smuuf/primi

<?php

declare(strict_types=1);

namespace Smuuf\Primi\Handlers\Kinds;

use \Smuuf\Primi\Context;
use \Smuuf\Primi\Ex\RuntimeError;
use \Smuuf\Primi\Ex\BreakException;
use \Smuuf\Primi\Ex\ContinueException;
use \Smuuf\Primi\Handlers\SimpleHandler;
use \Smuuf\Primi\Handlers\HandlerFactory;
use \Smuuf\Primi\Structures\AssignmentTargets;

/**
 * Node fields:
 * left: A source iterator.
 * item: Variable name to store the single item in.
 * right: Node representing contents of code to execute while iterating the iterator structure.
 */
class ForStatement extends SimpleHandler {

    protected static function handle(array $node, Context $context) {

        // Execute the left-hand node and get its return value.
        $subject = HandlerFactory::runNode($node['left'], $context);

        $iter = $subject->getIterator();
        if ($iter === \null) {
            throw new RuntimeError(
                \sprintf("Cannot iterate over '%s'", $subject->getTypeName())
            );
        }

        /** @var AssignmentTargets */
        $targets = HandlerFactory::runNode($node['targets'], $context);
        $blockHandler = HandlerFactory::getFor($node['right']['name']);

        // 1-bit value for ticking task queue once per two iterations.
        $tickBit = 0;
        $queue = $context->getTaskQueue();

        foreach ($iter as $i) {

            // Switch the bit from 1/0 or vice versa.
            if ($tickBit ^= 1) {
                $queue->tick();
            }

            $targets->assign($i, $context);

            try {

                $blockHandler::run($node['right'], $context);
                if ($context->hasRetval()) {
                    return;
                }

            } catch (ContinueException $e) {
                continue;
            } catch (BreakException $e) {
                break;
            }

        }

        $context->getTaskQueue()->tick();

    }

}