catala/INSTALL.md

# Building and installing the Catala language

## Requirements

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 4.09.1. To switch to OCaml 4.09.1.,
just use:

    opam switch 4.09.1

If you get a `No switch 4.09.1 is currently installed` error message, follow 
the hint and enter `opam switch create 4.09.1`.

Next, install all the OCaml packages that Catala depend on, as well as some 
git submodules, with

    make install-dependencies

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

Other features for generation of files and literate programming also require
the following executables to be present

    man2html virtualenv python3 rsync

please install them if they're not here. On a Debian distribution, this can be
done with

    sudo apt install python3-dev python3-setuptools man2html rsync
    sudo python3 -m pip install --upgrade pip
    sudo python3 -m pip install virtualenv

On ArchLinux :

    sudo pacman -S python-virtualenv man2html rsync

## 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 `man2html` 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

The Catala language also comes with syntax highlighting to
ease program development. The syntax highlighting is done
with the [Iro](https://eeyo.io/iro/) compiler that allows
writing the syntax only once, and then export it to formats
understood by various IDE. Currently, two syntax
highlighting plugins are under version control.

### Atom

To get Catala syntax highlighting in Atom, simply enter from
the root of the repository, depending on the language you want to use :

    make atom_fr
or

    make atom_en

You can now reload Atom and check that you have syntax highlighting on any `.catala` file.

### VSCode

To get Catala syntax highlighting in VSCode, simply enter from
the root of the repository, depending on the language you want to use :

    make vscode_fr
or

    make vscode_en

You can now reload VSCode and check that you have syntax highlighting on any `.catala` file.


### Pygments

Pygments is a Python-based versatile lexer for various
programming languages. To use a version of Pygments
augmented with the Catala plugin, simply enter

    make pygments

This will execute the
script `syntax_highlighting/fr/pygments/set_up_pygments.sh` and 
`syntax_highlighting/en/pygments/set_up_pygments.sh`.

The scripts set up a virtual environement in
`syntax_highlighting/fr/pygments/pygments/env` or
`syntax_highlighting/en/pygments/pygments/env`, which will
contain the modified version of Pygments that has Catala
support. If you want to hack something, it is possible to use this virtual
environnement directly with

    source syntax_highlighting/fr/pygments/pygments/env/bin/activate

or

    source syntax_highlighting/en/pygments/pygments/env/bin/activate

The `pigmentize` executable, used for instance by the `minted` LaTeX package,
will now point to the Catala-enabled version inside the virtual environment.
This `source` setup is not necessary if you use the rules in the `Makefile`.