Parens do create a tuple

[Steven D'Aprano]

On Mon, 11 Apr 2016 12:51 pm, Random832 wrote:

> On Sun, Apr 10, 2016, at 22:32, Steven D'Aprano wrote:
>> def func(arg1, arg2, arg3):
>>     pass
>> 
>> func(1, 2, 3)
>> 
>> does not create a tuple (1, 2, 3) anywhere in its execution.
> 
> Well, the second argument to PyObject_Call and function_call is a tuple,
> which had to come from somewhere.

It didn't come from any Python language feature. It is a purely internal
implementation detail.

Let me put it this way: a Python expression like 3/x-1 may be parsed into a
abstract syntax tree which might look something like this:

(OPERATOR, -, 
  (OPERATOR, /, 
    (CONSTANT, 3, None, None), 
    (NAME, 'x', None, None)), 
  (CONSTANT, 1, None, None)
  )


Should we say that the / and - operators therefore create tuples? I don't
think so.



-- 
Steven