Static Program Analyzers (SPA) are interactive tools that enhance program understanding during maintenance by answering queries about programs. Depending on the maintenance task in hand, SPAs must process different source programs and answer different types of program queries. Flexibility is, therefore, a desirable property of SPAs. In this paper, we describe a program query language, called PQL, that facilitates the design of flexible SPAs. PQL is a conceptual level, source language-independent notation to specify program queries and program views. In PQL, we can query global program design as well as search for detail code patterns. PQL queries are answered automatically by a query evaluation mechanism built into an SPA. Program design models and PQL form the core of an SPA conceptual model. We based the SPA's architecture on this conceptual model. By separating the conceptual model from the implementation decisions, we can design SPAs that are customizable to the needs of the mainte...

Software reengineering has been described as being "about as easy as reconstructing a pig from a sausage" [11]. But the development of program transformation theory, as embodied in the FermaT transformation system, has made this miraculous feat into a practical possibility. This paper describes the theory...