CODEWITHSUNDEEP
perlconstants
qodeninja
qodeninja

Reputation: 11266

How do you print exported module constants in Perl?

I want to define some constants in one package and then use them in another package, but I don't seem to be doing this right! At first shot I was getting

Bareword "FAVORITE_COLOR" not allowed while "strict subs" in use at ...

I guess it was because I wasn't using the base path for my package in the lib() function,

Module My/Colors.pm

package My::Colors;

BEGIN {
  use Exporter;
  our($VERSION, @ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS);
  $VERSION     = 1.00;
  @ISA         = qw(Exporter);
  @EXPORT      = qw(  );
  @EXPORT_OK   = qw( FAVORITE_COLOR DISLIKED_COLOR );  
  %EXPORT_TAGS = ( 'all' => [ @EXPORT, @EXPORT_OK ], 'const' => [ 'FAVORITE_COLOR', 'DISLIKED_COLOR'] ); 

}
our @EXPORT_OK;

use lib qw( /home/dev );

use Carp;


use constant {     
  DISLIKED_COLOR => "green",
  FAVORITE_COLOR => "red"
};

sub new {
 my($class, %args) = @_;
 my $self = bless({}, $class);
 my $target = exists $args{target} ? $args{target} : "new";
 $self->{target} = $target;
 return $self;
}


1;

Module that includes exported constants color_driver.plx

#!/usr/bin/perl -w
use warnings;
use strict;
use diagnostics;

use lib qw( /home/dev/My );
use Colors;
use Colors qw(:const);


sub main{
  my $color = new Colors;
  print "Color is",FAVORITE_COLOR;

}

main();

any idea what I'm doing wrong?

When I remove strict the constant doesnt translate to its value =/

Updated Unfortunately now perl is complaining that it can't find new sub

Can't locate object method "new" via package "Colors" (perhaps you forgot to load "Colors"?) at color_driver.plx line 15 (#1)

Upvotes: 1

Views: 747

Answers (1)

ikegami
ikegami

Reputation: 385496

In the module:

package My::Colors;

In the script:

use lib qw( /home/dev/My );
use Colors qw(:const);

my $color = new Colors;

Either change those lines of the module to

package Colors;

or change those lines of the script to

use lib qw( /home/dev );
use My::Colors qw(:const);

my $color = new My::Colors;

use Colors qw( :const );

is almost identical to

BEGIN {
    require Colors;
    Colors->import(qw( :const ));
}

You are telling Perl to look in the Colors package/namespace for import (and new), but the module populates the package/namespace My::Colors.

Upvotes: 3

Related Questions