Provide a way to reference current class for intstance methods

[dluciv]

Imagine following:

class MyDummyNumber:
    ...
    @dispatch(int)
    def __add__(self, i):
        ...

    @dispatch(MyDummyNumber)
    def __add__(self, m):
        ...

As expected, we have NameError: name 'MyDummyNumber' is not defined here, which is not multipledispatch issue, but Python one.

There are many ugly ways to workaround this. Then beautiful way is needed!

However multipledispatch works during runtime, so I think that it is potentially possible to specify "current class" during dispatching definition, like following:

    @dispatch(multipledispatch.current_class)
    def __add__(self, m):
        ...

[francesco-ballarin]

This is supported in my patched version at #78 through lambda functions. No agreement has been reached on possible integration. Have a look if that could be helpful.

[dluciv]

A great way as for me, waiting to get it in new releases. Thank you!

May be it is even useful to define identical function inside multidispatch module, as Python lacks built-in one.

[Mystic-Mirage]

I've tried to solve this in my PR #100

[lucag]

Just ran into the same problem. Any progress on this?

@Mystic-Mirage's PR seems to be consistent with annotations currently in use, which employ stringified type names when a forward declaration is needed. So in the case of @dluciv's example, one would simply write

class MyDummyNumber:
    ...
    @dispatch(int)
    def __add__(self, i):
        ...

    @dispatch('MyDummyNumber')
    def __add__(self, m):
        ...

Another possible solution would be to use the Self type introduced by PEP 673, but that also does not work with the current implementation of multipledispatch.

[Mystic-Mirage]

There is another way to fix this by adding support for from __future__ import annotations introduced in PEP 563

Currently, it breaks multipledispatch completely but looks promising.