Programmable Syntax Macros

Abstract

Lisp has shown that a programmable syntax macro system acts as an adjunct to the compiler that gives the programmer important and powerful abstraction facilities not provided by the language. Unlike simple token substitution macros, such as are provided by CPP (the C preprocessor), syntax macros operate on Abstract Syntax Trees (ASTs). Programmable syntax macro systems have not yet been developed for syntactically rich languages such as C because rich concrete syntax requires the manual construction of syntactically valid program fragments, which is a tedious, difficult, and error prone process. Also, using two languages, one for writing the program, and one for writing macros, is another source of complexity. This research solves these problems by having the macro language be a minimal extension of the programming language, by introducing explicit code template operators into the macro language, and by using a type system to guarantee, at macro definition time, that all macros and mac..