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Securing a future for anonymous functions in Python

Alex Martelli aleaxit at yahoo.com
Fri Dec 31 12:38:24 EST 2004 
Paul L. Du Bois <polytope at gmail.com> wrote:
   ...
> are all unsupported.  I'm sorry if google groups eats my leading
> whitespace; I've one-lined things to reduce the effect.

It does/did, so let me repost while fixing it since this is truly,
deliciously evil:

> def fn(gen):
>     """Turns a generator expression into a callable."""
>     def anonymous(*args): return gen.next()
>     return anonymous
> 
> def args():
>     """Works with fn(); yields args passed to anonymous()."""
>     while True: yield sys._getframe(2).f_locals['args']
> 
> args = args()
> 
> foo = fn(a + b * c for (a,b,c) in args)
> assert foo(3,4,5) == 3+4*5
> assert foo(4,5,6) == 4+5*6

Paul, you really SHOULD have posted this BEFORE I had to send in the
files for the 2nd ed's Coobook... this gets my vote for the most
delightful abuse of sys._getframe even (and I've seen quite a few;-).

Kudos!!!


Alex
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