From e353a6f5f618466b6e24e648fa44d64b6a944118 Mon Sep 17 00:00:00 2001
From: Brent Verner <brent.verner@oup.com>
Date: Fri, 18 Jul 2014 13:52:22 -0400
Subject: [PATCH 1/3] correct implementation of difffference; add
 symmetricDifference

---
 set.js           | 13 ++++++++++++-
 test/set-test.js | 13 +++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/set.js b/set.js
index 8070fd4..0329a93 100644
--- a/set.js
+++ b/set.js
@@ -101,11 +101,22 @@ Set.prototype.intersect = function(iset){
   return oset
 }
 
+Set.prototype.symmetricDifference = function(iset){
+  // (A \ B) ∪ (B \ A)
+  return this.difference(iset).union(iset.difference(this));
+}
+
 Set.prototype.difference = function(iset){
+  /* From http://en.wikipedia.org/wiki/Set_theory
+   *   Set difference of U and A, denoted U \ A, is the set of all 
+   *   members of U that are not members of A. The set difference 
+   *   {1,2,3} \ {2,3,4} is {1} , while, conversely, the set difference
+   *   {2,3,4} \ {1,2,3} is {4}
+   */
   var items = iset.get()
     , i = 0
     , l = items.length
-    , oset = this.union(iset)
+    , oset = new Set(this.get())
     , prop
 
   for(; i < l; i++){
diff --git a/test/set-test.js b/test/set-test.js
index aaf30e0..a29a795 100644
--- a/test/set-test.js
+++ b/test/set-test.js
@@ -190,6 +190,19 @@ vows.describe('Set').addBatch({
                 assert.instanceOf(topic, Set)
             }
 
+            , "will get an array of [0,1]": function(topic){
+                assert.deepEqual(topic.get(), [0,1])
+            }
+        }
+        , "when taking the symmetric difference with a Set of [2,3,4,5,6,7]": {
+              topic: function(topic){
+                return topic.symmetricDifference(new Set([2,3,4,5,6,7]))
+              }
+
+            , "will give me a set": function(topic){
+                assert.instanceOf(topic, Set)
+            }
+
             , "will get an array of [0,1,5,6,7]": function(topic){
                 assert.deepEqual(topic.get(), [0,1,5,6,7])
             }

From 096f35c9faa08834786d90678d4600c1f6c2bb16 Mon Sep 17 00:00:00 2001
From: dabreve <dabreve@users.noreply.github.com>
Date: Fri, 18 Jul 2014 13:55:37 -0400
Subject: [PATCH 2/3] Bump version

Bump version to 2.0.0 because of change in behaviour of difference
---
 package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package.json b/package.json
index ca5b831..c01d57f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "set",
-  "version": "1.1.1",
+  "version": "2.0.0",
   "description": "An implementation of Sets in JavaScript",
   "main": "set",
   "scripts": {

From 55b2b3df945bfdb7f4e92b1a4fc877c5a9cf2127 Mon Sep 17 00:00:00 2001
From: dabreve <dabreve@users.noreply.github.com>
Date: Sat, 19 Jul 2014 09:59:11 -0400
Subject: [PATCH 3/3] Revert version bump

---
 package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package.json b/package.json
index c01d57f..ca5b831 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "set",
-  "version": "2.0.0",
+  "version": "1.1.1",
   "description": "An implementation of Sets in JavaScript",
   "main": "set",
   "scripts": {