Is there a way to redefine \int to \int\limits globally?

[pedrolimasi]

Setting global macros is easy enough, but macros requires 2 things for a substitution. What can we do for something done with \let?

As a simple example:

\let\Oldint=\int
\def\int{\Oldint\limits}

This works isolated equation-by-equation, but I'd like to set it globally.
The second line has a macro syntax, but not the first.

There's an open issue (#2915) that is somewhat related but not quite the same.

[edemaine]

You could run the macro code with globalGroup: true and pass in a macros object, then provide that macros object to all future calls. If you're not familiar with the API (e.g. you're just using auto-render), I can provide more explicit code.

[pedrolimasi]

Perhaps a sub-question may be the key here:

How should I add \Oldint as a macro in the macros object?

• "\\let\\Oldint": "\\int" doesn't work, and
• "\\Oldint": "\\int" creates an infinite loop when I redefine \int

[edemaine]

Apologies; I thought this was possible, but it turns out it's not. I just tried katex.renderToString(`\let\Oldint=\int`, {macros, globalGroup: true}) with the goal of looking at what macros object gets produced, but it turns out that this doesn't populate the macros object at all.

[edemaine]

Sorry, I made a mistake. Instead I did this:

katex.renderToString("\\let\\Oldint=\\int", {macros, globalGroup: true}) 

Now macros gets populated as roughly {"\\Oldint": {tokens: [{text: "\\int", noexpand: true}], unexpandable: false, numArgs: 0}}.

I would therefore expect macros: {"\\Oldint": {tokens: [{text: "\\int", noexpand: true}], unexpandable: false, numArgs: 0}, "\\int": "\\Oldint\\limits"} to work... but currently it seems to produce an infinite loop. Hmm.

[pedrolimasi]

Is this enough to open an issue? Since I'm running KaTeX through the VSCode extension Markdown Preview Enhanced, I'd expect a bug report from my use-case description would be... bad.

[edemaine]

Yep. Just opened #3737. Thanks!

[pedrolimasi]

[WORKAROUND]

Use \intop instead of \int\limits.

In the macros object, that would be:
"\\int": "\\intop"