Isabelle NEWS -- history user-relevant changes

 ==============================================

 New in this Isabelle version

 ----------------------------

 *** General ***

 * 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", "if", "fun") are

 now keywords.  INCOMPATIBILITY, use double quotes.

 * 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': support "*" wildcard in "name:" criterion.

 * 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.

 *** Document preparation ***

 * Added antiquotations @{ML_type text} and @{ML_struct text} which

 check the given source text as ML type/structure, printing verbatim.

 *** Pure ***

 * class_package.ML offers a combination of axclasses and locales to

 achieve Haskell-like type classes in Isabelle. See

 HOL/ex/Classpackage.thy for examples.

 * Yet another code generator framework allows to generate executable

 code for ML and Haskell (including "class"es). A short usage sketch:

     internal compilation:

         code_gen <list of constants (term syntax)> (SML -)

     writing SML code to a file:

         code_gen <list of constants (term syntax)> (SML <filename>)

     writing Haskell code to a bunch of files:

         code_gen <list of constants (term syntax)> (Haskell <filename>)

 Reasonable default setup of framework in HOL/Main.

 See HOL/ex/Code*.thy for examples.

 Theorem attributs for selecting and transforming function equations theorems:

     [code fun]:       select a theorem as function equation for a specific constant

     [code nofun]:     deselect a theorem as function equation for a specific constant

     [code inline]:    select an equation theorem for unfolding (inlining) in place

     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place

 User-defined serializations (target in {SML, 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>}+}?

 For code_instance and code_class, target SML is silently ignored.

 See HOL theories and HOL/ex/Code*.thy for usage examples.

 * 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".

 * 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 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: '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.

 * Isar/locales: 'const_syntax' provides a robust interface to the

 'syntax' primitive that also works in a locale context.  Type

 declaration and internal syntactic representation of given constants

 retrieved from the 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"

     "g x = f x x"

   abbreviation

     neq  (infix "=!=" 50)

     "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

 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.

 Concrete syntax is attached to specified constants in internal form,

 independently of name spaces.  The parse tree representation is

 slightly different -- use 'const_syntax' instead of raw 'syntax', and

 'translations' with explicit "CONST" markup to accommodate this.

 * Isar/locales: improved parameter handling:

 - use of locales "var" and "struct" no longer necessary;

 - parameter renamings are no longer required to be injective.

   This enables, for example, to define a locale for endomorphisms thus:

   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.

 * Provers/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).  The subsequent proof patterns illustrate advanced

 techniques of natural induction; general datatypes and inductive sets

 work analogously (see also src/HOL/Lambda for realistic examples).

 (1) This is how to ``strengthen'' an inductive goal wrt. certain

 parameters:

   lemma

     fixes n :: nat and x :: 'a

     assumes a: "A n x"

     shows "P n x"

     using a                     -- {* make induct insert fact a *}

   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}

     case 0

     show ?case sorry

   next

     case (Suc n)

     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}

     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}

     show ?case sorry

   qed

 (2) This is how to perform induction over ``expressions of a certain

 form'', using a locally defined inductive parameter n == "a x"

 together with strengthening (the latter is usually required to get

 sufficiently flexible induction hypotheses):

   lemma

     fixes a :: "'a => nat"

     assumes a: "A (a x)"

     shows "P (a x)"

     using a

   proof (induct n == "a x" arbitrary: x)

     ...

 See also HOL/Isar_examples/Puzzle.thy for an application of the this

 particular technique.

 (3) This is how to perform existential reasoning ('obtains' or

 'obtain') by induction, while avoiding explicit object-logic

 encodings:

   lemma

     fixes n :: nat

     obtains x :: 'a where "P n x" and "Q n x"

   proof (induct n arbitrary: thesis)

     case 0

     obtain x where "P 0 x" and "Q 0 x" sorry

     then show thesis by (rule 0)

   next

     case (Suc n)

     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)

     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry

     then show thesis by (rule Suc.prems)

   qed

 Here the 'arbitrary: thesis' specification essentially modifies the

 scope of the formal thesis parameter, in order to the get the whole

 existence statement through the induction as expected.

 * Provers/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 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 type: foo bar)

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

 new format.

 * Provers/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.  For example:

   lemma

     fixes n :: nat

     shows "P n" and "Q n"

   proof (induct n)

     case 0 case 1

     show "P 0" sorry

   next

     case 0 case 2

     show "Q 0" sorry

   next

     case (Suc n) case 1

     note `P n` and `Q n`

     show "P (Suc n)" sorry

   next

     case (Suc n) case 2

     note `P n` and `Q n`

     show "Q (Suc n)" sorry

   qed

 The split into subcases may be deferred as follows -- this is

 particularly relevant for goal statements with local premises.

   lemma

     fixes n :: nat

     shows "A n ==> P n" and "B n ==> Q n"

   proof (induct n)

     case 0

     {

       case 1

       note `A 0`

       show "P 0" sorry

     next

       case 2

       note `B 0`

       show "Q 0" sorry

     }

   next

     case (Suc n)

     note `A n ==> P n` and `B n ==> Q n`

     {

       case 1

       note `A (Suc n)`

       show "P (Suc n)" sorry

     next

       case 2

       note `B (Suc n)`

       show "Q (Suc n)" sorry

     }

   qed

 If simultaneous goals are to be used with mutual rules, the statement

 needs to be structured carefully as a two-level conjunction, using

 lists of propositions separated by 'and':

   lemma

     shows "a : A ==> P1 a"

           "a : A ==> P2 a"

       and "b : B ==> Q1 b"

           "b : B ==> Q2 b"

           "b : B ==> Q3 b"

   proof (induct set: A B)

 * Provers/induct: support coinduction as well.  See

 src/HOL/Library/Coinductive_List.thy for various examples.

 * 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 entities with internal name

 (trailing "_") by default; use '!' option for full details.

 *** HOL ***

 * Renamed constants in HOL.thy:

     0      ~> HOL.zero

     1      ~> HOL.one

 INCOMPATIBILITY: ML code directly refering to constant names may need adaption

 This in general only affects hand-written proof tactics, simprocs and so on.

 * New theory OperationalEquality providing class 'eq' with constant 'eq',

 allowing for code generation with polymorphic equality.

 * 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 HOL/Integ/IntArith.thy for an example setup.

 * New top level command 'normal_form' computes the normal form of a term

 that may contain free variables. For example 'normal_form "rev[a,b,c]"'

 prints '[b,c,a]'. This command is suitable for heavy-duty computations

 because the functions are compiled to ML first.

 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as

 an identifier.

 * 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).

 * Renamed constants in HOL.thy and Orderings.thy:

     op +   ~> HOL.plus

     op -   ~> HOL.minus

     uminus ~> HOL.uminus

     op *   ~> HOL.times

     op <   ~> Orderings.less

     op <=  ~> Orderings.less_eq

 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.

 * "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_simproc").  For backward

 compatibility this can be disabled by ML "reset use_neq_simproc".

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

 * Theorem Cons_eq_map_conv no longer has attribute `simp'.

 * Theorem setsum_mult renamed to setsum_right_distrib.

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

 'rule' method.

 * Tactics 'sat' and 'satx' reimplemented, 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.

 * Tactics '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: theory Infinite_Set has been moved to the library.

 * Library: theory Accessible_Part has been move 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.

