Fonctions externes
Rust supports generics, which lets you abstract algorithms or data structures (such as sorting or a binary tree) over the types used or stored.
/// Pick `even` or `odd` depending on the value of `n`. fn pick<T>(n: i32, even: T, odd: T) -> T { if n % 2 == 0 { even } else { odd } } fn main() { println!("picked a number: {:?}", pick(97, 222, 333)); println!("picked a tuple: {:?}", pick(28, ("dog", 1), ("cat", 2))); }
-
Rust infers a type for T based on the types of the arguments and return value.
-
This is similar to C++ templates, but Rust partially compiles the generic function immediately, so that function must be valid for all types matching the constraints. For example, try modifying
pick
to returneven + odd
ifn == 0
. Even if only thepick
instantiation with integers is used, Rust still considers it invalid. C++ would let you do this. -
Generic code is turned into non-generic code based on the call sites. This is a zero-cost abstraction: you get exactly the same result as if you had hand-coded the data structures without the abstraction.