re.py 文件源码

def __init__(self, lexicon, flags=0):
        from sre_constants import BRANCH, SUBPATTERN
        self.lexicon = lexicon
        # combine phrases into a compound pattern
        p = []
        s = sre_parse.Pattern()
        s.flags = flags
        for phrase, action in lexicon:
            gid = s.opengroup()
            p.append(sre_parse.SubPattern(s, [
                (SUBPATTERN, (gid, sre_parse.parse(phrase, flags))),
                ]))
            s.closegroup(gid, p[-1])
        p = sre_parse.SubPattern(s, [(BRANCH, (None, p))])
        self.scanner = sre_compile.compile(p)