Mercurial > urweb
annotate src/option_key_fn.sml @ 2253:d665925acff8
Factor out [Monoize.Fm] to make it accessible to [Sqlcache].
| author | Ziv Scully <ziv@mit.edu> |
|---|---|
| date | Mon, 21 Sep 2015 14:54:07 -0400 |
| parents | e4a7e3cd6f11 |
| children |
| rev | line source |
|---|---|
| ziv@2244 | 1 functor OptionKeyFn(K : ORD_KEY) |
| ziv@2244 | 2 : ORD_KEY where type ord_key = K.ord_key option = struct |
| ziv@2240 | 3 |
| ziv@2240 | 4 type ord_key = K.ord_key option |
| ziv@2240 | 5 |
| ziv@2240 | 6 val compare = |
| ziv@2240 | 7 fn (NONE, NONE) => EQUAL |
| ziv@2240 | 8 | (NONE, _) => LESS |
| ziv@2240 | 9 | (_, NONE) => GREATER |
| ziv@2240 | 10 | (SOME x, SOME y) => K.compare (x, y) |
| ziv@2240 | 11 |
| ziv@2240 | 12 end |