<?php

class Klein {
    static function render($html, $vars) {
        $data = file_get_contents($html);
        $pattern = array(
            "/{%\s*for\s+(\w+)\s+in\s+(\w+)\s*%}/" => "<?php foreach(\$$2 as \$$1): ?>",
            "/{%\s*if\s+(\w+)\s*%}/" => "<?php if(isset(\$$1)): ?>",
            "/{%\s*block\s+(\w+)\s*%}/" => "<?php function $1() { ?>",
            "/{%\s*endblock\s*%}/" => "<?php } ?>",
            "/{%\s*endfor\s*%}/" => "<?php endforeach; ?>",
            "/{%\s*endif\s*%}/" => "<?php endif; ?>",
            "/{{\s*(\w+)\s*}}/" => "<?php echo \$$1; ?>",
        );
    
        $result = $data;
        foreach($pattern as $key => $value) {
            $result = preg_replace($key, $value, $result);
        }
    
        extract($vars);
        
        ob_start();
        eval(" ?>".$result."<?php ");
        return ob_get_clean();
    }
}