[Python-Dev] PEP 267 -- is the semantics change OK?

Sat Oct 22 00:48:34 CEST 2005

On 10/21/05, Jim Jewett <jimjjewett at gmail.com> wrote:
> (In http://mail.python.org/pipermail/python-dev/2005-October/057501.html)
> Neil Schemenauer suggested PEP 267 as an example of something that
> might be easier with the AST compiler.
>> As written, PEP 267 does propose a slight semantics change -- but it
> might be an improvement, if it is acceptable.

No, it does not. PEP 267 suggests a way to preserve the existing
semantics. You could probably come up with a much simpler approach if
you agreed to change semantics.
Jeremy
> Today, after
>> from othermod import val1
> import othermod
> val2 = othermod.val2
> othermod.val3 # Just making sure it was referenced early
>> othermod.val1 = "new1"
> othermod.val2 = "new2"
> othermod.val3 = "new3"
>> print val1, val2, othermod.val3
>> The print statement will see the updated val3, but will still have
> the original values for val1 and val2.
>> Under PEP267, all three variables would be compiled to a slot
> access in othermod, and would see the updated objects.
>> In many cases, this would be a *good* thing. It might allow
> reload to be rewritten to do what people expect. On the other
> hand, it would be a change. Would it be an acceptable change?
>> -jJ
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