Simple Twig extension that provides a new function and filter for templates, {{ get_some_html() }} {{ 5500|price }}

gistfile1.txt

<?php

namespace S2\MyFancyBundle\Templating;

use Symfony\Component\DependencyInjection\ContainerInterface;

class MyHtmlExtension extends \Twig_Extension
{
    private $aFancyService;

    public function __construct($aFancyService)
    {
        $this->aFancyService= $aFancyService;
    }

    public function getFunctions()
    {
        return array(
            'get_some_html' => new \Twig_Function_Method($this, 'getSomeHtml', array('is_safe' => array('html'))),
        );
    }

    public function getFilters()
    {
        return array(
            'price' => new \Twig_Filter_Method($this, 'priceFilter'),
        );
    }

    public function getSomeHtml()
    {
        return $this->aFancyService->getTheHtml();
    }

    public function priceFilter($number, $decimals = 0, $decPoint = '.', $thousandsSep = ',')
    {
        $price = number_format($number, $decimals, $decPoint, $thousandsSep);
        $price = '$' . $price;

        return $price;
    }

    public function getName()
    {
        return 'a_fancy_name';
    }
}

Sample YML definition (minus the "aFancyService" injection that you'd need if you had a fancy service to inject):

services:
    myhtml.twig.extension:
        class: S2\MyFancyBundle\Templating\MyHtmlExtension
        tags:
            -  { name: twig.extension }

Sample XML definition (minus the "aFancyService" injection that you'd need if you had a fancy service to inject):

<service id="myhtml.twig.extension" class="S2\MyFancyBundle\Templating\MyHtmlExtension">
    <tag name="twig.extension" />
</service>