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No because in Rust and C++ using smart pointers is an explicit choice that is applied manually when required and is present both in the type signature everywher

No because in Rust and C++ using smart pointers is an explicit choice that is applied manually when required and is present both in the type signature everywhere a reference counted type is used, and in the construction of values. In Swift the reference counting is a implementation detail of automatic and transparent memory management. (that you only really have to care about when you have cycles) That's why Swift definitely counts as a GC language for me. Sure, if you put things behind a Arc<T> or shared_ptr you use reference counting in C++ and Rust, but it is not an inherent feature of the language.

chobytes 8y ago
ARC only applies to reference types. The programmer has acess to value types, and manual memory management if they want it.
0815test 8y ago
In Rust, using smart pointers is not much of an "explicit choice" - it's simply the idiomatic thing to do when something might be kept around by more than one parent object. Rc<T> basically means that there are multiple sources of control over T's lifetime, but these are all within a single thread; and Arc<T> signals that the control might extend to multiple threads. It's not "mere implementation" that we're dealing with here; it's the very semantics of the code as it relates to Rust's expanded take on the well-known RAII pattern. Swift simply lacks an equivalent to either the Rc<> specifier or e.g. Rust's Box<>, which expresses the semantics of an object which is heap-allocated and accessed via an indirection, and verifiably has at all times a unique "owner" controlling its lifetime (as per usual RAII).
- steveklabnik 8y ago
  You can argue it’s an explicit choice because you can often choose to structure your code in a way that doesn’t require Rc. Of course, it exists because sometimes, you do have to or want to, but those cases are pretty rare in my experience.

chobytes 8y ago

ARC only applies to reference types. The programmer has acess to value types, and manual memory management if they want it.

0815test 8y ago

In Rust, using smart pointers is not much of an "explicit choice" - it's simply the idiomatic thing to do when something might be kept around by more than one parent object. Rc<T> basically means that there are multiple sources of control over T's lifetime, but these are all within a single thread; and Arc<T> signals that the control might extend to multiple threads. It's not "mere implementation" that we're dealing with here; it's the very semantics of the code as it relates to Rust's expanded take on the well-known RAII pattern. Swift simply lacks an equivalent to either the Rc<> specifier or e.g. Rust's Box<>, which expresses the semantics of an object which is heap-allocated and accessed via an indirection, and verifiably has at all times a unique "owner" controlling its lifetime (as per usual RAII).

steveklabnik 8y ago
You can argue it’s an explicit choice because you can often choose to structure your code in a way that doesn’t require Rc. Of course, it exists because sometimes, you do have to or want to, but those cases are pretty rare in my experience.