[Python-3000] PEP 3113 (Removal of Tuple Parameter Unpacking)

[Christian Tanzer]

Ka-Ping Yee <python at zesty.ca> wrote

> On 3/4/07, Raymond Hettinger <python at rcn.com> wrote:
> > FWIW, I would like the feature to be kept.  I've found it useful in that it
> > documents the function signature more completely when dealing
> > with arguments that are already pre-packed into tuples
>
> I just noticed that this has a more noticeable effect on lambda, since
> you don't have room for another statement to do the unpacking.
>
> To sort a dictionary by value, you can currently write
>
>     sorted(dict.items(), key=lambda (key, value): value)
>
> Without tuple unpacking, this idiom becomes
>
>     sorted(dict.items(), key=lambda item: item[1])
>
> obscuring the fact that the item is a (key, value) pair.

Oooops. I'd pretty much ignored the discussion because I thought that
I didn't use tuple parameter unpacking anyway.

Unfortunately, I use it quite a bit with lambda. I shudder at the
thought how those are going to look without tuple unpacking.

FWIW, I always liked the `parameter passing is assignment` semantics
of Python. I sure hope nobody is going to start a crus^H^H^H^HPEP to
remove tuple unpacking in general from the language!

-- 
Christian Tanzer                                    http://www.c-tanzer.at/