#lang sml
(*
 * (c) Andreas Rossberg 1999-2007
 *
 * Helpers for handling source strings
 *)

signature SOURCE =
sig
    type source = string
    type pos    = {abs : int, lin : int, col : int}
    type region = {left : pos, right : pos}
    type info   = {file : string option, region : region}

    exception Error of (int * int) * string

    val nowherePos : pos
    val nowhere :  info
    val over :     info * info -> info
    val between :  info * info -> info
    val compare :  info * info -> order
end