PHP Generator as basis for co-routines

php-generator-as-coroutines.php

<?php

function getNextProduct($q, callable $f) {

    $qptr = 0;
    while (true) {
        if ($qptr == count($q)) {
            $qptr = 0;
        }

        yield $q[$qptr++];

        $f($q);
    }
     
}


function appendItemToQueue(array &$queue) {
    $item = 'SKU' . rand(0,9999);
    echo __METHOD__ . ": Adding item to queue: $item \n";
    $queue[] = $item;
}



$queue = array('GM24ER', 'GM2CZ3', 'CMIROR1', 'CCIOP.1','KVL1234');
foreach (getNextProduct($queue, appendItemToQueue)  as $sku) {
    echo "Processing sku: ${sku} \n";
    sleep(1);
}



------ Sample Run ---

shell> php queue-using-generator.php 
Processing sku: GM24ER 
appendItemToQueue: Adding item to queue: SKU8989 
Processing sku: GM2CZ3 
appendItemToQueue: Adding item to queue: SKU6431 
Processing sku: CMIROR1 
appendItemToQueue: Adding item to queue: SKU871 
Processing sku: CCIOP.1 
appendItemToQueue: Adding item to queue: SKU9266 
Processing sku: KVL1234 
appendItemToQueue: Adding item to queue: SKU3339 
Processing sku: SKU8989 
appendItemToQueue: Adding item to queue: SKU1803 
Processing sku: SKU6431 
appendItemToQueue: Adding item to queue: SKU8395 
Processing sku: SKU871 
appendItemToQueue: Adding item to queue: SKU1185 
Processing sku: SKU9266 
appendItemToQueue: Adding item to queue: SKU6602 
Processing sku: SKU3339 
appendItemToQueue: Adding item to queue: SKU697 
Processing sku: SKU1803 
appendItemToQueue: Adding item to queue: SKU3269 
Processing sku: SKU8395 
^C