Here comes the commit, announced long ago, of the new tactic engine.

This is a fairly large commit (around 140 files and 7000 lines of code
impacted), it will cause some troubles for sure (I've listed the know
regressions below, there is bound to be more).
At this state of developpement it brings few features to the user, as
the old tactics were
ported with no change. Changes are on the side of the developer mostly.

Here comes a list of the major changes. I will stay brief, but the code
is hopefully well documented so that it is reasonably easy to infer the
details from it.

Feature developer-side:
* Primitives for a "real" refine tactic (generating a goal for each
evar).
* Abstract type of tactics, goals and proofs
* Tactics can act on several goals (formally all the focused goals). An
interesting consequence of this is that the tactical (. ; [ . | ... ])
can be separated in two
tacticals (. ; .) and ( [ . | ... ] ) (although there is a conflict for
this particular syntax). We can also imagine a tactic to reorder the
goals.
* Possibility for a tactic to pass a value to following tactics (a
typical example is
an intro function which tells the following tactics which name it
introduced).
* backtracking primitives for tactics (it is now possible to implement a
tactical '+'
  with (a+b);c equivalent to (a;c+b;c) (itself equivalent to
(a;c||b;c)). This is a valuable
  tool to implement tactics like "auto" without nowing of the
implementation of tactics.
* A notion of proof modes, which allows to dynamically change the parser
for tactics. It is controlled at user level with the keywords Set
Default Proof Mode (this is the proof mode which is loaded at the start
of each proof) and Proof Mode (switches the proof mode of the current
proof) to control them.
* A new primitive Evd.fold_undefined which operates like an Evd.fold,
except it only goes through the evars whose body is Evar_empty. This is
a common operation throughout the code,
some of the fold-and-test-if-empty occurences have been replaced by
fold_undefined. For now,
it is only implemented as a fold-and-test, but we expect to have some
optimisations coming some day, as there can be a lot of evars in an
evar_map with this new implementation (I've observed a couple of
thousands), whereas there are rarely more than a dozen undefined ones.
Folding being a linear operation, this might result in a significant
speed-up.
* The declarative mode has been moved into the plugins. This is made
possible by the proof mode feature. I tried to document it so that it
can serve as a tutorial for a tactic mode plugin.

Features user-side:
* Unfocus does not go back to the root of the proof if several Focus-s
have been performed.
  It only goes back to the point where it was last focused.
* experimental (non-documented) support of keywords
BeginSubproof/EndSubproof:
  BeginSubproof focuses on first goal, one can unfocus only with
EndSubproof, and only
  if the proof is completed for that goal.
* experimental (non-documented) support for bullets ('+', '-' and '*')
  they act as hierarchical BeginSubproof/EndSubproof:
  First time one uses '+' (for instance) it focuses on first goal, when
the subproof is
  completed, one can use '+' again which unfocuses and focuses on next
first goal.
  Meanwhile, one cas use '*' (for instance) to focus more deeply.

Known regressions:
* The xml plugin had some functions related to proof trees. As the
structure of proof changed significantly, they do not work anymore.
* I do not know how to implement info or show script in this new engine.
Actually I don't even know what they were suppose to actually mean in
earlier versions either. I wager they would require some calm thinking
before going back to work.
* Declarative mode not entirely working (in particular proofs by
induction need to be restored).
* A bug in the inversion tactic (observed in some contributions)
* A bug in Program (observed in some contributions)
* Minor change in the 'old' type of tactics causing some contributions
to fail.
* Compilation time takes about 10-15% longer for unknown reasons (I
suspect it might be linked to the fact that I don't perform any
reduction at QED-s, and also to some linear operations on evar_map-s
(see Evd.fold_undefined above)).


