I am thinking about giving a talk about regexes at my local Gophers (i.e. Go-hackers) meetup.

While the talk will mainly be about different regex-engines in Go, I would like to include some introductory material about regexes (what are they, what can I do with them) for which I am at the moment too lazy to create from scratch.

So my question is: Is there any material out there that explains what regexes are in a language-agnostic way that I could use?

And just to assure you: My talk will be a shameless plug about the virtues of the perl-ecosystem by extolling the virtues of using Regexp::Common to generate regexes that go directly into the Go-enine (thanks haukex by the way).

Many thanks!