here, with explicit induction
rule "less_induct" as assumption.  For instantiation of "wellorder" by
means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.

* HOL/Orderings: added class "preorder" as superclass of "order".
INCOMPATIBILITY: Instantiation proofs for order, linorder
etc. slightly changed.  Some theorems named order_class.* now named
preorder_class.*.

* HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
moved to separate class dvd in Ring_and_Field; a couple of lemmas on
dvd has been generalized to class comm_semiring_1.  Likewise a bunch
of lemmas from Divides has been generalized from nat to class
semiring_div.  INCOMPATIBILITY.  This involves the following theorem
renames resulting from duplicate elimination:

    dvd_def_mod ~>          dvd_eq_mod_eq_0
    zero_dvd_iff ~>         dvd_0_left_iff
    dvd_0 ~>                dvd_0_right
    DIVISION_BY_ZERO_DIV ~> div_by_0
    DIVISION_BY_ZERO_MOD ~> mod_by_0
    mult_div ~>             div_mult_self2_is_id
    mult_mod ~>             mod_mult_self2_is_0

* HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
zlcm (for int); carried together from various gcd/lcm developements in
the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
recover tupled syntax, use syntax declarations like:

    hide (open) const gcd
    abbreviation gcd where
      "gcd == (%(a, b). GCD.gcd a b)"
    notation (output)
      GCD.gcd ("gcd '(_, _')")

(analogously for lcm, zgcd, zlcm).

* HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.

* New ML antiquotation @{code}: takes constant as argument, generates
corresponding code in background and inserts name of the corresponding
resulting ML value/function/datatype constructor binding in place.
All occurrences of @{code} with a single ML block are generated
simultaneously.  Provides a generic and safe interface for
instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
application.  In future you ought refrain from ad-hoc compiling
generated SML code on the ML toplevel.  Note that (for technical
reasons) @{code} cannot refer to constants for which user-defined
serializations are set.  Refer to the corresponding ML counterpart
directly in that cases.

* Integrated image HOL-Complex with HOL.  Entry points Main.thy and
Complex_Main.thy remain as they are.

* New image HOL-Plain provides a minimal HOL with the most important
tools available (inductive, datatype, primrec, ...).  By convention
the corresponding theory Plain should be ancestor of every further
(library) theory.  Some library theories now have ancestor Plain
(instead of Main), thus theory Main occasionally has to be imported
explicitly.

* The metis method now fails in the usual manner, rather than raising
an exception, if it determines that it cannot prove the theorem.

* Methods "case_tac" and "induct_tac" now refer to the very same rules
as the structured Isar versions "cases" and "induct", cf. the
corresponding "cases" and "induct" attributes.  Mutual induction rules
are now presented as a list of individual projections
(e.g. foo_bar.inducts for types foo and bar); the old format with
explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
rare situations a different rule is selected --- notably nested tuple
elimination instead of former prod.exhaust: use explicit (case_tac t
rule: prod.exhaust) here.

* Attributes "cases", "induct", "coinduct" support "del" option.

* Removed fact "case_split_thm", which duplicates "case_split".

* Command 'rep_datatype': instead of theorem names the command now
takes a list of terms denoting the constructors of the type to be
represented as datatype.  The characteristic theorems have to be
proven.  INCOMPATIBILITY.  Also observe that the following theorems
have disappeared in favour of existing ones:

    unit_induct                 ~> unit.induct
    prod_induct                 ~> prod.induct
    sum_induct                  ~> sum.induct
    Suc_Suc_eq                  ~> nat.inject
    Suc_not_Zero Zero_not_Suc   ~> nat.distinct

* Library/Nat_Infinity: added addition, numeral syntax and more
instantiations for algebraic structures.  Removed some duplicate
theorems.  Changes in simp rules.  INCOMPATIBILITY.

* ATP selection (E/Vampire/Spass) is now via Proof General's settings
menu.


*** HOL-Algebra ***

* New locales for orders and lattices where the equivalence relation
  is not restricted to equality.  INCOMPATIBILITY: all order and
  lattice locales use a record structure with field eq for the
  equivalence.

* New theory of factorial domains.

* Units_l_inv and Units_r_inv are now simprules by default.
INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
and/or r_inv will now also require deletion of these lemmas.

* Renamed the following theorems.  INCOMPATIBILITY.
UpperD ~> Upper_memD
LowerD ~> Lower_memD
least_carrier ~> least_closed
greatest_carrier ~> greatest_closed
greatest_Lower_above ~> greatest_Lower_below
one_zero ~> carrier_one_zero
one_not_zero ~> carrier_one_not_zero  (collision with assumption)


*** HOL-NSA ***

* Created new image HOL-NSA, containing theories of nonstandard
analysis which were previously part of HOL-Complex.  Entry point
Hyperreal.thy remains valid, but theories formerly using
Complex_Main.thy should now use new entry point Hypercomplex.thy.


*** ZF ***

* Proof of Zorn's Lemma for partial orders.


*** ML ***

* Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
to 'a -> thm, while results are always tagged with an authentic oracle
name.  The Isar command 'oracle' is now polymorphic, no argument type
is specified.  INCOMPATIBILITY, need to simplify existing oracle code
accordingly.  Note that extra performance may be gained by producing
the cterm carefully, avoiding slow Thm.cterm_of.

* ML bindings produced via Isar commands are stored within the Isar
context (theory or proof).  Consequently, commands like 'use' and 'ML'
become thread-safe and work with undo as expected (concerning
top-level bindings, not side-effects on global references).
INCOMPATIBILITY, need to provide proper Isar context when invoking the
compiler at runtime; really global bindings need to be given outside a
theory. [Poly/ML 5.2 or later]

* Command 'ML_prf' is analogous to 'ML' but works within a proof
context. Top-level ML bindings are stored within the proof context in
a purely sequential fashion, disregarding the nested proof structure.
ML bindings introduced by 'ML_prf' are discarded at the end of the
proof.  [Poly/ML 5.2 or later]

* Generic Toplevel.add_hook interface allows to analyze the result of
transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
for theorem dependency output of transactions resulting in a new
theory state.

* Name bindings in higher specification mechanisms (notably
LocalTheory.define, LocalTheory.note, and derived packages) are now
formalized as type Name.binding, replacing old bstring.
INCOMPATIBILITY, need to wrap strings via Name.binding function, see
also Name.name_of.  Packages should pass name bindings given by the
user to underlying specification mechanisms; this enables precise
tracking of source positions, for example.

* Result facts (from PureThy.note_thms, ProofContext.note_thms,
LocalTheory.note etc.) now refer to the *full* internal name, not the
bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!

* Rules and tactics that read instantiations (read_instantiate,
res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
context, which is required for parsing and type-checking.  Moreover,
the variables are specified as plain indexnames, not string encodings
thereof.  INCOMPATIBILITY.

* Disposed old type and term read functions (Sign.read_def_typ,
Sign.read_typ, Sign.read_def_terms, Sign.read_term,
Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
Syntax.read_term_global etc.; see also OldGoals.read_term as last
resort for legacy applications.

* Antiquotations: block-structured compilation context indicated by
\<lbrace> ... \<rbrace>; additional antiquotation forms:

  @{let ?pat = term}                      - term abbreviation (HO matching)
  @{note name = fact}                     - fact abbreviation
  @{thm fact}                             - singleton fact (with attributes)
  @{thms fact}                            - general fact (with attributes)
  @{lemma prop by method}                 - singleton goal
  @{lemma prop by meth1 meth2}            - singleton goal
  @{lemma prop1 ... propN by method}      - general goal
  @{lemma prop1 ... propN by meth1 meth2} - general goal
  @{lemma (open) ...}                     - open derivation


*** System ***

* Multithreading for Poly/ML 5.1 is no longer supported, only for
Poly/ML 5.2 or later.

* The Isabelle "emacs" tool provides a specific interface to invoke
Proof General / Emacs, with more explicit failure if that is not
installed (the old isabelle-interface script silently falls back on
isabelle-process).  The PROOFGENERAL_HOME setting determines the
installation location of the Proof General distribution.

* Isabelle/lib/classes/Pure.jar provides basic support to integrate
the Isabelle process into a JVM/Scala application.  See
Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
process wrapper has been discontinued.)

* Status messages (with exact source position information) are
emitted, if proper markup print mode is enabled.  This allows
user-interface components to provide detailed feedback on internal
prover operations.

* Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.



New in Isabelle2008 (June 2008)
-------------------------------

*** General ***

* The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
and updated, with formally checked references as hyperlinks.

* Theory loader: use_thy (and similar operations) no longer set the
implicit ML context, which was occasionally hard to predict and in
conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
provides a proper context already.

* Theory loader: old-style ML proof scripts being *attached* to a thy
file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
'use' within a theory file will do the job.

* Name space merge now observes canonical order, i.e. the second space
is inserted into the first one, while existing entries in the first
space take precedence.  INCOMPATIBILITY in rare situations, may try to
swap theory imports.

* Syntax: symbol \<chi> is now considered a letter.  Potential
INCOMPATIBILITY in identifier syntax etc.

* Outer syntax: string tokens no longer admit escaped white space,
which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
white space without escapes.

* Outer syntax: string tokens may contain arbitrary character codes
specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
"foo_bar".


*** Pure ***

* Context-dependent token translations.  Default setup reverts locally
fixed variables, and adds hilite markup for undeclared frees.

* Unused theorems can be found using the new command 'unused_thms'.
There are three ways of invoking it:

(1) unused_thms
     Only finds unused theorems in the current theory.

(2) unused_thms thy_1 ... thy_n -
     Finds unused theorems in the current theory and all of its ancestors,
     excluding the theories thy_1 ... thy_n and all of their ancestors.

(3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
     Finds unused theorems in the theories thy'_1 ... thy'_m and all of
     their ancestors, excluding the theories thy_1 ... thy_n and all of
     their ancestors.

In order to increase the readability of the list produced by
unused_thms, theorems that have been created by a particular instance
of a theory command such as 'inductive' or 'function' are considered
to belong to the same "group", meaning that if at least one theorem in
this group is used, the other theorems in the same group are no longer
reported as unused.  Moreover, if all theorems in the group are
unused, only one theorem in the group is displayed.

Note that proof objects have to be switched on in order for
unused_thms to work properly (i.e. !proofs must be >= 1, which is
usually the case when using Proof General with the default settings).

* Authentic naming of facts disallows ad-hoc overwriting of previous
theorems within the same name space.  INCOMPATIBILITY, need to remove
duplicate fact bindings, or even accidental fact duplications.  Note
that tools may maintain dynamically scoped facts systematically, using
PureThy.add_thms_dynamic.

* Command 'hide' now allows to hide from "fact" name space as well.

* Eliminated destructive theorem database, simpset, claset, and
clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
update of theories within ML code.

* Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
INCOMPATIBILITY, object-logics depending on former Pure require
additional setup PureThy.old_appl_syntax_setup; object-logics
depending on former CPure need to refer to Pure.

* Commands 'use' and 'ML' are now purely functional, operating on
theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
INCOMPATIBILITY.

* Command 'setup': discontinued implicit version with ML reference.

* Instantiation target allows for simultaneous specification of class
instance operations together with an instantiation proof.
Type-checking phase allows to refer to class operations uniformly.
See src/HOL/Complex/Complex.thy for an Isar example and
src/HOL/Library/Eval.thy for an ML example.

* Indexing of literal facts: be more serious about including only
facts from the visible specification/proof context, but not the
background context (locale etc.).  Affects `prop` notation and method
"fact".  INCOMPATIBILITY: need to name facts explicitly in rare
situations.

* Method "cases", "induct", "coinduct": removed obsolete/undocumented
"(open)" option, which used to expose internal bound variables to the
proof text.

* Isar statements: removed obsolete case "rule_context".
INCOMPATIBILITY, better use explicit fixes/assumes.

* Locale proofs: default proof step now includes 'unfold_locales';
hence 'proof' without argument may be used to unfold locale
predicates.


*** Document preparation ***

* Simplified pdfsetup.sty: color/hyperref is used unconditionally for
both pdf and dvi (hyperlinks usually work in xdvi as well); removed
obsolete thumbpdf setup (contemporary PDF viewers do this on the
spot); renamed link color from "darkblue" to "linkcolor" (default
value unchanged, can be redefined via \definecolor); no longer sets
"a4paper" option (unnecessary or even intrusive).

* Antiquotation @{lemma A method} proves proposition A by the given
method (either a method name or a method name plus (optional) method
arguments in parentheses) and prints A just like @{prop A}.


*** HOL ***

* New primrec package.  Specification syntax conforms in style to
definition/function/....  No separate induction rule is provided.  The
"primrec" command distinguishes old-style and new-style specifications
by syntax.  The former primrec package is now named OldPrimrecPackage.
When adjusting theories, beware: constants stemming from new-style
primrec specifications have authentic syntax.

* Metis prover is now an order of magnitude faster, and also works
with multithreading.

* Metis: the maximum number of clauses that can be produced from a
theorem is now given by the attribute max_clauses.  Theorems that
exceed this number are ignored, with a warning printed.

* Sledgehammer no longer produces structured proofs by default. To
enable, declare [[sledgehammer_full = true]].  Attributes
reconstruction_modulus, reconstruction_sorts renamed
sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.

* Method "induct_scheme" derives user-specified induction rules
from well-founded induction and completeness of patterns. This factors
out some operations that are done internally by the function package
and makes them available separately.  See
src/HOL/ex/Induction_Scheme.thy for examples.

* More flexible generation of measure functions for termination
proofs: Measure functions can be declared by proving a rule of the
form "is_measure f" and giving it the [measure_function] attribute.
The "is_measure" predicate is logically meaningless (always true), and
just guides the heuristic.  To find suitable measure functions, the
termination prover sets up the goal "is_measure ?f" of the appropriate
type and generates all solutions by prolog-style backwards proof using
the declared rules.

This setup also deals with rules like 

  "is_measure f ==> is_measure (list_size f)"

which accommodates nested datatypes that recurse through lists.
Similar rules are predeclared for products and option types.

* Turned the type of sets "'a set" into an abbreviation for "'a => bool"

  INCOMPATIBILITIES:

  - Definitions of overloaded constants on sets have to be replaced by
    definitions on => and bool.

  - Some definitions of overloaded operators on sets can now be proved
    using the definitions of the operators on => and bool.  Therefore,
    the following theorems have been renamed:

      subset_def   -> subset_eq
      psubset_def  -> psubset_eq
      set_diff_def -> set_diff_eq
      Compl_def    -> Compl_eq
      Sup_set_def  -> Sup_set_eq
      Inf_set_def  -> Inf_set_eq
      sup_set_def  -> sup_set_eq
      inf_set_def  -> inf_set_eq

  - Due to the incompleteness of the HO unification algorithm, some
    rules such as subst may require manual instantiation, if some of
    the unknowns in the rule is a set.

  - Higher order unification and forward proofs:
    The proof pattern

      have "P (S::'a set)" <...>
      then have "EX S. P S" ..

    no longer works (due to the incompleteness of the HO unification
    algorithm) and must be replaced by the pattern

      have "EX S. P S"
      proof
        show "P S" <...>
      qed

  - Calculational reasoning with subst (or similar rules):
    The proof pattern

      have "P (S::'a set)" <...>
      also have "S = T" <...>
      finally have "P T" .

    no longer works (for similar reasons as the previous example) and
    must be replaced by something like

      have "P (S::'a set)" <...>
      moreover have "S = T" <...>
      ultimately have "P T" by simp

  - Tactics or packages written in ML code:
    Code performing pattern matching on types via

      Type ("set", [T]) => ...

    must be rewritten. Moreover, functions like strip_type or
    binder_types no longer return the right value when applied to a
    type of the form

      T1 => ... => Tn => U => bool

    rather than

      T1 => ... => Tn => U set

* Merged theories Wellfounded_Recursion, Accessible_Part and
Wellfounded_Relations to theory Wellfounded.

* Explicit class "eq" for executable equality.  INCOMPATIBILITY.

* Class finite no longer treats UNIV as class parameter.  Use class
enum from theory Library/Enum instead to achieve a similar effect.
INCOMPATIBILITY.

* Theory List: rule list_induct2 now has explicitly named cases "Nil"
and "Cons".  INCOMPATIBILITY.

* HOL (and FOL): renamed variables in rules imp_elim and swap.
Potential INCOMPATIBILITY.

* Theory Product_Type: duplicated lemmas split_Pair_apply and
injective_fst_snd removed, use split_eta and prod_eqI instead.
Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.

* Theory Nat: removed redundant lemmas that merely duplicate lemmas of
the same name in theory Orderings:

  less_trans
  less_linear
  le_imp_less_or_eq
  le_less_trans
  less_le_trans
  less_not_sym
  less_asym

Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
and different variable names.

* Library/Option_ord.thy: Canonical order on option type.

* Library/RBT.thy: Red-black trees, an efficient implementation of
finite maps.

* Library/Countable.thy: Type class for countable types.

* Theory Int: The representation of numerals has changed.  The infix
operator BIT and the bit datatype with constructors B0 and B1 have
disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
accordingly.

* Theory Nat: definition of <= and < on natural numbers no longer
depend on well-founded relations.  INCOMPATIBILITY.  Definitions
le_def and less_def have disappeared.  Consider lemmas not_less
[symmetric, where ?'a = nat] and less_eq [symmetric] instead.

* Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
(whose purpose mainly is for various fold_set functionals) have been
abandoned in favor of the existing algebraic classes
ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
lower_semilattice (resp. upper_semilattice) and linorder.
INCOMPATIBILITY.

* Theory Transitive_Closure: induct and cases rules now declare proper
case_names ("base" and "step").  INCOMPATIBILITY.

* Theorem Inductive.lfp_ordinal_induct generalized to complete
lattices.  The form set-specific version is available as
Inductive.lfp_ordinal_induct_set.

* Renamed theorems "power.simps" to "power_int.simps".
INCOMPATIBILITY.

* Class semiring_div provides basic abstract properties of semirings
with division and modulo operations.  Subsumes former class dvd_mod.

* Merged theories IntDef, Numeral and IntArith into unified theory
Int.  INCOMPATIBILITY.

* Theory Library/Code_Index: type "index" now represents natural
numbers rather than integers.  INCOMPATIBILITY.

* New class "uminus" with operation "uminus" (split of from class
"minus" which now only has operation "minus", binary).
INCOMPATIBILITY.

* Constants "card", "internal_split", "option_map" now with authentic
syntax.  INCOMPATIBILITY.

* Definitions subset_def, psubset_def, set_diff_def, Compl_def,
le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
Sup_set_def, le_def, less_def, option_map_def now with object
equality.  INCOMPATIBILITY.

* Records. Removed K_record, and replaced it by pure lambda term
%x. c. The simplifier setup is now more robust against eta expansion.
INCOMPATIBILITY: in cases explicitly referring to K_record.

* Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.

* Library/ListVector: new theory of arithmetic vector operations.

* Library/Order_Relation: new theory of various orderings as sets of
pairs.  Defines preorders, partial orders, linear orders and
well-orders on sets and on types.


*** ZF ***

* Renamed some theories to allow to loading both ZF and HOL in the
same session:

  Datatype  -> Datatype_ZF
  Inductive -> Inductive_ZF
  Int       -> Int_ZF
  IntDiv    -> IntDiv_ZF
  Nat       -> Nat_ZF
  List      -> List_ZF
  Main      -> Main_ZF

INCOMPATIBILITY: ZF theories that import individual theories below
Main might need to be adapted.  Regular theory Main is still
available, as trivial extension of Main_ZF.


*** ML ***

* ML within Isar: antiquotation @{const name} or @{const
name(typargs)} produces statically-checked Const term.

* Functor NamedThmsFun: data is available to the user as dynamic fact
(of the same name).  Removed obsolete print command.

* Removed obsolete "use_legacy_bindings" function.

* The ``print mode'' is now a thread-local value derived from a global
template (the former print_mode reference), thus access becomes
non-critical.  The global print_mode reference is for session
management only; user-code should use print_mode_value,
print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.

* Functions system/system_out provide a robust way to invoke external
shell commands, with propagation of interrupts (requires Poly/ML 5.2).
Do not use OS.Process.system etc. from the basis library!


*** System ***

* Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
in accordance with Proof General 3.7, which prefers GNU emacs.

* isatool tty runs Isabelle process with plain tty interaction;
optional line editor may be specified via ISABELLE_LINE_EDITOR
setting, the default settings attempt to locate "ledit" and "rlwrap".

* isatool browser now works with Cygwin as well, using general
"javapath" function defined in Isabelle process environment.

* YXML notation provides a simple and efficient alternative to
standard XML transfer syntax.  See src/Pure/General/yxml.ML and
isatool yxml as described in the Isabelle system manual.

* JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
provides general wrapper for managing an Isabelle process in a robust
fashion, with ``cooked'' output from stdin/stderr.

* Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).

* Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
way of changing the user's settings is via
ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
script.

* Multithreading.max_threads := 0 refers to the number of actual CPU
cores of the underlying machine, which is a good starting point for
optimal performance tuning.  The corresponding usedir option -M allows
"max" as an alias for "0".  WARNING: does not work on certain versions
of Mac OS (with Poly/ML 5.1).

* isabelle-process: non-ML sessions are run with "nice", to reduce the
adverse effect of Isabelle flooding interactive front-ends (notably
ProofGeneral / XEmacs).



