scalaz 7.2.6 flatMap is not a method of Validation?

Question

This works on scalaz 7.0.6, but not on the latest release of scalaz, 7.2.6.

import scalaz._, Scalaz._

def allDigits(s: String): Validation[String, String] =
  if (s.forall(_.isDigit)) s.success else "Not all digits".failure

def maxSizeOfTen(s: String): Validation[String, String] =
  if (s.length <= 10) s.success else "Too big".failure

def toInt(s: String) = try s.toInt.success catch {
  case _: NumberFormatException => "Still not an integer".failure
}

val validated1 = for {
  x <- allDigits("4234")
  y <- maxSizeOfTen(x)
  z <- toInt(y)
} yield z

I get these errors on scalaz 7.2.6:

value flatMap is not a member of scalaz.Validation[String,String]
      x <- allDigits("4234")
value flatMap is not a member of scalaz.Validation[String,String]
      y <- maxSizeOfTen(x)
...

How do I make it work on the latest version of scalaz?

---

Update: Solution based on the accepted answer:

import scalaz._, Scalaz._

def allDigits(s: String): \/[String, String] =
  if (s.forall(_.isDigit)) s.right else "Not all digits".left

def maxSizeOfTen(s: String): \/[String, String] =
  if (s.length <= 10) s.right else "Too big".left

def toInt(s: String) = try s.toInt.right catch {
  case _: NumberFormatException => "Still not an integer".left
}

val validated1 = for {
  x <- allDigits("4234")
  y <- maxSizeOfTen(x)
  z <- toInt(y)
} yield z

Answer 1

As previous answer pointed Validation is useful when you want to run things in parallel and get all the errors at once.

Applicative approach:

def allDigits(s: String): Validation[String, String] =
  if (s.forall(_.isDigit)) s.success else s"|error: '$s' Not all digits ".failure

def maxSizeOfTen(s: String): Validation[String, String] =
  if (s.length <= 10) s.success else s"|error: '$s' Too big".failure

def toInt(s: String) = try s.toInt.success catch {
  case _: NumberFormatException => "|Still not an integer".failure
}

val input = "4234"
val validated1 = (allDigits(input) |@| maxSizeOfTen(input)) { (x, _) => toInt(x) }
println(validated1)

val input2 = "123456789ten"
val validated2 = (allDigits(input2) |@| maxSizeOfTen(input2)) { (x, _) => toInt(x) }
println(validated2)

You will have next output:

Success(Success(4234))
Failure(|error: '123456789ten' Not all digits |error: '123456789ten' Too big)