View file vendor/laravel/framework/src/Illuminate/Contracts/Routing/BindingRegistrar.php
<?php namespace Illuminate\Contracts\Routing; interface BindingRegistrar { /** * Add a new route parameter binder. * * @param string $key * @param string|callable $binder * @return void */ public function bind($key, $binder); /** * Get the binding callback for a given binding. * * @param string $key * @return \Closure */ public function getBindingCallback($key); }