[Haskell-cafe] Could someone help me to understand funB?

[Magicloud Magiclouds]

Hi,

  Following code is to get a list of primes. Now it is hard for me to
understand funB. I mean I can see what it does. But I cannot see the
detailed process by every language part.

import Control.Monad

isPrime :: Integer -> Bool
isPrime i = ap funA funB i

funA :: Integer -> [Integer] -> Bool
funA x xs = all (\x' -> (mod x x') /= 0) xs

funB :: Integer -> [Integer]
funB = flip takeWhile primes . ( . join (*)) . flip (<=)

primes :: [Integer]
primes = 2 : filter isPrime [3, 5 ..]

main :: IO ()
main = print $ take 10 primes

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