Right, I meant derive. Sorry. I was just trying to understand the best way to deal with errors in Clojure. I thought what you were saying was that we could derive exceptions from RuntimeException and they wouldn't get wrapped. It seems to negate the value of try/catch if every exception (including RuntimeExceptions) are wrapped in RuntimeExceptions that have to be unwrapped to find the true cause. I have noticed in the REPL in emacs I have to usually drill down three or four levels to find the true cause (and file and line no) of an exception.
However, since I'm relatively new here, I did a search in the archive, and turned up this message, which seems to layout a better, more Clojureish way to handle errors using dynamic vars bound to 'recovery' functions. http://groups.google.com/group/clojure/msg/842e8bb058015282 Paul On Fri, Oct 24, 2008 at 8:18 AM, Rich Hickey <[EMAIL PROTECTED]> wrote: > > > > On Oct 24, 7:46 am, "Paul Stadig" <[EMAIL PROTECTED]> wrote: >> So the moral of the story (in terms of idiomatic clojure) is to >> declare RuntimeExceptions instead of Exceptions (if you need to >> declare an exception)? Or is there a better way to handle errors? >> > > You don't declare exceptions in Clojure. If you mean derive from > RuntimeException, that won't help, as at present most wrapping > contexts just catch any Exception (which will catch RuntimeExceptions) > and throw wrapped in a new RuntimeException. I recommend you try to > use an existing Exception type when possible (there are too many > already), and derive from Exception otherwise. > > The real issue is on the handling side. In general, I think unless you > are directly calling something that declares specific exceptions, you > need to catch Exception then see what you've got, including examining > the cause. You should presume that all generic plumbing, i.e. most of > Clojure, might throw Exceptions, sometimes wrapping others. > > Rich > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
