From 47ff69a513f1fc53c444fc60106798bf1fbe4aaa Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Sun, 9 Jun 2019 20:11:05 +0200
Subject: [PATCH] Add quote ConstSeq extractor

---
 .../scala/quoted/matching/ConstSeq.scala      | 22 ++++++++++++++++
 .../quote-matcher-string-interpolator-3.check |  2 ++
 .../quoted_1.scala                            | 26 +++++++++++++++++++
 .../quoted_2.scala                            | 10 +++++++
 4 files changed, 60 insertions(+)
 create mode 100644 library/src-3.x/scala/quoted/matching/ConstSeq.scala
 create mode 100644 tests/run-macros/quote-matcher-string-interpolator-3.check
 create mode 100644 tests/run-macros/quote-matcher-string-interpolator-3/quoted_1.scala
 create mode 100644 tests/run-macros/quote-matcher-string-interpolator-3/quoted_2.scala

diff --git a/library/src-3.x/scala/quoted/matching/ConstSeq.scala b/library/src-3.x/scala/quoted/matching/ConstSeq.scala
new file mode 100644
index 000000000000..8e337cc531bf
--- /dev/null
+++ b/library/src-3.x/scala/quoted/matching/ConstSeq.scala
@@ -0,0 +1,22 @@
+package scala.quoted.matching
+
+import scala.quoted.Expr
+
+import scala.tasty.Reflection // TODO do not depend on reflection directly
+
+/** Literal sequence of literal constant value expressions */
+object ConstSeq {
+
+  /** Matches literal sequence of literal constant value expressions */
+  def unapply[T](expr: Expr[Seq[T]]) given Reflection: Option[Seq[T]] = expr match {
+    case ExprSeq(elems) =>
+      elems.foldRight(Option(List.empty[T])) { (elem, acc) =>
+        (elem, acc) match {
+          case (Const(value), Some(lst)) => Some(value :: lst)
+          case (_, _) => None
+        }
+      }
+    case _ => None
+  }
+
+}
diff --git a/tests/run-macros/quote-matcher-string-interpolator-3.check b/tests/run-macros/quote-matcher-string-interpolator-3.check
new file mode 100644
index 000000000000..254f890b55ba
--- /dev/null
+++ b/tests/run-macros/quote-matcher-string-interpolator-3.check
@@ -0,0 +1,2 @@
+HELLO WORLD
+HELLO World
diff --git a/tests/run-macros/quote-matcher-string-interpolator-3/quoted_1.scala b/tests/run-macros/quote-matcher-string-interpolator-3/quoted_1.scala
new file mode 100644
index 000000000000..2b98a358cd68
--- /dev/null
+++ b/tests/run-macros/quote-matcher-string-interpolator-3/quoted_1.scala
@@ -0,0 +1,26 @@
+import scala.quoted._
+import scala.quoted.matching._
+
+import scala.tasty.Reflection
+
+object Macros {
+
+  inline def (self: => StringContext) S(args: => String*): String = ${impl('self, 'args)}
+
+  private def impl(self: Expr[StringContext], args: Expr[Seq[String]]) given Reflection: Expr[String] = {
+    self match {
+      case '{ StringContext(${ConstSeq(parts)}: _*) } =>
+        val upprerParts: List[String] = parts.toList.map(_.toUpperCase)
+        val upprerPartsExpr: Expr[List[String]] = upprerParts.map(_.toExpr).toExprOfList
+        '{ StringContext($upprerPartsExpr: _*).s($args: _*) }
+      case _ =>
+        '{
+          val parts: Seq[String] = $self.parts
+          val upprerParts = parts.map(_.toUpperCase)
+          StringContext(upprerParts: _*).s($args: _*)
+        }
+    }
+
+  }
+
+}
diff --git a/tests/run-macros/quote-matcher-string-interpolator-3/quoted_2.scala b/tests/run-macros/quote-matcher-string-interpolator-3/quoted_2.scala
new file mode 100644
index 000000000000..7ed4d71a1607
--- /dev/null
+++ b/tests/run-macros/quote-matcher-string-interpolator-3/quoted_2.scala
@@ -0,0 +1,10 @@
+import Macros._
+
+object Test {
+
+  def main(args: Array[String]): Unit = {
+    println(S"Hello World")
+    println(S"Hello ${"World"}")
+  }
+
+}