Typed version of Python code for the (for-loop,modulo) benchmark

primes_below.py

"""Benchmark http://stackoverflow.com/questions/11641098/interpreting-a-benchmark-in-c-clojure-python-ruby-scala-and-others#comment15487214_11641098
"""
import cython

@cython.locals(n=int,j=int)
def is_prime(n):
    for j in xrange(2, n):
        if n % j == 0:
            return False
    return True

def primes_below(x):
    return [(j-6, j) for j in xrange(9, x + 1) if is_prime(j) and is_prime(j-6)]

def main(argv):
    n = int(argv[1]) if len(argv) > 1 else 100*1000
    print(primes_below(n))

if __name__=="__main__":
    import sys
    sys.exit(main(sys.argv))