Add MacroStringInterpolator framework

Author: nicolasstucki

tests/run-separate-compilation/tasty-interpolation-1.check

@@ -0,0 +1,77 @@
+
+import scala.quoted._
+import scala.tasty.Reflection
+import scala.language.implicitConversions
+import scala.quoted.Exprs.LiftedExpr
+import scala.quoted.Toolbox.Default._
+
+object Macro {
+
+  class StringContextOps(strCtx: => StringContext) {
+    inline def foo(args: Any*): String = ~SIntepolator('(strCtx), '(args))
+  }
+  implicit inline def SCOps(strCtx: => StringContext): StringContextOps = new StringContextOps(strCtx)
+
+}
+
+object SIntepolator extends MacroStringInterpolator[String] {
+
+  // TODO remove this
+  override def apply(strCtxExpr: Expr[StringContext], argsExpr: Expr[Seq[Any]])(implicit reflect: Reflection): Expr[String] = {
+    super.apply(strCtxExpr, argsExpr)
+  }
+
+  override def interpolate(strCtx: StringContext, args: List[Expr[Any]])(implicit reflect: Reflection): Expr[String] =
+    '(StringContext(~strCtx.parts.toList.toExpr: _*).s(~args.toExprOfList: _*))
+
+  // TODO use stdlib
+  implicit def l: Liftable[List[String]] = new Liftable[List[String]] {
+    override def toExpr(list: List[String]): Expr[List[String]] = list match {
+      case x :: xs => '(~x.toExpr :: ~toExpr(xs))
+      case Nil => '(Nil)
+    }
+  }
+}
+
+abstract class MacroStringInterpolator[T] {
+
+  /*final*/ def apply(strCtxExpr: Expr[StringContext], argsExpr: Expr[Seq[Any]])(implicit reflect: Reflection): Expr[T] = {
+    interpolate(strCtxExpr, argsExpr)
+  }
+
+  def interpolate(strCtxExpr: Expr[StringContext], argsExpr: Expr[Seq[Any]])(implicit reflect: Reflection): Expr[T] = {
+    val strCtx = getStaticStringContext(strCtxExpr).getOrElse(throw new QuoteError("Expected statically known StringContext"))
+    val argExprs = getArgsList(argsExpr).getOrElse(throw new QuoteError("Expected statically known argument list"))
+    interpolate(strCtx, argExprs)
+  }
+
+  def interpolate(strCtx: StringContext, argExprs: List[Expr[Any]])(implicit reflect: Reflection): Expr[T] = {
+//    argExprs.toExprOfList
+//    '(StringContext(~strCtx.parts.toList.toExpr: _*).s(~args: _*))
+    ???
+  }
+
+  protected def getStaticStringContext(strCtxExpr: Expr[StringContext])(implicit reflect: Reflection): Option[StringContext] = {
+    import reflect._
+    strCtxExpr.unseal.underlyingArgument match {
+      case Term.Select(Term.Typed(Term.Apply(_, List(Term.Apply(_, List(Term.Typed(Term.Repeated(strCtxArgTrees), TypeTree.Inferred()))))), _), _) =>
+        val strCtxArgs = strCtxArgTrees.map {
+          case Term.Literal(Constant.String(str)) => str
+          case _ => return None
+        }
+        Some(StringContext(strCtxArgs: _*))
+      case _ =>
+        None
+    }
+  }
+
+  protected def getArgsList(argsExpr: Expr[Seq[Any]])(implicit reflect: Reflection): Option[List[Expr[Any]]] = {
+    import reflect._
+    argsExpr.unseal.underlyingArgument match {
+      case Term.Typed(Term.Repeated(args), _) => Some(args.map(_.seal[Any]))
+      case _ => None
+    }
+  }
+
+
+}

tests/run-separate-compilation/tasty-interpolation-1/Macro.scala

@@ -0,0 +1,9 @@
+import Macro._
+
+object Test {
+  def main(args: Array[String]): Unit = {
+
+    println(foo"Hello ${"world"}!")
+
+  }
+}