Marginal annotations and images comment the source code.
Links help the reader navigate through it, and find the documentation for a certain piece of code.
This makes programs easier to develop, read, understand, and thus reuse. The concept can also be applied easily to the area of computer-based learning, especially to computer science practicals. The project includes the implementation of a real-world development system, based on widespread existing tools and the HTML standard for structured documents. Moreover, those documents are essentially linear with no inherent support for navigation, e.g., to go from a function call to the module where it is defined, or to jump to that paragraph in the documentation where the algorithm behind a function is explained. Source code and documentation are created as structured hypermedia documents.