Conclusions
We think we have shown that it is possible to do acceptably good typesetting of mathematics on a phototypesetter, with an input language that is easy to learn and use and that satisfies many users' demands. Such a package can be implemented in short order, given a compiler-compiler and a decent typesetting program underneath.
Defining a language, and building a compiler for it with a compiler-compiler seems like the only sensible way to do business. Our experience with the use of a grammar and a compiler-compiler has been uniformly favorable. If we had written everything into code directly, we would have been locked into our original design. Furthermore, we would have never been sure where the exceptions and special cases were. But because we have a grammar, we can change our minds readily and still be reasonably sure that if a construction works in one place it will work everywhere.
AcknowledgementsWe are deeply indebted to J. F. Ossanna, the author of C TROFF , for his willingness to modify C TROFF to make our task easier and for his continuous assistance during the development of our program. We are also grateful to A. V. Aho for help with language theory, to S. C. Johnson for aid with the compiler-compiler, and to our early users A. V. Aho, S. I. Feldman, S. C. Johnson, R. W. Hamming, and M. D. McIlroy for their constructive criticisms.
References