On Wednesday, May 23, 2018 04:07:25 Ali Çehreli via Digitalmars-d-learn wrote: > On 05/23/2018 12:47 AM, Robert M. Münch wrote: > > On 2018-05-22 18:34:34 +0000, Ali ‡ehreli said: > >> An idiom known in C++ circles is a Lippincott function: > >> > >> > >> https://cppsecrets.blogspot.ca/2013/12/using-lippincott-function-for.ht > >> ml > >> > >> Just wanted to mention that it can be a part of a clean solution. > > > > Thanks, and I assume that D has the same property WRT exception > > re-throwing as C++, right? > > I think you have to catch and rethrow explicitly: > > import std.stdio; > > void main() { > try { > try { > throw new Exception("Yo"); > } catch (Exception e) { > writeln("Rethrowing"); > throw e; > } > } catch (Exception e) { > writeln(e.msg); > } > } > > Rethrowing > Yo > > Keeping in mind that it's possible to catch Throwable as well but it's > considered less sanitary because it would catch Errors as well, which is > supposed to mean "unrecoverable error". There are long discussions about > whether one should do that or not...
The short answer to that would be that you should never do it. The long answer gets considerably more complicated, and while it _can_ make sense under certain circumstances when you're very careful, it's a minefield of potential problems such that no one who who isn't a very advanced D user who really knows what they're doing should even consider it. Increasingly, I tend to think that D should not have had Errors or any Throwables other than exceptions and should have just printed something useful and exited in a way that created a core dump in any case that's supposed to be non-recoverable. :| Either way, I think that we should be clear that doing anything involving catching anything that isn't an Exception or derived from Exception is fraught with peril and only for advanced users. - Jonathan M Davis
