Walter Bright <newshou...@digitalmars.com> wrote: > On 1/11/2015 5:06 AM, Dicebot wrote: >> What is your opinion of approach advertised by various functional languages >> and >> now also Rust? Where you return error code packed with actual data and can't >> access data without visiting error code too, compiler simply won't allow it. > > It's a great question. I have a lot of experience with error codes, and > with exceptions. I have zero with the packed scheme, though that doesn't > stop me from having an opinion :-) > > Perhaps I misunderstand, but given A calls B calls C, > > A => B => C > > and C detects an error, and A knows what to do with the error. B then > becomes burdened with checking for the error, invoking some sort of > cleanup code, and then propagating it. > > Wouldn't this be uglifying B's source code? > > With exceptions, C throws, A catches, and B's cleanup happens automatically. > > This matters very much for pipeline style programming (i.e. ranges and > algorithms).
- Error codes are automatically ignored - Exceptions are automatically propagated IMO both are not ideal and lead to sloppy programming. Ignoring errors is of course worse than aborting where you could have handled the error. Rust-style "packed" errors are nice because you are forced to think about the correct handling.
