[422933] Improve stepping and presentation

10 files changed, 548 insertions, 75 deletions

diff --git a/plugins/org.eclipse.qvtd.debug.ui/src/org/eclipse/qvtd/debug/ui/pages/QVTiDebugModelPresentation.java b/plugins/org.eclipse.qvtd.debug.ui/src/org/eclipse/qvtd/debug/ui/pages/QVTiDebugModelPresentation.java
index c27d9336e..38539c3df 100644
--- a/plugins/org.eclipse.qvtd.debug.ui/src/org/eclipse/qvtd/debug/ui/pages/QVTiDebugModelPresentation.java
+++ b/plugins/org.eclipse.qvtd.debug.ui/src/org/eclipse/qvtd/debug/ui/pages/QVTiDebugModelPresentation.java
@@ -45,7 +45,6 @@ import org.eclipse.ui.IEditorInput;
 import org.eclipse.ui.IEditorPart;
 import org.eclipse.ui.part.FileEditorInput;
 
-
 public class QVTiDebugModelPresentation implements IDebugModelPresentation, IDebugEditorPresentation, IDebugModelPresentationExtension, IColorProvider, ILabelProvider {
 	
 	public QVTiDebugModelPresentation() {
@@ -56,9 +55,15 @@ public class QVTiDebugModelPresentation implements IDebugModelPresentation, IDeb
 	}
 
     public Image getImage(Object element) {
-//    	System.out.println("getImage: " + element.getClass().getSimpleName() + " " + element);
-    	if (element instanceof VMStackFrame) {
-        	VMStackFrame frame = (VMStackFrame) element;
+    	if (element instanceof VMDebugTarget) {
+    		return QVTiDebugImages.getImage(QVTiDebugImages.TRANSFORMATION);
+    	}
+    	else if (element instanceof VMThread) {
+        	return null;
+        }
+    	else if (element instanceof VMStackFrame) {
+        	return null;
+/*        	VMStackFrame frame = (VMStackFrame) element;
     		VMLocationData location = frame.getLocation();
     		String elementSignature = location.getElementSignature();
             if (elementSignature != null) {
@@ -66,7 +71,7 @@ public class QVTiDebugModelPresentation implements IDebugModelPresentation, IDeb
             }
             else {
     			return QVTiDebugImages.getImage(QVTiDebugImages.TRANSFORMATION);
-            } 
+            }  */
         }
         else if(element instanceof VMVariable) {
     		VMVariable var = (VMVariable) element;
@@ -111,17 +116,28 @@ public class QVTiDebugModelPresentation implements IDebugModelPresentation, IDeb
 	}
 
 	public String getText(Object element) {
-//    	System.out.println("getText: " + element.getClass().getSimpleName() + " " + element);
-        if (element instanceof VMStackFrame) {
+        if (element instanceof VMDebugTarget) {
+        	VMDebugTarget debugTarget = (VMDebugTarget) element;
+			String moduleName = debugTarget.getMainModuleName();
+			String launchConfigName = debugTarget.getLaunch().getLaunchConfiguration().getName();
+			return NLS.bind(DebugUIMessages.QVTiDebugModelPresentation_TransformationLabel, moduleName, launchConfigName);
+        }
+        else if (element instanceof VMThread) {
+        	VMThread thread = (VMThread) element;
+        	String name = "main"; //$NON-NLS-1$
+        	String state = thread.isSuspended() ? DebugUIMessages.QVTiDebugModelPresentation_Suspended : DebugUIMessages.QVTiDebugModelPresentation_Running;
+        	return MessageFormat.format(DebugUIMessages.QVTiDebugModelPresentation_ThreadLabel, name, state);
+        } 
+        else if (element instanceof VMStackFrame) {
         	VMStackFrame frame = (VMStackFrame) element;
     		VMLocationData location = frame.getLocation();
     		String source = frame.getUnitURI().lastSegment();
     		int line = frame.getLineNumber();
             StringBuilder s = new StringBuilder();
-            s.append(location.getModule());
+//            s.append(location.getModule());
             String elementSignature = location.getElementSignature();
