Re: Logging Singleton

[7stud]

in reply to Logging Singleton

Please let me know if there is a better way or a perferred method.

1. Rename new() to get_logger()?
2. Use a closure?

use strict;
use warnings;
use 5.012;

package Log;

{

    my $logger;

    sub get_logger {
        if (not $logger) {
            my ($class, $path) = @_;

            say "Creating logger...";

            $logger = {};
            bless $logger, "Log";
            $logger->create_logfile($path);

        }
        else {
            say "Logger already exists..."
        }

        return $logger;
    }
}

sub create_logfile {
}

sub do_stuff {
    #$logger = 'hello';
}

use strict;
use warnings;
use 5.012;

use Log;

my $log = Log->get_logger();   #Creating logger...
$log = Log->get_logger();       #Logger already exists...
$log = Log->get_logger();       #Logger already exists...

#$log->do_stuff;

With a closure, you can't (mistakenly) change the $logger singleton in another subroutine:

Global symbol "$logger" requires explicit package name at Log.pm line 
+32.
Compilation failed in require at 2.pl line 5.

The my variable $logger ceases to exist after the end of the block, and thereafter only the sub get_logger() can see the $logger variable.

[Anonymous Monk]

Thank you. Haven't implemented a closure before but I'll read up on them. Thanks!