How do you unwrap a Result on Ok or return from the function on Err?
You can create a macro:
macro_rules! unwrap_or_return {
( $e:expr ) => {
match $e {
Ok(x) => x,
Err(_) => return,
}
}
}
fn callable(param: &mut i32) -> Result<i32, ()> {
Ok(*param)
}
fn main() {
let mut param = 0;
let res = unwrap_or_return!(callable(&mut param));
println!("{:?}", res);
}
Note that I wouldn't recommend discarding the errors. Rust's error handling is pretty ergonomic, so I would return the error, even if it is only to log it:
fn callable(param: &mut i32) -> Result<i32, ()> {
Ok(*param)
}
fn run() -> Result<(), ()> {
let mut param = 0;
let res = callable(&mut param)?;
println!("{:?}", res);
Ok(())
}
fn main() {
if let Err(()) = run() {
println!("Oops, something went wrong!");
}
}
You can use my unwrap_or crate to accomplish this.
You can do:
unwrap_or_ok!(callable(&mut param), _, return);
And if you want the result and to return the error, you can do:
let v = unwrap_or_ok!(callable(&mut param), error, return error);