3 files changed, 55 insertions, 57 deletions

diff --git a/src/test/Example.Extension/ExampleExtensionFactory.cs b/src/test/Example.Extension/ExampleExtensionFactory.cs
index 9539ee85..b91d06e9 100644
--- a/src/test/Example.Extension/ExampleExtensionFactory.cs
+++ b/src/test/Example.Extension/ExampleExtensionFactory.cs
@@ -7,11 +7,18 @@ namespace Example.Extension
 
     public class ExampleExtensionFactory : IExtensionFactory
     {
+        private ExamplePreprocessorExtensionAndCommandLine preprocessorExtension;
+
         public bool TryCreateExtension(Type extensionType, out object extension)
         {
-            if (extensionType == typeof(IPreprocessorExtension))
+            if (extensionType == typeof(IExtensionCommandLine) || extensionType == typeof(IPreprocessorExtension))
             {
-                extension = new ExamplePreprocessorExtension();
+                if (preprocessorExtension == null)
+                {
+                    preprocessorExtension = new ExamplePreprocessorExtensionAndCommandLine();
+                }
+
+                extension = preprocessorExtension;
             }
             else if (extensionType == typeof(ICompilerExtension))
             {
diff --git a/src/test/Example.Extension/ExamplePreprocessorExtension.cs b/src/test/Example.Extension/ExamplePreprocessorExtension.cs
deleted file mode 100644
index c16c8b5a..00000000
--- a/src/test/Example.Extension/ExamplePreprocessorExtension.cs
+++ /dev/null
@@ -1,55 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-namespace Example.Extension
-{
-    using System;
-    using System.Xml.Linq;
-    using WixToolset.Data;
-    using WixToolset.Extensibility;
-
-    internal class ExamplePreprocessorExtension : IPreprocessorExtension
-    {
-        public ExamplePreprocessorExtension()
-        {
-        }
-
-        public IPreprocessorCore Core { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
-
-        public string[] Prefixes => throw new NotImplementedException();
-
-        public string EvaluateFunction(string prefix, string function, string[] args)
-        {
-            throw new NotImplementedException();
-        }
-
-        public void Finish()
-        {
-            throw new NotImplementedException();
-        }
-
-        public string GetVariableValue(string prefix, string name)
-        {
-            throw new NotImplementedException();
-        }
-
-        public void Initialize()
-        {
-            throw new NotImplementedException();
-        }
-
-        public void PreprocessDocument(XDocument document)
-        {
-            throw new NotImplementedException();
-        }
-
-        public string PreprocessParameter(string name)
-        {
-            throw new NotImplementedException();
-        }
-
-        public bool ProcessPragma(SourceLineNumber sourceLineNumbers, string prefix, string pragma, string args, XContainer parent)
-        {
-            throw new NotImplementedException();
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/test/Example.Extension/ExamplePreprocessorExtensionAndCommandLine.cs b/src/test/Example.Extension/ExamplePreprocessorExtensionAndCommandLine.cs
new file mode 100644
index 00000000..53394ea3
--- /dev/null
+++ b/src/test/Example.Extension/ExamplePreprocessorExtensionAndCommandLine.cs
@@ -0,0 +1,46 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+namespace Example.Extension
+{
+    using System;
+    using System.Collections.Generic;
+    using WixToolset.Extensibility;
+    using WixToolset.Extensibility.Services;
+
+    internal class ExamplePreprocessorExtensionAndCommandLine : BasePreprocessorExtension, IExtensionCommandLine
+    {
+        private string exampleValueFromCommandLine;
+
+        public IEnumerable<ExtensionCommandLineSwitch> CommandLineSwitches => throw new NotImplementedException();
+
+        public ExamplePreprocessorExtensionAndCommandLine()
+        {
+            this.Prefixes = new[] { "ex" };
+        }
+
+        public void PreParse(ICommandLineContext context)
+        {
+        }
+
+        public bool TryParseArgument(IParseCommandLine parseCommandLine, string arg)
+        {
+            if (parseCommandLine.IsSwitch(arg) && arg.Substring(1).Equals("example", StringComparison.OrdinalIgnoreCase))
+            {
+                parseCommandLine.GetNextArgumentOrError(ref this.exampleValueFromCommandLine);
+                return true;
+            }
+
+            return false;
+        }
+
+        public override string GetVariableValue(string prefix, string name)
+        {
+            if (prefix == "ex" && "test".Equals(name, StringComparison.OrdinalIgnoreCase))
+            {
+                return String.IsNullOrWhiteSpace(this.exampleValueFromCommandLine) ? "(null)" : this.exampleValueFromCommandLine;
+            }
+
+            return null;
+        }
+    }
+}
\ No newline at end of file