             if (elementSignature != null) {
-            	s.append("::");
+//            	s.append("::");
             	s.append(elementSignature);
             }
         	s.append(" - ");
@@ -130,18 +146,6 @@ public class QVTiDebugModelPresentation implements IDebugModelPresentation, IDeb
         	s.append(line);
             return s.toString();
         } 
-        else if (element instanceof VMThread) {
-        	VMThread thread = (VMThread) element;
-        	String name = "main"; //$NON-NLS-1$
-        	String state = thread.isSuspended() ? DebugUIMessages.QVTiDebugModelPresentation_Suspended : DebugUIMessages.QVTiDebugModelPresentation_Running;
-        	return MessageFormat.format(DebugUIMessages.QVTiDebugModelPresentation_ThreadLabel, name, state);
-        } 
-        else if (element instanceof VMDebugTarget) {
-        	VMDebugTarget debugTarget = (VMDebugTarget) element;
-			String moduleName = debugTarget.getMainModuleName();
-			String launchConfigName = debugTarget.getLaunch().getLaunchConfiguration().getName();
-			return NLS.bind(DebugUIMessages.QVTiDebugModelPresentation_TransformationLabel, moduleName, launchConfigName);
-        }
         return null;
 	}
 
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/evaluator/QVTiStepperVisitor.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/evaluator/QVTiStepperVisitor.java
deleted file mode 100644
index 3fae84f86..000000000
--- a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/evaluator/QVTiStepperVisitor.java
+++ /dev/null
@@ -1,17 +0,0 @@
-/*******************************************************************************
- * Copyright (c) 2014 E.D.Willink and others.
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Eclipse Public License v1.0
- * which accompanies this distribution, and is available at
- * http://www.eclipse.org/legal/epl-v10.html
- *
- * Contributors:
- *   E.D.Willink - Initial API and implementation
- *******************************************************************************/
-package org.eclipse.qvtd.debug.evaluator;
-
-import org.eclipse.ocl.examples.debug.stepper.OCLStepperVisitor;
-
-public class QVTiStepperVisitor extends OCLStepperVisitor {
-
-}
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTbaseStepperVisitor.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTbaseStepperVisitor.java
new file mode 100644
index 000000000..6113bb640
--- /dev/null
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTbaseStepperVisitor.java
@@ -0,0 +1,87 @@
+/**
+ * <copyright>
+ * 
+ * Copyright (c) 2013 E.D.Willink and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *   E.D.Willink - Initial API and implementation
+ * 
+ * </copyright>
+ *
+ * This code is auto-generated
+ * from: org.eclipse.qvtd.pivot.qvtbase/model/QVTbase.genmodel
+ *
+ * Do not edit it.
+ */
+package	org.eclipse.qvtd.debug.stepper;
+
+import org.eclipse.ocl.examples.debug.stepper.OCLStepperVisitor;
+import org.eclipse.ocl.examples.debug.vm.evaluator.IStepper;
+import org.eclipse.qvtd.pivot.qvtbase.util.QVTbaseVisitor;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
+
+/**
+ * An AbstractQVTbaseStepperVisitor provides a default implementation for each
+ * visitXxx method that delegates to the visitYyy method of the first
+ * super class, (or transitively its first super class' first super class
+ * until a non-interface super-class is found). In the absence of any
+ * suitable first super class, the method delegates to visiting().
+ */
+public abstract class AbstractQVTbaseStepperVisitor
+	extends OCLStepperVisitor
+	implements QVTbaseVisitor<IStepper>
+{
+	/**
+	 * Initializes me with an initial value for my result.
