Added (in the attic) a patch that modifies Grammar to use Fix.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/menhir@334 0f8b5475-4b4e-0410-85a8-ee3154a6bfe7

attic/fix.patch

+Index: grammar.ml
+===================================================================
+--- grammar.ml	(revision 128)
++++ grammar.ml	(working copy)
+@@ -273,6 +273,15 @@
+       )
+     )
+ 
++  type property =
++      t
++
++  let bottom =
++    empty
++
++  let is_maximal _ =
++    false
++
+ end
+ 
+ (* Maps over terminals. *)
+@@ -787,18 +796,60 @@
+   );
+   property, symbol_has_property
+ 
+-let () =
++let nonempty =
+   let nonempty, _ = compute true in
+   for nt = Nonterminal.start to Nonterminal.n - 1 do
+     if not nonempty.(nt) then
+       Error.warningN
+ 	(Nonterminal.positions nt)
+ 	(Printf.sprintf "%s generates the empty language." (Nonterminal.print false nt))
+-  done
++  done;
++  nonempty
+ 
+ let (nullable : bool array), (nullable_symbol : Symbol.t -> bool) =
+   compute false
+ 
++let rhs basecase nt get =
++  (* disjunction over all productions for this nonterminal *)
++  Production.foldnt nt false (fun prod accu ->
++    accu ||
++    let rhs = Production.rhs prod in
++    (* conjunction over all symbols in the right-hand side *)
++    Array.fold_left (fun accu symbol ->
++      accu && match symbol with
++      | Symbol.T _ ->
++	  basecase
++      | Symbol.N nt ->
++	  get nt
++    ) true rhs
++  )
++
++module NONEMPTY =
++  Fix.Make
++    (Maps.PersistentMapsToImperativeMaps(NonterminalMap))
++    (Boolean)
++    (struct
++      type variable = Nonterminal.t
++      type property = bool
++      let rhs = rhs true
++    end)
++
++module NULLABLE =
++  Fix.Make
++    (Maps.PersistentMapsToImperativeMaps(NonterminalMap))
++    (Boolean)
++    (struct
++      type variable = Nonterminal.t
++      type property = bool
++      let rhs = rhs false
++    end)
++
++let () =
++  for nt = Nonterminal.start to Nonterminal.n - 1 do
++    assert (nonempty.(nt) = NONEMPTY.get nt);
++    assert (nullable.(nt) = NULLABLE.get nt)
++  done
++
+ (* ------------------------------------------------------------------------ *)
+ (* Compute FIRST sets. *)
+ 
+@@ -840,6 +891,54 @@
+     TerminalSet.compare original updated <> 0
+   )
+ 
++module FIRST =
++  Fix.Make
++    (Maps.PersistentMapsToImperativeMaps(NonterminalMap))
++    (TerminalSet)
++    (struct
++      type variable = Nonterminal.t
++      type property = TerminalSet.t
++
++      let rhs nt first =
++
++	let first_symbol = function
++	  | Symbol.T tok ->
++	      TerminalSet.singleton tok
++	  | Symbol.N nt ->
++	      first nt
++	in
++
++	let nullable_first_rhs (rhs : Symbol.t array) (i : int) : bool * TerminalSet.t =
++	  let length = Array.length rhs in
++	  assert (i <= length);
++	  let rec loop i toks =
++	    if i = length then
++	      true, toks
++	    else
++	      let symbol = rhs.(i) in
++	      let toks = TerminalSet.union (first_symbol symbol) toks in
++	      if nullable_symbol symbol then
++		loop (i+1) toks
++	      else
++		false, toks
++	  in
++	  loop i TerminalSet.empty
++	in
++
++	(* union over all productions for this nonterminal *)
++	Production.foldnt nt TerminalSet.empty (fun prod accu ->
++	  let rhs = Production.rhs prod in
++	  let _, toks = nullable_first_rhs rhs 0 in
++	  TerminalSet.union toks accu
++        )
++
++    end)
++
++let () =
++  for nt = Nonterminal.start to Nonterminal.n - 1 do
++    assert (TerminalSet.equal first.(nt) (FIRST.get nt))
++  done
++
+ (* ------------------------------------------------------------------------ *)
+ (* Dump the analysis results. *)
+