New in Isabelle2007 (November 2007)
-----------------------------------

*** General ***

* More uniform information about legacy features, notably a
warning/error of "Legacy feature: ...", depending on the state of the
tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
legacy features will disappear eventually.

* Theory syntax: the header format ``theory A = B + C:'' has been
discontinued in favour of ``theory A imports B C begin''.  Use isatool
fixheaders to convert existing theory files.  INCOMPATIBILITY.

* Theory syntax: the old non-Isar theory file format has been
discontinued altogether.  Note that ML proof scripts may still be used
with Isar theories; migration is usually quite simple with the ML
function use_legacy_bindings.  INCOMPATIBILITY.

* Theory syntax: some popular names (e.g. 'class', 'declaration',
'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
quotes.

* Theory loader: be more serious about observing the static theory
header specifications (including optional directories), but not the
accidental file locations of previously successful loads.  The strict
update policy of former update_thy is now already performed by
use_thy, so the former has been removed; use_thys updates several
theories simultaneously, just as 'imports' within a theory header
specification, but without merging the results.  Potential
INCOMPATIBILITY: may need to refine theory headers and commands
ROOT.ML which depend on load order.

* Theory loader: optional support for content-based file
identification, instead of the traditional scheme of full physical
path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
(cf. the system manual).  The new scheme allows to work with
non-finished theories in persistent session images, such that source
files may be moved later on without requiring reloads.

* Theory loader: old-style ML proof scripts being *attached* to a thy
file (with the same base name as the theory) are considered a legacy
feature, which will disappear eventually. Even now, the theory loader
no longer maintains dependencies on such files.

* Syntax: the scope for resolving ambiguities via type-inference is
now limited to individual terms, instead of whole simultaneous
specifications as before. This greatly reduces the complexity of the
syntax module and improves flexibility by separating parsing and
type-checking. INCOMPATIBILITY: additional type-constraints (explicit
'fixes' etc.) are required in rare situations.

* Syntax: constants introduced by new-style packages ('definition',
'abbreviation' etc.) are passed through the syntax module in
``authentic mode''. This means that associated mixfix annotations
really stick to such constants, independently of potential name space
ambiguities introduced later on. INCOMPATIBILITY: constants in parse
trees are represented slightly differently, may need to adapt syntax
translations accordingly. Use CONST marker in 'translations' and
@{const_syntax} antiquotation in 'parse_translation' etc.

* Legacy goal package: reduced interface to the bare minimum required
to keep existing proof scripts running.  Most other user-level
functions are now part of the OldGoals structure, which is *not* open
by default (consider isatool expandshort before open OldGoals).
Removed top_sg, prin, printyp, pprint_term/typ altogether, because
these tend to cause confusion about the actual goal (!) context being
used here, which is not necessarily the same as the_context().

* Command 'find_theorems': supports "*" wild-card in "name:"
criterion; "with_dups" option.  Certain ProofGeneral versions might
support a specific search form (see ProofGeneral/CHANGES).

* The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
by default, which means that "prems" (and also "fixed variables") are
suppressed from proof state output.  Note that the ProofGeneral
settings mechanism allows to change and save options persistently, but
older versions of Isabelle will fail to start up if a negative prems
limit is imposed.

* Local theory targets may be specified by non-nested blocks of
``context/locale/class ... begin'' followed by ``end''.  The body may
contain definitions, theorems etc., including any derived mechanism
that has been implemented on top of these primitives.  This concept
generalizes the existing ``theorem (in ...)'' towards more versatility
and scalability.

* Proof General interface: proper undo of final 'end' command;
discontinued Isabelle/classic mode (ML proof scripts).


*** Document preparation ***

* Added antiquotation @{theory name} which prints the given name,
after checking that it refers to a valid ancestor theory in the
current context.

* Added antiquotations @{ML_type text} and @{ML_struct text} which
check the given source text as ML type/structure, printing verbatim.

* Added antiquotation @{abbrev "c args"} which prints the abbreviation
"c args == rhs" given in the current context.  (Any number of
arguments may be given on the LHS.)


*** Pure ***

* The 'class' package offers a combination of axclass and locale to
achieve Haskell-like type classes in Isabelle.  Definitions and
theorems within a class context produce both relative results (with
implicit parameters according to the locale context), and polymorphic
constants with qualified polymorphism (according to the class
context).  Within the body context of a 'class' target, a separate
syntax layer ("user space type system") takes care of converting
between global polymorphic consts and internal locale representation.
See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
"isatool doc classes" provides a tutorial.

* Generic code generator framework allows to generate executable
code for ML and Haskell (including Isabelle classes).  A short usage
sketch:

    internal compilation:
        export_code <list of constants (term syntax)> in SML
    writing SML code to a file:
        export_code <list of constants (term syntax)> in SML <filename>
    writing OCaml code to a file:
        export_code <list of constants (term syntax)> in OCaml <filename>
    writing Haskell code to a bunch of files:
        export_code <list of constants (term syntax)> in Haskell <filename>

    evaluating closed propositions to True/False using code generation:
        method ``eval''

Reasonable default setup of framework in HOL.

Theorem attributs for selecting and transforming function equations theorems:

    [code fun]:        select a theorem as function equation for a specific constant
    [code fun del]:    deselect a theorem as function equation for a specific constant
    [code inline]:     select an equation theorem for unfolding (inlining) in place
    [code inline del]: deselect an equation theorem for unfolding (inlining) in place

User-defined serializations (target in {SML, OCaml, Haskell}):

    code_const <and-list of constants (term syntax)>
      {(target) <and-list of const target syntax>}+

    code_type <and-list of type constructors>
      {(target) <and-list of type target syntax>}+

    code_instance <and-list of instances>
      {(target)}+
        where instance ::= <type constructor> :: <class>

    code_class <and_list of classes>
      {(target) <and-list of class target syntax>}+
        where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?

code_instance and code_class only are effective to target Haskell.

For example usage see src/HOL/ex/Codegenerator.thy and
src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
generation from Isabelle/HOL theories is available via "isatool doc
codegen".

* Code generator: consts in 'consts_code' Isar commands are now
referred to by usual term syntax (including optional type
annotations).

* Command 'no_translations' removes translation rules from theory
syntax.

* Overloaded definitions are now actually checked for acyclic
dependencies.  The overloading scheme is slightly more general than
that of Haskell98, although Isabelle does not demand an exact
correspondence to type class and instance declarations.
INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
exotic versions of overloading -- at the discretion of the user!

Polymorphic constants are represented via type arguments, i.e. the
instantiation that matches an instance against the most general
declaration given in the signature.  For example, with the declaration
c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
as c(nat).  Overloading is essentially simultaneous structural
recursion over such type arguments.  Incomplete specification patterns
impose global constraints on all occurrences, e.g. c('a * 'a) on the
LHS means that more general c('a * 'b) will be disallowed on any RHS.
Command 'print_theory' outputs the normalized system of recursive
equations, see section "definitions".

* Configuration options are maintained within the theory or proof
context (with name and type bool/int/string), providing a very simple
interface to a poor-man's version of general context data.  Tools may
declare options in ML (e.g. using Attrib.config_int) and then refer to
these values using Config.get etc.  Users may change options via an
associated attribute of the same name.  This form of context
declaration works particularly well with commands 'declare' or
'using', for example ``declare [[foo = 42]]''.  Thus it has become
very easy to avoid global references, which would not observe Isar
toplevel undo/redo and fail to work with multithreading.

Various global ML references of Pure and HOL have been turned into
configuration options:

  Unify.search_bound		unify_search_bound
  Unify.trace_bound		unify_trace_bound
  Unify.trace_simp		unify_trace_simp
  Unify.trace_types		unify_trace_types
  Simplifier.simp_depth_limit	simp_depth_limit
  Blast.depth_limit		blast_depth_limit
  DatatypeProp.dtK		datatype_distinctness_limit
  fast_arith_neq_limit  	fast_arith_neq_limit
  fast_arith_split_limit	fast_arith_split_limit

* Named collections of theorems may be easily installed as context
data using the functor NamedThmsFun (see also
src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
attributes; there is also a toplevel print command.  This facility is
just a common case of general context data, which is the preferred way
for anything more complex than just a list of facts in canonical
order.

* Isar: command 'declaration' augments a local theory by generic
declaration functions written in ML.  This enables arbitrary content
being added to the context, depending on a morphism that tells the
difference of the original declaration context wrt. the application
context encountered later on.

* Isar: proper interfaces for simplification procedures.  Command
'simproc_setup' declares named simprocs (with match patterns, and body
text in ML).  Attribute "simproc" adds/deletes simprocs in the current
context.  ML antiquotation @{simproc name} retrieves named simprocs.

* Isar: an extra pair of brackets around attribute declarations
abbreviates a theorem reference involving an internal dummy fact,
which will be ignored later --- only the effect of the attribute on
the background context will persist.  This form of in-place
declarations is particularly useful with commands like 'declare' and
'using', for example ``have A using [[simproc a]] by simp''.

* Isar: method "assumption" (and implicit closing of subproofs) now
takes simple non-atomic goal assumptions into account: after applying
an assumption as a rule the resulting subgoals are solved by atomic
assumption steps.  This is particularly useful to finish 'obtain'
goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
without referring to the original premise "!!x. P x ==> thesis" in the
Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
more permissive.

* Isar: implicit use of prems from the Isar proof context is
considered a legacy feature.  Common applications like ``have A .''
may be replaced by ``have A by fact'' or ``note `A`''.  In general,
referencing facts explicitly here improves readability and
maintainability of proof texts.

* Isar: improper proof element 'guess' is like 'obtain', but derives
the obtained context from the course of reasoning!  For example:

  assume "EX x y. A x & B y"   -- "any previous fact"
  then guess x and y by clarify

This technique is potentially adventurous, depending on the facts and
proof tools being involved here.

* Isar: known facts from the proof context may be specified as literal
propositions, using ASCII back-quote syntax.  This works wherever
named facts used to be allowed so far, in proof commands, proof
methods, attributes etc.  Literal facts are retrieved from the context
according to unification of type and term parameters.  For example,
provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
theorems in the current context, then these are valid literal facts:
`A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.

There is also a proof method "fact" which does the same composition
for explicit goal states, e.g. the following proof texts coincide with
certain special cases of literal facts:

  have "A" by fact                 ==  note `A`
  have "A ==> B" by fact           ==  note `A ==> B`
  have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  have "P a ==> Q a" by fact       ==  note `P a ==> Q a`

* Isar: ":" (colon) is no longer a symbolic identifier character in
outer syntax.  Thus symbolic identifiers may be used without
additional white space in declarations like this: ``assume *: A''.

* Isar: 'print_facts' prints all local facts of the current context,
both named and unnamed ones.

