Four Relational Programs

摘要

Relational programming is a style of programming in which entire relations are manipulated as data and in which programs are also considered relations. Extensive use is made of higher-order, finite and infinite relations and functions. This report demonstrates the relational programming language RPL by using it to develop four programs: (1) computing work frequencies from text; (2) minimizing deterministic finite state automata; (3) Gaussian elimination; and (4) a simple data processing example involving updating an employee file. Appendix A shows transcripts of executions of the programs on the Brown and Mitton interpreter. The reader is presumed to be familiar with RPL. for convenience, however, Appendix B contains the RPL grammar, and Appendix C describes the language accepted by the Brown and Mitton interpreter.