Comment by jstimpfle | Hacker News Reader

Comment by jstimpfle | Hacker News Reader

Parent Full thread

> The truth here is that you might want a lot of different operations and the C choice is not only to provide a single choice, which made a lot more sense 50+ years ago than it does today, but to provide a singularly bad default.

C has a single '+' operator, just like Rust has. And what that operator does depends on the types to the left and to the right. You can cast between integer types to achieve different behaviours depending on what you want.

About u8::unchecked_sub() etc, those are just regular functions. Not really a language thing. Yes, nothing of that is standardized in C AFAIK, but I'll happily use e.g. __builtin_add_overflow() or whatever in practice.

We can argue all day long what are the right defaults, checked or unchecked operations. If you want to be safe, you want the compiler to emit checks. It's probably possible to get some of those in GCC. If you want to emit streamlined machine code, you'll definitely not want to add checks after every machine instruction.

> About u8::unchecked_sub() etc, those are just regular functions. Not really a language thing. Yes, nothing of that is standardized in C

Well "regular functions" in the sense that these are methods of the primitive type u8†, and of course neither C nor C++ can do that at all. So, yeah, it's a language thing.

In C++ what you'd do here instead is invent custom types and add the methods you want to the types, and I would give C++ credit here if the stdlib provided say, a bunch-of-bits base type with all the bit-twiddling methods defined and maybe specialisations for the 32-bit and 8-bit unsigned integers or something, but AFAICT it doesn't do anything like that.

"I could go out of my way to do this" is true for everything in any of the general purpose languages by their nature.

† In Rust if we define a function associated to a type T with a "self" first parameter then you can call that function as just a method on any value of type T and the appropriate parameter is inferred. So e.g. u8::checked_sub(u8::MAX, 10) is Some(245) but u8::MAX.checked_sub(10) is also Some(245) because it de-sugars to the same call.

__builtin_add_overflow() is type-generic as well, what is the big difference to this Rust stuff? I'd say Rust is more ergonomic here (standardized calls, I don't have to resort to GCC builtins). But it's not fundamentally different in capabilities.

I really don't care about functions vs methods, what is the difference, it's just syntax. Actually, keeping to regular function calls is mostly more readable to me, compared to using methods, using short unqualified method names, mixing function calls and methods calls, nesting/chaining functions and methods.

Sure, other than the ergonomics it's the same. But, other than the ergonomics Fortran and C# are the same so what are we even talking about ?

Better ergonomics means it's more likely the programmer writes what they actually meant, and if you do that modern compilers have got better at making what you meant fast even as they remain the same or perhaps slightly worse at converting vague gestures which aren't clear about what you meant into what you had hoped for without expressing it.

Reply on news.ycombinator.com