diff --git a/AlgebraicDataflowArchitectureModel/src/simulator/Simulator.java b/AlgebraicDataflowArchitectureModel/src/simulator/Simulator.java
index 7528793..7e222cb 100644
--- a/AlgebraicDataflowArchitectureModel/src/simulator/Simulator.java
+++ b/AlgebraicDataflowArchitectureModel/src/simulator/Simulator.java
@@ -51,12 +51,12 @@
 				// root resource
 				Resource resource = new Resource(res);
 				curState.addResource(resource);
-				Expression initilValue = res.getInitialValue();
-				if (initilValue != null) {
-					if (initilValue instanceof Term) {
-						initilValue = ((Term) initilValue).reduce();
+				Expression initialValue = res.getInitialValue();
+				if (initialValue != null) {
+					if (initialValue instanceof Term) {
+						initialValue = ((Term) initialValue).reduce();
 					}
-					curState.updateResourceState(resource.getResourceIdentifier(), initilValue);
+					curState.updateResourceState(resource.getResourceIdentifier(), null, null, initialValue);
 				}
 			}
 		}
@@ -145,9 +145,12 @@
 	 */
 	private void fireEvent(final Event event, final SystemState curSystemState, final SystemState nextSystemState)
 			throws ParameterizedIdentifierIsFutureWork, ResolvingMultipleDefinitionIsFutureWork, InvalidMessage, UnificationFailed, ValueUndefined {
+		final ChannelMember[] outTarget = new ChannelMember[1];
+		final Variable[] outResVar = new Variable[1];
 		IResourceStateAccessor resouceStateAccessor = new IResourceStateAccessor() {
 			@Override
 			public Expression getCurrentStateAccessorFor(ChannelMember target, ChannelMember from) {
+				if (target == outTarget[0]) return outResVar[0];		// the current state of each output resource is not to be replaced with its value.
 				ResourceIdentifier resId = event.getResourceIdentifier(target.getResource());
 				Resource res = curSystemState.getResource(resId);
 				if (res == null) return null;
@@ -176,7 +179,9 @@
 			// For each output resource, calculate the next state.
 			for (ChannelMember out: channel.getOutputChannelMembers()) {
 				// Calculate the next state expression.
-				Expression nextResState = null; 
+				Expression nextResState = null;
+				outTarget[0] = out;
+				outResVar[0] = new Variable(channel.getChannelName() + "$" + out.getResource().toString() + "$this");		// A special variable to represent the current state of each output resource.
 				if (!event.isInput()) {
 					nextResState = channel.deriveUpdateExpressionOf(out, resouceStateAccessor).getKey();
 				} else {
@@ -189,18 +194,25 @@
 						nextResState = ((Term) nextResState).substitute((Variable) selExp, selestorAndVal.getValue());
 					}
 				}
-				if (nextResState instanceof Term) {
-					nextResState = ((Term) nextResState).reduce();
-				}
 				// Update the resource state.
 				ResourceIdentifier outResId = event.getOutputResourceIdentifier(out.getResource());
-				ResourceIdentifier updatedOutResId = nextSystemState.updateResourceState(outResId, nextResState);
-				while (updatedOutResId != null) {		// In addition to the target state, its descendants' states are also changed.
-					for (Event nextEvent: getNextEvents(updatedOutResId, curSystemState, nextSystemState)) {
-						fireEvent(nextEvent, curSystemState, nextSystemState);
+				Expression curResState = null;
+				if (curSystemState.getResource(outResId) != null) {
+					curResState = curSystemState.getResource(outResId).getState().getValue();
+				}
+				List<ResourceIdentifier> updatedOutResIds = nextSystemState.updateResourceState(outResId, outResVar[0], curResState, nextResState);
+				if (updatedOutResIds != null) {
+					Set<ResourceIdentifier> ancestors = new HashSet<>();
+					for (ResourceIdentifier updatedOutResId: updatedOutResIds) {
+						while (updatedOutResId != null && !ancestors.contains(updatedOutResId)) {		// In addition to the target state, its ancestors' states are also changed.
