supporting named arguments about multimethod HOT 2 CLOSED

I think any linear scan of the registered functions is off the table, because it's so slow and overload already does that. There is the possibility of using inspect.Signature.bind once to get the positional arguments for use in dispatch. That would require having a definitive signature, and would still be slower. In my testing with a single argument it would be about 5x slower than the current implementation, which is on par with functools.singledispatch.

Which reminds me of discussion #12, because another oddity about singledispatch is that it effectively requires a base implementation with no annotations (which is to say it ignores them). That could be an elegant way for a user to indicate that they're willing to take the performance hit, by providing the definitive signature needed anyway.

So it would look like:

@multimethod
def f(foo):
    pass

@multimethod
def f(foo: str):
    return foo

f(foo="bar")

from multimethod.

Another concern is that singledispatch requires positional arguments.

from multimethod.