codemetre allows you to compare different versions of your software project, determining how and how much source files have changed. It currently recognizes both source code and comments from Ada, Bash shell, C, Eiffel, SQL, and more. It can also provide you with metrics on any single snapshot of your project.
SmartEiffel is the GNU Eiffel Compiler. It is intended to be a complete, though small and very fast, Eiffel compiler. The current distribution includes an Eiffel to C compiler, documentation tools, a pretty printer, and various other tools including an Eiffel debugger. It also includes a large library of classes distributed under the terms of the MIT/X Consortium License. Eiffel is an advanced object-oriented programming language that emphasizes the design and construction of high-quality and reusable software.