Sub-method structural and behavioral reflection

Computational reflection is a fundamental mechanism in object oriented languages. Reflection has proved useful in many contexts, such as in the design of development environments, language extension, and the dynamic, unanticipated adaptation of running systems. We identify three problems with the current approach to reflection in object oriented languages: partial behavioral reflection needs to be anticipated, structural reflection is limited to the granularity of a method, and behavioral reflection cannot be applied to the whole system. To address these problems, we extend structural reflection to cover sub-method elements and present how sub-method structural reflection supports unanticipated partial behavioral reflection. We add the concept of context to represent meta-level execution and show how this allows behavioral reflection to be applied even to system classes. We describe an implementation in Smalltalk. Benchmarks validate the practicability of our approach. In addition, we present an experimental evaluation in which we show how the system is used for dynamic analysis. We realize dynamic feature analysis by annotating the sub-method structure of the system directly to denote features instead of recording full execution traces.