rustHow to define closure as return type in Rust

In Rust, a closure can be defined as a return type by using the Fn trait. The Fn trait is a trait that allows a closure to be called like a function. To define a closure as a return type, the Fn trait must be specified in the return type declaration. For example:

fn my_function() -> impl Fn(i32) -> i32 {
    |x| x + 1
}

In this example, the closure |x| x + 1 is defined as the return type of the function my_function. The closure takes an i32 as an argument and returns an i32.

The output of this example would be the closure itself, which can then be used like a function. For example:

let my_closure = my_function();
let result = my_closure(5);

println!("The result is {}", result);

Output example:

The result is 6

The Fn trait is a powerful tool for defining closures as return types in Rust. It allows closures to be used like functions, and can be used to create powerful and expressive code.

Helpful links

• The Rust Programming Language - Closures
• The Rust Programming Language - Traits
• The Rust Programming Language - Return Values

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