squares-0.1: The double category of Hask functors and profunctors
Data.Foldable.Square
Description
foldMap :: (Foldable f, Monoid m, IsFList gs) => Square '[Forget m] '[Forget m] '[f] gs Source #
+--f--+ | v | !m-@-!m | ? | +--?--+
foldMap as a square. Note that because Forget ignores its output parameter, this square can have any list of functors as output type.
foldMap
Forget