rename Hashweak.add to Hashweak.set to stress its one-time semantic

src/core/trans.ml

@@ -54,7 +54,7 @@ let fold fn v =
   let h = WHtask.create 63 in
   let rewind acc task =
     let acc = fn task acc in
-    WHtask.add h task acc;
+    WHtask.set h task acc;
     acc
   in
   let current task =

src/util/hashweak.ml

@@ -38,12 +38,12 @@ module Make (S : Util.Tagged) = struct
   let mem_tag  h = Hashtbl.mem  h.table
   let find_tag h = Hashtbl.find h.table
 
-  let add_tag h t e v =
+  let set_tag h t e v =
     assert (not (mem_tag h t));
     Gc.finalise h.final e;
     add_tag h t v
 
-  let add  h e = add_tag  h (S.tag e) e
+  let set  h e = set_tag  h (S.tag e) e
   let mem  h e = mem_tag  h (S.tag e)
   let find h e = find_tag h (S.tag e)
 
@@ -53,7 +53,7 @@ module Make (S : Util.Tagged) = struct
       try find_tag h t
       with Not_found ->
         let v = fn e in
-        add_tag h t e v;
+        set_tag h t e v;
         v
 
   let memoize_option n fn =

src/util/hashweak.mli

@@ -31,8 +31,8 @@ module Make (S : Util.Tagged) : sig
   val mem : 'a t -> S.t -> bool
     (* test if a key is bound *)
 
-  val add : 'a t -> S.t -> 'a -> unit
-    (* bind the key with the value given *)
+  val set : 'a t -> S.t -> 'a -> unit
+    (* bind the key _once_ with the given value *)
 
   val memoize : int -> (S.t -> 'a) -> (S.t -> 'a)
     (* create a memoizing function *)