Block comment higlighting (with a "|")

[alenkis]

Hi!

I've noticed that comments like this

--| ...
foo x = y

fail to properly hightlight as comments, and what I see is this:

I've tried to fix this on my end by adding

(add-hook 'purescript-mode-hook
          (lambda ()
            (font-lock-add-keywords nil
                                    '(("--|.*" . font-lock-comment-face)))))

But this doesn't fully solve the problem, as ocassionally keywords appear in the comment line, which somehow breaks the comment highlighting 🤷‍♂️

Is this supported? Any advice on how to fix it?
Thanks!

[kritzcreek]

Is this supported? Any advice on how to fix it?

Sorry unfortunately I have no clue :D

My hope is that at some point we can switch over to tree-sitter based highlighting. If you do manage to figure it out, I'd be happy to accept a PR

[Hi-Angel]

Haven't looked at it, but I hope it's a bit less of a problem for the latest master, because some keywords were made top-level only, and also default was removed (as it isn't a thing in PS), which might be a frequent word in comments as well.

[Hi-Angel]

@alenkis soo… I just looked at it and I figure I am not completely sure the syntax you're using is correct… Well, there is a bug, but I don't think it's the one we may be thinking there is… More specifically, it is unclear if the "no-space" --| should be considered a plain comment or a documentation comment.

Problem is triggered by absence of space between the dashes and the pipe, like --| instead of -- |. Whoever wrote the syntax highlight left a comment there should be a space.

I went to see what other editors have, and…

well, Visual Studio Code has exactly the same bug.

Official documentation also has a space, but it makes no claims on whether it's mandatory, so 🤷‍♂️ It does refer to some psc-docs though, whose behavior could be the reference we're interested in; but purescript devel group has no such package.

I'm going to CC @megamaddu for good measure as the author of the comments on screenshot in this file, since we have at least two major code editors where they're rendered incorrectly 😊

[Hi-Angel]

@alenkis I see you left an emoji, but since you're the bug author I'd be interested to hear how you expect this to work.

[Hi-Angel]

Or maybe @kritzcreek knows, since he's in the thread as well.

[Hi-Angel]

If no one answers, I think I'll just make it plain comment, because looking at Haskell haddoc docs (which PureScript was derived from) they also expect there to be a space.

P.S. fun fact, went to look how haskell mode highlights that — guess what? Same bug.

[Hi-Angel]

At the same time, looking at pursuit documentation for the problematic file, it renders just fine. Omg, why is everything so complicated…