Have you seen Common Lisp’s condition system? It’s a step above exceptions, because one can signal a condition in low-level code, handle it in high-level code and then resume back at the lower level, or anywhere in between which has established a restart.
https://gigamonkeys.com/book/beyond-exception-handling-condi... is a nice introduction; https://news.ycombinator.com/item?id=24867548 points to a great book about it. I believe that Smalltalk ended up using a similar system, too.
It would need to be the case that code that doesn’t want to handle errors (like Max’s simple website) doesn’t have any error handling code, but it’s easy to add, and common patterns (e.g. “retry this inner operation N times, maybe with back off and jitter, and then fail this outer operation, either exiting the program or leaving unaffected parts running”) are easy to express
Lisp’s condition system can handle that! Here’s a dumb function which signals a continuable error when i ≤ 3:
(defun foo ()
(loop for i from 0
do (if (> i 3)
(return (format nil "good i: ~d" i))
(cerror "Keep going." "~d is too low" i))))
If one wishes to retry up to six times, one can bind a handler which invokes the CONTINUE restart:
(let ((j 0))
(handler-bind ((error #'(lambda (c)
(declare (ignore c))
;; only retry six times
(unless (> (incf j) 6)
(invoke-restart 'continue)))))
(foo)))