@hackage trivial-constraint0.2.0.0

A class / constraint that any type fulfills

Categories
License
GPL-3.0-only
Maintainer
sagemuej@smail.uni-koeln.de
Links
- Homepage
- Documentation
- No source repository
Versions
- 0.7.0.0 Fri, 7 May 2021
- 0.6.0.0 Fri, 12 Jul 2019
- 0.5.1.0 Mon, 3 Jun 2019
- 0.5.0.0 Fri, 24 May 2019
- 0.4.0.0 Sat, 23 Jan 2016
- 0.3.0.0 Fri, 27 Feb 2015

Installation
In your cabal file:
Dependencies (1)
- base >=4 && <5
Dependents (5)
@hackage/polysemy-keyed-state, @hackage/functor-combinators, @hackage/acme-everything, @hackage/manifolds, @hackage/constrained-categories

Since GHC 7.4, constraints are first-class: we have the constraint kind, and thus type-classes have a kind such as * -> Constraint.

These can be used as parameters to data types. They also can be combined quite nicely,

type NewConstraint a = (Constraint1 a, Constraint2 a)

however you always need to start with a plain old type class when building constraints.

This library provides a type class that is not really a constraint at all, so you can "start from zero" with building up a custom constraint.