CINT is the closest thing I've ever seen to a real C++ REPL. It's actually used quite extensively in the ROOT data analysis environment (REPL, reflection, UI si

CINT is the closest thing I've ever seen to a real C++ REPL. It's actually used quite extensively in the ROOT data analysis environment (REPL, reflection, UI signal/slot mechanism, object persistency, creating dynamically Python bindings, etc.). As a REPL CINT actually works surprisingly well. Unfortunately it seems to have some problems interpreting certain "advanced" C++ stuff, such as templates and especially code that uses STL heavily. Another problem with it is that since you still need to manage memory manually and have direct access to pointers it's very easy to make CINT (or ROOT) session crash... :( Btw, the ROOT developers are also working on a new LLVM based C++ interpreter called Cling: http://root.cern.ch/drupal/category/package-context/cling http://root.cern.ch/drupal/category/package-context/cling