ocaml-mlx/mlx

OCaml .mlx syntax dialect with JSX syntax expressions

OCaml

148

119 commits

updated Sep 16, 2026

See the code

README

mlx

An OCaml syntax dialect which adds JSX expressions to the language.

let header ~title () =
  <header>
    <h1>title</h1>
  </header>

let page =
  <html>
    <body>
      <header title="Hello, world!" />
      <div>
        "Some content goes here"
      </div>
    </body>
  </html>

This code is transformed into the following OCaml code:

let header ~title () =
  header () ~children:[ h1 () ~children:[ title ] [@JSX]; ] [@JSX]

let page =
  html () ~children:[
    body () ~children:[
      header () ~title:"Hello, world!" [@JSX];
      div () ~children:[ "Some content goes here" ] [@JSX];
    ] [@JSX];
  ] [@JSX]

It is expected to use mlx-pp preprocessor with either a runtime lib which provides the implementation of such functions or a ppx which which further transforms [@JSX] attributes into the desired output.

Installation & Usage

Use the following commands to install the necessary packages:

opam install mlx ocamlmerlin-mlx

To make dune consider .mlx files as OCaml files you need to configure an mlx dialect, put this in your dune-project file:

(dialect
 (name mlx)
 (implementation
  (extension mlx)
  (merlin_reader mlx)
  (preprocess
   (run mlx-pp %{input-file}))))

Editor Support

VS Code

For VSCode and its forks (Cursor, Windsurf, etc.), install the Official OCaml Platform extension (version 2.0.0 or higher). It supports mlx syntax highlighting and all LSP features on par with .ml files.

Neovim

For Neovim users, install plugin: https://github.com/ocaml-mlx/ocaml_mlx.nvim

Emacs

For Emacs users, install mlx-mode: https://github.com/ocaml-mlx/emacs-mlx

Useful Links

Example with Dream web framework: https://github.com/aantron/dream/pull/330
Template ReasonReact project: https://github.com/andreypopp/melange-mlx-template
mlx announcement on OCaml Discourse: https://discuss.ocaml.org/t/ann-mlx-syntax-dialect/15035

Contributors

86 commits

28 commits

2 commits

1 commits

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ocaml-mlx/mlx

OCaml .mlx syntax dialect with JSX syntax expressions

OCaml

148

119 commits

updated Sep 16, 2026

See the code

README

mlx

An OCaml syntax dialect which adds JSX expressions to the language.

let header ~title () =
  <header>
    <h1>title</h1>
  </header>

let page =
  <html>
    <body>
      <header title="Hello, world!" />
      <div>
        "Some content goes here"
      </div>
    </body>
  </html>

This code is transformed into the following OCaml code:

let header ~title () =
  header () ~children:[ h1 () ~children:[ title ] [@JSX]; ] [@JSX]

let page =
  html () ~children:[
    body () ~children:[
      header () ~title:"Hello, world!" [@JSX];
      div () ~children:[ "Some content goes here" ] [@JSX];
    ] [@JSX];
  ] [@JSX]

Installation & Usage

Use the following commands to install the necessary packages:

opam install mlx ocamlmerlin-mlx

To make dune consider .mlx files as OCaml files you need to configure an mlx dialect, put this in your dune-project file:

(dialect
 (name mlx)
 (implementation
  (extension mlx)
  (merlin_reader mlx)
  (preprocess
   (run mlx-pp %{input-file}))))

Editor Support

VS Code

Neovim

For Neovim users, install plugin: https://github.com/ocaml-mlx/ocaml_mlx.nvim

Emacs

For Emacs users, install mlx-mode: https://github.com/ocaml-mlx/emacs-mlx

Useful Links

Example with Dream web framework: https://github.com/aantron/dream/pull/330
Template ReasonReact project: https://github.com/andreypopp/melange-mlx-template
mlx announcement on OCaml Discourse: https://discuss.ocaml.org/t/ann-mlx-syntax-dialect/15035

Similar repos

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davesnx/html_of_jsx

Render HTML with JSX

ml-in-barcelona/jsoo-react

js_of_ocaml bindings for ReactJS. Based on ReasonReact.

138

tomasr8/pyjsx

Write JSX directly in Python

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ozanvos/ppx-tea-jsx

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Build valid HTML and SVG documents

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Contributors

86 commits

28 commits

2 commits

1 commits

Languages

OCaml

99.8%