Callbacks do lead to hell. The back traces half the lead you now-where. I have been writing a scrapy crawler and sometimes when an exception happens it takes some grepping around to figure out where the value that is wrong actually was generated.

Has anyone touched the Google Chrome code base? It is quite difficult to start debugging problems because of the sheer volume of callbacks. Add to that the stack-traces are massive because of the use of templates and other C++ language features.

Async coding needs to be an abstraction within the language. I am curious how languages manage the shared memory. What about the risk of dead locks?