replace_template_strings.php

<?php

function replace_template_strings($template, $data = array(), $beginning_regex = '\{\{', $end_regex = '\}\}') {
  return preg_replace_callback('/' . $beginning_regex . '(\w+)' . $end_regex . '/', function($match) use ($data) {
    return empty($data[$match[1]]) ? "" : $data[$match[1]];
  }, $template);
}

usage.php

<?php
require("replace_template_strings.php");

$template = <<<TEMPLATE
Hello {{firstname}}, {{lastname}}!
TEMPLATE;

$data = array(
  "firstname" => "John",
  "lastname" => "Smith"
);

echo replace_template_strings($template, $data) . "\n";
// => Hello John, Smith!

This is very

very useful.