[XeTeX] Roman Numerals as stylistic alternatives

[mskala at ansuz.sooke.bc.ca]

On Sun, 19 Jun 2011, Tobias Schoel wrote:
> if I understand correctly, that way the output still shows the letters or the
> deprecated unicode codepoints. It should be analog to medieval / lowercase
> numbers. E.g. it's still the number 123 it only uses different glyphs. So when
> I copypaste it, it shows the number 123 and not cxxiii.

I think the only plausible way for that to happen would be for it to be a
feature of the font, specifically a type of ligature substitution that
replaces the numeral glyphs with appropriate other glyphs while naming
them such that reader software can determine the original sequence of code
points.  If it's built into the font as an OpenType feature, then you
could turn it on with fontspec.  But it would be a feature of the font,
not a feature of fontspec; wanting fontspec to do it in a font that
doesn't have such a feature built in would make about as much sense as
wanting a fontspec feature to enable Tamil script in a font that only
contains Latin glyphs.
-- 
Matthew Skala
mskala at ansuz.sooke.bc.ca                 People before principles.
http://ansuz.sooke.bc.ca/