[ooperl] calling reference to a annonymous sub

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

Dear monks,
I am doing oo perl. I have a reference to a annonymous subroutine in a package "DbManager", and i want to call it in another package "addbook"(The reference is to be passed to HTML::pager). When i execute it, throws error. Can u help me. FYI rowCount works fine.

DbManager package:

my $get_db_data = sub
{
    my ($offset,$per_page)=@_;
    my (@return_array, @data); 
    connectDb() if(!$dbHandle);
    my $stmtHandle = $dbHandle->prepare("select id,name,address,email,
+phone from ADDRESSBOOK limit $offset, $per_page");
    $stmtHandle->execute();
    while(@data = $stmtHandle->fetchrow_array())
    {
        push(@return_array, [@data]);
    }
    $stmtHandle->finish();
    $dbHandle->disconnect();
    return \@return_array;
};
[download]

addbook package:

my $pager = HTML::Pager->new(query=>$query,
                  get_data_callback=>DbManager::get_db_data,
                                rows=>DbManager->rowCount,
                                 page_size=>5,
                                cell_space_color=>'#000000',
                            cell_bacground_color=>'#ffffff',
                                 debug=>1
                                 );
[download]

Thanks in advance..... arunvelusamy

Comment on [ooperl] calling reference to a annonymous sub Select or Download Code

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Re: [ooperl] calling reference to a annonymous sub by Fang (Pilgrim) on Nov 07, 2005 at 08:40 UTC
From what I understand about packages, namespaces and scope, you're missing two things: `$get_data_sub` should be declared with `our`, as in: `% perl -wle'package foo; our $bar = "10"; package main; print $foo::ba +r' 10` [download] Trying the same with `my` will result in a warning when you try to print an uninitialized variable. in your addbook package, add the correct sigil to the variable, i.e. `$DbManager::get_db_data` Hope this helps.	[reply] [d/l]
Re^2: [ooperl] calling reference to a annonymous sub by tphyahoo (Vicar) on Nov 07, 2005 at 09:45 UTC
Yes, and elaborating that so it works with an anonymous sub: `#!/usr/bin/perl #anonysub.pl #use strict; #use warnings; package foo; our $bar = "10\n"; our $anonysub = sub { print "10\n"}; package main; print $foo::bar; &$foo::anonysub(); #before BUU's comment $foo::anonysub->(); #after BUU's comment` [download] outputs: `10 10` [download] (The syntax of the final line took me a bit of trial and error to get it right!) UPDATE: added another way to do it as BUU suggests below, which, I agree, is cleaner.	[reply] [d/l] [select]
Re^3: [ooperl] calling reference to a annonymous sub by BUU (Prior) on Nov 07, 2005 at 10:29 UTC
Just a note, generally it's easier and cleaner to use the `->()` syntax to call subroutine references, as in your example: `$foo::sub->()`.	[reply] [d/l] [select]