[Python-ideas] Re: Is possible some day add Uniform Function Call Syntax (UFCS) in Python like Dlang?

On Sun, Jun 28, 2020 at 02:23:38PM -0000, marcone@email.com wrote:

That converts calls like:

a.fun()

to

fun(a)

I don't think that will be a good match for Python. In D, the compiler can decide at compile time:

• the instance a has no fun method;
• there is a global function fun;
• which takes a single parameter that matches the type of a;

and so convert the method call to a function call at compile time, with no loss of efficiency or safety.

But in Python, none of that information is available until runtime:

• the compiler doesn't know what type a will have;
• whether or not it has a fun method;
• whether or not there is a global function fun;
• and whether it takes an argument matching a.

So all of that would have to happen at run time. That means that using UFCS would make slow code. The interpreter would have to try calling a.fun(), and if that failed with an AttributeError, it would then try fun(a) instead.

-- Steven