How to control line breaks (wrap opportunities) in inline math?

[Y.D.X]

N. V. Lang provided an allowbreak on 2025-07-21. It’s more elegant and easier to type (although contains more characters).

#set page(height: auto, width: 10em, margin: 1em)

#let allowbreak = math.script(math.class("binary", ""))

Then $exists x > 0, allowbreak f(x) = y$ and why?

Unfortunately, this solution doesn’t work well in all cases (for example, it breaks the spacing in $a allowbreak + b$). But I personally found it sufficient as a temporary workaround for the commas use case.

(I tried making all commas in math mode automatically insert such an allowbreak after themselves with #show math.comma: math.comma + allowbreak, but this seemed to break kerning around commas both inside and outside of math mode.)