#!perl 
use strict;


my @RootArticles = ("ArtA", "ArtB", "ArtC");
my %Children = (
		"ArtA" => "ArtD|ArtE|ArtF",
		"ArtE" => "ArtG|ArtH",
		"ArtC" => "ArtI|ArtJ",
		"ArtI" => "ArtK",
		"ArtK" => "ArtL",
	       );
foreach (@RootArticles) {
    &Printout ("", $_);
    &getarticles("", $_);
}

sub getarticles {
	my $IndentString = shift;
        my $article = shift;
	my @Replies = ();
        foreach (split(/\|/, $Children{$article})) {
	    push (@Replies, $_);
        }
	while (my $reply = pop(@Replies)) {
	    &Printout($IndentString . '`---', $reply);
	    my $NewIndent = (@Replies)?"|   ":"    ";
	    &getarticles( $NewIndent . $IndentString, $reply);
	}
        return 1;
}

sub Printout {
    my ($IndentString, $String) = @_;
    print "$IndentString$String\n";
}