A handy generalized filter
For quite a while, I’ve been using a handy operation for filtering functional events:
justE :: Event (Maybe a) -> Event a
The idea of justE
is to drop the Nothing
-valued occurrences and strip off the Just
constructors from the remaining occurrences. Recently I finally noticed the similarity with a standard function (in Data.Maybe
):
catMaybes :: [Maybe a] -> [a]