code: public function addScalarArgument($name, $type, $required = true, $default = null)
  	{
  		return $this->addArgument(new ScalarArgument($this->argumentPosition++, $name, $type, $required, $default));
  	}
docs: Add a scalar argument to the factory definition.
  
  @param string  $name
  @param string  $type     int, string, object, etc.
  @param boolean $required
  @param mixed   $default  Default value, if not required