Revision as of 23:07, 24 July 2021 by Ysangkok (→Further reading: rebindable syntax in the ghc users guide)
With a bit of work, we can define a ternary conditional operator in Haskell. Courtesy of Andrew Baumann. This appears only to be valid in Hugs?
import qualified Prelude data Cond a = a : a infixl 0 ? infixl 1 : (?) :: Prelude.Bool -> Cond a -> a Prelude.True ? (x : _) = x Prelude.False ? (_ : y) = y test = 1 Prelude.< 2 ? "yeah" : "no!"
Another version that works in GHC.
data Cond a = a :? a infixl 0 ? infixl 1 :? (?) :: Bool -> Cond a -> a True ? (x :? _) = x False ? (_ :? y) = y test = 1 < 2 ? "Yes" :? "No"