GF: Thank you for short intro to perl modules

I am learning to use perl modules with a small example. Please go through below example, I have a couple of questions at the end

test2.pl is a script that uses perl module test.pm

Contents of test.pl

#!/usr/bin/perl
use strict;
use warnings;
use test;

my @gaga = ("paras", "kansas");

my ($x, $y) = test::test(@gaga);

print "$x\n$y\n";

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contents of test.pm

package test;

sub test
{
       my $tag = $_[0];
       $tag =~ s/p/n/;
       my $bag = $_[1];
       $bag =~ s/k/p/;
       
       return $tag, $bag
}
1;

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output

napas
panas

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above script and module work very well. What I don't understand is..

Query-1: What is function of 1 at the end of test.pm ?

To see whether module works without a subroutine, I modified test.pm, by removing subroutine (see code below)

Contents of test2.pl

#!/usr/bin/perl
use strict;
use warnings;
use test;

my @gaga = ("paras", "kansas");

my ($x, $y) = test(@gaga);    

print "$x\n$y\n";

[download]

contents of test.pm

package test;

         my $tag = $_[0];
       $tag =~ s/p/n/;
       my $bag = $_[1];
       $bag =~ s/k/p/;
       
       return $tag, $bag

1;

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Expected result is... 

napas
panas

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But error message reads... 

test.pm did not return a true value at test2.pl line 4.
BEGIN failed--compilation aborted at test2.pl line 4.

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Query-2: Is it must to have a subroutine inside a module ?

In reply to Re^2: How to give input and collect output of a perl script using another perl script by chakreey
in thread How to give input and collect output of a perl script using another perl script by chakreey

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