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The Ref Man doesn't explicitly say anything about 
Python's left-to-right evaluation order. Strict left-
to-right was Guido's intent, though, and it comes up a 
few times per year on c.l.py (indeed, I was just 
replying to a msg asking about it).
The docs should get fleshed out.
There's also a bug:
>>> counter = 0
>>> def i():
... global counter
... counter += 1
... return counter
...
>>> {i(): i()}
{2: 1}
>>> {i(): i(), i(): i()}
{4: 3, 6: 5}
>>>
That is, key:value *pairs* are evaluated left to 
right, but within a single key:value pair, the value 
gets evaluated first. When I asked Guido about that 
some years ago, he agreed it was a bug.

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With the patch attached, this behaviour is cast into stone
(or, atleast into a SF tracker :)

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I'm attaching a suggested solution for the problem,
including documentation and reordering of dict evaluation.

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Martin, could you please review the proposed solution?

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The patch looks fine, please apply it.
It would be good to check that Jython meets all your 
expectations in this respect, and that it, in particular, 
executes all the examples in the documentation in the right 
order.
This change should *not* be backported to 2.2 IMO.

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Martin, I've checked with Jython and the examples are ok as
well.
I have applied as:
Doc/ref/ref5.tex: 1.71
Python/compile.c: 2.267
Lib/compiler/pycodegen.py: 1.62
Misc/NEWS: 1.561
Thank you!