Hi.
It would be great to be able to reverse usage/definition parts in haskell-way with "where" keyword. Since Python 3 would miss lambda, that would be extremly useful for creating readable sources.
Usage could be something like:
>>> res = [ f(i) for i in objects ] where: >>> def f(x): >>> #do something
Hmm, this is actually a really interesting idea. Avoiding accidental namespace conflicts is certainly one of the advantages of using lambdas.
This idea has the virtue of being able to do the same thing, but have full access to Python's function syntax and assignment statements in the 'expression local' suite.
In fact, any subexpressions in a complicated expression can be extracted and named for clarity without fear of screwing up the containing namespace, which would be an enormous boon for software maintainers.
It also allows the necessary but uninteresting setup for an expression to be moved "out of the way", bringing the expression that does the real work to prominence.
From the interpreter's point of view, the meaning would probably be something like:
namespace = locals() exec where_suite in globals(), namespace exec statement in globals(), namespace res = namespace["res"] del namespace
Making the 'where' clause part of the grammar for the assignment statement should be enough to make the above example parseable, too.
The clause might actually make sense for all of the simple statement forms in the grammar which contain an expression:
expression statement
assignment statement
augmented assignment statement
del statement
print statement
return statement
yield statement
raise statement
exec statement
The clause really isn't appropriate for break, continue, import or global statements, as they don't contain any expressions :)
For compound statements, a where clause probably isn't appropriate, as it would be rather unclear what the where clause applied to.
Cheers, Nick.
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Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
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http://boredomandlaziness.skystorm.net
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