[idbfs]

A paper that changed my approach to designing state machines is "Statecharts: A Visual Formalism for Complex Systems" by Harel (http://www.wisdom.weizmann.ac.il/~harel/papers/Statecharts.p...).

Statecharts (also called hierarchical state machines) are essentially generalized state machines which allow for nesting and parallel composition of states. The 'nesting' part is my favourite, since it allows one to delegate event handling logic shared by multiple states to a 'parent' state, reducing code duplication.

The great thing about this paper is that you can glean most of its key ideas by just looking at the diagrams.

[nickpsecurity]

Exactly. UML looked like over-complicated crap when I saw it after reading on Statecharts and Yourdon. The latter are still in use on occasion in high-assurance with Tenix's Dats Diode being an example.

[vanderZwan]

Funny how most visual programming languages (for example, puredata) look like these diagrams.