HUGE COMMIT

1. when applying a functor F(X) := B to a module M, the obtained module
   is no longer B{X.t := M.t for all t}, but B{X.t := b where b is the
   body of t in M}. In principle it is now easy to fine tune the behaviour
   to choose whether b or M.t must be used. This change implies modifications
   both inside and outside the kernel.
2. for each object in the library it is now necessary to define the behaviour
   w.r.t. the substitution {X.t := b}. Notice that in many many cases the
   pre-existing behaviour w.r.t. the substitution {X.t := M.t} was broken
   (in the sense that it used to break several invariants). This commit
   fixes the behaviours for most of the objects, excluded
     a) coercions: a future commit should allow any term to be declared
        as a coercion; moreover the invariant that just a coercion path
        exists between two classes will be broken by the instantiation.
     b) global references when used as arguments of a few tactics/commands
   In all the other cases the behaviour implemented is the one that looks
   to me as the one expected by the user (if possible):
   [ terminology: not expanded (X.t := M.t) vs expanded (X.t := b) ]
     a) argument scopes: not expanded
     b) SYNTAXCONSTANT: expanded
     c) implicit arguments: not expanded
     d) coercions: expansion to be done (for now not expanded)
     e) concrete syntax tree for patterns: expanded
     f) concrete syntax tree for raw terms: expanded
     g) evaluable references (used by unfold, delta expansion, etc.): not
        expanded
     h) auto's hints: expanded when possible (i.e. when the expansion of the
        head of the pattern is rigid)
     i) realizers (for program extraction): nothing is done since the actual
        code does not look for the realizer of definitions with a body;
        however this solution is fragile.
     l) syntax and notation: expanded
     m) structures and canonical structures: an invariant says that no
        parameter can happear in them ==> the substitution always yelds the
        original term
     n) stuff related to V7 syntax: since this part of the code is doomed
        to disappear, I have made no effort to fix a reasonable semantics;
        not expanded is the default one applied
     o) RefArgTypes: to be understood. For now a warning is issued whether
        expanded != not expanded, and the not expanded solution is chosen.


git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@6555 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 114 insertions, 0 deletions

