Simple implementation of range as a generator

range.php

<?php

$data = range(0, 1000000);

echo sprintf('%02.2f', (memory_get_usage() / 1048576))." MB of memory used\n";

// output: 137.92 MB of memory used

foreach ($data as $key => $val) {
    //echo "key: ".$key." value: ".$val."\n";
}

yield.php

<?php

/**
 * Simple implementation of range() as a generator
 * @param int $start
 * @param int $end
 * @return void
 */
function range_yield($start, $end) {
    for ($index = $start; $index <= $end; $index++) {
        yield $index => $index;
    }
}

$data = range_yield(0, 1000000);

echo sprintf('%02.2f', (memory_get_usage() / 1048576))." MB of memory used\n";

// output: 0.22 MB of memory used

foreach ($data as $key => $val) {
    //echo "key: ".$key." value: ".$val."\n";
}