SPUG: Confusing behaivior with exported variables

[Mark Mertel]

Globals are not recommended. You could make them package variables and declare them with 'my' or 'our', and then access them using the package name $Neo::Web::Session, or $Darley::Supers::CurrentUser when from outside the package. Personally, I'd make an object and fetch them using an accessor, i.e.

my $web = new Neo::Web;

$web->session;

package Neo::Web;

sub new {
...
}

sub session {
...
} ---
Mark Mertel
206.441.4663
mark.mertel at yahoo.com
http://www.linkedin.com/in/markmertel
http://www.seattlejobs.com/13147468 




________________________________
From: Peter Darley <pdarley at kinesis-cem.com>
To: Mark Mertel <mark.mertel at yahoo.com>; spug-list at pm.org
Sent: Monday, March 23, 2009 12:10:14 PM
Subject: RE: SPUG: Confusing behaivior with exported variables


Mark and Tye,
 
                I would have sworn that I took out the my declaration in the second module.  I’ll try removing that and see how it works.
                I usually do use strict as a default, but the first module didn’t have it so I removed it in my efforts to figure out what was going on.
 
Thanks,
Peter
 
From:Mark Mertel [mailto:mark.mertel at yahoo.com] 
Sent: Friday, March 20, 2009 2:16 PM
To: Peter Darley; spug-list at pm.org
Subject: Re: SPUG: Confusing behaivior with exported variables
 
probably should 'use strict' as well. the first package doesn't declare the %Session hash, so it becomes global, and the second package scopes the %CurrentUser inside the BEGIN block. 'use strict' should point these things out.
 
---
Mark Mertel
206.441.4663
mark.mertel at yahoo.com
http://www.linkedin.com/in/markmertel
http://www.seattlejobs.com/13147468 
 
 

________________________________

From:Peter Darley <pdarley at kinesis-cem.com>
To: spug-list at pm.org
Sent: Friday, March 20, 2009 12:35:40 PM
Subject: SPUG: Confusing behaivior with exported variables
Folks,
 
                It’s been a long time since I’ve bugged y’all with a stupid question, but I’ve got a new one so I’m hoping someone can help me out.
 
                The problem is with exporting variables, and having them available to both a script that uses the module exporting the variable, and the module it’s self.  I have two modules, one on a machine at work and one on a machine at home.  Both are doing something that looks super similar to me.
 
                At work I have: 
 
package Neo::Web;
 
use ...
 
use CGI qw/:standard/;
use CGI::Cookie;
use Apache::DBI;
use Apache::Session::Postgres;
use Data::Dumper;
 
BEGIN 
{
                use Exporter   ();
                @ISA         = qw(Exporter);
                @EXPORT      = qw(%Session $SessionID 
                                                  &TieSession &UntieSession ... );
                
                ConnectDB(DBName=>'Sessions');
}
 
sub TieSession
{
                tie %Session, 'Apache::Session::Postgres', $SessionID, {Handle=>$Neo::DB::Sessions, Commit=>0};
                $SessionID = $Session{_session_id};
}
 
                The scripts using this package can get at %Session, and this module can get at %Session.  They are the same variable and have the same contents.
 
                At home I have:
 
package Darley::Supers;
 
use ... ;
 
use Data::Dumper;
 
BEGIN 
{
                my (%CurrentUser);
                
        use Exporter   ();
        @ISA         = qw(Exporter);
        @EXPORT      = qw(%CurrentUser
                                  &Power &Challenge &GetUser &GetOrg &GetCity);
}
 
 
sub SetCurrentOrgSetting
{
                my (%Args) = @_;
                # Args: Setting = Setting to store
                #             Value = Value to store
                
                StoreOrgSetting(OrgID=>$CurrentUser{Org}{org_id}, Setting=>$Args{Setting}, Value=>$Args{Value});
                $CurrentUser{Org}{Settings}{$Args{Setting}} = $Args{Value};
                
                return 1;
}
 
                And the script using this module can get at %CurrentUser, but when this package uses it, it’s empty.  I can’t figure out why the exported hash is the same in the first example, but has two different values in the second.
 
Thanks for any help,
Peter


      
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