[codewright]

>+ the Maybe monad (kind of a degenerate case)

Hey. Hey. heyyyyy.

I've used bind + maybe monad 'ish stuff in Python to clean up code previously littered with redundant if checks.

[tikhonj]

He probably means its a degenerate case of the list monad. Which is a useful way to look at it: a Maybe value is like a list of length at most 1.

You can also look at it as a degenerate case of Either. (That is, Maybe a ~ Either () a.)

This is "degenerate" in the mathematical sense, much the same way you can think of a point as a degenerate circle.

[jerf]

Yes, the point is that it's just about the simplest Monad implementation that actually does something useful.

I'd observe in my code that I rarely have an enormous do block using Maybe; instead what I see a lot is use of the monadic interface to tie things together that would normally be a lot of if blocks, all on one line into one expression. You start missing that in other languages real fast. Also the Applicative instance is often quite useful, allowing you to easily tie together several things that return Maybes into a call of some sort that does the right thing if one of them is a Nothing, almost "free" from a syntax point of view.

[jneen]

Haha, yeah, I meant "degenerate" in the mathematical sense. Totally useful, but in explaining it you're going to get a lot of "well, it's trivial in this case because...", which isn't that helpful if you don't yet understand the underlying concepts :)