Twig operator to access class constants

Const operator # let you access class constants through any object of that class.

<?php
    class Message {
        const TYPE_INFO = "INFO";
        // ...
    }
    $msg = new Message();

{{ msg # TYPE_INFO }}
{# prints 'INFO' #}

{% if msg.type == msg#TYPE_INFO %}
    ...
{% endif %}

Note that due to Twig limitations, you must add brackets when using filters and selection operators on constants. (But you don't need to add it with other operators.)

    {{ (msg#TYPE_INFO)|upper }}
    {{ (msg#TYPE_INFO)[2] }}
    {{ (msg#TYPE_INFO).attr }}
    {{ msg#TYPE_INFO ~ 'S' }}

Install via Composer:

composer require dpolac/twig-const

Add the extension to Twig:

$twig->addExtension(new \DPolac\TwigConst\ConstExtension());

... or if you use Symfony, add the following to your services.yml config file:

services:
    # ...
    dpolac.twig_const.extension:
        class: DPolac\TwigConst\ConstExtension
        tags: [ { name: twig.extension } ]

To use another operator instead of default #, pass it as string to extension constructor.

Example:

$twig->addExtension(new \DPolac\TwigConst\ConstExtension('const'));
$twig->addExtension(new \DPolac\TwigConst\ConstExtension('::'));

{{ msg const TYPE_ERROR }}
{{ msg::TYPE_ERROR }}