Gargoyle

Abstract: INTRODUCTION: Some Facts and Some Conjectures about Gargoyles 6 HUMAN GARGOYLES 46 ANIMAL GARGOYLES 80 GROTESQUE GARGOYLES 100 Notes 126 Gargoyle Sites to Visit 130 Acknowledgements 133 Selected Bibliography 134 Index 136

Abstract: Initially, I must comment tha t the name of our compiler language, Gargoyle, has no special significance. Its only justification is tha t it was intended to be humorous. There seem to be two very different trends in methods of writing compilers. The oldest, and the one which tends to give the fastest and best compilers, is to consider each compiler as a separate problem and to write them all in an assembly language. The more modern method is the syntax-directed compiler. There exist intermediate systems, but most of these tend toward the classical methods. There is no doubt that it is easier to write a compiler when one possesses a general syntax-directed compiler. However, these compilers have two drawbacks. One is tha t they are slow, the other tha t the object programs are not as good as could be hoped for. The reason for this is that the sphere of irffiuence of the expert programmer (and only such write compilers) is very restricted. He can juggle the syntax around a bit (thereby probably making the compiler even slower), but apart from this there is not much he can do. The user, of course, wants a very rapid compiler which produces programs that are better than the best handcoded ones. Nobody has so far been able to make such a compiler, but as the classical approach is the one which leads to a result which approximates the ideal best, all generally used compilers are of this type. The influence of the cost of the compilers is seen on the price of the computers using them. The way to produce better compilers easier seems, as usual, to be a compromise. The author 's view has been that one should exploit a formal syntax as far as possible, at the same time letting the programmer maintain complete control. The characteristic properties of syntax-directed compilers are their inherent recursiveness and their ability to backtrack when a faulty syntax analysis has been made.