Uniform Function Call Syntax (UFCS)

[jongiddy]

On Sunday, 8 June 2014 15:59:14 UTC+1, Roy Smith  wrote:
 
> Why?  I assume a language which promoted the global namespace to be in 
> the attribute search path (which, as far as I can tell, is what we're 
> talking about here) would implement hasattr and raising AttributeError 
> in a consistent way.

It's slightly different. Although I used len() as an example, the idea is to allow any function to be used in this way, including local symbols.

e.g. I could define:

def squared(x):
    return x * x

i = 3
i.squared() => 9

j = AClassThatImplements__mul__()
j.squared() => whatever j * j returns

but also:
class AnotherClass:
    def __mul__(self, other):
        ...
    def squared(self):
        return specialised_method_for_calculating_squares()

k = AnotherClass()
k.squared() => calls method, not function

In this case, there is a problem with letting hasattr('squared') return True for these first two instances.  See Ian's post for a description of the problem.