// Idea: Every class loader makes only a single class  so they can be
// garbage collected more easily.

srecord noeq LASMultiClassLoader(ClassLoader parent) is ILASClassLoader, AutoCloseable {
  settable bool rememberClassBytes;
  
  new WeakValueMap<S, Class> definedClasses;
  Lock lock = lock();
  
  event classDefined(Class c);
  
  *(Class parent) { this(parent.getClassLoader()); }
  
  {
    definedClasses.onValueForKeyReleased(key -> 
      printWithMS(":: CLASS UNLOADED :: " + key));
  }
  
  selfType runnablesReferenceQueue(RunnablesReferenceQueue queue)  {
    definedClasses.queue(queue);
    this;
  }
  
  int nClassesLoaded() { ret l(definedClasses); }
  
  Cl<Class> definedClasses() {
    ret values(definedClasses.snapshot());
  }
  
  public Class<?> defineLASClass(S name, IF0<byte[]> generateClass) {
    lock lock;
    
    try object definedClasses.get(name);
    
    var cl = new IndividualClassLoader().rememberClassBytes(rememberClassBytes);
    print("Generating class " + name);
    byte[] bytes = generateClass!;
    if (bytes == null)
      fail("No class bytes generated for " + name);
    Class c = cl.defineAClass(name, bytes);
    definedClasses.put(name, c);
    classDefined(c);
    ret c;
  }
  
  close {
    dispose definedClasses;
  }
  
  class IndividualClassLoader extends InMemoryClassLoader {
    *() { super(parent); }
    
    // Allows one script-defined class to see another one
    protected Class<?> findClass(S name) throws ClassNotFoundException {
      try object definedClasses.get(name);
      ret super.findClass(name);
    } 
  }
}

Began life as a copy of #1035083