added callbacks to block or otherwise process messages from other mods

doc/API.txt

@@ -12,7 +12,6 @@ In order to allow your mod to interface with this mod, you must add `irc'
 
 REFERENCE
 ---------
-These are the functions defined by the mod:
 
 mt_irc.say ( [name ,] message )
   Sends <message> to either the channel (if <name> is nil or not specified),
@@ -40,6 +39,77 @@ mt_irc.register_bot_command ( name, cmddef )
       params = nil, -- No params
       description = "Greet user",
       func = function ( from, param )
-        mt_irc.say(from, "Hello!");
+        mt_irc.say(from, "Hello!")
       end,
     });
+
+mt_irc.connected_players [ name ]
+  This table holds the players who are currently on the channel (may be less
+   than the players in the game). It is modified by the /part and /join chat
+   commands.
+  Example:
+    if (mt_irc.connected_players["joe"]) then
+      -- Joe is talking on IRC
+    end
+
+mt_irc.register_callback ( name, func )
+  Registers a function to be called when an event happens. <name> is the name
+   of the event, and <func> is the function to be called. See CALLBACKS below
+   for more information
+  Example:
+    mt_irc.register_callback("channel_msg", function ( from, msg )
+      if (from == "joe") then
+        mt_irc.say("joe", "You are not allowed to do that!")
+        return true
+      end
+    end)
+
+This mod also supplies some utility functions:
+
+string.expandvars ( string, vars )
+  Expands all occurrences of the pattern "$(varname)" with the value of
+   `varname' in the <vars> table. Variable names not found on the table
+   are left verbatim in the string.
+  Example:
+    local tpl = "$(foo) $(bar) $(baz)"
+    local s = tpl:expandvars({ foo=1, bar="Hello" })
+    -- `s' now contains "1 Hello $(baz)" 
+
+In addition, all the configuration options decribed in `README.txt' are
+ available to other mods, though they should be considered "read only". Do
+ not modify these settings at runtime or you will most likely crash the
+ server!
+
+
+CALLBACKS
+---------
+The `mt_irc.register_callback' function can register functions to be called
+ when some events happen. These are the events supported:
+
+channel_msg ( from, message )
+  Called right before the bot sends a message to the channel.
+  <from> is the name of the user sending the message. <message> is the
+   unmodified message sent by the user.
+  Returning any value other than nil or false will prevent the message from
+   being sent.
+  Example:
+    mt_irc.register_callback("channel_msg", function ( from, msg )
+      if (from == "joe") then
+        mt_irc.say("joe", "You are not allowed to do that!")
+        return true
+      end
+    end)
+
+private_msg ( from, to, message )
+  Called right before the bot sends a private message to an user.
+  <from> is the name of the user sending the message. <to> is the recipient
+   of the message. <message> is the unmodified message sent by the user.
+  Returning any value other than nil or false will prevent the message from
+   being sent.
+  Example:
+    mt_irc.register_callback("private_msg", function ( from, to, msg )
+      if (to == "admin") then
+        mt_irc.say(from, "You are not allowed to do that!")
+        return true
+      end
+    end)

src/callback.lua

@@ -13,6 +13,26 @@
 
 local irc = require("irc");
 
+mt_irc.callbacks = { };
+
+mt_irc._callback = function ( name, ... )
+    local list = mt_irc.callbacks[name];
+    if (not list) then return; end
+    for n = 1, #list do
+        local r = list[n](...);
+        if (r) then return r; end
+    end
+end
+
+mt_irc.register_callback = function ( name, func )
+    local list = mt_irc.callbacks[name];
+    if (not list) then
+        list = { };
+        mt_irc.callbacks[name] = list;
+    end
+    list[#list + 1] = func;
+end
+
 minetest.register_on_joinplayer(function ( player )
 
     mt_irc.say(mt_irc.channel, "*** "..player:get_player_name().." joined the game");
@@ -35,6 +55,7 @@ irc.register_callback("channel_msg", function ( channel, from, message )
         channel=mt_irc.channel;
     };
     local text = mt_irc.message_format_in:gsub("%$%(([^)]+)%)", t)
+    if (mt_irc._callback("channel_msg", from, message, text)) then return; end
     for k, v in pairs(mt_irc.connected_players) do
         if (v) then minetest.chat_send_player(k, text); end
     end
@@ -89,7 +110,8 @@ irc.register_callback("private_msg", function ( from, message )
         port=mt_irc.port;
         channel=mt_irc.channel;
     };
-    local text = mt_irc.message_format_in:gsub("%$%(([^)]+)%)", t)
+    local text = mt_irc.message_format_in:expandvars(t);
+    if (mt_irc._callback("private_msg", from, player_to, message, text)) then return; end
     minetest.chat_send_player(player_to, "PRIVATE: "..text);
 end);
 

src/chatcmds.lua

@@ -30,7 +30,7 @@ minetest.register_chatcommand("msg", {
             name=name;
             message=msg;
         };
-        local text = mt_irc.message_format_out:gsub("%$%(([^)]+)%)", t)
+        local text = mt_irc.message_format_out:expandvars(t);
         irc.send("PRIVMSG", name, text);
     end;
 });

src/init.lua

@@ -116,7 +116,7 @@ mt_irc.connect = function ( )
                         name=(msg.name or "<BUG:no one is saying this>");
                         message=(msg.message or "<BUG:there is no message>");
                     };
-                    local text = mt_irc.message_format_out:gsub("%$%(([^)]+)%)", t)
+                    local text = mt_irc.message_format_out:expandvars(t);
                     irc.say(mt_irc.channel, text);
                 end
                 mt_irc.buffered_messages = nil;
@@ -145,6 +145,13 @@ end
 
 mt_irc.irc = irc;
 
+-- Misc helpers
+
+-- Requested by Exio
+string.expandvars = function ( s, vars )
+    return s:gsub("%$%(([^)]+)%)", vars);
+end
+
 dofile(MODPATH.."/callback.lua");
 dofile(MODPATH.."/chatcmds.lua");
 dofile(MODPATH.."/botcmds.lua");