git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@12961 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 472 insertions, 0 deletions

diff --git a/plugins/decl_mode/decl_interp.ml b/plugins/decl_mode/decl_interp.ml
new file mode 100644
index 0000000000..2b583af407
--- /dev/null
+++ b/plugins/decl_mode/decl_interp.ml
@@ -0,0 +1,472 @@
+(************************************************************************)
+(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
+(* <O___,, * CNRS-Ecole Polytechnique-INRIA Futurs-Universite Paris Sud *)
+(*   \VV/  **************************************************************)
+(*    //   *      This file is distributed under the terms of the       *)
+(*         *       GNU Lesser General Public License Version 2.1        *)
+(************************************************************************)
+
+(*i $Id$ i*)
+
+open Util
+open Names
+open Topconstr
+open Tacinterp
+open Tacmach
+open Decl_expr
+open Decl_mode
+open Pretyping.Default
+open Rawterm
+open Term
+open Pp
+
+(* INTERN *)
+
+let raw_app (loc,hd,args) = if args =[] then hd else RApp(loc,hd,args)
+
+let intern_justification_items globs =
+  Option.map (List.map (intern_constr globs))
+
+let intern_justification_method globs =
+  Option.map (intern_tactic globs)
+
+let intern_statement intern_it globs st =
+  {st_label=st.st_label;
+   st_it=intern_it globs st.st_it}
+
+let intern_no_bind intern_it globs x =
+  globs,intern_it globs x
+
+let intern_constr_or_thesis globs = function
+    Thesis n -> Thesis n
+  | This c -> This (intern_constr globs c)
+
+let add_var id globs=
+  let l1,l2=globs.ltacvars in
+    {globs with ltacvars= (id::l1),(id::l2)}
+
+let add_name nam globs=
+ match nam with
+     Anonymous -> globs
+   | Name id -> add_var id globs
+
+let intern_hyp iconstr globs = function
+    Hvar (loc,(id,topt)) -> add_var id globs,
+      Hvar (loc,(id,Option.map (intern_constr globs) topt))
+  | Hprop st -> add_name st.st_label globs,
+      Hprop (intern_statement iconstr globs st)
+
+let intern_hyps iconstr globs hyps =
+  snd (list_fold_map (intern_hyp iconstr) globs hyps)
+
+let intern_cut intern_it globs cut=
+  let nglobs,nstat=intern_it globs cut.cut_stat in
+    {cut_stat=nstat;
+     cut_by=intern_justification_items nglobs cut.cut_by;
+     cut_using=intern_justification_method nglobs cut.cut_using}
+
+let intern_casee globs = function
+    Real c -> Real (intern_constr globs c)
+  | Virtual cut -> Virtual
+      (intern_cut (intern_no_bind (intern_statement intern_constr)) globs cut)
+
+let intern_hyp_list args globs =
+  let intern_one globs (loc,(id,opttyp)) =
+    (add_var id globs),
+    (loc,(id,Option.map (intern_constr globs) opttyp)) in
+  list_fold_map intern_one globs args
+
+let intern_suffices_clause globs (hyps,c) =
+  let nglobs,nhyps = list_fold_map (intern_hyp intern_constr) globs hyps in
+    nglobs,(nhyps,intern_constr_or_thesis nglobs c)
+
+let intern_fundecl args body globs=
+  let nglobs,nargs = intern_hyp_list args globs in
+    nargs,intern_constr nglobs body
+
+let rec add_vars_of_simple_pattern globs = function
+    CPatAlias (loc,p,id) ->
+      add_vars_of_simple_pattern (add_var id globs) p
+(*      Stdpp.raise_with_loc loc
+	(UserError ("simple_pattern",str "\"as\" is not allowed here"))*)
+  | CPatOr (loc, _)->
+      Stdpp.raise_with_loc loc
+	(UserError ("simple_pattern",str "\"(_ | _)\" is not allowed here"))
+  | CPatDelimiters (_,_,p) ->
