Returns True if src and probe at least matches at the beginning till some point.

def _starts_till(src, probe, strip_comments=True):
    '''
    Returns True if src and probe at least matches at the beginning till some point.
    '''
    def _strip_comments(txt):
        '''
        Strip possible comments.
        Usually comments are one or two symbols at the beginning of the line, separated with space
        '''
        buff = txt.split(" ", 1)
        return len(buff) == 2 and len(buff[0]) < 2 and buff[1] or txt

    def _to_words(txt):
        '''
        Split by words
        '''
        return txt and [w for w in txt.strip().split(" ") if w.strip()] or txt

    no_match = -1
    equal = 0
    if not src or not probe:
        return no_match

    src = src.rstrip('\n\r')
    probe = probe.rstrip('\n\r')
    if src == probe:
        return equal

    src = _to_words(strip_comments and _strip_comments(src) or src)
    probe = _to_words(strip_comments and _strip_comments(probe) or probe)

    a_buff, b_buff = len(src) < len(probe) and (src, probe) or (probe, src)
    b_buff = ' '.join(b_buff)
    for idx in range(len(a_buff)):
        prb = ' '.join(a_buff[:-(idx + 1)])
        if prb and b_buff.startswith(prb):
            return idx

    return no_match