lorri uses direnv, because direnv has dozens of integrations for editors, shells and the like . Basically everywhere you want to change an environment on the fly, you can use direnv.

In particular, there is integration for the Emacs editor, emacs-direnv.

Follow the emacs-direnv setup guide now.

Note: There are direnv plugins for many editors. Just a few, vscode, Sublime, vim, Atom.

Once you have it installed, hit M-x and enter direnv-mode. This activates direnv integration for every buffer.

Use the the Emacs file browser to navigate to lorri/example and open shell.nix. If everything went fine, you should see the same list of environment variables in your Emacs status line that you previously saw in your shell. Congratulations, you have working direnv integration in your editor, and therefore also working lorri integration.

direnv-mode updates your environment every time you enter a buffer that is in a project with a different .envrc file. To manually apply changes, hit M-x and enter direnv-update-environment.

Try playing around with the shell.nix file, removing and adding things. For example, add an environment variable:

with import ../nix/nixpkgs.nix;
mkShell {
  buildInputs = [];

  MYVARIABLE = "hi";
}

Wait until the evaluation finishes and refresh your direnv environment (M-x direnv-update-environment). Your status line shows that MYVARIABLE was added to the environment. Comment out MYVARIABLE and refresh, it is removed from the environment again.

Note: If you are developing rust in emacs and would like to use emacs-racer, you can do so in a lorri direnv by setting

    (setq racer-rust-src-path nil) ;; read from shell-nix
    (setq racer-cmd "racer")