 * New proof method "evaluation" for efficiently solving a goal (i.e. a

 boolean expression) by compiling it to ML. The goal is "proved" (via

 the oracle "Evaluation") 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.  INCOMPATIBILTY.  Set

 fast_arith_split_limit to 0 to obtain 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 HOL/ex/ReflectionEx.thy.

 * Reflection: Automatic refification now handels binding, an example

 is available in HOL/ex/ReflectionEx.thy

 *** HOL-Algebra ***

 * Method algebra is now set up via an attribute.  For examples see CRing.thy.

   INCOMPATIBILITY: the method is now weaker on combinations of algebraic

   structures.

 * Formalisation of ideals and the quotient construction over rings, contributed

   by Stephan Hohe.

 * Renamed `CRing.thy' to `Ring.thy'.  INCOMPATIBILITY.

 *** HOL-Complex ***

 * Theory Real: new method ferrack implements quantifier elimination

 for linear arithmetic over the reals. The quantifier elimination

 feature is used only for decision, for compatibility with arith. This

 means a goal is either solved or left unchanged, no simplification.

 *** ML ***

 * Pure/library:

 infixes ins ins_string ins_int have been abandoned in favour of insert.

 INCOMPATIBILITY: rewrite "x ins(_...) xs" to "insert (op =) x xs"

 * Pure/General/susp.ML:

 New module for delayed evaluations.

 * Pure/library:

 Semantically identical functions "equal_list" and "eq_list" have been

 unified to "eq_list".

 * Pure/library:

   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list

   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd

 The semantics of "burrow" is: "take a function with *simulatanously*

 transforms a list of value, and apply it *simulatanously* to a list of

 list of values of the appropriate type". Confer this with "map" which

 would *not* apply its argument function simulatanously but in

 sequence. "fold_burrow" has an additional context.

 Both actually avoid the usage of "unflat" since they hide away

 "unflat" from the user.

 * Pure/library: functions map2 and fold2 with curried syntax for

 simultanous mapping and folding:

     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list

     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c

 * Pure/library: indexed lists - some functions in the Isabelle library

 treating lists over 'a as finite mappings from [0...n] to 'a have been

 given more convenient names and signatures reminiscent of similar

 functions for alists, tables, etc:

   val nth: 'a list -> int -> 'a 

   val nth_update: int * 'a -> 'a list -> 'a list

   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list

   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b

 Note that fold_index starts counting at index 0, not 1 like foldln

 used to.

 * Pure/library: general ``divide_and_conquer'' combinator on lists.

 * Pure/General/name_mangler.ML provides a functor for generic name

 mangling (bijective mapping from any expression values to strings).

 * Pure/General/rat.ML implements rational numbers.

 * 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: 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: 'advanced' translation functions (parse_translation etc.) now

 use Context.generic instead of just theory.

 * 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.

 * Pure/kernel: consts certification ignores sort constraints given in

 signature declarations.  (This information is not relevant to the

 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.

 * 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 supercede

 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: 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  (*canonical argument order*)

   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).

 * 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: installed 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.

 * 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.

 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.

 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background

 jobs to provide advice on the provability of subgoals.

 * Theory OrderedGroup and Ring_and_Field: various additions and

 improvements to faciliate calculations involving equalities and

 inequalities.

 The following theorems have been eliminated or modified

 (INCOMPATIBILITY):

   abs_eq             now named abs_of_nonneg

   abs_of_ge_0        now named abs_of_nonneg

   abs_minus_eq       now named abs_of_nonpos

   imp_abs_id         now named abs_of_nonneg

   imp_abs_neg_id     now named abs_of_nonpos

   mult_pos           now named mult_pos_pos

   mult_pos_le        now named mult_nonneg_nonneg

   mult_pos_neg_le    now named mult_nonneg_nonpos

   mult_pos_neg2_le   now named mult_nonneg_nonpos2

   mult_neg           now named mult_neg_neg

   mult_neg_le        now named mult_nonpos_nonpos

 * Theory Parity: added rules for simplifying exponents.

 * Theory List:

 The following theorems have been eliminated or modified

 (INCOMPATIBILITY):

   list_all_Nil       now named list_all.simps(1)

   list_all_Cons      now named list_all.simps(2)

   list_all_conv      now named list_all_iff

   set_mem_eq         now named mem_iff

 * Theories SetsAndFunctions and BigO (see HOL/Library) support

 asymptotic "big O" calculations.  See the notes in BigO.thy.

 *** HOL-Complex ***

 * Theory RealDef: better support for embedding natural numbers and

 integers in the reals.

 The following theorems have been eliminated or modified

 (INCOMPATIBILITY):

   exp_ge_add_one_self  now requires no hypotheses

   real_of_int_add      reversed direction of equality (use [symmetric])

   real_of_int_minus    reversed direction of equality (use [symmetric])

   real_of_int_diff     reversed direction of equality (use [symmetric])

   real_of_int_mult     reversed direction of equality (use [symmetric])

 * Theory RComplete: expanded support for floor and ceiling functions.

 * Theory Ln is new, with properties of the natural logarithm

 * Hyperreal: There is a new type constructor "star" for making

 nonstandard types.  The old type names are now type synonyms:

   hypreal = real star

   hypnat = nat star

   hcomplex = complex star

 * Hyperreal: Many groups of similarly-defined constants have been

 replaced by polymorphic versions (INCOMPATIBILITY):

   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex

   starset      <-- starsetNat, starsetC

   *s*          <-- *sNat*, *sc*

   starset_n    <-- starsetNat_n, starsetC_n

   *sn*         <-- *sNatn*, *scn*

   InternalSets <-- InternalNatSets, InternalCSets

   starfun      <-- starfun{Nat,Nat2,C,RC,CR}

   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*

   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n

   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*

   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs

 * Hyperreal: Many type-specific theorems have been removed in favor of

 theorems specific to various axiomatic type classes (INCOMPATIBILITY):

   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute

   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs

   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left

   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right

   right_minus <-- hypreal_add_minus

   left_minus <-- {hypreal,hcomplex}_add_minus_left

   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute

   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc

   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left

   mult_1_right <-- hcomplex_mult_one_right

   mult_zero_left <-- hcomplex_mult_zero_left

   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib

   right_distrib <-- hypnat_add_mult_distrib2

   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one

   right_inverse <-- hypreal_mult_inverse

   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left

   order_refl <-- {hypreal,hypnat}_le_refl

   order_trans <-- {hypreal,hypnat}_le_trans

   order_antisym <-- {hypreal,hypnat}_le_anti_sym

   order_less_le <-- {hypreal,hypnat}_less_le

   linorder_linear <-- {hypreal,hypnat}_le_linear

   add_left_mono <-- {hypreal,hypnat}_add_left_mono

   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2

   add_nonneg_nonneg <-- hypreal_le_add_order

 * Hyperreal: Separate theorems having to do with type-specific

 versions of constants have been merged into theorems that apply to the

 new polymorphic constants (INCOMPATIBILITY):

