> In the absence of proper language support, “sum types” are just structs with discipline.

With enough compiler support they could be more than that. For example, I submitted a tagged union analysis feature request to gcc and clang, and someone generalized it into a guard builtin.

https://github.com/llvm/llvm-project/issues/74205

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112840

GCC proved to be too complex for me to hack this in though. To this day I'm hoping someone better than me will implement it.

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nine_k 5 hours ago | parent [-]

With proper discipline, one can even program a Turing machine directly. The problems are two: (1) Doing so is very slow and arduous, and (2) a chance of making a dangerous error is still quite high.

For instance, it appears that no amount of proper discipline, even in the best developers, allows to replace proper array support with a naked pointer to a memory area.

	▲	matheusmoreira 5 hours ago \| parent \| next [-]
		The compiler's job is to program the turing machine for us. It should help as much as possible. For example, I really like using enums because compilers have extensive support for checking that all values have been handled in switch statements. I don't like it when compilers start getting in the way though. We use C because we want to do raw things like point a structure at some memory area in order to access the data stored there. The compiler's job is to generate the expected code without screwing it up by "optimizing" it beyond recognition because of strict aliasing or some other nonsense.
	▲	convolvatron 4 hours ago \| parent \| prev [-]
		you can certainly wrap the array with a structure which provides either bounds information to be checked with generic runtime functions, or specific function pointers (methods) to get and set. you can paper over _alot_ of Cs faults. ultimately its not really worth it, but its not nearly as fragile and arduous as you make it out to be