lib/PublicInbox/HlMod.pm | 15 ++++++++++-----
 t/hl_mod.t               |  2 ++

diff --git a/lib/PublicInbox/HlMod.pm b/lib/PublicInbox/HlMod.pm
index decfd714d7ba5e0551b125de94cf16d056642ca6..284e4b1896d46db23fe73613849604448f9c49ec 100644
--- a/lib/PublicInbox/HlMod.pm
+++ b/lib/PublicInbox/HlMod.pm
@@ -83,19 +83,24 @@
 sub do_hl {
 	my ($self, $str, $path) = @_;
 	my $lang = _path2lang($self, $path) if defined $path;
+	do_hl_lang($self, $str, $lang);
+}
+
+sub do_hl_lang {
+	my ($self, $str, $lang) = @_;
+
 	my $dir = $self->{-dir};
 	my $langpath;
+
 	if (defined $lang) {
 		$langpath = $dir->getLangPath("$lang.lang") or return;
-		$langpath = undef unless -f $langpath;
+		$lang = undef unless -f $langpath
 	}
-	unless (defined $langpath) {
+	unless (defined $lang) {
 		$lang = _shebang2lang($self, $str) or return;
 		$langpath = $dir->getLangPath("$lang.lang") or return;
-		$langpath = undef unless -f $langpath;
+		return unless -f $langpath
 	}
-	return unless defined $langpath;
-
 	my $gen = $self->{$langpath} ||= do {
 		my $g = highlight::CodeGenerator::getInstance($highlight::HTML);
 		$g->setFragmentCode(1); # generate html fragment
diff --git a/t/hl_mod.t b/t/hl_mod.t
index c402f1f784f40b3963b53407d706e9bf4d7d93df..238f8ec55b5c23a18ae7a82e9c008fe22ec7f06a 100644
--- a/t/hl_mod.t
+++ b/t/hl_mod.t
@@ -22,6 +22,8 @@ 	is(ref($ref), 'SCALAR', 'got a scalar reference back');
 	ok(utf8::valid($$ref), 'resulting string is utf8::valid');
 	like($$ref, qr/I can see you!/, 'we can see ourselves in output');
 	like($$ref, qr/&&/, 'escaped');
+	my $lref = $hls->do_hl_lang(\$str, 'perl');
+	is($$ref, $$lref, 'do_hl_lang matches do_hl');
 
 	use PublicInbox::Spawn qw(which);
 	if (eval { require IPC::Run } && which('w3m')) {