Visualization of C++ Template Metaprograms

Template metaprograms have become an essential part of today’s C++ programs: with proper template definitions we can force the C++ compiler to execute algorithms at compilation time. Among the application areas of template metaprograms are the expression templates, static interface checking, code optimization with adaptation, language em-bedding and active libraries. Despite all of its already proven benefits and numerous successful applications there are surprisingly few tools for creating, supporting, and ana-lyzing C++ template metaprograms. As metaprograms are executed at compilation time they are even harder to under-stand. In this paper we present a code visualization tool, which is utilizing Templight, our previously developed C++ template metaprogram debugger. Using the tool it is pos-sible to visualize the instantiation chain of C++ templates and follow the execution of metaprograms. Various presen-tation layers, filtering of template instances and step-by-step replay of the instantiations are supported. Our tool can help to test, optimize, maintain C++ template metapro-grams, and can enhance their acceptance in the software industry. 1