sub make_expression {
    my ($item, $config) = @_;

    return $config->{prefix} . $item . $config->{suffix};
}

my $formatted_item = make_expression( $item, \%config );

##</code><code>##

my $formatter = Formatter->new( config => \%config );

# many lines and modules later ...
my $formatted_item = $formatter->format( $item );