Why bother replying to a worst nodes champion?

Please inform yourself about Dunning–Kruger effect before feeding a Ig Nobel prize contender. ;-p

> a) a subset of the perl language which addresses some domain,

Actually if you mean something like the RegEx engine I'd say it's external.

Anyway the definition is from the author I mentioned in the OP (Martin Fowler), and might be fuzzy at times.

> b) a perlish way to write some DSL code.

Yes, my main interest are DSLs which are implemented using Perl vocabulary and syntactic sugar.