module Foundation.Boot.List
( length
, sum
, reverse
) where
import Foundation.Internal.Base
import Foundation.Numerical.Additive
import qualified GHC.List as List
length :: [a] -> Int
#if MIN_VERSION_base(4,8,0)
length = List.foldl' (\c _ -> c+1) 0
#else
length = loop 0
where loop !acc [] = acc
loop !acc (_:xs) = loop (1+acc) xs
#endif
sum :: Additive n => [n] -> n
sum [] = azero
sum (i:is) = loop i is
where
loop !acc [] = acc
loop !acc (x:xs) = loop (acc+x) xs
reverse :: [a] -> [a]
reverse l = go l []
where
go [] acc = acc
go (x:xs) acc = go xs (x:acc)