1 files changed, 66 insertions, 0 deletions
diff --git a/examples/scala-js/compiler/src/main/scala/scala/scalajs/compiler/JSTreeExtractors.scala b/examples/scala-js/compiler/src/main/scala/scala/scalajs/compiler/JSTreeExtractors.scala
new file mode 100644
index 0000000..a18ad88
--- /dev/null
+++ b/examples/scala-js/compiler/src/main/scala/scala/scalajs/compiler/JSTreeExtractors.scala
@@ -0,0 +1,66 @@
+/* Scala.js compiler
+ * Copyright 2013 LAMP/EPFL
+ * @author  Tobias Schlatter
+ */
+
+package scala.scalajs.compiler
+
+import scala.annotation.tailrec
+
+import scala.scalajs.ir.Trees._
+import scala.scalajs.ir.Types._
+
+/** Useful extractors for JavaScript trees */
+object JSTreeExtractors {
+
+  object jse {
+    /**
+     *  A literally named sequence (like in a call to applyDynamicNamed)
+     *
+     *  Example (Scala): method(("name1", x), ("name2", y))
+     */
+    object LitNamed {
+      def unapply(exprs: List[Tree]) = unapply0(exprs, Nil)
+
+      @tailrec
+      private def unapply0(
+          exprs: List[Tree],
+          acc: List[(StringLiteral, Tree)]
+        ): Option[List[(StringLiteral, Tree)]] = exprs match {
+        case Tuple2(name: StringLiteral, value) :: xs =>
+          unapply0(xs, (name, value) :: acc)
+        case Nil => Some(acc.reverse)
+        case _   => None
+      }
+    }
+
+    /**
+     *  A literal Tuple2
+     *
+     *  Example  (Scala): (x, y)
+     *  But also (Scala): x -> y
+     */
+    object Tuple2 {
+      def unapply(tree: Tree): Option[(Tree, Tree)] = tree match {
+        // case (x, y)
+        case New(ClassType("T2"), Ident("init___O__O", _),
+            List(_1, _2)) =>
+          Some((_1, _2))
+        // case x -> y
+        case Apply(
+            LoadModule(ClassType("s_Predef$ArrowAssoc$")),
+            Ident("$$minus$greater$extension__O__O__T2", _),
+            List(
+              Apply(
+                LoadModule(ClassType("s_Predef$")),
+                Ident("any2ArrowAssoc__O__O", _),
+                List(_1)),
+              _2)) =>
+          Some((_1, _2))
+        case _ =>
+          None
+      }
+    }
+  }
+
+}