LaTeX syntax highlighting in Rmd

[gadenbuie]

• VSCode Version: 1.28.0
• VSCode-R Version: v0.6.2
• OS Version: x86_64-apple-darwin15.6.0 (64-bit)

Steps to Reproduce:

1. Use two reserved markdown characters in LaTeX math blocks in the same line
2. Syntax highlighting does not consider the LaTeX math notation and applies styling

Example of issue (with totally made up math)

Expected something more like this

TBH, simply catching the use of LaTeX and removing the syntax highlighting between paired $..$ or $$..$$ would be a great improvement.

Example text

For each $x_i$, consider all $x_i < k$.
Is $x*2$ greater than $y*2$?

$$
y_i = m * x_i + b
$$

[andycraig]

Once PR REditorSupport/vscode-R#228 is merged, I'll fix this so that text in $..$ and $$..$$ is highlighted as LaTeX (if the user has installed an extension that provides LaTeX highlighting), or has no highlighting (if they haven't installed such an extension).

[storopoli]

Guys do we have any news on LaTeX syntax highlighting?

[andycraig]

Hi @storopoli, I was planning on working on this around this time last year but it fell too far down my list of priorities.

The file that needs editing is https://github.com/Ikuyadeu/vscode-R/blob/master/syntax/Markdown%20Redcarpet.json . $$..$$ blocks will have a similar format to the fenced_blocks, and $..$ will be similar to code-inline-r. Provided the user has an extension like this installed, I think this should work for the patterns field:

"patterns" : [
    {"include" : "source.latex"}
]

[storopoli]

maybe something like this:

"inline" : {
            "patterns" : [
                {"include" : "source.latex"}
            ],
            "repository" : {
                "code-inline-latex" : {
                    "begin" : "([$|$$][ ]+)",
                    "beginCaptures" : {
                        "1" : {
                            "name" : "punctuation.definition.raw.rmarkdown"
                        }
                    },
                    "end" : "([$|$$])",
                    "endCaptures" : {
                        "1" : {
                            "name" : "punctuation.definition.raw.rmarkdown"
                        }
                    }
                }

[andycraig]

@storopoli That looks like the right sort of idea. I think it would match $$..$ and $..$$ though.

A PR for this feature would be very welcome! :)

[storopoli]

Ok, I'm new to VS Code Extensions, but I wanna help. How do I make LaTeX Workshop render stuff from .Rmd files? Can you point me towards where I can find how to do this?

I could try to implement a simple solution with just $....$ and $$...$$ math preview. Then we could analyze how to make it work with more advanced LaTeX stuff like begin{aligned|cases}...\end{aligned|cases} and \begin{matrix|bmatrix|pmatrix}...\end{matrix|bmatrix|pmatrix} etc.

[andycraig]

Great!

We use embedded languages to provide syntax highlighting for code blocks of Python, C etc. in Rmd files. It should be possible to do this for LaTeX too. The difference is that grammars for Python, C etc. are built in to VS Code itself, but LaTeX isn't built in. (The built-in languages are here: https://github.com/microsoft/vscode/tree/master/extensions)

LaTeX Workshop defines a LaTeX grammar: https://github.com/James-Yu/LaTeX-Workshop/blob/master/package.json#L172 So my (untested!) theory is that if LaTeX is added as an embedded language to the Rmd syntax file, and the user has installed LaTeX Workshop, then highlighting for begin{aligned|cases}...\end{aligned|cases} etc. should happen automatically. It might also be necessary to activate the extension by, e.g., opening a .tex file.

Here are the changes I think are necessary:

1. Modify https://github.com/Ikuyadeu/vscode-R/blob/master/syntax/Markdown%20Redcarpet.json with something like what you posted above. I think the top should be like this:

"inline" : {
            "patterns" : [
                {"include" : "#code-inline-latex"}
            ],
            "repository" : {
                "code-inline-latex" : {

Also you'll need something like this:

                    "contentName" : "meta.embedded.block.latex",
                    "patterns" : [
                        {"include" : "source.latex"}
                    ]

2. Add a new line to this section, for meta.embedded.block.latex: https://github.com/Ikuyadeu/vscode-R/blob/master/package.json#L244-L249

The command Developer: Inspect Editor Tokens and Scopes is very helpful for checking what VS Code thinks the syntax and highlighting are.

Hope that helps! We appreciate contributions so if things are still unclear or you get stuck etc. please do ask and I'll try to provide more info.

[storopoli]

I've made the changes in REditorSupport/vscode-R#553

Unfortunately I don't know how to test the extension. I've trying running with F5 but to no avail.

[andycraig]

Excellent! For testing: File menu -> 'Open Folder...' and choose select 'vscode-R' (the directory with your edits). Then press F5. This should open a new VS Code window which is running the modified version of vscode-R with your changes. If F5 doesn't work, could you let me know what happens (error message etc.)? Thank you.

[storopoli]

Ok. It doesn't render LaTeX for a given .Rmd file. Here is an example for a tutorial in Portuguese that I am developing for a Bayesian Statistics Course

[andycraig]

There's an error showing at the bottom right. My guess is that you need to build the extension. Here are some instructions: https://github.com/Ikuyadeu/vscode-R/wiki/Contributing

[storopoli]

I've managed to build it without errors. But unfortunately LaTeX doesn't render. How do I force LaTeX Workshop extension to be loaded with vscode-R in the F5 run?