+	 * 
+	 * @param context my initial result value
+	 */
+	protected AbstractQVTbaseStepperVisitor(@NonNull Object context) {
+		super();
+	}	
+
+	public @Nullable IStepper visitBaseModel(@NonNull org.eclipse.qvtd.pivot.qvtbase.BaseModel object) {
+		return visitRoot(object);
+	}
+
+	public @Nullable IStepper visitDomain(@NonNull org.eclipse.qvtd.pivot.qvtbase.Domain object) {
+		return visitNamedElement(object);
+	}
+
+	public @Nullable IStepper visitFunction(@NonNull org.eclipse.qvtd.pivot.qvtbase.Function object) {
+		return visitOperation(object);
+	}
+
+	public @Nullable IStepper visitFunctionParameter(@NonNull org.eclipse.qvtd.pivot.qvtbase.FunctionParameter object) {
+		return visitParameter(object);
+	}
+
+	public @Nullable IStepper visitPattern(@NonNull org.eclipse.qvtd.pivot.qvtbase.Pattern object) {
+		return visitElement(object);
+	}
+
+	public @Nullable IStepper visitPredicate(@NonNull org.eclipse.qvtd.pivot.qvtbase.Predicate object) {
+		return visitElement(object);
+	}
+
+	public @Nullable IStepper visitRule(@NonNull org.eclipse.qvtd.pivot.qvtbase.Rule object) {
+		return visitNamedElement(object);
+	}
+
+	public @Nullable IStepper visitTransformation(@NonNull org.eclipse.qvtd.pivot.qvtbase.Transformation object) {
+		return visitClass(object);
+	}
+
+	public @Nullable IStepper visitTypedModel(@NonNull org.eclipse.qvtd.pivot.qvtbase.TypedModel object) {
+		return visitNamedElement(object);
+	}
+
+	public @Nullable IStepper visitUnit(@NonNull org.eclipse.qvtd.pivot.qvtbase.Unit object) {
+		return visitNamedElement(object);
+	}
+}
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTcoreBaseStepperVisitor.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTcoreBaseStepperVisitor.java
new file mode 100644
index 000000000..96e4701f1
--- /dev/null
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTcoreBaseStepperVisitor.java
@@ -0,0 +1,82 @@
+/**
+ * <copyright>
+ * 
+ * Copyright (c) 2013 E.D.Willink and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *   E.D.Willink - Initial API and implementation
+ * 
+ * </copyright>
+ *
+ * This code is auto-generated
+ * from: org.eclipse.qvtd.pivot.qvtcorebase/model/QVTcoreBase.genmodel
+ *
+ * Do not edit it.
+ */
+package	org.eclipse.qvtd.debug.stepper;
+
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
+import org.eclipse.ocl.examples.debug.vm.evaluator.IStepper;
+import org.eclipse.qvtd.pivot.qvtcorebase.util.QVTcoreBaseVisitor;
+
+/**
+ * An AbstractQVTcoreBaseStepperVisitor provides a default implementation for each
+ * visitXxx method that delegates to the visitYyy method of the first
+ * super class, (or transitively its first super class' first super class
+ * until a non-interface super-class is found). In the absence of any
+ * suitable first super class, the method delegates to visiting().
+ */
+public abstract class AbstractQVTcoreBaseStepperVisitor
+	extends AbstractQVTbaseStepperVisitor
+	implements QVTcoreBaseVisitor<IStepper>
+{
+	/**
+	 * Initializes me with an initial value for my result.
+	 * 
+	 * @param context my initial result value
+	 */
+	protected AbstractQVTcoreBaseStepperVisitor(@NonNull Object context) {
+		super(context);
+	}	
+
+	public @Nullable IStepper visitAssignment(@NonNull org.eclipse.qvtd.pivot.qvtcorebase.Assignment object) {
+		return visitElement(object);
+	}
+
+	public @Nullable IStepper visitBottomPattern(@NonNull org.eclipse.qvtd.pivot.qvtcorebase.BottomPattern object) {
+		return visitCorePattern(object);
+	}
+
+	public @Nullable IStepper visitCoreDomain(@NonNull org.eclipse.qvtd.pivot.qvtcorebase.CoreDomain object) {
+		return visitDomain(object);
+	}
+
+	public @Nullable IStepper visitCorePattern(@NonNull org.eclipse.qvtd.pivot.qvtcorebase.CorePattern object) {
+		return visitPattern(object);
+	}
+
+	public @Nullable IStepper visitEnforcementOperation(@NonNull org.eclipse.qvtd.pivot.qvtcorebase.EnforcementOperation object) {
+		return visitElement(object);
+	}
+
+	public @Nullable IStepper visitGuardPattern(@NonNull org.eclipse.qvtd.pivot.qvtcorebase.GuardPattern object) {
+		return visitCorePattern(object);
+	}
+
+	public @Nullable IStepper visitPropertyAssignment(@NonNull org.eclipse.qvtd.pivot.qvtcorebase.PropertyAssignment object) {
+		return visitAssignment(object);
+	}
+
+	public @Nullable IStepper visitRealizedVariable(@NonNull org.eclipse.qvtd.pivot.qvtcorebase.RealizedVariable object) {
+		return visitVariable(object);
+	}
+
+	public @Nullable IStepper visitVariableAssignment(@NonNull org.eclipse.qvtd.pivot.qvtcorebase.VariableAssignment object) {
+		return visitAssignment(object);
+	}
+}
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTimperativeStepperVisitor.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTimperativeStepperVisitor.java
new file mode 100644
index 000000000..b87218670
--- /dev/null
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTimperativeStepperVisitor.java
@@ -0,0 +1,74 @@
+/**
+ * <copyright>
+ * 
+ * Copyright (c) 2013 E.D.Willink and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *   E.D.Willink - Initial API and implementation
+ * 
+ * </copyright>
+ *
+ * This code is auto-generated
+ * from: org.eclipse.qvtd.pivot.qvtimperative/model/QVTimperative.genmodel
+ *
+ * Do not edit it.
