--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api.test/src/com/oracle/truffle/api/test/FrameTest.java	Tue Dec 18 15:33:55 2012 +0100
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2012, 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.test;
+
+import org.junit.*;
+
+import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.frame.*;
+import com.oracle.truffle.api.nodes.*;
+
+/**
+ * <h3>Storing Values in Frame Slots</h3>
+ *
+ * <p>
+ * The frame is the preferred data structure for passing values between nodes. It can in particular be used for storing
+ * the values of local variables of the guest language. The {@link FrameDescriptor} represents the current structure of
+ * the frame. The method {@link FrameDescriptor#addFrameSlot(String, Class)} can be used to create predefined frame
+ * slots. The setter and getter methods in the {@link Frame} class can be used to access the current value of a
+ * particular frame slot.
+ * </p>
+ *
+ * <p>
+ * There are five primitive types for slots available: {@link java.lang.Boolean}, @{link java.lang.Integer},
+ * {@link java.lang.Long}, {@link java.lang.Float}, and {@link java.lang.Double}. It is encouraged to use those types
+ * whenever possible. Dynamically typed languages can speculate on the type of a value fitting into a primitive (see
+ * {@link FrameSlotTypeSpecializationTest}). When a frame slot is of one of those particular primitive types, its value
+ * may only be accessed with the repectively typed getter method ({@link Frame#getBoolean}, {@link Frame#getInt},
+ * {@link Frame#getLong}, {@link Frame#getFloat}, or {@link Frame#getDouble}) or setter method ({@link Frame#setBoolean},
+ * {@link Frame#setInt}, {@link Frame#setLong}, {@link Frame#setFloat}, or {@link Frame#setDouble}) in the
+ * {@link Frame} class.
+ * </p>
+ *
+ * <p>
+ * The next part of the Truffle API introduction is at
+ * {@link com.oracle.truffle.api.test.FrameSlotTypeSpecializationTest}.
+ * </p>
+ */
+public class FrameTest {
+
+    @Test
+    public void test() {
+        TruffleRuntime runtime = Truffle.getRuntime();
+        FrameDescriptor frameDescriptor = new FrameDescriptor();
+        FrameSlot slot = frameDescriptor.addFrameSlot("localVar", Integer.class);
+        TestRootNode rootNode = new TestRootNode(new AssignLocal(slot), new ReadLocal(slot));
+        CallTarget target = runtime.createCallTarget(rootNode, frameDescriptor);
+        Object result = target.call();
+        Assert.assertEquals(42, result);
+    }
+
+    class TestRootNode extends RootNode {
+
+        @Child TestChildNode left;
+        @Child TestChildNode right;
+
+        public TestRootNode(TestChildNode left, TestChildNode right) {
+            this.left = adoptChild(left);
+            this.right = adoptChild(right);
+        }
+
+        @Override
+        public Object execute(VirtualFrame frame) {
+            return left.execute(frame) + right.execute(frame);
+        }
+    }
+
+    abstract class TestChildNode extends Node {
+        abstract int execute(VirtualFrame frame);
+    }
+
+    abstract class FrameSlotNode extends TestChildNode {
+        protected final FrameSlot slot;
+
+        public FrameSlotNode(FrameSlot slot) {
+            this.slot = slot;
+        }
+    }
+
+    class AssignLocal extends FrameSlotNode {
+        AssignLocal(FrameSlot slot) {
+            super(slot);
+        }
+
+        @Override
+        int execute(VirtualFrame frame) {
+            frame.setInt(slot, 42);
+            return 0;
+        }
+    }
+
+    class ReadLocal extends FrameSlotNode {
+        ReadLocal(FrameSlot slot) {
+            super(slot);
+        }
+
+        @Override
+        int execute(VirtualFrame frame) {
+            return frame.getInt(slot);
+        }
+    }
+}
+