(*  Title:      Pure/ML-Systems/polyml_old_basis.ML

    ID:         $Id$

Fixes for the old SML basis library (before Poly/ML 4.2.0).

*)

structure String =

struct

  fun isSuffix s1 s2 =

    let val n1 = size s1 and n2 = size s2

    in if n1 = n2 then s1 = s2 else n1 <= n2 andalso String.substring (s2, n2 - n1, n1) = s1 end;

  fun isSubstring s1 s2 =

    String.isPrefix s1 s2 orelse

      size s1 < size s2 andalso isSubstring s1 (String.extract (s2, 1, NONE)); 

  open String;

end;

structure Substring =

struct

  open Substring;

  val full = all;

end;

structure Posix =

struct

  open Posix;

  structure IO =

  struct

    open IO;

    val mkTextReader = mkReader;

    val mkTextWriter = mkWriter;

  end;

end;

structure TextIO =

struct

  open TextIO;

  fun inputLine is =

    let val s = TextIO.inputLine is

    in if s = "" then NONE else SOME s end;

end;