Index - O
| odd | Prelude.Compat |
| onException | Control.Exception.Compat |
| optional | Control.Applicative.Compat |
| or | Data.Foldable.Compat, Prelude.Compat |
| Ord | Prelude.Compat |
| Ordering | Prelude.Compat |
| otherwise | Data.Bool.Compat, Prelude.Compat |
| Overflow | Control.Exception.Compat |