On 09/05/2011 09:03 PM, Carl Mäsak wrote: > 1parrota (>): >> 1. Should there be a way to make "die" behave like the Perl 5 version, >> reporting the place of death unless the message is terminated by \n ? >> The \n no longer suppresses the location indormation. I can't find a >> definition either way in the Synopses. > > Yes, there should. > > The problem is one of the perfect being the enemy of the good. People > pretty much agree that the mechanism shouldn't be governed by "\n" at > the end of the error string, but no-one has suggested anything > significantly more attractive either. So here we are, currently > without a way to get "die" (and "warn") without location information.
FWIW the current factoring allows the catcher of the exception to control whether a backtrace is printed. A solution is thus to catch exceptions on the outermost level of your program, and print the exception (but not the backtrace) there. A cheap (but probably wrong) approach would simply be a named argument to &die, like die 'OH NOEZ', :suppress-backtrace But as Larry usually points out, such a modified behavior is often a sign of design smell. And I guess that's what happens here: we conflate two concepts here: Error messages that usually stem from errors that the programmer made, and error messages for things that the user did wrong (and which I guess is the reason one wants to surpress backtraces -- are there others?) So I guess the exception object could contain a hint whether the error is a user error or a programming error. All those errors that are thrown by the Perl 6 compiler count as programming error, but we can still provide a X::UserError class, which disables printing of backtraces by default. The question is if we provide a separate sub for such cases (error() or report-error() or so), or if we rely on something like UserError.new(message => 'You did something wrong here').throw or something similar. Cheers, Moritz
