arrow validation more then 10 fields-CodePudding

all I have a question how can I validate more then 10 values with arrow in kotlin.

fun CreateEventDTO.validate(): Validated<IncorrectInput, CreateEventDTO> =
  name.isEventNameValid()
    .zip(
      about.isAboutValid(),
      phone.isPhoneValid(),
      price.isPriceValid(),
      location.isLocationValid(),
      startDate.isStartDateValid(),
   // TODO add common validation for date
      // endDate.isEndDateValid(),
      status.isEventStatusValid(),
      access.isEventAccessValid(),
      category.isEventCategoryValid(),
      musicStyles.isMusicStyleValid()
    )
    { name, _, _, price, location, status, access, category, musicStyles ->
      CreateEventDTO(
        name = name,
        about = about,
        phone = phone,
        price = price,
        location = location,
        startDate = startDate,
        endDate = endDate,
        status = status,
        access = access,
        category = category,
        musicStyles = musicStyles
      )
    }
    .mapLeft(ApiError::IncorrectInput)

If I will try to add one more validation then I will get an error because zip just allows up to 10values

Required:
Semigroup<TypeVariable(E)>
Found:
ValidatedNel<InvalidAbout, String?> /* = Validated<NonEmptyList<InvalidAbout>, String?> */

is there any other elegant ways to handle this?

CodePudding user response：

Kotlin requires all functions to be explicitly defined, and we cannot define an infinite amount of methods. Therefore Arrow made the decision to limit to 9 arguments.

However, you can easily combine different zip methods with each-other using tuples. For reaching 10 arguments, you can combine 9 2 in the following manner.

fun CreateEventDTO.validate(): Validated<IncorrectInput, CreateEventDTO> =
  name.isEventNameValid()
    .zip(
      about.isAboutValid(),
      phone.isPhoneValid(),
      price.isPriceValid(),
      location.isLocationValid(),
      startDate.isStartDateValid(),
      endDate.isEndDateValid(),
      status.isEventStatusValid(),
      access.isEventAccessValid(),
      category.isEventCategoryValid().zip(musicStyles.isMusicStyleValid(), ::Pair)
    )
    { name, _, _, price, location, startDate, endDate, status, access, (category, musicStyles) ->
      CreateEventDTO(
        name = name,
        about = about,
        phone = phone,
        price = price,
        location = location,
        startDate = startDate,
        endDate = endDate,
        status = status,
        access = access,
        category = category,
        musicStyles = musicStyles
      )
    }
    .mapLeft(ApiError::IncorrectInput)