Red-Black Trees: Testing on Empty

Now, what questions might we want to ask of a mapping?

We might want to know whether it was empty or not:

    linux$ my

    eval:  include package   string_map;

    eval:  m = empty: Map( String );

    eval:  is_empty m;

    TRUE

    eval:  m $= ("Key1", "Value1");

    eval:  is_empty m;

    FALSE