RFC #21: Result methods

[ProCode-Software]

Should these methods be added to the Result type?

type Result<T, E>
func Result.isSuccess() -> Bool
ok := myResult.isSuccess()
// Without (idiomatic and consistent):
ok := when myResult {
Error -> false
_ -> true
}
func Result.else<U>(errValue: U) -> T | U
value := myResult.else('default value') // Could also be called 'Result.or()'
// Without (also idiomadic and consistent):
value := when myResult {
Error -> 'default value'
_ -> myResult
}
func Result.mapSuccess<U>(to successValue: U) -> Result<U, E>
func Result.mapSuccess<U>(with mapper: func(successValue: T) -> U) -> Result<U, E>
func Result.mapError<U>(to errValue: U) -> Result<T, U> // Could also be called 'Result.and()'
func Result.mapError<U>(with mapper: func(errValue: E) -> U) -> Result<T, U>
func Result.swap() -> Result<E, T> // Could also be called 'Result.invert()'
func Result.takeSuccess() -> T?
func Result.takeError() -> E?