Intent to prototype: text-transform: math-auto

[Frédéric Wang]

Summary: A common style convention is to render identifiers with
multiple letters (e.g. the function name "exp") with normal style and
identifiers with a single letter (e.g. the variable "n") with italic
style. The math-auto property is intended to implement this default
behavior, which can be overridden by authors if necessary. Note that
mathematical fonts are designed with a special kind of italic glyphs
located at reserved Unicode positions, so using text-transform for that
purpose makes sense.

Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1821980

Specification: https://w3c.github.io/mathml-core/#new-text-transform-values
Standards Body: MathML Core, CSS WG (see
https://github.com/w3c/csswg-drafts/issues/5386 )

Platform coverage: All
Preference: mathml.legacy_mathvariant_attribute.disabled

DevTools bug: N/A
Link to standards-positions discussion: N/A
Other browsers:

    Blink: Shipped since version 109
    WebKit: Considering (https://bugs.webkit.org/show_bug.cgi?id=202302)

web-platform-tests:
https://wpt.fyi/results/css/css-text/text-transform/math?label=master&label=experimental&aligned&q=math%20%20not%28path%3A%2Fjs%29

One of the common use case is to implement MathML automatic italic
mathvariant for single-char <mi> elements:
https://w3c.github.io/mathml-core/#the-mathvariant-attribute ; I'll send
a separate email for intenting to unship mathvariant other than <mi
mathvariant=normal>.

--
Frédéric Wang