[Python-Dev] 'With' context documentation draft (was Re: Terminology for PEP 343 (original) (raw)

M.-A. Lemburg mal at egenix.com
Thu Jul 14 21:15:28 CEST 2005

Nick Coghlan wrote:

M.-A. Lemburg wrote:

May I suggest that you use a different name than "context" for this ?!

The term "context" is way to broad for the application scopes that you have in mind here (like e.g. managing a resource in a multi-threaded application). It's actually the broadness of the term 'context' which is appealing - the examples in the draft documentation on SF are: - resource management (synchronisation locks, generic 'closing') - HTML tag matching - Decimal arithmetic context Any earlier version used 'suite managers' (partly to avoid confusing the hell out of anyone ever exposed to Ruby's concept of blocks), but the 'context management' term seems to more clearly describe what the protocol is for.

This is exactly what I'm getting at: I can see the potential use for resource management (which is what started out the whole idea IIRC), but fail to see why you'd want to use it for anything more complicated than that.

Once you start talking about contexts (which usually refers to a combination of environment, state and location) you have to explain things like nesting, scopes, combination of different contexts, their interaction with each other, etc. etc.

Note that hiding things away in smart objects like what you call "context managers" will not make programs easier to understand, unless the specific task that such a "context manager" is simple enough to grasp by just looking at its definition in the with statement... but then you'd not call it a "context manager".

BTW, the same argument applies to decorators. Programs don't get easier to read or understand if you overload a function with lots and lots of hidden magic...

@put_all_the_smart_stuff_here def program(context): return "42"

Of course, you could do all these things and Python is not preventing you from doing so, but will life get easier ? I doubt it.

Let's keep things simple and Python nice.

-- Marc-Andre Lemburg eGenix.com

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