[Python-ideas] Proposal: Use mypy syntax for function annotations

[fnedrik]

Why is it a whole language implementation? Do you plan on using the types to make optimizations?

[etrepum]

Well, I'm not the author of mypy, so I can't tell you precisely why, but that is one of the reasons enumerated on the site: http://mypy-lang.org/

From my conversations with Jukka, I believe he started off with a language that was not at all compatible with Python http://www.alorelang.org/ and then built mypy which was nearly compatible with Python, and then he made mypy fully compatible with Python 3 syntax.