Transforming user script code for debugging

User script code that is developed to be run in a host application, for example, as a macro can be transformed into debuggable code so that the host application may continue to operate during a debugging stop operation. Traceback methods can be created that call back into the host application to allow the host application to cooperatively operate and update its user-interface. The user script code can be transformed by injecting callbacks to the traceback methods at respective locations in the code where a stopping operation may be installed during debugging. Further, two or more debugging features can be combined into a single user script code transform using an iterator pattern function.