* Isar: 'def' now admits simultaneous definitions, e.g.:

  def x == "t" and y == "u"

* Isar: added command 'unfolding', which is structurally similar to
'using', but affects both the goal state and facts by unfolding given
rewrite rules.  Thus many occurrences of the 'unfold' method or
'unfolded' attribute may be replaced by first-class proof text.

* Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
and command 'unfolding' now all support object-level equalities
(potentially conditional).  The underlying notion of rewrite rule is
analogous to the 'rule_format' attribute, but *not* that of the
Simplifier (which is usually more generous).

* Isar: the new attribute [rotated n] (default n = 1) rotates the
premises of a theorem by n. Useful in conjunction with drule.

* Isar: the goal restriction operator [N] (default N = 1) evaluates a
method expression within a sandbox consisting of the first N
sub-goals, which need to exist.  For example, ``simp_all [3]''
simplifies the first three sub-goals, while (rule foo, simp_all)[]
simplifies all new goals that emerge from applying rule foo to the
originally first one.

* Isar: schematic goals are no longer restricted to higher-order
patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
expected.

* Isar: the conclusion of a long theorem statement is now either
'shows' (a simultaneous conjunction, as before), or 'obtains'
(essentially a disjunction of cases with local parameters and
assumptions).  The latter allows to express general elimination rules
adequately; in this notation common elimination rules look like this:

  lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
    assumes "EX x. P x"
    obtains x where "P x"

  lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
    assumes "A & B"
    obtains A and B

  lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
    assumes "A | B"
    obtains
      A
    | B

The subsequent classical rules even refer to the formal "thesis"
explicitly:

  lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
    obtains "~ thesis"

  lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
    obtains "thesis ==> something"

The actual proof of an 'obtains' statement is analogous to that of the
Isar proof element 'obtain', only that there may be several cases.
Optional case names may be specified in parentheses; these will be
available both in the present proof and as annotations in the
resulting rule, for later use with the 'cases' method (cf. attribute
case_names).

* Isar: the assumptions of a long theorem statement are available as
"assms" fact in the proof context.  This is more appropriate than the
(historical) "prems", which refers to all assumptions of the current
context, including those from the target locale, proof body etc.

* Isar: 'print_statement' prints theorems from the current theory or
proof context in long statement form, according to the syntax of a
top-level lemma.

* Isar: 'obtain' takes an optional case name for the local context
introduction rule (default "that").

* Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
explicit (is "_ ==> ?foo") in the rare cases where this still happens
to occur.

* Pure: syntax "CONST name" produces a fully internalized constant
according to the current context.  This is particularly useful for
syntax translations that should refer to internal constant
representations independently of name spaces.

* Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
instead of "FOO ". This allows multiple binder declarations to coexist
in the same context.  INCOMPATIBILITY.

* Isar/locales: 'notation' provides a robust interface to the 'syntax'
primitive that also works in a locale context (both for constants and
fixed variables). Type declaration and internal syntactic representation
of given constants retrieved from the context. Likewise, the
'no_notation' command allows to remove given syntax annotations from the
current context.

* Isar/locales: new derived specification elements 'axiomatization',
'definition', 'abbreviation', which support type-inference, admit
object-level specifications (equality, equivalence).  See also the
isar-ref manual.  Examples:

  axiomatization
    eq  (infix "===" 50) where
    eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"

  definition "f x y = x + y + 1"
  definition g where "g x = f x x"

  abbreviation
    neq  (infix "=!=" 50) where
    "x =!= y == ~ (x === y)"

These specifications may be also used in a locale context.  Then the
constants being introduced depend on certain fixed parameters, and the
constant name is qualified by the locale base name.  An internal
abbreviation takes care for convenient input and output, making the
parameters implicit and using the original short name.  See also
src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
entities from a monomorphic theory.

Presently, abbreviations are only available 'in' a target locale, but
not inherited by general import expressions.  Also note that
'abbreviation' may be used as a type-safe replacement for 'syntax' +
'translations' in common applications.  The "no_abbrevs" print mode
prevents folding of abbreviations in term output.

Concrete syntax is attached to specified constants in internal form,
independently of name spaces.  The parse tree representation is
slightly different -- use 'notation' instead of raw 'syntax', and
'translations' with explicit "CONST" markup to accommodate this.

* Pure/Isar: unified syntax for new-style specification mechanisms
(e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
full type inference and dummy patterns ("_").  For example:

  definition "K x _ = x"

  inductive conj for A B
  where "A ==> B ==> conj A B"

* Pure: command 'print_abbrevs' prints all constant abbreviations of
the current context.  Print mode "no_abbrevs" prevents inversion of
abbreviations on output.

* Isar/locales: improved parameter handling: use of locales "var" and
"struct" no longer necessary; - parameter renamings are no longer
required to be injective.  For example, this allows to define
endomorphisms as locale endom = homom mult mult h.

* Isar/locales: changed the way locales with predicates are defined.
Instead of accumulating the specification, the imported expression is
now an interpretation.  INCOMPATIBILITY: different normal form of
locale expressions.  In particular, in interpretations of locales with
predicates, goals repesenting already interpreted fragments are not
removed automatically.  Use methods `intro_locales' and
`unfold_locales'; see below.

* Isar/locales: new methods `intro_locales' and `unfold_locales'
provide backward reasoning on locales predicates.  The methods are
aware of interpretations and discharge corresponding goals.
`intro_locales' is less aggressive then `unfold_locales' and does not
unfold predicates to assumptions.

* Isar/locales: the order in which locale fragments are accumulated
has changed.  This enables to override declarations from fragments due
to interpretations -- for example, unwanted simp rules.

* Isar/locales: interpretation in theories and proof contexts has been
extended.  One may now specify (and prove) equations, which are
unfolded in interpreted theorems.  This is useful for replacing
defined concepts (constants depending on locale parameters) by
concepts already existing in the target context.  Example:

  interpretation partial_order ["op <= :: [int, int] => bool"]
    where "partial_order.less (op <=) (x::int) y = (x < y)"

Typically, the constant `partial_order.less' is created by a
definition specification element in the context of locale
partial_order.

* Method "induct": improved internal context management to support
local fixes and defines on-the-fly. Thus explicit meta-level
connectives !!  and ==> are rarely required anymore in inductive goals
(using object-logic connectives for this purpose has been long
obsolete anyway). Common proof patterns are explained in
src/HOL/Induct/Common_Patterns.thy, see also
src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
examples.

* Method "induct": improved handling of simultaneous goals. Instead of
introducing object-level conjunction, the statement is now split into
several conclusions, while the corresponding symbolic cases are nested
accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
see src/HOL/Induct/Common_Patterns.thy, for example.

* Method "induct": mutual induction rules are now specified as a list
of rule sharing the same induction cases. HOL packages usually provide
foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
mutual induction rules differently, i.e. like this:

  (induct rule: foo_bar.inducts)
  (induct set: foo bar)
  (induct pred: foo bar)
  (induct type: foo bar)

The ML function ProjectRule.projections turns old-style rules into the
new format.

* Method "coinduct": dual of induction, see
src/HOL/Library/Coinductive_List.thy for various examples.

* Method "cases", "induct", "coinduct": the ``(open)'' option is
considered a legacy feature.

* Attribute "symmetric" produces result with standardized schematic
variables (index 0).  Potential INCOMPATIBILITY.

* Simplifier: by default the simplifier trace only shows top level
rewrites now. That is, trace_simp_depth_limit is set to 1 by
default. Thus there is less danger of being flooded by the trace. The
trace indicates where parts have been suppressed.
  
* Provers/classical: removed obsolete classical version of elim_format
attribute; classical elim/dest rules are now treated uniformly when
manipulating the claset.

* Provers/classical: stricter checks to ensure that supplied intro,
dest and elim rules are well-formed; dest and elim rules must have at
least one premise.

* Provers/classical: attributes dest/elim/intro take an optional
weight argument for the rule (just as the Pure versions).  Weights are
ignored by automated tools, but determine the search order of single
rule steps.

* Syntax: input syntax now supports dummy variable binding "%_. b",
where the body does not mention the bound variable.  Note that dummy
patterns implicitly depend on their context of bounds, which makes
"{_. _}" match any set comprehension as expected.  Potential
INCOMPATIBILITY -- parse translations need to cope with syntactic
constant "_idtdummy" in the binding position.

* Syntax: removed obsolete syntactic constant "_K" and its associated
parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
for example "A -> B" => "Pi A (%_. B)".

* Pure: 'class_deps' command visualizes the subclass relation, using
the graph browser tool.

* Pure: 'print_theory' now suppresses certain internal declarations by
default; use '!' option for full details.


*** HOL ***

* Method "metis" proves goals by applying the Metis general-purpose
resolution prover (see also http://gilith.com/software/metis/).
Examples are in the directory MetisExamples.  WARNING: the
Isabelle/HOL-Metis integration does not yet work properly with
multi-threading.
  
* Command 'sledgehammer' invokes external automatic theorem provers as
background processes.  It generates calls to the "metis" method if
successful. These can be pasted into the proof.  Users do not have to
wait for the automatic provers to return.  WARNING: does not really
work with multi-threading.

* New "auto_quickcheck" feature tests outermost goal statements for
potential counter-examples.  Controlled by ML references
auto_quickcheck (default true) and auto_quickcheck_time_limit (default
5000 milliseconds).  Fails silently if statements is outside of
executable fragment, or any other codgenerator problem occurs.

* New constant "undefined" with axiom "undefined x = undefined".

* Added class "HOL.eq", allowing for code generation with polymorphic
equality.

* Some renaming of class constants due to canonical name prefixing in
the new 'class' package:

    HOL.abs ~> HOL.abs_class.abs
    HOL.divide ~> HOL.divide_class.divide
    0 ~> HOL.zero_class.zero
    1 ~> HOL.one_class.one
    op + ~> HOL.plus_class.plus
    op - ~> HOL.minus_class.minus
    uminus ~> HOL.minus_class.uminus
    op * ~> HOL.times_class.times
    op < ~> HOL.ord_class.less
    op <= > HOL.ord_class.less_eq
    Nat.power ~> Power.power_class.power
    Nat.size ~> Nat.size_class.size
    Numeral.number_of ~> Numeral.number_class.number_of
    FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
    FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
    Orderings.min ~> Orderings.ord_class.min
    Orderings.max ~> Orderings.ord_class.max
    Divides.op div ~> Divides.div_class.div
    Divides.op mod ~> Divides.div_class.mod
    Divides.op dvd ~> Divides.div_class.dvd

INCOMPATIBILITY.  Adaptions may be required in the following cases:

a) User-defined constants using any of the names "plus", "minus",
"times", "less" or "less_eq". The standard syntax translations for
"+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
names.

b) Variables named "plus", "minus", "times", "less", "less_eq"
INCOMPATIBILITY: use more specific names.

c) Permutative equations (e.g. "a + b = b + a")
Since the change of names also changes the order of terms, permutative
rewrite rules may get applied in a different order. Experience shows
that this is rarely the case (only two adaptions in the whole Isabelle
distribution).  INCOMPATIBILITY: rewrite proofs

d) ML code directly refering to constant names
This in general only affects hand-written proof tactics, simprocs and
so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
Consider using @{const_name} antiquotation.

