eu.timepit.refined.macros.MacroUtils.scala Maven / Gradle / Ivy

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Simple refinement types for Scala

There is a newer version: 0.11.2

package eu.timepit.refined.macros

import eu.timepit.refined.api.{Refined, RefType}
import scala.reflect.macros.blackbox
import scala.util.{Success, Try}
import shapeless.tag.@@

trait MacroUtils {
  val c: blackbox.Context
  import c.universe.weakTypeOf

  def abort(msg: String): Nothing =
    c.abort(c.enclosingPosition, msg)

  def eval[T](t: c.Expr[T]): T = {
    // Duplicate and untypecheck before calling `eval`, see:
    // http://www.scala-lang.org/api/2.12.0/scala-reflect/scala/reflect/macros/Evals.html#eval[T]%28expr:Evals.this.Expr[T]%29:T
    val expr = c.Expr[T](c.untypecheck(t.tree.duplicate))

    // Try evaluating expr twice before failing, see
    // https://github.com/fthomas/refined/issues/3
    tryN(2, c.eval(expr))
  }

  def tryN[T](n: Int, t: => T): T =
    Iterator.fill(n)(Try(t)).collectFirst { case Success(r) => r }.getOrElse(t)

  @deprecated("refTypeInstance is deprecated without replacement", "0.9.16")
  protected def refTypeInstance[F[_, _]](rt: c.Expr[RefType[F]]): RefType[F] =
    if (rt.tree.tpe =:= weakTypeOf[RefType[Refined]])
      RefType.refinedRefType.asInstanceOf[RefType[F]]
    else if (rt.tree.tpe =:= weakTypeOf[RefType[@@]])
      RefType.tagRefType.asInstanceOf[RefType[F]]
    else
      eval(rt)
}