# pseudocode

sub dir_reader {
  # ...
  while  (my ($curdir, $name) = next_in_tree()) {
    -e "$curdir/$name" or lob "Couldn't open file $name";
    push @files, $name;
  }
  # ...
  return @files;
}

sub keep_on {
  try { dir_reader(@_) } 
  bounce { /.*(\S+)$/; push @badfiles, $1;}
}

sub give_up {
  try { dir_reader(@_) } 
 catch{ die "Couldn't open file $_"}
}