mrstephengross wrote:
>> What you can't do (that I really miss) is have a tree of assign-and-test
>> expressions:
>> import re
>> pat = re.compile('some pattern')
>> if m = pat.match(some_string):
>> do_something(m)
>
> Yep, this is exactly what I am (was) trying to do. Oh well.... Any
> clever ideas on this front?
I worked around it by defining a separate thigamabob with a "result"
property. A method of the thigamabob internally performs the
assignment, and returns a boolean result. The body of each branch in
the tree can then retrieve the result object from the thigamabob.
Here's an example hard-coded to match strings against patterns, but I
think the idea should be extensible to other kinds of assign-and-test
situations.
# Just for the sake of this post.
def do_something(m): pass
def do_other_thing(m): pass
def do_default_thing(): pass
import re
class Matcher(object):
def __call__(self, pattern, string):
self.result = pattern.match(string)
if __name__ == '__main__':
pat = re.compile('some pattern')
match = Matcher()
if match(pat, 'a'):
do_something(match.result)
elif match(pat, 'b'):
do_other_thing(match.result)
else:
do_default_thing()
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