mconcat is:exact

Fold a list using the monoid. For most types, the default definition for mconcat will be used, but the function is included in the class definition so that an optimized version can be provided for specific types.

>>> mconcat ["Hello", " ", "Haskell", "!"]
"Hello Haskell!"

Fold all values within a container using mappend and mempty

Fold streamed items into their monoidal sum

>>> S.mconcat $ S.take 2 $ S.map (Data.Monoid.Last . Just) S.stdinLn
first<Enter>
last<Enter>
Last {getLast = Just "last"} :> ()

Fold a stream of monoid elements by appending them.

mconcat = Stream.fold Fold.mconcat

Pre-release

Fold a list using the monoid. For most types, the default definition for mconcat will be used, but the function is included in the class definition so that an optimized version can be provided for specific types.

Monoid concat. Fold an input stream consisting of monoidal elements using mappend and mempty. Definition:

>>> mconcat = Fold.sconcat mempty

>>> monoids = fmap Data.Monoid.Sum $ Stream.enumerateFromTo 1 10

>>> Stream.fold Fold.mconcat monoids
Sum {getSum = 55}

Monoid concat. Scan an input stream consisting of monoidal elements using mappend and mempty. Definition:

>>> mconcat = Scanl.sconcat mempty

>>> monoids = fmap Data.Monoid.Sum $ Stream.enumerateFromTo 1 3

>>> Stream.toList $ Stream.scanl Scanl.mconcat monoids
[Sum {getSum = 0},Sum {getSum = 1},Sum {getSum = 3},Sum {getSum = 6}]

All arrays in the input must have equal shapes, including subarrays inside their elements.