+							ancestors.add(updatedOutResId);
+							for (Event nextEvent: getNextEvents(updatedOutResId, curSystemState, nextSystemState)) {
+								fireEvent(nextEvent, curSystemState, nextSystemState);
+							}
+							if (channel.isNative()) break;		// To avoid multiple updates of the same resource.
+							updatedOutResId = (ResourceIdentifier) updatedOutResId.getParent();
+						}
 					}
-					if (channel.isNative()) break;		// To avoid multiple updates of the same resource.
-					updatedOutResId = (ResourceIdentifier) updatedOutResId.getParent();
 				}
 			}
 		} else if (channel.isNative()) {
diff --git a/AlgebraicDataflowArchitectureModel/src/simulator/SystemState.java b/AlgebraicDataflowArchitectureModel/src/simulator/SystemState.java
index c101792..a1a0806 100644
--- a/AlgebraicDataflowArchitectureModel/src/simulator/SystemState.java
+++ b/AlgebraicDataflowArchitectureModel/src/simulator/SystemState.java
@@ -75,19 +75,41 @@
 	 * update the state of a specified resource
 	 * 
 	 * @param resourceIdentifier a resource identifier to identify the resource
-	 * @param resStateValue a new state of the resource
-	 * @return
+	 * @param curResVar a variable to represent the current state of the resource (may be replaced with resCurStateVal)
+	 * @param resCurStateVal the value of the current state of the resource
+	 * @param resNextStateVal the value of the new state of the resource (may contain curResVar)
+	 * @return the identifier of the deepest resource created by this update.
 	 */
-	public ResourceIdentifier updateResourceState(ResourceIdentifier resourceIdentifier, Expression resStateValue) {
+	public List<ResourceIdentifier> updateResourceState(ResourceIdentifier resourceIdentifier, Variable curResVar, Expression resCurStateVal, Expression resNextStateVal) {
 		Type resType = resourceIdentifier.getResourceStateType();
+		if (resNextStateVal instanceof Term) {
+			Term termValue = (Term) resNextStateVal;
+			if (termValue.getSymbol().equals(DataConstraintModel.cond)) {
+				// If resNextStateVal is a conditional term, then calculates it here.
+				Expression condExp = termValue.getChild(0);
+				if (condExp instanceof Term) {
+					condExp = ((Term) condExp).substitute(curResVar, resCurStateVal);
+					condExp = ((Term) condExp).reduce();
+				}
+				List<Expression> condArgs = new ArrayList<>();
+				condArgs.add(condExp);
+				condArgs.add(termValue.getChild(1));
+				condArgs.add(termValue.getChild(2));
+				resNextStateVal = DataConstraintModel.cond.calculate(condArgs);
+				if (resNextStateVal != null) {
+					return updateResourceState(resourceIdentifier, curResVar, resCurStateVal, resNextStateVal);
+				}
+				return null;
+			}
+		}
 		if (resType != null && DataConstraintModel.typeList.isAncestorOf(resType)) {
-			if (resStateValue instanceof Constant) {
-			} else if (resStateValue instanceof ListTerm) {
-				ListTerm listValue = (ListTerm) resStateValue;
+			if (resNextStateVal instanceof Constant) {
+			} else if (resNextStateVal instanceof ListTerm) {
+				ListTerm listValue = (ListTerm) resNextStateVal;
 				Resource res = getResource(resourceIdentifier);
 				ResourceState state = res.getState();
 				if (state instanceof ListResourceState) {
-					ResourceIdentifier createdResource = null;
+					List<ResourceIdentifier> createdResources = new ArrayList<>();
 					((ListResourceState) state).clearChildStates();
 					for (int i = 0; i < listValue.size(); i++) {
 						Expression childExp = new Constant(Integer.toString(i), DataConstraintModel.typeInt);
@@ -104,19 +126,42 @@
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), 1, childResType);
 						}
 						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, listValue.get(i));
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, listValue.get(i));
 						((ListResourceState) state).addChildState(childInfo.getKey());
-						createdResource = childInfo.getValue();
+						createdResources.addAll(childInfo.getValue());
 					}
-					return createdResource;
-				} else {
-					return resourceIdentifier;
+					return createdResources;
 				}
-			} else if (resStateValue instanceof Term) {
-				Term listValue = (Term) resStateValue;
+				return null;
+			} else if (resNextStateVal instanceof Term) {
+				Term listValue = (Term) resNextStateVal;
 				if (listValue.getSymbol().equals(DataConstraintModel.append)) {
+					List<ResourceIdentifier> createdResources = new ArrayList<>();
 					Resource res = getResource(resourceIdentifier);
 					ResourceState state = res.getState();
+					if (listValue.getChild(0) instanceof Term) {
+						if (listValue.getChild(0) instanceof Constant && ((Constant) listValue.getChild(0)).getSymbol().equals(DataConstraintModel.nil)) {
+							// If the child list is nil.
