| 1 | (* Copyright (C) 2004-2007 Henry Cejtin, Matthew Fluet, Suresh |
| 2 | * Jagannathan, and Stephen Weeks. |
| 3 | * |
| 4 | * MLton is released under a BSD-style license. |
| 5 | * See the file MLton-LICENSE for details. |
| 6 | *) |
| 7 | |
| 8 | functor Scale (S: SCALE_STRUCTS): SCALE = |
| 9 | struct |
| 10 | |
| 11 | open S |
| 12 | |
| 13 | datatype t = One | Two | Four | Eight |
| 14 | |
| 15 | val toString = |
| 16 | fn One => "1" |
| 17 | | Two => "2" |
| 18 | | Four => "4" |
| 19 | | Eight => "8" |
| 20 | |
| 21 | val layout = Layout.str o toString |
| 22 | |
| 23 | val fromInt: int -> t option = |
| 24 | fn 1 => SOME One |
| 25 | | 2 => SOME Two |
| 26 | | 4 => SOME Four |
| 27 | | 8 => SOME Eight |
| 28 | | _ => NONE |
| 29 | |
| 30 | val fromBytes: Bytes.t -> t option = |
| 31 | fromInt o Bytes.toInt |
| 32 | |
| 33 | val toInt: t -> int = |
| 34 | fn One => 1 |
| 35 | | Two => 2 |
| 36 | | Four => 4 |
| 37 | | Eight => 8 |
| 38 | |
| 39 | end |