From a088d367f7d22267cc16bbcb7146f26a27168bb1 Mon Sep 17 00:00:00 2001
From: Jack Conradson <osjdconrad@gmail.com>
Date: Mon, 6 Jun 2016 15:58:56 -0700
Subject: [PATCH] More comments.

---
 .../elasticsearch/painless/node/EChain.java   | 12 +++++-----
 .../elasticsearch/painless/node/SDefEach.java | 23 +++++++++++++++++++
 .../elasticsearch/painless/node/SEach.java    |  3 +++
 3 files changed, 32 insertions(+), 6 deletions(-)
 create mode 100644 modules/lang-painless/src/main/java/org/elasticsearch/painless/node/SDefEach.java

diff --git a/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/EChain.java b/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/EChain.java
index df0d670320d..9b2968db565 100644
--- a/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/EChain.java
+++ b/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/EChain.java
@@ -269,14 +269,14 @@ public final class EChain extends AExpression {
      */
     @Override
     void write(MethodWriter writer) {
+        writer.writeDebugInfo(location);
+
         // For the case where the chain represents a String concatenation
-        // we must first write debug information, and then depending on the
-        // Java version write a StringBuilder or track types going onto the
-        // stack.  This must be done before the links in the chain are read
-        // because we need the StringBuilder to be placed on the stack
-        // ahead of any potential concatenation arguments.
+        // we must, depending on the Java version, write a StringBuilder or
+        // track types going onto the stack.  This must be done before the
+        // links in the chain are read because we need the StringBuilder to
+        // be placed on the stack ahead of any potential concatenation arguments.
         if (cat) {
-            writer.writeDebugInfo(location);
             writer.writeNewStrings();
         }
 
diff --git a/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/SDefEach.java b/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/SDefEach.java
new file mode 100644
index 00000000000..000fc42c7a0
--- /dev/null
+++ b/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/SDefEach.java
@@ -0,0 +1,23 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.painless.node;
+
+public class SDefEach {
+}
diff --git a/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/SEach.java b/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/SEach.java
index 0d7e81c2073..3266fdc9ba6 100644
--- a/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/SEach.java
+++ b/modules/lang-painless/src/main/java/org/elasticsearch/painless/node/SEach.java
@@ -88,6 +88,9 @@ public class SEach extends AStatement {
             Type itr = Definition.getType("Iterator");
 
             variable = variables.addVariable(location, type, name, true, false);
+
+            // We must store the iterator as a variable for securing a slot on the stack, and
+            // also add the location offset to make the name unique in case of nested for each loops.
             iterator = variables.addVariable(location, itr, "#itr" + location.getOffset(), true, false);
 
             method = expression.actual.struct.methods.get(new MethodKey("iterator", 0));