Comments highlighting / parsing

[paulhenri]

Hi,
The following issue occurs with neovim, i can't speak for other editors.

We have issues when using this form of comments <% # Some comment %> instead of this form <%# Some comment %>
If we pass on the comment line every following lines are seens as a comment (See picture below)

We tried to tweak to the parser to handle this case by changing the _hash_comment function like so :

_hash_comment: ($) => seq(/<%[\s]*#/, prec.left(seq(repeat($._code), "%>"))),

Parsing tests do work fine with this function, even with changed cases to reflect the change but highlights one do not :

Error in query file "highlights.scm"
Caused by:
    Query error at 11:4. Invalid node type

We are willing to make a Pull request to change this behavior once it works we are just looking for some hints or direction to solve the problem.

[the-mikedavis]

I can't reproduce this in Helix so I think this may be an issue with the nvim-treesitter queries or the version of the parser it is using.

That error comes from this line in the queries: once _hash_comment no longer uses a literal "<%#" token, tree-sitter's query analysis will say that the <%# node is not a valid node type to query for.

I think that adding extra space at the beginning is not a robust fix though - I suspect that the same problem would happen if you had comments after code like <%= gettext(..) # comment %>.

[paulhenri]

The problem is clearly with nvim-treetsitter or i would think so ; I tried to use helix queries or even the one provided here, elixir code is simply not highlighted anymore.

I am gonna dig more and get more informations. Thank you for you input.

Paul-H

[SichangHe]

Is this related? Also on Neovim.

[paulhenri]

To me it is, the colorisation has various problem but nvim-treesitter uses its own set of queries and even some that are not here so... To be honest i don't know how to approach this right now and every attempts i have made have been unsuccessful.

[connorlay]

The difference between <%# and <% # is how they are parsed: the first version is a HEEx comment, while the second version is a HEEx directive. HEEx directives allow for interpolation of arbitrary Elixir code into your HEEx code. In other words, <%# a comment %> is parsed and highlighted using just the HEEx grammar, while <% # a comment %> is parsed and highlighted using both the HEEx grammar and the Elixir grammar.

Each editor that uses tree-sitter defines its own set of captures and highlighting logic. Given this is not reproducible in Helix, I think this is an issue specific to nvim-treesitter and not with tree-sitter-heex itself.

@paulhenri I suggest opening an issue in nvim-treesitter as that is likely where the fix will have to be made.

[SichangHe]

As an aside, is it worth it to move to Helix for Phoenix development? Thanks.

[the-mikedavis]

I can't reproduce those highlighting bugs in Helix @SichangHe. I think that neovim might be behind on the version of this parser or there might be something odd happening with the injection queries.

I'm definitely biased since I work on Helix but I think it's a nice choice for working in an Elixir and/or Phoenix codebase. I believe it should be possible to highlight these snippets correctly in nvim too though.