<?php

$array['order_details']['date'] = '01/02/03';
$array['name'] = 'blah';
$array['order_details']['total'] = '300';

$email = '

-- Order Details: -- 
Date: {%order_details_date}
Total: {%order_details_total}

Thanks {%name}!

';


function ParseArray($array,$email,$parentkey='') {
	foreach($array as $key => $value) {
		if(is_array($value)) {
			$email = ParseArray($value,$email,$key);
		} else {
			if($parentkey != '') {
				$var = $parentkey.'_'.$key;
			} else {
				$var = $key;
			}
			$email = str_replace("{%$var}",$value,$email);
		}
	}
	return $email;	
}

echo ParseArray($array,$email);