+      add_vars_of_simple_pattern globs p
+  | CPatCstr (_,_,pl) ->
+      List.fold_left add_vars_of_simple_pattern globs pl
+  | CPatNotation(_,_,(pl,pll)) ->
+      List.fold_left add_vars_of_simple_pattern globs (List.flatten (pl::pll))
+  | CPatAtom (_,Some (Libnames.Ident (_,id))) -> add_var id globs
+  |  _  -> globs
+
+let rec intern_bare_proof_instr globs = function
+    Pthus i -> Pthus (intern_bare_proof_instr globs i)
+  | Pthen i -> Pthen (intern_bare_proof_instr globs i)
+  | Phence i -> Phence (intern_bare_proof_instr globs i)
+  | Pcut c -> Pcut
+      (intern_cut
+	 (intern_no_bind (intern_statement intern_constr_or_thesis)) globs c)
+  | Psuffices c ->
+      Psuffices (intern_cut intern_suffices_clause globs c)
+  | Prew (s,c) -> Prew
+      (s,intern_cut
+	 (intern_no_bind  (intern_statement intern_constr)) globs c)
+  | Psuppose hyps -> Psuppose (intern_hyps intern_constr globs hyps)
+  | Pcase (params,pat,hyps) ->
+      let nglobs,nparams = intern_hyp_list params globs in
+      let nnglobs= add_vars_of_simple_pattern nglobs pat in
+      let nhyps = intern_hyps intern_constr_or_thesis nnglobs hyps in
+	Pcase (nparams,pat,nhyps)
+  | Ptake witl -> Ptake (List.map (intern_constr globs) witl)
+  | Pconsider (c,hyps) -> Pconsider (intern_constr globs c,
+				      intern_hyps intern_constr globs hyps)
+  | Pper (et,c) -> Pper (et,intern_casee globs c)
+  | Pend bt -> Pend bt
+  | Pescape -> Pescape
+  | Passume hyps -> Passume (intern_hyps intern_constr globs hyps)
+  | Pgiven hyps -> Pgiven (intern_hyps intern_constr globs hyps)
+  | Plet hyps -> Plet (intern_hyps intern_constr globs hyps)
+  | Pclaim st -> Pclaim (intern_statement intern_constr globs st)
+  | Pfocus st -> Pfocus (intern_statement intern_constr globs st)
+  | Pdefine (id,args,body) ->
+      let nargs,nbody = intern_fundecl args body globs in
+	Pdefine (id,nargs,nbody)
+  | Pcast (id,typ) ->
+      Pcast (id,intern_constr globs typ)
+
+let rec intern_proof_instr globs instr=
+  {emph = instr.emph;
+   instr = intern_bare_proof_instr globs instr.instr}
+
+(* INTERP *)
+
+let interp_justification_items sigma env =
+    Option.map (List.map (fun c ->understand sigma env (fst c)))
+
+let interp_constr check_sort sigma env c =
+  if check_sort then
+    understand_type sigma env (fst c)
+  else
+    understand sigma env (fst c)
+
+let special_whd env =
+  let infos=Closure.create_clos_infos Closure.betadeltaiota env in
+    (fun t -> Closure.whd_val infos (Closure.inject t))
+
+let _eq = Libnames.constr_of_global (Coqlib.glob_eq)
+
+let decompose_eq env id =
+  let typ = Environ.named_type id env in
+  let whd = special_whd env typ in
+    match kind_of_term whd with
+	App (f,args)->
+	  if eq_constr f _eq && (Array.length args)=3
+	  then args.(0)
+	  else error "Previous step is not an equality."
+      | _ -> error "Previous step is not an equality."
+
+let get_eq_typ info env =
+  let typ = decompose_eq env (get_last env) in
+    typ
+
+let interp_constr_in_type typ sigma env c =
+  understand sigma env (fst c) ~expected_type:typ
+
+let interp_statement interp_it sigma env st =
+  {st_label=st.st_label;
+   st_it=interp_it sigma env st.st_it}
+
+let interp_constr_or_thesis check_sort sigma env = function
+    Thesis n -> Thesis n
+  | This c -> This (interp_constr check_sort sigma env c)
+
+let abstract_one_hyp inject h raw =
+  match h with
+      Hvar (loc,(id,None)) ->
+	RProd (dummy_loc,Name id, Explicit, RHole (loc,Evd.BinderType (Name id)), raw)
