aboutsummaryrefslogtreecommitdiff
path: root/contrib/subtac/subtac_command.ml
AgeCommit message (Collapse)Author
2009-03-20Directory 'contrib' renamed into 'plugins', to end confusion with archive of ↵letouzey
user contribs git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@11996 85f007b7-540e-0410-9357-904b9bb8a0f7
2009-02-19On remplace evar_map par evar_defs (seul evar_defs est désormais exporté aspiwack
par Evd). Ça s'accompagne de quelques autres modifications de l'interface (certaines fonctions étaient des doublons, ou des conversions entre evar_map et evar_defs). J'ai modifié un peu la structure de evd.ml aussi, pour éviter des fonctions redéfinies deux fois (i.e. définies trois fois !), j'ai introduit des sous-modules pour les différentes couches. Il y a à l'heure actuelle une pénalité en performance assez sévère (due principalement à la nouvelle mouture de Evd.merge, si mon diagnostique est correct). Mais fera l'objet de plusieurs optimisations dans les commits à venir. Un peu plus ennuyeux, la test-suite du mode déclaratif ne passe plus. Un appel de Decl_proof_instr.mark_as_done visiblement, je suis pour l'instant incapable de comprendre ce qui cause cette erreur. J'espère qu'on pourra le déterminer rapidement. Ce commit est le tout premier commit dans le trunk en rapport avec les évolution futures de la machine de preuve, en vue en particulier d'obtenir un "vrai refine". git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@11939 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-11-09More factorization of inductive/record and typeclasses: move classmsozeau
declaration code to toplevel/record, including support for singleton classes as definitions. Parsing code also factorized. Arnaud: one more thing to think about when refactoring the definitions in vernacentries. Add support for specifying what to do with anonymous variables in contexts during internalisation (fixes bug #1982), current choice is to generate a name for typeclass bindings. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@11563 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-09-11Add enough information to correctly globalize recursive calls in inductive andmsozeau
recursive definitions and references to previous fields in record and classes definitions. Fixes the corresponding typesetting issue in coqdoc output. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@11397 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-09-07Better handling of the opacity of proof obligations, add the possibility ofmsozeau
overriding the default tactic when adding a definition. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@11373 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-07-24Fix bug #1913, checking for unresolved evars which aren't obligations.msozeau
Also check mutuality of fixpoints. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@11257 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-05-30Improvements on coqdoc by adding more information into .globmsozeau
files, about definitions and type of references. - Add missing location information on fixpoints/cofixpoint in topconstr and syntactic definitions in vernacentries for correct dumping. - Dump definition information in vernacentries: defs, constructors, projections etc... - Modify coqdoc/index.mll to use this information instead of trying to scan the file. - Use the type information in latex output, update coqdoc.sty accordingly. - Use the hyperref package to do crossrefs between definition and references to coq objects in latex. Next step is to test and debug it on bigger developments. On the side: - Fix Program Let which was adding a Global definition. - Correct implicits for well-founded Program Fixpoints. - Add new [Method] declaration kind. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@11024 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-05-13- Fix bug related to indices of fixpoints.msozeau
- Add a typeclasses_eauto which uses only the typeclass_instances database. - Set obligations as transparent by default to avoid the common problem with ill-formed recursive defs due to opaque obligations. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10925 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-05-06Postpone the search for the recursive argument index from the user givenmsozeau
name after internalisation, to get the correct behavior with typeclass binders. This simplifies the pretty printing and translation of the recursive argument name in various places too. Use this opportunity to factorize the different internalization and interpretation functions of binders as well. This definitely fixes part 2 of bug #1846 and makes it possible to use fixpoint definitions with typeclass arguments in program too, with an example given in EquivDec. At the same time, one fix and one enhancement in Program: - fix a de Bruijn bug in subtac_cases - introduce locations of obligations and use them in case the obligation tactic raises a failure when tried on a particular obligation, as suggested by Sean Wilson. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10889 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-04-07Fix big de Bruijn bug in mutually recursive definitions.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10763 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-03-16Removed unneeded tactics from RelationClasses. Usemsozeau
check_required_library where needed (fixes bug #1797). Remove spurious messages from ring when not in verbose mode. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10685 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-03-15Do a second pass on the treatment of user-given implicit arguments. Nowmsozeau
