每天laravel-20160820| ContextualBinding

<?phpnamespace Illuminate\Container;use Illuminate\Contracts\Container\ContextualBindingBuilder as ContextualBindingBuilderContract;class ContextualBindingBuilder implements ContextualBindingBuilderContract{    /**     * The underlying container instance.     *     * @var \Illuminate\Container\Container     */    protected $container;// The underlying container instance    /**     * The concrete instance.     *     * @var string     */    protected $concrete;// a instance about concrete    /**     * The abstract target.     *     * @var string     */    protected $needs;// a target about the abstract    /**     * Create a new contextual binding builder.     *     * @param  \Illuminate\Container\Container  $container     * @param  string  $concrete     * @return void     */    public function __construct(Container $container, $concrete)    {        $this->concrete = $concrete;        $this->container = $container;// set the    }    /**     * Define the abstract target that depends on the context.     *     * @param  string  $abstract     * @return $this     */    public function needs($abstract)    {        $this->needs = $abstract;        return $this;    }// function is needs    /**     * Define the implementation for the contextual binding.     *     * @param  \Closure|string  $implementation     * @return void     */    public function give($implementation)    {        $this->container->addContextualBinding($this->concrete, $this->needs, $implementation);    }// Define the implementation for the contextual binding}