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();

}