1 files changed, 83 insertions, 0 deletions
diff --git a/runtime/CSharp3/Sources/Antlr3.Runtime/Tree/TreeVisitor.cs b/runtime/CSharp3/Sources/Antlr3.Runtime/Tree/TreeVisitor.cs
new file mode 100644
index 0000000..f6e49ea
--- /dev/null
+++ b/runtime/CSharp3/Sources/Antlr3.Runtime/Tree/TreeVisitor.cs
@@ -0,0 +1,83 @@
+/*
+ * [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
+{
+    using Antlr.Runtime.Misc;
+
+    /** <summary>Do a depth first walk of a tree, applying pre() and post() actions as we go.</summary> */
+    public class TreeVisitor
+    {
+        protected ITreeAdaptor adaptor;
+
+        public TreeVisitor( ITreeAdaptor adaptor )
+        {
+            this.adaptor = adaptor;
+        }
+        public TreeVisitor()
+            : this( new CommonTreeAdaptor() )
+        {
+        }
+
+        /** <summary>
+         *  Visit every node in tree t and trigger an action for each node
+         *  before/after having visited all of its children.  Bottom up walk.
+         *  Execute both actions even if t has no children.  Ignore return
+         *  results from transforming children since they will have altered
+         *  the child list of this node (their parent).  Return result of
+         *  applying post action to this node.
+         *  </summary>
+         */
+        public object Visit( object t, ITreeVisitorAction action )
+        {
+            // System.out.println("visit "+((Tree)t).toStringTree());
+            bool isNil = adaptor.IsNil( t );
+            if ( action != null && !isNil )
+            {
+                t = action.Pre( t ); // if rewritten, walk children of new t
+            }
+            for ( int i = 0; i < adaptor.GetChildCount(t); i++ )
+            {
+                object child = adaptor.GetChild( t, i );
+                Visit( child, action );
+            }
+            if ( action != null && !isNil )
+                t = action.Post( t );
+            return t;
+        }
+
+        public object Visit( object t, Func<object, object> preAction, Func<object, object> postAction )
+        {
+            return Visit( t, new TreeVisitorAction( preAction, postAction ) );
+        }
+    }
+}