+							ResourceState parentState = res.getParent().getState();
+							ResourceState newState = new ListResourceState();
+							if (parentState instanceof CompositeResourceState) {
+								((CompositeResourceState) parentState).replaceChildState(state, newState);
+							}
+							state = newState;
+							res.changeState(state);
+						} else {
+							Expression childList = ((Term) listValue.getChild(0)).reduce();
+							if (childList instanceof ListTerm) {
+								// If the child list is a list literal.
+								List<ResourceIdentifier> childInfo = updateResourceState(resourceIdentifier, curResVar, resCurStateVal, childList);		// one more recursion.
+								if (childInfo != null) createdResources.addAll(childInfo);
+							} else if (childList instanceof Term) {
+								// There may or may not be the current state of the resource (curResVar) under the child.
+								List<ResourceIdentifier> childInfo = updateResourceState(resourceIdentifier, curResVar, resCurStateVal, listValue.getChild(0));
+								createdResources.addAll(childInfo);
+							}
+						}
+					}
 					Expression childExp = null;
 					if (state instanceof ListResourceState) {
 						childExp = new Constant(Integer.toString(((ListResourceState) state).getChildStates().size()), DataConstraintModel.typeInt);
@@ -144,19 +189,20 @@
 						childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), 1, childResType);
 					}
 					ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
-					Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, listValue.getChild(1));
+					Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, listValue.getChild(1));
 					((ListResourceState) state).addChildState(childInfo.getKey());
-					return childInfo.getValue();
+					createdResources.addAll(childInfo.getValue());
+					return createdResources;
 				}
 			}
 		} else if (resType != null && DataConstraintModel.typeMap.isAncestorOf(resType)) {
-			if (resStateValue instanceof Constant) {
-			} else if (resStateValue instanceof JsonTerm) {
-				JsonTerm mapValue = (JsonTerm) resStateValue;
+			if (resNextStateVal instanceof Constant) {
+			} else if (resNextStateVal instanceof JsonTerm) {
+				JsonTerm mapValue = (JsonTerm) resNextStateVal;
 				Resource res = getResource(resourceIdentifier);
 				ResourceState state = res.getState();
 				if (state instanceof MapResourceState) {
-					ResourceIdentifier createdResource = null;
+					List<ResourceIdentifier> createdResources = new ArrayList<>();
 					((MapResourceState) state).clearChildStates();
 					for (String key: mapValue.keySet()) {
 						Expression childExp = new Constant(key, DataConstraintModel.typeString);
@@ -173,19 +219,18 @@
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), 1, childResType);
 						}
 						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, mapValue.get(key));
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, mapValue.get(key));
 						((MapResourceState) state).addChildState(key, childInfo.getKey());
-						createdResource = childInfo.getValue();
+						createdResources.addAll(childInfo.getValue());
 					}
-					return createdResource;
-				} else {
-					return resourceIdentifier;
+					return createdResources;
 				}
-			} else if (resStateValue instanceof MapTerm) {
-				MapTerm mapValue = (MapTerm) resStateValue;
+				return null;
+			} else if (resNextStateVal instanceof MapTerm) {
+				MapTerm mapValue = (MapTerm) resNextStateVal;
 				Resource res = getResource(resourceIdentifier);
 				ResourceState state = res.getState();
-				ResourceIdentifier createdResource = null;
+				List<ResourceIdentifier> createdResources = new ArrayList<>();
 				for (String key: mapValue.keySet()) {
 					Expression childExp = new Constant(key, DataConstraintModel.typeString);
 					ResourceHierarchy childResourceHierarchy = null;
@@ -201,18 +246,46 @@
 						childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), 1, childResType);
 					}
 					ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
