That's neither here, nor there. There are things like AST, various Lisps, etc. It's in the same realm as XSLT, you're not going to go as far as not calling it a programming language, are you?

With a proper IDE support it's no harder to write than Lisp. So by that definition

> EMC XProc Designer cannot translate graphical representation to code and vice versa.

the answer is yes, it can.

But the most popular tool in this category probably was Yahoo Pipes. They closed Yahoo Pipes.