scripts methods questions

hi all,

here is my question:
"function ShapeBase::damage(%this, %sourceObject, %position, %damage, %damageType)
{
// All damage applied by one object to another should go through this
// method. This function is provided to allow objects some chance of
// overriding or processing damage values and types. As opposed to
// having weapons call ShapeBase::applyDamage directly.
// Damage is redirected to the datablock, this is standard proceedure
// for many built in callbacks.
%this.getDataBlock().damage(%this, %sourceObject, %position, %damage, %damageType);
}"


shapebase is a class in C++. damage is a method. How and where does the code know that it needs to be called?

thanks a bunch