gistfile1.txt

kotlin code: 
  val builder = HtmlBuilder(usersLocale).useLongDates()
  "foo $a bar $b".build(builder)

Creates an anonymous class 

class AnonymousTemplate(a: String, b: Foo) : (String, Foo) {
  fun toString() = "foo " + a + " bar " + b
 
  inline fun build(out: Appender): Unit {
    out.append("foo ")
    out.append(a)
    out.append(" bar ")
    out.append(b)
  }
}

  val builder = HtmlBuilder(usersLocale).useLongDates()
  AnonymousTemplate(a,b).build(builder)

A really smart compiler plugin could just do this to avoid any object construction :) 

    val builder = HtmlBuilder(usersLocale).useLongDates()
    builder.append("foo ")
    builder.append(a)
    builder.append(" bar ")
    builder.append(b)