I've been delving into referencing recently (inspired by HTML::Template), and would very much like some advice.

From Sam Tregars' excellent perldoc HTML::Template documentation describing how to create a <TMPL_LOOP> referenced list: 

  my @words = qw(I Am Cool);
  my @numbers = qw(1 2 3);
  my @loop_data = ();  # initialize an array to hold your loop
  while (@words and @numbers) {
    my %row_data;  # get a fresh hash for the row data
    # fill in this row
    $row_data{WORD} = shift @words;
    $row_data{NUMBER} = shift @numbers;
    # the crucial step - push a reference to this row into the loop!
    push(@loop_data, \%row_data);
  }
  # finally, assign the loop data to the loop param, again with a ref
  $template->param(THIS_LOOP => \@loop_data);

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All well and good, but is there a better or shorter, way to do it? Now, if you're extracting the data from a MySQL table everything can be simplified (via fetchrow_hashref) and by creating a sub (not necessary but useful if extracting data for several loops). 

  sub getLoopData {
    my $table = shift;
    my $order = shift;
    my @fields = @_;
    my $sql = "SELECT " . join (', ', @fields) . " from $table ORDER B
+Y $order";
    my $sth = $dbh->prepare_cached($sql);
    $sth->execute();
    my @rows;
    while (my $row = $sth->fetchrow_hashref) {
      push (@rows, $row);
    }
      return \@rows;
  }

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Which can be called by something like: 

  my $template->param(foo_loop => &getLoopData('foo', 'bar', 'baz', 'm
+oo'));

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Nice. MySQL's fetchrow_hashref function takes care of the referencing for you. I was wondering if theres a nice Perl (golfish) way of doing the same. Sams sample used two arrays, but, what if there was only one, heres a working example: 

  my @years = ();
  my @years_loop = ();
  my $curr_year = (localtime)[5];
  $curr_year += 1900;
  for ($curr_year - 100 .. $curr_year - 5) {
    push (@years, $_);
  }
  while (@years) {
    my %year_data;
    $year_data{year} = shift @years;
    push (@years_loop, \%year_data);
  }
  $template->param(years_loop => \@years_loop);

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Are all the steps within the while loop to get a referenced @years_loop array really necessary? ... well, they are necceasry in this instance otherwise it wouldn't work, but, as asked before, can anyone suggest a better, shorter (or even 'different', in the spirit of learning) way to do it?

This question is asked in the hope that I will get to understand Perl a little better. As can probably be extrapolated from this node I don't really know what I'm talking about so if anyone could throw me some pointers I'd be very grateful. (/me cowers in corner awaiting a thrashing ;)

In reply to A quesion about referencing lists by barrd

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