A PHP implementation to parse django template vars

django_vars.php

<?php

/*

Sergio Álvarez Muñoz
xergio@gmail.com
https://sergio.am

Basado en el sistema de templates de Django.
Snipper adaptado de http://effbot.org/zone/django-simple-template.htm

*/

define("TEMPLATE_STRING_IF_INVALID", "");


function render($template, $context) {
	$tokens = preg_split("#({{|}})#", $template, -1, PREG_SPLIT_DELIM_CAPTURE);
	$data = array();
	$jump = 0;

	foreach ($tokens as $i => $token) {
		if ($jump-- > 0) continue;

		if ($token == "{{") { # variable
			$data[] = variable($tokens[$i+1], $context);
			if ($tokens[$i+2] != "}}")
				throw new Exception("missing variable terminator");
			$jump = 2;

		} else {
			$data[] = $token; # literal
		}
	}
	return implode("", $data);
}


function variable($name, $context) {
	$name = trim($name);
	$obj = $context;

	if (strpos($name, "|") !== false)
		list($name, $filters) = explode("|", $name, 2);
	
	foreach (explode(".", $name) as $item) {
		if (is_array($obj) and array_key_exists($item, $obj)) {
			$obj = $obj[$item]; # dictionary member

		} else if (is_object($obj)) {
			if (property_exists($obj, $item)) {
				$obj = $obj->$item; # or attribute

			} else if (method_exists($obj, $item)) {
				$obj = $obj->$item();
			}

		} else {
			$obj = TEMPLATE_STRING_IF_INVALID;
			break;
		}
	}
	if (isset($filters)) {
		if (function_exists($filters)) {
			$obj = call_user_func($filters, $obj);
		}
	}
	return $obj;
}



$test = <<<TEST
<h1>{{ section.title }}</h1>

<h2>
  <a href="{{ story.get_absolute_url }}">
	{{ story.headline|strtoupper }}
  </a>
</h2>
<p>{{ story.tease|truncatewords:"100" }}</p>
TEST;

class FakeSection {
	public $title = "trololo";
}
class FakeStory {
	function __construct($headline, $tease) {
		$this->headline = $headline;
		$this->tease = $tease;
	}
	function get_absolute_url() {
		return "Absolute/Url";
	}
}

$input = array(
	"section" => new FakeSection(),
	"story" => new FakeStory("Headline!", "Tease... brrrr")
);

print_r(render($test, $input));