+ */
+package	org.eclipse.qvtd.debug.stepper;
+
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
+import org.eclipse.ocl.examples.debug.vm.evaluator.IStepper;
+import org.eclipse.qvtd.pivot.qvtimperative.util.QVTimperativeVisitor;
+
+/**
+ * An AbstractQVTimperativeStepperVisitor provides a default implementation for each
+ * visitXxx method that delegates to the visitYyy method of the first
+ * super class, (or transitively its first super class' first super class
+ * until a non-interface super-class is found). In the absence of any
+ * suitable first super class, the method delegates to visiting().
+ */
+public abstract class AbstractQVTimperativeStepperVisitor
+	extends AbstractQVTcoreBaseStepperVisitor
+	implements QVTimperativeVisitor<IStepper>
+{
+	/**
+	 * Initializes me with an initial value for my result.
+	 * 
+	 * @param context my initial result value
+	 */
+	protected AbstractQVTimperativeStepperVisitor(@NonNull Object context) {
+		super(context);
+	}	
+
+	public @Nullable IStepper visitImperativeModel(@NonNull org.eclipse.qvtd.pivot.qvtimperative.ImperativeModel object) {
+		return visitBaseModel(object);
+	}
+
+	public @Nullable IStepper visitMapping(@NonNull org.eclipse.qvtd.pivot.qvtimperative.Mapping object) {
+		return visitRule(object);
+	}
+
+	public @Nullable IStepper visitMappingCall(@NonNull org.eclipse.qvtd.pivot.qvtimperative.MappingCall object) {
+		return visitOCLExpression(object);
+	}
+
+	public @Nullable IStepper visitMappingCallBinding(@NonNull org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding object) {
+		return visitElement(object);
+	}
+
+	public @Nullable IStepper visitMiddlePropertyAssignment(@NonNull org.eclipse.qvtd.pivot.qvtimperative.MiddlePropertyAssignment object) {
+		return visitPropertyAssignment(object);
+	}
+
+	public @Nullable IStepper visitMiddlePropertyCallExp(@NonNull org.eclipse.qvtd.pivot.qvtimperative.MiddlePropertyCallExp object) {
+		return visitOppositePropertyCallExp(object);
+	}
+
+	public @Nullable IStepper visitVariablePredicate(@NonNull org.eclipse.qvtd.pivot.qvtimperative.VariablePredicate object) {
+		return visitPredicate(object);
+	}
+}
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/NonStepper.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/NonStepper.java
new file mode 100644
index 000000000..5d90cf404
--- /dev/null
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/NonStepper.java
@@ -0,0 +1,36 @@
+/**
+ * <copyright>
+ * 
+ * Copyright (c) 2014 E.D.Willink and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *   E.D.Willink - Initial API and implementation
+ *
+ * </copyright>
+ */
+package org.eclipse.qvtd.debug.stepper;
+
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
+import org.eclipse.ocl.examples.debug.stepper.AbstractStepper;
+import org.eclipse.ocl.examples.debug.vm.evaluator.IRootVMEvaluationVisitor;
+import org.eclipse.ocl.examples.pivot.Element;
+
+public class NonStepper extends AbstractStepper
+{
+	public static @NonNull NonStepper INSTANCE = new NonStepper();
+	
+	@Override
+	public @Nullable Element isPostStoppable(@NonNull IRootVMEvaluationVisitor<?> rootVMEvaluationVisitor, @NonNull Element childElement, @Nullable Element parentElement) {
+		return null;
+	}
+
+	@Override
+	public boolean isPreStoppable(@NonNull IRootVMEvaluationVisitor<?> rootVMEvaluationVisitor, @NonNull Element element) {
+		return false;
+	}
+}
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/PrePostStepper.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/PrePostStepper.java
new file mode 100644
index 000000000..e6230d9a9
--- /dev/null
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/PrePostStepper.java
@@ -0,0 +1,36 @@
+/**
+ * <copyright>
+ * 
+ * Copyright (c) 2014 E.D.Willink and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *   E.D.Willink - Initial API and implementation
+ *
+ * </copyright>
+ */
+package org.eclipse.qvtd.debug.stepper;
+
