#!/usr/bin/perl -w

use strict;

my $seen = 0;

while (<DATA>) {
  chop;
  my ($id, $maker, $make) = split(",", $_);
  if ($id != $seen) {
    print "$id. $maker\n";
    print "   - $make\n";
    $seen = $id;
  } else {
    print "   - $make\n";
  }
}

__DATA__
1,gm,saturn
1,gm,chevy
1,gm,caddy
2,ford,taurus
2,ford,escort
3,vw,bug
3,vw,jetta
3,vw,phaeton

##</code><code>##

my @carmakers = (
  \%thismaker,
  \%thismaker,
  \%thismaker
);

##</code><code>##

my %thismaker = ('thismaker' => 'gm', 'makes' => \@makes);

##</code><code>##

my @makes = (\%thismake, \%thismake, \%thismake);

##</code><code>##

my %thismake = ('thismake' => 'saturn');
my %thismake = ('thismake' => 'chevy');
my %thismake = ('thismake' => 'caddy');

##</code><code>##

<tmpl_loop carmakers>
	<tmpl_var thismaker>
	<tmpl_loop makes>
		<tmpl_var thismake>
	</tmpl_loop>
</tmpl_loop>

##</code><code>##

my $seen = 0;

my @carmakers;
while (<DATA>) {
  chop;
  my ($id, $maker, $make) = split(",", $_);
  if ($id != $seen) {
    my %maker;
    $maker{'thismaker'} = $maker;
      my @makes;
      my %make = ('thismake' => $make);
      push(@makes, \%make);
    $maker{'makes'} = \@makes;
    push(@carmakers, \%maker);  # problem1
    $seen = $id;
  } else {   
      my %make = ('thismake' => $make);
      push(@makes, \%make);  # problem2
    $maker{'makes'} = \@makes;
  }
}

##</code><code>##

while (looping over something) {
  if (cond1) {
    create @foo if a certain condition is met
    do a bunch of things
  } else {
    do something to foo already declared
    do a bunch of other things
  }
}