Physics package bindings do not work for MathJax3

[eeopd]

Hi all, I'm having troubles with the physics latex package that is included in MathJax 3.

To reproduce, just run

jupyter labextension install @jupyterlab/mathjax3-extension
jupyter labextension disable @jupyterlab/mathjax2-extension

Then create a notebook, try to execute a markdown cell with a physics command in it, e.g.
$$ \dv{y}{x} $$
This makes the command red, indicating some sort of error.

Secondly, importing the physics package explicitly does not work either: $$\require{physics}$$ gives a red error too, but this should not be necessary as this extension seems to be configured to load all extensions anyway. The physics commands do work on the live demo on the MathJax site (after importing the package).

Do you have any idea where the problems lies? Or where I could look to fix it or get more debugging information?

[jasongrout]

I just checked, and indeed the \require command doesn't seem to work. I'm not sure exactly why, but perhaps has to do with us loading the tex extension manually instead of doing something with the loading system of mathjax?

The AllPackages thing we import seems to be this, which does not include require or physics: https://github.com/mathjax/MathJax-src/blob/6ba6cca458080ec2a73c60f8b19db6491985f92b/ts/input/tex/AllPackages.ts#L78

Before I ran out of time looking at this, I tried editing AllPackages to include 'require', but that didn't seem to make \require available.

[jlrpnbbngtn]

I was able to get physics to work by cloning MathJax-src and adding physics to AllPackages within that project. And then updating the dependencies in the package.json to point at the local directory. I haven't tried adding require yet.

[randolf-scholz]

According to mathjax/MathJax-src#553:

the physics package redefines lots of standard macros (like \sin, \cos, etc.), and so is not included in the AllPackages variable, since that is frequently used to turn on all the extensions.

But it is added in the MathJax.loader.preLoad.

[pordyna]

I was able to enable physics by changing

jupyter-renderers/packages/mathjax3-extension/src/index.ts

Line 43 in 19b5ff1

packages: AllPackages,

to packages: AllPackages.concat('physics') and rebuilding as described in your readme, But this is more of a hack. It would be great to have a support for a mathjax user config so that one could do

window.MathJax = {
  loader: {load: ['[tex]/physics']},
  tex: {packages: {'[+]': ['physics']}}
};

like described in mathjax documentation
Alternatively maybe just internally add require to loader and packages so that $$\require{physics}$$ would work.

Unfortunately, I know nothing about TypeScript and I can't do it myself. This is just as a friendly user request.

[bsdz]

I created a PR (#282) to add support for the requires extension. Now we can selectively load the physics package when needed.