UCD checking from ivoatex

[Mark Taylor]

Markus et al.,

I've added tests for validity of UCDs in the LaTeX source to the 
EPNTAP document build.  This is currently on branch testucd at 
https://github.com/mbtaylor/EPNTAP, so e.g. you can see the commits at
https://github.com/ivoa-std/EPNTAP/compare/master...mbtaylor:testucd

This adds a Makefile test target invoking a script check-ucds.sh,
which extracts the arguments of \ucd macros in the document source
into a text file and then runs a suitable (Ucidy-powered) STILTS 
command on it that fails in the event that any of the words is not 
a valid UCD.  You could do something similar for VOUnits where
applicable.

I already caught a brace of bad UCDs with it
(https://github.com/ivoa-std/EPNTAP/commit/cf9f18ef16)
which surprised me since I thought I'd been through the document
carefully by eye.

Do you think something like this should get written up in ivoatexDoc?  
The UCD extraction (lots of sed/grep magic - is there a better way?) 
is rather fragile and hacky which makes me reluctant to hold it up 
as an example in the ivoatexDoc text.  But we could outline the idea
and point to EPNTAP as somewhere this is done.
Or maybe this is getting a bit too specific for what ivoatexDoc is
supposed to be documenting.  What do you think?

Mark

--
Mark Taylor  Astronomical Programmer  Physics, Bristol University, UK
m.b.taylor at bristol.ac.uk          http://www.star.bristol.ac.uk/~mbt/