Macro std::option::try

macro try($opt) { ... }

source

Extract the value or short-circuit the calling function.

When expression is suffixed with ?, this is de-sugared to an invocation of try macro on the expression.

Expands to the following expression 

if $.is_some() {
    $.unwrap()
} else {
    return Option::none()
}

See also try for Result.

Example

fn maybe_sum(maybe_a: Option<i32>, maybe_b: Option<i32>) -> Option<i32> {
    use std::option::try;

    let a = maybe_a?; // `return Option::none()` when `a` is empty.
    let b = maybe_b?; // `return Option::none()` when `a` is empty.

    Option::some(a + b)
}
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