-- main::(gcd.pl:18)
die sprintf "Need two integer arguments, got %d", scalar(@ARGV) unless 
    @ARGV == 2;
basename is on.
highlight is off.
Eval result display style is dumper.
No breakpoints.
No actions.
No watch expressions defined.
x1 main::(gcd.pl:9)
    my ($a, $b) = @_;
-- main::(gcd.pl:11)
    ($a, $b) = ($b, $a) if ($a > $b);
Watch expression 1: $a set
$DB::D[0] = 5
Num Type       Enb Expression
1   watchpoint y   $a
Breakpoint 2 set in gcd.pl at line 14
Watchpoint 1: $a changed
old value	5
new value	3
wa main::(gcd.pl:13)
    return undef if $a <= 0;
gcd.pl [9-18]
  9    	    my ($a, $b) = @_;
 10    	    # Make: a <= b
 11    	    ($a, $b) = ($b, $a) if ($a > $b);
 12    	
 13  ->	    return undef if $a <= 0;
 14 B02	    return $a if ($a == 1) or ($b-$a == 0);
 15    	    return gcd($b-$a, $a);
 16    	}
 17    	
 18    	die sprintf "Need two integer arguments, got %d", scalar(@ARGV) unless 
Num Type          Disp Enb Where
2   breakpoint    keep y   at gcd.pl:14
No actions.
Num Type       Enb Expression
1   watchpoint y   $a
	watchpoint already hit 1 time
trepan.pl: That's all, folks...