Pinq\Iterators\Generators\JoinIterator::walk PHP Method

    public function walk(callable $function)
    {
        $data = $this->beforeOuterLoopData();
        foreach ($this->outerIterator as $outerKey => &$outerValue) {
            foreach ($this->innerGenerator($outerKey, $outerValue, $data) as $innerKey => &$innerValue) {
                $function($outerValue, $innerValue, $outerKey, $innerKey);
            }
        }
    }