python regex lazy re.compile

import re


class _Lazy(object):

    __slots__ = ['pattern', 'kwargs', 'compiled']

    def __init__(self, pattern, **kwargs):
        self.pattern = pattern
        self.kwargs = kwargs
        self.compiled = None

    def __getattr__(self, name):
        if self.compiled is None:
            self.compiled = re.compile(self.pattern, **self.kwargs)
        return self.compiled.__getattribute__(name)


def lazy_compile(pattern, **kwargs):
    return _Lazy(pattern, **kwargs)

Use:

In [2]:

In [2]: lazy_compile(r'[a-z]')
Out[2]: <__main__._Lazy at 0x11095c088>

In [3]: c = lazy_compile(r'[a-z]')

In [4]: c.findall('sdsd sdsds aq, $A fddf')
Out[4]: ['s', 'd', 's', 'd', 's', 'd', 's', 'd', 's', 'a', 'q', 'f', 'd', 'd', 'f']