-					Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, mapValue.get(key));
+					Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, mapValue.get(key));
 					((MapResourceState) state).addChildState(key, childInfo.getKey());
-					createdResource = childInfo.getValue();
+					createdResources.addAll(childInfo.getValue());
 				}
-				return createdResource;
-			} else if (resStateValue instanceof Term) {
-				Term mapValue = (Term) resStateValue;
+				return createdResources;
+			} else if (resNextStateVal instanceof Term) {
+				Term mapValue = (Term) resNextStateVal;
 				if (mapValue.getSymbol().equals(DataConstraintModel.insert)) {
-					Expression childExp = mapValue.getChild(1);
-					if (childExp instanceof Constant) {
+					List<ResourceIdentifier> createdResources = new ArrayList<>();
+					Expression childKeyExp = mapValue.getChild(1);
+					if (childKeyExp instanceof Term) {
+						childKeyExp = ((Term) childKeyExp).substitute(curResVar, resCurStateVal);
+						childKeyExp = ((Term) childKeyExp).reduce();
+					}
+					if (childKeyExp instanceof Constant) {
 						Resource res = getResource(resourceIdentifier);
 						ResourceState state = res.getState();
+						if (mapValue.getChild(0) instanceof Term) {
+							if (mapValue.getChild(0) instanceof Constant && ((Constant) mapValue.getChild(0)).getSymbol().equals(DataConstraintModel.nil)) {
+								// If the child map is nil.
+								ResourceState parentState = res.getParent().getState();
+								ResourceState newState = new MapResourceState();
+								if (parentState instanceof CompositeResourceState) {
+									((CompositeResourceState) parentState).replaceChildState(state, newState);
+								}
+								state = newState;
+								res.changeState(state);
+							} else {
+								Expression childMap = ((Term) mapValue.getChild(0)).reduce();
+								if (childMap instanceof MapTerm) {
+									// If the child map is a map literal.
+									List<ResourceIdentifier> childInfo = updateResourceState(resourceIdentifier, curResVar, resCurStateVal, childMap);	// one more recursion
+									createdResources.addAll(childInfo);
+								} else if (childMap instanceof Term) {
+									// There may or may not be the current state of the resource (curResVar) under the child.
+									List<ResourceIdentifier> childInfo = updateResourceState(resourceIdentifier, curResVar, resCurStateVal, mapValue.getChild(0));
+									createdResources.addAll(childInfo);
+								}
+							}
+						}
 						if (state instanceof PrimitiveResourceState && ((PrimitiveResourceState) state).getValue().getSymbol().equals(DataConstraintModel.nil)) {
 							// If the value of state is nil.
 							ResourceState parentState = res.getParent().getState();
@@ -235,22 +308,23 @@
 							}
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), 1, childResType);
 						}
-						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
-						String childId = ((Constant) childExp).toString();
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, mapValue.getChild(2));
+						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childKeyExp, childResourceHierarchy);
+						String childId = ((Constant) childKeyExp).toString();
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, mapValue.getChild(2));
 						((MapResourceState) state).addChildState(childId, childInfo.getKey());
-						return childInfo.getValue();
+						createdResources.addAll(childInfo.getValue());
+						return createdResources;
 					}
 				}
 			}
 		} else if (resType != null && DataConstraintModel.typeJson.isAncestorOf(resType)) {
-			if (resStateValue instanceof Constant) {
-			} else if (resStateValue instanceof JsonTerm) {
-				JsonTerm jsonValue = (JsonTerm) resStateValue;
+			if (resNextStateVal instanceof Constant) {
+			} else if (resNextStateVal instanceof JsonTerm) {
+				JsonTerm jsonValue = (JsonTerm) resNextStateVal;
 				Resource res = getResource(resourceIdentifier);
 				ResourceState state = res.getState();
 				if (state instanceof JsonResourceState) {
