--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/truffle/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/ASTPrinter.java	Wed Jun 17 10:58:08 2015 +0200
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.api.instrument;
+
+import java.io.*;
+
+import com.oracle.truffle.api.nodes.*;
+
+/**
+ * Access to AST-based debugging support, which is could be language implementation specific in the
+ * details chosen to be presented.
+ * <p>
+ * <strong>WARNING:</strong> this interface is under development and will change substantially.
+ */
+public interface ASTPrinter {
+
+    /**
+     * Prints a textual AST display, one line per node, with nesting.
+     *
+     * @param p
+     * @param node the root node of the display.
+     * @param maxDepth the maximum number of levels to print below the root
+     * @param markNode a node to mark with a textual arrow prefix, if present.
+     */
+    void printTree(PrintWriter p, Node node, int maxDepth, Node markNode);
+
+    /**
+     * Creates a textual AST display, one line per node, with nesting.
+     *
+     * @param node the root node of the display.
+     * @param maxDepth the maximum number of levels to print below the root
+     * @param markNode a node to mark with a textual arrow prefix, if present.
+     */
+    String printTreeToString(Node node, int maxDepth, Node markNode);
+
+    /**
+     * Creates a textual AST display, one line per node, with nesting.
+     *
+     * @param node the root node of the display.
+     * @param maxDepth the maximum number of levels to print below the root
+     */
+    String printTreeToString(Node node, int maxDepth);
+
+    /**
+     * Creates a textual display describing a single (non-wrapper) node, including instrumentation
+     * status: if Probed, and any tags.
+     */
+    String printNodeWithInstrumentation(Node node);
+}