use PPI;

my $ds = PPI::Document->new('sample_config.pl');

for my $sub ( @{ $ds->find('PPI::Statement::Expression') || [] } ) {

    my $Tokenizer = PPI::Tokenizer->new( \$sub );
    while ( my $Token = $Tokenizer->get_token ) {
         print "Found token '$Token'\n" if ( $Token =~ /\w+/ );
    }
    print "---------------------------------------------\n"
}