Perl is a messy, maddening programming language, the “duct tape of the internet.” But at least you can tell it was made by humans.

Let me get this out of the way up front: Perl isn’t a beautiful language. It’s kind of a mongrel pup with pedigreed academic roots: C, AWK, Lisp, Pascal, sed, and a bit of Smalltalk and C++ ...

To see how associative arrays work, we’re going to look at both the Korn shell and Perl, though only the newest version of the Korn shell (referred to as “korn93”) supports associative arrays.

After reading I became curious as to why Perl and other languages features regular expression don't use the Thompson NFA approach. Can someone out there enlighten me?