type pos = int
type rgn = pos * pos
val null : rgn
type location = string * int * int
type map = Srcmap.map
val mk : unit -> map
val sync : map -> pos -> location -> unit
val nl : map -> pos -> unit
val last : map -> location
val location : map -> pos -> location
val dump : map -> unit
type point = map * pos
type region = map * rgn
module Str :
  sig val point : point -> string val region : region -> string end