Defmacro for C: Lightweight, Ad Hoc Code Generation

We describe the design and implementation of CGen, a C code generator with support for Common Lisp-style macro expansion. Our code generator supports the simple and ecient management of variants, ad hoc code generation to capture reoccurring patterns, composable abstractions as well as the implementation of embedded domain specic languages by using the Common Lisp macro system. We demonstrate the applicability of our approach by numerous examples from small scale convenience macros over embedded languages to real-world applications in high-performance computing.