   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set

   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set

   STAR_Un <-- {STAR,NatStar,STARC}_Un

   STAR_Int <-- {STAR,NatStar,STARC}_Int

   STAR_Compl <-- {STAR,NatStar,STARC}_Compl

   STAR_subset <-- {STAR,NatStar,STARC}_subset

   STAR_mem <-- {STAR,NatStar,STARC}_mem

   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl

   STAR_diff <-- {STAR,STARC}_diff

   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,

     STARC_hcomplex_of_complex}_image_subset

   starset_n_Un <-- starset{Nat,C}_n_Un

   starset_n_Int <-- starset{Nat,C}_n_Int

   starset_n_Compl <-- starset{Nat,C}_n_Compl

   starset_n_diff <-- starset{Nat,C}_n_diff

   InternalSets_Un <-- Internal{Nat,C}Sets_Un

   InternalSets_Int <-- Internal{Nat,C}Sets_Int

   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl

   InternalSets_diff <-- Internal{Nat,C}Sets_diff

   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff

   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n

   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq

   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}

   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}

   starfun <-- starfun{Nat,Nat2,C,RC,CR}

   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult

   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add

   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus

   starfun_diff <-- starfun{C,RC,CR}_diff

   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o

   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2

   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun

   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse

   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq

   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff

   starfun_Id <-- starfunC_Id

   starfun_approx <-- starfun{Nat,CR}_approx

   starfun_capprox <-- starfun{C,RC}_capprox

   starfun_abs <-- starfunNat_rabs

   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel

   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2

   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox

   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox

   starfun_add_capprox <-- starfun{C,RC}_add_capprox

   starfun_add_approx <-- starfunCR_add_approx

   starfun_inverse_inverse <-- starfunC_inverse_inverse

   starfun_divide <-- starfun{C,CR,RC}_divide

   starfun_n <-- starfun{Nat,C}_n

   starfun_n_mult <-- starfun{Nat,C}_n_mult

   starfun_n_add <-- starfun{Nat,C}_n_add

   starfun_n_add_minus <-- starfunNat_n_add_minus

   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun

   starfun_n_minus <-- starfun{Nat,C}_n_minus

   starfun_n_eq <-- starfun{Nat,C}_n_eq

   star_n_add <-- {hypreal,hypnat,hcomplex}_add

   star_n_minus <-- {hypreal,hcomplex}_minus

   star_n_diff <-- {hypreal,hcomplex}_diff

   star_n_mult <-- {hypreal,hcomplex}_mult

   star_n_inverse <-- {hypreal,hcomplex}_inverse

   star_n_le <-- {hypreal,hypnat}_le

   star_n_less <-- {hypreal,hypnat}_less

   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num

   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num

   star_n_abs <-- hypreal_hrabs

   star_n_divide <-- hcomplex_divide

   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add

   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus

   star_of_diff <-- hypreal_of_real_diff

   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult

   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one

   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero

   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff

   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff

   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff

   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse

   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide

   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat

   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int

   star_of_number_of <-- {hypreal,hcomplex}_number_of

   star_of_number_less <-- number_of_less_hypreal_of_real_iff

   star_of_number_le <-- number_of_le_hypreal_of_real_iff

   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff

   star_of_less_number <-- hypreal_of_real_less_number_of_iff

   star_of_le_number <-- hypreal_of_real_le_number_of_iff

   star_of_power <-- hypreal_of_real_power

   star_of_eq_0 <-- hcomplex_of_complex_zero_iff

 * Hyperreal: new method "transfer" that implements the transfer

 principle of nonstandard analysis. With a subgoal that mentions

 nonstandard types like "'a star", the command "apply transfer"

 replaces it with an equivalent one that mentions only standard types.

 To be successful, all free variables must have standard types; non-

 standard variables must have explicit universal quantifiers.

 * Hyperreal: A theory of Taylor series.

 *** HOLCF ***

 * Discontinued special version of 'constdefs' (which used to support

 continuous functions) in favor of the general Pure one with full

 type-inference.

 * New simplification procedure for solving continuity conditions; it

 is much faster on terms with many nested lambda abstractions (cubic

 instead of exponential time).

 * New syntax for domain package: selector names are now optional.

 Parentheses should be omitted unless argument is lazy, for example:

   domain 'a stream = cons "'a" (lazy "'a stream")

 * New command 'fixrec' for defining recursive functions with pattern

 matching; defining multiple functions with mutual recursion is also

 supported.  Patterns may include the constants cpair, spair, up, sinl,

 sinr, or any data constructor defined by the domain package. The given

 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for

 syntax and examples.

 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes

 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,

 but the proof obligation additionally includes an admissibility

 requirement. The packages generate instances of class cpo or pcpo,

 with continuity and strictness theorems for Rep and Abs.

 * HOLCF: Many theorems have been renamed according to a more standard naming

 scheme (INCOMPATIBILITY):

   foo_inject:  "foo$x = foo$y ==> x = y"

   foo_eq:      "(foo$x = foo$y) = (x = y)"

   foo_less:    "(foo$x << foo$y) = (x << y)"

   foo_strict:  "foo$UU = UU"

   foo_defined: "... ==> foo$x ~= UU"

   foo_defined_iff: "(foo$x = UU) = (x = UU)"

 *** ZF ***

 * ZF/ex: theories Group and Ring provide examples in abstract algebra,

 including the First Isomorphism Theorem (on quotienting by the kernel

 of a homomorphism).

 * ZF/Simplifier: install second copy of type solver that actually

 makes use of TC rules declared to Isar proof contexts (or locales);

 the old version is still required for ML proof scripts.

 *** Cube ***

 * Converted to Isar theory format; use locales instead of axiomatic

 theories.

 *** ML ***

 * Pure/library.ML no longer defines its own option datatype, but uses

 that of the SML basis, which has constructors NONE and SOME instead of

 None and Some, as well as exception Option.Option instead of OPTION.

 The functions the, if_none, is_some, is_none have been adapted

 accordingly, while Option.map replaces apsome.

 * Pure/library.ML: the exception LIST has been given up in favour of

 the standard exceptions Empty and Subscript, as well as

 Library.UnequalLengths.  Function like Library.hd and Library.tl are

 superceded by the standard hd and tl functions etc.

 A number of basic list functions are no longer exported to the ML

 toplevel, as they are variants of predefined functions.  The following

 suggests how one can translate existing code:

     rev_append xs ys = List.revAppend (xs, ys)

     nth_elem (i, xs) = List.nth (xs, i)

     last_elem xs = List.last xs

     flat xss = List.concat xss

     seq fs = List.app fs

     partition P xs = List.partition P xs

     mapfilter f xs = List.mapPartial f xs

 * Pure/library.ML: several combinators for linear functional

 transformations, notably reverse application and composition:

   x |> f                f #> g

   (x, y) |-> f          f #-> g

 * Pure/library.ML: introduced/changed precedence of infix operators:

   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;

   infix 2 ?;

   infix 3 o oo ooo oooo;

   infix 4 ~~ upto downto;

 Maybe INCOMPATIBILITY when any of those is used in conjunction with other

 infix operators.

 * Pure/library.ML: natural list combinators fold, fold_rev, and

 fold_map support linear functional transformations and nesting.  For

 example:

   fold f [x1, ..., xN] y =

     y |> f x1 |> ... |> f xN

   (fold o fold) f [xs1, ..., xsN] y =

     y |> fold f xs1 |> ... |> fold f xsN

   fold f [x1, ..., xN] =

     f x1 #> ... #> f xN

   (fold o fold) f [xs1, ..., xsN] =

     fold f xs1 #> ... #> fold f xsN

 * Pure/library.ML: the following selectors on type 'a option are

 available:

   the:               'a option -> 'a  (*partial*)

   these:             'a option -> 'a  where 'a = 'b list

   the_default: 'a -> 'a option -> 'a

   the_list:          'a option -> 'a list

 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides

 basic operations for association lists, following natural argument

 order; moreover the explicit equality predicate passed here avoids

 potentially expensive polymorphic runtime equality checks.

