Phoronix reader Nicola Mori wrote in about Cling as a CERN research project that's interesting and worthy of a shout out.
Cling is an LLVM/Clang-based C++ interpreter with the advantages according to its developers being a command-line prompt and its using JIT compilation of the C++ code. The ultimate desire is to have a contemporary, high-performance alternative C++ interpreter for their ROOT project.
With leveraging the Clang compiler front-end, Cling can already handle all of the C++ code supported by upstream. The Cling project has been going on for a few years and it's making good headway as a C++ interpreter as shown by their own performance study, plus other data available from the project web-site.
For those wanting to learn more about the Cling C++ interpreter, visit CERN.ch.