每天laravel-20160807| Container -10

/**
     * Alias a type to a different name.
     *
     * @param  string  $abstract
     * @param  string  $alias
     * @return void
     */
    public function alias($abstract, $alias)
    {
        $this->aliases[$alias] = $this->normalize($abstract);// i know this ,set the alias as a key , abstract function as a value.
    }// a easy function that to set a alias for a different name

    /**
     * Extract the type and alias from a given definition.
     *
     * @param  array  $definition
     * @return array
     */
    protected function extractAlias(array $definition)
    {
        return [key($definition), current($definition)];
    }// function 'key' is get the current key.
    // function 'current' is get the current value,
    // so that means to get the current array