[Python-ideas] Improving the expressivity of function annotations

[Paul Moore]

On 4 April 2011 11:58, Masklinn <masklinn at masklinn.net> wrote:
>> If what you are after is not (in some sense) a Pythonic version of
>> static type checking, then I apologise for misunderstanding, but could
>> you clarify?
> What I'm after is giving third-party tools the opportunity of structural typing, which is static duck typing.

OK. I understand now, thanks for the clarification.

I'm -1 on this. Static typing is not appropriate for Python, IMO.

Just as one example, note that even ABCs are not statically
deterministic. Consider ABCMeta.register and ABCMeta.__subclasshook__.
If a tool implements any form of static type checking, it will by
definition fail to handle a certain proportion of valid Python
programs. Whether this is acceptable is, of course, a personal
decision.

Paul.