foldl

Composable, streaming, and efficient left folds

Version on this page:	1.2.1
LTS Haskell 24.27:	1.4.18@rev:1
Stackage Nightly 2026-01-10:	1.4.18@rev:2
Latest on Hackage:	1.4.18@rev:2

See all snapshots foldl appears in

BSD-3-Clause licensed by Gabriel Gonzalez

Maintained by [email protected]

This version can be pinned in stack with:foldl-1.2.1@sha256:7638fddf8ff08bf2098471e1af317e23ee9544140eeae3180c2087006ac2a2d7,1500

Module documentation for 1.2.1

Control
- Control.Foldl
  - Control.Foldl.ByteString
  - Control.Foldl.Text

Depends on 11 packages(full list with versions):

base, bytestring, comonad, containers, contravariant, mwc-random, primitive, profunctors, text, transformers, vector

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.