diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/IExpressionVisitor.java b/AlgebraicDataflowArchitectureModel/src/code/ast/IExpressionVisitor.java
index bf2b64b..c8faa50 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/IExpressionVisitor.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/IExpressionVisitor.java
@@ -8,15 +8,15 @@
 import models.dataConstraintModel.JsonTerm;
 
 public interface IExpressionVisitor {
-	void visit(Term term);
+	String visit(Term term, String[] sideEffects);
 	
-	void visit(Field field);
+	String visit(Field field, String[] sideEffects);
 	
-	void visit(Constant constant);
+	String visit(Constant constant, String[] sideEffects);
 	
-	void visit(Variable variable);
+	String visit(Variable variable, String[] sideEffects);
 	
-	void visit(JsonTerm jsonTerm);
+	String visit(JsonTerm jsonTerm, String[] sideEffects);
 	
-	void visit(JsonAccessor jsonAccessor);
+	String visit(JsonAccessor jsonAccessor, String[] sideEffects);
 }
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/JavaImplementationVisitor.java b/AlgebraicDataflowArchitectureModel/src/generators/JavaImplementationVisitor.java
index e55f7e6..1b5ccb2 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/JavaImplementationVisitor.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/JavaImplementationVisitor.java
@@ -15,10 +15,8 @@
 public class JavaImplementationVisitor implements IExpressionVisitor {
 	private static int jsonCount = 0;
 	
-	private final String[] sideEffects = {};
-	
 	@Override
-	public void visit(Term term) {
+	public String visit(Term term, String[] sideEffects) {
 		int[] implParamOrder = term.getSymbol().getImplParamOrder();
 		if (term.getSymbol().isImplLambda()) {
 			String[] components = term.getSymbol().getImplName().split("->");
@@ -155,27 +153,27 @@
 	}
 	
 	@Override
-	public void visit(Field field) {
-		return new code.ast.FieldAccess(new code.ast.ThisExpression(), visit((Constant) field, sideEffects).toString());
+	public String visit(Field field, String[] sideEffects) {
+		return new code.ast.FieldAccess(new code.ast.ThisExpression(), visit((Constant) field, sideEffects)).toString();
 	}
 	
 	@Override
-	public void visit(Constant constant) {
+	public String visit(Constant constant, String[] sideEffects) {
 		if (constant.getSymbol().isImplGenerative()) {
 			String exp = constant.getSymbol().generate(constant.getType(), new Type[]{}, new String[]{}, new String[]{}, sideEffects);
 			return exp;
 		}
 		
-		return new code.ast.Constant(constant.getSymbol().getImplName());
+		return new code.ast.Constant(constant.getSymbol().getImplName()).toString();
 	}
 	
 	@Override
-	public void visit(Variable variable) {
-		return new code.ast.Variable(variable.getName());
+	public String visit(Variable variable, String[] sideEffects) {
+		return new code.ast.Variable(variable.getName()).toString();
 	}
 	
 	@Override
-	public void visit(JsonTerm jsonTerm) {
+	public String visit(JsonTerm jsonTerm, String[] sideEffects) {
 		String temp = "temp_json" + jsonCount;
 		jsonCount++;
 
@@ -198,7 +196,7 @@
 	}
 	
 	@Override
-	public void visit(JsonAccessor jsonAccessor) {
+	public String visit(JsonAccessor jsonAccessor, String[] sideEffects) {
 		if (jsonAccessor.getSymbol().equals(DataConstraintModel.dotParam)) {
 			return jsonAccessor.getChildren().get(0).accept(this, sideEffects) + "." + jsonAccessor.getSymbol().toImplementation() + "(" + jsonAccessor.getChildren().get(1).accept(this, sideEffects) + ")";
 		}
diff --git a/AlgebraicDataflowArchitectureModel/src/models/algebra/Constant.java b/AlgebraicDataflowArchitectureModel/src/models/algebra/Constant.java
index 8d68aec..cd1c8da 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/algebra/Constant.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/algebra/Constant.java
@@ -45,11 +45,11 @@
 	}
 	
 	public String toImplementation(String[] sideEffects) {
-		return accept(new JavaImplementationVisitor(), sideEffects).toString();
+		return accept(new JavaImplementationVisitor(), sideEffects);
 	}
 	
