Abstractions in Large Systems William G. Griswold, Member, IEEE, Morison I. Chen, Robert W. Bowdidge, Jenny L. Cabaniss, Van B. Nguyen, and J. David Morgenthaler Restructuring software to improve its design can lower software maintenance costs. One problem encountered during restructuring is formulating the new design. A meaning-preserving program restructuring tool with a star diagram manipulable ation can help a programmer redesign a program based on abstract data types. However, the transformational support required for meaning-preserving restructuring is costly to provide. Also, programmers encounter comprehension and recall difficulties in complex restructuring tasks. Consequently, transformations were replaced with visual and organizational aids that help a programmer to plan and carry out a complex restructuring. For example, a star diagram manipulation called trimming was added, which mimics the way that basic restructuring transformations affect the star diagram display, allow...
William G. Griswold, Morison I. Chen, Robert W. Bo