A natural transformation package.

Version on this page:0.3.1
LTS Haskell 13.3:0.4
Stackage Nightly 2019-01-19:0.4
Latest on Hackage:0.4

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BSD-3-Clause licensed by Andy Gill
Maintained by Andy Gill

Module documentation for 0.3.1

natural-transformation Hackage version Build Status

A natural transformation transforms a container f a into another container g a. Natural transformations act as functor morphisms in category theory. Technically, f and g should be functors, but we allow any correctly-shaped structure.



  • Rename Nat constructor to NT
  • Rename run to unwrapNT
  • Rename nat to wrapNT
  • Backport the Semigroup instance for (:~>) by conditionally depending on the semigroups package


  • Adding run and nat.


  • Adding Object
  • Rolled Control.Transformation into Control.Natural
  • Added RULES module
  • Required GHC 7.8 or greater
  • Semigroup instance for (:~>) on GHC 8.0 and up


  • Require GHC 7.6 or greater
  • Exposed ~> type synonym


  • Initial commit
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