-					ResourceIdentifier createdResource = null;
+					List<ResourceIdentifier> createdResources = new ArrayList<>();
 					for (String key: jsonValue.keySet()) {
 						String memberName = key.replace("\"", "");
 						ResourceHierarchy childResourceHierarchy = null;
@@ -270,27 +344,26 @@
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), memberName, childResType);
 						}
 						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, memberName, childResourceHierarchy);
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, jsonValue.get(key));
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, jsonValue.get(key));
 						ResourceState childState = childInfo.getKey();
 						if (res.getChildrenMap() != null && res.getChildrenMap().get(memberName) != null) {
 							res.getChildrenMap().get(memberName).changeState(childState);
 						}
 						((JsonResourceState) state).addChildState(memberName, childState);
-						createdResource = childInfo.getValue();
+						createdResources.addAll(childInfo.getValue());
 					}
-					return createdResource;
-				} else {
-					return resourceIdentifier;
+					return createdResources;
 				}
-			} else if (resStateValue instanceof Term) {
-				Term jsonValue = (Term) resStateValue;
+				return null;
+			} else if (resNextStateVal instanceof Term) {
+				Term jsonValue = (Term) resNextStateVal;
 				Resource res = getResource(resourceIdentifier);
 				ResourceState state = res.getState();
-				ResourceIdentifier createdResource = null;
+				List<ResourceIdentifier> createdResources = new ArrayList<>();
 				while (jsonValue.getSymbol().equals(DataConstraintModel.addMember)) {
-					Expression childExp = jsonValue.getChild(1);
-					if (childExp instanceof Constant) {
-						String memberName = ((Constant) childExp).getSymbol().getName().replace("\"", "");
+					Expression childKeyExp = jsonValue.getChild(1);
+					if (childKeyExp instanceof Constant) {
+						String memberName = ((Constant) childKeyExp).getSymbol().getName().replace("\"", "");
 						ResourceHierarchy childResourceHierarchy = null;
 						for (ResourceHierarchy childRes: resourceIdentifier.getResourceHierarchy().getChildren()) {
 							if (childRes.getResourceName().equals(memberName)) {
@@ -308,42 +381,50 @@
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), memberName, childResType);
 						}
 						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, memberName, childResourceHierarchy);
-						String childId = ((Constant) childExp).toString();
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, jsonValue.getChild(2));
+						String childId = ((Constant) childKeyExp).toString();
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, jsonValue.getChild(2));
 						((JsonResourceState) state).addChildState(childId, childInfo.getKey());
-						createdResource = childInfo.getValue();
+						createdResources.addAll(childInfo.getValue());
 					}
 					if (!(jsonValue.getChild(0) instanceof Term)) break;
 					jsonValue = (Term) jsonValue.getChild(0);
 				}
-				return createdResource;
+				return createdResources;
 			}
 		} else {
-			if (resStateValue instanceof Constant) {
+			if (curResVar != null && resCurStateVal != null) {
+				if (resNextStateVal instanceof Term) {
+					resNextStateVal = ((Term) resNextStateVal).substitute(curResVar, resCurStateVal);
+					resNextStateVal = ((Term) resNextStateVal).reduce();
+				}
+			}
+			if (resNextStateVal instanceof Constant) {
 				Resource res = getResource(resourceIdentifier);
 				ResourceState state = null;
 				if (res != null) {
 					state = res.getState();
-					((PrimitiveResourceState) state).setValue((Constant) resStateValue);
+					((PrimitiveResourceState) state).setValue((Constant) resNextStateVal);
 				} else {
 					ResourceIdentifier parentResId = (ResourceIdentifier) resourceIdentifier.getParent();
 					Type parentResType = parentResId.getResourceStateType();
 					if (parentResType != null && DataConstraintModel.typeList.isAncestorOf(parentResType)) {
