retry code snippet

ccn has asked for the wisdom of the Perl Monks concerning the following question:

I have a snippet that makes several retries of a code. I am not fully satisfied with it. I don't like the name try because it belongs to exceptions slang. And I think the snippet can be more elegant.
Any suggestions appreciated

sub try(&@) {
    my $job = shift;
    my $retries = shift || 1;
    my $timeout = shift || 1;

    my $res;
    while (!$res) {
        $res = &$job;
    }
    continue {
        return unless --$retries;
        sleep $timeout;
    }
    return $res;
}

try { get_web_page() } 10, 10
  or die "Can't get page";
[download]

Comment on retry code snippet Select or Download Code

Replies are listed 'Best First'.
Re: retry code snippet by ihb (Deacon) on Oct 18, 2004 at 15:47 UTC
I suggest Attempt which already is there for you - ready to use. `;-)` `ihb` Read argumentation in its context!	[reply] [d/l] [select]
Re: retry code snippet by tmoertel (Chaplain) on Oct 18, 2004 at 16:12 UTC
As long as your job fails and there are retries left, sleep and then try the job again. We can write this as follows: `sub retry { my $job = shift; my $retries = shift \|\| 1; my $delay = shift \|\| 1; my $res; sleep $delay while !($res = &$job) && --$retries; return $res; }` [download] (I renamed `$timeout` to `$delay`, which more accurately describes what it is. A timeout is usually the maximum time that you're willing to let an operation proceed before giving up and canceling it.) Just to be safe, let's test our code with Test::More: use Test::More tests => 5; is( retry(sub{0}), 0 , "always-failing job fails 1 retry" ); is( retry(sub{0}, 2), 0 , "always-failing job fails 2 retries" ); is( retry(sub{1}, 0), 1 , "always-succeeding job succeeds regardless of retries" ); is( retry(mk_counter(), 1), 0 , "succeed-on-second job fails if given only 1 retry" ); is( retry(mk_counter(), 2), 1 , "succeed-on-second job succeeds if given 2 retries" ); # helper that makes fns that return 0 on 1st call, 1 on 2nd, ... sub mk_counter { my $i = 0; sub { $i++ } } [download] And the test results: `1..5 ok 1 - always-failing job fails 1 retry ok 2 - always-failing job fails 2 retries ok 3 - always-succeeding job succeeds regardless of retries ok 4 - succeed-on-second job fails if given only 1 retry ok 5 - succeed-on-second job succeeds if given 2 retries` [download] Cheers, Tom Tom Moertel : Blog / Talks / CPAN / LectroTest / PXSL / Coffee / Movie Rating Decoder	[reply] [d/l] [select]
Re: retry code snippet by perrin (Chancellor) on Oct 18, 2004 at 16:14 UTC
I received many good answers to this here.	[reply]
Re: retry code snippet by Anonymous Monk on Oct 18, 2004 at 15:46 UTC
use Sub::Attempts;	[reply]