kan-extensions

This package provides tools for working with various Kan extensions and Kan lifts in Haskell.

Among the interesting bits included are:

Right and left Kan extensions (Ran and Lan)
Right and left Kan lifts (Rift and Lift)
Multiple forms of the Yoneda lemma (Yoneda)
The Codensity monad, which can be used to improve the asymptotic complexity of code over free monads (Codensity, Density)
A "comonad to monad-transformer transformer" that is a special case of a right Kan lift. (CoT, Co)

Contact Information

Contributions and bug reports are welcome!

Please feel free to contact me through github or on the #haskell IRC channel on irc.freenode.net.

-Edward Kmett