[Python-ideas] Bytecode for calling function with keyword arguments

[Niki Spahiev]

On 21.04.2016 20:28, Serhiy Storchaka wrote:
> On 21.04.16 19:00, Chris Angelico wrote:
>> On Fri, Apr 22, 2016 at 1:52 AM, Serhiy Storchaka
>> <storchaka at gmail.com> wrote:
>>> 2. Since the number of keyword arguments is obtained from tuple's
>>> size, new
>>> CALL_FUNCTION opcode needs only the number of positional arguments. It's
>>> argument is simpler and needs less bits (important for wordcode).
>>
>> What about calls that don't include any keyword arguments? Currently,
>> no pushing is done. Will you have two opcodes, one if there are kwargs
>> and one if there are not?
>
> Yes, we need either two opcodes, or a falg in the argument. I prefer the
> first approach to keep the argument short and simple.
>
>> Also: How does this interact with **dict calls?
>
> For now we have separate opcode for calls with **kwargs. We will have
> corresponding opcode with new way to provide keyword arguments.
>
> Instead of 4 current opcodes we will need at most 8 new opcodes. May be
> less, because calls with *args or **kwargs is less performance critical,
> we can pack arguments in a tuple and a dict by separate opcodes and call
> a function just with a tuple and a dict.

We can limit second argument (number of kw args) to be 0 or 1 only. With 
1 meaning single tuple with the names.

Niki