On Jul 8, 2005, at 4:46 PM, Brett Cannon wrote:
I think having basic context managers in a stdlib module that we know for a fact that will be handy is a good idea. We should keep the list short and poignant, but we should have something for people to work off of. The ones I like below for a 'context' module are:
- builtins: with open/file
- sys: with sys.redirected_std[in|out|err]
- decimal: with decimal.Context
- os: with os.current_directory
- mutex: with mutexobj
- threading: with threading.Lock with threading.Condition with threading.Event
- bz2/zipfile/tarfile: with ...open
It is a really bad idea to codify the practice of modifying non- threadlocal global state like sys.std[in|out|err] and current directory with a context manager. A user can do it to themselves now, true, but by putting a context manager for it in the stdlib, you make it look like it'd be a local modification when it is not. I can only see confusion resulting from this. Users will inevitably try to use it like with sys.redirected_stderr(f): print "hello" print "there" instead of explicitly writing to f with print>> or write(). And that is just a terribly bad idea. It looks pretty, yes, but unless stdinouterr are made thread-local, it's just asking for trouble.
James