Created
November 14, 2015 23:52
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Not quite sure how to implement
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| {-# LANGUAGE DataKinds #-} | |
| {-# LANGUAGE KindSignatures #-} | |
| {-# LANGUAGE TypeOperators #-} | |
| {-# LANGUAGE GADTs #-} | |
| {-# LANGUAGE ScopedTypeVariables #-} | |
| {-# LANGUAGE PolyKinds #-} | |
| module Lits where | |
| import GHC.TypeLits | |
| import Data.Proxy | |
| import Prelude hiding (showList) | |
| -- I have no idea how to write this... | |
| -- fromList :: forall n a . SomeNat n => [a] -> List n a | |
| -- fromList [] = Nil | |
| -- fromList (x:xs) = Cons x (fromList xs) | |
| toList :: List n a -> [a] | |
| toList Nil = [] | |
| toList (Cons x xs) = x : toList xs | |
| data List :: Nat -> * -> * where | |
| Cons :: a -> List (n-1) a -> List n a | |
| Nil :: List 0 a | |
| instance Show a => Show (List n a) where | |
| show = show . toList |
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