Usage

Basic usage

import dev.cheleb.scalamigen.*

This import is necessary to bring the implicit conversions into scope.

Now you can use the asForm method on any Var to render a form for the value it holds with double binding.

case class Cat(name: String, age: Int)

val eitherVar = Var(Cat("Scala le chat", 6))

eitherVar.asForm  // (2) form rendering

As long as the case class is built on elments that have a Form[..] instance, the form will be rendered correctly.

Supported types

• String, Int, Long, Double, Boolean
• LocalDate
• Option[A]
• List[A]
• Either[A, B]
• IronType[T, C]
  • Positive

Customizing the form rendering

At anytime you can customize the form rendering by providing a Form instance for the type you want to render.

• opaque type

opaque type Password = String
object Password:
  def apply(password: String): Password = password
  given Form[Password] = secretForm(apply) // (1) form instance

• IronType

doubleGreaterThanEight: Double :| GreaterEqual[8.0]

given IronTypeValidator[Double, GreaterEqual[8.0]] =
    _.toDoubleOption match
      case None         => Left("Not a number")
      case Some(double) => double.refineEither[GreaterEqual[8.0]]