[Python-Dev] Defining properties - a use case for class decorators?
Phillip J. Eby
pje at telecommunity.com
Wed Oct 19 17:42:05 CEST 2005
At 07:47 PM 10/19/2005 +1000, Nick Coghlan wrote:
>Phillip J. Eby wrote:
> > Note that a "where" or "given" statement like this could make it a
> > little easier to drop lambda.
>I think the "lambda will disappear in Py3k" concept might have been what
>triggered the original 'where' statement discussion.
>The idea was to be able to lift an arbitrary subexpression out of a function
>call or assignment statement without having to worry about affecting the
>surrounding namespace, and without distracting attention from the original
>statement. Basically, let a local refactoring *stay* local.
>The discussion wandered fairly far afield from that original goal though.
>One reason it fell apart was trying to answer the seemingly simple question
>"What would this print?":
> def f():
> a = 1
> b = 2
> print 1, locals()
> print 3, locals() given:
> a = 2
> c = 3
> print 2, locals()
> print 4, locals()
It would print "SyntaxError", because the 'given' or 'where' clause should
only work on an expression or assignment statement, not print. :)
In Python 3000, where print is a function, it should print the numbers in
sequence, with 1+4 showing the outer locals, and 2+3 showing the inner
locals (not including 'b', since b is not a local variable in the nested
I don't see what's hard about the question, if you view the block as syntax
sugar for a function definition and invocation on the right hand side of an
Of course, if you assume it can occur on *any* statement (e.g. print), I
suppose things could seem more hairy.
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