 The old functions may be expressed as follows:

   assoc = uncurry (AList.lookup (op =))

   assocs = these oo AList.lookup (op =)

   overwrite = uncurry (AList.update (op =)) o swap

 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides

   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list

   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list

 replacing make_keylist and keyfilter (occassionally used)

 Naive rewrites:

   make_keylist = AList.make

   keyfilter = AList.find (op =)

 * eq_fst and eq_snd now take explicit equality parameter, thus

   avoiding eqtypes. Naive rewrites:

     eq_fst = eq_fst (op =)

     eq_snd = eq_snd (op =)

 * Removed deprecated apl and apr (rarely used).

   Naive rewrites:

     apl (n, op) =>>= curry op n

     apr (op, m) =>>= fn n => op (n, m)

 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)

 provides a reasonably efficient light-weight implementation of sets as

 lists.

 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a

 few new operations; existing lookup and update are now curried to

 follow natural argument order (for use with fold etc.);

 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.

 * Pure/General: output via the Isabelle channels of

 writeln/warning/error etc. is now passed through Output.output, with a

 hook for arbitrary transformations depending on the print_mode

 (cf. Output.add_mode -- the first active mode that provides a output

 function wins).  Already formatted output may be embedded into further

 text via Output.raw; the result of Pretty.string_of/str_of and derived

 functions (string_of_term/cterm/thm etc.) is already marked raw to

 accommodate easy composition of diagnostic messages etc.  Programmers

 rarely need to care about Output.output or Output.raw at all, with

 some notable exceptions: Output.output is required when bypassing the

 standard channels (writeln etc.), or in token translations to produce

 properly formatted results; Output.raw is required when capturing

 already output material that will eventually be presented to the user

 a second time.  For the default print mode, both Output.output and

 Output.raw have no effect.

 * Pure/General: Output.time_accumulator NAME creates an operator ('a

 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the

 cumulative results are displayed at the end of a batch session.

 * Pure/General: File.sysify_path and File.quote_sysify path have been

 replaced by File.platform_path and File.shell_path (with appropriate

 hooks).  This provides a clean interface for unusual systems where the

 internal and external process view of file names are different.

 * Pure: more efficient orders for basic syntactic entities: added

 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord

 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is

 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast

 orders now -- potential INCOMPATIBILITY for code that depends on a

 particular order for Symtab.keys, Symtab.dest, etc. (consider using

 Library.sort_strings on result).

 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,

 fold_types traverse types/terms from left to right, observing natural

 argument order.  Supercedes previous foldl_XXX versions, add_frees,

 add_vars etc. have been adapted as well: INCOMPATIBILITY.

 * Pure: name spaces have been refined, with significant changes of the

 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)

 to extern(_table).  The plain name entry path is superceded by a

 general 'naming' context, which also includes the 'policy' to produce

 a fully qualified name and external accesses of a fully qualified

 name; NameSpace.extend is superceded by context dependent

 Sign.declare_name.  Several theory and proof context operations modify

 the naming context.  Especially note Theory.restore_naming and

 ProofContext.restore_naming to get back to a sane state; note that

 Theory.add_path is no longer sufficient to recover from

 Theory.absolute_path in particular.

 * Pure: new flags short_names (default false) and unique_names

 (default true) for controlling output of qualified names.  If

 short_names is set, names are printed unqualified.  If unique_names is

 reset, the name prefix is reduced to the minimum required to achieve

 the original result when interning again, even if there is an overlap

 with earlier declarations.

 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is

 now 'extend', and 'merge' gets an additional Pretty.pp argument

 (useful for printing error messages).  INCOMPATIBILITY.

 * Pure: major reorganization of the theory context.  Type Sign.sg and

 Theory.theory are now identified, referring to the universal

 Context.theory (see Pure/context.ML).  Actual signature and theory

 content is managed as theory data.  The old code and interfaces were

 spread over many files and structures; the new arrangement introduces

 considerable INCOMPATIBILITY to gain more clarity:

   Context -- theory management operations (name, identity, inclusion,

     parents, ancestors, merge, etc.), plus generic theory data;

   Sign -- logical signature and syntax operations (declaring consts,

     types, etc.), plus certify/read for common entities;

   Theory -- logical theory operations (stating axioms, definitions,

     oracles), plus a copy of logical signature operations (consts,

     types, etc.); also a few basic management operations (Theory.copy,

     Theory.merge, etc.)

 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm

 etc.) as well as the sign field in Thm.rep_thm etc. have been retained

 for convenience -- they merely return the theory.

 * Pure: type Type.tsig is superceded by theory in most interfaces.

 * Pure: the Isar proof context type is already defined early in Pure

 as Context.proof (note that ProofContext.context and Proof.context are

 aliases, where the latter is the preferred name).  This enables other

 Isabelle components to refer to that type even before Isar is present.

 * Pure/sign/theory: discontinued named name spaces (i.e. classK,

 typeK, constK, axiomK, oracleK), but provide explicit operations for

 any of these kinds.  For example, Sign.intern typeK is now

 Sign.intern_type, Theory.hide_space Sign.typeK is now

 Theory.hide_types.  Also note that former

 Theory.hide_classes/types/consts are now

 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions

 internalize their arguments!  INCOMPATIBILITY.

 * Pure: get_thm interface (of PureThy and ProofContext) expects

 datatype thmref (with constructors Name and NameSelection) instead of

 plain string -- INCOMPATIBILITY;

 * Pure: cases produced by proof methods specify options, where NONE

 means to remove case bindings -- INCOMPATIBILITY in

 (RAW_)METHOD_CASES.

 * Pure: the following operations retrieve axioms or theorems from a

 theory node or theory hierarchy, respectively:

   Theory.axioms_of: theory -> (string * term) list

   Theory.all_axioms_of: theory -> (string * term) list

   PureThy.thms_of: theory -> (string * thm) list

   PureThy.all_thms_of: theory -> (string * thm) list

 * Pure: print_tac now outputs the goal through the trace channel.

 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.

 Reference Toplevel.debug (default false) controls detailed printing

 and tracing of low-level exceptions; Toplevel.profiling (default 0)

 controls execution profiling -- set to 1 for time and 2 for space

 (both increase the runtime).

 * Isar session: The initial use of ROOT.ML is now always timed,

 i.e. the log will show the actual process times, in contrast to the

 elapsed wall-clock time that the outer shell wrapper produces.

 * Simplifier: improved handling of bound variables (nameless

 representation, avoid allocating new strings).  Simprocs that invoke

 the Simplifier recursively should use Simplifier.inherit_bounds to

 avoid local name clashes.  Failure to do so produces warnings

 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds

 for further details.

 * ML functions legacy_bindings and use_legacy_bindings produce ML fact

 bindings for all theorems stored within a given theory; this may help

 in porting non-Isar theories to Isar ones, while keeping ML proof

 scripts for the time being.