+    | Hvar (loc,(id,Some typ)) ->
+	RProd (dummy_loc,Name id, Explicit, fst typ, raw)
+    | Hprop st ->
+	RProd (dummy_loc,st.st_label, Explicit, inject st.st_it, raw)
+
+let rawconstr_of_hyps inject hyps head =
+  List.fold_right (abstract_one_hyp inject) hyps head
+
+let raw_prop = RSort (dummy_loc,RProp Null)
+
+let rec match_hyps blend names constr = function
+    [] -> [],substl names constr
+  | hyp::q ->
+      let (name,typ,body)=destProd constr in
+      let st= {st_label=name;st_it=substl names typ} in
+      let qnames=
+	match name with
+	    Anonymous -> mkMeta 0 :: names
+	  | Name id -> mkVar id :: names in
+      let qhyp = match hyp with
+	  Hprop st' -> Hprop (blend st st')
+	| Hvar _ -> Hvar st in
+      let rhyps,head = match_hyps blend qnames body q in
+	qhyp::rhyps,head
+
+let interp_hyps_gen inject blend sigma env hyps head =
+  let constr=understand sigma env (rawconstr_of_hyps inject hyps head) in
+    match_hyps blend [] constr hyps
+
+let interp_hyps sigma env hyps = fst (interp_hyps_gen fst (fun x _ -> x) sigma env hyps raw_prop)
+
+let dummy_prefix= id_of_string "__"
+
+let rec deanonymize ids =
+  function
+      PatVar (loc,Anonymous) ->
+	let (found,known) = !ids in
+	let new_id=Namegen.next_ident_away dummy_prefix known in
+	let _= ids:= (loc,new_id) :: found , new_id :: known in
+	  PatVar (loc,Name new_id)
+    | PatVar (loc,Name id) as pat ->
+	let (found,known) = !ids in
+	let _= ids:= (loc,id) :: found , known in
+	  pat
+    | PatCstr(loc,cstr,lpat,nam) ->
+	PatCstr(loc,cstr,List.map (deanonymize ids) lpat,nam)
+
+let rec raw_of_pat =
+  function
+      PatVar (loc,Anonymous) -> anomaly "Anonymous pattern variable"
+    | PatVar (loc,Name id) ->
+	  RVar (loc,id)
+    | PatCstr(loc,((ind,_) as cstr),lpat,_) ->
+	let mind= fst (Global.lookup_inductive ind) in
+	let rec add_params n q =
+	  if n<=0 then q else
+	    add_params (pred n) (RHole(dummy_loc,
+				       Evd.TomatchTypeParameter(ind,n))::q) in
+	    let args = List.map raw_of_pat lpat in
+	      raw_app(loc,RRef(dummy_loc,Libnames.ConstructRef cstr),
+		   add_params mind.Declarations.mind_nparams args)
+
+let prod_one_hyp = function
+    (loc,(id,None)) ->
+      (fun raw ->
+	 RProd (dummy_loc,Name id, Explicit,
+		RHole (loc,Evd.BinderType (Name id)), raw))
+  | (loc,(id,Some typ)) ->
+      (fun raw ->
+	 RProd (dummy_loc,Name id, Explicit, fst typ, raw))
+
+let prod_one_id (loc,id) raw =
+  RProd (dummy_loc,Name id, Explicit,
+	 RHole (loc,Evd.BinderType (Name id)), raw)
+
+let let_in_one_alias (id,pat) raw =
+  RLetIn (dummy_loc,Name id, raw_of_pat pat, raw)
+
+let rec bind_primary_aliases map pat =
+  match pat with
+      PatVar (_,_) -> map
+    | PatCstr(loc,_,lpat,nam) ->
+	let map1 =
+	  match nam with
+	      Anonymous -> map
+	    | Name id -> (id,pat)::map
+	in
+	  List.fold_left bind_primary_aliases map1 lpat
+
+let bind_secondary_aliases map subst =
+  List.fold_left (fun map (ids,idp) -> (ids,List.assoc idp map)::map) map subst
+
+let bind_aliases patvars subst patt =
+  let map = bind_primary_aliases [] patt in
+  let map1 = bind_secondary_aliases map subst in
+  List.rev map1
+
+let interp_pattern env pat_expr =
+  let patvars,pats = Constrintern.intern_pattern env pat_expr in
+    match pats with
+	[] -> anomaly "empty pattern list"
+      | [subst,patt] ->
+	  (patvars,bind_aliases patvars subst patt,patt)
+      | _  -> anomaly "undetected disjunctive pattern"
+
