add option to change chat command character

src/ChatCommands.cc

@@ -3183,9 +3183,9 @@ struct SplitCommand {
 asio::awaitable<void> on_chat_command(std::shared_ptr<Client> c, const std::string& text, bool check_permissions) {
   SplitCommand cmd(text);
 
-  // This function is only called by on_06 if it looks like a chat command (starts with $, or @ on 11/2000), so we just
-  // normalize all commands to $ here
-  if (!cmd.name.empty() && cmd.name[0] == '@') {
+  // This function is only called by on_06 if it looks like a chat command (starts with $, or @ on 11/2000, or
+  // s->chat_command_sentinel if overridden), so we just normalize all commands to $ here
+  if (!cmd.name.empty()) {
     cmd.name[0] = '$';
   }
 

src/ProxyCommands.cc

@@ -1972,7 +1972,10 @@ static asio::awaitable<HandlerResult> C_06(shared_ptr<Client> c, Channel::Messag
       co_return HandlerResult::FORWARD;
     }
 
-    char command_sentinel = (c->version() == Version::DC_11_2000) ? '@' : '$';
+    auto s = c->require_server_state();
+    char command_sentinel = s->chat_command_sentinel
+        ? s->chat_command_sentinel
+        : ((c->version() == Version::DC_11_2000) ? '@' : '$');
     bool is_command = (text[0] == command_sentinel) ||
         (text[0] == '\t' && text[1] != 'C' && text[2] == command_sentinel);
     if (is_command && c->check_flag(Client::Flag::PROXY_CHAT_COMMANDS_ENABLED)) {

src/ReceiveCommands.cc

@@ -3628,7 +3628,10 @@ static asio::awaitable<void> on_06(shared_ptr<Client> c, Channel::Message& msg)
     co_return;
   }
 
-  char command_sentinel = (c->version() == Version::DC_11_2000) ? '@' : '$';
+  auto s = c->require_server_state();
+  char command_sentinel = s->chat_command_sentinel
+      ? s->chat_command_sentinel
+      : ((c->version() == Version::DC_11_2000) ? '@' : '$');
   if ((text[0] == command_sentinel) && c->can_use_chat_commands()) {
     if (text[1] == command_sentinel) {
       text = text.substr(1);

src/ServerState.cc

@@ -1114,6 +1114,14 @@ void ServerState::load_config_early() {
   }
 
   this->enable_chat_commands = this->config_json->get_bool("EnableChatCommands", true);
+  try {
+    const auto& s = this->config_json->get_string("ChatCommandSentinel");
+    if (s.size() != 1) {
+      throw std::runtime_error("ChatCommandSentinel must be a string of length 1");
+    }
+    this->chat_command_sentinel = s[0];
+  } catch (const std::out_of_range&) {
+  }
   this->num_backup_character_slots = this->config_json->get_int("BackupCharacterSlots", 16);
 
   this->version_name_colors.reset();

src/ServerState.hh

@@ -115,6 +115,7 @@ struct ServerState : public std::enable_shared_from_this<ServerState> {
   bool use_temp_accounts_for_prototypes = true;
   std::array<uint16_t, NUM_VERSIONS> compatibility_groups = {};
   bool enable_chat_commands = true;
+  char chat_command_sentinel = '\0'; // 0 = default (@ on 11/2000; $ on all other versions)
   size_t num_backup_character_slots = 16;
   std::unique_ptr<std::array<uint32_t, NUM_NON_PATCH_VERSIONS>> version_name_colors;
   uint32_t client_customization_name_color = 0x00000000;

system/config.example.json

@@ -279,6 +279,10 @@
   // use chat commands.
   "EnableChatCommands": true,
 
+  // Sentinel to use for chat commands. If this is specified, chat commands are
+  // prefixed by this character instead of $.
+  // "ChatCommandSentinel": "/",
+
   // Number of backup character slots for each account, accessible with the
   // $savechar, $loadchar, and $checkchar commands. This can be any value, but
   // it's recommended to use a small number such as 16.