 * ML operator HTML.with_charset specifies the charset begin used for

 generated HTML files.  For example:

   HTML.with_charset "utf-8" use_thy "Hebrew";

   HTML.with_charset "utf-8" use_thy "Chinese";

 *** System ***

 * Allow symlinks to all proper Isabelle executables (Isabelle,

 isabelle, isatool etc.).

 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for

 isatool doc, isatool mkdir, display_drafts etc.).

 * isatool usedir: option -f allows specification of the ML file to be

 used by Isabelle; default is ROOT.ML.

 * New isatool version outputs the version identifier of the Isabelle

 distribution being used.

 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format

 (containing Boolean satisfiability problems) into Isabelle/HOL

 theories.

 New in Isabelle2004 (April 2004)

 --------------------------------

 *** General ***

 * Provers/order.ML:  new efficient reasoner for partial and linear orders.

   Replaces linorder.ML.

 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic

   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler

   (\<a>...\<z>), are now considered normal letters, and can therefore

   be used anywhere where an ASCII letter (a...zA...Z) has until

   now. COMPATIBILITY: This obviously changes the parsing of some

   terms, especially where a symbol has been used as a binder, say

   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed

   as an identifier.  Fix it by inserting a space around former

   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in

   existing theory and ML files.

 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.

 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now

   allowed in identifiers. Similar to Greek letters \<^isub> is now considered

   a normal (but invisible) letter. For multiple letter subscripts repeat

   \<^isub> like this: x\<^isub>1\<^isub>2.

 * Pure: There are now sub-/superscripts that can span more than one

   character. Text between \<^bsub> and \<^esub> is set in subscript in

   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in

   superscript. The new control characters are not identifier parts.

 * Pure: Control-symbols of the form \<^raw:...> will literally print the

   content of "..." to the latex file instead of \isacntrl... . The "..."

   may consist of any printable characters excluding the end bracket >.

 * Pure: Using new Isar command "finalconsts" (or the ML functions

   Theory.add_finals or Theory.add_finals_i) it is now possible to

   declare constants "final", which prevents their being given a definition

   later.  It is useful for constants whose behaviour is fixed axiomatically

   rather than definitionally, such as the meta-logic connectives.

 * Pure: 'instance' now handles general arities with general sorts

   (i.e. intersections of classes),

 * Presentation: generated HTML now uses a CSS style sheet to make layout

   (somewhat) independent of content. It is copied from lib/html/isabelle.css.

   It can be changed to alter the colors/layout of generated pages.

 *** Isar ***

 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,

   cut_tac, subgoal_tac and thin_tac:

   - Now understand static (Isar) contexts.  As a consequence, users of Isar

     locales are no longer forced to write Isar proof scripts.

     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic

     emulations.

   - INCOMPATIBILITY: names of variables to be instantiated may no

     longer be enclosed in quotes.  Instead, precede variable name with `?'.

     This is consistent with the instantiation attribute "where".

 * Attributes "where" and "of":

   - Now take type variables of instantiated theorem into account when reading

     the instantiation string.  This fixes a bug that caused instantiated

     theorems to have too special types in some circumstances.

   - "where" permits explicit instantiations of type variables.

 * Calculation commands "moreover" and "also" no longer interfere with

   current facts ("this"), admitting arbitrary combinations with "then"

   and derived forms.

 * Locales:

   - Goal statements involving the context element "includes" no longer

     generate theorems with internal delta predicates (those ending on

     "_axioms") in the premise.

     Resolve particular premise with <locale>.intro to obtain old form.

   - Fixed bug in type inference ("unify_frozen") that prevented mix of target

     specification and "includes" elements in goal statement.

   - Rule sets <locale>.intro and <locale>.axioms no longer declared as

     [intro?] and [elim?] (respectively) by default.

   - Experimental command for instantiation of locales in proof contexts:

         instantiate <label>[<attrs>]: <loc>

     Instantiates locale <loc> and adds all its theorems to the current context

     taking into account their attributes.  Label and attrs are optional

     modifiers, like in theorem declarations.  If present, names of

     instantiated theorems are qualified with <label>, and the attributes

     <attrs> are applied after any attributes these theorems might have already.

       If the locale has assumptions, a chained fact of the form

     "<loc> t1 ... tn" is expected from which instantiations of the parameters

     are derived.  The command does not support old-style locales declared

     with "locale (open)".

       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.

 * HOL: Tactic emulation methods induct_tac and case_tac understand static

   (Isar) contexts.

 *** HOL ***

 * Proof import: new image HOL4 contains the imported library from

   the HOL4 system with about 2500 theorems. It is imported by

   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image

   can be used like any other Isabelle image.  See

   HOL/Import/HOL/README for more information.

 * Simplifier:

   - Much improved handling of linear and partial orders.

     Reasoners for linear and partial orders are set up for type classes

     "linorder" and "order" respectively, and are added to the default simpset

     as solvers.  This means that the simplifier can build transitivity chains

     to solve goals from the assumptions.

   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications

     of blast or auto after simplification become unnecessary because the goal

     is solved by simplification already.

 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,

     all proved in axiomatic type classes for semirings, rings and fields.

 * Numerics:

   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are

     now formalized using the Ring_and_Field theory mentioned above.

   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently

     than before, because now they are set up once in a generic manner.

   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.

     Look for the general versions in Ring_and_Field (and Power if they concern

     exponentiation).

 * Type "rat" of the rational numbers is now available in HOL-Complex.

 * Records:

   - Record types are now by default printed with their type abbreviation

     instead of the list of all field types. This can be configured via

     the reference "print_record_type_abbr".

   - Simproc "record_upd_simproc" for simplification of multiple updates added

     (not enabled by default).

   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.

     EX x. x = sel r to True (not enabled by default).

   - Tactic "record_split_simp_tac" to split and simplify records added.

 * 'specification' command added, allowing for definition by

   specification.  There is also an 'ax_specification' command that

   introduces the new constants axiomatically.

 * arith(_tac) is now able to generate counterexamples for reals as well.

 * HOL-Algebra: new locale "ring" for non-commutative rings.

 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function

   definitions, thanks to Sava Krsti\'{c} and John Matthews.

 * HOL-Matrix: a first theory for matrices in HOL with an application of

   matrix theory to linear programming.

 * Unions and Intersections:

   The latex output syntax of UN and INT has been changed

   from "\Union x \in A. B" to "\Union_{x \in A} B"

   i.e. the index formulae has become a subscript.

   Similarly for "\Union x. B", and for \Inter instead of \Union.

 * Unions and Intersections over Intervals:

   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is

   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"

   like in normal math, and corresponding versions for < and for intersection.

 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard

   lexicographic dictonary ordering has been added as "lexord".

 * ML: the legacy theory structures Int and List have been removed. They had

   conflicted with ML Basis Library structures having the same names.

 * 'refute' command added to search for (finite) countermodels.  Only works

   for a fragment of HOL.  The installation of an external SAT solver is

   highly recommended.  See "HOL/Refute.thy" for details.

 * 'quickcheck' command: Allows to find counterexamples by evaluating

   formulae under an assignment of free variables to random values.

   In contrast to 'refute', it can deal with inductive datatypes,

   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"

   for examples.

