libghc-ghc-typelits-knownnat-dev binary package in Ubuntu Lunar amd64
A type checker plugin for GHC that can derive "complex" KnownNat
constraints from other simple/variable KnownNat constraints. i.e. without
this plugin, you must have both a KnownNat n and a KnownNat (n+2)
constraint in the type signature of the following function:
.
f :: forall n . (KnownNat n, KnownNat (n+2)) => Proxy n -> Integer
f _ = natVal (Proxy :: Proxy n) + natVal (Proxy :: Proxy (n+2))
.
Using the plugin you can omit the KnownNat (n+2) constraint:
.
f :: forall n . KnownNat n => Proxy n -> Integer
f _ = natVal (Proxy :: Proxy n) + natVal (Proxy :: Proxy (n+2))
.
The plugin can derive KnownNat constraints for types consisting of:
.
* Type variables, when there is a corresponding KnownNat constraint
.
* Type-level naturals
.
* Applications of the arithmetic expression: +,-,*,^
.
* Type functions, when there is either:
.
1. a matching given KnownNat constraint; or
.
2. a corresponding KnownNat<N> instance for the type function
.
To use the plugin, add the
.
OPTIONS_GHC -fplugin GHC.TypeLits.
.
Pragma to the header of your file.
.
This package provides a library for the Haskell programming language.
See http://
Publishing history
Date | Status | Target | Component | Section | Priority | Phased updates | Version | ||
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2022-12-28 04:09:00 UTC | Published | Ubuntu Lunar amd64 | release | universe | haskell | Optional | 0.7.7-1build1 | ||
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Deleted | Ubuntu Lunar amd64 | proposed | universe | haskell | Optional | 0.7.7-1build1 | |||
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2022-12-28 04:21:16 UTC | Superseded | Ubuntu Lunar amd64 | release | universe | haskell | Optional | 0.7.6-1 | ||
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