I’ve not looked much into D, but I’ve really been enjoying Rust.
I think the main takeaway is that there are very different ways of approaching language design. In Rust there was a decision to make the function signature the single place which defines the guaranteed input and output types to a function, but that is a trade-off. It encourages a more complex type system, as the flexibility of functions is on a sense constrained by the type system. Personally I like that explicitness, since there is only one place to look. In the future features like const generics and GATs will make that more powerful.
But on the other hand, D appears to be able to support much more complex types (possibly dependent types?) by not requiring that the type system can express them directly. In a sense the whole language can be used to define types. That’s a cool thing to be able to do, even if it means having to inspect documentation and method bodies to work out what they do.
I think the main takeaway is that there are very different ways of approaching language design. In Rust there was a decision to make the function signature the single place which defines the guaranteed input and output types to a function, but that is a trade-off. It encourages a more complex type system, as the flexibility of functions is on a sense constrained by the type system. Personally I like that explicitness, since there is only one place to look. In the future features like const generics and GATs will make that more powerful.
But on the other hand, D appears to be able to support much more complex types (possibly dependent types?) by not requiring that the type system can express them directly. In a sense the whole language can be used to define types. That’s a cool thing to be able to do, even if it means having to inspect documentation and method bodies to work out what they do.