Added a Set data structure.

v3/src/structs/Set.js

@@ -0,0 +1,108 @@
+var Set = function ()
+{
+    this.values = [];
+};
+
+Set.prototype.constructor = Set;
+
+Set.prototype = {
+
+    add: function (value)
+    {
+        if (this.values.indexOf(value) === -1)
+        {
+            this.values.push(value);
+        }
+    },
+
+    delete: function (value)
+    {
+        var index = this.values.indexOf(value);
+
+        if (index > -1)
+        {
+            this.values.splice(index, 1);
+        }
+    },
+
+    clear: function ()
+    {
+        this.values.length = 0;
+    },
+
+    contains: function (value)
+    {
+        return (this.values.indexOf(value) > -1);
+    },
+
+    union: function (set)
+    {
+        var newSet = new Set();
+
+        set.values.forEach(function (value)
+        {
+            newSet.add(value);
+        });
+
+        this.values.forEach(function (value)
+        {
+            newSet.add(value);
+        });
+
+        return newSet;
+    },
+
+    intersect: function (set)
+    {
+        var newSet = new Set();
+
+        this.values.forEach(function (value)
+        {
+            if (set.contains(value))
+            {
+                newSet.add(value);
+            }
+        });
+
+        return newSet;
+    },
+
+    difference: function (set)
+    {
+        var newSet = new Set();
+
+        this.values.forEach(function (value)
+        {
+            if (!set.contains(value))
+            {
+                newSet.add(value);
+            }
+        });
+
+        return newSet;
+    }
+
+};
+
+Object.defineProperties(Set.prototype, {
+
+    length: {
+
+        writable: true,
+        enumerable: false,
+
+        get: function ()
+        {
+            return this.values.length;
+        },
+
+        set: function (value)
+        {
+            return this.values.length = value;
+        }
+
+    }
+
+});
+
+module.exports = Set;