c-replUpdate (March 2013): C-REPL was a neat hack, but a more principled implementation of the same goal exists in Cling. Many programming languages come with a REPL (read-eval-print loop), which allows you to type in code line by line and see what it does. This is quite useful for prototyping, experimentation, and debugging code. Other programming languages, and especially C, use a "compile-run" model,
