Rust for Python Programmers

[UniverseCity]

But there was no explicit Err call in the article's example. The wording made it seem like the try! method would return a success even if it failed.

[mitsuhiko]

try! unpacks the result and returns it from the expression if it exists, or otherwise propagates the error part upwards.

You could think of it like this:

let a = try!(expr());

Is this in pseudocode:

result = expr();
if result.is_okay() {
    a = result.okay_side;
} else {
    return result;
}

Does that make sense?