On Saturday, 23 November 2019 at 13:17:49 UTC, mipri wrote:
I read your question as "can I have typeclasses in D?"
I guess you could interpret it that way.
I think you knowing Rust at all might be clouding your vision, actually.
I have hardly ever ran the Rust compiler outside of the online one... so not very likely. Though I am keeping an eye on what they are working on with traits and generic programming and what is coming look promising and clean, but still incomplete in the compiler. But yeah, Rust is getting better in the generic department.
These might appear in completely different modules with their own unrelated code, written by other people, at a later time, and with this instance declaration, when the whole program is compiled together, some integers or the 'world' abstract type might be handled by a lot of code that only knows that it can call some name() function to get a string. This code did not need to be edited to add a 'world' case to a switch to provide this functionality.
Yes, the basic idea is to be able to specify all the behaviour for a full program without making any assumptions about binary representation, then at a later stage choose concrete types that can be swapped out freely without having any effect on correctness. That would be the ideal extreme case...
So you can easily switch between many different actual concrete implementations, debug-features, hardware types etc.
You basically write your program using concepts such as SetLike, StringLike, ArrayLike and so on, then worry about how they should be composed with concrete representations later.
in a timely manner. Here's a hack, instead: Typeclass declaration? There isn't one.
That might be a bit problematic? The goal is to have strong typing support from the compiler.
I'm sure that someone better at D could make enormous improvements on this though, with non-intrusive type registration and typeclass declarations that you can reflect on, etc.
Thanks for sharing your ideas on how to do typeclasses, I think you are onto something here.
I will probably resort to parameterising a struct as SetLike with a ConcreteSet as the parameter and then find some way to do matching as a start. I guess alias this can be used to "emulate" the super type binding. But it isn't quite clear to me how to best do it in D (or C++) yet.
