1 files changed, 88 insertions, 0 deletions
diff --git a/runtime/CSharp2/Sources/Antlr3.Runtime/Antlr.Runtime.Tree/ITreeVisitorAction.cs b/runtime/CSharp2/Sources/Antlr3.Runtime/Antlr.Runtime.Tree/ITreeVisitorAction.cs
new file mode 100644
index 0000000..6a47bb5
--- /dev/null
+++ b/runtime/CSharp2/Sources/Antlr3.Runtime/Antlr.Runtime.Tree/ITreeVisitorAction.cs
@@ -0,0 +1,88 @@
+/*
+ * [The "BSD licence"]
+ * Copyright (c) 2005-2008 Terence Parr
+ * All rights reserved.
+ *
+ * Conversion to C#:
+ * Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+namespace Antlr.Runtime.Tree
+{
+    /** <summary>
+     *  How to execute code for node t when a visitor visits node t.  Execute
+     *  pre() before visiting children and execute post() after visiting children.
+     *  </summary>
+     */
+    public interface ITreeVisitorAction
+    {
+        /** <summary>
+         *  Execute an action before visiting children of t.  Return t or
+         *  a rewritten t.  It is up to the visitor to decide what to do
+         *  with the return value.  Children of returned value will be
+         *  visited if using TreeVisitor.visit().
+         *  </summary>
+         */
+        object Pre(object t);
+
+        /** <summary>
+         *  Execute an action after visiting children of t.  Return t or
+         *  a rewritten t.  It is up to the visitor to decide what to do
+         *  with the return value.
+         *  </summary>
+         */
+        object Post(object t);
+    }
+
+    public class TreeVisitorAction
+        : ITreeVisitorAction
+    {
+        Func<object, object> _preAction;
+        Func<object, object> _postAction;
+
+        public TreeVisitorAction(Func<object, object> preAction, Func<object, object> postAction)
+        {
+            _preAction = preAction;
+            _postAction = postAction;
+        }
+
+        public object Pre(object t)
+        {
+            if (_preAction != null)
+                return _preAction(t);
+
+            return t;
+        }
+
+        public object Post(object t)
+        {
+            if (_postAction != null)
+                return _postAction(t);
+
+            return t;
+        }
+    }
+}