now it really compiles

1 files changed, 36 insertions, 26 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaMacros.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaMacros.scala
index 343ce1ace1..2e45b14801 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaMacros.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaMacros.scala
@@ -3,19 +3,9 @@ package org.apache.spark.sql.catalyst
 import scala.reflect.macros.blackbox.Context
 import scala.reflect.api.Universe
 
-
-class ScalaMacros(val context: Context) extends ScalaReflection {
-
-  val universe: context.universe.type = context.universe
-
-  def mirror: universe.Mirror = context.mirror
-
-}
-
-
-import scala.language.experimental.macros
-
+import scala.reflect.ClassTag
 import org.apache.spark.sql.Encoder
+import org.apache.spark.sql.catalyst.encoders.ExpressionEncoder
 //import org.apache.spark.sql.catalyst.{InternalRow, JavaTypeInference, ScalaReflection}
 import org.apache.spark.sql.catalyst.analysis.{Analyzer, GetColumnByOrdinal, SimpleAnalyzer, UnresolvedAttribute, UnresolvedExtractValue}
 import org.apache.spark.sql.catalyst.expressions._
@@ -26,20 +16,22 @@ import org.apache.spark.sql.catalyst.plans.logical.{CatalystSerde, DeserializeTo
 import org.apache.spark.sql.types.{BooleanType, ObjectType, StructField, StructType}
 import org.apache.spark.util.Utils
 
-object Macros {
+/** Type parameter is required for a workaround described here http://docs.scala-lang.org/overviews/macros/overview.html
+  * TODO: remove the type parameter once Scala 2.10 is dropped */
+class MacrosHelper[C <: Context](val context: C) extends ScalaReflection {
 
-  implicit def encoder[T]: Encoder[T] = macro encoderImpl[T]
+  val universe: context.universe.type = context.universe
 
-  def encoderImpl[T: c.WeakTypeTag](c: Context): c.Expr[Encoder[T]] = {
-    val helper = new ScalaMacros(c)
-    import helper.universe._
+  val mirror: universe.Mirror = context.mirror
 
-    val tag = implicitly[WeakTypeTag[T]]
+  import universe._
 
+  def generate[T: context.WeakTypeTag]: context.Tree = {
+    val tag = implicitly[WeakTypeTag[T]]
     val tpe = tag.tpe
-    val flat = !helper.definedByConstructorParams(tpe)
 
-    val inputObject = BoundReference(0, helper.dataTypeFor[T](tag), nullable = true)
+    val flat = !definedByConstructorParams(tpe)
+    val inputObject = BoundReference(0, dataTypeFor[T](tag), nullable = true)
     val nullSafeInput = if (flat) {
       inputObject
     } else {
@@ -47,16 +39,34 @@ object Macros {
       // doesn't allow top-level row to be null, only its columns can be null.
       AssertNotNull(inputObject, Seq("top level non-flat input object"))
     }
-    val serializer = helper.serializerFor[T](nullSafeInput)(tag)
-    val deserializer = helper.deserializerFor[T](tag)
+    val serializer = serializerFor[T](nullSafeInput)(tag)
+    val deserializer = deserializerFor[T](tag)
 
-    val schema = helper.schemaFor[T](tag) match {
-      case helper.Schema(s: StructType, _) => s
-      case helper.Schema(dt, nullable) => new StructType().add("value", dt, nullable)
+    val schema = schemaFor[T](tag) match {
+      case Schema(s: StructType, _) => s
+      case Schema(dt, nullable) => new StructType().add("value", dt, nullable)
     }
 
-    ???
+    q"""new _root_.org.apache.spark.sql.catalyst.encoders.ExpressionEncoder[T](
+      ${reify(schema)},
+      ${reify(flat)},
+      ${reify(serializer.flatten)},
+      ${reify(deserializer)},
+      classTag[$tpe])"""
   }
 
+}
+
+
+import scala.language.experimental.macros
+
+object ScalaMacros {
+
+  final def newEncoder[T]: ExpressionEncoder[T] = macro newEncoderImpl[T]
+
+  def newEncoderImpl[T: c.WeakTypeTag](c: Context): c.Expr[ExpressionEncoder[T]] = {
+    val helper = new MacrosHelper[c.type](c)
+    c.Expr[ExpressionEncoder[T]](helper.generate)
+  }
 
 }