Reducing over ResultType<Value: CollectionType, Error>

gistfile1.txt

public extension ResultType where Value: CollectionType {
  public func reduce<U>(initial: U, @noescape combine: (U, Value.Generator.Element) -> Result<U, Error>) -> Result<U, Error> {
    return analysis(
      ifSuccess: {
        $0.reduce(.Success(initial)) { (acc, item) in
            return acc.flatMap {
              combine($0, item)
            }
        }
      },
      ifFailure: Result<U, Error>.Failure)
  }
}