Why Developers Never Use State Machines (2011)

I use them extensively for Appointment Reminder. In addition to modeling the business logic pretty intuitively (particular types of input can cause an appointment to go from :scheduled to :confirmed, :confirmed appointments should not generate additional reminder calls but :scheduled ones should, etc), they're virtually indispensable for doing Twilio applications. I'll have more to say about that at TwilioConf (and will probably post my presentation afterwards). If you do not model call state with a state machine…

I've used state machines in the context of hardware design, particularly fpgas and asics. In hardware land, you use a state machine to implement something like software, where your circuit is able to remember what happened earlier so it can behave differently accordingly. It's very crude relative to their software counterparts. They are not as common in software because software is one giant state machine already. Variables hold state, there is state within state (classes, composition etc). Sometimes entities in…

> We Don’t Need One Until We Do Exactly that. In my career, I had to use a SM only once, but I really don't know how I could avoid it. The final code was a bit difficult to follow (PHP without Goto), but I drew an ASCII-art comment representing the state machine. And, it was perfectly fine. Fortunately, it was a "write only once" kind of business logic function.

I have used the state machine abstraction several times throughout the years. Specifically, I used them to replace regular expressions.