import objectdraw.*;

/*
 * A stack of VisibleImages.  This interface
 * captures what is common about all stacks.
 */
public interface StackInterface {

        // Returns true if the stack is empty
        public boolean isEmpty();
        
        // Returns the first image in the stack
        // Pre-condition: 
        //     the stack is not an empty stack.
        public VisibleImage getFirst();
        
        // Returns the rest of the stack, after
        // the first image.
        // Pre-condition: 
        //     the stack is not an empty stack.
        public StackInterface getRest();
        
}