free-category: Free category

[ algebra, category, category-theory, control, library, monads, mpl ] [ Propose Tags ]

Free categories

[Skip to Readme]


Maintainer's Corner

For package maintainers and hackage trustees


Versions [RSS],,,,,, (info)
Change log
Dependencies base (>=4.9 && <5), free-algebras (>= [details]
License MPL-2.0
Copyright (c) 2018-2019 Marcin Szamotulski
Author Marcin Szamotulski
Category Algebra, Control, Monads, Category
Home page
Bug tracker
Source repo head: git clone
Uploaded by coot at 2019-12-05T13:21:13Z
Distributions NixOS:
Downloads 2188 total (3 in the last 30 days)
Rating (no votes yet) [estimated by Bayesian average]
Your Rating
  • λ
  • λ
  • λ
Status Docs available [build log]
Last success reported on 2019-12-05 [all 1 reports]

Readme for free-category-

[back to package description]

Free Category

Maintainer: coot CircleCI

This package contains efficient implementations of free categories. There are various representations available:

  • real-time queues (C. Okasaki 'Pure Functional Data Structures')
  • type aligned lists
  • continuation passing style (Church encoding)

Free arrows and free Kleisli categories are also included.

Free categories are useful to model state machines in a simple yet type safe manner. For that purpose Kleisli categories are a very useful target which allows to include monadic computations. This package contains a useful generalisation of Kliesli categories captured by EffectCategory class (categories with effects), and a (free) transformer which lifts a category to a category with effects.


Check performance characteristics of various representations: