use strict;
use warnings;
use Data::Dumper;
use Carp;

sub subrange_pre_golf {
  my ($r1,$r2,$ary,$s,$f)=@_;
  ($s,$f)=(0,$#$ary) unless $s && $f;
  ($_<$s && $_<$f or $_>$s && $_>$f) and die "Bad range!"
    for $r1,$r2;
  my ($dx,$idx,@ret)=($r2 <=> $r1);
  $idx=($s < $f) ? -$s+$r1 : ($dx=-$dx,$s-$r1);
  while ( @ret <= abs($r2-$r1) ) {
    push @ret,$ary->[$idx];
    $idx+=$dx;
  }
  return @ret;
}


# Excluding sub {} wrapper its 126 bytes.
#         1         2         3         4         5         6         7
#123456789012345678901234567890123456789012345678901234567890123456789012345678
sub subrange_no_error {
 my($p,$q,$Y,$s,$f)=@_;my($d,$i,@r)=($q<=>$p);$i=($s<$f)?-$s+$p:($d=-$d,$s-$p);
 push(@r,$Y->[$i]),$i+=$d while@r<=abs($q-$p);@r;
}

#180 bytes (counting newline used as mandatory whitespace as one char)
sub subrange_golf_error {
 my($p,$q,$Y,$s,$f)=@_;my($d,$i,@r)=($q<=>$p);$i=($s<$f)?-$s+$p:($d=-$d,$s-$p);
 ($_<$s&&$_<$f||$_>$s&&$_>$f)&&die"Bad range!"for$p,$q;push(@r,$Y->[$i]),$i+=$d
 while@r<=abs($q-$p);@r;
}

# this is now just a wrapper to subrange. Its just for testing and interface
# compatibility
sub arrange {
  my $href=shift;
  my @ret= subrange_golf_error(@{$href->{subrange}},$href->{arr},@{$href->{range}});
    $href->{ret}=\@ret;
  unless (defined wantarray) {
    my $idx=$href->{range}[0];
    my $dx=$href->{range}[1] <=> $href->{range}[0];
    print "Subrange @{$href->{subrange}} of Array [".
          join(", ", map{ my $r="$idx:$_"; $idx+=$dx; $r } @{$href->{arr}})
          ."] is <@ret>\n";
  } else{
    return wantarray ? @ret : \@ret;
  }
}

foreach my $t ([5,8],[8,5],[6,5],[6,7],[5,6],[7,6],[1,2],[8,9]) {
  foreach my $r ([8,5],[5,8]) {
    eval {
      arrange({
        arr => [qw(cero uno dos tres)],
        range => $r,
        subrange =>$t
      });
      1
    } or warn "Test @$t failed on range @$r:\n$@";
  }
}