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Re: Idomatic Handling of Subroutine Error

by btrott (Parson)
on Sep 18, 2001 at 22:58 UTC ( #113177=note: print w/replies, xml ) Need Help??

in reply to Idomatic Handling of Subroutine Error

Other posters have mentioned exceptions; that's a good way to go.

Another option is more similar to the sample code you posted. If you are willing to call your subroutines as object or class methods, you can have your methods return undef on error, and set either an instance variable or a class variable, which the calling code can then access using some other method you set up, like 'errstr'. For example, here is some error-handling code I use:

use vars qw( $ERROR ); sub new { bless {}, shift } sub error { my $msg = $_[1]; $msg .= "\n" unless $msg =~ /\n$/; if (ref($_[0])) { $_[0]->{_errstr} = $msg; } else { $ERROR = $msg; } return; } sub errstr { ref($_[0]) ? $_[0]->{_errstr} : $ERROR }
In your methods you can now do:
return $obj->error("Got an error") unless $foo; ## OR return $class->error("Got an error") unless $foo;
And in the calling code you can do:
$obj->foo or die $obj->errstr; ## OR My::Class->foo or die My::Class->errstr;

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[erix]: we frown :)
[marto]: Does the command line arg --product-version@ help?
[LanX]: xD
[erix]: 'systematic' is going to be hard to define I think
[marto]: Err no @
LanX Much enemy much ore
[Corion]: marto: Naah, my module doesn't care, but the users of my module might expect some things to work in Chrome that only work in later builds (or, as seems to be the case, don't work there either ;) )
[Corion]: But I really wonder - I can tell Chrome to go offline, but requesting pages over the network still succeeds. But if I manually click the "offline" checkbox, that's different :-/

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