> And then what about (...) If seems you've missed the whole point of suggesting the use of Either/Result monads. It's entirely irrelevant if you have legacy c

> And then what about (...) If seems you've missed the whole point of suggesting the use of Either/Result monads. It's entirely irrelevant if you have legacy code that does not support returning error codes a certain way. The whole point of Either/Result monads , specially regarding exceptions, is that they provide a clean way to handle errors (and not exceptions) in the normal code path by explicitly making them a part of a function's codomain, and without relying on magic bubbling up. And no, Either/Result monads are only designed to handle expected results, not exceptional behavior. Perhaps your main source of confusion is conflating exceptions with an error condition. In that case, think of Either/Result monads as "I made a HTTP request and the response was a 200 or a 500 status, thus the code path follows accordingly" and exceptions as "I made a HTTP request and I got an OutOfMemoryException".