transpose method

Result<Option<T>, E> transpose()

Transposes this Option<Result<T, E>> into a Result<Option<T>, E>.

Returns:

• Ok<Some<T>, E> if this Option is Some<Ok<T, E>>.
• Err<T, E> if this Option is Some<Err<T, E>>.
• Ok<None<T>, E> if this Option is None<Result<T, E>>.

Option<Result<int, String>> a = Some(Ok(1));
Result<Option<int>, String> b = Ok(Some(1));

print(a.transpose() == b); // prints: true

See also: Rust: Option::transpose()

Implementation

Result<Option<T>, E> transpose() => switch (this) {
	Some(v: Ok(:T v)) => Ok(Some(v)),
	Some(v: Err(:E e)) => Err(e),
	None() => Ok(None())
};