String interpolation + pattern matching = PROFIT

PROFIT.scala

import RegexInterpolations._

val str = "My hovercraft is full of eels"
str match {
  case r"""My (\w+)$vehicle is full of (\w+)$stuff""" =>
    println(s"It is $stuff that my $vehicle is full of.")
}

RegexInterpolations.scala

import java.util.regex.Pattern

object RegexInterpolations {
  implicit class Interpolations(sc: StringContext) {
    def r = new PartsRegex(sc.parts)
  }

  class PartsRegex(parts: Seq[String]) {
    private val regex = parts.mkString

    private val matchedGroups = {
      // indices of pattern's string interpolation arguments
      val matchedGroupIndexes =
        parts.iterator.map(_.length).scanLeft(0)(_ + _).map(_ - 1).drop(1).take(parts.size - 1).toSet

      val matchedGroupsBuilder = Seq.newBuilder[Int]
      var group = 0
      var level = 0
      var escaping = false
      regex.zipWithIndex.foreach {
        case ('(', _) if !escaping =>
          group += 1
          level += 1
        case (')', index) if !escaping =>
          level -= 1
          if (matchedGroupIndexes contains index) {
            matchedGroupsBuilder += (group - level)
          }
        case ('\\', _) if !escaping =>
          escaping = true
        case _ =>
          escaping = false
      }

      matchedGroupsBuilder.result()
    }

    def unapplySeq(str: String) = {
      val matcher = Pattern.compile(regex).matcher(str)
      if (matcher.matches) Some(matchedGroups.map(matcher.group)) else None
    }
  }
}