[sobellian]

IMO the pendulum swung too far with Rust. The experience is better than C++, but the template generics system is not very powerful. They ostensibly made up for this with macros, but (a) they're annoying to write and (b) they're really annoying to read. For these reasons Rust is much safer than C++ but has difficulty providing fluent interfaces like Eigen. There are libraries that try, but AFAICT none match Eigen's ability to eliminate unnecessary allocation for subexpressions and equivalently performing Rust code looks much more imperative.

[api]

Rust doesn't have a template system per se. C++'s templates are closer to C's macros. Rust has a typed generics system which does impose additional limits but also means everything is compile time checked in ways C++ isn't.

I agree that Rust's macros are annoying. I think it was a mistake to invent an entirely different language and syntax for it. Of course Rust also has procedural macros, which are macros written in Rust. IMHO that's how they should all work. Secondary languages explode cognitive load.

[sobellian]

I'm not attached to the word "template", I just wanted to clarify that they're not Java-style generics with type erasure. If you'd like me to use "monomorphizing generics" instead I'm game :)

Even procedural macros are annoying, though. You need to make a separate crate for them. You still need to write fully-qualified everything, even standard functions, for hygiene reasons. Proc macros that actually do, erm, macro operations and produce a lot of code cause Rust's language server to grind to a halt in my experience. You're effectively writing another language that happens to share a lexer with Rust (what's the problem with that? Well, if I'd known that I'd need another language to solve my problem I might not have chosen Rust...).

[pjmlp]

For all its warts, using constrexpr if and concepts, is much more easier to do macro like programming than dealing with Rust's two worlds of macros and special syntax.

If static reflection does indeed land on C++26, this experience will be even better.