GADTContext.hs

{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE ImplicitParams #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE RankNTypes         #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TupleSections #-}

data StackItem a where
  Snum :: forall a. Fractional a => a -> StackItem a
  Sop  :: OpDesc -> StackItem a
deriving instance Show a => Show (StackItem a)

type MPI = ?mpi_secret :: MPISecret

mkPoli = mkBila . map ((,,(),,()) <$> P.base <*> P.pos <*> P.form)

data MaybeDefault v where
    SetTo :: forall v . ( Eq v, Show v ) => !v -> MaybeDefault v
    SetTo4 :: forall v a. (( Eq v, Show v ) => v -> MaybeDefault v
                                            -> a -> MaybeDefault [a])
    TestParens  :: (forall v . (Eq v) => MaybeDefault v)
    TestParens2 :: (forall v . ((Eq v)) => MaybeDefault v)
    TestParens3 :: (forall v . (((Eq v)) => (MaybeDefault v)))
    TestParens4 :: (forall v . (((Eq v)) => (MaybeDefault v -> MaybeDefault v)))

data T a where
  K1 :: forall a. Ord a => { x :: [a], y :: Int } -> T a
  K2 :: forall a. ((Ord a)) => { x :: ([a]), y :: ((Int)) } -> T a
  K3 :: forall a. ((Ord a)) => { x :: ([a]), y :: ((Int)) } -> (T a)
  K4 :: (forall a. Ord a => { x :: [a], y :: Int } -> T a)

[t| Map.Map T.Text $tc |]

bar $( [p| x |] ) = x