Isabelle NEWS -- history user-relevant changes

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

New in this Isabelle version

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

*** General ***

* More uniform information about legacy features, notably a

warning/error of "Legacy feature: ...", depending on the state of the

tolerate_legacy_features flag (default true).

* Theory syntax: the header format ``theory A = B + C:'' has been

discontinued in favour of ``theory A imports B C begin''.  Use isatool

fixheaders to convert existing theory files.  INCOMPATIBILITY.

* Theory syntax: the old non-Isar theory file format has been

discontinued altogether.  Note that ML proof scripts may still be used

with Isar theories; migration is usually quite simple with the ML

function use_legacy_bindings.  INCOMPATIBILITY.

* Theory syntax: some popular names (e.g. 'class', 'declaration',

'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double

quotes.

* 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.

* Local theory targets may be specified by non-nested blocks of

``context/locale/class ... begin'' followed by ``end''.  The body may

contain definitions, theorems etc., including any derived mechanism

that has been implemented on top of these primitives.  This concept

generalizes the existing ``theorem (in ...)'' towards more versatility

and scalability.

* Proof General interface: proper undo of final 'end' command;

discontinued Isabelle/classic mode (ML proof scripts).

*** Document preparation ***

* Added antiquotation @{theory name} which prints the given name,

after checking that it refers to a valid ancestor theory in the

current context.

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

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

* Added antiquotation @{abbrev "c args"} which prints the abbreviation

"c args == rhs" given in the current context.  (Any number of

arguments may be given on the LHS.)

*** Pure ***

* code generator: 

  - Isar "definition"s and primitive instance definitions are added explicitly

    to the table of defining equations

  - primitive definitions are not used as defining equations by default any longer

  - defining equations are now definitly restricted to meta "==" and object

        equality "="

  - HOL theories have been adopted accordingly

* 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 OCaml code to a file:

        code_gen <list of constants (term syntax)> (OCaml <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.

Theorem attributs for selecting and transforming function equations theorems:

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

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

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

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

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

    code_const <and-list of constants (term syntax)>

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

    code_type <and-list of type constructors>

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

    code_instance <and-list of instances>

      {(target)}+

        where instance ::= <type constructor> :: <class>

    code_class <and_list of classes>

      {(target) <and-list of class target syntax>}+

        where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?

code_instance and code_class only apply to target Haskell.

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

Doc/Isar/Advanced/Codegen/ provides a tutorial.

* 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: the assumptions of a long theorem statement are available as

"assms" fact in the proof context.  This is more appropriate than the

(historical) "prems", which refers to all assumptions of the current

context, including those from the target locale, proof body etc.

* Isar: 'print_statement' prints theorems from the current theory or

proof context in long statement form, according to the syntax of a

top-level lemma.

* Isar: 'obtain' takes an optional case name for the local context

introduction rule (default "that").

* Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use

explicit (is "_ ==> ?foo") in the rare cases where this still happens

to occur.

* Pure: syntax "CONST name" produces a fully internalized constant

according to the current context.  This is particularly useful for

syntax translations that should refer to internal constant

representations independently of name spaces.

* Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"

instead of "FOO ". This allows multiple binder declarations to coexist

in the same context.  INCOMPATIBILITY.

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

primitive that also works in a locale context (both for constants and

fixed variables).  Type declaration and internal syntactic

representation of given constants retrieved from the context.

* Isar/locales: new derived specification elements 'axiomatization',

'definition', 'abbreviation', which support type-inference, admit

object-level specifications (equality, equivalence).  See also the

isar-ref manual.  Examples:

  axiomatization

    eq  (infix "===" 50) where

    eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"

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

  definition g where "g x = f x x"

  abbreviation

    neq  (infix "=!=" 50) where

    "x =!= y == ~ (x === y)"

These specifications may be also used in a locale context.  Then the

constants being introduced depend on certain fixed parameters, and the

constant name is qualified by the locale base name.  An internal

abbreviation takes care for convenient input and output, making the

parameters implicit and using the original short name.  See also

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 'notation' instead of raw 'syntax', and

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

* Pure: command 'print_abbrevs' prints all constant abbreviations of

the current context.  Print mode "no_abbrevs" prevents inversion of

abbreviations on output.

