--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/nodes/instrument/SLExpressionWrapper.java	Thu Jul 24 16:14:44 2014 -0700
@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2012, 2014, 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.sl.nodes.instrument;
+
+import java.math.*;
+
+import com.oracle.truffle.api.CompilerDirectives.*;
+import com.oracle.truffle.api.frame.*;
+import com.oracle.truffle.api.instrument.*;
+import com.oracle.truffle.api.nodes.*;
+import com.oracle.truffle.sl.nodes.*;
+import com.oracle.truffle.sl.runtime.*;
+
+/**
+ * SLExpressionWrapper is a Truffle AST node that gets inserted as the parent to the node that it is
+ * wrapping. Any debugging instruments are attached to this wrapper through {@link Probe}s (which
+ * themselves contain the instruments. It is through this mechanism that tools can interact directly
+ * with the AST. <br/>
+ * {@link SLExpressionWrapper} specifically wraps {@link SLExpressionNode}s and overrides the
+ * various execute functions in {@link SLExpressionNode} to operate on the child of the wrapper
+ * instead of the wrapper itself.
+ *
+ */
+public final class SLExpressionWrapper extends SLExpressionNode implements Wrapper {
+    @Child private SLExpressionNode child;
+
+    private final Probe probe;
+
+    public SLExpressionWrapper(SLContext context, SLExpressionNode child) {
+        super(child.getSourceSection());
+        assert !(child instanceof SLExpressionWrapper);
+        this.child = insert(child);
+        this.probe = context.getProbe(child.getSourceSection());
+    }
+
+    @Override
+    public SLExpressionNode getNonWrapperNode() {
+        return child;
+    }
+
+    @Override
+    public Node getChild() {
+        return child;
+    }
+
+    @Override
+    public Probe getProbe() {
+        return probe;
+    }
+
+    @Override
+    @SlowPath
+    public boolean isTaggedAs(SyntaxTag tag) {
+        return probe.isTaggedAs(tag);
+    }
+
+    @Override
+    @SlowPath
+    public Iterable<SyntaxTag> getSyntaxTags() {
+        return probe.getSyntaxTags();
+    }
+
+    @SlowPath
+    public void tagAs(SyntaxTag tag) {
+        probe.tagAs(tag);
+    }
+
+    @Override
+    public Object executeGeneric(VirtualFrame frame) {
+        this.tagAs(StandardSyntaxTag.STATEMENT);
+        probe.enter(child, frame);
+        Object result;
+
+        try {
+            result = child.executeGeneric(frame);
+            probe.leave(child, frame, result);
+        } catch (Exception e) {
+            probe.leaveExceptional(child, frame, e);
+            throw (e);
+        }
+        return result;
+    }
+
+    @Override
+    public long executeLong(VirtualFrame frame) throws UnexpectedResultException {
+        this.tagAs(StandardSyntaxTag.STATEMENT);
+        return SLTypesGen.SLTYPES.expectLong(executeGeneric(frame));
+    }
+
+    @Override
+    public BigInteger executeBigInteger(VirtualFrame frame) throws UnexpectedResultException {
+        this.tagAs(StandardSyntaxTag.STATEMENT);
+        return SLTypesGen.SLTYPES.expectBigInteger(executeGeneric(frame));
+    }
+
+    @Override
+    public boolean executeBoolean(VirtualFrame frame) throws UnexpectedResultException {
+        this.tagAs(StandardSyntaxTag.STATEMENT);
+        return SLTypesGen.SLTYPES.expectBoolean(executeGeneric(frame));
+    }
+
+    @Override
+    public String executeString(VirtualFrame frame) throws UnexpectedResultException {
+        this.tagAs(StandardSyntaxTag.STATEMENT);
+        return SLTypesGen.SLTYPES.expectString(executeGeneric(frame));
+    }
+
+    @Override
+    public SLFunction executeFunction(VirtualFrame frame) throws UnexpectedResultException {
+        this.tagAs(StandardSyntaxTag.STATEMENT);
+        probe.enter(child, frame);
+        SLFunction result;
+
+        try {
+            result = child.executeFunction(frame);
+            probe.leave(child, frame, result);
+        } catch (Exception e) {
+            probe.leaveExceptional(child, frame, e);
+            throw (e);
+        }
+        return result;
+    }
+
+    @Override
+    public SLNull executeNull(VirtualFrame frame) throws UnexpectedResultException {
+        return SLTypesGen.SLTYPES.expectSLNull(executeGeneric(frame));
+    }
+}