Software Plans A Multidimensional Approach for Fine-Grained Tangling of Concerns in Code

To date, research in separation of concerns has focused on the development of language abstractions having a syntax for encapsulating concerns and a semantics for automatically integrating them. These mechanisms are effective at separating concerns at the granularity of the abstraction but fail at a finer level of granularity. In this paper, we characterize the nature of concern interactions and argue that finegrained tangling is inevitable and cannot be addressed using encapsulation-based approaches. Instead, we present software plans, a language-independent, editor-based approach that allows concerns to be separately implemented and tangled in a principled way. Our approach is multidimensional in that orthogonal concerns are implemented in separate plans and fine-grained in that it can be used to separate concerns down to the character level. We also present Spotlight, a prototype editor that realizes the software plans approach.