autogenerate the list of subdirectories of doc/en/reference

[jhpalmieri]

As the summary says. Currently, the file doc/en/reference/conf.py explicitly lists all of the subdirectories which contain components of the reference manual. If anyone adds a new component, they have to edit this file, and if they forget, they can get opaque error messages. So instead, the list should be generated on the fly.

CC: @vbraun

Component: documentation

Author: John Palmieri

Reviewer: Volker Braun

Merged: sage-5.11.beta0

Issue created by migration from https://trac.sagemath.org/ticket/14669

[jhpalmieri]

comment:1

Slightly different from the patch at #7477: I've removed 'sage', 'sagenb', 'media', and 'other' from the list of directories -- these might be present if upgrading Sage.

[vbraun]

comment:2

Looks good to me.

[vbraun]

Reviewer: Volker Braun

[nexttime]

comment:3

Minor thing: The new list isn't sorted.

[nexttime]

comment:4

Stylewise: It would be better to create a set of the subdir names and afterwards remove the "bad" ones from that (with .difference_update()).

[vbraun]

comment:5

To the best of my knowledge neither the order of the entry nor the performance of this step of the doc build matter.

[nexttime]

comment:6

Replying to @vbraun:

To the best of my knowledge neither the order of the entry nor the performance of this step of the doc build matter.

To you...

If the folders are sorted (or more precisely, get processed in alphabetical order), you at least get an idea of the progress.

W.r.t. performance: It certainly doesn't matter here (at least currently ;-) ), that's why I wrote stylewise. People^* tend to get used to such, adding overhead here and there, and at some point it does matter.

(^* which includes people reading such code, not necessarily their author(s))