--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_muc_reserve_nick_pattern/mod_muc_reserve_nick_pattern.lua	Mon Feb 20 13:42:13 2023 -0500
@@ -0,0 +1,15 @@
+local jid = require "util.jid";
+local st = require "util.stanza";
+
+local nick_patterns = module:get_option_array("muc_reserve_nick_patterns", {});
+
+module:hook("muc-occupant-pre-join", function (event)
+	local nick = jid.resource(event.occupant.nick);
+	for k, nick_pattern in pairs(nick_patterns) do
+		if nick:match(nick_pattern) then
+			local reply = st.error_reply(event.stanza, "modify", "conflict", "Unacceptable nickname, please try another");
+			module:send(reply);
+			return true;
+		end
+	end
+end);