--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/Source.java	Tue Apr 23 14:59:24 2013 +0200
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2013, 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.
+ *
+ * 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;
+
+/**
+ * Represents the source code of a guest language program.
+ */
+public interface Source {
+
+    /**
+     * Returns the name of this resource holding a guest language program. An example would be the
+     * name of a guest language source code file.
+     * 
+     * @return the name of the guest language program
+     */
+    String getName();
+
+    /**
+     * Returns the guest language source code represented by this source object.
+     * 
+     * @return the source code as a String object
+     */
+    String getCode();
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/SourceSection.java	Tue Apr 23 14:59:24 2013 +0200
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2013, 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.
+ *
+ * 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;
+
+/**
+ * Represents a section in the source code of a guest language program.
+ */
+public class SourceSection {
+
+    private final Source source;
+    private final String identifier;
+    private final int startLine;
+    private final int startColumn;
+    private final int endLine;
+    private final int endColumn;
+
+    /**
+     * Creates a new object representing a section in the source code of a guest language program.
+     * 
+     * @param source object representing the source program this is should be a section of
+     * @param identifier an identifier used when printing the section
+     * @param startLine the index of the start line of the section (inclusive)
+     * @param startColumn the index of the start column of the section (inclusive)
+     * @param endLine the index of the end line of the section (inclusive)
+     * @param endColumn the index of the end column of the section (inclusive)
+     */
+    public SourceSection(Source source, String identifier, int startLine, int startColumn, int endLine, int endColumn) {
+        this.source = source;
+        this.identifier = identifier;
+        this.startLine = startLine;
+        this.startColumn = startColumn;
+        this.endLine = endLine;
+        this.endColumn = endColumn;
+    }
+
+    /**
+     * Returns the source object representing the source program this is a section of.
+     * 
+     * @return the source object
+     */
+    public final Source getSource() {
+        return source;
+    }
+
+    /**
+     * Returns the index of the start line of this source section (inclusive).
+     * 
+     * @return the start line
+     */
+    public final int getStartLine() {
+        return startLine;
+    }
+
+    /**
+     * Returns the index of the start column of this source section (inclusive).
+     * 
+     * @return the start column
+     */
+    public final int getStartColumn() {
+        return startColumn;
+    }
+
+    /**
+     * Returns the index of the end line of this source section (inclusive).
+     * 
+     * @return the end line
+     */
+    public final int getEndLine() {
+        return endLine;
+    }
+
+    /**
+     * Returns the index of the end column of this source section (inclusive).
+     * 
+     * @return the end column
+     */
+    public final int getEndColumn() {
+        return endColumn;
+    }
+
+    /**
+     * Returns the identifier of this source section that is used for printing the section.
+     * 
+     * @return the identifier of the section
+     */
+    public final String getIdentifier() {
+        return identifier;
+    }
+}

--- a/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/nodes/Node.java	Tue Apr 23 11:29:55 2013 +0200
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/nodes/Node.java	Tue Apr 23 14:59:24 2013 +0200
@@ -25,6 +25,8 @@
 import java.lang.annotation.*;
 import java.util.*;
 
+import com.oracle.truffle.api.*;
+
 /**
  * Abstract base class for all Truffle nodes.
  */
@@ -37,6 +39,8 @@
 
     private Node parent;
 
+    private SourceSection sourceSection;
+
     /**
      * Marks array fields that are children of this node.
      */
@@ -54,6 +58,34 @@
     }
 
     /**
+     * Assigns a link to a guest language source section to this node.
+     * 
+     * @param section the object representing a section in guest language source code
+     */
+    public final void assignSourceSection(SourceSection section) {
+        if (sourceSection != null) {
+            throw new IllegalStateException("Source section is already assigned.");
+        }
+        this.sourceSection = section;
+    }
+
+    /**
+     * Clears any previously assigned guest language source code from this node.
+     */
+    public final void clearSourceSection() {
+        this.sourceSection = null;
+    }
+
+    /**
+     * Retrieves the guest language source code section that is currently assigned to this node.
+     * 
+     * @return the assigned source code section
+     */
+    public final SourceSection getSourceSection() {
+        return sourceSection;
+    }
+
+    /**
      * Method that updates the link to the parent in the array of specified new child nodes to this
      * node.
      * 
@@ -123,7 +155,7 @@
      * @return the new node
      */
     @SuppressWarnings({"unchecked"})
-    public <T extends Node> T replace(T newNode, String reason) {
+    public final <T extends Node> T replace(T newNode, String reason) {
         assert this.getParent() != null;
         return (T) this.getParent().replaceChild(this, newNode);
     }
@@ -134,7 +166,7 @@
      * @param newNode the new node that is the replacement
      * @return the new node
      */
-    public <T extends Node> T replace(T newNode) {
+    public final <T extends Node> T replace(T newNode) {
         return replace(newNode, "");
     }