Rust gives you FP-style without loads of copies and C-like performance. Immutable data-structures aren't idiomatic, but it's ownership gives you most of the same benefits.

The nice thing about Rust is that it gives you the main benefits of FP even when you're not programming in "FP style". The Rust "sharing xor mutability" default model provides underlying semantics and ease of analysis that's quite comparable to what you get with a pure-functional language. Of course extended mutability as with Cell<>, RefCell<> etc. undermines this, but these are only used when necessary.

And many string types, like Haskell /s