Command-line script to process YAML frontmatter with Twig templates.

twig.php

<?php
/**
 * twig.php
 * 
 * Command-line script to process YAML frontmatter with Twig templates.
 * Inspired by Mustache <http://github.com/defunkt/mustache>.
 * 
 * Example template file (test.html):
 *   ---
 *   people: [ {name: scott}, {name: laura} ]
 *   ---
 *   {% for person in people %}
 *   	Hi {{ person.name }}!
 *   {% endfor %}
 * 
 * Usage:
 *   cat test.html | php twig.php
 * 
 * Or use "cat" to concatenate separate files together.
 * 
 * Example YAML file (test.yml):
 *   ---
 *   people: [ {name: scott}, {name: laura} ]
 *   ---
 *   
 * Example template file (test.html):
 *   {% for person in people %}
 *   	Hi {{ person.name }}!
 *   {% endfor %}
 *   
 * Usage:
 *   cat test.yml test.html | php twig.php
 * 
 */
require_once 'sfYaml.php';
require_once 'Twig/Autoloader.php';
Twig_Autoloader::register();

$text = array_map('trim', file('php://stdin'));
$edges = array_keys($text, '---');

if (count($edges) < 2) {
	echo "YAML frontmatter must start and end with '---'. Example:\n";
	echo "---\n";
	echo "name: John\n";
	echo "---\n";
	echo "\n";
	exit(1);
}

$last_edge = end($edges);
$frontmatters = array();

for ($i=0; $i < count($edges)-1; $i++) {
	$frontmatters[] = implode("\n", array_slice($text, $edges[$i] + 1, ($edges[$i+1] - $edges[$i] - 1))) . "\n";
}

$template_text = implode("\n", array_slice($text, $last_edge + 1)) . "\n";

$loader = new Twig_Loader_String();
$twig = new Twig_Environment($loader);

foreach ($frontmatters as $frontmatter) {
	$template = $twig->loadTemplate($template_text);
	$data = sfYaml::load($frontmatter);
	if (empty($data)) {
		continue;
	}
	$template->display($data);
}