package highlexer

Highlexer

This library provides a way to highlight OCaml source. It is designed for use with js_of_ocaml, but does not have to be used this way.

Because the jsoo code elimination does not work well with the compiler-libs, this library uses a modified version of the OCaml lexer. This version has worse error messages, and docstrings simplified, because these features required vendoring much more files from the OCaml source code.

Here is an example of how to use highlexer with js_of_ocaml and brr :

open Brr

let ( .%{} ) obj prop = Jv.get obj prop

let ( !% ) = Jstr.of_string

let highlight_snippet el =
  Console.log [!%"highlighting"; el] ;
  let src =
    (El.to_jv el).%{"innerHTML"} |> Jv.to_string |> Highlexer.unescape
  in
  let annotated = Highlexer.of_string src in
  let html =
    List.map
      (fun Highlexer.{tag; content} ->
        match tag with
        | Some tag ->
            El.(span ~at:At.[class' !%tag] [txt !%content])
        | None ->
            El.txt !%content )
      annotated
  in
  El.set_children el html

let () =
  let ocaml_snippets = Brr.El.find_by_class !%"language-ocaml" in
  Console.log ["ocaml snippets"; ocaml_snippets] ;
  List.iter highlight_snippet ocaml_snippets

This example had a size of 168K. This may improve a little bit with new versions of `js_of_ocaml``, but the lexing table itself is 104K, so it will never be super small like a highlighter with just a few regexp could.

If you are bothered by the size, it is perfectly fine to use this in the backend instead.