-- main::(gcd.pl:18)
die sprintf "Need two integer arguments, got %d", scalar(@ARGV) unless 
Eval result display style is dumper.
set auto eval is on.
set max width is 300.
$DB::D[0] =
@{[
  'main',
  'gcd.pl',
  18
]}
-> main::(gcd.pl:8)
{ 
x1 main::(gcd.pl:9)
    my ($a, $b) = @_;
$DB::D[1] =
@{[
  'main',
  'gcd.pl',
  9
]}
$DB::D[2] =
@{[
  'main',
  'gcd.pl',
  21
]}
trepan.pl: That's all, folks...