Isabelle NEWS -- history of user-visible changes

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New in Isabelle???? (DATE ????)

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*** General Changes ***

* hierachically structured name spaces (for consts, types, axms, thms

etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of

old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:

isatool fixdots ensures space after dots (e.g. "%x. x"); set

long_names for fully qualified output names; NOTE: ML programs

(special tactics, packages etc.) referring to internal names may have

to be adapted to cope with fully qualified names; in case of severe

backward campatibility problems try setting 'global_names' at compile

time to have enrything declared within a flat name space; one may also

fine tune name declarations in theories via the 'global' and 'local'

section;

* reimplemented the implicit simpset and claset using the new anytype

data filed in signatures; references simpset:simpset ref etc. are

replaced by functions simpset:unit->simpset and

simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp

to patch your ML files accordingly;

* HTML output now includes theory graph data for display with Java

applet or isatool browser; data generated automatically via isatool

usedir (see -i option, ISABELLE_USEDIR_OPTIONS);

* defs may now be conditional; improved rewrite_goals_tac to handle

conditional equations;

* defs now admits additional type arguments, using TYPE('a) syntax;

* theory aliases via merge (e.g. M=A+B+C) no longer supported, always

creates a new theory node; implicit merge of thms' signatures is

restricted to 'trivial' ones; COMPATIBILITY: one may have to use

transfer:theory->thm->thm in (rare) cases;

* improved handling of draft signatures / theories; draft thms (and

ctyps, cterms) are automatically promoted to real ones;

* slightly changed interfaces for oracles: admit many per theory, named

(e.g. oracle foo = mlfun), additional name argument for invoke_oracle;

* print_goals: optional output of const types (set show_consts and

show_types);

* improved output of warnings (###) / errors (***);

* subgoal_tac displays a warning if the new subgoal has type variables;

* removed old README and Makefiles;

* replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;

* removed obsolete init_pps and init_database;

* deleted the obsolete tactical STATE, which was declared by

    fun STATE tacfun st = tacfun st st;

* cd, use, use etc. now support path variables, e.g. ~ (which

abbreviates $HOME), or $ISABELLE_HOME;

* changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:

use isatool fixseq to adapt your ML programs (this works for fully

qualified references to the Sequence structure only!);

*** Classical Reasoner ***

* Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new

tactics that use classical reasoning to simplify a subgoal without

splitting it into several subgoals;

* Safe_tac: like safe_tac but uses the default claset;

*** Simplifier ***

* added simplification meta rules:

    (asm_)(full_)simplify: simpset -> thm -> thm;

* simplifier.ML no longer part of Pure -- has to be loaded by object

logics (again);

* added prems argument to simplification procedures;

* HOL, FOL, ZF: added infix function `addsplits':

  instead of `<simpset> setloop (split_tac <thms>)'

  you can simply write `<simpset> addsplits <thms>'

*** Syntax ***

* TYPE('a) syntax for type reflection terms;

* no longer handles consts with name "" -- declare as 'syntax' instead;

* pretty printer: changed order of mixfix annotation preference (again!);

* Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;

*** HOL ***

* HOL: there is a new splitter `split_asm_tac' that can be used e.g. 

  with `addloop' of the simplifier to faciliate case splitting in premises.

* HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;

* HOL/Auth: new protocol proofs including some for the Internet

  protocol TLS;

* HOL/Map: new theory of `maps' a la VDM;

* HOL/simplifier: simplification procedures nat_cancel_sums for

cancelling out common nat summands from =, <, <= (in)equalities, or

differences; simplification procedures nat_cancel_factor for

cancelling common factor from =, <, <= (in)equalities over natural

sums;  nat_cancel contains both kinds of procedures;

* HOL/simplifier: terms of the form

  `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)

  are rewritten to

  `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',

  and those of the form

  `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)

  are rewritten to

  `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',

* HOL/datatype

  Each datatype `t' now comes with a theorem `split_t_case' of the form

  P(t_case f1 ... fn x) =

     ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &

        ...

       (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))

     )

  which can be added to a simpset via `addsplits'. The existing theorems

  expand_list_case and expand_option_case have been renamed to

  split_list_case and split_option_case.

  Additionally, there is a theorem `split_t_case_asm' of the form

  P(t_case f1 ... fn x) =

    ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |

        ...

       (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))

     )

  it be used with the new `split_asm_tac'.

* HOL/Arithmetic:

  - `pred n' is automatically converted to `n-1'.

    Users are strongly encouraged not to use `pred' any longer,

    because it will disappear altogether at some point.

