[sekao]

Agreed. Zig's approach re-uses the existing machinery of the language far more than C++ templates do. Another example of this is that Zig has almost no restrictions on what kinds of values can be `comptime` parameters. In C++, "non-type template parameters" are restricted to a small subset of types (integers, enums, and a few others). Rust's "const generics" are even more restrictive: only integers for now.

In Zig I can pass an entire struct instance full of config values as a single comptime parameter and thread it anywhere in my program. The big difference here is that when you treat compile-time programming as a "special" thing that is supported completely differently in the language, you need to add these features in a painfully piecemeal way. Whereas if it's just re-using the machinery already in place in your language, these restrictions don't exist and your users don't need to look up what values can be comptime values...they're just another kind of thing I pass to functions, so "of course" I can pass a struct instance.

[WalterBright]

> Zig has almost no restrictions on what kinds of values can be `comptime` parameters.

Neither does D. The main restriction is the CTFE needs to be pure. I.e. you cannot call the operating system in CTFE (this is a deliberate restriction, mainly to avoid clever malware).

CTFE isn't "special" in D, either. CTFE is triggered for any instance of a "constant expression" in the grammar, and doesn't require a keyword.