+let rec match_args dest names constr = function
+    [] -> [],names,substl names constr
+  | _::q ->
+      let (name,typ,body)=dest constr in
+      let st={st_label=name;st_it=substl names typ} in
+      let qnames=
+	match name with
+	    Anonymous -> assert  false
+	  | Name id -> mkVar id :: names in
+      let args,bnames,body = match_args dest qnames body q in
+	st::args,bnames,body
+
+let rec match_aliases names constr = function
+    [] -> [],names,substl names constr
+  | _::q ->
+      let (name,c,typ,body)=destLetIn constr in
+      let st={st_label=name;st_it=(substl names c,substl names typ)} in
+      let qnames=
+	match name with
+	    Anonymous -> assert false
+	  | Name id -> mkVar id :: names in
+      let args,bnames,body = match_aliases qnames body q in
+	st::args,bnames,body
+
+let detype_ground c = Detyping.detype false [] [] c
+
+let interp_cases info sigma env params (pat:cases_pattern_expr) hyps =
+  let et,pinfo =
+    match info.pm_stack with
+	Per(et,pi,_,_)::_ -> et,pi
+      | _ -> error "No proof per cases/induction/inversion in progress." in
+  let mib,oib=Global.lookup_inductive  pinfo.per_ind in
+  let num_params = pinfo.per_nparams in
+  let _ =
+    let expected = mib.Declarations.mind_nparams - num_params in
+      if List.length params <> expected then
+	errorlabstrm "suppose it is" 
+	  (str "Wrong number of extra arguments: " ++ 
+	     (if expected = 0 then str "none" else int expected) ++ spc () ++
+	     str "expected.") in
+  let app_ind =
+    let rind = RRef (dummy_loc,Libnames.IndRef pinfo.per_ind) in
+    let rparams = List.map detype_ground pinfo.per_params in
+    let rparams_rec =
+      List.map
+	(fun (loc,(id,_)) ->
+	   RVar (loc,id)) params in
+    let dum_args=
+      list_tabulate (fun _ -> RHole (dummy_loc,Evd.QuestionMark (Evd.Define false)))
+	oib.Declarations.mind_nrealargs in
+      raw_app(dummy_loc,rind,rparams@rparams_rec@dum_args) in
+  let pat_vars,aliases,patt = interp_pattern env pat in
+  let inject = function
+      Thesis (Plain) -> Rawterm.RSort(dummy_loc,RProp Null)
+    | Thesis (For rec_occ) ->
+	if not (List.mem rec_occ pat_vars) then
+	  errorlabstrm "suppose it is"
+	    (str "Variable " ++ Nameops.pr_id rec_occ ++
+	       str " does not occur in pattern.");
+	Rawterm.RSort(dummy_loc,RProp Null)
+    | This (c,_) -> c in
+  let term1 = rawconstr_of_hyps inject hyps raw_prop in
+  let loc_ids,npatt =
+    let rids=ref ([],pat_vars) in
+    let npatt= deanonymize rids patt in
+      List.rev (fst !rids),npatt in
+  let term2 =
+    RLetIn(dummy_loc,Anonymous,
+	   RCast(dummy_loc,raw_of_pat npatt,
+		 CastConv (DEFAULTcast,app_ind)),term1) in
+  let term3=List.fold_right let_in_one_alias aliases term2 in
+  let term4=List.fold_right prod_one_id loc_ids term3 in
+  let term5=List.fold_right prod_one_hyp params term4 in
+  let constr = understand  sigma env term5 in
+  let tparams,nam4,rest4 = match_args destProd [] constr params in
+  let tpatvars,nam3,rest3 = match_args destProd nam4 rest4 loc_ids in
+  let taliases,nam2,rest2 = match_aliases nam3 rest3 aliases in
+  let (_,pat_pat,pat_typ,rest1) = destLetIn rest2 in
+  let blend st st' =
+    match st'.st_it with
+	Thesis nam -> {st_it=Thesis nam;st_label=st'.st_label}
+      | This _ -> {st_it = This st.st_it;st_label=st.st_label} in
+  let thyps = fst (match_hyps blend nam2 (Termops.pop rest1) hyps) in
+    tparams,{pat_vars=tpatvars;
+	     pat_aliases=taliases;
+	     pat_constr=pat_pat;
