CODEWITHSUNDEEP
scalascala-macros
tkroman
tkroman

Reputation: 4808

How do I get a Tree given an Ident?

Say I have lhs, tpe, rhs extracted from this:

q"$mods val $lhs: $tpe = $rhs"

Now, tpe is an Ident. How do I get the Tree (or Type) object corresponding to this ident?

Upvotes: 1

Views: 146

Answers (1)

som-snytt
som-snytt

Reputation: 39587

The Ident is a tree representing a name, and the type is assigned by typechecking.

scala> import reflect.runtime._,universe._,tools.reflect._
import reflect.runtime._
import universe._
import tools.reflect._

scala> val t = q"val i: Int = 42"
t: reflect.runtime.universe.ValDef = val i: Int = 42

scala> val q"val $x: $what = $rhs" = t
x: reflect.runtime.universe.TermName = i
what: reflect.runtime.universe.Tree = Int
rhs: reflect.runtime.universe.Tree = 42

scala> showRaw(what)
res1: String = Ident(TypeName("Int"))

scala> val tb = currentMirror.mkToolBox()
tb: scala.tools.reflect.ToolBox[reflect.runtime.universe.type] = scala.tools.reflect.ToolBoxFactory$ToolBoxImpl@27d5a580

scala> val v = tb.typecheck(t)
v: tb.u.Tree = val i: Int = 42

scala> v.children.head.tpe
res2: tb.u.Type = Int

Upvotes: 2

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