smuuf/primi

<?php

declare(strict_types=1);

namespace Smuuf\Primi\Handlers\Kinds;

use \Smuuf\Primi\Context;
use \Smuuf\Primi\Handlers\HandlerFactory;
use \Smuuf\Primi\Handlers\SimpleHandler;
use \Smuuf\Primi\Helpers\Func;

/**
 * This handler is used to access nested items or attributes and prepare it
 * for nested assignment.
 *
 * For example, this is a vector:
 * ```js
 * a[1].b['x'].c[0] = 'yes'
 * ```
 *
 * The code is saying that someone wants to:
 *
 * _Store 'yes' under index `0` of the value `c`, which is an attribute of value
 * stored in `b` under the key `x`, which itself is the value stored under
 * index `1` of the value `a`._
 *
 * We need to process this chunk of AST nodes and **return an insertion proxy**,
 * which can then be used for assignment in the `Assignment` handler.
 */
class VariableVector extends SimpleHandler {

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

        // Retrieve the original value.
        $value = HandlerFactory::runNode($node['core'], $context);

        // And handle the nesting according to the specified vector.
        foreach ($node['vector'] as $next) {
            $handler = HandlerFactory::getFor($next['name']);
            $value = $handler::chain($next, $context, $value);
        }

        return $value;

    }

    public static function reduce(array &$node): void {

        $node['vector'] = Func::ensure_indexed($node['vector']);

        // Mark the last vector node as leaf, so it knows that we expect
        // insertion proxy from it.
        $first = \true;
        for ($i = \count($node['vector']); $i !== 0; $i--) {
            $node['vector'][$i - 1]['leaf'] = $first;
            $first = \false;
        }

    }

}