Return Early vs Nested Imperative Parsing in Swift

gistfile1.swift

static func decodeImperative<X: XMLParsableType>(xml: X) -> Result<Animal> {
  if let type = XMLParser.parseChildText("type")(xml: xml).toOptional() {
    if let name = XMLParser.parseChildText("name")(xml: xml).toOptional() {
      if let urlString = XMLParser.parseChildText("url")(xml: xml).toOptional() {
        return Result.value(self(type: type, name: name, url: NSURL.URLWithString(urlString)) )
      }
      return Result.Error(decodeError("Could not parse 'urlString' as a String"))
    }
    return Result.Error(decodeError("Could not parse 'name' as a String"))
  }
  return Result.Error(decodeError("Could not parse 'type' as a String"))
}

static func decodeImperativeReturnEarly<X: XMLParsableType>(xml: X) -> Result<Animal> {
  let maybeType = XMLParser.parseChildText("type")(xml: xml).toOptional()
  let maybeName = XMLParser.parseChildText("name")(xml: xml).toOptional()
  let maybeUrlString = XMLParser.parseChildText("url")(xml: xml).toOptional()
  
  if maybeType == .None {
    return Result.Error(decodeError("Could not parse 'type' as a String"))
  }
  if maybeName == .None {
    return Result.Error(decodeError("Could not parse 'name' as a String"))
  }
  if maybeUrlString == .None {
    return Result.Error(decodeError("Could not parse 'urlString' as a String"))
  }
  
  return Result.value(self(type: maybeType!, name: maybeName!, url: NSURL.URLWithString(maybeUrlString!)))
}