-- | -- Module : Data.List.InnToOut.Basic -- Copyright : (c) OleksandrZhabenko 2019 -- License : MIT -- -- Maintainer : olexandr543@yahoo.com -- -- Various additional operations on lists -- module Data.List.InnToOut.Basic ( -- * Operations to apply a function or different functions (some can create an inner list) to an element of the outer list mapI , mapI2 ) where -- | Function that applies additional function @f :: a -> [a]@ to @a@ if @p a = True@ mapI :: (a -> Bool) -> (a -> [a]) -> [a] -> [a] mapI p f = concatMap (\x -> if p x then f x else [x]) {-#INLINE mapI#-} -- | Function that applies additional function @f :: a -> b@ to @a@ if @p a = True@ and otherwise another function @g :: a -> [b]@ to @[a]@ to obtain @[b]@ mapI2 :: (a -> Bool) -> (a -> b) -> (a -> [b]) -> [a] -> [b] mapI2 p f g = concatMap (\x -> if p x then [f x] else g x) {-#INLINE mapI2#-}