It's not a FP language, but it's clearly heavily influenced by FP.
Mutability is a significant part of Rust, but it's much more sharply curtailed than any non-FP language I've ever seen. To be allowed to mutate something, you have to prove that nothing else holds a reference to it. That means that any code that doesn't use mutability itself can pretend that mutability doesn't exist.
Mutability is a significant part of Rust, but it's much more sharply curtailed than any non-FP language I've ever seen. To be allowed to mutate something, you have to prove that nothing else holds a reference to it. That means that any code that doesn't use mutability itself can pretend that mutability doesn't exist.