Sticky lines for chapter + section

[jojo2357]

In IDES circa 2024, they added sticky lines. While it works for a lot of tokens, it does not work for \chapter or \section tokens, which I would think are important to know where you are in the tex.

I think this should be obvious to replicate? just add a \chapter and a lot of lines and scroll down and see that it doesnt end up at the sticky lines

[PHPirates]

Not sure if this is possible, do you have any idea how they determine scopes? Don't see anything in the intellij sdk docs yet about sticky lines

[jojo2357]

Absolutely no idea, only hunch is that it uses environs that close and open? Cuz \begin{figure} sticks, so I presume we somehow need to make chapters and sections a thing? how? based off spacing? Yikes.

[PHPirates]

I asked at jetbrains slack channel and Scott Wells replied:

It's all based on the breadcrumbsInfoProvider EP. Implement that properly for your language, and the elements included in the breadcrumb trail are the same ones used for sticky line scopes.

To be specific, for my plugin's custom language, I had to implement the following methods in BreadcrumbsProvider properly:
getLanguages()
acceptElement()
getElementInfo()
getElementTooltip()
I believe the latter two are more specific to the way things look in the breadcrumb than to sticky lines.
With those properly implemented, though, it works wonderfully:

[jojo2357]

Okay, I checked and every command is being accepted (so if there was such thing as a multiline command, then it would be sticking.

I am 99% sure that the reason that it isnt sticking is the fact that the element being accepted is ONLY the \chapter command. If the chapter was similar to an environment and had an implicit ending, then the token would be large and would be stickable.

[PHPirates]

Yeah I guess that's the only way it can determine the scope. I don't see an easy way to add sectioning commands to the parser without breaking a lot of things though.

[jojo2357]

I want to give it a shot, and I'm not sure where to start. Starting in the bnf or flex is very static, and not future-proof. It would be really nice if there was some way to define a weak environment that gets added to the PSI/AST after lexing. That way we could go so far as to make chapter/sections configurable in settings so the user can define their own sectioning commands.

Thoughts @PHPirates ?

[PHPirates]

Querying user settings from the lexer is probably not a good idea because it will make the lexer slow. There are also token type remappers (LatexParserUtil) for parser level, but they are not easy to use.

[jojo2357]

I saw those, and I concured that they are hard to use.

For such a new feature I think it would be fine to wait a little to see what happens. We have folding for the chapter so secretly im hoping we will be able to recycle that.