+	     pat_typ=pat_typ;
+	     pat_pat=patt;
+	     pat_expr=pat},thyps
+
+let interp_cut interp_it sigma env cut=
+  let nenv,nstat = interp_it sigma env cut.cut_stat in
+    {cut with
+       cut_stat=nstat;
+       cut_by=interp_justification_items sigma nenv cut.cut_by}
+
+let interp_no_bind interp_it sigma env x =
+  env,interp_it sigma env x
+
+let interp_suffices_clause sigma env (hyps,cot)=
+  let (locvars,_) as res =
+    match cot with
+	This (c,_) ->
+	  let nhyps,nc = interp_hyps_gen fst (fun x _ -> x) sigma env hyps c in
+	  nhyps,This nc
+      | Thesis Plain as th  -> interp_hyps sigma env hyps,th
+      | Thesis (For n) -> error "\"thesis for\" is not applicable here." in
+  let push_one hyp env0 =
+    match hyp with
+	(Hprop st | Hvar st) ->
+	  match st.st_label with
+	      Name id -> Environ.push_named (id,None,st.st_it) env0
+	    | _ -> env in
+  let nenv = List.fold_right push_one locvars env in
+    nenv,res
+
+let interp_casee sigma env = function
+    Real c -> Real (understand sigma env (fst c))
+  | Virtual cut -> Virtual (interp_cut (interp_no_bind (interp_statement (interp_constr true))) sigma env cut)
+
+let abstract_one_arg = function
+    (loc,(id,None)) ->
+      (fun raw ->
+	 RLambda (dummy_loc,Name id, Explicit,
+		RHole (loc,Evd.BinderType (Name id)), raw))
+  | (loc,(id,Some typ)) ->
+      (fun raw ->
+	 RLambda (dummy_loc,Name id, Explicit, fst typ, raw))
+
+let rawconstr_of_fun args body =
+  List.fold_right abstract_one_arg args (fst body)
+
+let interp_fun sigma env args body =
+  let constr=understand sigma env (rawconstr_of_fun args body) in
+    match_args destLambda [] constr args
+
+let rec interp_bare_proof_instr info (sigma:Evd.evar_map) (env:Environ.env) = function
+    Pthus i -> Pthus (interp_bare_proof_instr info sigma env i)
+  | Pthen i -> Pthen (interp_bare_proof_instr info sigma env i)
+  | Phence i -> Phence (interp_bare_proof_instr info sigma env i)
+  | Pcut c -> Pcut (interp_cut
+		      (interp_no_bind (interp_statement
+					 (interp_constr_or_thesis true)))
+		      sigma env c)
+  | Psuffices c ->
+      Psuffices (interp_cut interp_suffices_clause sigma env c)
+  | Prew (s,c) -> Prew (s,interp_cut
+			  (interp_no_bind (interp_statement
+			     (interp_constr_in_type (get_eq_typ info env))))
+			  sigma env c)
+
+  | Psuppose hyps -> Psuppose (interp_hyps sigma env hyps)
+  | Pcase (params,pat,hyps) ->
+      let tparams,tpat,thyps = interp_cases info sigma env params pat hyps in
+	Pcase (tparams,tpat,thyps)
+  | Ptake witl ->
+      Ptake (List.map (fun c -> understand sigma env (fst c)) witl)
+  | Pconsider (c,hyps) -> Pconsider (interp_constr false sigma env c,
+				     interp_hyps sigma env hyps)
+  | Pper (et,c) -> Pper (et,interp_casee sigma env c)
+  | Pend bt -> Pend bt
+  | Pescape -> Pescape
+  | Passume hyps -> Passume (interp_hyps sigma env hyps)
+  | Pgiven hyps -> Pgiven (interp_hyps sigma env hyps)
+  | Plet hyps -> Plet (interp_hyps sigma env hyps)
+  | Pclaim st -> Pclaim (interp_statement (interp_constr true) sigma env st)
+  | Pfocus st -> Pfocus (interp_statement (interp_constr true) sigma env st)
+  | Pdefine (id,args,body) ->
+      let nargs,_,nbody = interp_fun sigma env args body in
+	Pdefine (id,nargs,nbody)
+  | Pcast (id,typ) ->
+      Pcast(id,interp_constr true sigma env typ)
+
+let rec interp_proof_instr info sigma env instr=
+  {emph = instr.emph;
+   instr = interp_bare_proof_instr info sigma env instr.instr}
+
+
+