1. When and why was Cling developed?

Cling was first released in 2014 as the interactive, C++ interpreter in ROOT. ROOT is an open-source program written primarily in C++, developed by research groups in high-energy physics including CERN, FERMILAB and Princeton. ROOT is nowadays used by most high-energy physics experiments. CERN is an European research organization that operates the largest particle physics laboratory in the world. Its experiments collect petabytes of data per year to be serialized, analyzed, and visualized as C++ objects. In this framework, Cling was developed with the aim to facilitate the processing of scientific data in the field of high-energy physics . Cling is a core component of ROOT: it provides essential functionality for the analysis of vast amounts of very complex data produced by the experimental high-energy physics community by enabling (1) interactive exploration in C++, (2) dynamic interoperability (see cppyy, an automatic, runtime Python/C++ binder), and (3) rapid prototyping capabilities.