module Control.Egison.Matcher.Pair
( Pair(..)
, tuple2
, tuple2M
)
where
import Control.Monad ( MonadPlus(..) )
import Control.Monad.Search
import Control.Egison.Match
import Control.Egison.Matcher
import Control.Egison.QQ
data Pair m1 m2 = Pair m1 m2
instance (Matcher m1 t1, Matcher m2 t2) => Matcher (Pair m1 m2) (t1, t2)
tuple2 :: Pattern (PP, PP) (Pair m1 m2) (t1, t2) (t1, t2)
tuple2 _ (Pair m1 m2) (t1, t2) = pure (t1, t2)
tuple2M :: Pair m1 m2 -> (t1, t2) -> (m1, m2)
tuple2M (Pair m1 m2) _ = (m1, m2)