Newtype

Base class for defining newtypes that have no type parameters.

This class does not define any "builder", or related HasBuilder instance, as you're expected to provide one yourself.

Usage sample:

 type EmailAddress = EmailAddress.Type

 object EmailAddress extends Newtype[String] { self =>
   def apply(value: String): Option[Type] =
     if (value.contains("@"))
       Some(unsafeCoerce(value))
     else
       None

   // Recommended instance, but not required;
   // use Newtype.Validated to get rid of this boilerplate ;-)
   implicit val builder: HasBuilder.Aux[EmailAddress, String] =
     new HasBuilder[EmailAddress] {
       type Source = String

       def build(v: String): Either[BuildFailure[Type], Type] =
         apply(v) match {
           case Some(r) =>
             Right(r)
           case None =>
             Left(BuildFailure[EmailAddress]("missing @"))
         }
     }
 }