std.result

Applies f to a success value; an error passes through unchanged.

• result: The result to map.
• f: Applied to the success value.

let r: Result<int, Error> = ok(2)
println(r.map(|x| x * 10).unwrap()) // 20

Applies f to the error; a success passes through unchanged.

• result: The result to map.
• f: Applied to the error, producing the error to carry instead.

let r: Result<int, Error> = err.Io("disk")
println(r.map_err(|e| err.Wrapped("while saving: " + e.message).unwrap_err()).unwrap_err().name) // Wrapped

Applies f to a success value; an error passes through unchanged.

• result: The result to map.
• f: Applied to the success value.

let r: Result<int, Error> = ok(2)
println(r.map(|x| x * 10).unwrap()) // 20

Recovers from an error with f; a success passes through unchanged.

• result: The result to recover.
• f: Applied to the error; may succeed or fail again.

The success value, otherwise the value f computes from the error.

• result: The result to unwrap.
• f: Called only on an error.

let r: Result<int, Error> = err.Missing("gone")
println(r.unwrap_or_else(|e| e.message.len())) // 4

The error of a failed result; stops the program on a success.

• result: The result expected to have failed.

The success value as an optional; an error becomes absence.

• result: The result to convert.

let r: Result<int, Error> = ok(1)
println(r.ok()) // some(1)

The error as an optional; a success becomes absence.

• result: The result to convert.