13.2 Implementation
Similar to functions, implementations require care to remain generic.
struct S; // Concrete type `S`
struct GenericVal<T>(T,); // Generic type `GenericVal`
// impl of GenericVal where we explicitly specify type parameters:
impl GenericVal<f32> {} // Specify `f32`
impl GenericVal<S> {} // Specify `S` as defined above
// `<T>` Must precede the type to remain generic
impl <T> GenericVal<T> {}
struct Val (f64,);
struct GenVal<T>(T,);
// impl of Val
impl Val {
fn value(&self) -> &f64 { &self.0 }
}
// impl of GenVal for a generic type `T`
impl <T> GenVal<T> {
fn value(&self) -> &T { &self.0 }
}
fn main() {
let x = Val(3.0);
let y = GenVal(3i32);
println!("{}, {}", x.value(), y.value());
}