Result
Similar to Option[Char], the enum Result[Char, String] represents a Char value that may or may not be present. If not present, it can contain an error message of type String.
Err("error message")means the value is missing, and the error message is provided.Ok('h')is a wrapper that contains the value'h'.
The processing of Option and Result in examples so far is verbose and prone to bugs. To handle Option and Result values safely and cleanly, you can use pattern matching. It's recommended to use error handling to process errors effectively. These two topics will be covered in a later chapter.
fn first_char(s : String) -> Result[Char, String] {
if s.length() == 0 {
Err("empty string")
} else {
Ok(s[0])
}
}
fn main {
let c1 = first_char("hello")
let c2 = first_char("")
println("\{c1.is_ok()}, \{c1}, \{c1.unwrap()}")
println("\{c2.is_err()}, \{c2}")
}