Setup Instructions

Littleton is built mainly in OCaml. First, install dependencies using the following commands:

opam switch 4.11.0
eval $(opam env)
opam install alcotest async cohttp cohttp-async core menhir mparser mparser-re \
             ocamlgraph re toml yojson \
             ppx_deriving_yojson ppx_deriving ppx_jane ppx_sexp_conv \
             js_of_ocaml js_of_ocaml-ppx

Building the Interpreter and Interface

The Makefile includes instructions to build two versions of the Littleton interpreter. First, a native command-line executable (created as littleton) can be built using just make.

Secondly, the Makefile can generate a JavaScript version bundled with a web-based interface to the interpreter. This version can be built with make website (which also builds the native version). The website contents will be placed in _build/website, which can be served using your server software of choice. The website takes examples from the examples/ directory. To add a new set of examples, add a new .json file following the format of the ones present, and add the filename to examples/index.json.

The native executable also includes a simple web server so that you don't require any other software for the web interface. Run make website and run the server with misc/run-website.sh. The web interface will then be available at localhost:8000.

The design of the interface is partially inspired by the Rust playground.

Writing Examples

As noted above the web interface pulls examples in a JSON format from the examples/ directory. As a convenience, you can write examples in an example TOML format and use Littleton to convert them to json. ./littleton jsonify path/to/file.toml will create an equivalent path/to/file.json that you can put in examples/ and add to index.json.