(* Title: Pure/General/buffer.ML
ID: $Id$
Author: Markus Wenzel, TU Muenchen
Simple string buffers.
*)
signature BUFFER =
sig
type T
val empty: T
val add: string -> T -> T
val content: T -> string
val write: Path.T -> T -> unit
val write_nonempty: Path.T -> T -> unit
end;
structure Buffer: BUFFER =
struct
datatype T = Buffer of string list;
val empty = Buffer [];
fun add x (Buffer xs) = Buffer (x :: xs);
fun content (Buffer xs) = implode (rev xs);
fun write path buffer = File.write path (content buffer);
fun write_nonempty _ (Buffer []) = ()
| write_nonempty path buffer = write path buffer;
end;