[Haskell-cafe] Maybe, maybe not.

[Edward Z. Yang]

Excerpts from michael rice's message of Tue Jan 26 21:34:42 -0500 2010:
> fromMaybe d x = case x of {Nothing -> d;Just v  -> v}
> fromMaybe z = maybe z id

They're equivalent.  Here the definition of maybe:

    maybe :: b -> (a -> b) -> Maybe a -> b
    maybe n _ Nothing  = n
    maybe _ f (Just x) = f x

Cheers,
Edward