One of the section headings says "Mutation vs. immutable monad is the core difference" but this is not true.
The code in that section is clear in its purpose and broad outline: "Give me a function and data; if the data is bare apply the function to it; if the data is a container apply the function to each item inside it."
You can absolutely do that with immutable data structures in Zig. You just have to pass an allocator to the function (i.e. instead of calling data.flat_map(f), you call data.flat_map(a, f) where a is your allocator).
That the Zig version of the code does mutation is a matter of programmer choice, not something imposed by the language.
So, what you're not seeing is that even though the Rust doesn't announce mutation the implementation may be mutation anyway if that's probably faster/ cheaper.
unsafe impl<I, U, F> InPlaceIterable for FlatMap<I, U, F> where
I: InPlaceIterable,
U: BoundedSize + IntoIterator,
What you're seeing is the graceful goose on the water moving forward at pace. Beneath there is frantic action to make that happen. The Rust surface was more a maintainable immutable operations, but the implementation is a frantic whirling mutation like the Zig.
In Zig you end up spending a lot of time writing How to do a thing, where in Rust you only wrote What the thing is and the machine did it. There are edge cases where Zig's explicitness wins for the best programmers, but there just aren't enough of those cases or those programmers for this to net out IMNSHO.
Or more of an opportunity cost. You are able to get to 100% performance with dedicated attention from skilled engineers. But otherwise normal gods just manage to get a bare 60% out, versus the 80% they would get in rust. (Numbers are fictional.)
csense · · focus · HN ↗
The code in that section is clear in its purpose and broad outline: "Give me a function and data; if the data is bare apply the function to it; if the data is a container apply the function to each item inside it."
You can absolutely do that with immutable data structures in Zig. You just have to pass an allocator to the function (i.e. instead of calling data.flat_map(f), you call data.flat_map(a, f) where a is your allocator).
That the Zig version of the code does mutation is a matter of programmer choice, not something imposed by the language.
(Also, what do monads have to do with it?)
tialaramex · · focus · HN ↗
In Zig you end up spending a lot of time writing How to do a thing, where in Rust you only wrote What the thing is and the machine did it. There are edge cases where Zig's explicitness wins for the best programmers, but there just aren't enough of those cases or those programmers for this to net out IMNSHO.
slopinthebag · · focus · HN ↗
spockz · · focus · HN ↗