open-witness

open witnesses

https://github.com/AshleyYakeley/open-witness

Version on this page:0.6
LTS Haskell 24.24:0.7
Stackage Nightly 2025-12-17:0.7
Latest on Hackage:0.7

See all snapshots open-witness appears in

BSD-2-Clause licensed by Ashley Yakeley
Maintained by <[email protected]>
This version can be pinned in stack with:open-witness-0.6@sha256:80d4ddbdf3acbe98b1a867388efe1478d73f5caf9a34e5bfbb8e0409c299e2da,2998

Module documentation for 0.6

  • Data
    • Data.Type
      • Data.Type.OpenWitness
        • Data.Type.OpenWitness.Dynamic
        • Data.Type.OpenWitness.Exception
        • Data.Type.OpenWitness.Instance
        • Data.Type.OpenWitness.ST
        • Data.Type.OpenWitness.TypeRep
        • Data.Type.OpenWitness.Typeable
        • Data.Type.OpenWitness.Witnessed

Open witnesses are witnesses that can witness to any type. However, they cannot be constructed, they can only be generated in the IO monad. See the 2008 draft paper Witnesses and Open Witnesses (https://semantic.org/wp-content/uploads/Open-Witnesses.pdf).

Changes

[0.6] - 2022-05-10

  • update for witness-0.6
  • move module hierarchy
  • Witnessed now synonym for PairType IOWitness

[0.5] - 2020-09-22