Trying to pass Hash to Module

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

Hello all, I am probably over my head here, but here goes. I'm trying to pass a hash to a module and it's not working. In my main script, I define a 'module_map' which lists all the modules and calls to them.

sub process_modules {
    my ($active_modules_ref) = @_;  # Accept %active_modules as a refe
+rence
    my %module_map = (
        'clouds'    => sub { CloudUpdate::cloud_update() },
        'volcanoes' => sub { VolcanoXML::process_volcano_data() },
        'storms'    => sub { Storm::fetch_and_process_storms() },
        'quakes'    => sub { Earthquake::get_quakedata() },
        'norad'     => sub {
            my $satellite_file = "$xplanet_satellites_dir\\Norad";
            my $output_tle_file = "$xplanet_satellites_dir\\Norad.tle"
+;
            my $marker_file = "$xplanet_satellites_dir\\Norad_marker.t
+xt";
            Norad::process_satellites($satellite_file, $output_tle_fil
+e, $marker_file);
        },
        'fires'     => sub { Fires::run() },
        'labelupdate' => sub {
            print "process_modules - Debug: Calling WriteoutLabel with
+ active_modules_ref:\n" if $DEBUG;
            foreach my $key (keys %$active_modules_ref) {
                print "  $key => $active_modules_ref->{$key}\n" if $DE
+BUG;
            }
            Label::WriteoutLabel($active_modules_ref);  # Pass as a re
+ference
        },
    );

    foreach my $module (keys %Globals::modules) {
        my ($onoff_key) = grep { /onoff$/i } keys %{ $Globals::modules
+{$module} };

        if ($onoff_key && $Globals::modules{$module}{$onoff_key} == 1)
+ {
            print "Processing module: $module\n" if $DEBUG;

            if (exists $module_map{$module}) {
                $module_map{$module}->($active_modules_ref);
            } else {
                warn "No subroutine mapped for module: $module\n" if $
+DEBUG;
            }
        } else {
            print "Module: $module, On/Off: Undefined or Inactive\n" i
+f $DEBUG;
        }
    }
}
[download]

The key module in this 'process_modules' subroutine is the labelupdate call

'labelupdate' => sub {
            print "process_modules - Debug: Calling WriteoutLabel with
+ active_modules_ref:\n" if $DEBUG;
            foreach my $key (keys %$active_modules_ref) {
                print "  $key => $active_modules_ref->{$key}\n" if $DE
+BUG;
            }
            Label::WriteoutLabel($active_modules_ref);  # Pass as a re
+ference
[download]

Given that's the call to use, then my main script invokes process_modules as follow:


# Process modules
process_modules(\%active_modules);
[download]

Where the program goes off to the Label::WriteoutLabel routine and dies because the hash is undefined. I can't figure out how to pass the hash in. I double checked the process_modules call uses '\%...' so I am stumped. Oh, the WriteoutLabel routine reads as follows:

package Label;
use strict;
use warnings;
use Data::Dumper;
use Time::Local;  # Load the Time::Local module

use Globals qw(
    $DEBUG 
    $label_file 
    $labelsettings
);  


sub WriteoutLabel {
    print "Label line 31 - Debug: \$DEBUG is " . ($DEBUG ? "enabled" :
+ "disabled") . "\n";

    my ($active_modules_ref) = @_;

    # Skip label generation if labelsdisplay is disabled
    my $labels_display = $Globals::modules{'labels'}{'labelsonoff'} //
+ 1;  # Default to 1 (enabled)
    return unless $labels_display;

    print "Label line 39 - Debug: Labels display is " . ($labels_displ
+ay ? "enabled" : "disabled") . "\n" if $DEBUG;

    # Debug: Check that active_modules_ref is a hash reference
    unless (ref $active_modules_ref eq 'HASH') {
        print "Label::WriteoutLabel - Received invalid active_modules_
+ref: " . (ref $active_modules_ref || 'undefined') . "\n" if $DEBUG;
        die "Error: active_modules_ref is not a HASH reference.";
    }
...
[download]

I have tried my ($self, $active_modules_ref) = @_; and varieties thereon. Thank you in advance,

Comment on Trying to pass Hash to Module Select or Download Code

Replies are listed 'Best First'.
Re: Trying to pass Hash to Module by GrandFather (Saint) on Jan 29, 2025 at 02:27 UTC
`use strict; use warnings; my %active_modules = ( 'clouds' => sub { CloudUpdate::cloud_update() }, 'volcanoes' => sub { VolcanoXML::process_volcano_data() }, ); process_modules(\%active_modules); sub process_modules { my ($active_modules_ref) = @_; # Accept %active_modules as a refe +rence print join "\n", keys %$active_modules_ref; }` [download] prints the hash keys as I would expect. What is different with your code? Maybe you could simplify your code to a similar test script to demonstrate the problem? Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond	[reply] [d/l]
Re^2: Trying to pass Hash to Module by mcoblentz (Scribe) on Jan 30, 2025 at 23:32 UTC
Thank you all for looking this over. I will attempt to make a much simpler version of this and duplicate the problem.	[reply]
Re: Trying to pass Hash to Module by LanX (Saint) on Jan 29, 2025 at 06:13 UTC
Your code is confusingly complicated, and we don't know which `%Globals` entries you are using. But I think this is the point where you call the `$module = "labelupdate"` routine > `$module_map{$module}->($active_modules_ref)` But `labelupdate` doesn't accept resp. unpack any arguments, `$active_modules_ref` is taken from the surrounding closure. This might not be the reason for your problem tho. But you should really untangle your code to show a clearer logic, if such bugs happen. Cheers Rolf _{(addicted to the Perl Programming Language :) see Wikisyntax for the Monastery}	[reply] [d/l] [select]
Re: Trying to pass Hash to Module by Marshall (Canon) on Jan 29, 2025 at 10:46 UTC
I don't see where you are getting the error. Try to make a simple example that we can all run which prints the error. This is fine: package Label; use strict; use warnings; use Data::Dumper; use Time::Local; # Load the Time::Local module our $DEBUG =1; our $label_file = "somefile"; our $labelsettings ="some settings"; my $active_modules_ref = {clouds => 1 , quakes => 1}; sub WriteoutLabel { print "Label line 31 - Debug: \$DEBUG is " . ($DEBUG ? "enabled" : + "disabled") . "\n"; my ($active_modules_ref) = @_; # Skip label generation if labelsdisplay is disabled my $labels_display = 1; # Default to 1 (enabled) return unless $labels_display; print "Label line 39 - Debug: Labels display is " . ($labels_displ +ay ? "enabled" : "disabled") . "\n" if $DEBUG; # Debug: Check that active_modules_ref is a hash reference unless (ref $active_modules_ref eq 'HASH') { print "Label::WriteoutLabel - Received invalid active_modules_ +ref: " . (ref $active_modules_ref \|\| 'undefined') . "\n" if $DEBUG; die "Error: active_modules_ref is not a HASH reference."; } } WriteoutLabel($active_modules_ref); __END__ Label line 31 - Debug: $DEBUG is enabled Label line 39 - Debug: Labels display is enabled [download]	[reply] [d/l]