 					} else if (parentResType != null && DataConstraintModel.typeMap.isAncestorOf(parentResType)) {
 						JsonResourceState parentState = (JsonResourceState) getResource(parentResId).getState();
-						parentState.addChildState(((Constant) resourceIdentifier.getLastParam()).toString(), new PrimitiveResourceState((Constant) resStateValue));
+						parentState.addChildState(((Constant) resourceIdentifier.getLastParam()).toString(), new PrimitiveResourceState((Constant) resNextStateVal));
 					} else if (parentResType != null && DataConstraintModel.typeJson.isAncestorOf(parentResType)) {
 						JsonResourceState parentState = (JsonResourceState) getResource(parentResId).getState();
-						parentState.addChildState("\"" + resourceIdentifier.getLeafResourceName() + "\"", new PrimitiveResourceState((Constant) resStateValue));
+						parentState.addChildState("\"" + resourceIdentifier.getLeafResourceName() + "\"", new PrimitiveResourceState((Constant) resNextStateVal));
 					}
 				}
-				return resourceIdentifier;
+				List<ResourceIdentifier> updatedResources = new ArrayList<>();
+				updatedResources.add(resourceIdentifier);
+				return updatedResources;
 			}
 		}
-		return resourceIdentifier;
+		return null;
 	}
 
-	public Map.Entry<ResourceState, ResourceIdentifier> createResourceState(ResourceIdentifier resourceIdentifier, Expression resStateValue) {
+	public Map.Entry<ResourceState, List<ResourceIdentifier>> createResourceState(ResourceIdentifier resourceIdentifier, Variable curResVar, Expression resCurStateVal, Expression resStateValue) {
 		Type resType = resourceIdentifier.getResourceStateType();
 		if (resType == null && resStateValue instanceof Term) {
 			resType = ((Term) resStateValue).getType();
@@ -355,7 +436,7 @@
 				} else if (resStateValue instanceof ListTerm) {
 					ListTerm listValue = (ListTerm) resStateValue;
 					ListResourceState state = new ListResourceState();
-					Map.Entry<ResourceState, ResourceIdentifier> createInfo = null;
+					Map.Entry<ResourceState, List<ResourceIdentifier>> createInfo = new AbstractMap.SimpleEntry<>(null, new ArrayList<>());
 					for (int i = 0; i < listValue.size(); i++) {
 						Expression childExp = new Constant(Integer.toString(i), DataConstraintModel.typeInt);
 						ResourceHierarchy childResourceHierarchy = null;
@@ -371,15 +452,37 @@
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), 1, childResType);
 						}
 						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, listValue.get(i));
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, listValue.get(i));
 						state.addChildState(childInfo.getKey());
-						createInfo = new AbstractMap.SimpleEntry<>(state, childInfo.getValue());
+						createInfo.getValue().addAll(childInfo.getValue());
+						createInfo = new AbstractMap.SimpleEntry<>(state, createInfo.getValue());
 					}
 					return createInfo;
 				} else if (resStateValue instanceof Term) {
 					Term listValue = (Term) resStateValue;
 					if (listValue.getSymbol().equals(DataConstraintModel.append)) {
+						List<ResourceIdentifier> createdResources = new ArrayList<>();
 						ListResourceState state = new ListResourceState();
+						if (listValue.getChild(0) instanceof Term) {
+							if (listValue.getChild(0) instanceof Constant && ((Constant) listValue.getChild(0)).getSymbol().equals(DataConstraintModel.nil)) {
+								// If the child list is nil.
+							} else {
+								Expression childList = ((Term) listValue.getChild(0));
+								childList = ((Term) childList).substitute(curResVar, resStateValue);
+								childList = ((Term) childList).reduce();
+								if (childList instanceof ListTerm) {
+									// If the child list is a list literal.
+									Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(resourceIdentifier, curResVar, resCurStateVal, childList);		// one more recursion.
+									state = (ListResourceState) childInfo.getKey();
+									if (childInfo != null) createdResources.addAll(childInfo.getValue());
+								} else if (childList instanceof Term) {
+									// If the child list is a list term.
