dec

Decidable propositions.

https://github.com/phadej/dec

LTS Haskell 24.39:0.0.6@rev:1
Stackage Nightly 2026-05-11:0.0.6@rev:2
Latest on Hackage:0.0.6@rev:2

See all snapshots dec appears in

BSD-3-Clause licensed by Oleg Grenrus
Maintained by Oleg.Grenrus
This version can be pinned in stack with:dec-0.0.6@sha256:bad2c5f159ee81d2c2fd11e7957d76c4f37f3a40c9866f76014b131575aa35fe,1399

Module documentation for 0.0.6

Depends on 2 packages(full list with versions):
base, boring
Used by 1 package in nightly-2026-05-11(full list with versions):
singleton-bool

This package provides a Dec type.

type Neg a = a -> Void

data Dec a
    = Yes a
    | No (Neg a)

Changes

Revision history for dec

0.0.6

  • Support GHC-8.6.5…9.10.1

0.0.5

  • Add boringYes and absurdNo.
  • Add Decidable a => Boring (Dec a) instance.
  • Add Decidable (), Decidable Void, Decidable (a, b) instances.

0.0.4

  • Mark module as explicitly Safe.

0.0.3

  • First version. Released on an unsuspecting world.