Validation of Code Unloading and error recovery in ROOT's new C++ Interpreter Cling

ROOT is the LHC physicists' common tool for data analysis. The main user interface is a C++ interpreter; physicists run, edit, and re-run code until it does what they want. A crucial part of re-running is the prior unloading of the code's old version. In this project, my job was to create a tool to validate the compiler representation (for example the AST, the included files and the lookup tables) of the code after unloading. To do so, I implemented two meta commands: the first one stores the state of the compiler, the second one compares the current state to the initial one stored.