> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:users-
> [EMAIL PROTECTED] On Behalf Of Sylvain Hellegouarch
> Sent: Tuesday, July 10, 2007 12:54 PM
> To: Discussion of IronPython
> Subject: Re: [IronPython] Hosting IronPython 2.X in .NET app
>
> Curt Hagenlocher a écrit :
> > On 7/10/07, *Curt Hagenlocher* <[EMAIL PROTECTED]
> > <mailto:[EMAIL PROTECTED]>> wrote:
> >
> > On 7/10/07, *Dino Viehland* < [EMAIL PROTECTED]
> > <mailto:[EMAIL PROTECTED]>> wrote:
> >
> > Major things we know we still have to do include yield
> > expressions (sorry, there's probably a technical term for
> them)
> >
> > Closures :P.
> >
> >
> > Doh! I'm so retarded that I misspelled "generators" :(.
> >
> > Apparently I've been reading too much about Ruby lately...
>
>
> Not to worry :)
> However the question stands, will Python support closures (or does it
> already via lambda expressions?)
>
> (/me is lame at language theory)
>
> - Sylvain
Closures have existed in Python since version 2.1 or so:
def f():
x = 5
return lambda: x
closure = f()
print closure() # prints 5
Here, the anonymous inner function returned by f is able to refer to variables
defined in outer scopes.
As for the Python 3000 question --
The one current limitation is that you cannot rebind names defined in outer
scopes. That is, the following code does not work as expected:
def f():
x = 5
def g():
x = 7 # x is local to g here
You could use the "global" statement to indicate that x is a global despite it
being assigned to inside the function, but there was no equivalent way to
indicate that x refers to a variable in an outer, but non-global, scope. Python
3000 will introduce the "nonlocal" statement that works like the global
statement to fill this gap. As usual, the best source is the relevant PEP:
http://www.python.org/dev/peps/pep-3104/
Hope this helps.
--
Jacob Lee
SDE Intern, Dynamic Language Runtime
<[EMAIL PROTECTED]>
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