Patching a math command using regexpatch

Asked Jun 13 '22 at 17:00

Active Jun 13 '22 at 17:00

Viewed 44 times

I want to allow my inline math to break lines after \sim, which I'm using a lot. To this end, I've tried:

\usepackage{regexpatch}
...
\xapptocmd{\sim}{\allowbreak}{SUCCESS}{FAIL}
...
$X \sim N(0, 1)$

Unfortunately this just prints out FAIL at the top of the document, but I'm not sure how to diagnose why \xapptocmd is actually failing. Is it possible to patch math commands in this way?

I'm happy to swap regexpatch out with any other package if it helps.

asked Jun 13 '22 at 17:00

Migwell

2

The reason involves quite some low-level TeX details... but there's \let\oldsim\sim \def\sim{\oldsim \allowbreak} – user202729 Jun 13 '22 at 17:04
\sim is not a command, it is a \mathchar. – Ulrike Fischer Jun 13 '22 at 17:04
3

\sim is not defined with \def or similar instruction, so it cannot be patched this way. By the way, line breaks are allowed after relation symbols, which \sim is. – egreg Jun 13 '22 at 17:04
1

Please add value to your question by adding relevant code, starting with documentclass (copy&run). – MS-SPO Jun 13 '22 at 17:04
Probably duplicate of math mode - automatic \allowbreak around mathbin and mathrel characters - TeX - LaTeX Stack Exchange. (or not? Not sure) – user202729 Jun 13 '22 at 17:05
1

beside this: breaking after \sim is already allowed, it works fine for me. – Ulrike Fischer Jun 13 '22 at 17:08
For inline math I don't think anything breaks automatically? – Migwell Jun 13 '22 at 17:09
1

@Migwell No line break is possible if you use \sim inside \left-\right pairs, for instance. But generally a break after \sim is allowed. – egreg Jun 13 '22 at 17:20
Right, well then I need to diagnose why my document is not breaking at anything. – Migwell Jun 13 '22 at 17:21
Okay it turns out I wasn't getting any equation breaking due to: https://tex.stackexchange.com/a/362034/169711. Happy to close or post this as an answer as appropriate. – Migwell Jun 13 '22 at 17:35

Patching a math command using regexpatch

0 Answers0