 *** HOLCF ***

 * Streams now come with concatenation and are part of the HOLCF image

 New in Isabelle2003 (May 2003)

 ------------------------------

 *** General ***

 * Provers/simplifier:

   - Completely reimplemented method simp (ML: Asm_full_simp_tac):

     Assumptions are now subject to complete mutual simplification,

     not just from left to right. The simplifier now preserves

     the order of assumptions.

     Potential INCOMPATIBILITY:

     -- simp sometimes diverges where the old version did

        not, e.g. invoking simp on the goal

         [| P (f x); y = x; f x = f y |] ==> Q

        now gives rise to the infinite reduction sequence

         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...

        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this

        kind of problem.

     -- Tactics combining classical reasoner and simplification (such as auto)

        are also affected by this change, because many of them rely on

        simp. They may sometimes diverge as well or yield a different numbers

        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto

        in case of problems. Sometimes subsequent calls to the classical

        reasoner will fail because a preceeding call to the simplifier too

        eagerly simplified the goal, e.g. deleted redundant premises.

   - The simplifier trace now shows the names of the applied rewrite rules

   - You can limit the number of recursive invocations of the simplifier

     during conditional rewriting (where the simplifie tries to solve the

     conditions before applying the rewrite rule):

     ML "simp_depth_limit := n"

     where n is an integer. Thus you can force termination where previously

     the simplifier would diverge.

   - Accepts free variables as head terms in congruence rules.  Useful in Isar.

   - No longer aborts on failed congruence proof.  Instead, the

     congruence is ignored.

 * Pure: New generic framework for extracting programs from constructive

   proofs. See HOL/Extraction.thy for an example instantiation, as well

   as HOL/Extraction for some case studies.

 * Pure: The main goal of the proof state is no longer shown by default, only

 the subgoals. This behaviour is controlled by a new flag.

    PG menu: Isabelle/Isar -> Settings -> Show Main Goal

 (ML: Proof.show_main_goal).

 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all

 rules whose conclusion matches subgoal 1:

       PG menu: Isabelle/Isar -> Show me -> matching rules

 The rules are ordered by how closely they match the subgoal.

 In particular, rules that solve a subgoal outright are displayed first

 (or rather last, the way they are printed).

 (ML: ProofGeneral.print_intros())

 * Pure: New flag trace_unify_fail causes unification to print

 diagnostic information (PG: in trace buffer) when it fails. This is

 useful for figuring out why single step proofs like rule, erule or

 assumption failed.

 * Pure: Locale specifications now produce predicate definitions

 according to the body of text (covering assumptions modulo local

 definitions); predicate "loc_axioms" covers newly introduced text,

 while "loc" is cumulative wrt. all included locale expressions; the

 latter view is presented only on export into the global theory

 context; potential INCOMPATIBILITY, use "(open)" option to fall back

 on the old view without predicates;

 * Pure: predefined locales "var" and "struct" are useful for sharing

 parameters (as in CASL, for example); just specify something like

 ``var x + var y + struct M'' as import;

 * Pure: improved thms_containing: proper indexing of facts instead of

 raw theorems; check validity of results wrt. current name space;

 include local facts of proof configuration (also covers active

 locales), cover fixed variables in index; may use "_" in term

 specification; an optional limit for the number of printed facts may

 be given (the default is 40);

 * Pure: disallow duplicate fact bindings within new-style theory files

 (batch-mode only);

 * Provers: improved induct method: assumptions introduced by case

 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from

 the goal statement); "foo" still refers to all facts collectively;

 * Provers: the function blast.overloaded has been removed: all constants

 are regarded as potentially overloaded, which improves robustness in exchange

 for slight decrease in efficiency;

 * Provers/linorder: New generic prover for transitivity reasoning over

 linear orders.  Note: this prover is not efficient!

 * Isar: preview of problems to finish 'show' now produce an error

 rather than just a warning (in interactive mode);

 *** HOL ***

 * arith(_tac)

  - Produces a counter example if it cannot prove a goal.

    Note that the counter example may be spurious if the goal is not a formula

    of quantifier-free linear arithmetic.

    In ProofGeneral the counter example appears in the trace buffer.

  - Knows about div k and mod k where k is a numeral of type nat or int.

  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free

    linear arithmetic fails. This takes account of quantifiers and divisibility.

    Presburger arithmetic can also be called explicitly via presburger(_tac).

 * simp's arithmetic capabilities have been enhanced a bit: it now

 takes ~= in premises into account (by performing a case split);

 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands

 are distributed over a sum of terms;

 * New tactic "trans_tac" and method "trans" instantiate

 Provers/linorder.ML for axclasses "order" and "linorder" (predicates

 "<=", "<" and "=").

 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main

 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";

 * 'typedef' command has new option "open" to suppress the set

 definition;

 * functions Min and Max on finite sets have been introduced (theory

 Finite_Set);

 * attribute [symmetric] now works for relations as well; it turns

 (x,y) : R^-1 into (y,x) : R, and vice versa;

 * induct over a !!-quantified statement (say !!x1..xn):

   each "case" automatically performs "fix x1 .. xn" with exactly those names.

 * Map: `empty' is no longer a constant but a syntactic abbreviation for

 %x. None. Warning: empty_def now refers to the previously hidden definition

 of the empty set.

 * Algebra: formalization of classical algebra.  Intended as base for

 any algebraic development in Isabelle.  Currently covers group theory

 (up to Sylow's theorem) and ring theory (Universal Property of

 Univariate Polynomials).  Contributions welcome;

 * GroupTheory: deleted, since its material has been moved to Algebra;

 * Complex: new directory of the complex numbers with numeric constants,

 nonstandard complex numbers, and some complex analysis, standard and

 nonstandard (Jacques Fleuriot);

 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;

 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques

 Fleuriot);

 * Real/HahnBanach: updated and adapted to locales;

 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,

 Gray and Kramer);

 * UNITY: added the Meier-Sanders theory of progress sets;

 * MicroJava: bytecode verifier and lightweight bytecode verifier

 as abstract algorithms, instantiated to the JVM;

 * Bali: Java source language formalization. Type system, operational

 semantics, axiomatic semantics. Supported language features:

 classes, interfaces, objects,virtual methods, static methods,

 static/instance fields, arrays, access modifiers, definite

 assignment, exceptions.

 *** ZF ***

 * ZF/Constructible: consistency proof for AC (Gdel's constructible

 universe, etc.);

 * Main ZF: virtually all theories converted to new-style format;

 *** ML ***

 * Pure: Tactic.prove provides sane interface for internal proofs;

 omits the infamous "standard" operation, so this is more appropriate

 than prove_goalw_cterm in many situations (e.g. in simprocs);

 * Pure: improved error reporting of simprocs;

 * Provers: Simplifier.simproc(_i) provides sane interface for setting

 up simprocs;

 *** Document preparation ***

 * uses \par instead of \\ for line breaks in theory text. This may

 shift some page breaks in large documents. To get the old behaviour

 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.

