foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a list, reduces the list using the binary operator, from left to right:
> foldl f z [x1, x2, ..., xn] == (...((z `f` x1) `f` x2) `f`...) `f` xn
The list must be finite.

This library provides strict left folds that stream in constant memory, and you can combine folds using Applicative style to derive new folds. Derived folds still traverse the container just once and are often as efficient as hand-written folds.
Version 1.0.0

foldl1 is a variant of foldl that has no starting value argument, and thus must be applied to non-empty lists.

A strict version of foldl.

Fold over the elements of a structure, associating to the left, but strictly.

A strict version of foldl1

Monadic fold over the elements of a structure, associating to the left, i.e. from left to right.

Consume the chunks of a lazy Text with a strict, tail-recursive, accumulating left fold.

g**foldl** :: Data a => (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> a -> c a

g**foldl**Accum :: Data d => (forall e r. Data e => a -> c (e -> r) -> e -> (a, c r)) -> (forall g. a -> g -> (a, c g)) -> a -> d -> (a, c d)

gfoldl with accumulation