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LEARN VOID / 08

Results & errors

Make recoverable outcomes explicit.

Represent success and failure with results, then handle both cases.

errors.voidDownload source ↓
func divide(value: i32) -> result<i32, string>:
    if value == 0:
        return Err("division by zero")
    return Ok(100 / value)

func entry(value: i32) -> i32:
    var outcome = divide(value)
    return match outcome:
        Ok(var number): number
        Err(var reason): -1
Input 2Expected result 50

Return success or failure

result<i32, string> carries either an integer success value or a string error. Ok constructs success and Err constructs a recoverable failure.

Handle both cases

match selects the corresponding branch. var number captures the success value; var reason captures the error. Input 2 returns 50, while zero returns -1 through the error branch.

Propagate when appropriate

Inside a compatible result-returning function, ? unwraps success or returns the matching error to its caller. Recoverable results remain distinct from runtime failures such as invalid indexing or a failed checked conversion.