Class Specialization

• Syntax:

  CLASS class_name "description" SPECIALISES spec_type_or_class_name := [object_assignment];
  

  "class_name" is the name of the class
  "description" is a string expression
  "spec_type_or_class_name" is the name of the class or type used to specialize from
  "object_assignment" is the assignment of the objects in the class

• Description:

  A class that is specialized from another class (or type) has the same signature, but the objects in the class are assigned (replaced) as specified in "object_assignment". This can be done recursively: the object in a class can itself consist of other objects.

  Example:

  TYPE PhysicalQuantityType "The type of any physical quantity" =
  RECORD
  {
    Quantity : QuantityType;
    Unit : UnitType;
  };
  
  CLASS Length "A class for length"
  SPECIALISES PhysicalQuantityType :=
  {:
    Quantity <- "Length";
    Unit     <- "m";
  :};