package MyConstants;

use strict;
use warnings;

use Exporter qw( import );
use constant qw( );

my %constants = (
    FOO => 1,
    BAR => 2,
);

our @EXPORT      = keys(%constants);
our %EXPORT_TAGS = ( all => [ keys(%constants) ] );

constant->import(\%constants);

1;

##</code><code>##

package MyConstants;

use strict;
use warnings;

use Exporter qw( import );

my %constants;
BEGIN {
    %constants = (
        FOO => 1,
        BAR => 2,
    );
}

use constant \%constants;

our @EXPORT      = keys(%constants);
our %EXPORT_TAGS = ( all => [ keys(%constants) ] );

1;