combinators.py

from itertools import takewhile

def combinator_style(xs):
    return Combinators(xs).chain().R(
        takewhile, lambda x: x < 7
    ).R(
        filter, lambda x: x < 2
    ).R(
        map, lambda x: 4 * x
    ).value()
    
assert combinator_style(range(10)) == [0, 4]