  - Users are strongly encouraged to write "0 < n" rather than

    "n ~= 0". Theorems and proof tools have been modified towards this

    `standard'.

* HOL/Lists: the function "set_of_list" has been renamed "set"

  (and its theorems too);

* HOL/Set: UNIV is now a constant and is no longer translated to Compl{};

* HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its

  specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);

*** HOLCF ***

* removed "axioms" and "generated by" sections;

* replaced "ops" section by extended "consts" section, which is capable of

  handling the continuous function space "->" directly;

* domain package:

  . proves theorems immediately and stores them in the theory,

  . creates hierachical name space,

  . now uses normal mixfix annotations (instead of cinfix...),

  . minor changes to some names and values (for consistency),

  . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,

  . separator between mutual domain defs: changed "," to "and",

  . improved handling of sort constraints;  now they have to

    appear on the left-hand side of the equations only;

* fixed LAM <x,y,zs>.b syntax;

* added extended adm_tac to simplifier in HOLCF -- can now discharge

adm (%x. P (t x)), where P is chainfinite and t continuous;

*** FOL and ZF ***

* FOL: there is a new splitter `split_asm_tac' that can be used e.g. 

  with `addloop' of the simplifier to faciliate case splitting in premises.

* qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as

in HOL, they strip ALL and --> from proved theorems;

New in Isabelle94-8 (May 1997)

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

*** General Changes ***

* new utilities to build / run / maintain Isabelle etc. (in parts

still somewhat experimental); old Makefiles etc. still functional;

* new 'Isabelle System Manual';

* INSTALL text, together with ./configure and ./build scripts;

* reimplemented type inference for greater efficiency, better error

messages and clean internal interface;

* prlim command for dealing with lots of subgoals (an easier way of

setting goals_limit);

*** Syntax ***

* supports alternative (named) syntax tables (parser and pretty

printer); internal interface is provided by add_modesyntax(_i);

* Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to

be used in conjunction with the Isabelle symbol font; uses the

"symbols" syntax table;

* added token_translation interface (may translate name tokens in

arbitrary ways, dependent on their type (free, bound, tfree, ...) and

the current print_mode); IMPORTANT: user print translation functions

are responsible for marking newly introduced bounds

(Syntax.mark_boundT);

* token translations for modes "xterm" and "xterm_color" that display

names in bold, underline etc. or colors (which requires a color

version of xterm);

* infixes may now be declared with names independent of their syntax;

* added typed_print_translation (like print_translation, but may

access type of constant);

*** Classical Reasoner ***

Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has

some limitations.  Blast_tac...

  + ignores addss, addbefore, addafter; this restriction is intrinsic

  + ignores elimination rules that don't have the correct format

	(the conclusion MUST be a formula variable)

  + ignores types, which can make HOL proofs fail

  + rules must not require higher-order unification, e.g. apply_type in ZF

    [message "Function Var's argument not a bound variable" relates to this]

  + its proof strategy is more general but can actually be slower

* substitution with equality assumptions no longer permutes other

assumptions;

* minor changes in semantics of addafter (now called addaltern); renamed

setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper

(and access functions for it);

* improved combination of classical reasoner and simplifier: 

  + functions for handling clasimpsets

  + improvement of addss: now the simplifier is called _after_ the

    safe steps.

  + safe variant of addss called addSss: uses safe simplifications

    _during_ the safe steps. It is more complete as it allows multiple 

    instantiations of unknowns (e.g. with slow_tac).

*** Simplifier ***

* added interface for simplification procedures (functions that

produce *proven* rewrite rules on the fly, depending on current

redex);

* ordering on terms as parameter (used for ordered rewriting);

* new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;

* the solver is now split into a safe and an unsafe part.

This should be invisible for the normal user, except that the

functions setsolver and addsolver have been renamed to setSolver and

addSolver; added safe_asm_full_simp_tac;

*** HOL ***

* a generic induction tactic `induct_tac' which works for all datatypes and

also for type `nat';

* a generic case distinction tactic `exhaust_tac' which works for all

datatypes and also for type `nat';

* each datatype comes with a function `size';

* patterns in case expressions allow tuple patterns as arguments to

constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';

* primrec now also works with type nat;

* recdef: a new declaration form, allows general recursive functions to be

defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.

