[Python-Dev] Re: syntactic shortcut - unpack to variably sizedlist

[Carlos Ribeiro]

On Sun, 21 Nov 2004 03:34:34 +1000, Nick Coghlan <ncoghlan at iinet.net.au> wrote:
> Raymond Hettinger wrote:
> > Also, the pep would likely kill the remote, but non-zero chance of ever
> > getting the a,b,*c syntax.  IOW, the pep may be a step backwards.
> 
> Officially killing that syntax was actually one of the stated goals of the PEP.
> 
> However, the PEP editors would be well within their rights to reject the draft
> as 'lacking focus'. I wouldn't be offended given the whole 20 minutes it took to
> write it :)

By itself, both alternatives presented in the implementation do not
"kill" the a,b,*c syntax. I prefer to argue that list.pop(slice) and
iunpack(...) do facilitate future support for it, while at the same
time removing immediate pressure by providing an easy alternative to
support one version of the idiom that still uses current Python
syntax.

Other potential argument against is that the PEP provides two ways to
make it, contrary to the "one way to do it" motto. But both cases,
while related, are really focused on solving two different problems;
one is a generic solution for iterables (which happend to include a
whole bunch of objects, including tuples and lists), and the other is
an optimization for mutable lists. There's no reason not to support
both (of course, if the whole point of the PEP is accepted).

-- 
Carlos Ribeiro
Consultoria em Projetos
blog: http://rascunhosrotos.blogspot.com
blog: http://pythonnotes.blogspot.com
mail: carribeiro at gmail.com
mail: carribeiro at yahoo.com