[h5md-user] Finalization of units module

[Peter Colberg]

Hi all,

Since there is considerable interest in publishing a finalized version
of the units module along with the first release of H5MD, I familiarized
with the udunits2 library, and tested the specification of the units
module.

Please see the test results in examples/h5md.lua of Lua Units [1]:

http://git.colberg.org/lua-units/

The grammar is fine, i.e. it is a subset of the udunits2 grammar.

There are a number of symbols that do not match a unit in the udunits2
database. There is one symbol ("h") that corresponds to a different
unit than in the udunits2 database ("hour").

Some issues can be resolved by using the name of the unit (e.g.
"degree" instead of "deg"). Other issues can not be resolved due to
not having a corresponding unit in the udunits2 database. I suggest to
drop the latter units, since it is possible but painful to maintain a
custom database for the H5MD units module.

Peter

[1] http://colberg.org/lua-units/