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Postings from July 2013
On 25 July 2013 22:49, David E. Wheeler <david@justatheory.com> wrote:
> On Jul 24, 2013, at 12:49 AM, chromatic <chromatic@wgz.org> wrote:
>
>> I can't find the relevant branch at the moment, but I'm not sure there is much
>> left salvaging at this point.
>
> Bummer, might have been useful.
>
> I was thinking about what might be the simplest thing to try, and came up with this:
>
> * Create a dead simple .pm exception class like you describe (Maybe you have that lying around somewhere?)
Of course, "dead simple" and "dead simple and also useful" may be 2
different things.
Take this code, which *seems* simple enough that it might work:
------
#!/usr/bin/env perl
use strict;
use warnings;
use utf8;
{
package ExceptionClass;
use overload q{""} => sub {
return $_[0]->{message};
};
sub new {
my ( $self, $message ) = @_;
return bless { message => $message }, $self;
}
}
sub foo {
die ExceptionClass->new('bad') if $ARGV[0] eq 'class';
die 'bad' if $ARGV[0] eq 'native';
}
foo();
---
Doesn't take long before you notice how the string form is superior to
the class form:
$ perl /tmp/e.pl native
# bad at /tmp/e.pl line 21.
$ perl /tmp/e.pl class
# bad
And it breaks your standard "get more backtrace" tools:
$ perl -MCarp::Always /tmp/e.pl native
# bad at /tmp/e.pl line 21.
# main::foo() called at /tmp/e.pl line 24
$ perl -MCarp::Always /tmp/e.pl class
# bad
$perl -MDevel::SimpleTrace /tmp/e.pl native
#bad
# at main::foo(/tmp/e.pl:21)
# at main::(/tmp/e.pl:24)
$perl -MDevel::SimpleTrace /tmp/e.pl class
#bad
You have to start doing crazy (and expensive in pureperl) things just
to have a useable exception class if you try using objects.
--
Kent
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