diff --git a/msu/classes/set.nut b/msu/classes/set.nut
new file mode 100644
index 000000000..166da63f7
--- /dev/null
+++ b/msu/classes/set.nut
@@ -0,0 +1,97 @@
+::MSU.Class.Set <- class
+{
+	Table = null; // Cannot contain null
+
+	constructor( _tableOrArray = null )
+	{
+		this.Table = {};
+		if (_tableOrArray != null)
+		{
+			switch (typeof _tableOrArray)
+			{
+				case "table":
+					foreach (key, _ in _tableOrArray)
+						this.add(key);
+					break;
+
+				case "array":
+					foreach (item in _tableOrArray)
+						this.add(item);
+					break;
+
+				default:
+					throw ::MSU.Exception.InvalidType(_tableOrArray);
+			}
+		}
+	}
+
+	function _cloned( _original )
+	{
+		this.Table = clone _original.Table;
+	}
+
+	// Used for iterating over the set e.g. foreach (item in mySet.toArray())
+	// We don't implement _nexti because of two reasons:
+	// - It is orders of magnitude slower than iterating on a table
+	// - It is not compatible with nested foreach loops where you have a "break" in the nested loop
+	function toArray()
+	{
+		return ::MSU.Table.keys(this.Table);
+	}
+
+	function add( _item )
+	{
+		this.Table[_item] <- false;
+	}
+
+	function remove( _item )
+	{
+		if (!(_item in this.Table))
+			throw ::MSU.Exception.KeyNotFound(_item);
+		delete this.Table[_item];
+	}
+
+	function contains( _item )
+	{
+		return _item in this.Table;
+	}
+
+	function apply( _function )
+	{
+		// _function ( _item )
+		// must return value that will replace _item in this set
+
+		local newTable = {};
+		foreach (item, _ in this.Table)
+		{
+			newTable[_function(item)] <- false;
+		}
+		this.Table = newTable;
+	}
+
+	function map( _function )
+	{
+		// _function ( _item )
+		// must return value that will be stored in the returned set instead of _item
+
+		local ret = ::MSU.Class.Set();
+		foreach (item, _ in this.Table)
+		{
+			ret.add(_function(item))
+		}
+		return ret;
+	}
+
+	function filter( _function )
+	{
+		// _function ( _item  )
+		// must return a boolean, if false then _item is not added to the returned set
+
+		local ret = ::MSU.Class.Set();
+		foreach (item, _ in this.Table)
+		{
+			if (_function(item)) ret.add(item);
+		}
+		return ret;
+	}
+}