You'll need boris and boris-loader and then set a boris bootstrap for your Drupal repos.
Install boris however you prefer. I have a /usr/local/bin/boris symlink to the boris vendor binary under ~/.composer
Install boris-loader. I just cloned the repos to my homedir.
Set up a Drupal bootstrap in your local Drupal dirs.
Here's mine:
⟶ ~/projects/drupal/drupal-7.32
ben@Ben ❤ cat .borisrc
<?php
require '/Users/ben/local/boris-loader/boris-loader.php';
\Boris\Loader\Loader::load($boris, array(
new \Boris\Loader\Provider\Drupal7(),
));
In your Drupal directory type boris
to spawn the PHP REPL with a bootstrapped Drupal so you can use Drupal functions as well as PHP functions.