 * minimized dependencies of isabelle.sty and isabellesym.sty on

 other packages

 * \<euro> now needs package babel/greek instead of marvosym (which

 broke \Rightarrow)

 * normal size for \<zero>...\<nine> (uses \mathbf instead of

 textcomp package)

 New in Isabelle2002 (March 2002)

 --------------------------------

 *** Document preparation ***

 * greatly simplified document preparation setup, including more

 graceful interpretation of isatool usedir -i/-d/-D options, and more

 instructive isatool mkdir; users should basically be able to get

 started with "isatool mkdir HOL Test && isatool make"; alternatively,

 users may run a separate document processing stage manually like this:

 "isatool usedir -D output HOL Test && isatool document Test/output";

 * theory dependency graph may now be incorporated into documents;

 isatool usedir -g true will produce session_graph.eps/.pdf for use

 with \includegraphics of LaTeX;

 * proper spacing of consecutive markup elements, especially text

 blocks after section headings;

 * support bold style (for single symbols only), input syntax is like

 this: "\<^bold>\<alpha>" or "\<^bold>A";

 * \<bullet> is now output as bold \cdot by default, which looks much

 better in printed text;

 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;

 note that these symbols are currently unavailable in Proof General /

 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;

 * isatool latex no longer depends on changed TEXINPUTS, instead

 isatool document copies the Isabelle style files to the target

 location;

 *** Isar ***

 * Pure/Provers: improved proof by cases and induction;

   - 'case' command admits impromptu naming of parameters (such as

     "case (Suc n)");

   - 'induct' method divinates rule instantiation from the inductive

     claim; no longer requires excessive ?P bindings for proper

     instantiation of cases;

   - 'induct' method properly enumerates all possibilities of set/type

     rules; as a consequence facts may be also passed through *type*

     rules without further ado;

   - 'induct' method now derives symbolic cases from the *rulified*

     rule (before it used to rulify cases stemming from the internal

     atomized version); this means that the context of a non-atomic

     statement becomes is included in the hypothesis, avoiding the

     slightly cumbersome show "PROP ?case" form;

   - 'induct' may now use elim-style induction rules without chaining

     facts, using ``missing'' premises from the goal state; this allows

     rules stemming from inductive sets to be applied in unstructured

     scripts, while still benefitting from proper handling of non-atomic

     statements; NB: major inductive premises need to be put first, all

     the rest of the goal is passed through the induction;

   - 'induct' proper support for mutual induction involving non-atomic

     rule statements (uses the new concept of simultaneous goals, see

     below);

   - append all possible rule selections, but only use the first

     success (no backtracking);

   - removed obsolete "(simplified)" and "(stripped)" options of methods;

   - undeclared rule case names default to numbers 1, 2, 3, ...;

   - added 'print_induct_rules' (covered by help item in recent Proof

     General versions);

   - moved induct/cases attributes to Pure, methods to Provers;

   - generic method setup instantiated for FOL and HOL;

 * Pure: support multiple simultaneous goal statements, for example

 "have a: A and b: B" (same for 'theorem' etc.); being a pure

 meta-level mechanism, this acts as if several individual goals had

 been stated separately; in particular common proof methods need to be

 repeated in order to cover all claims; note that a single elimination

 step is *not* sufficient to establish the two conjunctions, so this

 fails:

   assume "A & B" then have A and B ..   (*".." fails*)

 better use "obtain" in situations as above; alternative refer to

 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;

 * Pure: proper integration with ``locales''; unlike the original

 version by Florian Kammller, Isar locales package high-level proof

 contexts rather than raw logical ones (e.g. we admit to include

 attributes everywhere); operations on locales include merge and

 rename; support for implicit arguments (``structures''); simultaneous

 type-inference over imports and text; see also HOL/ex/Locales.thy for

 some examples;

 * Pure: the following commands have been ``localized'', supporting a

 target locale specification "(in name)": 'lemma', 'theorem',

 'corollary', 'lemmas', 'theorems', 'declare'; the results will be

 stored both within the locale and at the theory level (exported and

 qualified by the locale name);

 * Pure: theory goals may now be specified in ``long'' form, with

 ad-hoc contexts consisting of arbitrary locale elements. for example

 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and

 definitions may be given, too); the result is a meta-level rule with

 the context elements being discharged in the obvious way;

 * Pure: new proof command 'using' allows to augment currently used

 facts after a goal statement ('using' is syntactically analogous to

 'apply', but acts on the goal's facts only); this allows chained facts

 to be separated into parts given before and after a claim, as in

 ``from a and b have C using d and e <proof>'';

 * Pure: renamed "antecedent" case to "rule_context";

 * Pure: new 'judgment' command records explicit information about the

 object-logic embedding (used by several tools internally); no longer

 use hard-wired "Trueprop";

 * Pure: added 'corollary' command;

 * Pure: fixed 'token_translation' command;

 * Pure: removed obsolete 'exported' attribute;

 * Pure: dummy pattern "_" in is/let is now automatically lifted over

 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")

 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");

 * Pure: method 'atomize' presents local goal premises as object-level

 statements (atomic meta-level propositions); setup controlled via

 rewrite rules declarations of 'atomize' attribute; example

 application: 'induct' method with proper rule statements in improper

 proof *scripts*;

 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)

 now consider the syntactic context of assumptions, giving a better

 chance to get type-inference of the arguments right (this is

 especially important for locales);

 * Pure: "sorry" no longer requires quick_and_dirty in interactive

 mode;

 * Pure/obtain: the formal conclusion "thesis", being marked as

 ``internal'', may no longer be reference directly in the text;

 potential INCOMPATIBILITY, may need to use "?thesis" in rare

 situations;

 * Pure: generic 'sym' attribute which declares a rule both as pure

 'elim?' and for the 'symmetric' operation;

 * Pure: marginal comments ``--'' may now occur just anywhere in the

 text; the fixed correlation with particular command syntax has been

 discontinued;

 * Pure: new method 'rules' is particularly well-suited for proof

 search in intuitionistic logic; a bit slower than 'blast' or 'fast',

 but often produces more compact proof terms with less detours;

 * Pure/Provers/classical: simplified integration with pure rule

 attributes and methods; the classical "intro?/elim?/dest?"

 declarations coincide with the pure ones; the "rule" method no longer

 includes classically swapped intros; "intro" and "elim" methods no

 longer pick rules from the context; also got rid of ML declarations

 AddXIs/AddXEs/AddXDs; all of this has some potential for

 INCOMPATIBILITY;

 * Provers/classical: attribute 'swapped' produces classical inversions

 of introduction rules;

 * Provers/simplifier: 'simplified' attribute may refer to explicit

 rules instead of full simplifier context; 'iff' attribute handles

 conditional rules;

 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;

 * HOL: 'recdef' now fails on unfinished automated proofs, use

 "(permissive)" option to recover old behavior;

 * HOL: 'inductive' no longer features separate (collective) attributes

 for 'intros' (was found too confusing);

 * HOL: properly declared induction rules less_induct and

 wf_induct_rule;

 *** HOL ***

 * HOL: moved over to sane numeral syntax; the new policy is as

 follows:

   - 0 and 1 are polymorphic constants, which are defined on any

   numeric type (nat, int, real etc.);

   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based

   binary representation internally;

   - type nat has special constructor Suc, and generally prefers Suc 0

   over 1::nat and Suc (Suc 0) over 2::nat;

 This change may cause significant problems of INCOMPATIBILITY; here

 are some hints on converting existing sources:

   - due to the new "num" token, "-0" and "-1" etc. are now atomic

   entities, so expressions involving "-" (unary or binary minus) need

   to be spaced properly;

   - existing occurrences of "1" may need to be constraint "1::nat" or

   even replaced by Suc 0; similar for old "2";