works in inductive type definitions and fixpoints. The semantics of an implicit inductive parameter is maybe a bit weird: it is implicit in the inductive definition of constructors and the contructor types but not in the inductive type itself (ie. to model the fact that one rarely wants A in vector A n to be implicit but in vnil yes). Example in test-suite/ Also, correct the handling of the implicit arguments across sections. Every definition which had no explicitely given implicit arguments was treated as if we asked to do global automatic implicit arguments on section closing. Hence some arguments were given implicit status for no apparent reason. Also correct and test the parsing rule which disambiguates between {wf ..} and {A ..}. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10677 85f007b7-540e-0410-9357-904b9bb8a0f7
2008-02-08Backport code from command.ml to subtac_command.ml for defininingmsozeau
recursive definitions. Now program accepts cofixpoints and uses the new way infer structurally decreasing arguments. Also, checks for correct recursive calls before giving the definition to the obligations machine (solves part 1 of bug #1784). git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10529 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-12-31Merged revisions ↵msozeau
10358-10362,10365,10371-10373,10377,10383-10384,10394-10395,10398,10403-10408 via svnmerge from svn+ssh://msozeau@scm.gforge.inria.fr/svn/coq/branches/TypeClasses ........ r10358 | msozeau | 2007-12-10 15:42:53 +0100 (Mon, 10 Dec 2007) | 1 line Comment grammar error ........ r10359 | msozeau | 2007-12-10 16:04:09 +0100 (Mon, 10 Dec 2007) | 7 lines The initial Type Classes patch. This patch introduces type classes and instance definitions a la Haskell. Technically, it uses the implicit arguments mechanism which was extended a bit. The patch also introduces a notation for explicitely marking implicit, maximally inserted parameters. It includes the tactic redefinition code too (Ltac tac ::= foo redefines tac). ........ r10360 | msozeau | 2007-12-10 16:14:30 +0100 (Mon, 10 Dec 2007) | 1 line Fix interface ........ r10361 | msozeau | 2007-12-10 16:28:19 +0100 (Mon, 10 Dec 2007) | 1 line Fix more xlate code ........ r10362 | msozeau | 2007-12-11 02:00:53 +0100 (Tue, 11 Dec 2007) | 3 lines Update coqdoc for type classes, fix proof state not being displayed on Next Obligation. ........ r10365 | msozeau | 2007-12-11 14:22:35 +0100 (Tue, 11 Dec 2007) | 3 lines Bug fixes in Instance decls. ........ r10371 | msozeau | 2007-12-12 21:17:30 +0100 (Wed, 12 Dec 2007) | 3 lines Streamline typeclass context implementation, prepare for class binders in proof statements. ........ r10372 | msozeau | 2007-12-12 22:03:38 +0100 (Wed, 12 Dec 2007) | 1 line Minor cosmetic fixes: allow sorts as typeclass param instances without parens and infer more types in class definitions ........ r10373 | msozeau | 2007-12-13 00:35:09 +0100 (Thu, 13 Dec 2007) | 2 lines Better names in g_vernac, binders in Lemmas and Context [] to introduce a typeclass context. ........ r10377 | msozeau | 2007-12-13 18:34:33 +0100 (Thu, 13 Dec 2007) | 1 line Stupid bug ........ r10383 | msozeau | 2007-12-16 00:04:48 +0100 (Sun, 16 Dec 2007) | 1 line Bug fixes in name handling and implicits, new syntax for using implicit mode in typeclass constraints ........ r10384 | msozeau | 2007-12-16 15:53:24 +0100 (Sun, 16 Dec 2007) | 1 line Streamlined implementation of instances again, the produced typeclass is a typeclass constraint. Added corresponding implicit/explicit behaviors ........ r10394 | msozeau | 2007-12-18 23:42:56 +0100 (Tue, 18 Dec 2007) | 4 lines Various fixes for implicit arguments, new "Enriching" kw to just enrich existing sets of impl args. New syntax !a to force an argument, even if not dependent. New tactic clrewrite using a setoid typeclass implementation to do setoid_rewrite under compatible morphisms... very experimental. Other bugs related to naming in typeclasses fixed. ........ r10395 | msozeau | 2007-12-19 17:11:55 +0100 (Wed, 19 Dec 2007) | 3 lines Progress on setoids using type classes, recognize setoid equalities in hyps better. Streamline implementation to return more information when resolving setoids (return the results setoid). ........ r10398 | msozeau | 2007-12-20 10:18:19 +0100 (Thu, 20 Dec 2007) | 1 line Syntax change, more like Coq ........ r10403 | msozeau | 2007-12-21 22:30:35 +0100 (Fri, 21 Dec 2007) | 1 line Add right-to-left rewriting in class_setoid, fix some discharge/substitution bug, adapt test-suite to latest syntax ........ r10404 | msozeau | 2007-12-24 21:47:58 +0100 (Mon, 24 Dec 2007) | 2 lines Work on type classes based rewrite tactic. ........ r10405 | msozeau | 2007-12-27 18:51:32 +0100 (Thu, 27 Dec 2007) | 2 lines Better evar handling in pretyping, reorder theories/Program and add some tactics for dealing with subsets. ........ r10406 | msozeau | 2007-12-27 18:52:05 +0100 (Thu, 27 Dec 2007) | 1 line Forgot to add a file ........ r10407 | msozeau | 2007-12-29 17:19:54 +0100 (Sat, 29 Dec 2007) | 4 lines Generalize usage of implicit arguments in terms, up to rawconstr. Binders are decorated with binding info, either Implicit or Explicit for rawconstr. Factorizes code for typeclasses, topconstrs decorations are Default (impl|expl) or TypeClass (impl|expl) and implicit quantification is resolve at internalization time, getting rid of the arbitrary prenex restriction on contexts. ........ r10408 | msozeau | 2007-12-31 00:58:50 +0100 (Mon, 31 Dec 2007) | 4 lines Fix parsing of subset binders, bugs in subtac_cases and handling of mutual defs obligations. Add useful tactics to Program.Subsets. ........ git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10410 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-12-06Plus de combinateurs sont passés de Util à Option. Le module Options aspiwack