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
+import org.eclipse.ocl.examples.debug.stepper.AbstractStepper;
+import org.eclipse.ocl.examples.debug.vm.evaluator.IRootVMEvaluationVisitor;
+import org.eclipse.ocl.examples.pivot.Element;
+
+public class PrePostStepper extends AbstractStepper
+{
+	public static @NonNull PrePostStepper INSTANCE = new PrePostStepper();
+	
+	@Override
+	public @Nullable Element isPostStoppable(@NonNull IRootVMEvaluationVisitor<?> rootVMEvaluationVisitor, @NonNull Element childElement, @Nullable Element parentElement) {
+		return childElement;
+	}
+
+	@Override
+	public boolean isPreStoppable(@NonNull IRootVMEvaluationVisitor<?> rootVMEvaluationVisitor, @NonNull Element element) {
+		return true;
+	}
+}
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/PreStepper.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/PreStepper.java
new file mode 100644
index 000000000..d46440304
--- /dev/null
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/PreStepper.java
@@ -0,0 +1,36 @@
+/**
+ * <copyright>
+ * 
+ * Copyright (c) 2014 E.D.Willink and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *   E.D.Willink - Initial API and implementation
+ *
+ * </copyright>
+ */
+package org.eclipse.qvtd.debug.stepper;
+
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
+import org.eclipse.ocl.examples.debug.stepper.AbstractStepper;
+import org.eclipse.ocl.examples.debug.vm.evaluator.IRootVMEvaluationVisitor;
+import org.eclipse.ocl.examples.pivot.Element;
+
+public class PreStepper extends AbstractStepper
+{
+	public static @NonNull PreStepper INSTANCE = new PreStepper();
+	
+	@Override
+	public @Nullable Element isPostStoppable(@NonNull IRootVMEvaluationVisitor<?> rootVMEvaluationVisitor, @NonNull Element childElement, @Nullable Element parentElement) {
+		return null;
+	}
+
+	@Override
+	public boolean isPreStoppable(@NonNull IRootVMEvaluationVisitor<?> rootVMEvaluationVisitor, @NonNull Element element) {
+		return true;
+	}
+}
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/QVTiStepperVisitor.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/QVTiStepperVisitor.java
new file mode 100644
index 000000000..51bf42e98
--- /dev/null
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/QVTiStepperVisitor.java
@@ -0,0 +1,80 @@
+/*******************************************************************************
+ * Copyright (c) 2014 E.D.Willink and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *   E.D.Willink - Initial API and implementation
+ *******************************************************************************/
+package org.eclipse.qvtd.debug.stepper;
+
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
+import org.eclipse.ocl.examples.debug.stepper.OCLStepperVisitor;
+import org.eclipse.ocl.examples.debug.stepper.PostStepper;
+import org.eclipse.ocl.examples.debug.vm.evaluator.IStepper;
+import org.eclipse.qvtd.pivot.qvtbase.Domain;
+import org.eclipse.qvtd.pivot.qvtbase.Predicate;
+import org.eclipse.qvtd.pivot.qvtbase.Transformation;
+import org.eclipse.qvtd.pivot.qvtcorebase.Assignment;
+import org.eclipse.qvtd.pivot.qvtcorebase.BottomPattern;
+import org.eclipse.qvtd.pivot.qvtcorebase.GuardPattern;
+import org.eclipse.qvtd.pivot.qvtcorebase.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
+import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
+
+public class QVTiStepperVisitor extends AbstractQVTimperativeStepperVisitor
+{
+	public static @NonNull OCLStepperVisitor INSTANCE = new QVTiStepperVisitor(QVTiStepperVisitor.class);
+
+	protected QVTiStepperVisitor(@NonNull Object context) {
+		super(context);
+	}
+
+	@Override
+	public @Nullable IStepper visitAssignment(@NonNull Assignment object) {
+		return PostStepper.INSTANCE;
+	}
+
+	@Override
+	public @Nullable IStepper visitBottomPattern(@NonNull BottomPattern object) {
+		return NonStepper.INSTANCE;
+	}
+
+	@Override
+	public @Nullable IStepper visitDomain(@NonNull Domain object) {
