Have you ever heard of an XY problem? It is when someone asks how to do Y when they really want to do X. They ask how to do Y because they believe it is the best way to accomplish X. The people that they ask go through many iterations of "try this", followed by "that won't work because of". I am not suggesting to use something other than Email::Valid
if that truly is
what is desired. What I am saying that is depending on the circumstance, other solutions may be the way to go.
For instance, say the problem is receiving spam messages from addresses that include % symbols and @ signs. You believe that it isn't a valid email address since you have never seen it before. You use Email::Valid and you find out that it is very valid and is a common trick for open-relays. Hmmmm - what do I do? You create your own regex that says I do not care if this is valid, no legitimate mail I receive uses this syntax so I am going to get rid of it.
Cheers - L~R