Created
May 11, 2012 04:15
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Example of overloading if-then-else in Haskell
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{-# LANGUAGE RebindableSyntax #-} | |
import Prelude | |
data Height = Tall | Short | |
class IfThenElse b where | |
ifThenElse :: b -> a -> a -> a | |
instance IfThenElse Bool where | |
ifThenElse True t _ = t | |
ifThenElse False _ f = f | |
instance IfThenElse Height where | |
ifThenElse Tall t _ = t | |
ifThenElse Short _ f = f | |
main = do | |
putStrLn $ if Tall then "A" else "B" | |
putStrLn $ if False then "C" else "D" |
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