sum package:streaming

Fold a Stream of numbers into their sum with the return value

mapped S.sum :: Stream (Stream (Of Int)) m r -> Stream (Of Int) m r

>>> S.sum $ each [1..10]
55 :> ()

>>> (n :> rest)  <- S.sum $ S.splitAt 3 $ each [1..10]

>>> System.IO.print n
6

>>> (m :> rest') <- S.sum $ S.splitAt 3 rest

>>> System.IO.print m
15

>>> S.print rest'
7
8
9
10

Lifted sum of functors.

Fold a Stream of numbers into their sum