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

[Stephen J. Turnbull]

>>>>> "Jim" == Jim Jewett <jimjjewett at gmail.com> writes:

    Jim> Nick Coghlan asked Marc-Andre Lemburg:

    >> There's clearly something that bothers you about this though,
    >> and I'd like to understand what it is. Does the term 'context'
    >> carry additional, more specific, connotations for you that I'm
    >> simply not taking into account?

    Jim> To me, a context is much larger than a single object.

To me, "*the* context" can be as small as exactly the subset of the
environment that you need to manage to ensure correct behavior of the
object(s) being managed.  Eg, in quoting in email "preserving context"
does not require quoting the whole message referenced in most cases.
You only need to quote enough to ensure that the author's intention is
conveyed to your readers.

However, a "context manager" need not manage the whole context of the
calling module, only those parts the encapsulated code might damage or
misinterpret.  Continuing with the email quoting example, if I then go
on to quote a different part of the same email you did, I don't (in
general) have to preserve the context that you did, only that of the
part that I quote.

I don't know that that should be convincing to those who have other
associations for the word "context", but maybe it's a useful mnemonic
and analogy for tutorial writers.

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