If you agree with the notion that you need to be able to tell the difference between the absence of a value and a value itself, then this has some impacts on the code you write. If you want to keep ’em separated (so they can come out and play), then it gets you looking at your API designs in certain ways.

These are my reactions to some of the ways a value can be returned (or not).

Before you head off to read Rachel’s post, allow me to close the loop on that Offspring reference for those of us who didn’t grow up in the 90’s.