It's appositival, if it's there. And it doesn't have to be there. And it's really obvious that it's there when it's there.
Larry WallTake Lisp, you know its the most beautiful language in the world -- at least up until Haskell came along.
Larry WallSo many computer languages try to force you into one way of thinking and Perl is very much the opposite of that approach. It's kind of like a, well, sometimes Perl has been called the Swiss army chainsaw of the internet, but it's more like a Swiss army machine shop. It really gives you a lot of tools, some of which are dangerous, but it lets you get your job done very quickly.
Larry Wall