A SYNTAX-ORIENTED COMPILER FOR LANGUAGES WHOSE SYNTAX IS EXPRESSIBLE IN BACKUS NORMAL FORM, AND SOME PROPOSED EXTENSIONS THERETO

摘要

This paper discusses a syntax-oriented compiler for languages with a context-free syntax expressed in Backus Normal Form. The technique discussed is applicable to an iterated compilation process, where each phase of the compilation generates the rules of syntax required for the next phase of the compilation. Complete flow charts are included for the major processors; these flow charts are essentially machine-independent. Also included is a discussion of the extensions required which allow the compilation technique to be extended to context-dependent syntax, although a non-terminating compilation may result in certain cases if these extensions are included. The general technique is therefore not only shown to be extendable, but is also shown to facilitate the comparison of languages, since the idiosyncracies of individual compilers can be eliminated from the comparison.