for $item @list {

  next if definite failure condition
    
  action if most likely condition
  action if next most likely condition
  etc.

  default action
}

##</code><code>##

for (readdir DIR) {

  next if $_ eq '.' || $_ eq '..';

  push (@files,$_) && next if -f $base/$_;
  push (@dirs,$_) && next if -d $base/$_;

  # default to no operation
}