Implement contants extractor in terms of tasty trees

Author: nicolasstucki

compiler/src/dotty/tools/dotc/quoted/Toolbox.scala

@@ -48,19 +48,6 @@ object Toolbox {
     def toTasty(expr: Expr[T]): Term =
       new QuoteDriver().withTree(expr, (tree, ctx) => Term(tree)(ctx), Settings.run())
 
-    def toConstantOpt(expr: Expr[T]): Option[T] = {
-      def toConstantOpt(tree: Tree): Option[T] = tree match {
-        case Literal(Constant(c)) => Some(c.asInstanceOf[T])
-        case Block(Nil, e) => toConstantOpt(e)
-        case Inlined(_, Nil, e) => toConstantOpt(e)
-        case _ => None
-      }
-      expr match {
-        case expr: LiftedExpr[T] => Some(expr.value)
-        case _ => new QuoteDriver().withTree(expr, (tree, _) => toConstantOpt(tree), Settings.run())
-      }
-    }
-
   }
 
   class Settings[T] private (val outDir: Option[String], val rawTree: Boolean, val compilerArgs: List[String])

compiler/src/dotty/tools/dotc/tasty/internal/Constant.scala

@@ -87,6 +87,9 @@ object Constant {
   }
 
   private[tasty] case class Impl(const: Constants.Constant) extends constants.Constant {
+
+    def value: Any = const.value
+
     override def toString: String = {
       import Toolbox.extractor
       this match {

library/src/scala/quoted/Constant.scala

@@ -1,7 +1,18 @@
 package scala.quoted
 
-import scala.runtime.quoted.Toolbox
+import scala.runtime.quoted
+import scala.runtime.tasty
+
+import scala.tasty.trees._
 
 object Constant {
-  def unapply[T](expr: Expr[T])(implicit runner: Toolbox[T]): Option[T] = runner.toConstantOpt(expr)
+  def unapply[T](expr: Expr[T])(implicit qtools: quoted.Toolbox[T], ttools: tasty.Toolbox): Option[T] = {
+    def const(tree: Tree): Option[T] = tree match {
+      case Literal(c) => Some(c.value.asInstanceOf[T])
+      case Block(Nil, e) => const(e)
+      case Inlined(_, Nil, e) => const(e)
+      case _  => None
+    }
+    const(expr.toTasty)
+  }
 }

library/src/scala/runtime/quoted/Toolbox.scala

@@ -9,5 +9,4 @@ trait Toolbox[T] {
   def run(expr: Expr[T]): T
   def show(expr: Expr[T]): String
   def toTasty(expr: Expr[T]): Term
-  def toConstantOpt(expr: Expr[T]): Option[T] // TODO remove and implement with toTasty
 }

library/src/scala/tasty/constants/Constant.scala

@@ -1,3 +1,5 @@
 package scala.tasty.constants
 
-trait Constant
+trait Constant {
+  def value: Any
+}

tests/run-with-compiler/quote-run-constants-extract-1.scala

@@ -1,6 +1,7 @@
 import scala.quoted._
 
 import dotty.tools.dotc.quoted.Toolbox._
+import dotty.tools.dotc.tasty.Toolbox._
 
 object Test {
 

tests/run-with-compiler/quote-run-constants-extract-2.scala

@@ -1,6 +1,7 @@
 import scala.quoted._
 
 import dotty.tools.dotc.quoted.Toolbox._
+import dotty.tools.dotc.tasty.Toolbox._
 
 object Test {
 

tests/run-with-compiler/quote-run-constants-extract-3.scala

@@ -1,6 +1,7 @@
 import scala.quoted._
 
 import dotty.tools.dotc.quoted.Toolbox._
+import dotty.tools.dotc.tasty.Toolbox._
 
 object Test {
 

tests/run-with-compiler/quote-run-constants-extract-4.scala

@@ -1,6 +1,7 @@
 import scala.quoted._
 
 import dotty.tools.dotc.quoted.Toolbox._
+import dotty.tools.dotc.tasty.Toolbox._
 
 object Test {
 

tests/run-with-compiler/quote-run-constants-extract-5.scala

@@ -1,6 +1,7 @@
 import scala.quoted._
 
 import dotty.tools.dotc.quoted.Toolbox._
+import dotty.tools.dotc.tasty.Toolbox._
 
 object Test {