 	@Override
-	public void accept(IExpressionVisitor visitor) {
-		visitor.visit(this);
+	public String accept(IExpressionVisitor visitor, String[] sideEffects) {
+		return visitor.visit(this, sideEffects);
 	}
 }
diff --git a/AlgebraicDataflowArchitectureModel/src/models/algebra/Expression.java b/AlgebraicDataflowArchitectureModel/src/models/algebra/Expression.java
index b4115fe..43dba7f 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/algebra/Expression.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/algebra/Expression.java
@@ -34,7 +34,7 @@
 		return getSubTerms(Variable.class);
 	}
 	
-	public abstract void accept(IExpressionVisitor visitor);
+	public abstract String accept(IExpressionVisitor visitor, String[] sideEffects);
 	
 	/**
 	 * Get the implementation of this expression.
diff --git a/AlgebraicDataflowArchitectureModel/src/models/algebra/Field.java b/AlgebraicDataflowArchitectureModel/src/models/algebra/Field.java
index f988f2e..4b1858d 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/algebra/Field.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/algebra/Field.java
@@ -47,7 +47,7 @@
 	}
 	
 	@Override
-	public void accept(IExpressionVisitor visitor) {
-		visitor.visit(this);
+	public String accept(IExpressionVisitor visitor, String[] sideEffects) {
+		return visitor.visit(this, sideEffects);
 	}
 }
diff --git a/AlgebraicDataflowArchitectureModel/src/models/algebra/Term.java b/AlgebraicDataflowArchitectureModel/src/models/algebra/Term.java
index e1dda9f..cc91fd9 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/algebra/Term.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/algebra/Term.java
@@ -313,11 +313,11 @@
 	}
 	
 	public String toImplementation(String[] sideEffects) {
-		return accept(new JavaImplementationVisitor(), sideEffects).toString();
+		return accept(new JavaImplementationVisitor(), sideEffects);
 	}
 	
 	@Override
-	public void accept(IExpressionVisitor visitor) {
-		visitor.visit(this);
+	public String accept(IExpressionVisitor visitor, String[] sideEffects) {
+		return visitor.visit(this, sideEffects);
 	}
 }
diff --git a/AlgebraicDataflowArchitectureModel/src/models/algebra/Variable.java b/AlgebraicDataflowArchitectureModel/src/models/algebra/Variable.java
index 13cf8ab..a1c1dcc 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/algebra/Variable.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/algebra/Variable.java
@@ -89,7 +89,7 @@
 	}
 	
 	@Override
-	public void accept(IExpressionVisitor visitor) {
-		visitor.visit(this);
+	public String accept(IExpressionVisitor visitor, String[] sideEffects) {
+		return visitor.visit(this, sideEffects);
 	}
 }
diff --git a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonAccessor.java b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonAccessor.java
index 904693f..17668ff 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonAccessor.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonAccessor.java
@@ -206,12 +206,12 @@
 	}
 	
 	public String toImplementation(String[] sideEffects) {
-		return accept(new JavaImplementationVisitor(), sideEffects).toString();
+		return accept(new JavaImplementationVisitor(), sideEffects);
 	}
 	
 	@Override
-	public void accept(IExpressionVisitor visitor) {
-		visitor.visit(this);
+	public String accept(IExpressionVisitor visitor, String[] sideEffects) {
+		return visitor.visit(this, sideEffects);
 	}
 	
 	@Override
diff --git a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonTerm.java b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonTerm.java
index 02f3189..4606711 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonTerm.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonTerm.java
@@ -96,7 +96,7 @@
 	}
 	
 	@Override
-	public void accept(IExpressionVisitor visitor) {
-		visitor.visit(this);
+	public String accept(IExpressionVisitor visitor, String[] sideEffects) {
+		return visitor.visit(this, sideEffects);
 	}
 }