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[Python-Dev] PEP for Better Control of Nested Lexical Scopes

Jeremy Hylton jeremy at alum.mit.edu
Wed Feb 22 12:14:21 CET 2006 
On 2/22/06, Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:
> Mark Russell wrote:
>
> > PEP 227 mentions using := as a rebinding operator, but rejects the
> > idea as it would encourage the use of closures.
>
> Well, anything that facilitates rebinding in outer scopes
> is going to encourage the use of closures, so I can't
> see that as being a reason to reject a particular means
> of rebinding. You either think such rebinding is a good
> idea or not -- and that seems to be a matter of highly
> individual taste.

At the time PEP 227 was written, nested scopes were contentious.  (I
recall one developer who said he'd be embarassed to tell his
co-workers he worked on Python if it had this feature :-).  Rebinding
was more contentious, so the feature was left out.  I don't think any
particular syntax or spelling for rebinding was favored more or less.

> On this particular idea, I tend to think it's too obscure
> as well. Python generally avoids attaching randomly-chosen
> semantics to punctuation, and I'd like to see it stay
> that way.

I agree.

Jeremy
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