implement node visitors for the destructor node

src/main/java/de/hsrm/compiler/Klang/visitors/EvalVisitor.java

@@ -502,4 +502,10 @@ public class EvalVisitor implements Visitor<Value> {
     return null;
   }
 
+  @Override
+  public Value visit(DestructorCall e) {
+    // TODO Auto-generated method stub
+    return null;
+  }
+
 }

src/main/java/de/hsrm/compiler/Klang/visitors/GenASM.java

@@ -825,4 +825,10 @@ public class GenASM implements Visitor<Void> {
     return null;
   }
 
+  @Override
+  public Void visit(DestructorCall e) {
+    // TODO Auto-generated method stub
+    return null;
+  }
+
 }

src/main/java/de/hsrm/compiler/Klang/visitors/GetVars.java

@@ -265,4 +265,8 @@ class GetVars implements Visitor<Void> {
     return null;
   }
 
+  @Override
+  public Void visit(DestructorCall e) {
+    return null;
+  }
 }

src/main/java/de/hsrm/compiler/Klang/visitors/PrettyPrintVisitor.java

@@ -438,4 +438,10 @@ public class PrettyPrintVisitor implements Visitor<Void> {
     return null;
   }
 
+  @Override
+  public Void visit(DestructorCall e) {
+    ex.write("destroy " + e.name);
+    return null;
+  }
+
 }

src/main/java/de/hsrm/compiler/Klang/visitors/Visitor.java

@@ -48,4 +48,5 @@ public interface Visitor<R> {
     R visit(StructFieldAccessExpression e);
     R visit(ConstructorCall e);
     R visit(NullExpression e);
+    R visit(DestructorCall e);
 }