Hello all, Thanks everyone for comments on our earlier thread [1] about callable type syntax. We now have a draft PEP [2] proposing an arrow-based syntax for callable types, for example: ``` (int, str) -> bool # equivalent to Callable[[int, str], bool] ``` In support of the PEP we also have: - a reference implementation of the parser [3] to ensure the grammar is correct (tests [5], [6], [7]) - a detailed specification of planned runtime behavior [4], which is not yet in the reference implementation We'd like to get your feedback about the PEP in general, and especially details and edge cases we need to consider regarding runtime behavior. Cheers, Steven Troxler --------- [1] Earlier python-dev thread https://mail.python.org/archives/list/python-dev@python.org/thread/VBHJOS3LO... [2] PEP 677: https://www.python.org/dev/peps/pep-0677/ [3] Reference implementation of Parser: https://github.com/stroxler/cpython/tree/callable-type-syntax--shorthand [4] Details on the runtime behavior: https://docs.google.com/document/d/15nmTDA_39Lo-EULQQwdwYx_Q1IYX4dD5WPnHbFG7... [5] Ast tests for parser changes: https://github.com/stroxler/cpython/blob/20eb59fdca0d6d8dbe4efa3b04038c7c220... [6] Easy-read tests of examples from the PEP: https://github.com/stroxler/cpython/blob/callable-type-syntax--shorthand/Lib... [7] Test sanity checking hundreds of examples pulled from typeshed: https://github.com/stroxler/cpython/blob/callable-type-syntax--shorthand/Lib...