Approaches to Constructing Specifications

Abstract

In Chapter 14, we have studied the three-step approach to building formal specifications, but the approach only addresses the issue of how to express specifications in different formats; the question of how to create the architecture of specifications from scratch still remains unanswered. In this chapter we focus the discussion on this problem, and introduce two approaches to constructing specifications: top-down and middle-out. Each approach contains specific strategies for building specifications, and each strategy has its own features and may have different effects on the process of specification construction. The SOFL method does not restrict the use of these approaches, because different approaches can be effective to different problems. Since a pure bottom-up approach usually does not work well in practice, SOFL is not intended to support this kind of approach. For this reason, we do not give any detailed discussion on the bottom-up approach, although the related techniques for synthesizing lower level CDFDs are described when the middle-out approach is introduced in Section 15.2.