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How exception-free are they, really? I find in practice that "exception-free" OCaml code relies largely on eyeballing + trusting underlying libraries, which isn

• avsm 12y ago
  The thing to remember with exceptions is that they're for exceptional situations. We check explicitly in the return value for "common" errors such as a read failure, and higher level control flow catches exceptions that bubble up and log them and/or kill that particular thread. This works pretty well in practise, and is quite similar to Erlang's monitor model. It's verbose and undesirable to handle _all_ exceptional cases in a distributed system explicitly via checked exceptions, and using monitors to catch exceptions that we're not expecting and do a process kill/log/restart is a good model in my mind. OCaml gives the language flexibility to migrate to this as well, which is nice (since, as you note, we'll never get all the third-party code we depend on to be exception-free, and nor do I think that is a desirable goal). Core and Async from Jane Street also exhibit this split: Core tends to use On_error to explicitly handle errors, and Async (being used for distributed programming) instead adopts a "raise-exception-and-catch-it-in-a-monitor" model. Theres more on that in the Async chapter in RWO: https://realworldocaml.org/v1/en/html/concurrent-programming-with-async.html https://realworldocaml.org/v1/en/html/concurrent-programming...
  • mercurial 12y ago
    This sounds reasonable. Thank you for the overview.