Validation with scalaz

scalaz_validation.scala

// Start writing your ScalaFiddle code here
import scalaz._
import Scalaz._


case class LoanApplication(
  val firstName: String,
  val lastName: String,
  val nationalRegister: String,
  val emailAddress: Option[String]
)

type Valid[A] = ValidationNel[String, A]
def validateFirstName(firstName: String): Valid[String] = {
  val length = firstName.length
  if (length < 24 && length > 0) firstName.successNel[String] else "error".failureNel[String]
}

def validateLastName(lastName: String): Valid[String] = {
  val length = lastName.length
  if (length < 48 && length > 0) lastName.successNel[String] else "error".failureNel[String]
}

def validateNationalRegister(nationalRegister: String): Valid[String] = {
  val length = nationalRegister.length
  if (length == 11) nationalRegister.successNel[String] else "error".failureNel[String]
}

def validateAll(firstName: String, lastName: String, nationalRegister: String, emailAddressO: Option[String]): Valid[LoanApplication] = {
  
  (
    validateFirstName(firstName) |@|
    validateLastName(lastName)   |@|
    validateNationalRegister(nationalRegister)
  ) { LoanApplication(_, _, _, None) }
  
}

def validateAll2(firstName: String, lastName: String, nationalRegister: String, emailAddressO: Option[String]): Valid[LoanApplication] = {
  
  (
    validateFirstName(firstName) |@|
    validateLastName(lastName)   |@|
    validateNationalRegister(nationalRegister)
  ) { (f, l, n) => LoanApplication(f, l, n, None) }
  
}

println(
  validateAll("Eric", "Honorez", "87102139103", None)  
)

println(
  validateAll("", "Honorez", "87102139103", None)  
)

println(
  validateAll2("", "Honorez", "87102139103", None)  
)