Now that what it is is clearer to me, the amazing thing about it is actually Perl. The fact that you can chain the three stages together like that without the rigidity of traditional list based languages is really nice.

On a related note, I know that you can chain the word "and" 5 times in a row in a gramatically correct English sentance - what's the most number of "is"s that people can chain together? I can do 3.

Yes I know it's not really related, but I can never write a sentance with "is is" without then wondering :)