+									Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(resourceIdentifier, curResVar, resCurStateVal, listValue.getChild(0));
+									state = (ListResourceState) childInfo.getKey();
+									createdResources.addAll(childInfo.getValue());
+								}
+							}
+						}
 						Expression childExp = new Constant(Integer.toString(((ListResourceState) state).getChildStates().size()), DataConstraintModel.typeInt);
 						ResourceHierarchy childResourceHierarchy = null;
 						if (resourceIdentifier.getResourceHierarchy().getChildren() != null && resourceIdentifier.getResourceHierarchy().getChildren().size() > 0) {
@@ -394,9 +497,10 @@
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), 1, childResType);
 						}
 						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, listValue.getChild(1));
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, listValue.getChild(1));
 						state.addChildState(childInfo.getKey());
-						return new AbstractMap.SimpleEntry<>(state, childInfo.getValue());
+						createdResources.addAll(childInfo.getValue());
+						return new AbstractMap.SimpleEntry<>(state, createdResources);
 					}
 				}
 			} else if (DataConstraintModel.typeMap.isAncestorOf(resType)) {
@@ -404,7 +508,7 @@
 				} else if (resStateValue instanceof JsonTerm) {
 					JsonTerm mapValue = (JsonTerm) resStateValue;
 					MapResourceState state = new MapResourceState();
-					Map.Entry<ResourceState, ResourceIdentifier> createInfo = null;
+					Map.Entry<ResourceState, List<ResourceIdentifier>> createInfo = new AbstractMap.SimpleEntry<>(null, new ArrayList<>());
 					for (String key: mapValue.keySet()) {
 						Expression childExp = new Constant(key, DataConstraintModel.typeString);
 						ResourceHierarchy childResourceHierarchy = null;
@@ -420,15 +524,16 @@
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), 1, childResType);
 						}
 						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, mapValue.get(key));
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, mapValue.get(key));
 						state.addChildState(key, childInfo.getKey());
-						createInfo = new AbstractMap.SimpleEntry<>(state, childInfo.getValue());
+						createInfo.getValue().addAll(childInfo.getValue());
+						createInfo = new AbstractMap.SimpleEntry<>(state, createInfo.getValue());
 					}
 					return createInfo;
 				} else if (resStateValue instanceof MapTerm) {
 					MapTerm mapValue = (MapTerm) resStateValue;
 					MapResourceState state = new MapResourceState();
-					Map.Entry<ResourceState, ResourceIdentifier> createInfo = null;
+					Map.Entry<ResourceState, List<ResourceIdentifier>> createInfo = new AbstractMap.SimpleEntry<>(null, new ArrayList<>());
 					for (String key: mapValue.keySet()) {
 						Expression childExp = new Constant(key, DataConstraintModel.typeString);
 						ResourceHierarchy childResourceHierarchy = null;
@@ -444,9 +549,10 @@
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), 1, childResType);
 						}
 						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, mapValue.get(key));
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, mapValue.get(key));
 						state.addChildState(key, childInfo.getKey());
-						createInfo = new AbstractMap.SimpleEntry<>(state, childInfo.getValue());
+						createInfo.getValue().addAll(childInfo.getValue());
+						createInfo = new AbstractMap.SimpleEntry<>(state, createInfo.getValue());
 					}
 					return createInfo;
 				} else if (resStateValue instanceof Term) {
@@ -454,7 +560,28 @@
 					if (mapValue.getSymbol().equals(DataConstraintModel.insert)) {
 						Expression childExp = mapValue.getChild(1);
 						if (childExp instanceof Constant) {
+							List<ResourceIdentifier> createdResources = new ArrayList<>();
 							MapResourceState state = new MapResourceState();
+							if (mapValue.getChild(0) instanceof Term) {
+								if (mapValue.getChild(0) instanceof Constant && ((Constant) mapValue.getChild(0)).getSymbol().equals(DataConstraintModel.nil)) {
+									// If the child list is nil.
+								} else {
+									Expression childMap = ((Term) mapValue.getChild(0));
+									childMap = ((Term) childMap).substitute(curResVar, resStateValue);
+									childMap = ((Term) childMap).reduce();
+									if (childMap instanceof MapTerm) {
+										// If the child map is a map literal.
+										Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(resourceIdentifier, curResVar, resCurStateVal, childMap);	// one more recursion.
+										state = (MapResourceState) childInfo.getKey();
+										if (childInfo != null) createdResources.addAll(childInfo.getValue());
+									} else if (childMap instanceof Term) {
+										// If the child map is a map term.
