Skip to main content

Documentation Index

Fetch the complete documentation index at: https://docs.starknet.io/llms.txt

Use this file to discover all available pages before exploring further.

The version of the call operator that takes a by-snapshot receiver. Instances of Fn can be called repeatedly. Fn is implemented automatically by closures whose captured variables are all Copy. Additionally, for any type F that implements Fn, @F implements Fn, too. Since FnOnce is implemented for all implementers of Fn, any instance of Fn can be used as a parameter where a FnOnce is expected. Use Fn as a bound when you want to accept a parameter of function-like type and need to call it repeatedly. If you do not need such strict requirements, use FnOnce as bounds.

​
Signature

pub trait Fn

​
Examples

​
Calling a closure

let square = |x| x * x;
assert_eq!(square(5), 25);

​
Using a Fn parameter

fn call_with_one, +core::ops::Fn[Output: usize]>(func: F) -> usize {
   func(1)
}

let double = |x| x * 2;
assert_eq!(call_with_one(double), 2);

​
Trait functions

​
call

Performs the call operation.

​
Signature

fn call(self: @T, args: Args) -> FnOutput

​
Trait types

​
Output

The returned type after the call operator is used.

​
Signature

type Output;