Add First and Last wrappers around Maybe to Data.Monoid
|Reported by:||jyasskin||Owned by:|
|Type of failure:||None/Unknown||Test Case:|
|Related Tickets:||Differential Rev(s):|
First and Last
mappend to the first and last non-Nothing elements of the input. These instances seem to fit with the other simple instances in this file and are useful, for example, to turn foldMap into findFirst or findLast, or to get a really trivial Writer monad.