Re: Opinions wanted: deprecate mglyph from MathML 4 (full) spec?

Hi Neil, all,

To my reading, this is an obvious situation for MathML Core, which has the
Web Platform available at all times.

For MathML Full, it would be nice to have more transparency about which
non-web use cases MathML 4 is trying to enable. Are they in circumstances
such as JATS+MathML and PDF+MathML, where CSS and <img> tags are not
available?

JATS may be a good example. If I recall this is the classic challenge: if
an external XML vocabulary decides to fully *delegate* math syntax to
MathML, then MathML itself needs to provide the *entire* tag suite to
capture the necessary scope of representation. In consequence, this leads
to a necessary conflict with "mixed" context uses, such as HTML+MathML,
where tags are allowed to intermingle.

JATS also has a similar vehicle to <mglyph> which they could reach
for, called <private-char>:
https://jats.nlm.nih.gov/archiving/tag-library/1.3/element/private-char.html

LaTeXML is not currently emitting <mglyph>, but I am quite certain custom
glyphs are used in arXiv and emitted as images in today's HTML. For a
dramatic example, one can examine Sections 4 and 5 of hep-th/0508154:

https://ar5iv.labs.arxiv.org/html/hep-th/0508154#S4.Ex15

So I would claim the need for representing these custom glyph constructs is
real, if rare. I wonder if asking the JATS group for an opinion on <mglyph>
would be a constructive attempt at outreach.

Greetings,
Deyan

On Wed, Sep 4, 2024 at 3:40 PM Neil Soiffer <soiffer@alum.mit.edu> wrote:

> At the last Math WG meeting, there was some discussion of potentially
> deprecating <mglyph/> from MathML full. It is not part of core. For
> browser-based implementations, embedding <img/> inside of a leaf element is
> an alternative to <mglpyh>.
>
> According to this MDN page
> <https://devdoc.net/web/developer.mozilla.org/en-US/docs/Web/MathML/Element/mglyph.html>,
> <mglpyh> is not implemented in any browser. I wrote a codepen
> <https://codepen.io/nms/pen/GRbwxzR> and verified this is true for Chrome
> and Firefox.
>
> If you oppose deprecating <mglpyh>, please reply and state your reasons
> for continuing to keep it in the MathML 4 spec.
>
>