[Python-ideas] namedtuple literals [Was: RE a new namedtuple]

MRAB python at mrabarnett.plus.com
Tue Jul 25 13:49:30 EDT 2017

On 2017-07-25 02:57, Nick Coghlan wrote:
> On 25 July 2017 at 02:46, Michel Desmoulin <desmoulinmichel at gmail.com> wrote:
>> Le 24/07/2017 à 16:12, Nick Coghlan a écrit :
>>> On 22 July 2017 at 01:18, Guido van Rossum <guido at python.org> wrote:
>>>> Honestly I would like to declare the bare (x=1, y=0) proposal dead. Let's
>>>> encourage the use of objects rather than tuples (named or otherwise) for
>>>> most data exchanges. I know of a large codebase that uses dicts instead of
>>>> objects, and it's a mess. I expect the bare ntuple to encourage the same
>>>> chaos.
>> This is the people working on big code base talking.
> Dedicated syntax:
>      (x=1, y=0)
> New builtin:
>      ntuple(x=1, y=0)
> So the only thing being ruled out is the dedicated syntax option,
> since it doesn't let us do anything that a new builtin can't do, it's
> harder to find help on (as compared to "help(ntuple)" or searching
> online for "python ntuple"), and it can't be readily backported to
> Python 3.6 as part of a third party library (you can't easily backport
> it any further than that regardless, since you'd be missing the
> order-preservation guarantee for the keyword arguments passed to the
> builtin).

I think it's a little like function arguments.

Arguments can be all positional, but you have to decide in what order 
they are listed. Named arguments are clearer than positional arguments 
when calling functions.

So an ntuple would be like a tuple, but with names (attributes) instead 
of positions.

I don't see how they could be compatible with tuples because the 
positions aren't fixed. You would need a NamedTuple where the type 
specifies the order.

I think...

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