perl -lwe'$oldtime = $^T;

          print( -(($oldtime+0) - ($oldtime = time)) )
                                            while sleep 1'

##</code><code>##

my $tm = time;  print $tm - $oldtm;  $oldtm = $tm;

##</code><code>##

( -(($oldtime || $^T) - ($oldtime = time)) )

##</code><code>##

perl -e'$\=$,=$";$b=1;
        print $b, $a += $b += $a while $a <1000;
        print"\n"'

##</code><code>##

-( (x + 0) - (x = y) )

##</code><code>##

(x = y) - (x)

##</code><code>##

x - x

##</code><code>##

0

##</code><code>##

print 0;