* New class "default" with associated constant "default".

* Function "sgn" is now overloaded and available on int, real, complex
(and other numeric types), using class "sgn".  Two possible defs of
sgn are given as equational assumptions in the classes sgn_if and
sgn_div_norm; ordered_idom now also inherits from sgn_if.
INCOMPATIBILITY.

* Locale "partial_order" now unified with class "order" (cf. theory
Orderings), added parameter "less".  INCOMPATIBILITY.

* Renamings in classes "order" and "linorder": facts "refl", "trans" and
"cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
clashes with HOL "refl" and "trans".  INCOMPATIBILITY.

* Classes "order" and "linorder": potential INCOMPATIBILITY due to
changed order of proof goals in instance proofs.

* The transitivity reasoner for partial and linear orders is set up
for classes "order" and "linorder".  Instances of the reasoner are available
in all contexts importing or interpreting the corresponding locales.
Method "order" invokes the reasoner separately; the reasoner
is also integrated with the Simplifier as a solver.  Diagnostic
command 'print_orders' shows the available instances of the reasoner
in the current context.

* Localized monotonicity predicate in theory "Orderings"; integrated
lemmas max_of_mono and min_of_mono with this predicate.
INCOMPATIBILITY.

* Formulation of theorem "dense" changed slightly due to integration
with new class dense_linear_order.

* Uniform lattice theory development in HOL.

    constants "meet" and "join" now named "inf" and "sup"
    constant "Meet" now named "Inf"

    classes "meet_semilorder" and "join_semilorder" now named
      "lower_semilattice" and "upper_semilattice"
    class "lorder" now named "lattice"
    class "comp_lat" now named "complete_lattice"

    Instantiation of lattice classes allows explicit definitions
    for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).

  INCOMPATIBILITY.  Theorem renames:

    meet_left_le            ~> inf_le1
    meet_right_le           ~> inf_le2
    join_left_le            ~> sup_ge1
    join_right_le           ~> sup_ge2
    meet_join_le            ~> inf_sup_ord
    le_meetI                ~> le_infI
    join_leI                ~> le_supI
    le_meet                 ~> le_inf_iff
    le_join                 ~> ge_sup_conv
    meet_idempotent         ~> inf_idem
    join_idempotent         ~> sup_idem
    meet_comm               ~> inf_commute
    join_comm               ~> sup_commute
    meet_leI1               ~> le_infI1
    meet_leI2               ~> le_infI2
    le_joinI1               ~> le_supI1
    le_joinI2               ~> le_supI2
    meet_assoc              ~> inf_assoc
    join_assoc              ~> sup_assoc
    meet_left_comm          ~> inf_left_commute
    meet_left_idempotent    ~> inf_left_idem
    join_left_comm          ~> sup_left_commute
    join_left_idempotent    ~> sup_left_idem
    meet_aci                ~> inf_aci
    join_aci                ~> sup_aci
    le_def_meet             ~> le_iff_inf
    le_def_join             ~> le_iff_sup
    join_absorp2            ~> sup_absorb2
    join_absorp1            ~> sup_absorb1
    meet_absorp1            ~> inf_absorb1
    meet_absorp2            ~> inf_absorb2
    meet_join_absorp        ~> inf_sup_absorb
    join_meet_absorp        ~> sup_inf_absorb
    distrib_join_le         ~> distrib_sup_le
    distrib_meet_le         ~> distrib_inf_le

    add_meet_distrib_left   ~> add_inf_distrib_left
    add_join_distrib_left   ~> add_sup_distrib_left
    is_join_neg_meet        ~> is_join_neg_inf
    is_meet_neg_join        ~> is_meet_neg_sup
    add_meet_distrib_right  ~> add_inf_distrib_right
    add_join_distrib_right  ~> add_sup_distrib_right
    add_meet_join_distribs  ~> add_sup_inf_distribs
    join_eq_neg_meet        ~> sup_eq_neg_inf
    meet_eq_neg_join        ~> inf_eq_neg_sup
    add_eq_meet_join        ~> add_eq_inf_sup
    meet_0_imp_0            ~> inf_0_imp_0
    join_0_imp_0            ~> sup_0_imp_0
    meet_0_eq_0             ~> inf_0_eq_0
    join_0_eq_0             ~> sup_0_eq_0
    neg_meet_eq_join        ~> neg_inf_eq_sup
    neg_join_eq_meet        ~> neg_sup_eq_inf
    join_eq_if              ~> sup_eq_if

    mono_meet               ~> mono_inf
    mono_join               ~> mono_sup
    meet_bool_eq            ~> inf_bool_eq
    join_bool_eq            ~> sup_bool_eq
    meet_fun_eq             ~> inf_fun_eq
    join_fun_eq             ~> sup_fun_eq
    meet_set_eq             ~> inf_set_eq
    join_set_eq             ~> sup_set_eq
    meet1_iff               ~> inf1_iff
    meet2_iff               ~> inf2_iff
    meet1I                  ~> inf1I
    meet2I                  ~> inf2I
    meet1D1                 ~> inf1D1
    meet2D1                 ~> inf2D1
    meet1D2                 ~> inf1D2
    meet2D2                 ~> inf2D2
    meet1E                  ~> inf1E
    meet2E                  ~> inf2E
    join1_iff               ~> sup1_iff
    join2_iff               ~> sup2_iff
    join1I1                 ~> sup1I1
    join2I1                 ~> sup2I1
    join1I1                 ~> sup1I1
    join2I2                 ~> sup1I2
    join1CI                 ~> sup1CI
    join2CI                 ~> sup2CI
    join1E                  ~> sup1E
    join2E                  ~> sup2E

    is_meet_Meet            ~> is_meet_Inf
    Meet_bool_def           ~> Inf_bool_def
    Meet_fun_def            ~> Inf_fun_def
    Meet_greatest           ~> Inf_greatest
    Meet_lower              ~> Inf_lower
    Meet_set_def            ~> Inf_set_def

    Sup_def                 ~> Sup_Inf
    Sup_bool_eq             ~> Sup_bool_def
    Sup_fun_eq              ~> Sup_fun_def
    Sup_set_eq              ~> Sup_set_def

    listsp_meetI            ~> listsp_infI
    listsp_meet_eq          ~> listsp_inf_eq

    meet_min                ~> inf_min
    join_max                ~> sup_max

* Added syntactic class "size"; overloaded constant "size" now has
type "'a::size ==> bool"

* Internal reorganisation of `size' of datatypes: size theorems
"foo.size" are no longer subsumed by "foo.simps" (but are still
simplification rules by default!); theorems "prod.size" now named
"*.size".

* Class "div" now inherits from class "times" rather than "type".
INCOMPATIBILITY.

* HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
Linorder etc.  have disappeared; operations defined in terms of
fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.

* HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.

* HOL-Word: New extensive library and type for generic, fixed size
machine words, with arithemtic, bit-wise, shifting and rotating
operations, reflection into int, nat, and bool lists, automation for
linear arithmetic (by automatic reflection into nat or int), including
lemmas on overflow and monotonicity.  Instantiated to all appropriate
arithmetic type classes, supporting automatic simplification of
numerals on all operations.

* Library/Boolean_Algebra: locales for abstract boolean algebras.

* Library/Numeral_Type: numbers as types, e.g. TYPE(32).

* Code generator library theories:
  - Code_Integer represents HOL integers by big integer literals in target
    languages.
  - Code_Char represents HOL characters by character literals in target
    languages.
  - Code_Char_chr like Code_Char, but also offers treatment of character
    codes; includes Code_Integer.
  - Executable_Set allows to generate code for finite sets using lists.
  - Executable_Rat implements rational numbers as triples (sign, enumerator,
    denominator).
  - Executable_Real implements a subset of real numbers, namly those
    representable by rational numbers.
  - Efficient_Nat implements natural numbers by integers, which in general will
    result in higher efficency; pattern matching with 0/Suc is eliminated;
    includes Code_Integer.
  - Code_Index provides an additional datatype index which is mapped to
    target-language built-in integers.
  - Code_Message provides an additional datatype message_string which is isomorphic to
    strings; messages are mapped to target-language strings.

* New package for inductive predicates

  An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via

    inductive
      p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
      for z_1 :: U_1 and ... and z_n :: U_m
    where
      rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
    | ...

  with full support for type-inference, rather than

    consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"

    abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
    where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"

    inductive "s z_1 ... z_m"
    intros
      rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
      ...

  For backward compatibility, there is a wrapper allowing inductive
  sets to be defined with the new package via

    inductive_set
      s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
      for z_1 :: U_1 and ... and z_n :: U_m
    where
      rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
    | ...

  or

    inductive_set
      s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
      and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
      for z_1 :: U_1 and ... and z_n :: U_m
    where
      "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
    | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
    | ...

  if the additional syntax "p ..." is required.

  Numerous examples can be found in the subdirectories src/HOL/Auth,
  src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.

  INCOMPATIBILITIES:

  - Since declaration and definition of inductive sets or predicates
    is no longer separated, abbreviations involving the newly
    introduced sets or predicates must be specified together with the
    introduction rules after the 'where' keyword (see above), rather
    than before the actual inductive definition.

  - The variables in induction and elimination rules are now
    quantified in the order of their occurrence in the introduction
    rules, rather than in alphabetical order. Since this may break
    some proofs, these proofs either have to be repaired, e.g. by
    reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
    statements of the form

      case (rule_i a_i_1 ... a_i_{k_i})

    or the old order of quantification has to be restored by explicitly adding
    meta-level quantifiers in the introduction rules, i.e.

      | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"

  - The format of the elimination rules is now

      p z_1 ... z_m x_1 ... x_n ==>
        (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
        ==> ... ==> P

    for predicates and

      (x_1, ..., x_n) : s z_1 ... z_m ==>
        (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
        ==> ... ==> P

    for sets rather than

      x : s z_1 ... z_m ==>
        (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
        ==> ... ==> P

    This may require terms in goals to be expanded to n-tuples
    (e.g. using case_tac or simplification with the split_paired_all
    rule) before the above elimination rule is applicable.

  - The elimination or case analysis rules for (mutually) inductive
    sets or predicates are now called "p_1.cases" ... "p_k.cases". The
    list of rules "p_1_..._p_k.elims" is no longer available.

* New package "function"/"fun" for general recursive functions,
supporting mutual and nested recursion, definitions in local contexts,
more general pattern matching and partiality. See HOL/ex/Fundefs.thy
for small examples, and the separate tutorial on the function
package. The old recdef "package" is still available as before, but
users are encouraged to use the new package.

