[Haskell-beginners] Bool -> a -> Maybe a, or something similar

|Hello! I tried Hoogle, but it didn't seem to have what I was after. I'm looking for something like this:

maybeWhen :: Bool -> a -> Maybe a maybeWhen cond = if cond then Just else const Nothing

Is there a builtin that has the above sort of behaviour? I suppose it can even be generalised:

maybeWhen :: (MonadPlus m) => Bool -> a -> m a maybeWhen cond = if cond then return else const mzero

Tacit |