Example: Module Template (Perl Cookbook, 2nd Edition)

12.22. Example: Module Template

Following is the skeleton of a module. If you want to write a module of your own, you can copy this and customize it.

package Some::Module;  # must live in Some/Module.pm

use strict;

require Exporter;

# set the version for version checking
our $VERSION     = 0.01;

our @ISA         = qw(Exporter);
our @EXPORT      = qw(&func1 &func2 &func4);
our %EXPORT_TAGS = ( );     # eg: TAG => [ qw!name1 name2! ],

# your exported package globals go here,
# as well as any optionally exported functions
our @EXPORT_OK   = qw($Var1 %Hashit &func3);

use vars qw($Var1 %Hashit);
# non-exported package globals go here
our(@more, $stuff);

# initialize package globals, first exported ones
$Var1   = "";
%Hashit = ( );

# then the others (which are still accessible as $Some::Module::stuff)
$stuff  = "";
@more   = ( );

# all file-scoped lexicals must be created before
# the functions below that use them.

# file-private lexicals go here
my $priv_var    = "";
my %secret_hash = ( );

# here's a file-private function as a closure,
# callable as &$priv_func.
my $priv_func = sub {
    # stuff goes here.
};

# make all your functions, whether exported or not;
# remember to put something interesting in the {  } stubs
sub func1      { .... }    # no prototype
sub func2( )    { .... }    # proto'd void
sub func3($$)  { .... }    # proto'd to 2 scalars

# this one isn't auto-exported, but could be called!
sub func4(\%)  { .... }    # proto'd to 1 hash ref

END { }       # module cleanup code here (global destructor)

1;