use strict;
use warnings;

##</code><code>##

sub parse {
    my ($self,$hashref)=@_;
    open my $fh, '<:raw', $self->{FILE} or die $!;
    while (<$fh>) {
        chomp;
        $hashref->{$_}++ for split;
    }
}

##</code><code>##

#!/usr/bin/perl -l

use strict;
use warnings;

package Foo;

sub new {
    my ($self,$file)=@_;
    bless { FILE => $file }, $self;
}

sub parse {
    my ($self,$hashref)=@_;
    open my $fh, '<:raw', $self->{FILE} or die $!;
    while (<$fh>) {
        chomp;
        $hashref->{$_}++ for split;
    }
}

package main;

my ($file,%hash)=shift;
Foo->new($file)->parse(\%hash);  # right
Foo::parse(%hash);               # wrong
print for keys %hash;

__END__