Add support for IRCv3 message tags

doc/irc.luadoc

@@ -125,6 +125,7 @@ function irc:shutdown()
 
 --- Class representing an IRC message.  Objects of this class may contain the following fields:
 -- <ul>
+-- <li><code>tags</code> - A table of IRCv3 tags.</li>
 -- <li><code>prefix</code> - Prefix of the message.</li>
 -- <li><code>user</code> - A User object describing the sender of the message.</li>
 -- <li><code>command</code> - The IRC command.</li>

messages.lua

@@ -1,6 +1,7 @@
 local assert = assert
 local setmetatable = setmetatable
 local unpack = unpack
+local pairs = pairs
 
 module "irc"
 
@@ -17,7 +18,28 @@ function Message(cmd, args)
 end
 
 function msg_meta:toRFC1459()
-	s = self.command
+	s = ""
+
+	if self.tags then
+		s = s.."@"
+		for key, value in pairs(self.tags) do
+			s = s..key
+			if value ~= true then
+				assert(not value:find("[%z\07\r\n; ]"),
+					"NUL, BELL, CR, LF, semicolon, and"
+					.." space are not allowed in RFC1459"
+					.." formated tag values.")
+				s = s.."="..value
+			end
+			s = s..";"
+		end
+		-- Strip trailing semicolon
+		s = s:sub(1, -2)
+		s = s.." "
+	end
+
+	s = s..self.command
+
 	argnum = #self.args
 	for i = 1, argnum do
 		local arg = self.args[i]
@@ -33,6 +55,7 @@ function msg_meta:toRFC1459()
 		end
 		s = s..arg
 	end
+
 	return s
 end
 

util.lua

@@ -14,8 +14,25 @@ module "irc"
 function parse(line)
 	local msg = Message()
 
+	-- IRCv3 tags
+	if line:sub(1, 1) == "@" then
+		msg.tags = {}
+		local space = line:find(" ", 1, true)
+		-- For each semicolon-delimited section from after
+		-- the @ character to before the space character.
+		for tag in line:sub(2, space - 1):gmatch("([^;]+)") do
+			local eq = tag:find("=", 1, true)
+			if eq then
+				msg.tags[tag:sub(1, eq - 1)] = tag:sub(eq + 1)
+			else
+				msg.tags[tag] = true
+			end
+		end
+		line = line:sub(space + 1)
+	end
+
 	if line:sub(1, 1) == ":" then
-		local space = line:find(" ")
+		local space = line:find(" ", 1, true)
 		msg.prefix = line:sub(2, space - 1)
 		msg.user = parsePrefix(msg.prefix)
 		line = line:sub(space + 1)