[Python-Dev] PEP 343 and __context__()

[Jason Orendorff]

On 1/20/06, Nick Coghlan <ncoghlan at gmail.com> wrote:
> Jason Orendorff wrote:
> > DecimalContext has a few problems.  In code where it matters, every
> > function you write has to worry about it. (That is, you can't just
> > write __decimal_context__ = ... at the top of the file and be done
> > with it, the way you can with, say, __metaclass__.)
>
> No, you write "decimal.setcontext(...)" instead.

You seem to be implying these are roughly equal in convenience; I
disagree.  Suppose I have banking.py, in which it's important to use a
particular precision and rounding.  Now I have to put context-munging
code in every single function that banking.py exposes.  And around
every 'yield'.  Even with 'with', that's a lot of extra lines of code.

I'd much prefer to put a one-liner at the top of the file, if it were
possible (...but I don't see how, yet).

Again, none of this is likely to matter--unless you're interleaving
banking and heavy scientific calculations, which I try to avoid.  So,
not a big deal.  Thanks for the response.

> >  And
> > DecimalContext doesn't fit in with generators.
>
> It does fit actually - you simply have to remember to restore the original
> context around any invocations of yield.

Feh!  "Fit" is to "can be made to work with a bit of effort, just
don't forget to follow the rules" as Python is to C++.

-j