Comment by codebje

You could probably say that. AFAIK there isn't a single valid definition of a dependently typed language any more than there is a single valid definition of a functional language.

I usually go with "you can make a dependent pair", which is two terms where the type of the second depends on the value of the first; I think you could do that in Zig with a bit of handwaving around whether the comptime expression really is the first value or not.

What Zig's doing is also, as best I understand it all, the only real path to anything like dependent types in imperative languages: make a separate sub-language for constant expressions that has its own evaluation rules that run at compile time. See also C++ constexpr, or the constants permitted in a Rust static array size parameter (practically a dependent type itself!)

A functional language's basic building block is an expression and terms are built out of composed expressions; normalisation means reducing a term as far as possible, and equality is (handwaving!) when two terms reduce to exactly the same thing. So you can do your dependent terms in the usual source language with the usual evaluation rules, and those terms are freely usable at runtime or compile time, it's all the same code.

An imperative language's basic building block is a memory peek or poke, with programs composed of sequences of peeks and pokes scheduled by control flow operators. It's much less clear what "normalisation" looks like here, so imperative languages need that separate constant-value embedded language.