System Message Parsing

[Zarah]

I apologize if this has been answered else where but I have been unable to find what I am looking for.

I am looking to parse the name of the player (PlayerX) in each of the following system messages.

PlayerX is already in a group.
PlayerX declines your group invitation.
PlayerX joins the party.
PlayerX has joined the raid group
Cannot find 'PlayerX'.

I have some hacked together code that will do this below that I have taken from another mod. It takes the entire string from CHAT_MSG_SYSTEM and looks for the space in the first 4 cases or the ' in the last one and sends me back just the name.

function RN_GetArgs(message, separator)
	-- This procedure from DKP_System by Sammysnake
	-- Declare 'args' variable.
	local args = {};

	-- Declare 'i' integer.
	i = 0;

	-- Search for seperators in the string and return
	-- the separated data.
	for value in string.gfind(message, "[^"..separator.."]+") do
		i = i + 1;
		args[i] = value;
	end -- end for

	-- Submit the filtered data.
	return args;
end -- end RN_GetArgs()

Does Blizzard provide this information already in an arg that I am missing? Is there another/better Event that I could be looking at? Or is this the best way to obtain this information?

Any information greatly appreciated as this is my first shot at a 'real' mod.

[OnmyojiOmn]

If you take a look in FrameXML\GlobalStrings.lua, you'll find all of the game's localized format strings. You use the provided format string to create a pattern, which is used to parse the message. The awesome thing about this is that it's localized, so your mod will work overseas barring other problems.

local pattern = string.format(ERR_ALREADY_IN_GROUP_S, "(%a+)")
local startIndex, endIndex, characterName = string.find(arg1, pattern)