[Python-Dev] accumulator display syntax

[Alex Martelli]

On Friday 17 October 2003 06:12 pm, Skip Montanaro wrote:
>     Greg> What you're proposing hijacks the indexing syntax and uses it to
>     Greg> mean something completely different from indexing, which is a
> much Greg> bigger change, and potentially a very confusing one.
>
>     Greg> So, no, sorry, it doesn't overcome my objection!
>
> I agree.  Any expression bracketed by '[' and ']', no matter how many other
> clues to the ultimate result it might contain, ought to result in a list as
> far as I'm concerned.

Hmmm, how is, e.g.
    foo[x*x for x in bar]
any more an "expression bracketed by [ and ]" than, say,
    foo = {'wot': 'tow'}
    foo['wot']
...?  Yet the latter doesn't involve any lists that I can think of.  Nor do
I see why the former need "mean something completely different from
indexing" -- it means to call foo's __getitem__ with the appropriately
constructed object, just as e.g. foo[ 'va':23:2j, {'zip':'zop'}:45:(3,4) ]
today calls it with a tuple of two weird slice objects (and doesn't
happen to involve any lists whatsoever).


Alex