+		return NonStepper.INSTANCE;
+	}
+
+	@Override
+	public @Nullable IStepper visitGuardPattern(@NonNull GuardPattern object) {
+		return NonStepper.INSTANCE;
+	}
+
+	@Override
+	public @Nullable IStepper visitMapping(@NonNull Mapping object) {
+		return PreStepper.INSTANCE;
+	}
+
+	@Override
+	public @Nullable IStepper visitMappingCall(@NonNull MappingCall object) {
+		return NonStepper.INSTANCE;
+	}
+
+	@Override
+	public @Nullable IStepper visitPredicate(@NonNull Predicate object) {
+		return NonStepper.INSTANCE;
+	}
+
+	@Override
+	public @Nullable IStepper visitRealizedVariable(@NonNull RealizedVariable object) {
+		return NonStepper.INSTANCE;
+	}
+
+	@Override
+	public @Nullable IStepper visitTransformation(@NonNull Transformation object) {
+		return PrePostStepper.INSTANCE;
+	}
+}
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/vm/QVTiVMVirtualMachine.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/vm/QVTiVMVirtualMachine.java
index 40885df98..4854a19c9 100644
--- a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/vm/QVTiVMVirtualMachine.java
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/vm/QVTiVMVirtualMachine.java
@@ -14,7 +14,9 @@ package org.eclipse.qvtd.debug.vm;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.eclipse.emf.ecore.EObject;
 import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.ocl.examples.debug.vm.UnitLocation;
 import org.eclipse.ocl.examples.debug.vm.VMVirtualMachine;
 import org.eclipse.ocl.examples.debug.vm.VariableFinder;
@@ -22,17 +24,101 @@ import org.eclipse.ocl.examples.debug.vm.data.VMStackFrameData;
 import org.eclipse.ocl.examples.debug.vm.data.VMVariableData;
 import org.eclipse.ocl.examples.debug.vm.evaluator.IVMEvaluationEnvironment;
 import org.eclipse.ocl.examples.debug.vm.launching.DebuggableRunner;
-import org.eclipse.ocl.examples.pivot.NamedElement;
+import org.eclipse.ocl.examples.pivot.Constraint;
+import org.eclipse.ocl.examples.pivot.Element;
+import org.eclipse.ocl.examples.pivot.Feature;
 import org.eclipse.ocl.examples.pivot.Operation;
 import org.eclipse.ocl.examples.pivot.Parameter;
 import org.eclipse.ocl.examples.pivot.Root;
 import org.eclipse.ocl.examples.pivot.Type;
 import org.eclipse.qvtd.debug.core.QVTiDebugCore;
 import org.eclipse.qvtd.debug.core.QVTiEvaluationContext;
+import org.eclipse.qvtd.pivot.qvtbase.Domain;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
+import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 
 public class QVTiVMVirtualMachine extends VMVirtualMachine
 {
+	private static boolean appendElementSignature(@NonNull StringBuilder s, @Nullable EObject eObject) {
+        if (eObject instanceof Root) {
+        	return false;
+        }
+        else if (eObject instanceof org.eclipse.ocl.examples.pivot.Package) {
+        	if (appendElementSignature(s, eObject.eContainer())) {
+    	        s.append("::");
+        	}
+	        s.append(((org.eclipse.ocl.examples.pivot.Package)eObject).getName());        
+			return true;
+        }
+        else if (eObject instanceof Type) {
+        	if (appendElementSignature(s, eObject.eContainer())) {
+    	        s.append("::");
+        	}
+	        s.append(((Type)eObject).getName());
+			return true;
+        }
+        else if (eObject instanceof Mapping) {
+        	if (appendElementSignature(s, eObject.eContainer())) {
+    	        s.append("::");
+        	}
+	        s.append(((Mapping)eObject).getName());
+			return true;
+        }
+        else if (eObject instanceof Domain) {
+        	if (appendElementSignature(s, eObject.eContainer())) {
+    	        s.append("::");
+        	}
+	        s.append(((Domain)eObject).getName());
+			return true;
+        }
+        else if (eObject instanceof MappingCall) {
+        	if (appendElementSignature(s, eObject.eContainer())) {
+    	        s.append("::");
+        	}
+	        s.append(((MappingCall)eObject).getReferredMapping().getName());
+			return true;
+        }
