Increment Pygements release to support Python 3.5 syntax

[aaugustin]

Hello,

Read the Docs offers the option to build docs with Python 2.x or 3.x, which is great.

Python 3.5 introduced some new syntax, namely the await and async keywords. Since Read the Docs runs Python 3.4, code samples that use this syntax cannot be parsed and thus aren't syntax-highlighted. See the first block on this page for example.

Have you considered making it possible to pick a specific Python version, perhaps among 2.7, 3.4, 3.5? Alternatively, do you have a rough idea of when you'll upgrade the platform to 3.5?

Thanks!

[aaugustin]

I appear to have incorrectly assumed that it was related to the version of Python running Sphinx.

Apparently the next release of Pygments (for which there's no ETA) should solve the problem.

https://bitbucket.org/birkenfeld/pygments-main/issues/1154/please-make-next-release

[agjohnson]

Regarding the Python version selection: we haven't yet, though the ability to use arbitrary versions of Python might be a good future feature.

The real issue seems to be a pending Pygments release, we'll pin the next release to come out.

[aaugustin]

Pygments 2.1 was releaseed mid-January, unblocking this issue.

[aaugustin]

Is it just a matter of bumping Pygments to 2.1.3 in requirements/pip.txt?

[agjohnson]

You'll need to update the requirements in:
https://github.com/rtfd/readthedocs.org/blob/42ab9d198494d5cf9fe320ac217d837bf480c73f/readthedocs/doc_builder/python_environments.py

[aaugustin]

I just submitted a PR with this change, I hope this helps. Thanks!