for in URLRX finditer tweet fro to span url group res tweet prev fro p

    for m in URLRX.finditer(tweet):
        (fro, to) = m.span()
        url = m.group(1)
        res += tweet[prev:fro]
        prev = to
        for (regex, handler) in URLSOLVERS:
            match = regex.match(url)
            if match:
                res += handler(match)
                break
        for (mo,mf) in MAPPERS:
            mx = mo.match(url)
            if mx:
                res += mf(mx)
                break
    tweet = res + tweet[prev:]