Re: Subroutines: Returning a hash vs. hash reference

[demerphq]

My question to you wise and wonderful monks is whether I should return a hash or a hash reference.

Why lock your users into only one option? Thats not the perl way to do things.

If their code makes more sense with a ref then give them one, if it makes more sense to get a list of key=>value pairs then give it to them.

I avoid the term "to get a hash" as there is no way to return a hash from a subroutine. Instead the hash must be listified into key=>value pairs and then returned that way. Its up to the user to shove that list into an actual hash (or not).

And since this approach involves returning a list then good old perlfunc:wantarray comes to the rescue:

sub get_params {
  my $self = shift;
  my %input;
  $input{$_} = $self->{$cgi_handle}->param($_)
      foreach $self->{$cgi_handle}->param());

  # we return a hashref if the user calls us in scalar context 
  # or a list of key=>values pairs if they call us in list context.
  return wantarray ? %input : \%input;
}

Incidentally this is a standard idiom that can come in very useful. Consider the behaviour of localtime(). You could even insert the following before the return statement

  die "get_params in void context:".Dumper(\%input) unless defined wan
+tarray;

to provide a debugging behaviour for when the sub is called in void context.

HTH

--- demerphq
my friends call me, usually because I'm late....