I have a function that returns a Result: fn find(id: &Id) -> Result<Item, ItemError> { // ... } Then another using it like this: let parent_items: Vec<Item> = parent_ids.ite...

The canonical example of a Warp rejection handler is async fn handle_rejection(err: Rejection) -> Result<impl Reply, Infallible> { But what's the advantage of a Result<ok, err> such...

I would like to write some code in a "functional programming" style. However, I start with an Iterator of Results and I only want to apply the function to the Ok items. Furthermore, I wan...

I cannot return a result of a function from a Result. Every tutorial only shows how to use a Result, but not how to return a value from it. fn main(){ let mut a: Vec<String> = Vec::new(); a...

I am using the Diesel ORM wrapper with PostgreSQL. I was following the guide on their website which has the following code: pub fn establish_connection() -> PgConnection { dotenv().ok(); let ...

I was looking at the std::env::current_dir documentation and this caught my attention: std::io::Result<()> I thought a Result should have a T and an E. How can you substitute them with ()?

My first thought is to map the Option, but I can't use try! from inside of the closure. The match statement looks unnecessary, but I can't figure out how to simplify it. fn example<T, E>(val...

I have code like this: let things = vec![/* ...*/]; // e.g. Vec<String> things .map(|thing| { let a = try!(do_stuff(thing)); Ok(other_stuff(a)) }) .filter(|thing_result| match *th...

I'm using the regex crate to find some text with this regex: lazy_static! { static ref FIND_STEPS_RE: Regex = Regex::new(r"my regex").unwrap(); } I want to find all possible captures and itera...

In Rust, I believe the idiomatic way to deal with recoverable errors is to use Result. For example this function clearly is idiomatic: fn do_work() -> Result<u64, WorkError> {...} Of co...