Type animal Extends Object ' 'Extends' to activate RTTI by inheritance of the predefined Object type
   Declare Constructor (Byref _name As String = "")
   Declare Function ObjectHierarchy () As String
   Declare Function ObjectType () As String
   Dim name As String
End Type

Constructor animal (Byref _name As String = "")
   This.name = _name
End Constructor

Function animal.ObjectHierarchy () As String
   Return "Object(forRTTI) <- animal"
End Function

Type dog Extends animal ' 'Extends' to inherit of animal
   Declare Constructor (Byref _name As String = "")
   Declare Function ObjectHierarchy () As String
End Type ' derived type may be member data empty

Constructor dog (Byref _name As String = "")
   Base(_name) ' 'Base()' allows to call parent constructor
End Constructor

Function dog.ObjectHierarchy () As String
   Return Base.ObjectHierarchy & " <- dog" ' 'Base.' allows to access to parent member function
End Function

Type cat Extends animal ' 'Extends' to inherit of animal
   Declare Constructor (Byref _name As String = "")
   Declare Function ObjectHierarchy () As String
End Type ' derived type may be member data empty

Constructor cat (Byref _name As String = "")
   Base(_name) ' 'Base()' allows to call parent constructor
End Constructor

Function cat.ObjectHierarchy () As String
   Return Base.ObjectHierarchy & " <- cat" ' 'Base.' allows to access to parent member function
End Function

Function animal.ObjectType () As String ' must be put after definition of dog type and cat type
   If This Is dog Then ' 'Is' allows to check compatibility with type symbol
     Return "dog"
   Elseif This Is cat Then ' 'Is' allows to check compatibility with type symbol
     Return "cat"
   Else
     Return "animal"
   End If
End Function

Print "Name:", "Object:", "Hierarchy:"
Dim a As animal = animal("Mouse")
Print "  " & a.name, "  " & a.ObjectType, "  " & a.ObjectHierarchy
Dim d As dog = dog("Buddy")
Print "  " & d.name, "  " & d.ObjectType, "  " & d.ObjectHierarchy
Dim c As cat = cat("Tiger")
Print "  " & c.name, "  " & c.ObjectType, "  " & c.ObjectHierarchy

Sleep