Why are some types from std not in the core of the language?

[mesni]

On Friday, 10 June 2022 at 01:08:02 UTC, mesni wrote:
> D has AA and arrays built into the language and runtime. But 
> why are sumtype, arrays/smart pointers using custom allocators, 
> nullable, tuple at the expense of std? Everything listed in 
> this article https://dlang.org/articles/builtin.html applies to 
> them. I think this can be done as something like an optional 
> extension in the compiler.

By the way, all modern system languages ​​(zig, odin) have such 
types built in. And D, due to the need to maintain compatibility 
(although it still breaks it), moves away from the roots and 
follows the path of C++