+        else if (eObject instanceof Operation) {
+        	if (appendElementSignature(s, eObject.eContainer())) {
+    	        s.append("::");
+        	}
+	        Operation operation = (Operation)eObject;
+			s.append(operation.getName());        
+	        s.append("(");        
+	        boolean isFirst = true;;
+	        for (Parameter param : operation.getOwnedParameter()) {
+	            if (!isFirst) {
+	                s.append(", ");
+	            }
+	            Type type = param.getType();
+	            s.append(type.getName());            
+	            isFirst = false;
+	        }
+	        s.append(")");        
+			return true;
+        }
+        else if (eObject instanceof Feature) {
+        	if (appendElementSignature(s, eObject.eContainer())) {
+    	        s.append("::");
+        	}
+	        s.append(((Feature)eObject).getName());        
+			return true;
+        }
+        else if (eObject instanceof Constraint) {
+        	if (appendElementSignature(s, eObject.eContainer())) {
+    	        s.append("::");
+        	}
+	        s.append(((Constraint)eObject).getName());        
+			return true;
+        }
+        else if (eObject != null) {
+        	return appendElementSignature(s, eObject.eContainer());
+        }
+        else {
+        	return false;
+        }
+    }
+
 	public static @NonNull VMStackFrameData[] createStackFrame(List<UnitLocation> stack) {
 		List<VMStackFrameData> result = new ArrayList<VMStackFrameData>();
 		
@@ -50,15 +136,16 @@ public class QVTiVMVirtualMachine extends VMVirtualMachine
 	public VMStackFrameData createStackFrame(@NonNull UnitLocation location) {
 		return createStackFrame(location, true);
 	}
-	
+
 	private static @NonNull VMStackFrameData createStackFrame(@NonNull UnitLocation location, boolean includeVars) {
 		IVMEvaluationEnvironment<?> evalEnv = location.getEvalEnv();
 		Root module = location.getModule();
 		String moduleName = (module != null) ? module.getName() : "<null>"; //$NON-NLS-1$
 		
-		NamedElement operation = location.getOperation();
-		String operSignature = (operation != null) ? getElementSignature(operation)
-				: null; //MessageFormat.format("<{0}>", moduleName); //$NON-NLS-1$
+		Element element = location.getElement();
+		StringBuilder s = new StringBuilder();
+		appendElementSignature(s, element);
+		String operSignature = s.toString(); //MessageFormat.format("<{0}>", moduleName); //$NON-NLS-1$
 		
 		List<VMVariableData> vars = VariableFinder.getVariables(evalEnv);
 		VMStackFrameData vmStackFrame = new VMStackFrameData(evalEnv.getID(), location.getURI().toString(), moduleName, 
@@ -67,38 +154,6 @@ public class QVTiVMVirtualMachine extends VMVirtualMachine
 	}
 	
 	
-	private static String getElementSignature(NamedElement operation) {
-        StringBuilder buf = new StringBuilder();
-
-        buf.append(operation.getName());        
-        buf.append('(');
-        if (operation instanceof Operation) {
-	        boolean isFirst = true;;
-	        for (Parameter param : ((Operation)operation).getOwnedParameter()) {
-	            if (!isFirst) {
-	                buf.append(", ");
-	            }
-	            Type type = param.getType();
-	            buf.append(type.getName());            
-	            isFirst = false;
-	        }
-        }
-        else if (operation instanceof Mapping) {
-/*	        boolean isFirst = true;;
-	        for (Variable param : ((Mapping)operation).getAllVariables()) {
-	            if (!isFirst) {
-	                buf.append(", ");
-	            }
-	            Type type = param.getType();
-	            buf.append(type.getName());            
-	            isFirst = false;
-	        } */
-        }
-        buf.append(')');
-        
-        return buf.toString();
-    }
-	
 	public QVTiVMVirtualMachine(@NonNull DebuggableRunner runner, @NonNull QVTiEvaluationContext evaluationContext) {
 		super(runner, runner.createDebuggableAdapter(evaluationContext));
 	}