namekey.sml

(*
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 * Copyright (c) 2007 Adobe Systems Inc., The Mozilla Foundation, Opera
 * Software ASA, and others.
 *)
structure NameKey = struct

type ord_key = Ast.NAME

fun cmpNS (Ast.OpaqueNamespace _, Ast.TransparentNamespace _) = LESS
  | cmpNS (Ast.TransparentNamespace _, Ast.OpaqueNamespace _) = GREATER
  | cmpNS (Ast.OpaqueNamespace i, Ast.OpaqueNamespace j) = Int.compare (i, j)
  | cmpNS (Ast.TransparentNamespace i, Ast.TransparentNamespace j) = Ustring.compare i j

(* FIXME: SML.NET doesn't implement List.collate *)
fun collate (cmp:('a * 'a -> order))
            ((ls1:'a list), (ls2:'a list))
    : order =
    (case (ls1, ls2) of
     ([], []) => EQUAL
       | ([], _) => LESS
       | (_, []) => GREATER
       | ((x::ls1'), (y::ls2')) =>
         (case (cmp (x, y)) of
          EQUAL => collate cmp (ls1', ls2')
            | ord => ord))

fun compare (a:ord_key, b:ord_key)
    : order =
    case Ustring.compare (#id a) (#id b) of
		LESS => LESS
      | GREATER => GREATER
      | EQUAL => cmpNS ((#ns a), (#ns b))
				 
end