每天laravel-20160801| Container -4

    /**
     * Register a binding with the container.
     * Register a binding with the container.
     * @param  string|array  $abstract
     * @param  \Closure|string|null  $concrete
     * @param  bool  $shared
     * @return void
     */
    public function bind($abstract, $concrete = null, $shared = false)
    {// bind abstract con
        $abstract = $this->normalize($abstract);// get the right normalize

        $concrete = $this->normalize($concrete);// get the right concrete

        // If the given types are actually an array, we will assume an alias is being
        // defined and will grab this "real" abstract class name and register this
        // alias with the container so that it can be used as a shortcut for it.

        // now i say,if they give us a array use a types.
        // so we need do something for it,
        // if the "real" abstract class name is too long,
        // we can use alias to defined the real class name as a shortcut name.

        if (is_array($abstract)) {// check the abstract name is a array
            list($abstract, $alias) = $this->extractAlias($abstract);// a array one is abstract , other is alias

            $this->alias($abstract, $alias);// return the result to the alias.
        }

        // If no concrete type was given, we will simply set the concrete type to the
        // abstract type. This will allow concrete type to be registered as shared
        // without being forced to state their classes in both of the parameter.

        // i coming ,if never give us a concrete type class, we will use a abstract type.
        // so they will be registered as shared .
        // no forced to state their classes in both of the parameter
        $this->dropStaleInstances($abstract);// then can drop the state Instances.

        if (is_null($concrete)) {
            $concrete = $abstract;
        }// if the concrete is null

        // If the factory is not a Closure, it means it is just a class name which is
        // bound into this container to the abstract type and we will just wrap it
        // up inside its own Closure to give us more convenience when extending.

        // if the instance of concrete not a Closure.
        // so it means it just a class name be used bound to a container.
        // may be it is a abstract type .
        // so we can use that self own Closure to wrap it.
        // to give us more function when it extending
        if (! $concrete instanceof Closure) {
            $concrete = $this->getClosure($abstract, $concrete);
        }// get the Closure, more like hook

        $this->bindings[$abstract] = compact(‘concrete‘, ‘shared‘);// a shared

        // If the abstract type was already resolved in this container we‘ll fire the
        // rebound listener so that any objects which have already gotten resolved
        // can have their copy of the object updated via the listener callbacks.

        // if the class name is ready resolved in the container.
        // so we will fire the rebound listener .
        // so that any objects which have already gotten resolved can have their copy
        // via the listener callbacks
        if ($this->resolved($abstract)) {// has the resolved
            $this->rebound($abstract);// set the rebound
        }
    }// too long too not simple