Rule-based assignment of comments to AST nodes in C++ programs

ABSTRACT

Comments are essential components of programming languages: they preserve the developer's intentions, help the maintainers to understand hidden concepts, and may act as a source of automatic documentation generation. However most of the software maintenance tools (refactorers, slicing and analyser tools) ignore them therefore they lose an important part of information about the software. One of the reasons why tools neglect comments is that there is no single well-defined location in the software's AST where to place them. The relationship between the program's control structure and the comments depend on code conventions and human habits. Our research -- part of a project to develop a software maintenance tool -- focuses on the code comprehension process of large legacy C++ projects and heavily utilize code comments. We evaluated the commenting behaviour used in large projects and categorized the major patterns. We found that these patterns are strongly correlating in a single project. In the paper we present a method to find the correct place of the comments in the AST-based on project-specific rules. We evaluate our method and test it against open source C++ projects.

References

1. Clang. http://clang.llvm.org/.
2. Libre Office. http://www.libreoffice.org/.
3. LLVM. http://llvm.org/.
4. Mozilla Firefox. http://www.mozilla.org/en-US/firefox.
5. V8 JavaScript Engine. http://code.google.com/p/v8/.
6. VirtualBox. https://www.virtualbox.org/.
7. I. F. Darwin. Java Cookbook. O'Reilly, Sebastopol, CA, 2004.
8. A. Köhler. Der C/C++-Projektbegleiter. dpunkt.verlag, 69115 Heidelberg, 2007.
9. E. T. Ray. Learning XML. O'Reilly, Sebastopol, CA, 2003.
10. P. Sommerlad, G. Zgraggen, T. Corbat, and L. Felber. Retaining comments when refactoring code. In Companion to the 23rd ACM SIGPLAN conference on Object-oriented programming systems languages and applications, OOPSLA Companion '08, pages 653--662, New York, NY, USA, 2008. ACM.
11. G. Sridhara, L. Pollock, and K. Vijay-Shanker. Generating parameter comments and integrating with method summaries. In Program Comprehension (ICPC), 2011 IEEE 19th International Conference on, pages 71--80, june 2011.
12. B. Stroustrup. The C++ Programming Language Special Edition. Addison-Wesley, Reading, MA, 2000.
13. L. Tan, D. Yuan, G. Krishna, and Y. Zhou./* icomment: bugs or bad comments? */. SIGOPS Oper. Syst. Rev., 41:145--158, October 2007.
14. L. Tan, Y. Zhou, and Y. Padioleau. acomment: mining annotations from comments and code to detect interrupt related concurrency bugs. In Proceeding of the 33rd International Conference on Software Engineering, ICSE '11, pages 11--20, New York, NY, USA, 2011. ACM.

Index Terms

• Social and professional topics

  • Professional topics

    • Management of computing and information systems

      • Software management

        • Software maintenance

• Software and its engineering

  • Software creation and management

    • Software post-development issues