Reflection is a notion that naturally emerges from philosophy, mathematics, and sciences. In short, reflection is the ability of an entity to alter its own behaviour. This paper suggests that reflection is crucial to the development of complex and trustworthy software systems. We present RL, a reflective computational model that aims to support the development of a large-scale framework for modelling and manipulating structured data. We give the formal semantics for this computational model. We also share preliminary work on a proof-of-concept implementation of RL and discuss future work.