Possibly of interest for our interchange formats, especially the
text-based one.

http://people.csail.mit.edu/jaffer/MIXF/

Metric Interchange Formats describe character string encodings for
numerical values and units which:

- are unambiguous in all locales;
- use only Portable Character Set [PCS] characters which are also Basic
Latin characters in Plane 0 of the Universal Character Set [UCS];
- are transparent to [UTF-7] and [UTF-8] UCS transformation formats;
- are human readable and writable;
- are machine readable and writable;
- incorporate SI prefixes and units;
- incorporate [ISO 6093] numbers; and
- incorporate [IEC 60027-2] binary prefixes.

Additionally, CMIXF incorporates [ISO 4217] currency names.

 From Aubrey Jaffer, author of the SLIB library as well as the classic
Scheme implementation SCM.