[jhgb]

I'm pretty sure the "comptime" keyword only forces you to provide an argument constant at compile time for that particular parameter. It doesn't trigger the compile time evaluation.

[WalterBright]

That's how the constant is provided - through compile time evaluation.

[jhgb]

Yes, but compile-time evaluation in Zig doesn't require the "comptime" keyword. Only specific cases such as compile-time type computation do (but these specific cases are not provided by compile-time function evaluation in D anyway, so language choice wouldn't make a difference here).