From: Chad Perrin <perrin@...>
Date: 2006-07-27T11:28:20+09:00
Subject: Re: For performance, write it in C

On Thu, Jul 27, 2006 at 09:09:43AM +0900, Keith Gaughan wrote:
> On Thu, Jul 27, 2006 at 08:53:18AM +0900, Keith Gaughan wrote:
> 
> > On Thu, Jul 27, 2006 at 08:33:31AM +0900, Chad Perrin wrote:
> > 
> > > Is it just me, or are there no proper closures in that example code?
> > 
> > No, Chad. There's closures in there. What you're not seeing is
> > anonymous functions, but closures are not the same as anonymous
> > functions.
> 
> Clarification: like Java, Python won't let you assign to variables in
> the outer scope, so you have to use an array or some other object to
> hack around that if you need that functionality. I know, it sucks, but
> the fact it doesn't allow you to assign to an outer scope doesn't stop
> Python from having closures, just that it doesn't trust the developer
> not to screw things up.
> 
> Here's a better example:
> 
> def foo():
>     x = [0]
>     def bar():
>         x[0] += 1
>         print x[0]
>     return bar
> 
> baz = foo()
> baz()           -> 1
> baz()           -> 2
> baz()           -> 3

That's a bit clearer -- and it does look like a proper closure.  It also
looks unnecessarily complex to implement.  Thanks for the example.

-- 
CCD CopyWrite Chad Perrin [ http://ccd.apotheon.org ]
"The ability to quote is a serviceable
substitute for wit." - W. Somerset Maugham