Lucid, a Nonprocedural Language with Iteration Lucid is a formal system in which programs can be written and proofs of programs carried out. The proofs are particularly easy to follow and straightforward to produce because the statements in a Lucid program are simply axioms from which the proof proceeds by (almost) conventional logical reasoning, with the help of a few axioms and rules of inference for the special Lucid functions. As a programming language, Lucid is unconventional because, among other things, the order of statements is irrelevant and assignment statements are equations. Nevertheless, Lucid programs need not look much different than iterative programs in a conventional structured programming language using assignment and conditional statements and loops. CACM July, 1977 Ashcrof, E. A. Wadge, W. W. program proving, formal systems, semantics, iteration, structured programming 5.21 5.24 CA770709 JB December 28, 1977 8:30 AM 2021 4 2943 2222 4 2943 2227 4 2943 2315 4 2943 2326 4 2943 2470 4 2943 2732 4 2943 2865 4 2943 2896 4 2943 2943 4 2943 3014 4 2943 3068 4 2943 3077 4 2943 3143 4 2943 1834 5 2943 2943 5 2943 2943 5 2943 2943 5 2943 3150 5 2943 2060 6 2943 2704 6 2943 2842 6 2943 2939 6 2943 2940 6 2943 2941 6 2943 2943 6 2943 3073 6 2943 3148 6 2943