I have an important metric for new "systems" languages: does the language allow NULL for it's commonly used pointer type. Rust by default does not (References may _not_ be NULL). Here is where I think Odin makes a mistake.
In the linked blog post Odin mentions ^os.File which means pointer to File (somewhat like *FILE in C). Theoretically the pointer can be NULL. In practice, maybe I would need to check for NULL or maybe I would not (I would have to scan the Odin function's documentation to see what the contract is).
In Rust, if a function returns &File or &mut File or Box<File> etc. I know that it will never be NULL.
So Odin repeats the famous "billion-dollar mistake" (Tony Hoare). Zig in comparison is bit more fussy about NULL in pointers so it wins my vote.
Currently this is my biggest complaint about Odin. While Odin packages a lot of power programming idioms (and feels a bit higher level and ergonomic than Zig) it makes the same mistake that Golang, C and others make regarding allowing NULL in the default pointer type.
MyObject can't be null. MyObject? can be null. Handling nullability as a special thing might help with the billion-dollar mistake without generating pressure to have a fully fleshed out ADT solution and everything downstream of that.
To people who would dismiss ADTs as a hard problem in terms of ergonomics: Rust makes it less miserable thanks to things like the question-mark shorthand and a bazillion trait methods. Languages like Haskell solve it with a monads + do syntax + operating overload galore. Languages like Scala _don't_ solve it for Result/Option in any fun way and thus are miserable on this point IMHO
Nullability is a good retro-fit, like Java's type erased generics, or the DSL technology to cram a reasonable short-distance network protocol onto the existing copper lines for telephones. But in the same way that you probably wouldn't start with type erased generics, or build a new city with copper telephone cables, nullability isn't worth it for a new language IMO.
It's interesting that effect system-ish ideas are in Zig and Odin as well. Odin has "context". There was a blog post saying it's basically for passing around a memory allocator (IIRC), which I think is a failure of imagination. Zig's new IO model is essentially pass around the IO implementation. Both capture some of the core ideas of effect systems, without the type system work that make effect systems extensible and more pleasant to use.
E.g. if you have a list finding function that returns X?, then if you give it a list of MyObject?, you don't know if you found a null element or if you found nothing.
It's still obviously way better than having all object types include the null value.
The two are not equal, and only the second one evaluates to true when compared to a naked nil.
fn find<T>(self: List<T>) -> (T, bool)
But exactly like Go's error handling via (fake) unnamed tuple, it's very much error-prone (and return value might contain absurd values like `(someInstanceOfT, false)`). So yeah, I also prefer language w/ ADT which solves it via sum-type rather than being stuck with product-type forever.
Maybe(T) would be for my own internal code. I would need to wrap/unwrap Maybe at all interfaces with external code.
In my view a huge value addition from plain C to Zig/Rust has been eliminating NULL pointer possibility in default pointer type. Odin makes the same mistake as Golang did. It's not excusable IMHO in such a new language.
Even ignoring the practical consequences, this means the programmer probably doesn't understand what their code does, because there are unstated assumptions all over the codebase because their type system doesn't do a good job of writing down what was meant. Almost might as well use B (which doesn't have types).
PS: I just read a funny comment on YT video: "Odin feels like a DSL for writing games masquerading as a systems language."
Zig doesn't have interfaces as a language level feature. It uses manually implemented vtables and wrapper methods.
You can do the same in Odin with wrapper functions around a vtable.
Once Jonathan Blow's Jai comes out next year, the language that inspired conception of both of these, Odin will likely have no chance competing on the marketing side of things with programmers and will be taken over by Jai, and Zig in a large extent as well. So the future of the language might not be as solid as it might seem and it might end up just as an internal tool for JangaFX, which is how it originated.
Having the "web stuff" can attract literally millions of developers whom can elevate the language into more stable and broadly used language. More documentation would become available, libraries, youtube videos, internet presence in general.
All procedures in core/os. Odin isn't removing the allocator from implicit context in the rest of its APIs.