classes/Factory/Definition.php
public function addOptionalScalarArgument($name, $type, $default)
	{
		return $this->addArgument(new ScalarArgument($this->argumentPosition++, $name, $type, false, $default));
	}
public function addOptionalScalarArgument($name, $type, $default)
	{
		return $this->addArgument(new ScalarArgument($this->argumentPosition++, $name, $type, false, $default));
	}
Add an optional scalar argument to the factory definition.

@param string  $name
@param string  $type    int, string, object, etc.
@param mixed   $default