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Exceptions: Difference between revisions
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With Ruby 1.8, you can only "throw" and "catch" symbols. With Ruby 1.9, you can throw and catch any object. Like exceptions, the throw can be made from a function defined elsewhere from the catch block.
=={{header|Rust}}==
In Rust, there is no concept of "exception" per se.
Functions return a Result that can be either an error or a success, and the programmer can chose to panic on an error or not.
It is illustrated by the code below:
<lang Rust>// IO error is used here just as an example of an already existing
// Error
use std::io::{Error, ErrorKind};
// Rust technically doesn't have exception, but different
// types of error handling. Here are two examples of results.
fn valid_function() -> Result<usize, Error> {
Ok(100)
}
fn errored_function() -> Result<usize, Error> {
Err(Error::new(ErrorKind::Other, "Something wrong happened."))
}
// This should happen only when an unrecoverable error happened
fn panicking_function() {
panic!("Unrecoverable state reached");
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_valid_function() {
let result = match valid_function() {
Ok(number) => number,
Err(_) => panic!("This is not going to happen"),
};
assert_eq!(result, 100);
}
#[test]
fn test_errored_function() {
let result = match errored_function() {
Ok(_) => panic!("This is not going to happen"),
Err(e) => {
assert_eq!(e.to_string(), "Something wrong happened.");
0
}
};
assert_eq!(result, 0);
}
#[test]
#[should_panic]
fn test_panicking_function() {
panicking_function();
}
}</lang>
=={{header|Scala}}==
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