no, forget the web server, there is more, I promise. > we compile our code function-by-function with a keystroke and we get instant warnings and errors, when t

no, forget the web server, there is more, I promise. > we compile our code function-by-function with a keystroke and we get instant warnings and errors, when there is an error we get an interactive debugger that pops up and allows us to inspect the stack, go to the buggy line, recompile, come back to the REPL, resume the execution from the point we want, objects are updated when a class definition changes and we can even control that.