@Override
    void replaceChild(@SuppressWarnings("unused") Node oldChild, @SuppressWarnings("unused") Node newChild)
    {
        // Replace child
        for(ListIterator<PVar> i = this._var_.listIterator(); i.hasNext();)
        {
            if(i.next() == oldChild)
            {
                if(newChild != null)
                {
                    i.set((PVar) newChild);
                    newChild.parent(this);
                    oldChild.parent(null);
                    return;
                }

                i.remove();
                oldChild.parent(null);
                return;
            }
        }

        throw new RuntimeException("Not a child.");
    }