Just read the Design by Contract article on Wikipedia… a good read!
You can convert an IP address to an int, and vice versa, with these two MySQL functions. Of course I learned about this after I’d already implemented IP address support using BINARY(4) and my own parser/formatter… now that I have my own implementation I can’t bring myself to let it go, and I worry about support for signed/unsigned 32-bit ints (perhaps my concerns are unfounded..?)
I was reminded today of the Ackermann function which is famous in computer science.
Today I added the Robots <META> tag with noindex, nofollow to my HTML error documents.