(* var.sml
 *
 * COPYRIGHT (c) 2010 The Diderot Project (http://diderot.cs.uchicago.edu)
 * All rights reserved.
 *)

structure Var =
  struct

    datatype var = datatype AST.var

    datatype var_kind = datatype AST.var_kind

    fun nameOf (V{name, ...}) = name
    fun typeOf (V{ty, ...}) = ty
    fun monoTypeOf (V{ty=([], ty), ...}) = ty
      | monoTypeOf (V{name, ...}) = raise Fail(name ^ " is not monomrphic")
    fun kindOf (V{kind, ...}) = kind

    fun new (name, kind, ty) = let
	  val id = Stamp.new()
	  in
	    V{name=Atom.toString name, id=id, kind=kind, ty=([], ty)}
	  end

    fun newPoly (name, kind, scheme) = let
	  val id = Stamp.new()
	  in
	    V{name=Atom.toString name, id=id, kind=kind, ty=scheme}
	  end

    fun compare (V{id=a, ...}, V{id=b, ...}) = Stamp.compare(a, b)
    fun same (V{id=a, ...}, V{id=b, ...}) = Stamp.same(a, b)
    fun hash (V{id, ...}) = Stamp.hash id

    local
      structure V =
	struct
	  type ord_key = var
	  val compare = compare
	end
    in
    structure Map = RedBlackMapFn (V)
    structure Set = RedBlackSetFn (V)
    end

  end