[Python-Dev] PEP 484: updates to Python 2.7 signature syntax (original) (raw)

Guido van Rossum guido at python.org
Mon Mar 21 17:11:12 EDT 2016

This seemed pretty uncontroversial -- I've updated the PEP (including a long(ish) example :-).

On Sat, Mar 19, 2016 at 6:54 PM, Guido van Rossum <guido at python.org> wrote:

Heh. I could add an example with a long list of parameters with long names, but apart from showing by example what the motivation is it wouldn't really add anything, and it's more to type. :-)

On Sat, Mar 19, 2016 at 6:43 PM, Andrew Barnert <abarnert at yahoo.com> wrote: On Mar 19, 2016, at 18:18, Guido van Rossum <guido at 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 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.) -- --Guido van Rossum (python.org/~guido)

-- --Guido van Rossum (python.org/~guido)

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