Earlier quoted context omitted.
> Rust has a perfectly nice type system by modern standards I disagree -- Rust's type system is pretty weak and very limiting compared to other modern languages like Typescript, Nim, Zig, or even C++. That's without even without getting into dependent type languages. There are so many basic patterns which Rust's type system can't handle, especially when it comes to compile time types. For example, one recent thing I…
> Personally I'm excited to see how C++ Concepts can evolve. So, C++ 20 Concepts is basically what Bjarne Stroustrup proposed for a future version of his C++ language in the early 2000s. Several people proposed and WG21 accepted, a far more capable feature set for Concepts, this is often referred to as C++ 0x Concepts, since it was accepted for C++ 0x, the standard that would eventually (after years of delays) become…
> C++ 0x Concepts was similar to Rust's Trait system in many ways. Particularly notable features of C++ 0x Concepts you might recognise in Rust's traits:
Perhaps at the loosest level of comparison around only defining limitations on possible types. However, C++ x0 concepts enable much more powerful combinations of logic to specify if a template fulfills a concept. In Nim the concept can be any arbitrary boolean statement.
This blog has some good examples of C++ concepts: https://www.sandordargo.com/blog/2021/03/10/write-your-own-c...
It's trivial to specify that a C++ concept can be either a float or an integer:
template
concept HasPower = (std::integral || std::floating_point) && requires (Base base, Exponent exponent) {
base.power(exponent);
};
> 1. Third parties can implement a C++ 0x Concept for some type which was not originally conceived with this Concept in mind, they just write the implementation and it works.
That's true for C++ concepts, but not entirely true for Rust traits. You can only implement a Rust trait if you own the type or own the trait. If you use two third party libraries, you cannot implement a trait from one for a type from the other. At best you can wrap the type in a new struct, and reimplement the parent's traits.
https://stackoverflow.com/questions/25413201/how-do-i-implem...
> 2. C++ 0x Concepts must be explicitly implemented they're not just a syntactic requirement that could be satisfied by happenstance in a type which is not in fact suitable.
That doesn't appear to match with C++ resources like: https://en.cppreference.com/w/cpp/language/constraints
Everything in Rust traits requires them to be encoded into existing traits. C++ concepts let you define rules for arbitrary combinations of types. So you can create functions that take two independent types and define a constraint on those types.