+										Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(resourceIdentifier, curResVar, resCurStateVal, mapValue.getChild(0));
+										state = (MapResourceState) childInfo.getKey();
+										createdResources.addAll(childInfo.getValue());
+									}
+								}
+							}
 							ResourceHierarchy childResourceHierarchy = null;
 							if (resourceIdentifier.getResourceHierarchy().getChildren() != null && resourceIdentifier.getResourceHierarchy().getChildren().size() > 0) {
 								childResourceHierarchy = resourceIdentifier.getResourceHierarchy().getChildren().iterator().next();
@@ -469,9 +596,10 @@
 							}
 							ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, childExp, childResourceHierarchy);
 							String childId = ((Constant) childExp).toString();
-							Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, mapValue.getChild(2));
+							Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, mapValue.getChild(2));
 							state.addChildState(childId, childInfo.getKey());
-							return new AbstractMap.SimpleEntry<>(state, childInfo.getValue());
+							createdResources.addAll(childInfo.getValue());
+							return new AbstractMap.SimpleEntry<>(state, createdResources);
 						}
 					}
 				}
@@ -480,7 +608,7 @@
 				} else if (resStateValue instanceof JsonTerm) {
 					JsonTerm jsonValue = (JsonTerm) resStateValue;
 					JsonResourceState state = new JsonResourceState();
-					Map.Entry<ResourceState, ResourceIdentifier> createInfo = null;
+					Map.Entry<ResourceState, List<ResourceIdentifier>> createInfo = new AbstractMap.SimpleEntry<>(null, new ArrayList<>());
 					for (String key: jsonValue.keySet()) {
 						String memberName = key.replace("\"", "");
 						ResourceHierarchy childResourceHierarchy = null;
@@ -500,20 +628,21 @@
 							childResourceHierarchy = new ResourceHierarchy(resourceIdentifier.getResourceHierarchy(), memberName, childResType);
 						}
 						ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, memberName, childResourceHierarchy);
-						Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, jsonValue.get(key));
+						Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, jsonValue.get(key));
 						ResourceState childState = childInfo.getKey();
 						Resource res = getResource(resourceIdentifier);
 						if (res != null && res.getChildrenMap() != null && res.getChildrenMap().get(memberName) != null) {
 							res.getChildrenMap().get(memberName).changeState(childState);
 						}
 						state.addChildState(memberName, childState);
-						createInfo = new AbstractMap.SimpleEntry<>(state, childInfo.getValue());
+						createInfo.getValue().addAll(childInfo.getValue());
+						createInfo = new AbstractMap.SimpleEntry<>(state, createInfo.getValue());
 					}
 					return createInfo;
 				} else if (resStateValue instanceof Term) {
 					Term jsonValue = (Term) resStateValue;
 					JsonResourceState state = new JsonResourceState();
-					Map.Entry<ResourceState, ResourceIdentifier> createInfo = null;
+					Map.Entry<ResourceState, List<ResourceIdentifier>> createInfo = new AbstractMap.SimpleEntry<>(null, new ArrayList<>());
 					while (jsonValue.getSymbol().equals(DataConstraintModel.addMember)) {
 						Expression childExp = jsonValue.getChild(1);
 						if (childExp instanceof Constant) {
@@ -536,9 +665,10 @@
 							}
 							ResourceIdentifier childResourceIdentifier = new ResourceIdentifier(resourceIdentifier, memberName, childResourceHierarchy);
 							String childId = ((Constant) childExp).toString();
-							Map.Entry<ResourceState, ResourceIdentifier> childInfo = createResourceState(childResourceIdentifier, jsonValue.getChild(2));
+							Map.Entry<ResourceState, List<ResourceIdentifier>> childInfo = createResourceState(childResourceIdentifier, curResVar, resCurStateVal, jsonValue.getChild(2));
 							state.addChildState(childId, childInfo.getKey());
-							createInfo =  new AbstractMap.SimpleEntry<>(state, childInfo.getValue());
+							createInfo.getValue().addAll(childInfo.getValue());
+							createInfo = new AbstractMap.SimpleEntry<>(state, createInfo.getValue());
 						}
 						if (!(jsonValue.getChild(0) instanceof Term)) break;
 						jsonValue = (Term) jsonValue.getChild(0);
@@ -556,7 +686,9 @@
 			} else {
 				state = new PrimitiveResourceState((Constant) resStateValue);
 			}
-			return new AbstractMap.SimpleEntry<>(state, resourceIdentifier);
+			List<ResourceIdentifier> updatedResources = new ArrayList<>();
+			updatedResources.add(resourceIdentifier);
+			return new AbstractMap.SimpleEntry<>(state, updatedResources);
 		}
 		return null;
 	}