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

Y.D.X · April 8, 2025, 1:14pm

#set page(height: auto, width: 10em, margin: 1em)
Then $exists x > 0, f(x) = y$ and why?

How to allow the line to break after ,? I think the following would be better.

Then ∃x>0,
f(x) = y and
why?

Why can’t I split it?

$exists x > 0$, $f(x) = y$

My document is not English, and I have to use a dedicated font for my main text. The font provides a good glyph for this comma, but it does not fit well among Latin-like characters in math equations.

Moreover, I can’t set text(font: (covers: regex_matching_comma_period_etc, …)), because it will destroy kerning.

My (failed) attempts

Adding med/thin/etc. doesn’t break the line.
Inserting zwj/zwnj changes nothing.
Inserting a #linebreak() gives a weird result.

janekfleper · April 8, 2025, 1:46pm

You could just wrap the comma in a separate equation to get the correct font. The space of the comma relative to the zero looks to be equal to the case where everything is in the same equation. The space behind the comma will be wider by default because you have to use the “plain-text” space between the last two equations. This is however not an issue when you have a line break.

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

Y.D.X · April 8, 2025, 2:11pm

Thank you! Inspired by your reply, I realize that I can simply write:

$exists x > 0,$ $f(x) = y$

But to be honest, I don’t think this is an elegant way…

Andrew · April 8, 2025, 3:45pm

Indeed, this is how you would split it.

Well, long inline math is hard to make look good. Typst is a WYSIWYM tool, so if you explicitly don’t say it to break, it won’t break. If you want, you can always open a new issue and see if others will agree. Perhaps this can be improved.

Y.D.X · April 8, 2025, 4:12pm

WYSIWYM

But it breaks between> and 0!

I will create an issue when I have time, unless someone does it first.

Andrew · April 8, 2025, 4:16pm

True. I guess changing the breaking locations and their priority would be nice to have.

Eric · April 8, 2025, 4:35pm

A related issue regarding customizable line breaking behaviour in math already exists:

github.com/typst/typst

Simple way to add non-breaking space in math mode

opened 02:50PM - 20 Aug 24 UTC

memeplex

feature request math syntax

### Description Inline equations may be particularly sensible to arbitrary li…ne breaks. A convenient way to add non-breaking space (such as `~` in text mode) would be helpful. One can also box the equation, although that currently introduces some baseline related issues e.g. (see also https://github.com/typst/typst/issues/4796): ```typst Hello #box($a + sum_(i=1)^n x_i / y_i$) world ``` <img width="227" alt="image" src="https://github.com/user-attachments/assets/f78339e9-ea22-40fe-933e-26ff3fc8ae49"> Maybe fixing this would be enough, but I believe that `~` or similar could help. ### Use Case During the final phase of document edition it would be useful to add a handful of `~` where the author detects problematic line breaks inside equations.

Y.D.X · April 9, 2025, 3:54am

I’ve just found an exact issue:

github.com/typst/typst

In inline math mode, allow breaking lines after a comma

opened 05:33PM - 28 Oct 24 UTC

jmigual

feature request math

### Description There are already some cases where inline math breaks lines aut…omatically. However, it seems that comma doesn't trigger this scenario. It'd be nice to either: (1) have an option to choose whether or not a line break can be added after a comma or (2) make commas "breakable" by default. ### Use Case In my use case, I was trying to write a very long tuple: ```typst Test of a sentence with math that should break after a comma: $E = (M, O, sans("cap"), sans("prc"), sans("nextM"), sans("csiM"), sans("csd"))$ ``` And this is how it rendered: ![image](https://github.com/user-attachments/assets/62faef9d-f6ef-461f-8394-e357eeef6a34) The Typst version used for this is v0.12.0.

Therefore, I will close this topic. Hope the linebreak algorithm will be improved someday.

Y.D.X · November 4, 2025, 1:11am

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.)