Geppetto: Enhancing Smalltalk’s Reflective Capabilities with Unanticipated Reflection

Reflection is an important tool to extend and modify the semantics or runtime of applications. However, lot of approaches to support reflection are based on up-front fully reflective or load-time based reflection mechanisms. Using these approaches, it is not possible to apply reflective techniques on running systems without stopping them, unless the system is fully reflection which is very costly. Because many applications and systems exist that cannot be halted and stopped but have to be always on and running, such as web applications, real-time systems or mobile systems, the ability to apply reflective features at runtime is a crucial and important property. Our solution to achieve this possibility is unanticipated reflection. With unanticipated reflection, we can design the MOP required for the problem we want to solve, introduce it in the language, activate the reflective mechanisms and possibly remove them once they are not necessary anymore at runtime, without halting the system or the application in which we want to apply and use the reflective mechanisms