Variable defined with with-statement available outside of with-block?

Consider the following example:

with open('a.txt') as f:
    pass
# Is f supposed to be defined here?

I have read the language docs (2.7) for with-statement as well as PEP-343, but as far as I can tell they don't say anything on this matter.

In CPython 2.6.5 f does seem to be defined outside of the with-block, but I'd rather not rely on an implementation detail that could change.

Solution 1:

Yes, the context manager will be available outside the with statement and that is not implementation or version dependent. with statements do not create a new execution scope.

Solution 2:

the with syntax:

with foo as bar:
    baz()

is approximately sugar for:

try:
    bar = foo.__enter__()
    baz()
finally:
    if foo.__exit__(*sys.exc_info()) and sys.exc_info():
        raise

This is often useful. For example

import threading
with threading.Lock() as myLock:
    frob()

with myLock:
    frob_some_more()

the context manager may be of use more than once.