Look what I found

@error @brunoph I think I remember techniques like this were useful for faking multithreading to do things like background calculations.

I was not smart enough or too smart to do it this way.

@error Duff's device all over again. Nice!

@error /me sets mode = 3, chuckling

@_the_cloud Yeah, but if you click the link, they actually use default case there.

@error I'm calling the police

@error that's wild. I wonder how this would be treated by different formatters/style enforcers and if it would break

@error At the time this was written (for hardware & compilers were pre SSA) this could have been reasonable.

@error yup that's how Contiki implemented Protothreads initially:

https://dunkels.com/adam/pt/

@error That's super neat, I didn't know! I'll probably use this in my code at a some point...

@error this should be classified as an infohazard

@error

Three lines too many. I thought serious programmers were lazy.

@error It's an utter pain in the arse when writing a compiler too, and even worse is when goto gets involved.

@mikee I actually tried it. It works just fine to my surprise. But the clangd formatter gone mad:

@error @_the_cloud Only in the original example, not in the first two. I'd set it to 3 and chuckle too. I'm an FPGA guy, so I always think about else/default.

@error gloop, arfle, barfle says it all.

@error ha! Thanks for testing!

@error it's beautiful

@error reminds me of Duff's Device for abitrary length byte copy using the switch as an index into an architecture-appropriate unrolled loop https://en.wikipedia.org/wiki/Duff%27s_device

@vaporeon_ please don't

@error I don't think I ever would have tried to pass that off, myself, but I sort of admire the fact that, even though it's language abuse, it produces a predictable outcome. C has a lot of undefined behavior, but somehow, this isn't.

I think I tried to use Duff's Device in a project once, but my colleagues objected and made me change it. Or maybe I just explained Duff's Device to them and they were horrified. Like, "I don't know if I can trust that guy anymore" horrified. It was a long time ago.

This is interesting but it's not really saving a ton of time or code space. I think Duff's Device is probably more defensible.