macros - scala - insert value into quasiquote -

unfortunately, intuitive way,

val world = "earth" val tree = q"""println("hello $world")""" 

results in

error:(16, 36) don't know how unquote here val tree = q"""println("hello $world")"""                       ^ 

because $ within quasiquotes expects tree.

val world = "earth" val tree = q"""println(${c.literal(s"hello $world")})""" 

works, ugly , intellij warning c.literal deprecated , should use quasiquotes, instead.

so ... how do this?

update

in response flavian's comment:

import scala.language.experimental.macros import scala.reflect.macros._  object testmacros {    def dotest() = macro impl    def impl(c: blackbox.context)(): c.expr[unit] = {     import c.universe._ //access ast classes     /*     val world = "earth"     val tree = q"""println(${c.literal(s"hello $world")})"""     */      val world = termname("earth")     val tree = q"""println("hello $world")"""      tree match {       case q"""println("hello earth")""" => println("succeeded")       case _ => c.abort(c.enclosingposition, s"huh? was: $tree")     }      c.expr(tree) //wrap tree , tag type   } } 

gives

error:(18, 40) don't know how unquote here     val tree = q"""println("hello $world")"""                                    ^ 

you need termname or that's compiler primitive.

the real problem mixing interpolators, without realising. interpolator in hello world string interpolator, not quasiquote 1 @ unquoting trees suggest.

this 1 way go it:

import c.universe._  val world = termname("earth") val tree = q"""println("hello" + ${world.decodedname.tostring})"""