diff --git a/AlgebraicDataflowArchitectureModel/src/algorithms/MethodBodyGenerator.java b/AlgebraicDataflowArchitectureModel/src/algorithms/MethodBodyGenerator.java
index 2cef2f4..3298912 100644
--- a/AlgebraicDataflowArchitectureModel/src/algorithms/MethodBodyGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/algorithms/MethodBodyGenerator.java
@@ -8,9 +8,11 @@
 import code.ast.TypeDeclaration;
 import models.Edge;
 import models.Node;
+import models.algebra.Expression;
 import models.algebra.InvalidMessage;
 import models.algebra.ParameterizedIdentifierIsFutureWork;
 import models.algebra.Symbol;
+import models.algebra.Term;
 import models.algebra.UnificationFailed;
 import models.algebra.ValueUndefined;
 import models.dataConstraintModel.ChannelMember;
@@ -61,8 +63,14 @@
 						if (pushPull.getOptions().get(0) == PushPullValue.PUSH) {
 							// push
 							MethodDeclaration update = getUpdateMethod(dstType);
-							String curState = d.getChannelGenerator().deriveUpdateExpressionOf(out, CodeGenerator.pushAccessor).toImplementation();
-							String updateStatement = dstResourceName + " = " + curState + ";";
+							Expression updateExp = d.getChannelGenerator().deriveUpdateExpressionOf(out, CodeGenerator.pushAccessor);
+							String curState = updateExp.toImplementation();
+							String updateStatement;
+							if (updateExp instanceof Term && ((Term) updateExp).getSymbol().getImplOperatorType() == Symbol.Type.METHOD_WITH_SIDE_EFFECT) {
+								updateStatement = curState + ";";								
+							} else {
+								updateStatement = dstResourceName + " = " + curState + ";";
+							}
 							if (update.getBody() == null || !update.getBody().getStatements().contains(updateStatement)) {
 								update.addFirstStatement(updateStatement);
 							}
diff --git a/AlgebraicDataflowArchitectureModel/src/models/algebra/Symbol.java b/AlgebraicDataflowArchitectureModel/src/models/algebra/Symbol.java
index 37f32d7..6e1788d 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/algebra/Symbol.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/algebra/Symbol.java
@@ -66,7 +66,7 @@
 	}
 	
 	public boolean isMethod() {
-		return (operatorType == Type.METHOD);
+		return (operatorType == Type.METHOD || operatorType == Type.METHOD_WITH_SIDE_EFFECT);
 	}
 
 	public Symbol[] getInverses() {
@@ -102,7 +102,7 @@
 	}
 	
 	public boolean isImplMethod() {
-		return (implOperatorType == Type.METHOD);
+		return (implOperatorType == Type.METHOD || implOperatorType == Type.METHOD_WITH_SIDE_EFFECT);
 	}
 
 	public void setImplOperatorType(Type implOperatorType) {
@@ -134,7 +134,8 @@
 	public enum Type {
 		PREFIX,
 		INFIX,
-		METHOD
+		METHOD,
+		METHOD_WITH_SIDE_EFFECT
 	}
 	
 	public Memento createMemento() {
diff --git a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/DataConstraintModel.java b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/DataConstraintModel.java
index 732bdfd..e8b641e 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/DataConstraintModel.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/DataConstraintModel.java
@@ -25,7 +25,7 @@
 	public static final Symbol sub = new Symbol(Parser.SUB, 2, Symbol.Type.INFIX);
 	public static final Symbol div = new Symbol(Parser.DIV, 2, Symbol.Type.INFIX);
 	public static final Symbol minus = new Symbol(Parser.MINUS, 1);
-	public static final Symbol cons = new Symbol("cons", 2, Symbol.Type.PREFIX, "add", Symbol.Type.METHOD, new int[] {1, 0});
+	public static final Symbol cons = new Symbol("cons", 2, Symbol.Type.PREFIX, "add", Symbol.Type.METHOD_WITH_SIDE_EFFECT, new int[] {1, 0});
 	public static final Symbol head = new Symbol("head", 1, Symbol.Type.PREFIX, "head", Symbol.Type.METHOD);
 	public static final Symbol body = new Symbol("tail", 1, Symbol.Type.PREFIX, "tail", Symbol.Type.METHOD);
 	public static final Symbol cond = new Symbol("if", 3);