module ADP.Fusion.Empty where
import Data.Array.Repa.Index
import Data.Strict.Maybe
import Data.Strict.Tuple
import Prelude hiding (Maybe(..))
import qualified Data.Vector.Fusion.Stream.Monadic as S
import Data.Array.Repa.Index.Subword
import ADP.Fusion.Classes
data Empty = Empty
empty = Empty
instance
( ValidIndex ls Subword
) => ValidIndex (ls :!: Empty) Subword where
validIndex (ls:!:Empty) abc ij@(Subword (i:.j)) = i==j && validIndex ls abc ij
instance Build Empty
instance
( Elms ls Subword
) => Elms (ls :!: Empty) Subword where
data Elm (ls :!: Empty) Subword = ElmEmpty !(Elm ls Subword) !() !Subword
type Arg (ls :!: Empty) = Arg ls :. ()
getArg !(ElmEmpty ls () _) = getArg ls :. ()
getIdx !(ElmEmpty _ _ i) = i
instance
( Monad m
, Elms ls Subword
, MkStream m ls Subword
) => MkStream m (ls:!:Empty) Subword where
mkStream !(ls:!:Empty) Outer !ij@(Subword (i:.j))
= S.map (\s -> ElmEmpty s () (subword i j))
$ S.filter (\_ -> i==j)
$ mkStream ls Outer ij