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{-# LANGUAGE GADTs #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE TemplateHaskell #-}
module Main (main) where
import Language.Haskell.TH
infixr 7 :***:
data GADT a where
Prefix :: Int -> Int -> GADT Int
(:***:) :: Int -> Int -> GADT Int
$(do gadtName <- newName "GADT2"
prefixName <- newName "Prefix2"
infixName <- newName ":****:"
a <- newName "a"
return [ DataD [] gadtName [KindedTV a () StarT] Nothing
[ GadtC [prefixName]
[ (Bang NoSourceUnpackedness NoSourceStrictness,ConT ''Int)
, (Bang NoSourceUnpackedness NoSourceStrictness,ConT ''Int)
] (AppT (ConT gadtName) (ConT ''Int))
, GadtC [infixName]
[ (Bang NoSourceUnpackedness NoSourceStrictness,ConT ''Int)
, (Bang NoSourceUnpackedness NoSourceStrictness,ConT ''Int)
] (AppT (ConT gadtName) (ConT ''Int))
] []
, InfixD (Fixity 7 InfixR) infixName
])
$(return [])
deriving instance Show (GADT2 a)
main :: IO ()
main = do
-- Verify that infix GADT constructors reify correctly
putStrLn $(reify ''GADT >>= stringE . pprint)
putStrLn $(reify '(:***:) >>= stringE . pprint)
-- Verify that reifyFixity returns something with (:***:)
-- (but not with Prefix, since it has no fixity declaration)
putStrLn $(reifyFixity 'Prefix >>= stringE . show)
putStrLn $(reifyFixity '(:***:) >>= stringE . show)
-- Verify that spliced-in GADT infix constructors are actually infix
print (1 :****: 4)
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