The trivial-constraint package
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. Also its opposite (a constraint that no type can ever fulfill).
|Versions||0.1.0.0, 0.2.0.0, 0.3.0.0, 0.4.0.0|
|Dependencies||base (>=4.5 && <5) [details]|
|Uploaded||Sat Jan 23 00:18:44 UTC 2016 by leftaroundabout|
|Downloads||602 total (8 in the last 30 days)|
|Status||Docs uploaded by user
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