CODEWITHSUNDEEP
scalavalidationnestedscalazfold
Hooberd
Hooberd

Reputation: 173

Scalaz ValidationNel - folding

I've recently used ScalaZ for validation purposes and decided to choose ValidationNel as a fail fast behavior wasn't desired. I had more than 12 validation checks to make, thus I couldn't use operator |@| so I've expressed it with <*> like that:

validatePropertyA(object.propertyA) <*>
  (validatePropertyB(object.propertyB) <*>
    (validatePropertyC(object.propertyC) map (_ => _ => _ => object)))

Having about 15 properties to check, this code becomes rather complicated and looks at the first glance like something which could be expressed with foldRight instead, but I don't have a clue how to achieve this.

Is foldRight feasible for the job of making this chunk of code concise or do I have to use something else?

Upvotes: 0

Views: 165

Answers (1)

Luka Jacobowitz
Luka Jacobowitz

Reputation: 23532

You could easily do this using traverse or sequence:

List(validatePropertyA(object.propertyA), validatePropertyB(object.propertyB), ...)
  .sequence.map(_ => object)

That will give you back a Validated with all the errors on the left side and the object on the right side.

Upvotes: 1

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