[Python-ideas] PEP 484 (Type Hints) -- first draft round

[Andrew Barnert]

On Jan 22, 2015, at 12:05, Guido van Rossum <guido at python.org> wrote:

> But this is an area where we may be able to cater to different preferences by passing the type checker different flags or configurations. So I don't want to make a big thing out of this, and if people think it's useful, this can well be an option.

I agree with everything else you said, but I'm not sure I understand this paragraph. The PEP isn't specifying anything about type checkers except how they interpret type annotations. So isn't such a flag just a quality of implementation issue on (hopefully-competing) checkers and IDEs and other tools?

Are you just suggesting that such a flag can be added to MyPy (which will likely encourage other checkers to do the same unless nobody finds it useful)? Or are you planning to expand the spec with suggestions for configuration that type checking tools should consider offering?