CHAPTER A brief history of rules 3 Rules have been with us long before there were computers, the Ten Commandments and the Code of Hammurabi 1 being but two examples. Both these sets of rules attempted to collect in one location natural language statements of a comprehensive set of rules by which the behavior of a particular com- munity was to be governed. Since then, there has from time to time been conflict between, on the one hand, those who would make the law accessible only to a professional class specially trained in inter- preting the law and, on the other hand, those who would make the law accessible to all. Recently, the latter school of thought has prevailed, with initiatives such as the `Plain Language Law' 2 . 3.1 IMPLEMENTING RULES 3.1.1 Rules in program code Although some declarative programming languages have been developed--such as Prolog, SQL