is_email should be RFC complient

[jorbin]

#blamenacin

I like this alot.

Duplicate of #4616

Viewing that regex will insert a malicious easter egg in your brain.

There are alot of slashes in that patch. Can we use less? They are a natural resource after all.

Willing to commit this if you can produce 100% unit test coverage. I'll wait.

This patch has one main flaw and that is the lack of a capital P I think it needs-improvement

Hmm, looks like that one parenthesis is out of place...

If we wait until 3.2 with PHP 5.x, we can just do

filter_var( $email, FILTER_VALIDATE_EMAIL ) instead, right?

Replying to filosofo:

If we wait until 3.2 with PHP 5.x, we can just do

filter_var( $email, FILTER_VALIDATE_EMAIL ) instead, right?

Probably not. Those can be buggy. We could potentially leverage it internally but we need to watch out for vulnerabilities and what not across PHP versions.