Data.Maybe.Extra

Extra functions for dealing with Maybe.

Documentation

whenMaybe :: Monad m => Bool -> m a -> m (Maybe a)

When the predicate is true, return maybe the action's return value.

whenJust :: Monad m => Maybe a -> (a -> m c) -> m ()

When a value is Just, do something with it, monadically.

sole :: [a] -> Maybe a

Return the sole element of the list or nothing.