code: public void registerInclude(String programName, RecursiveTypeRegistry registry) {
          if (registry == this) {
              throw new IllegalArgumentException("Registering include back to itself: " + programName);
          }
          if (includes.containsKey(programName)) {
              return;
          }
          includes.put(programName, registry);
      }
docs: Register a recursive included registry.
  
  @param programName The program to be included.
  @param registry The registry for the given program.