Index - O
| odd | BasePrelude |
| on | BasePrelude |
| onException | BasePrelude |
| optional | BasePrelude |
| or | BasePrelude |
| Ord | BasePrelude |
| Ordering | BasePrelude |
| orElse | BasePrelude |
| OtherError | BasePrelude |
| otherwise | BasePrelude |
| Overflow | BasePrelude |
base-prelude-0.1.0: The most complete prelude formed from only the "base" package