From J.Demeyer at UGent.be  Fri Jun  1 13:56:47 2018
From: J.Demeyer at UGent.be (Jeroen Demeyer)
Date: Fri, 1 Jun 2018 19:56:47 +0200
Subject: [Cython] Should we start requiring "language_level=2" for .pyx
 files?
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 <47b0cae337ba4e489d9a40d9accd1795@xmail101.UGent.be>
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On 2018-05-31 16:35, Erik Bray wrote:
> Perhaps you could clarify something:  I tried suggesting a while ago
> that Sage start using language_level=3 at least when actually building
> Sage on Python 3.  I know this isn't necessary but it just seemed to
> make logical sense.  But Jeroen was convinced it wasn't necessary
> because, according to him, language_level=3 doesn't really do
> anything.

For the record, the thing that I objected most to was changing it *only* 
on Python 3. For best portability, you should use either 
language_level=2 or language_level=3 (as opposed to making the 
language_level depend on the Python version that you are targetting).

language_level=3 enables all __future__ imports for Python 3 (like 
unicode_literals) and it changes the parser to be like Python 3 (this 
impacts exec for example). So it does affect stuff, but not so much 
beyond what you can get with __future__ imports.