sclass InputProcessor1 {
  new Map<S, virtual F1<S, O>> propertyMakers;
  
  class Out > PropertiesAndErrors {
    S input;
    
    O getProperty(S name) {
      if (properties.containsKey(name)) ret properties.get(name);
      if (propertyErrors.containsKey(name)) throw throwPersistableThrowable(propertyErrors.get(name));
      O f = propertyMakers.get(name);
      if (f == null) null;
      callFAndPutInResultOrErrorMap(properties, propertyErrors, input, f, input);
      if (propertyErrors.containsKey(name)) throw throwPersistableThrowable(propertyErrors.get(name));
      ret properties.get(name);
   }
  }

  Out process(S input) {
    Out out = nu(+input);
    for (S name, O f : propertyMakers)
      callFAndPutInResultOrErrorMap(out.properties, out.propertyErrors, input, f, input);
    ret out;
  }
  
  // you can query properties on demand
  Out dontProcess(S input) {
    ret nu Out(+input);
  }
}