In case you are wondering about the What of Y (as I was). Here is a paragraph from the PDF:
"The point of Y is to provide a mechanism to write self-referential programs without a special built-in
means of accomplishing it. In Scheme there are several mechanisms for writing such programs,
including global function definitions and letrec. Here is one way to write the factorial function in
Scheme:..."
It's an article about the thing this website (and company) is named after. Hence it's probably the most meta-recursive link that ever gets posted on HN. (BTW Dick Gabriel is a Zen-Lisper and poet. Wise programmers read everything he writes.)
David X. Cohen, the Futurama executive producer who also holds an MS in computer science from UC Berkeley, wrote an episode called "The Why of Fry." It involved some time travel, which I always think of as self-referential.
I thought this was going to be about how Dijkstra stuck it to the Algol '68 Committee by introducing first order functions to the language after recursion support was rejected...
"The point of Y is to provide a mechanism to write self-referential programs without a special built-in means of accomplishing it. In Scheme there are several mechanisms for writing such programs, including global function definitions and letrec. Here is one way to write the factorial function in Scheme:..."