* Method "lexicographic_order" automatically synthesizes termination
relations as lexicographic combinations of size measures. 

* Case-expressions allow arbitrary constructor-patterns (including
"_") and take their order into account, like in functional
programming.  Internally, this is translated into nested
case-expressions; missing cases are added and mapped to the predefined
constant "undefined". In complicated cases printing may no longer show
the original input but the internal form. Lambda-abstractions allow
the same form of pattern matching: "% pat1 => e1 | ..." is an
abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
variable.

* IntDef: The constant "int :: nat => int" has been removed; now "int"
is an abbreviation for "of_nat :: nat => int". The simplification
rules for "of_nat" have been changed to work like "int" did
previously.  Potential INCOMPATIBILITY:
  - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  - of_nat_diff and of_nat_mult are no longer default simp rules

* Method "algebra" solves polynomial equations over (semi)rings using
Groebner bases. The (semi)ring structure is defined by locales and the
tool setup depends on that generic context. Installing the method for
a specific type involves instantiating the locale and possibly adding
declarations for computation on the coefficients.  The method is
already instantiated for natural numbers and for the axiomatic class
of idoms with numerals.  See also the paper by Chaieb and Wenzel at
CALCULEMUS 2007 for the general principles underlying this
architecture of context-aware proof-tools.

* Method "ferrack" implements quantifier elimination over
special-purpose dense linear orders using locales (analogous to
"algebra"). The method is already installed for class
{ordered_field,recpower,number_ring} which subsumes real, hyperreal,
rat, etc.

* Former constant "List.op @" now named "List.append".  Use ML
antiquotations @{const_name List.append} or @{term " ... @ ... "} to
circumvent possible incompatibilities when working on ML level.

* primrec: missing cases mapped to "undefined" instead of "arbitrary".

* New function listsum :: 'a list => 'a for arbitrary monoids.
Special syntax: "SUM x <- xs. f x" (and latex variants)

* New syntax for Haskell-like list comprehension (input only), eg.
[(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.

* The special syntax for function "filter" has changed from [x :
xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
comprehension syntax, and for uniformity.  INCOMPATIBILITY.

* [a..b] is now defined for arbitrary linear orders.  It used to be
defined on nat only, as an abbreviation for [a..<Suc b]
INCOMPATIBILITY.

* Renamed lemma "set_take_whileD"  to "set_takeWhileD".

* New functions "sorted" and "sort" in src/HOL/List.thy.

* New lemma collection field_simps (an extension of ring_simps) for
manipulating (in)equations involving division. Multiplies with all
denominators that can be proved to be non-zero (in equations) or
positive/negative (in inequations).

* Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
have been improved and renamed to ring_simps, group_simps and
ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
because they were subsumed by lemmas xyz.  INCOMPATIBILITY.

* Theory Library/Commutative_Ring: switched from recdef to function
package; constants add, mul, pow now curried.  Infix syntax for
algebraic operations.

* Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
INCOMPATIBILITY.

* Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
INCOMPATIBILITY.

* HOL/records: generalised field-update to take a function on the
field rather than the new value: r(|A := x|) is translated to A_update
(K x) r The K-combinator that is internally used is called K_record.
INCOMPATIBILITY: Usage of the plain update functions has to be
adapted.
 
* Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
* x = 0, which are required for a semiring.  Richer structures do not
inherit from semiring_0 anymore, because this property is a theorem
there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
there is more to prove, but this is mostly trivial.

* Class "recpower" is generalized to arbitrary monoids, not just
commutative semirings.  INCOMPATIBILITY: may need to incorporate
commutativity or semiring properties additionally.

* Constant "List.list_all2" in List.thy now uses authentic syntax.
INCOMPATIBILITY: translations containing list_all2 may go wrong,
better use 'abbreviation'.

* Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.

* Numeral syntax: type 'bin' which was a mere type copy of 'int' has
been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
significant changes for setting up numeral syntax for types:
  - New constants Numeral.pred and Numeral.succ instead
      of former Numeral.bin_pred and Numeral.bin_succ.
  - Use integer operations instead of bin_add, bin_mult and so on.
  - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.

See src/HOL/Integ/IntArith.thy for an example setup.

* Command 'normal_form' computes the normal form of a term that may
contain free variables.  For example ``normal_form "rev [a, b, c]"''
produces ``[b, c, a]'' (without proof).  This command is suitable for
heavy-duty computations because the functions are compiled to ML
first.  Correspondingly, a method "normalization" is provided.  See
further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.

* Alternative iff syntax "A <-> B" for equality on bool (with priority
25 like -->); output depends on the "iff" print_mode, the default is
"A = B" (with priority 50).

* Relations less (<) and less_eq (<=) are also available on type bool.
Modified syntax to disallow nesting without explicit parentheses,
e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
INCOMPATIBILITY.

* "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).

* Relation composition operator "op O" now has precedence 75 and binds
stronger than union and intersection. INCOMPATIBILITY.

* The old set interval syntax "{m..n(}" (and relatives) has been
removed.  Use "{m..<n}" (and relatives) instead.

* In the context of the assumption "~(s = t)" the Simplifier rewrites
"t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
``declare [[simproc del: neq]]''.

* Simplifier: "m dvd n" where m and n are numbers is evaluated to
True/False.

* Theorem Cons_eq_map_conv no longer declared as "simp".

* Theorem setsum_mult renamed to setsum_right_distrib.

* Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
``rule'' method.

* Reimplemented methods "sat" and "satx", with several improvements:
goals no longer need to be stated as "<prems> ==> False", equivalences
(i.e. "=" on type bool) are handled, variable names of the form
"lit_<n>" are no longer reserved, significant speedup.

* Methods "sat" and "satx" can now replay MiniSat proof traces.
zChaff is still supported as well.

* 'inductive' and 'datatype': provide projections of mutual rules,
bundled as foo_bar.inducts;

* Library: moved theories Parity, GCD, Binomial, Infinite_Set to
Library.

* Library: moved theory Accessible_Part to main HOL.

* Library: added theory Coinductive_List of potentially infinite lists
as greatest fixed-point.

* Library: added theory AssocList which implements (finite) maps as
association lists.

* Method "evaluation" solves goals (i.e. a boolean expression)
efficiently by compiling it to ML.  The goal is "proved" (via an
oracle) if it evaluates to True.

* Linear arithmetic now splits certain operators (e.g. min, max, abs)
also when invoked by the simplifier.  This results in the Simplifier
being more powerful on arithmetic goals.  INCOMPATIBILITY.
Configuration option fast_arith_split_limit=0 recovers the old
behavior.

* Support for hex (0x20) and binary (0b1001) numerals.

* New method: reify eqs (t), where eqs are equations for an
interpretation I :: 'a list => 'b => 'c and t::'c is an optional
parameter, computes a term s::'b and a list xs::'a list and proves the
theorem I xs s = t. This is also known as reification or quoting. The
resulting theorem is applied to the subgoal to substitute t with I xs
s.  If t is omitted, the subgoal itself is reified.

* New method: reflection corr_thm eqs (t). The parameters eqs and (t)
are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
where f is supposed to be a computable function (in the sense of code
generattion). The method uses reify to compute s and xs as above then
applies corr_thm and uses normalization by evaluation to "prove" f s =
r and finally gets the theorem t = r, which is again applied to the
subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.

* Reflection: Automatic reification now handels binding, an example is
available in src/HOL/ex/ReflectionEx.thy

* HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
command 'statespace' that is similar to 'record', but introduces an
abstract specification based on the locale infrastructure instead of
HOL types.  This leads to extra flexibility in composing state spaces,
in particular multiple inheritance and renaming of components.


*** HOL-Complex ***

* Hyperreal: Functions root and sqrt are now defined on negative real
inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
Nonnegativity side conditions have been removed from many lemmas, so
that more subgoals may now be solved by simplification; potential
INCOMPATIBILITY.

* Real: new type classes formalize real normed vector spaces and
algebras, using new overloaded constants scaleR :: real => 'a => 'a
and norm :: 'a => real.

* Real: constant of_real :: real => 'a::real_algebra_1 injects from
reals into other types. The overloaded constant Reals :: 'a set is now
defined as range of_real; potential INCOMPATIBILITY.

* Real: proper support for ML code generation, including 'quickcheck'.
Reals are implemented as arbitrary precision rationals.

* Hyperreal: Several constants that previously worked only for the
reals have been generalized, so they now work over arbitrary vector
spaces. Type annotations may need to be added in some cases; potential
INCOMPATIBILITY.

  Infinitesimal  :: ('a::real_normed_vector) star set
  HFinite        :: ('a::real_normed_vector) star set
  HInfinite      :: ('a::real_normed_vector) star set
  approx         :: ('a::real_normed_vector) star => 'a star => bool
  monad          :: ('a::real_normed_vector) star => 'a star set
  galaxy         :: ('a::real_normed_vector) star => 'a star set
  (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  sgn            :: 'a::real_normed_vector => 'a
  exp            :: 'a::{recpower,real_normed_field,banach} => 'a

* Complex: Some complex-specific constants are now abbreviations for
overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
hnorm.  Other constants have been entirely removed in favor of the
polymorphic versions (INCOMPATIBILITY):

  approx        <-- capprox
  HFinite       <-- CFinite
  HInfinite     <-- CInfinite
  Infinitesimal <-- CInfinitesimal
  monad         <-- cmonad
  galaxy        <-- cgalaxy
  (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  (ns)deriv     <-- (ns)cderiv


*** HOL-Algebra ***

* Formalisation of ideals and the quotient construction over rings.

* Order and lattice theory no longer based on records.
INCOMPATIBILITY.

* Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
greatest_closed.  INCOMPATIBILITY.

* Method algebra is now set up via an attribute.  For examples see
Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
of algebraic structures.

* Renamed theory CRing to Ring.


*** HOL-Nominal ***

* Substantial, yet incomplete support for nominal datatypes (binding
structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
src/HOL/Nominal/Examples.  Prospective users should consult
http://isabelle.in.tum.de/nominal/


*** ML ***

* ML basics: just one true type int, which coincides with IntInf.int
(even on SML/NJ).

* ML within Isar: antiquotations allow to embed statically-checked
formal entities in the source, referring to the context available at
compile-time.  For example:

ML {* @{sort "{zero,one}"} *}
ML {* @{typ "'a => 'b"} *}
ML {* @{term "%x. x"} *}
ML {* @{prop "x == y"} *}
ML {* @{ctyp "'a => 'b"} *}
ML {* @{cterm "%x. x"} *}
ML {* @{cprop "x == y"} *}
ML {* @{thm asm_rl} *}
ML {* @{thms asm_rl} *}
ML {* @{type_name c} *}
ML {* @{type_syntax c} *}
ML {* @{const_name c} *}
ML {* @{const_syntax c} *}
ML {* @{context} *}
ML {* @{theory} *}
ML {* @{theory Pure} *}
ML {* @{theory_ref} *}
ML {* @{theory_ref Pure} *}
ML {* @{simpset} *}
ML {* @{claset} *}
ML {* @{clasimpset} *}

The same works for sources being ``used'' within an Isar context.

