[gf000]

I don't think there is a standardized meaning of 'low-level'. I think a useful definition is that a low-level language controls more/is explicit about more properties of execution.

So zig/c/c++/rust all have ways to specify when and where should allocations happen, as well as memory layout of objects.

Expressivity is a completely different axis on which these low-level languages separate. C has ultra-low expressivity, you can barely create any meaningful abstraction there. Zig is much better at the price of remarkably small amount of extra language complexity. And c++ and rust have a huge amount of extra language complexity for the high expressivity they provide (given that they have to be expressive even on the low-level details makes e.g. rust more complex as a language than a similar, GC-d language would be, but this is a necessity).

As for this particular case, I don't really see a level difference here, both languages can express the same memory layout here.

[foltik]

It’s one specific low-level abstraction, which is well defined: the primitive building blocks a higher level abstraction is built on and oblivious to.

Zig’s comptime is the primitive. Sum types, generics, etc. are things you can build on top.

The original example is the type-level equivalent of looking at:

  int foo() {
    return 4;
  }

and saying “why do I need all this function and return ceremony when I can just write the number 4 verbatim?”