In object-oriented programming class is a set (a transitive closure) of types bound by the relation of inheritance. It is said that all types derived from some base type T and the type T itself form a class T.

The first type T from the class T sometimes is called the root type of the class.

A class of types itself, as a type, has the values and operations of its own.
The operations of are usually called methods of the root type.
Both operations and values are called  polymorphic.

A polymorphic operation (method) selects an implementation depending on the actual specific type of the polymorphic argument.

The action of choice the type-specific implementation of a polymorphic operation is called dispatch. Correspondingly, polymorphic operations are often called dispatching or virtual.
Operations with multiple arguments and/or the results of the class are called multi-methods.
A further generalization of is the operation with arguments and/or results from different classes.

 single-dispatch languages are those that allow only one argument or result to control the dispatch. Usually it is the first parameter, often hidden, so that a prefix notation x.f() is used instead of mathematical f(x).
 multiple-dispatch languages allow many arguments and/or results to control the dispatch.


A polymorphic value has a type tag indicating its specific type from the class and the corresponding specific value of that type.
This type is sometimes called the most specific type of a [polymorphic] value.
The type tag of the value is used in order to resolve the dispatch.
The set of polymorphic values of a class is a transitive closure of the sets of values of all types from that class.

In many  OO languages
the type of the class of T and T itself are considered equivalent.
In some languages they are distinct (like in Ada).
When class T and T are equivalent, there is no way to distinguish
polymorphic and specific values.



Task

Create a basic class with a method, a constructor, an instance variable and how to instantiate it.




 
define mytype => type {
	data
		public id::integer		= 0,
		public val::string		= '',
		public rand::integer	= 0
 
	public onCreate() => {
		// "onCreate" runs when instance created, populates .rand
		.rand = math_random(50,1)
	}
	public asString() => {
		return 'has a value of: "'+.val+'" and a rand number of "'+.rand+'"'
	}
 
}
 
local(x = mytype)
#x->val = '99 Bottles of beer'
#x->asString // outputs 'has a value of: "99 Bottles of beer" and a rand number of "48"'