* Isar/locales: improved parameter handling:

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

- parameter renamings are no longer required to be injective.

  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 ***

* case expressions and primrec: missing cases now mapped to "undefined"

instead of "arbitrary"

* new constant "undefined" with axiom "undefined x = undefined"

* new class "default" with associated constant "default"

* Library/Pretty_Int.thy: maps HOL numerals on target language integer literals

    when generating code.

* Library/Pretty_Char.thy: maps HOL characters on target language character literals

    when generating code.

* Library/Commutative_Ring.thy: switched from recdef to function package;

    constants add, mul, pow now curried.  Infix syntax for algebraic operations.

* Some steps towards more uniform lattice theory development in HOL.

    constants "meet" and "join" now named "inf" and "sup"

    constant "Meet" now named "Inf"

    classes "meet_semilorder" and "join_semilorder" now named

      "lower_semilattice" and "upper_semilattice"

    class "lorder" now named "lattice"

    class "comp_lat" now named "complete_lattice"

    Instantiation of lattice classes allows explicit definitions

    for "inf" and "sup" operations.

  INCOMPATIBILITY. Theorem renames:

    meet_left_le            ~> inf_le1

    meet_right_le           ~> inf_le2

    join_left_le            ~> sup_ge1

    join_right_le           ~> sup_ge2

    meet_join_le            ~> inf_sup_ord

    le_meetI                ~> le_infI

    join_leI                ~> le_supI

    le_meet                 ~> le_inf_iff

    le_join                 ~> ge_sup_conv

    meet_idempotent         ~> inf_idem

    join_idempotent         ~> sup_idem

    meet_comm               ~> inf_commute

    join_comm               ~> sup_commute

    meet_leI1               ~> le_infI1

    meet_leI2               ~> le_infI2

    le_joinI1               ~> le_supI1

    le_joinI2               ~> le_supI2

    meet_assoc              ~> inf_assoc

    join_assoc              ~> sup_assoc

    meet_left_comm          ~> inf_left_commute

    meet_left_idempotent    ~> inf_left_idem

    join_left_comm          ~> sup_left_commute

    join_left_idempotent    ~> sup_left_idem

    meet_aci                ~> inf_aci

    join_aci                ~> sup_aci

    le_def_meet             ~> le_iff_inf

    le_def_join             ~> le_iff_sup

    join_absorp2            ~> sup_absorb2

    join_absorp1            ~> sup_absorb1

    meet_absorp1            ~> inf_absorb1

    meet_absorp2            ~> inf_absorb2

    meet_join_absorp        ~> inf_sup_absorb

    join_meet_absorp        ~> sup_inf_absorb

    distrib_join_le         ~> distrib_sup_le

    distrib_meet_le         ~> distrib_inf_le

    add_meet_distrib_left   ~> add_inf_distrib_left

    add_join_distrib_left   ~> add_sup_distrib_left

    is_join_neg_meet        ~> is_join_neg_inf

    is_meet_neg_join        ~> is_meet_neg_sup

    add_meet_distrib_right  ~> add_inf_distrib_right

    add_join_distrib_right  ~> add_sup_distrib_right

    add_meet_join_distribs  ~> add_sup_inf_distribs

    join_eq_neg_meet        ~> sup_eq_neg_inf

    meet_eq_neg_join        ~> inf_eq_neg_sup

    add_eq_meet_join        ~> add_eq_inf_sup

    meet_0_imp_0            ~> inf_0_imp_0

    join_0_imp_0            ~> sup_0_imp_0

    meet_0_eq_0             ~> inf_0_eq_0

    join_0_eq_0             ~> sup_0_eq_0

    neg_meet_eq_join        ~> neg_inf_eq_sup

    neg_join_eq_meet        ~> neg_sup_eq_inf

    join_eq_if              ~> sup_eq_if

    mono_meet               ~> mono_inf

    mono_join               ~> mono_sup

    meet_bool_eq            ~> inf_bool_eq

    join_bool_eq            ~> sup_bool_eq

    meet_fun_eq             ~> inf_fun_eq

    join_fun_eq             ~> sup_fun_eq

    meet_set_eq             ~> inf_set_eq

    join_set_eq             ~> sup_set_eq

    meet1_iff               ~> inf1_iff

    meet2_iff               ~> inf2_iff

    meet1I                  ~> inf1I

    meet2I                  ~> inf2I

    meet1D1                 ~> inf1D1

    meet2D1                 ~> inf2D1

