-# Third-party commands can be listed in the sequences, but should be
-# listed here as well. They will not be run if not present.
-my %thirdparty=map { $_ => 1 } qw{
- dh_pycentral
- dh_pysupport
-};
+# sequence addon interface
+sub _insert {
+ my $offset=shift;
+ my $existing=shift;
+ my $new=shift;
+ foreach my $sequence (keys %sequences) {
+ my @list=@{$sequences{$sequence}};
+ next unless grep $existing, @list;
+ my @new;
+ foreach my $command (@list) {
+ if ($command eq $existing) {
+ push @new, $new if $offset < 0;
+ push @new, $command;
+ push @new, $new if $offset > 0;
+ }
+ else {
+ push @new, $command;
+ }
+ }
+ $sequences{$sequence}=\@new;
+ }
+}
+sub insert_before {
+ _insert(-1, @_);
+}
+sub insert_after {
+ _insert(1, @_);
+}
+sub remove_command {
+ my $command=shift;
+ foreach my $sequence (keys %sequences) {
+ $sequences{$sequence}=[grep { $_ ne $command } @{$sequences{$sequence}}];
+ }
+
+}
+sub add_command {
+ my $command=shift;
+ my $sequence=shift;
+ unshift @{$sequences{$sequence}}, $command;
+}
+
+if ($dh{LIST}) {
+ my %addons;
+
+ for my $inc (@INC) {
+ eval q{use File::Spec};
+ my $path = File::Spec->catdir($inc, "Debian/Debhelper/Sequence");
+ if (-d $path) {
+ for my $module_path (glob "$path/*.pm") {
+ my $name = basename($module_path);
+ $name =~ s/\.pm$//;
+ $name =~ s/_/-/g;
+ $addons{$name} = 1;
+ }
+ }
+ }
+
+ for my $name (sort keys %addons) {
+ print "$name\n";
+ }
+
+ exit 0;
+}
+
+foreach my $addon (@{$dh{WITH}}) {
+ my $mod="Debian::Debhelper::Sequence::$addon";
+ $mod=~s/-/_/g;
+ eval "use $mod";
+ if ($@) {
+ error("unable to load addon $addon: $@");
+ }
+}