Re: [bug #46083] DeclareUnicodeCharacter breaks if used twice for same character

[Karl Berry]

    come up with for a tick was the radical sign.

The lineless radical looks surprisingly ok to my eyes.  I hadn't thought
of that.  Sounds fine.  The complication is that we're not currently
loading cmex at different sizes at all, so that will take some tweaking
a la cmmi to do it right.  Although just always using the 10pt size
doesn't seem like the end of the world either :).

    It depends on what glyphs are available in the fonts.

There are lots of check marks in lots of fonts, including the ubiquitious
Zapf Dingbat ... but not in any font we are currently loading, and
adding another (just for this) does not seem worth it to me.

The document at http://ctan.org/pkg/comprehensive (or, hopefully,
"texdoc comprehensive" from the command line) is the most thorough
reference to finding availabilty of symbols I know of.  Of course it's
about LaTeX rather than plain TeX, so the actual \commands won't work,
but at least it's possible to then find the fonts, print the font table
to find the character, etc.

Best,
Karl