{-# LANGUAGE CPP, NoImplicitPrelude #-} module Data.Foldable.Compat ( module Base #if !(MIN_VERSION_base(4,8,0)) , length , null #endif ) where import Data.Foldable as Base #if !(MIN_VERSION_base(4,8,0)) import Prelude (Bool(..), Int, (+)) -- | Test whether the structure is empty. The default implementation is -- optimized for structures that are similar to cons-lists, because there -- is no general way to do better. null :: Foldable t => t a -> Bool null = foldr (\_ _ -> False) True -- | Returns the size/length of a finite structure as an 'Int'. The -- default implementation is optimized for structures that are similar to -- cons-lists, because there is no general way to do better. length :: Foldable t => t a -> Int length = foldl' (\c _ -> c+1) 0 #endif