* ML in Isar: improved error reporting; extra verbosity with
ML_Context.trace enabled.

* Pure/General/table.ML: the join operations now works via exceptions
DUP/SAME instead of type option. This is simpler in simple cases, and
admits slightly more efficient complex applications.

* Pure: 'advanced' translation functions (parse_translation etc.) now
use Context.generic instead of just theory.

* Pure: datatype Context.generic joins theory/Proof.context and
provides some facilities for code that works in either kind of
context, notably GenericDataFun for uniform theory and proof data.

* Pure: simplified internal attribute type, which is now always
Context.generic * thm -> Context.generic * thm. Global (theory) vs.
local (Proof.context) attributes have been discontinued, while
minimizing code duplication. Thm.rule_attribute and
Thm.declaration_attribute build canonical attributes; see also structure
Context for further operations on Context.generic, notably
GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
declarations and definitions.

* Context data interfaces (Theory/Proof/GenericDataFun): removed
name/print, uninitialized data defaults to ad-hoc copy of empty value,
init only required for impure data. INCOMPATIBILITY: empty really need
to be empty (no dependencies on theory content!)

* Pure/kernel: consts certification ignores sort constraints given in
signature declarations. (This information is not relevant to the
logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
potential INCOMPATIBILITY.

* Pure: axiomatic type classes are now purely definitional, with
explicit proofs of class axioms and super class relations performed
internally. See Pure/axclass.ML for the main internal interfaces --
notably AxClass.define_class supercedes AxClass.add_axclass, and
AxClass.axiomatize_class/classrel/arity supersede
Sign.add_classes/classrel/arities.

* Pure/Isar: Args/Attrib parsers operate on Context.generic --
global/local versions on theory vs. Proof.context have been
discontinued; Attrib.syntax and Method.syntax have been adapted
accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
attributes, methods, etc.

* Pure: several functions of signature "... -> theory -> theory * ..."
have been reoriented to "... -> theory -> ... * theory" in order to
allow natural usage in combination with the ||>, ||>>, |-> and
fold_map combinators.

* Pure: official theorem names (closed derivations) and additional
comments (tags) are now strictly separate.  Name hints -- which are
maintained as tags -- may be attached any time without affecting the
derivation.

* Pure: primitive rule lift_rule now takes goal cterm instead of an
actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
achieve the old behaviour.

* Pure: the "Goal" constant is now called "prop", supporting a
slightly more general idea of ``protecting'' meta-level rule
statements.

* Pure: Logic.(un)varify only works in a global context, which is now
enforced instead of silently assumed.  INCOMPATIBILITY, may use
Logic.legacy_(un)varify as temporary workaround.

* Pure: structure Name provides scalable operations for generating
internal variable names, notably Name.variants etc.  This replaces
some popular functions from term.ML:

  Term.variant		->  Name.variant
  Term.variantlist	->  Name.variant_list
  Term.invent_names	->  Name.invent_list

Note that low-level renaming rarely occurs in new code -- operations
from structure Variable are used instead (see below).

* Pure: structure Variable provides fundamental operations for proper
treatment of fixed/schematic variables in a context.  For example,
Variable.import introduces fixes for schematics of given facts and
Variable.export reverses the effect (up to renaming) -- this replaces
various freeze_thaw operations.

* Pure: structure Goal provides simple interfaces for
init/conclude/finish and tactical prove operations (replacing former
Tactic.prove).  Goal.prove is the canonical way to prove results
within a given context; Goal.prove_global is a degraded version for
theory level goals, including a global Drule.standard.  Note that
OldGoals.prove_goalw_cterm has long been obsolete, since it is
ill-behaved in a local proof context (e.g. with local fixes/assumes or
in a locale context).

* Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
and type checking (Syntax.check_term etc.), with common combinations
(Syntax.read_term etc.). These supersede former Sign.read_term etc.
which are considered legacy and await removal.

* Pure/Syntax: generic interfaces for type unchecking
(Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
with common combinations (Syntax.pretty_term, Syntax.string_of_term
etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
available for convenience, but refer to the very same operations using
a mere theory instead of a full context.

* Isar: simplified treatment of user-level errors, using exception
ERROR of string uniformly.  Function error now merely raises ERROR,
without any side effect on output channels.  The Isar toplevel takes
care of proper display of ERROR exceptions.  ML code may use plain
handle/can/try; cat_error may be used to concatenate errors like this:

  ... handle ERROR msg => cat_error msg "..."

Toplevel ML code (run directly or through the Isar toplevel) may be
embedded into the Isar toplevel with exception display/debug like
this:

  Isar.toplevel (fn () => ...)

INCOMPATIBILITY, removed special transform_error facilities, removed
obsolete variants of user-level exceptions (ERROR_MESSAGE,
Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
-- use plain ERROR instead.

* Isar: theory setup now has type (theory -> theory), instead of a
list.  INCOMPATIBILITY, may use #> to compose setup functions.

* Isar: ML toplevel pretty printer for type Proof.context, subject to
ProofContext.debug/verbose flags.

* Isar: Toplevel.theory_to_proof admits transactions that modify the
theory before entering a proof state.  Transactions now always see a
quasi-functional intermediate checkpoint, both in interactive and
batch mode.

* Isar: simplified interfaces for outer syntax.  Renamed
OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
OuterSyntax.add_parsers -- this functionality is now included in
OuterSyntax.command etc.  INCOMPATIBILITY.

* Simplifier: the simpset of a running simplification process now
contains a proof context (cf. Simplifier.the_context), which is the
very context that the initial simpset has been retrieved from (by
simpset_of/local_simpset_of).  Consequently, all plug-in components
(solver, looper etc.) may depend on arbitrary proof data.

* Simplifier.inherit_context inherits the proof context (plus the
local bounds) of the current simplification process; any simproc
etc. that calls the Simplifier recursively should do this!  Removed
former Simplifier.inherit_bounds, which is already included here --
INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
specify an explicit context using Simplifier.context/theory_context.

* Simplifier/Classical Reasoner: more abstract interfaces
change_simpset/claset for modifying the simpset/claset reference of a
theory; raw versions simpset/claset_ref etc. have been discontinued --
INCOMPATIBILITY.

* Provers: more generic wrt. syntax of object-logics, avoid hardwired
"Trueprop" etc.


*** System ***

* settings: the default heap location within ISABELLE_HOME_USER now
includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
Isabelle installations.

* isabelle-process: option -S (secure mode) disables some critical
operations, notably runtime compilation and evaluation of ML source
code.

* Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.

* Support for parallel execution, using native multicore support of
Poly/ML 5.1.  The theory loader exploits parallelism when processing
independent theories, according to the given theory header
specifications. The maximum number of worker threads is specified via
usedir option -M or the "max-threads" setting in Proof General. A
speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
to 6 on a 8-core machine.  User-code needs to observe certain
guidelines for thread-safe programming, see appendix A in the Isar
Implementation manual.



New in Isabelle2005 (October 2005)
----------------------------------

*** General ***

* Theory headers: the new header syntax for Isar theories is

  theory <name>
  imports <theory1> ... <theoryN>
  uses <file1> ... <fileM>
  begin

where the 'uses' part is optional.  The previous syntax

  theory <name> = <theory1> + ... + <theoryN>:

will disappear in the next release.  Use isatool fixheaders to convert
existing theory files.  Note that there is no change in ancient
non-Isar theories now, but these will disappear soon.

* Theory loader: parent theories can now also be referred to via
relative and absolute paths.

* Command 'find_theorems' searches for a list of criteria instead of a
list of constants. Known criteria are: intro, elim, dest, name:string,
simp:term, and any term. Criteria can be preceded by '-' to select
theorems that do not match. Intro, elim, dest select theorems that
match the current goal, name:s selects theorems whose fully qualified
name contain s, and simp:term selects all simplification rules whose
lhs match term.  Any other term is interpreted as pattern and selects
all theorems matching the pattern. Available in ProofGeneral under
'ProofGeneral -> Find Theorems' or C-c C-f.  Example:

  C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."

prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
matching the current goal as introduction rule and not having "HOL."
in their name (i.e. not being defined in theory HOL).

* Command 'thms_containing' has been discontinued in favour of
'find_theorems'; INCOMPATIBILITY.

* Communication with Proof General is now 8bit clean, which means that
Unicode text in UTF-8 encoding may be used within theory texts (both
formal and informal parts).  Cf. option -U of the Isabelle Proof
General interface.  Here are some simple examples (cf. src/HOL/ex):

  http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  http://isabelle.in.tum.de/library/HOL/ex/Chinese.html

* Improved efficiency of the Simplifier and, to a lesser degree, the
Classical Reasoner.  Typical big applications run around 2 times
faster.


*** Document preparation ***

* Commands 'display_drafts' and 'print_drafts' perform simple output
of raw sources.  Only those symbols that do not require additional
LaTeX packages (depending on comments in isabellesym.sty) are
displayed properly, everything else is left verbatim.  isatool display
and isatool print are used as front ends (these are subject to the
DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).

* Command tags control specific markup of certain regions of text,
notably folding and hiding.  Predefined tags include "theory" (for
theory begin and end), "proof" for proof commands, and "ML" for
commands involving ML code; the additional tags "visible" and
"invisible" are unused by default.  Users may give explicit tag
specifications in the text, e.g. ''by %invisible (auto)''.  The
interpretation of tags is determined by the LaTeX job during document
preparation: see option -V of isatool usedir, or options -n and -t of
isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
\isadroptag.

Several document versions may be produced at the same time via isatool
usedir (the generated index.html will link all of them).  Typical
specifications include ''-V document=theory,proof,ML'' to present
theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
these parts without any formal replacement text.  The Isabelle site
default settings produce ''document'' and ''outline'' versions as
specified above.

* Several new antiquotations:

  @{term_type term} prints a term with its type annotated;

  @{typeof term} prints the type of a term;

  @{const const} is the same as @{term const}, but checks that the
  argument is a known logical constant;

  @{term_style style term} and @{thm_style style thm} print a term or
  theorem applying a "style" to it

  @{ML text}

Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
definitions, equations, inequations etc., 'concl' printing only the
conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
to print the specified premise.  TermStyle.add_style provides an ML
interface for introducing further styles.  See also the "LaTeX Sugar"
document practical applications.  The ML antiquotation prints
type-checked ML expressions verbatim.

* Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
and 'text' support optional locale specification '(in loc)', which
specifies the default context for interpreting antiquotations.  For
example: 'text (in lattice) {* @{thm inf_assoc}*}'.

