id, ($), (.) and \ aren’t introduced until later in the text, using concepts only from 9.1 and earlier, one answer would be: applyAll :: [(a -> a)] -> a -> a applyAll = flip (foldr aux) where aux f x = f x

## 4 responses to “Exercise 9.5”

applyAll fs x = foldr id x fs

applyAll fs x = foldr ($) x fs

applyAll = foldr (.) id

id, ($), (.) and \ aren’t introduced until later in the text, using concepts only from 9.1 and earlier, one answer would be:

applyAll :: [(a -> a)] -> a -> a

applyAll = flip (foldr aux)

where aux f x = f x