    meet1D2                 ~> inf1D2

    meet2D2                 ~> inf2D2

    meet1E                  ~> inf1E

    meet2E                  ~> inf2E

    join1_iff               ~> sup1_iff

    join2_iff               ~> sup2_iff

    join1I1                 ~> sup1I1

    join2I1                 ~> sup2I1

    join1I1                 ~> sup1I1

    join2I2                 ~> sup1I2

    join1CI                 ~> sup1CI

    join2CI                 ~> sup2CI

    join1E                  ~> sup1E

    join2E                  ~> sup2E

    is_meet_Meet            ~> is_meet_Inf

    Meet_bool_def           ~> Inf_bool_def

    Meet_fun_def            ~> Inf_fun_def

    Meet_greatest           ~> Inf_greatest

    Meet_lower              ~> Inf_lower

    Meet_set_def            ~> Inf_set_def

    listsp_meetI            ~> listsp_infI

    listsp_meet_eq          ~> listsp_inf_eq

    meet_min                ~> inf_min

    join_max                ~> sup_max

* Classes "order" and "linorder": facts "refl", "trans" and

"cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to

avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.

* Classes "order" and "linorder": 

potential INCOMPATIBILITY: order of proof goals in order/linorder instance

proofs changed.

* Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.

INCOMPATIBILITY.

* Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.

INCOMPATIBILITY.

* Added syntactic class "size"; overloaded constant "size" now has

type "'a::size ==> bool"

* Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op

dvd" to "Divides.div", "Divides.mod" and "Divides.dvd". INCOMPATIBILITY.

* Added method "lexicographic_order" automatically synthesizes

termination relations as lexicographic combinations of size measures

-- 'function' package.

* HOL/records: generalised field-update to take a function on the

field rather than the new value: r(|A := x|) is translated to A_update

(K x) r The K-combinator that is internally used is called K_record.

INCOMPATIBILITY: Usage of the plain update functions has to be

adapted.

* axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and

0 * x = 0, which are required for a semiring.  Richer structures do

not inherit from semiring_0 anymore, because this property is a

theorem there, not an axiom.  INCOMPATIBILITY: In instances of

semiring_0, there is more to prove, but this is mostly trivial.

* axclass "recpower" was generalized to arbitrary monoids, not just

commutative semirings.  INCOMPATIBILITY: If you use recpower and need

commutativity or a semiring property, add the corresponding classes.

* Unified locale partial_order with class definition (cf. theory

Orderings), added parameter ``less''.  INCOMPATIBILITY.

* Constant "List.list_all2" in List.thy now uses authentic syntax.

INCOMPATIBILITY: translations containing list_all2 may go wrong.  On

Isar level, use abbreviations instead.

* Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:

rarely occuring name references (e.g. ``List.op mem.simps'') require

renaming (e.g. ``List.memberl.simps'').

* Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".

INCOMPATIBILITY.

* Added theory Code_Generator providing class '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]"'' produces ``[b,c,a]'' (without proof).  This command is

suitable for heavy-duty computations because the functions are

compiled to ML first.

* 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.

* Relations less (<) and less_eq (<=) are also available on type bool.

Modified syntax to disallow nesting without explicit parentheses,

e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".

* "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 declared as ``simp''.

* Theorem setsum_mult renamed to setsum_right_distrib.

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

``rule'' method.

* Reimplemented methods ``sat'' and ``satx'', with several

improvements: goals no longer need to be stated as "<prems> ==>

False", equivalences (i.e. "=" on type bool) are handled, variable

names of the form "lit_<n>" are no longer reserved, significant

speedup.

* Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.

zChaff is still supported as well.

