[Python-Dev] can't assign to function call (original) (raw)

Hrvoje Niksic hrvoje.niksic at avl.com
Mon Mar 18 17:36:17 CET 2013

On 03/18/2013 04:40 PM, Steven D'Aprano wrote:

In analogy with that, Python could implement what looks like assignment to function call like this:

val = f(arg) # val = f.call(arg) f(arg) = val # f.setcall(arg, val) That's all very well, but what would it do? It's not enough to say that the syntax could exist, we also need to have semantics.

I am not the best person to answer because I go on to argue that this syntax is not needed in Python at all (anything it can do can be implemented with setitem at no loss of clarity). Still, if such a feature existed in Python, I imagine people would use it to set the same resource that the function obtains, where such a thing is applicable.

Aside: I'd reverse the order of the arg, val in any such hypothetical setcall, so as to support functions with zero or more arguments:

f(*args, **kwargs) = val <=> f.setcall(val, *args, **kwargs)

That would be a better design, I agree.

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