Affinement encore

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@3316 85f007b7-540e-0410-9357-904b9bb8a0f7

2 files changed, 22 insertions, 3 deletions

diff --git a/parsing/egrammar.ml b/parsing/egrammar.ml
index 84b1aa0f0..a7cfcc591 100644
--- a/parsing/egrammar.ml
+++ b/parsing/egrammar.ml
@@ -50,6 +50,10 @@ let constr_level assoc = function
   | 8 -> assert (assoc <> Some Gramext.LeftA); "top"
   | n -> (string_of_int n)^(assoc_level (canonise_assoc assoc))
 
+let constr_prod_level = function
+  | 8 -> "top"
+  | n -> string_of_int n
+
 let numeric_levels =
   ref [8,Some Gramext.RightA; 1,Some Gramext.RightA; 0,Some Gramext.RightA]
 
@@ -67,7 +71,7 @@ let eq_assoc a b = match (canonise_assoc a, canonise_assoc b) with
 let find_position assoc = function
   | None -> None, Some (canonise_assoc assoc)
   | Some n ->
-      if n = 8 & assoc = Some Gramext.LeftA then 
+      if n = 8 & canonise_assoc assoc = Gramext.LeftA then 
 	error "Left associativity not allowed at level 8";
       let after = ref (8,Some Gramext.RightA) in
       let rec add_level q = function
@@ -176,7 +180,7 @@ let rec build_prod_item univ assoc = function
       match get_constr_production_entry assoc typ with
 	| (eobj,None) -> Gramext.Snterm (Gram.Entry.obj eobj)
 	| (eobj,Some lev) -> 
-	    Gramext.Snterml (Gram.Entry.obj eobj,constr_level assoc lev)
+	    Gramext.Snterml (Gram.Entry.obj eobj,constr_prod_level lev)
 
 let symbol_of_prod_item univ assoc = function
   | Term tok -> (Gramext.Stoken tok, None)
diff --git a/parsing/extend.ml b/parsing/extend.ml
index 04a31fa49..ae3561c1f 100644
--- a/parsing/extend.ml
+++ b/parsing/extend.ml
@@ -234,10 +234,25 @@ let gram_rule univ (name,pil,act) =
   let a = to_act_check_vars act_env act in
   { gr_name = name; gr_production = pilc; gr_action = a }
 
+let border = function
+  | NonTerm (ProdPrimitive (ETConstr(_,BorderProd (_,a))),_) :: _ -> a
+  | _ -> None
+
+let clever_assoc = function
+  | [g] when g.gr_production <> [] ->
+      (match border g.gr_production, border (List.rev g.gr_production) with
+	  Some RightA, Some LeftA -> Some NonA
+	| a, b when a=b -> a
+	| Some LeftA, Some RightA -> Some LeftA (* since LR *)
+	| _ -> None)
+  | _ -> None
+
 let gram_entry univ (nt, ass, rl) =
+  let l = List.map (gram_rule (univ,nt)) rl in
+  let ass = if ass = None then clever_assoc l else ass in
   { ge_name = nt;
     gl_assoc = ass;
-    gl_rules = List.map (gram_rule (univ,nt)) rl }
+    gl_rules = l }
 
 let interp_grammar_command univ ge entryl =
   { gc_univ = univ;