* 'inductive' and 'datatype': provide projections of mutual rules,

bundled as foo_bar.inducts;

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

Library.

* Library: moved theory Accessible_Part to main HOL.

* Library: added theory Coinductive_List of potentially infinite lists

as greatest fixed-point.

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

association lists.

* Added proof method ``evaluation'' for efficiently solving a goal

(i.e. a boolean expression) by compiling it to ML. The goal is

"proved" (via an oracle) if it evaluates to True.

* Linear arithmetic now splits certain operators (e.g. min, max, abs)

also when invoked by the simplifier.  This results in the simplifier

being more powerful on arithmetic goals.  INCOMPATIBILITY.  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 ***

* Formalisation of ideals and the quotient construction over rings.

* Order and lattice theory no longer based on records.

INCOMPATIBILITY.

* Renamed lemmas least_carrier -> least_closed and greatest_carrier ->

greatest_closed.  INCOMPATIBILITY.

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

Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations

of algebraic structures.

* Renamed theory CRing to Ring.

*** HOL-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.

* Real: New axiomatic classes formalize real normed vector spaces and

algebras, using new overloaded constants scaleR :: real => 'a => 'a

and norm :: 'a => real.

* Real: New constant of_real :: real => 'a::real_algebra_1 injects

from reals into other types. The overloaded constant Reals :: 'a set

is now defined as range of_real; potential INCOMPATIBILITY.

* Hyperreal: Several constants that previously worked only for the

reals have been generalized, so they now work over arbitrary vector

spaces. Type annotations may need to be added in some cases; potential

INCOMPATIBILITY.

  Infinitesimal  :: ('a::real_normed_vector) star set"

  HFinite        :: ('a::real_normed_vector) star set"

  HInfinite      :: ('a::real_normed_vector) star set"

  approx         :: ('a::real_normed_vector) star => 'a star => bool

  monad          :: ('a::real_normed_vector) star => 'a star set

  galaxy         :: ('a::real_normed_vector) star => 'a star set

  (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool

  (NS)convergent :: (nat => 'a::real_normed_vector) => bool

  (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool

  (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool

  (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool

  is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool

  deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool

* Complex: Some complex-specific constants are now abbreviations for

overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =

hnorm.  Other constants have been entirely removed in favor of the

polymorphic versions (INCOMPATIBILITY):

  approx        <-- capprox

  HFinite       <-- CFinite

  HInfinite     <-- CInfinite

  Infinitesimal <-- CInfinitesimal

  monad         <-- cmonad

  galaxy        <-- cgalaxy

  (NS)LIM       <-- (NS)CLIM, (NS)CRLIM

  is(NS)Cont    <-- is(NS)Contc, is(NS)contCR

  (ns)deriv     <-- (ns)cderiv

*** ML ***

* Context data interfaces (Theory/Proof/GenericDataFun): removed

name/print, uninitialized data defaults to ad-hoc copy of empty value,

init only required for impure data.  INCOMPATIBILITY: empty really

need to be empty (no dependencies on theory content!)

* ML within Isar: antiquotations allow to embed statically-checked

formal entities in the source, referring to the context available at

compile-time.  For example:

ML {* @{typ "'a => 'b"} *}

ML {* @{term "%x. x"} *}

ML {* @{prop "x == y"} *}

ML {* @{ctyp "'a => 'b"} *}

ML {* @{cterm "%x. x"} *}

ML {* @{cprop "x == y"} *}

ML {* @{thm asm_rl} *}

ML {* @{thms asm_rl} *}

ML {* @{const_name c} *}

ML {* @{const_syntax c} *}

ML {* @{context} *}

ML {* @{theory} *}

ML {* @{theory Pure} *}

ML {* @{simpset} *}

ML {* @{claset} *}

ML {* @{clasimpset} *}

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

* ML in Isar: improved error reporting; extra verbosity with

Toplevel.debug enabled.

* 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". Compare this with "map" which

would *not* apply its argument function simulatanously but in

sequence; "fold_burrow" has an additional context.

* 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_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: added general ``divide_and_conquer'' combinator on

lists.

* 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,

potential INCOMPATIBILITY.