Looking at PEP 484, I came up with two use cases that I felt were     not catered for:
    
          
  1. Specifying that a parameter should be a subclass of another         (example: Type[dict] would match dict or OrderedDict; plain         "Type" would equal "type" from builtins)

I don't understand. What is "Type"? Can you work this out in a full example? This code is already okay:

def foo(a: dict):
    ...

foo(OrderedDict())
 
          
  1. Specifying that a callable should take at least the specified         arguments but would not be limited to them: Callable[[str, int,         ...], Any]
    2.     
    

Case #2 works already (Callable[[str, int], Any] if the       unspecified arguments are optional, but not if they're mandatory.       Any thoughts?

For #2 we explicitly debated this and found that there aren't use cases known that are strong enough to need additional flexibility in the args of a callable. (How is the code calling the callable going to know what arguments are safe to pass?) If there really is a need we can address in a future revision.
 
-- 
--Guido van Rossum (python.org/~guido) ">

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On Sun, May 17, 2015 at 3:07 PM, Alex Grönholm <alex.gronholm@nextday.fi> wrote:
Looking at PEP 484, I came up with two use cases that I felt were not catered for:
  1. Specifying that a parameter should be a subclass of another (example: Type\[dict\] would match dict or OrderedDict; plain "Type" would equal "type" from builtins)

I don't understand. What is "Type"? Can you work this out in a full example? This code is already okay:

def foo(a: dict):
...

foo(OrderedDict())
  1. Specifying that a callable should take at least the specified arguments but would not be limited to them: Callable\[\[str, int, ...\], Any\]

Case #2 works already (Callable\[\[str, int\], Any\] if the unspecified arguments are optional, but not if they're mandatory. Any thoughts?

For #2 we explicitly debated this and found that there aren't use cases known that are strong enough to need additional flexibility in the args of a callable. (How is the code calling the callable going to know what arguments are safe to pass?) If there really is a need we can address in a future revision.
--
--Guido van Rossum (python.org/\~guido)