* the constant for negation has been renamed from "not" to "Not" to

harmonize with FOL, ZF, LK, etc.;

* HOL/ex/LFilter theory of a corecursive "filter" functional for

infinite lists;

* HOL/Modelcheck demonstrates invocation of model checker oracle;

* HOL/ex/Ring.thy declares cring_simp, which solves equational

problems in commutative rings, using axiomatic type classes for + and *;

* more examples in HOL/MiniML and HOL/Auth;

* more default rewrite rules for quantifiers, union/intersection;

* a new constant `arbitrary == @x.False';

* HOLCF/IOA replaces old HOL/IOA;

* HOLCF changes: derived all rules and arities 

  + axiomatic type classes instead of classes 

  + typedef instead of faking type definitions

  + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.

  + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po

  + eliminated the types void, one, tr

  + use unit lift and bool lift (with translations) instead of one and tr

  + eliminated blift from Lift3.thy (use Def instead of blift)

  all eliminated rules are derived as theorems --> no visible changes ;

*** ZF ***

* ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default

rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back

as ZF_cs addSIs [equalityI];

New in Isabelle94-7 (November 96)

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

* allowing negative levels (as offsets) in prlev and choplev;

* super-linear speedup for large simplifications;

* FOL, ZF and HOL now use miniscoping: rewriting pushes

quantifications in as far as possible (COULD MAKE EXISTING PROOFS

FAIL); can suppress it using the command Delsimps (ex_simps @

all_simps); De Morgan laws are also now included, by default;

* improved printing of ==>  :  ~:

* new object-logic "Sequents" adds linear logic, while replacing LK

and Modal (thanks to Sara Kalvala);

* HOL/Auth: correctness proofs for authentication protocols;

* HOL: new auto_tac combines rewriting and classical reasoning (many

examples on HOL/Auth);

* HOL: new command AddIffs for declaring theorems of the form P=Q to

the rewriter and classical reasoner simultaneously;

* function uresult no longer returns theorems in "standard" format;

regain previous version by: val uresult = standard o uresult;

New in Isabelle94-6

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

* oracles -- these establish an interface between Isabelle and trusted

external reasoners, which may deliver results as theorems;

* proof objects (in particular record all uses of oracles);

* Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;

* "constdefs" section in theory files;

* "primrec" section (HOL) no longer requires names;

* internal type "tactic" now simply "thm -> thm Sequence.seq";

New in Isabelle94-5

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

* reduced space requirements;

* automatic HTML generation from theories;

* theory files no longer require "..." (quotes) around most types;

* new examples, including two proofs of the Church-Rosser theorem;

* non-curried (1994) version of HOL is no longer distributed;

New in Isabelle94-4

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

* greatly reduced space requirements;

* theory files (.thy) no longer require \...\ escapes at line breaks;

* searchable theorem database (see the section "Retrieving theorems" on 

page 8 of the Reference Manual);

* new examples, including Grabczewski's monumental case study of the

Axiom of Choice;

* The previous version of HOL renamed to Old_HOL;

* The new version of HOL (previously called CHOL) uses a curried syntax 

for functions.  Application looks like f a b instead of f(a,b);

* Mutually recursive inductive definitions finally work in HOL;

* In ZF, pattern-matching on tuples is now available in all abstractions and

translates to the operator "split";

New in Isabelle94-3

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

* new infix operator, addss, allowing the classical reasoner to 

perform simplification at each step of its search.  Example:

	fast_tac (cs addss ss)

* a new logic, CHOL, the same as HOL, but with a curried syntax 

for functions.  Application looks like f a b instead of f(a,b).  Also pairs 

look like (a,b) instead of <a,b>;

* PLEASE NOTE: CHOL will eventually replace HOL!

* In CHOL, pattern-matching on tuples is now available in all abstractions.

It translates to the operator "split".  A new theory of integers is available;

* In ZF, integer numerals now denote two's-complement binary integers.

Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;

* Many new examples: I/O automata, Church-Rosser theorem, equivalents 

of the Axiom of Choice;

New in Isabelle94-2

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

* Significantly faster resolution;  

* the different sections in a .thy file can now be mixed and repeated

freely;

* Database of theorems for FOL, HOL and ZF.  New

commands including qed, qed_goal and bind_thm store theorems in the database.

* Simple database queries: return a named theorem (get_thm) or all theorems of

a given theory (thms_of), or find out what theory a theorem was proved in

(theory_of_thm);

* Bugs fixed in the inductive definition and datatype packages;

* The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs

and HOL_dup_cs obsolete;

* Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1

have been removed;

* Simpler definition of function space in ZF;

* new results about cardinal and ordinal arithmetic in ZF;

* 'subtype' facility in HOL for introducing new types as subsets of existing

types;

$Id$