R – way to encapsulate the common Perl functions into their own scripts


I am maintaining several Perl scripts that all have similar code blocks for different functions. Each time a code block is updated, I have to go through each script and manually make the change.

Is there a way to encapsulate the common functions into their own scripts and call them?

Best Solution

There are other ways, but they all have severe issues. Modules are the way to go, and they don't have to be very complicated. Here is a basic template:

package Mod;

use strict;
use warnings;

use Exporter 'import';

#list of functions/package variables to automatically export
our @EXPORT = qw(

#list of functions/package variables to export on request
our @EXPORT_OK = qw(

sub always_exported { print "Hi\n" }

sub exported_on_request { print "Hello\n" }

sub also_exported_on_request { print "hello world\n" }

1; #this 1; is required, see perldoc perlmod for details

Create a directory like /home/user/perllib. Put that code in a file named Mod.pm in that directory. You can use the module like this:


use strict;
use warnings;

#this line tells Perl where your custom modules are
use lib '/home/user/perllib';

use Mod qw/exported_on_request/;


Of course, you can name the file anything you want. It is good form to name the package the same as file. If you want to have :: in the name of the package (like File::Find) you will need to create subdirectories in /home/user/perllib. Each :: is equivalent to a /, so My::Neat::Module would go in the file /home/user/perllib/My/Neat/Module.pm. You can read more about modules in perldoc perlmod and more about Exporter in perldoc Exporter

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