XML enables nested error handling

I am against using XML for following reason:

Checking the email policy is a process and for that we need a programming
language. SPF v1 is a programming language which can be directly processed
from left to right. It can be extended if required. Also nesting could be
possible with "begin" and "end" statements.

Whereas XML is a language that assigns attributes to data. If you use XML,
you first have to convert it to a program (by using some programming
language) before you can use it.

Roger