Value Members

1.  object syntax extends RuleHListSyntax

   Provides rule-builder style methods for refining types during the validation process.

   Provides rule-builder style methods for refining types during the validation process.

   This can be useful for situations where your input types may be raw user input data which you validate, and then from that validation you gain additional context.

   Consider The example below:

   case class InputFoo(untrimmed: String, maybeEmptyList: List[Int], name: String)
   case class ValidatedFoo(trimmed: String, nonEmptyList: NonEmptyList[Int], name: String, thing: Double)
   
   val rule =
     Rule.builder[InputFoo]
       .check("untrimmed", _.untrimmed)(Rule.trimString)
       .check("maybeEmptyList", _.maybeEmptyList)(Rule.nonEmptyList)
       .pass(_.name) // No validation will be performed, but the value for name will be passed through.
       .append(util.Random.nextDouble()) // Appends a random double to the output type
       .build[ValidatedFoo]
   
   rule(InputFoo("bar ", List("baz"))) // Ior.Right(ValidatedFoo("bar", NonEmptyList("baz")))
   rule(InputFoo("bar", List()) // Ior.Left(NonEmptyList(ErrorMessage("Must not be empty", PField("maybeEmptyList", PNil))))

   A user has input an untrimmed string, and a list that may be empty. During the sanitization and validation process, the string is trimmed, and then the List[Int] becomes a NonEmptyList[Int]. This is because the sanitization process can refine the type and hold on to context from the validation phase. This could also be used in conjunction with things like string parsing engines to accept user input strings, parse them in to your AST during sanitization/validation.