in-place exponentiation incongruities

[Steven D'Aprano]

On Sat, 11 Aug 2012 09:54:56 -0700, Giacomo Alzetta wrote:

> I've noticed some incongruities regarding in-place exponentiation.
> 
> On the C side nb_inplace_power is a ternary function, like nb_power (see
> here:
> http://docs.python.org/c-api/typeobj.html?
highlight=numbermethods#PyNumberMethods).
> 
> Obviously you can't pass the third argument using the usual in-place
> syntax "**=". Nevertheless I'd expect to be able to provide the third
> argument using operator.ipow. But the operator module accept only the
> two parameter variant.

Why? The operator module implements the ** operator, not the pow() 
function. If you want the pow() function, you can just use it directly, 
no need to use operator.pow or operator.ipow.

Since ** is a binary operator, it can only accept two arguments.


> The Number Protocol specify that the ipow operation ""is the equivalent
> of the Python statement o1 **= o2 when o3 is Py_None, or an in-place
> variant of pow(o1, o2, o3) otherwise.""

Where is that from?


-- 
Steven