Re: RFC Draft: Comprehensions

> But $filteredArrayIterator->next() is actually $arrayIterator->next() with > a built-in if check, so you could also picture it as doing this: > > while ( $element = $arrayIterator->nextIf ( someCondition ) ) { > $newArray[] = $element; > } > In this case nextIf() would have to be implemented something like: function nextif($someCondition) { foreach($this->iteratorValue as $x) { if(<some comparison of $x and $$someCondition) { yield $x; } } } iterator_to_array would need an internal loop to pull the values from the generator. Thus, as far as I can see, the generator implementation would result in two loops running in lock step, rather than only one in the eager case. You do make a good point about the potential for the optimiser to recognise and automatically deal with such cases however.