On Mar 19, 2016, at 18:18, Guido van Rossum guido@python.org wrote:
Second, https://github.com/python/typing/issues/186. This builds on the previous syntax but deals with the other annoyance of long argument lists, this time in case you *do* care about the types. The proposal is to allow writing the arguments one per line with a type comment on each line. This has been implemented in PyCharm but not yet in mypy. Example:
def gcd( a, # type: int b, # type: int ): # type: (...) -> int <code here>
This is a lot nicer than what you were originally discussing (at #1101? I forget...). Even more so given how trivial it will be to mechanically convert these to annotations if/when you switch an app to pure Python 3.
But one thing: in the PEP and the docs, I think it would be better to pick an example with longer parameter names. This example shows that even in the worst case it isn't that bad, but a better example would show that in the typical case it's actually pretty nice. (Also, I don't see why you wouldn't just use the "old" comment form for this example, since it all fits on one line and isn't at all confusing.)