https://github.com/klntsky/purescript-balanced-fold

Folds a list of values, trying as much as possible to balance.
https://github.com/klntsky/purescript-balanced-fold

Last synced: 5 days ago
JSON representation

Folds a list of values, trying as much as possible to balance.

• Host: GitHub
• URL: https://github.com/klntsky/purescript-balanced-fold
• Owner: klntsky
• Created: 2019-03-31T12:26:25.000Z (almost 6 years ago)
• Default Branch: master
• Last Pushed: 2019-05-24T15:50:13.000Z (over 5 years ago)
• Last Synced: 2024-11-09T15:47:42.567Z (2 months ago)
• Language: PureScript
• Size: 5.86 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
# purescript-balanced-fold [![Dependencies](https://img.shields.io/librariesio/github/klntsky/purescript-balanced-fold.svg)](https://libraries.io/github/klntsky/purescript-balanced-fold) [![Build status](https://travis-ci.org/klntsky/purescript-balanced-fold.svg?branch=master)](https://travis-ci.org/klntsky/purescript-balanced-fold)

A balanced fold, also called tree fold, is an operation of folding a list of values using some associative operation, trying as much as possible to balance.

Can be useful for constructing balanced binary trees, or more stable summation.

# Example

Given a binary tree,

```purescript

data T a = Empty | L a | B (T a) (T a)

infixl 6 B as :*:

```

which is an instance of `Semigroup` with `append = B` and `Monoid` with `mempty = Empty`,

```purescript

balancedFold (map L (1..5)) ≡ ((L 1) :*: (((L 2) :*: (L 3)) :*: ((L 4) :*: (L 5))))

```

Check out [the tests](test/TestMain.purs) for more examples.

# See also:

1. [treefold](http://hackage.haskell.org/package/treefold) on Hackage.

# Module documentation

Browse [generated-docs](generated-docs/Data/BalancedFold.md).

PM me if you want this library to be on Pursuit.