CM6 lint + gutter + widget

I took a leap and started my journey with CM6. Implemented my own language pack (lezer parser is magical!), found an AST builder for Lua and now I would like to add lint errors in the gutter and maybe inline too as seen in this example:

Checked the source for the above demo and the doc.addLineWidget seem to be not available in CM6. Also didnt’ find a way to use doc.setGutterMarker, it would be cool to update a gutter line programatically (based on the AST tree built from LUA).

Checked out this thread too for inspiration, but honestly I feel stuck. Any pointers appreciated.

You could take a look at the fold gutter (in @codemirror/fold) for an example of how to show a gutter with markers. For linting, I’d start with the lint package though—that doesn’t show gutter markers, but has support for underlining problems and showing a list of them.