How to access constant defined in child class from parent class functions?

Question

I saw this example from php.net:

Answer 1

If you need to access constants, properties, methods of classes or objects you can use reflection, it provides much more details about structure of the object.
example:

class MainClass
{
    const name = 'Primary';

    public $foo = 'Foo Variable';
}
class ExtendedClass extends MainClass
{
    const name = 'Extended';
}

/**
 * From Class Name
 */

//get reflection of main class
$mainReflection = new ReflectionClass('MainClass');

if($mainReflection->hasConstant('name'))
    var_dump($mainReflection->getConstant('name'));//Primary

//get reflection of extended class
$extendedReflection = new ReflectionClass('ExtendedClass');

if($extendedReflection->hasConstant('name'))
    var_dump($extendedReflection->getConstant('name'));//Extended

/**
 * From Objects
 */
$main = new MainClass();
$extended = new ExtendedClass();

//get reflection of main class
$mainReflection = new ReflectionObject($main);

if($mainReflection->hasConstant('name'))
    var_dump($mainReflection->getConstant('name'));//Primary

//get reflection of extended class
$extendedReflection = new ReflectionObject($extended);

if($extendedReflection->hasConstant('name'))
    var_dump($extendedReflection->getConstant('name'));//Extended