exists

Existential datatypes holding evidence of constraints

http://github.com/glehel/exists

Latest on Hackage:0.2

This package is not currently in any snapshots. If you're interested in using it, we recommend adding it to Stackage Nightly. Doing so will make builds more reliable, and allow stackage.org to host generated Haddocks.

BSD-3-Clause licensed by Gábor Lehel
Maintained by Gábor Lehel

This package contains:

  • Existential datatypes for holding evidence of constraints on types of kind * and * -> *;

  • Type classes for existential datatypes holding evidence of constraints on types of kind * and * -> *;

  • Completely useless existential datatypes holding evidence of no constraint on types of kind * and * -> *;

  • Assorted type class instances for the above;

  • A type-level combinator for combining constraint constructors.

(Some of these might be better off as separate packages.)

Data.Exists has most of the important things.

Minimum GHC: 7.4

Changes in 0.2:

  • Removed Comonad-related things (they were probably useless anyways)

  • Added Data.Exists.CPS