NOTE: use Perl; is on undef hiatus. You can read content, but you can't post it. More info will be forthcoming forthcomingly.
All the Perl that's Practical to Extract and Report
an endless discussion thread about what features to include.
-- Jarkko Hietaniemi
Stories, comments, journals, and other submissions on use Perl; are Copyright 1998-2006, their respective owners.
eval {} or do_something (Score:1)
Following the eval block with an "or" seems to be more reliable than using "
if ($@)" to check for an exception in an eval block, because an eval block (or even an eval EXPR) returns undef if there is a syntax error or runtime error or a die statement is executed (according to perldoc -f eval).eval {
my $obj = SomeClass->new();
die "Code Red!\n";
} or print "Exception caught: $@\n";
But even with this technique the $@ is reset by the destructor in your example, so while the exception at least can be caught we lose the information $@ would provide but for the destructor. The output is merely
"Exception caught:"
The documentation for eval says that $@ is guaranteed to be a null string if no exception occurred; I had not appreciated the precise scope of that statement until seeing your example (it doesn't go on to say that, conversely, $@ is guaranteed not to be a null string if an exception occurred).
I believe I heard schwern advocating at YAPC 2008 the use of
... }
eval {
or warn_about_problem();
rather than
... };
eval {
if ($@) { warn_about_problem() }
This might have been the kind of situation he had in mind.
Reply to This