Method

The DEFINE command can be used to define new methods on user defined or predefined classes. A method is similar to a function, except that it is associated with objects of a particular type (Class).

  DEF[INE] METHOD method_name ( arg1, arg2, ... ) ON class_name
    command_list ...
  ENDDEFINE

The object on which the method is invoked will be known as 'this' within the method.

If the method is named Initialize(), then it will be used as a constructor for the class. It will be automatically invoked each time an object of the class is created. Normally, the constructor is used to assign initial values to the class fields. The Initialize() method cannot take any arguments.

If the method is named Destroy(), then it will be used as a destructor for objects in the class. It will be automatically invoked each time an object of the class is destroyed. Normally, the destructor is used to free any additional memory associated with the class.

Example:

Define a class called Circle with two initialization methods.

 DEFINE CLASS Circle
   ReadOnly
     double            CenterX
     double            CenterY
     double            Radius
     double            Area
   EndReadOnly     
 ENDDEFINE

 DEFINE METHOD SetCenter( x, y ) ON Circle
   this.CenterX = x
   this.CenterY = y
 ENDDEFINE

 DEFINE METHOD SetRadius( new_radius ) ON Circle
   this.Radius = new_radius
   this.Area = 3.1415927 * this.Radius * this.Radius
 ENDDEFINE