Is it possible to call a subroutine in the main package from a Perl module? I want to implement a dispatch table in the module, but have been trying for two days to figure out how to call the subroutine by reference (and I even tried calling it with a name in a variable).

package ProcessData;
use strict;
no strict "refs";
use Carp qw(croak);

sub new {
    my ($pkg) = $_[0];
    bless {
        _dispatch_table => {},
    }, $pkg;
}

sub add_subroutine {
    if($_[1] && $_[2]) {
        if(ref($_[2]) eq "CODE") {
            ${$_[0]->{_dispatch_table}}{$_[1]} = $_[2];
        } else {
            croak "The reference passed to add_subroutine() is not a C
+ODE reference. ";
        }
    } else {
        croak "Insufficient arguments passed to add_subroutine(). ";
    }
}

sub process_data {
    if($_[1] && $_[2]) {
        #I've tried:
        ${$_[0]->{_dispatch_table}}{$_[1]}->($_[2]);
        
        #and tried
        ${${$_[0]->{_dispatch_table}}{$_[1]}}->($_[2]);

        #and some pretty odd other comibnations
        
        ... do stuff with the data ...
    } else {
        croak "Insufficient arguments passed to process_data(). ";
    }
}

sub process_locations {
    $_[0]->process_data("locations");
}


test.pl
use strict;
use ProcessData;


my $pd = ProcessData->new();

#Add references to the dispatch table.
$pd->add_subroutine("dates", \&get_dates);
$pd->add_subroutine("locations" \&get_locations);
$pd->add_subroutine("contact_list", \&contact_list);

$pd->process_locations;

[download]

This is a simplified code example, I'm trying to lean how to do this with a dispatch table. It's not something real ... yet... which is good ... because I haven't been able to Goolge an answer yet.

In reply to Is it possible to call a package::main subroutine from a module? by TorontoJim

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.