The C++ interactive interpreter cling is based on LLVM and its C++ frontend clang. It will replaces ROOT's current C++ interpreter CINT. Its main advantages:

• Production-grade parser.
• Just-in-time compiler (JIT), allowing e.g. calls into libraries without wrappers.
• Modular C++ API from the ground up.
• Separate parser and execution engine.
• C++ 11 support through clang.

We have announced cling to the public in 2011. cling is in a very usable state; bugs should be reported to the ROOT project here. We are currently working on the integration of cling into ROOT, i.e. replacing CINT. This work is expected to be released as ROOT 6 end of 2012.

We offer binary snapshots for download. And there are build instructions, both for a stand-alone version of cling and for cling as part of ROOT.

We even have doxygen documentation of cling's code. Presentations covering cling:

• Google Tech Talk (slides, video)
• more clang-centric presentations