import Prelude hiding (take)

-- Evaluating expressions:

f x = 1
h = h


-- Returns an ascending list of integers
-- from 0 --> 0 : 1 : 2 : 3 : ...
from :: Int -> [Int]
from n = n : from (n + 1)

-- Returns the first n elements of a list
take :: Int -> [a] -> [a]
take n xs | n == 0    = []
          | otherwise = case xs of
                          []     -> []
                          (x:xs) -> x : take (n-1) xs

-- Sieve of Eratosthenes: filter multiples of initial elements
sieve :: [Int] -> [Int]
sieve (p:xs) = p : sieve (filter (\x -> x `mod` p > 0) xs)

-- The infinite list of all prime numbers:
primes :: [Int]
primes = sieve (from 2)