###
### make-dfs-search-simple
###

## Chapter 5 section 3

use Iterator_Utils 'Iterator';

sub make_dfs_search {
  my ($root, $children) = @_;
  my @agenda = $root;
  return Iterator {
    return unless @agenda;
    my $node = pop @agenda;
    push @agenda, $children->($node);
    return $node;
  };
}