On Sat, Jul 07, 2007 at 01:08:15PM -0400, Terry Reedy wrote: > > "Nick Coghlan" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] > | Georg is correct. A list comprehension like: > | > | [(x * y) for x in seq1 for y in seq2] > | > | expands to the following in 2.x (% prefixes the compiler's hidden > | variables): > | > | %n = [] > | for x in seq1: > | for y in seq2: > | %n.append(x*y) # Special opcode, not a normal call > | > | In py3k it expands to: > | > | def <anon>(outermost): > | %0 = [] > | for x in outermost: > | for y in seq2: > | %0.append(x*y) # Special opcode, not a normal call > | return %0 > | %n = <anon>(seq1) > > Why not pass both seq1 *and* seq2 to the function so both become locals? > The difference of treatment is quite surprising.
I'd be curious if there is anyway to preserve the existing behaviour;
class foo:
some_list = ('blacklist1', 'blacklist2')
known_bad = some_list += ('blah',)
locals().update([(attr, some_callable) for attr in some_list])
is slightly contrived, but I use similar code quite often for method
generation- both for tests, and standard enough objects. Realize I
could do the same via metaclasses, but it's an extra step and not
nearly as easy/friendly imo.
So... anyway to preserve that trick under py3k?
~harring
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