[Python-Dev] Re: Shorthand for lambda

[Bob Ippolito]

On Mar 23, 2005, at 1:16 PM, Ka-Ping Yee wrote:

> On Wed, 23 Mar 2005, Reinhold Birkenfeld wrote:
>> What does you implementation do for this:
>>
>>>>> somevar = False
>>>>> filter(_ and False, numbers)
>
> It fails.  (For the same reason that __len__ doesn't work --
> Python insists that __nonzero__ must return an int.)  Though
> i must say i have no idea what you are trying to do here.
> If you filter on False, you'll always get an empty list.

Similarly, appscript provides function versions of operators named such 
as AND and OR.  I suppose there could be a length one as well (in 
AppleScript terminology, it would be called count), or you could 
technically denote it as __len__(), but that's quite ugly.

I had implemented something quite similar to this a long time ago, but 
considered it "evil" and never used it for anything:

http://tinyurl.com/6ft4h

-bob