Universum.Monoid

This module reexports functions to work with monoids plus adds extra useful functions.

Documentation

module Data.Monoid

module Data.Semigroup

maybeToMonoid :: Monoid m => Maybe m -> m

Extracts Monoid value from Maybe returning mempty if Nothing.

>>> maybeToMonoid (Just [1,2,3] :: Maybe [Int])
[1,2,3]
>>> maybeToMonoid (Nothing :: Maybe [Int])
[]