Operational versus definitional: a perspective on programming paradigms

Various paradigms that support high-level programming are discussed independently of supporting languages. The paradigms are grouped according to their approach to problem solving. The operational approach describes step-by-step how to construct a solution. The demonstrational approach is a variation on it that illustrates the solution operationally for specific examples and lets the system generalize these example solutions for other cases. The definitional approach is different. It states properties about the solution to constrain it without describing how to compute it. These three approaches are viewed on a continuum from operational to definitional. A pure language solution to the problem of sorting a list into some linear order is presented for each paradigm.>