module HaskellWorks.Data.MQuery.ToBool where import qualified Data.DList as DL class ToBool a where toBool :: a -> Bool instance ToBool Bool where toBool :: Bool -> Bool toBool = Bool -> Bool forall a. a -> a id instance ToBool [a] where toBool :: [a] -> Bool toBool (a _:[a] _) = Bool True toBool [a] _ = Bool False instance ToBool (DL.DList a) where toBool :: DList a -> Bool toBool = [a] -> Bool forall a. ToBool a => a -> Bool toBool ([a] -> Bool) -> (DList a -> [a]) -> DList a -> Bool forall b c a. (b -> c) -> (a -> b) -> a -> c . DList a -> [a] forall a. DList a -> [a] DL.toList