<?php
    // Declare the interface 'iTemplate'
    interface iTemplate
    {
        public function setVariable($name, $var);
        public function getHtml($template);
    }

    /**
    Implement the interface
    This will work
     */
    class Template Implements iTemplate
    {
        private $vars = array();

        public function setVariable($name, $var)
        {
            $this-vars[$name] = $var;
        }

        public function getHtml($template)
        {
            foreach ($this->vars as $name => $value) {
                $template = str_replace('{'.$name.'}', $value, $template);
            }

            return  $template;
        }
    }

    /**
    This will not work
    Fatal eroor: Class BadTemplate contains 1 abstract methods
    and must therefore be declared abstract (iTemplate::getHtml)
     */
    class BadTemplate Implements iTemplate
    {
        private $vars = array();

        public function setVariable($name, $var)
        {
            $this->vars[$name] = $var;
        }
    }
?>