monoids

Scott Wlaschin demystifies functional programming terms like monads, monoids, functors and catamorphisms by showing how they fit into a small toolkit. He applies them to problems such as missing data, list handling, and functional dependency injection.

Microsoft's Brian Beckman gives an hour-long, whiteboard-style walk through monads, building from function composition and monoids using school-level math. It is aimed at practicing programmers rather than category theorists.