seequent / methoddispatch Goto Github PK

a singledispatch decorated function has public registry and dispatch attributes. These are not present on the bound and unbound methods returned by Class.foo or instance.foo.

Per-subclass registries are nice, but an even nicer addition would be per-instance registries, e.g.

class C(SingleDispatch):
    @singledispatch
    def foo(self, bar): ...

c = C()
register(c.foo, some_type, some_function)

As an example use case, in mplcursors (https://mplcursors.readthedocs.io/en/stable/), I use functools.singledispatch to generate "cursor" implementation for various Matplotlib artist classes, but an end user cannot override the way a specific class is picked without modifying the global singledispatch object. Having per-instance registries would, well, allow such a per-instance override.

Python 3.7 has added an support for reading the override type from the function annotation.
We should support this too on python 3.7.

as per https://bugs.python.org/issue40464

You can't navigate from a string to the method you are dispatching.

permit:

class SubClass(BaseClass):
   @register(BaseClass.foo, int)
   def foo_int(self, bar):
      ...

This is because the name is mangled in the attributes dictionary, but not elsewhere.

your setup.py says "BSD", please include a license file with actual license text.