basis-library/general/bool.sml

   1 (* Copyright (C) 1999-2006, 2008 Henry Cejtin, Matthew Fluet, Suresh
   2  *    Jagannathan, and Stephen Weeks.
   3  * Copyright (C) 1997-2000 NEC Research Institute.
   4  *
   5  * MLton is released under a BSD-style license.
   6  * See the file MLton-LICENSE for details.
   7  *)
   8
   9 structure Bool: BOOL =
  10    struct
  11       datatype bool = datatype bool
  12
  13       val not = not
  14
  15       fun scan reader state =
  16          case reader state of
  17             NONE => NONE
  18           | SOME(c, state) =>
  19                case c of
  20                   #"f" => (case Reader.reader4 reader state of
  21                               SOME((#"a", #"l", #"s", #"e"), state) =>
  22                                  SOME(false, state)
  23                             | _ => NONE)
  24                 | #"t" => (case Reader.reader3 reader state of
  25                               SOME((#"r", #"u", #"e"), state) =>
  26                                  SOME(true, state)
  27                             | _ => NONE)
  28                 | _ => NONE
  29
  30       val fromString = StringCvt.scanString scan
  31
  32       val toString =
  33          fn true => "true"
  34           | false => "false"
  35    end
  36
  37 structure BoolGlobal: BOOL_GLOBAL = Bool
  38 open BoolGlobal