Why do C++ programmers are not interested in D?

[Ola Fosheim Grøstad]

On Tuesday, 19 November 2019 at 13:06:29 UTC, Mark wrote:
> In addition to what others have written, here's another thing 
> to consider: D's "killer feature" is its metaprogramming 
> capabilities, but I don't think most C++ programmers, rightly 
> or wrongly, care that much about metaprogramming.

I think library authors do, though. Anyway there are issues 
related to meta programming in C++, D, and Rust. But they all 
also improve on that for every significant version bump. Whoever 
stops evolving their metaprogramming features will fall behind.

Rust is getting const generics eventually and C++ has added many 
library features and some minor language tweaks. It would be a 
good idea for D to make some statements about what is coming on 
the metaprogramming front.

> I think the reason Rust hasn't replaced C++ (so far, anyway) is 
> similar - it's killer feature is "memory safety by default" but 
> most C++ programmers that I know don't consider (lack of) 
> memory safety to be a major problem in the language.

There are certain things in rust that is verbose in Rust and that 
would be annoying to many C++ programmers. E.g. if you don't want 
to initialise a variable then you have to wrap the type in 
MaybeUninit<T>, and then use mem::transmute<_,T>(variable) as a 
cast after the variable has been initialized.

This level of safe/unsafe type system verbosity is only ok if you 
almost always initialise variables.

I think the default mode for many C++ programmers is to not trust 
the optimiser to get it right. Which can be a liability, it 
really depends on whether you want a primarily low level language 
with some high level capabilities (C++) or a primarily high level 
language with some low level capabilities (D and Rust).