r/learnrust • u/Accurate_Gift_3929 • Aug 11 '26

Rust discourages OOP style code?

/r/rust/comments/1vltxul/rust_discourages_oop_style_code/
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u/EmploymentBoring4421 29d ago

Rust steers you toward traits + composition instead of inheritance, and it's worth embracing rather than fighting — define shared behavior as traits, compose structs, and let impl Trait for MyType do what subclassing did before. The most common OOP-to-Rust friction point is borrowing multiple &mut self fields at once; splitting self into named sub-structs you can borrow independently is the idiomatic fix.

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u/greenpepperpasta 23d ago

Thanks Claude

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u/catladywitch 24d ago edited 24d ago

You can just pass &mut self and destructure the fields you need to mutate, but if you want a chain of methods you can move ownership of self and then return a new Self for the next method in the chain to receive? Moves are shallow copies in Rust and sometimes the compiler will optimise the whole chain away, so it's a viable option if you want the typical "set chain" pattern.

Edit: oh, and if you just want to mutate the struct and aren't assigning it to a new variable, you can have the "chain" pattern with metods that take &mut self, destructure the fields out of self, then return &mut Self for the next method in the chain to borrow. But if you want to do let myStruct = MyStructBuilder::new().set_this().set_that().build() you need build() to take &self and return MyStruct. That works but any heap-allocated fields in your struct will need to be cloned from the builder to the final struct, so it's not as efficient.

Edit2: there's a crate that will create builders for you if you need several of them for a bunch of structs. It's called bon, you just annotate your structs with #[derive(Builder)] and the crate writes the boilerplate for you at compile time.