New Algorithms - A Functional Perspective

All new functions have a pendant in the purely functional language Haskell.

Functions	Haskell
std::for_each_n	map
std::exclusive_scan	scanl
std::inclusive_scan	scanl1
std::transform_exclusive_scan and std::transform_inclusive_scan	composition of map and scanl or scanl1
std::reduce	foldl or foldl1
transform_reduce	composition of map and foldl or foldl1

Before I show you Haskell in action, let me briefly discuss the different functions.

Functions	Description
map	applies a function to a list
foldl and foldl1	apply a binary operation to a list and reduce the list to a value. foldl needs, in contrast to foldl1, an initial value.
scanl and scanl1	apply the same strategy as foldl and foldl1 but produce all intermediate results so that you will get back a list

• Note: foldl, foldl1, scanl, and scanl1 start their job from the left.

Let’s have a look at the running example of Haskell functions​: