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

structure Types =
  struct

    datatype kind
      = ScalarKind
      | TypeKind

    and ty
      = TyVar of ty_var
      | TyBool
      | TyInt
      | TyReal
      | TyString
      | TyKernel of {diff : dim}
      | TyField of {diff : dim, order : dim list, dim : dim}
      | TyTensor of {order : dim list}
      | TyImage of {order : dim list, dim : dim}
      | TyArray of ty * dim list

    and dim
      = DimConst of int			(* i *)
      | DimExp of (dim * int)		(* d + i *)
      | DimVar of dim_var

    fun dimToString (DimConst of n) = Int.toString n
      | dimToString (DimExp(d, n)) =
	  if (n < 0)
	    then concat[dimToString d, "-", Int.toString(~n)]
	    else concat[dimToString d, "+", Int.toString n]
      | dimToString (DimVar dv) = ??

    fun toString ty = (case ty
	   of TyVar tv => ??
	    | TyBool => "bool"
	    | TyInt => "int"
	    | TyReal => "real"
	    | TyString => "string"
	    | TyKernel{diff} => "kernel#" ^ dimToString diff
	    | TyField{diff, order, dim} =>
	    | TyTensor{order, dim} =>
	    | TyArray(ty, dim) =>
	  (* end case *))

  end