error handler

anonymous-gist.py

from contextlib import contextmanager
import re
from functools import partial

@contextmanager
def handler(f):
    try:
        yield
    except Exception as e:
        if not f(e):
            raise e
    
        
def regex(expr, e):
    p = re.compile(expr)
    return p.search(e.message)

with handler(partial(regex, 'foo')):
    x = 1
    raise Exception('oh noes foo happened!') # this will be caught because regex matches

Can you give a concrete example of where you'd use this? I'm failing to grok.