devient Flags. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10348 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-12-05Factorisation des opérations sur le type option de Util dans un module aspiwack
lib/option.ml(i) . J'en profite pour rajouter des primitives de lifting des fonctions (à un ou deux arguments tous ou partie de type option). Il reste quelques opérations dans Util à propos desquelles je ne suis pas trop sûr, ou simplement que j'ai oublié, mais qui attendront demain car il est tard (comme some_in qui devrait devenir Option.make je suppose) . Elles s'expriment souvent facilement en fonction des autres, par exemple "option_compare x y" est égal à "Option.lift2 compare x y" . Le option_cons devrait faire son chemin dans le module parce qu'il est assez primitif et qu'il n'y a pas de fonction "cons" dans OCaml. J'en ai profité aussi pour remplacer les trop nombreux "failwith" par des erreurs locales au module, donc plus robustes. J'ai trouvé aussi une fonction qui était définie deux fois, et une définie dans un module particulier. Mon seul bémol (mais facile à traiter) c'est la proximité entre le nom de module Option et l'ancien Options. J'ai pas de meilleure idée de nom à l'heure qu'il est, ni pour l'un, ni pour l'autre. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10346 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-11-08Prise en compte des notations "alias" dans la globalisation des coercions.herbelin
Au passage, un peu plus de standardisation des noms de fonctions de globalisation Principe de base : locate_foo : qualid -> foo (échoue avec Not_found) global : reference -> global_reference (échoue avec UserError) global_of_foo : foo -> global_reference (échoue avec UserError) f_with_alias : se comporte comme f mais prenant aussi en compte les notations de la forme "Notation id:=ref" Principale exception : locate, au lieu de locate_global locate_global_with_alias, qui prend en entrée un "qualid located" Restent beaucoup de fonctions qui pourraient utiliser global_with_alias au lieu de global, notamment dans contribs. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10305 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-10-24Fix some bugs, add possibility of automatically solving a proof statement's ↵msozeau
obligations and start the proof afterwards. Changes the architecture of subtac_obligations a bit. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10257 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-08-26Fix bug on wellfounded defs with constant parameters and dependencies on the ↵msozeau
rec argument, example given by Brian Aydemir. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10097 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-08-26Fix de Bruijn bug in wf definitions.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10096 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-08-26Fix evars bug in mutual fixpoints with implicit types and bug in ↵msozeau
inequalities generation for multiple patterns. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10094 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-07-19Documentation of Program and its tactics, fix enormous interaction bug due ↵msozeau
to bad cache handling. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10032 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-04-17Correct implementation of undo in obligations handling code, correct some ↵msozeau
bugs in pattern-matching compilation with multiple matched objects. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9783 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-03-28Support for implicit formal argument types in Program ; parse types in type ↵msozeau
scope. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9734 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-03-19Add a parameter to QuestionMark evar kind to say it can be turned into an ↵msozeau
obligations (even an opaque one). Change cast_type to include the converted-to type or nothing in case of a Coerce cast, required much minor changes. Various little subtac changes. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9718 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-02-27Fix wf bug from F. Besson and work on ineqs generation.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9682 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-02-23Debug wellfounded defs, work on cleaning obls envsmsozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9674 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-02-19Various little subtac fixes, add some useful tactics.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9659 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-02-13Réactivation du filtrage d'ordre 2 dans ltac qui avait cessé deherbelin
fonctionner entre la V7.3 et la V8.0 (notation : "@ ?meta id1 ... idn") git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9644 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-02-07Various subtac fixes. Add inequalities in pattern matching branches when ↵msozeau
needed, handle undo for the default tactic... git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9608 85f007b7-540e-0410-9357-904b9bb8a0f7
