↧
Answer by Greg Bacon for Lifting class instance in Haskell
The generalized newtype deriving extension is what you want here:{-# LANGUAGE GeneralizedNewtypeDeriving #-}module Main wherenewtype SomeType a = SomeCons a deriving (Num, Show, Eq)main = do let a =...
View ArticleAnswer by Raoul Supercopter for Lifting class instance in Haskell
GHC implements what you want : Extensions to the deriving mecanism.These modifications are often shown for future standard language extension (As seen on haskell' wiki)To Enable this extension, you...
View ArticleLifting class instance in Haskell
Is there a way to "lift" a class instance in Haskell easily?I've been frequently needing to create, e.g., Num instances for some classes that are just "lifting" the Num structure through the type...
View Article