getExpression
KVOpExpression kve = (KVOpExpression) getExpression();
KVOpExpression kve = (KVOpExpression) getExpression();
return (getExpression().equals(other.getExpression()));
return (getExpression().hashCode());
KVExpression kve = (KVExpression) getExpression();
obj.getExpression().
if (o.getExpression().contradicts(
other.getExpression()))