fixed the rock-paper-scissors docs example

[alexhroom]

Fixes a mistake in the doc page added by #1413 - it turns out that strategies can recognise actions from different games corresponding to the same row/column, so long as both of the Action classes have a total ordering. That is:

Using the example code from before this PR:
axl.rockpaperscissors.RPSAction.P == axl.Action.D -> False
After this PR:
axl.rockpaperscissors.RPSAction.P == axl.Action.D -> True

This is good news for the interoperability of different games! :)

[drvinceknight]

Not actually sure what's causing the sphinx failure on read the docs. Here's the stack trace:

raceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/axelrod/envs/1419/lib/python3.7/site-packages/sphinx/registry.py", line 472, in load_extension
    mod = __import__(extname, None, None, ['setup'])
  File "/home/docs/checkouts/readthedocs.org/user_builds/axelrod/envs/1419/lib/python3.7/site-packages/sphinx/builders/linkcheck.py", line 19, in <module>
    from requests.exceptions import HTTPError
  File "/home/docs/checkouts/readthedocs.org/user_builds/axelrod/envs/1419/lib/python3.7/site-packages/requests/__init__.py", line 43, in <module>
    import urllib3
  File "/home/docs/checkouts/readthedocs.org/user_builds/axelrod/envs/1419/lib/python3.7/site-packages/urllib3/__init__.py", line 39, in <module>
    "urllib3 v2.0 only supports OpenSSL 1.1.1+, currently "
ImportError: urllib3 v2.0 only supports OpenSSL 1.1.1+, currently the 'ssl' module is compiled with OpenSSL 1.0.2n  7 Dec 2017. See: https://github.com/urllib3/urllib3/issues/2168

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/axelrod/envs/1419/lib/python3.7/site-packages/sphinx/cmd/build.py", line 303, in build_main
    args.tags, args.verbosity, args.jobs, args.keep_going)
  File "/home/docs/checkouts/readthedocs.org/user_builds/axelrod/envs/1419/lib/python3.7/site-packages/sphinx/application.py", line 224, in __init__
    self.setup_extension(extension)
  File "/home/docs/checkouts/readthedocs.org/user_builds/axelrod/envs/1419/lib/python3.7/site-packages/sphinx/application.py", line 449, in setup_extension
    self.registry.load_extension(self, extname)
  File "/home/docs/checkouts/readthedocs.org/user_builds/axelrod/envs/1419/lib/python3.7/site-packages/sphinx/registry.py", line 475, in load_extension
    raise ExtensionError(__('Could not import extension %s') % extname, err)
sphinx.errors.ExtensionError: Could not import extension sphinx.builders.linkcheck (exception: urllib3 v2.0 only supports OpenSSL 1.1.1+, currently the 'ssl' module is compiled with OpenSSL 1.0.2n  7 Dec 2017. See: https://github.com/urllib3/urllib3/issues/2168)

Extension error:
Could not import extension sphinx.builders.linkcheck (exception: urllib3 v2.0 only supports OpenSSL 1.

I believe this is fixed here: readthedocs/readthedocs.org#10290. Will open a PR (hopefully) a fix to your branch @alexhroom.

[drvinceknight]

I've opened alexhroom#1

[alexhroom]

@drvinceknight looks like it's working - i also had to add numpy to the doc requirements.txt since it isn't being mocked.

[marcharper]

axl.rockpaperscissors.RPSAction.P == axl.Action.D -> True

I'm still not convinced we want this to be true -- it feels like a type mismatch. axl.action.D could reasonably equal RPSAction.S as well (being the last play rather than the second play). We're forcing a specific permutation of the actions for not a lot of benefit IMO.

Regardless of the mapping chosen, a 2x2 player like TFT may be able to technically play a game of higher dimension, but only in a degenerate way (restricted to a subset of actions). I don't see that this is really useful, other than perhaps refactoring some of the (degenerate) pure strategies like Cooperator and Defector to be more generic.

[alexhroom]

@marcharper it matters a lot less now we've got a better idea on how we're going to redesign/refactor strategies - i'll leave this for now and create a separate PR just with the RTD fix.