A static debugger assists a programmer in finding potential errors in programs. The key to a static debugger is set-based analysis (SBA). Many authors have described formulations of SBA, but leave open gaps among that theory, its implementation, and its use for a particular purpose. An implementation needs to confront these practical issues. While some of the implementation proceeds directly from the formal description of the analysis, there is much fine detail in the code. With a series of reports, we intend to bridge the gap between theory and implementation. In this first report, we implement an analyzer for a simple, first-order functional language and show how to use the analysis in a static debugger.