catala/INSTALL.md

# Building and installing the Catala language

## Requirements

### With Docker

The Catala compiler is written using OCaml. The repository provides a `Dockerfile`
to build a Docker image with all the dependencies required to build the Catala compiler.

Start by installing Docker: https://docs.docker.com/get-docker/

Then build the Docker image:

    docker build . --target dev-build-context -t catala

Finally, start a shell inside a new container created from the newly built image:

    docker run -it --name catala catala

### With nix

The repository provides nix files to build or develop the catala compiler.

Once [nix is installed](https://nixos.org/manual/nix/stable/#ch-installing-binary),
it is possible to enter a development shell:

    nix-shell

or to build the Catala compiler, documentation and runtime library:

    nix-build release.nix

Dependencies not yet in nixpkgs (`bindlib` and `unionFind` at the moment of writing)
are hardcoded inside the `.nix` directory. The `default.nix` should be compatible with
nixpkgs, if it finds a maintainer.

### With opam

The Catala compiler is written using OCaml. First, you have to install `opam`,
OCaml's distribution and package manager. Follow the [instructions on the `opam`
website](https://opam.ocaml.org/doc/Install.html).

Next, you will need to use the correct version of OCaml. Catala has been tested
with OCaml compiler versions that are at least 4.13.0. To switch to OCaml 4.13.0.,
just use:

    opam switch 4.13.0

If you get a `No switch 4.13.0 is currently installed` error message, follow
the hint and enter `opam switch create 4.13.0`.

## Dependencies

You can skip this step if you used the *Docker* option above, it is already taken
care of.

Next, install all the packages that Catala depends on with

    make dependencies

This should ensure everything is set up for developing on the Catala compiler!

**Warning**: this command does not include the `z3` dependency required to enable
the proof platform feature of Catala. If you wish to enable support for the
proof platform and the `Proof` command of the Catala compiler, you should
instead execute `make dependencies-with-z3` prior to building the compiler.

Other features of the Catala repository also require the following executables
to be present. On debian, arch or apline-based distributions, the above command
should already take care of them.

    groff virtualenv python3 pip rsync colordiff pygmentize nodejs npm

## Build

The project is distributed as a Dune artifact. Use standard dune commands to build
and install the library. Makefile aliases are here to help you: running

    make build

builds the compiler from its OCaml sources.

## Install

The installation of the Catala compiler is handled through `opam`. Since the
Catala compiler is not yet published to the `opam` repository, you can install
a local version from this Git repository by using

    opam install ./

To uninstall, use

    opam unpin catala

### Generating website assets

The Catala website features assets generated by the Catala compiler. They are
needed to build the website. To produce them, simply run

    make website-assets

Then, use a helper script to copy them over to the `assets` directory of the
Catala website.

    ./generate_website_assets.sh <path-to-catala-website>/assets

You will need the `groff` executable to generate the HTML versions of the man
pages, as well as the `rsync` executable to transfer files (preferred to `cp`)
because it also works with a remote server.

## Syntax highlighting

See the [dedicated `README.md`](./syntax_highlighting/README.md).