* Option 'locale=NAME' of antiquotations specifies an alternative
context interpreting the subsequent argument.  For example: @{thm
[locale=lattice] inf_assoc}.

* Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
a proof context.

* Proper output of antiquotations for theory commands involving a
proof context (such as 'locale' or 'theorem (in loc) ...').

* Delimiters of outer tokens (string etc.) now produce separate LaTeX
macros (\isachardoublequoteopen, isachardoublequoteclose etc.).

* isatool usedir: new option -C (default true) controls whether option
-D should include a copy of the original document directory; -C false
prevents unwanted effects such as copying of administrative CVS data.


*** Pure ***

* Considerably improved version of 'constdefs' command.  Now performs
automatic type-inference of declared constants; additional support for
local structure declarations (cf. locales and HOL records), see also
isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
sequential dependencies of definitions within a single 'constdefs'
section; moreover, the declared name needs to be an identifier.  If
all fails, consider to fall back on 'consts' and 'defs' separately.

* Improved indexed syntax and implicit structures.  First of all,
indexed syntax provides a notational device for subscripted
application, using the new syntax \<^bsub>term\<^esub> for arbitrary
expressions.  Secondly, in a local context with structure
declarations, number indexes \<^sub>n or the empty index (default
number 1) refer to a certain fixed variable implicitly; option
show_structs controls printing of implicit structures.  Typical
applications of these concepts involve record types and locales.

* New command 'no_syntax' removes grammar declarations (and
translations) resulting from the given syntax specification, which is
interpreted in the same manner as for the 'syntax' command.

* 'Advanced' translation functions (parse_translation etc.) may depend
on the signature of the theory context being presently used for
parsing/printing, see also isar-ref manual.

* Improved 'oracle' command provides a type-safe interface to turn an
ML expression of type theory -> T -> term into a primitive rule of
type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
is already included here); see also FOL/ex/IffExample.thy;
INCOMPATIBILITY.

* axclass: name space prefix for class "c" is now "c_class" (was "c"
before); "cI" is no longer bound, use "c.intro" instead.
INCOMPATIBILITY.  This change avoids clashes of fact bindings for
axclasses vs. locales.

* Improved internal renaming of symbolic identifiers -- attach primes
instead of base 26 numbers.

* New flag show_question_marks controls printing of leading question
marks in schematic variable names.

* In schematic variable names, *any* symbol following \<^isub> or
\<^isup> is now treated as part of the base name.  For example, the
following works without printing of awkward ".0" indexes:

  lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
    by simp

* Inner syntax includes (*(*nested*) comments*).

* Pretty printer now supports unbreakable blocks, specified in mixfix
annotations as "(00...)".

* Clear separation of logical types and nonterminals, where the latter
may only occur in 'syntax' specifications or type abbreviations.
Before that distinction was only partially implemented via type class
"logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
exotic syntax specifications may require further adaption
(e.g. Cube/Cube.thy).

* Removed obsolete type class "logic", use the top sort {} instead.
Note that non-logical types should be declared as 'nonterminals'
rather than 'types'.  INCOMPATIBILITY for new object-logic
specifications.

* Attributes 'induct' and 'cases': type or set names may now be
locally fixed variables as well.

* Simplifier: can now control the depth to which conditional rewriting
is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
Limit.

* Simplifier: simplification procedures may now take the current
simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
interface), which is very useful for calling the Simplifier
recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
is gone -- use prems_of_ss on the simpset instead.  Moreover, the
low-level mk_simproc no longer applies Logic.varify internally, to
allow for use in a context of fixed variables.

* thin_tac now works even if the assumption being deleted contains !!
or ==>.  More generally, erule now works even if the major premise of
the elimination rule contains !! or ==>.

* Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.

* Reorganized bootstrapping of the Pure theories; CPure is now derived
from Pure, which contains all common declarations already.  Both
theories are defined via plain Isabelle/Isar .thy files.
INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
CPure.elim / CPure.dest attributes) now appear in the Pure name space;
use isatool fixcpure to adapt your theory and ML sources.

* New syntax 'name(i-j, i-, i, ...)' for referring to specific
selections of theorems in named facts via index ranges.

* 'print_theorems': in theory mode, really print the difference
wrt. the last state (works for interactive theory development only),
in proof mode print all local facts (cf. 'print_facts');

* 'hide': option '(open)' hides only base names.

* More efficient treatment of intermediate checkpoints in interactive
theory development.

* Code generator is now invoked via code_module (incremental code
generation) and code_library (modular code generation, ML structures
for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
must be quoted when used as identifiers.

* New 'value' command for reading, evaluating and printing terms using
the code generator.  INCOMPATIBILITY: command keyword 'value' must be
quoted when used as identifier.


*** Locales ***

* New commands for the interpretation of locale expressions in
theories (1), locales (2) and proof contexts (3).  These generate
proof obligations from the expression specification.  After the
obligations have been discharged, theorems of the expression are added
to the theory, target locale or proof context.  The synopsis of the
commands is a follows:

  (1) interpretation expr inst
  (2) interpretation target < expr
  (3) interpret expr inst

Interpretation in theories and proof contexts require a parameter
instantiation of terms from the current context.  This is applied to
specifications and theorems of the interpreted expression.
Interpretation in locales only permits parameter renaming through the
locale expression.  Interpretation is smart in that interpretations
that are active already do not occur in proof obligations, neither are
instantiated theorems stored in duplicate.  Use 'print_interps' to
inspect active interpretations of a particular locale.  For details,
see the Isar Reference manual.  Examples can be found in
HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.

INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
'interpret' instead.

* New context element 'constrains' for adding type constraints to
parameters.

* Context expressions: renaming of parameters with syntax
redeclaration.

* Locale declaration: 'includes' disallowed.

* Proper static binding of attribute syntax -- i.e. types / terms /
facts mentioned as arguments are always those of the locale definition
context, independently of the context of later invocations.  Moreover,
locale operations (renaming and type / term instantiation) are applied
to attribute arguments as expected.

INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
actual attributes; rare situations may require Attrib.attribute to
embed those attributes into Attrib.src that lack concrete syntax.
Attribute implementations need to cooperate properly with the static
binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
Attrib.XXX_thm etc. already do the right thing without further
intervention.  Only unusual applications -- such as "where" or "of"
(cf. src/Pure/Isar/attrib.ML), which process arguments depending both
on the context and the facts involved -- may have to assign parsed
values to argument tokens explicitly.

* Changed parameter management in theorem generation for long goal
statements with 'includes'.  INCOMPATIBILITY: produces a different
theorem statement in rare situations.

* Locale inspection command 'print_locale' omits notes elements.  Use
'print_locale!' to have them included in the output.


*** Provers ***

* Provers/hypsubst.ML: improved version of the subst method, for
single-step rewriting: it now works in bound variable contexts. New is
'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
rewrite a different subterm than the original subst method, which is
still available as 'simplesubst'.

* Provers/quasi.ML: new transitivity reasoners for transitivity only
and quasi orders.

* Provers/trancl.ML: new transitivity reasoner for transitive and
reflexive-transitive closure of relations.

* Provers/blast.ML: new reference depth_limit to make blast's depth
limit (previously hard-coded with a value of 20) user-definable.

* Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
is peformed already.  Object-logics merely need to finish their
initial simpset configuration as before.  INCOMPATIBILITY.


*** HOL ***

* Symbolic syntax of Hilbert Choice Operator is now as follows:

  syntax (epsilon)
    "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)

The symbol \<some> is displayed as the alternative epsilon of LaTeX
and x-symbol; use option '-m epsilon' to get it actually printed.
Moreover, the mathematically important symbolic identifier \<epsilon>
becomes available as variable, constant etc.  INCOMPATIBILITY,

* "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
support corresponding Isar calculations.

* "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
instead of ":".

* theory SetInterval: changed the syntax for open intervals:

  Old       New
  {..n(}    {..<n}
  {)n..}    {n<..}
  {m..n(}   {m..<n}
  {)m..n}   {m<..n}
  {)m..n(}  {m<..<n}

The old syntax is still supported but will disappear in the next
release.  For conversion use the following Emacs search and replace
patterns (these are not perfect but work quite well):

  {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  \.\.\([^(}]*\)(}  ->  \.\.<\1}

* Theory Commutative_Ring (in Library): method comm_ring for proving
equalities in commutative rings; method 'algebra' provides a generic
interface.

* Theory Finite_Set: changed the syntax for 'setsum', summation over
finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
be a tuple pattern.

Some new syntax forms are available:

  "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"

The latter form "\<Sum>x < k. e" used to be based on a separate
function "Summation", which has been discontinued.

* theory Finite_Set: in structured induction proofs, the insert case
is now 'case (insert x F)' instead of the old counterintuitive 'case
(insert F x)'.

* The 'refute' command has been extended to support a much larger
fragment of HOL, including axiomatic type classes, constdefs and
typedefs, inductive datatypes and recursion.

* New tactics 'sat' and 'satx' to prove propositional tautologies.
Requires zChaff with proof generation to be installed.  See
HOL/ex/SAT_Examples.thy for examples.

* Datatype induction via method 'induct' now preserves the name of the
induction variable. For example, when proving P(xs::'a list) by
induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
in unstructured proof scripts.

* Reworked implementation of records.  Improved scalability for
records with many fields, avoiding performance problems for type
inference. Records are no longer composed of nested field types, but
of nested extension types. Therefore the record type only grows linear
in the number of extensions and not in the number of fields.  The
top-level (users) view on records is preserved.  Potential
INCOMPATIBILITY only in strange cases, where the theory depends on the
old record representation. The type generated for a record is called
<record_name>_ext_type.

Flag record_quick_and_dirty_sensitive can be enabled to skip the
proofs triggered by a record definition or a simproc (if
quick_and_dirty is enabled).  Definitions of large records can take
quite long.

New simproc record_upd_simproc for simplification of multiple record
updates enabled by default.  Moreover, trivial updates are also
removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
occasionally, since simplification is more powerful by default.

* typedef: proper support for polymorphic sets, which contain extra
type-variables in the term.

* Simplifier: automatically reasons about transitivity chains
involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
old proofs break occasionally as simplification may now solve more
goals than previously.

* Simplifier: converts x <= y into x = y if assumption y <= x is
present.  Works for all partial orders (class "order"), in particular
numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
just like y <= x.

* Simplifier: new simproc for "let x = a in f x".  If a is a free or
bound variable or a constant then the let is unfolded.  Otherwise
first a is simplified to b, and then f b is simplified to g. If
possible we abstract b from g arriving at "let x = b in h x",
otherwise we unfold the let and arrive at g.  The simproc can be
enabled/disabled by the reference use_let_simproc.  Potential
INCOMPATIBILITY since simplification is more powerful by default.

* Classical reasoning: the meson method now accepts theorems as arguments.