Don't know about ProseMirror but I found the documentation for writing CodeMirror syntax highlighters to be very scarce.. The syntax files themselves look like

Don't know about ProseMirror but I found the documentation for writing CodeMirror syntax highlighters to be very scarce.. The syntax files themselves look like huge procedural JS files with barely a comment :( But apart from that, CM works like a charm out of the box, so thanks a ton for it :)