Cairo Env for Vim

cairo_vim_env.md

Setting up Cairo env for vim development

Setup the cairo virtualenv

First things first, you need to install the cairo-lang package, preferably in a virtual env you can later use and upgrade. Currently only python 3.7 and 3.8 is supported

python3 -m venv ~/cairo_venv
source ~/cairo_venv/bin/activate

You can also add an alias in .bashrc to quickly source the cairo env file in the future

alias source_cairo='source /home/$USER/cairo_venv/bin/activate'

It is also recommended to install starknet-devnet for local testing

pip install starknet-devent

For further info checkout the cairo-lang quick-start

Setting up a language server

To easily get auto-complete functionality as well as some just-to-definition functionality, you can use the cairo language server cairo-ls

Installation instructions for vim functionality:

1. Install Coc

2. In an empty directory, run npm install cairo-ls. This can also be installed as a global dir, then your DIR in step 3 is ~/ or a direct path to the user home dir

3. Run Vim, then use :CocConfig command to edit coc-settings.json with the following:

{
    "languageserver": {
        "cairo": {
            "module": "YOUR_DIRECTORY_FROM_STEP_2/node_modules/cairo-ls/out/server.js",
            "args": ["--node-ipc"],
            "filetypes": ["cairo"],
            "rootPatterns": [".git/"]
       }
    }
}

4. Add the following to ~/.vimrc

au BufReadPost *.cairo set filetype=cairo
au Filetype cairo set syntax=cairo

5. Optionally you can add the Coc's example Vim configuration to ~/.vimrc

Syntax highlight

For syntax highlighting, download https://github.com/starkware-libs/cairo-lang/blob/master/src/starkware/cairo/lang/ide/vim/syntax/cairo.vim to ~/.vim/syntax/

Auto-Format

The cairo virtual env comes with the executable cairo-format that formats the cairo code with pre-defined conventions.

The executable receives the -i tag to modify and save the file in place

To Run the auto-format code on-save when using vim, add this to your vimrc:

:autocmd BufWritePost *.cairo silent ! cairo-format % -i  2> /dev/null

This will format the current buffer in place. The command will do nothing if cairo_venv is not activated