4 ms·

They really aren't. Exceptions handle exceptional events that potentially lead to a shutdown, while the Result monad only reports.... Results. I mean, not find

• joshuamorton 6y ago
  > I mean, not finding a record in a database is not an error, nor is getting a response to a HTTP request with status code 3xx or a 404 or a 409. But in some languages, exceptions would be used to handle these cases. Admittedly, those languages are usually higher level than C/C++ (but both Java and Python would probably find it common to handle a 3xx or a 404 or a missing row with an exception) At a high level, I think the important thing is that funct() -> Result<T> and func() -> T that may throw/raise an exception are basically equivalent. Result may require slightly more explicitness at (at least) one call site, but ultimately both allow you to return a T, or report some non-T result, in a structured way. The only difference is that exceptions force you to handle the result explicitly (although that may just mean a single call to value! or VALUE_OR_DIE, or whatever the "get the T or segfault/panic" method is). In this way, I really do think checked exceptions are highly analogous to Result types. Implementations may have different performance tradeoffs, but those aren't implicit in the choice of exception vs. result.