On Wed, Jan 27, 2016 at 11:06 AM, Felipe Gasper <fel...@felipegasper.com> wrote:
> On 27 Jan 2016 11:03 AM, Brandon Allbery wrote: >> >> On Wed, Jan 27, 2016 at 11:00 AM, Felipe Gasper <fel...@felipegasper.com >> <mailto:fel...@felipegasper.com>> wrote: >> >> Unrelated, but, does open() not throw on failures anyway? (Noodling >> with the perl6 REPL just now seems inconclusive.) >> >> There have been issues with failures in sink context not throwing, IIRC? >> So how you were noodling can matter. >> > > felipe@Macintosh-3 00:45:46 / > > perl6 > > open("/dfgsgsdfgd", :r); > Failed to open file /dfgsgsdfgd: no such file or directory > > my $f = open("/dfgsgsdfgd", :r); > Failed to open file /dfgsgsdfgd: no such file or directory > > print $f; > (HANDLED) Failed to open file /dfgsgsdfgd: no such file or directory > in any at > /Users/felipe/.rakudobrew/moar-2015.12/install/share/perl6/runtime/CORE.setting.moarvm > line 1 > in block <unit> at <unknown file> line 1 > Looks to me like both of them threw? and $f is set to the Failure object instead of a filehandle, which has an annotation saying that it was indeed handled (thrown). Perl 6 has two ways to indicate failure: you can throw immediately, or you can return a Failure object which is a "lazy exception". The latter allows a program to introspect the return value to recognize and handle a Failure without actually throwing it (faster and often cleaner than catching it), or if something just tries to use the value without checking then it throws at that point. It remembers the context in which it was created, so the traceback should indicate that it happened in the open call. -- brandon s allbery kf8nh sine nomine associates allber...@gmail.com ballb...@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
