They were named "regular" in the formal sense. Thus if they are not regular, it is a misnomer. It would have been just as useful to call them "Perl Matching Exp

They were named "regular" in the formal sense. Thus if they are not regular, it is a misnomer. It would have been just as useful to call them "Perl Matching Expressions", but without all the additional confusion about what a regular expression can do.