   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";

   - remove all special provisions on numerals in proofs;

 * HOL: simp rules nat_number expand numerals on nat to Suc/0

 representation (depends on bin_arith_simps in the default context);

 * HOL: symbolic syntax for x^2 (numeral 2);

 * HOL: the class of all HOL types is now called "type" rather than

 "term"; INCOMPATIBILITY, need to adapt references to this type class

 in axclass/classes, instance/arities, and (usually rare) occurrences

 in typings (of consts etc.); internally the class is called

 "HOL.type", ML programs should refer to HOLogic.typeS;

 * HOL/record package improvements:

   - new derived operations "fields" to build a partial record section,

     "extend" to promote a fixed record to a record scheme, and

     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*

     declared as simp by default;

   - shared operations ("more", "fields", etc.) now need to be always

     qualified) --- potential INCOMPATIBILITY;

   - removed "make_scheme" operations (use "make" with "extend") --

     INCOMPATIBILITY;

   - removed "more" class (simply use "term") -- INCOMPATIBILITY;

   - provides cases/induct rules for use with corresponding Isar

     methods (for concrete records, record schemes, concrete more

     parts, and schematic more parts -- in that order);

   - internal definitions directly based on a light-weight abstract

     theory of product types over typedef rather than datatype;

 * HOL: generic code generator for generating executable ML code from

 specifications; specific support for HOL constructs such as inductive

 datatypes and sets, as well as recursive functions; can be invoked

 via 'generate_code' theory section;

 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);

 * HOL: consolidated and renamed several theories.  In particular:

         Ord.thy has been absorbed into HOL.thy

         String.thy has been absorbed into List.thy

 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"

 (beware of argument permutation!);

 * HOL: linorder_less_split superseded by linorder_cases;

 * HOL/List: "nodups" renamed to "distinct";

 * HOL: added "The" definite description operator; move Hilbert's "Eps"

 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:

   - Ex_def has changed, now need to use some_eq_ex

 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so

 in this (rare) case use:

   delSWrapper "split_all_tac"

   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)

 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS

 MAY FAIL;

 * HOL: introduced f^n = f o ... o f; warning: due to the limits of

 Isabelle's type classes, ^ on functions and relations has too general

 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be

 necessary to attach explicit type constraints;

 * HOL/Relation: the prefix name of the infix "O" has been changed from

 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been

 renamed accordingly (eg "compI" -> "rel_compI").

 * HOL: syntax translations now work properly with numerals and records

 expressions;

 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead

 of "lam" -- INCOMPATIBILITY;

 * HOL: got rid of some global declarations (potential INCOMPATIBILITY

 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"

 renamed "Product_Type.unit";

 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl

 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or

 the "cases" method);

 * HOL/GroupTheory: group theory examples including Sylow's theorem (by

 Florian Kammller);

 * HOL/IMP: updated and converted to new-style theory format; several

 parts turned into readable document, with proper Isar proof texts and

 some explanations (by Gerwin Klein);

 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);

 * HOL-Hyperreal is now a logic image;

 *** HOLCF ***

 * Isar: consts/constdefs supports mixfix syntax for continuous

 operations;

 * Isar: domain package adapted to new-style theory format, e.g. see

 HOLCF/ex/Dnat.thy;

 * theory Lift: proper use of rep_datatype lift instead of ML hacks --

 potential INCOMPATIBILITY; now use plain induct_tac instead of former

 lift.induct_tac, always use UU instead of Undef;

 * HOLCF/IMP: updated and converted to new-style theory;

 *** ZF ***

 * Isar: proper integration of logic-specific tools and packages,

 including theory commands '(co)inductive', '(co)datatype',

 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',

 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');

 * theory Main no longer includes AC; for the Axiom of Choice, base

 your theory on Main_ZFC;

 * the integer library now covers quotients and remainders, with many

 laws relating division to addition, multiplication, etc.;

 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a

 typeless version of the formalism;

 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory

 format;

 * ZF/Induct: new directory for examples of inductive definitions,

 including theory Multiset for multiset orderings; converted to

 new-style theory format;

 * ZF: many new theorems about lists, ordinals, etc.;

 *** General ***

 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference

 variable proof controls level of detail: 0 = no proofs (only oracle

 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see

 also ref manual for further ML interfaces;

 * Pure/axclass: removed obsolete ML interface

 goal_subclass/goal_arity;

 * Pure/syntax: new token syntax "num" for plain numerals (without "#"

 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now

 separate tokens, so expressions involving minus need to be spaced

 properly;

 * Pure/syntax: support non-oriented infixes, using keyword "infix"

 rather than "infixl" or "infixr";

 * Pure/syntax: concrete syntax for dummy type variables admits genuine

 sort constraint specifications in type inference; e.g. "x::_::foo"

 ensures that the type of "x" is of sort "foo" (but not necessarily a

 type variable);

 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"

 control output of nested => (types); the default behavior is

 "type_brackets";

 * Pure/syntax: builtin parse translation for "_constify" turns valued

 tokens into AST constants;

 * Pure/syntax: prefer later declarations of translations and print

 translation functions; potential INCOMPATIBILITY: need to reverse

 multiple declarations for same syntax element constant;

 * Pure/show_hyps reset by default (in accordance to existing Isar

 practice);

 * Provers/classical: renamed addaltern to addafter, addSaltern to

 addSafter;

 * Provers/clasimp: ``iff'' declarations now handle conditional rules

 as well;

 * system: tested support for MacOS X; should be able to get Isabelle +

 Proof General to work in a plain Terminal after installing Poly/ML

 (e.g. from the Isabelle distribution area) and GNU bash alone

 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol

 support requires further installations, e.g. from

 http://fink.sourceforge.net/);

 * system: support Poly/ML 4.1.1 (able to manage larger heaps);

 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead

 of 40 MB), cf. ML_OPTIONS;

 * system: Proof General keywords specification is now part of the

 Isabelle distribution (see etc/isar-keywords.el);

 * system: support for persistent Proof General sessions (refrain from

 outdating all loaded theories on startup); user may create writable

 logic images like this: ``isabelle -q HOL Test'';

 * system: smart selection of Isabelle process versus Isabelle

 interface, accommodates case-insensitive file systems (e.g. HFS+); may

 run both "isabelle" and "Isabelle" even if file names are badly

 damaged (executable inspects the case of the first letter of its own

 name); added separate "isabelle-process" and "isabelle-interface";

 * system: refrain from any attempt at filtering input streams; no

 longer support ``8bit'' encoding of old isabelle font, instead proper

 iso-latin characters may now be used; the related isatools

 "symbolinput" and "nonascii" have disappeared as well;

 * system: removed old "xterm" interface (the print modes "xterm" and

 "xterm_color" are still available for direct use in a suitable

 terminal);

 New in Isabelle99-2 (February 2001)

 -----------------------------------

 *** Overview of INCOMPATIBILITIES ***

 * HOL: please note that theories in the Library and elsewhere often use the

 new-style (Isar) format; to refer to their theorems in an ML script you must

 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";

 * HOL: inductive package no longer splits induction rule aggressively,

 but only as far as specified by the introductions given; the old

 format may be recovered via ML function complete_split_rule or attribute

 'split_rule (complete)';

 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,

 gfp_Tarski to gfp_unfold;