Re-using your code with Perl modules

Re-use of code, when not copying-and-pasting, is a good thing.  I consider myself beyond a novice Perl programmer.  But since it was never a primary tool at work, I never learned how to develop re-usable Perl modules properly.  Following is a bare-bones implementation of a Perl module.  Note that a module containing a Perl class implementation would not have to use Exporter (nor should it!)

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

package MyPkg;

require Exporter;

our @ISA = qw(Exporter);
our @EXPORT_OK = qw(myfunc);


sub myfunc{ 
 print "bar";
}


1;

In this case, the file containing this code should be named MyPkg.pm, to match the name of the package.  A bare-bones caller of this code could be as simple as:

 

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

use MyPkg qw{myfunc};

myfunc();

Some additional notes:

• In the module, require Exporter; is not always necessary (not yet clear the situation for its necessity)
• If your package is something like MyGroup::MySubGroup, two things to observe:  (1) the name of your .pm file should be MySubGroup.pm and (2) the file should be placed in a subdirectory relative to @INC paths named MyGroup.  For example, if you want to locate your re-usable module togehter with your Perl script, you would put it in a subdirectory of the directory with the Perl script named MyGroup