Can I use python with statement for conditional execution?

Question

I'm trying to write code that supports the following semantics:

with scope('action_name') as s:
  do_something()
  ...
do_some_other_stuff()

The scope, among other things (setup, cleanup) should decide if this section should run.
For instance, if the user configured the program to bypass 'action_name' than, after Scope() is evaluated do_some_other_stuff() will be executed without calling do_something() first.
I tried to do it using this context manager:

@contextmanager
def scope(action):
  if action != 'bypass':
    yield

but got RuntimeError: generator didn't yield exception (when action is 'bypass').
I am looking for a way to support this without falling back to the more verbose optional implementation:

with scope('action_name') as s:
  if s.should_run():
    do_something()
    ...
do_some_other_stuff()

Does anyone know how I can achieve this?
Thanks!

P.S. I am using python2.7

EDIT:
The solution doesn't necessarily have to rely on with statements. I just didn't know exactly how to express it without it. In essence, I want something in the form of a context (supporting setup and automatic cleanup, unrelated to the contained logic) and allowing for conditional execution based on parameters passed to the setup method and selected in the configuration.
I also thought about a possible solution using decorators. Example:

@scope('action_name') # if 'action_name' in allowed actions, do:
                      #   setup()
                      #   do_action_name()
                      #   cleanup()
                      # otherwise return
def do_action_name()
  do_something()

but I don't want to enforce too much of the internal structure (i.e., how the code is divided to functions) based on these scopes.
Does anybody have some creative ideas?

Answer 1

You're trying to modify the expected behaviour of a basic language construct. That's never a good idea, it will just lead to confusion.

There's nothing wrong with your work-around, but you can simplify it just a bit.

@contextmanager 
def scope(action): 
  yield action != 'bypass'

with scope('action_name') as s: 
  if s: 
    do_something() 
    ... 
do_some_other_stuff() 

Your scope could instead be a class whose __enter__ method returns either a useful object or None and it would be used in the same fashion.