LSR integration with lilypond docs

[Graham Percival]

For a while I've been musing on how to make LSR more visible/useful,
and now I have some time to play with it.

There are two problems I'd like to solve:
- there are too many collections of lilypond code floating around.
(input/test/, input/regression/, LSR, mailist archives)   As a result,
many users don't look at any of them.  If we had a single place for
examples, we could direct users there, much more prominently.
- some users say that they want somewhere to post longer lilypond
examples.

My proposed solution is as follows:
- we replace the current "examples" section of the official docs
(there's about half a dozen pieces there) with a page that lists
categories of examples: short complete works (the current examples),
tricks and tips (the current input/test/), long teaching examples (new
material from users), LSR (the whole thing), etc.
- we get all these examples from LSR.  When users add an example, they
can give it a tag that marks it to be included in one (or possibly
more) of those categories.  This is reviewed by somebody (probably me,
although it would be nice to have somebody else do this).  The next
time the doc people update the lilypond examples (this _is_ me :), we
can download the categorized examples from LSR.


*** this is only necessary if we want to do automate the process;
*** see below.
The following changes to LSR would be necessary:
- each snippet gets an extra field, called "tag" or "category" or
"genre" or something like that.  This field will contain a value (or
possibly more than one -- right now I think we only want single values)
such as "short examples", "advanced tricks", etc.
- marking a snippet with this tag is only temporary; the snippet must
be reviewed by an editor before the tag can be official.
- some user account(s) will need to be marked as "editor"s; this may
require changes to the way LSR handles users.  (I don't know enough
about that side of LSR to judge)
- in addition to the "download LSR" option, it would be nice to have
a "download categories" options -- ie only download snippets which are
marked to be in a special category, and to have these sorted.  ie we
get a tarball containing
short/twinkle.ly
short/blah-blah.ly
advanced/scheme-display-time.ly
tricks/ossia.ly

I can then copy these files to input/  and upload to CVS.
input/regression/ would _not_ be covered by this.  Any regression test
which contains neat tricks would be added to LSR as a trick, but after
that has been done, we'll ignore input/regression/ completely (that's
the developer's playground).


*** non-automated solution
If these changes to LSR would be awkward to do, we could do all the
sorting locally -- we can maintain a list of which example goes where,
and simply download the entire LSR every so often to update things.  In
fact, to be honest the only reason I can think of to modify LSR is just
to make users feel more important.  ("I added something to LSR and
marked it as a `teaching tool'", instead of "I added something to LSR
and send an email to -devel asking it to be included as a "teaching
tool").


Thoughts?
- Graham