// bool HasAggregation;
// T argument;
// Predicate<T> check;
// Action<T> visit;

// #1
if(!(HasAggregation = HasAggregation || check(argument))) {
  visit(argument);
}//if

// #2
if(!HasAggregation && !(HasAggregation = check(argument))) {
  visit(argument);
}//if

// #3
if(!HasAggregation) {
  HasAggregation = check(argument);
  if(!HasAggregation) {
    visit(argument);
  }//if
}//if

// #4
if(!HasAggregation) {
  if(check(argument)) {
    HasAggregation = true;
  } else {
    visit(argument);
  }//if
}//if