Re:Why Common Lisp Is Now the Best Programming Language
by brabel on Tuesday October 06, 2026 @06:32AM
(#49976573)
First , that’s absolutely not how you run a CL server in production. If you had a debugger installed in production, which you shouldn’t, it wouldn just pause there and time out the sockets. What you could do is attach your client to the Lisp system with swank and then make your image changes, later to be synchronized with the actual code in the repo.
Second, other languages can also do that, Java for example has facilities to recompile functions and then rewind the stack to run the function again from the beginning of it. Dart also does that even better and people use that extensively in Flutter with hot reloading. I do that in a debugger during tests though, never seen it done in prod.
And it's not editing files on the server, it's actually reaching into the running code and tweaking its values.
That, I think, is the difference here. In many languages, the debugger can pause on the exception and let you inspect the code. But in every other language I've used, once you edit the code to fix the bug, you can't resume from where the debugger paused. You have to recompile the code and resume from the top. In CL, you can resume from exactly the state you were in when the debugger paused, only this time with the correct data in place. (Or even with a code fix having been applied, live, to the code).