2007-01-15Various subtac fixes.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9485 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-12-08Subtac bug fix, add list take example.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9411 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-11-10Work on mutual defs, various bug fixes.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9360 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-11-10Work on pattern inequalities for pattern matching branches.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9358 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-11-09Support for mutual defs in obligation handling.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9357 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-10-31Work on obligation separation.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9326 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-10-26Facilities to automatically solve obligationsmsozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9284 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-10-10Fix 0 obligations bugmsozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9231 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-09-01New handling of obligations.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9120 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-09-01Subtac fixes, new way of handling obligations in progress.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9117 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-06-22Mutually structurally recursive defs and rec using measures added.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8968 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-06-20Wellfounded recursion using subtac working again.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8966 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-06-20Progress in new wf def typing.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8965 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-06-20Rewrite of the recursive defs handling in progress.msozeau
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8964 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-06-01Fix some nasty bug with the evars-to-dependent sum encoding.msozeau
Also enclose traces with try with clauses to avoid detypinging anomalies. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8889 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-05-29The "clean integration of subtac" patch.msozeau
Adds a new kind of casts (CastCoerce) for coercing an object to its base type (e.g. inductive). The new cast_type type subsumes usual casts ConvCasts. Much of the patch is just adding ConvCasts where needed. The Pretyping module has been adapted to this change, although it doesn't change anything yet, but this construct could have a use with current coercions also. Pretyping is also cleaned from the "Use type constraints under lambdas" patch which is not yet ready for wide use. It has been transferred to a copy of the Pretyping Functor in subtac_pretyping_F.ml. Subtac is now working as well as I demonstrated at TYPES. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8875 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-04-27Standardisation nom option_app en option_mapherbelin
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8752 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-04-14Si un fixpoint a plusieurs arguments, mais un seul de type inductif, letouzey
ce patch dispense d'ecrire le { struct .. } En pratique, dans Topconstr.fixpoint_expr et Rawterm.fix_kind, l'index de l'argument inductif devient un int option au lieu d'un int. Les deux cas possibles: - Some n : les situations autorisées auparavant, a savoir {struct} explicite, ou bien un seul argument au total - None : le cas nouveau, qui redonne un entier lors du passage de rawconstr à constr si l'on trouve effectivement un unique argument ayant un type inductif, et une erreur sinon. Pour l'instant, on cherche l'inductif dans le type de manière syntaxique, mais il est jouable de rajouter un poil de reduction (au moins delta). Dans le détail, voici les coins que ce patch influence: - parsing/g_xml.ml4: continue pour l'instant a attendre un index explicite via un element xml "recIndex" - contrib/interface/xlate.ml: a priori ca marche, car il y avait déjà un cas ctv_ID_OPT_NONE correspondant à l'absence de struct. Par contre, dans le détail, le code pour un CFix utilise l'index de recurrence pour recouper au besoin le type du fixpoint en deux. Est-ce que je me gourre en supposant que si l'on a besoin de couper ainsi ce type, c'est qu'il provient non pas du parseur Coq, mais de l'impression d'un constr, et donc que l'index aura été correctement résolu ? - contrib/subtac/subtac_command.ml: - contrib/funind/indfun.ml: dans les deux cas, j'ai fait le service minimum, le struct reste obligatoire s'il y a plusieurs arguments. Mais ca ne serait pas dur à adapter pour ceux qui comprennent ces parties. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8718 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-04-10Actual fix for the unification problem in theories/Reals/Rtrigo_fun ↵msozeau
(previous and current version work). Changed the type of typing constraints so as to have all the necessary information on abstract tycons. Updates of subtac to use the new type. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8693 85f007b7-540e-0410-9357-904b9bb8a0f7
2006-04-07- Documentation of the Program tactics.msozeau
- Fixes to the subtac implementation, utility tactic to apply existentials to a function and build a dependent sum out of name, constr lists. Also defined a Utils coq module for tactics related to subsets and the projections for ex in Prop. - Enhancements to inference algorithm added but not used in the default version as there are some remaining bugs. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@8688 85f007b7-540e-0410-9357-904b9bb8a0f7