my $i=0;
for( $i=0; $i<=$n; $i++ ) {
   $list[$i] = &foo(1, 2, 3, 4, 5);
   if( $#list > &max_length )
   {
      last;
   }
   my $result = &bar("$n", @list);
   if( $result > 999.999 )
   {
       print STDERR "System halt";
       exit;
   }
}

##</code><code>##

for( 0 .. $n )
{
   push @list, foo(1 .. 5);
   last if @list >= max_length();
   warn('System halt') and exit if bar($n => @list) > 999.999;
}