Class TStack

        Exported Instances:

        Exported Methods:

           Init()       Constructor Method
           Push()       Adds an element into the stack
           Pop()        Extracts an element
           Len()        Returns the lenght of the stack
           Empty()      Determines if the stack is empty
           Tail()       Returns the highest element

        Function Demo()
        Local oStack := TStack():Init()
            oStack:Push( "Hello" )
            oStack:Len()                // 1
            oStack:Empty()              // .F.
            oStack:Tail()               // "Hello"
            ? oStack:Pop()              // "Hello"
            oStack:Empty()              // .T.
            oStack:Len()                // 0
        Return( Nil )