diff --git a/pretyping/detyping.ml b/pretyping/detyping.ml
index 6a0ea00602..880605313a 100644
--- a/pretyping/detyping.ml
+++ b/pretyping/detyping.ml
@@ -492,3 +492,117 @@ and detype_binder tenv bk avoid env na ty c =
     | BProd -> RProd (dummy_loc, na',detype tenv [] env ty, r)
     | BLambda -> RLambda (dummy_loc, na',detype tenv [] env ty, r)
     | BLetIn -> RLetIn (dummy_loc, na',detype tenv [] env ty, r)
+
+let rec subst_pat subst pat = 
+  match pat with
+  | PatVar _ -> pat
+  | PatCstr (loc,((kn,i),j),cpl,n) -> 
+      let kn' = subst_kn subst kn 
+      and cpl' = list_smartmap (subst_pat subst) cpl in
+	if kn' == kn && cpl' == cpl then pat else
+	  PatCstr (loc,((kn',i),j),cpl',n)
+
+let rec subst_raw subst raw = 
+  match raw with
+  | RRef (loc,ref) -> 
+      let ref',t = subst_global subst ref in 
+	if ref' == ref then raw else
+         detype (false,Global.env ()) [] [] t
+
+  | RVar _ -> raw
+  | REvar _ -> raw
+  | RPatVar _ -> raw
+
+  | RApp (loc,r,rl) -> 
+      let r' = subst_raw subst r 
+      and rl' = list_smartmap (subst_raw subst) rl in
+	if r' == r && rl' == rl then raw else
+	  RApp(loc,r',rl')
+
+  | RLambda (loc,n,r1,r2) -> 
+      let r1' = subst_raw subst r1 and r2' = subst_raw subst r2 in
+	if r1' == r1 && r2' == r2 then raw else
+	  RLambda (loc,n,r1',r2')
+
+  | RProd (loc,n,r1,r2) -> 
+      let r1' = subst_raw subst r1 and r2' = subst_raw subst r2 in
+	if r1' == r1 && r2' == r2 then raw else
+	  RProd (loc,n,r1',r2')
+
+  | RLetIn (loc,n,r1,r2) -> 
+      let r1' = subst_raw subst r1 and r2' = subst_raw subst r2 in
+	if r1' == r1 && r2' == r2 then raw else
+	  RLetIn (loc,n,r1',r2')
+
+  | RCases (loc,(ro,rtno),rl,branches) -> 
+      let ro' = option_smartmap (subst_raw subst) ro 
+      and rtno' = ref (option_smartmap (subst_raw subst) !rtno)
+      and rl' = list_smartmap (fun (a,x as y) ->
+        let a' = subst_raw subst a in
+        let (n,topt) = !x in 
+        let topt' = option_smartmap
+          (fun (loc,(sp,i),x as t) ->
+            let sp' = subst_kn subst sp in
+            if sp == sp' then t else (loc,(sp',i),x)) topt in
+        if a == a' && topt == topt' then y else (a',ref (n,topt'))) rl
+      and branches' = list_smartmap 
+			(fun (loc,idl,cpl,r as branch) ->
+			   let cpl' = list_smartmap (subst_pat subst) cpl
+			   and r' = subst_raw subst r in
+			     if cpl' == cpl && r' == r then branch else
+			       (loc,idl,cpl',r'))
+			branches
+      in
+	if ro' == ro && rl' == rl && branches' == branches then raw else
+	  RCases (loc,(ro',rtno'),rl',branches')
+
+  | ROrderedCase (loc,b,ro,r,ra,x) -> 
+      let ro' = option_smartmap (subst_raw subst) ro
+      and r' = subst_raw subst r 
+      and ra' = array_smartmap (subst_raw subst) ra in
+	if ro' == ro && r' == r && ra' == ra then raw else
+	  ROrderedCase (loc,b,ro',r',ra',x)
+
+  | RLetTuple (loc,nal,(na,po),b,c) ->
+      let po' = option_smartmap (subst_raw subst) po
+      and b' = subst_raw subst b 
+      and c' = subst_raw subst c in
+	if po' == po && b' == b && c' == c then raw else
+          RLetTuple (loc,nal,(na,po'),b',c')
+      
+  | RIf (loc,c,(na,po),b1,b2) ->
+      let po' = option_smartmap (subst_raw subst) po
+      and b1' = subst_raw subst b1 
+      and b2' = subst_raw subst b2 
+      and c' = subst_raw subst c in
+	if c' == c & po' == po && b1' == b1 && b2' == b2 then raw else
+          RIf (loc,c',(na,po'),b1',b2')
+
+  | RRec (loc,fix,ida,bl,ra1,ra2) -> 
+      let ra1' = array_smartmap (subst_raw subst) ra1
+      and ra2' = array_smartmap (subst_raw subst) ra2 in
+      let bl' = array_smartmap
+        (list_smartmap (fun (na,obd,ty as dcl) ->
+          let ty' = subst_raw subst ty in
+          let obd' = option_smartmap (subst_raw subst) obd in
+          if ty'==ty & obd'==obd then dcl else (na,obd',ty')))
+        bl in
+	if ra1' == ra1 && ra2' == ra2 && bl'==bl then raw else
+	  RRec (loc,fix,ida,bl',ra1',ra2')
+
+  | RSort _ -> raw
+
+  | RHole (loc,ImplicitArg (ref,i)) ->
+      let ref',_ = subst_global subst ref in 
+	if ref' == ref then raw else
+	  RHole (loc,InternalHole)
+  | RHole (loc, (BinderType _ | QuestionMark | CasesType |
+      InternalHole | TomatchTypeParameter _)) -> raw
+
+  | RCast (loc,r1,r2) -> 
+      let r1' = subst_raw subst r1 and r2' = subst_raw subst r2 in
+	if r1' == r1 && r2' == r2 then raw else
+	  RCast (loc,r1',r2')
+
+  | RDynamic _ -> raw
+