UPDATE_FACTION fires whenever faction details change, but doesn't have any parameters, apparently.
CHAT_MSG_COMBAT_FACTION_CHANGE, on the other hand, does have information. I checked out how Ara Broker Reputations deals with it. Here's what it does:
Code:
local fsInc = FACTION_STANDING_INCREASED:gsub("%%d", "([0-9]+)"):gsub("%%s", "(.*)")
local fsDec = FACTION_STANDING_DECREASED:gsub("%%d", "([0-9]+)"):gsub("%%s", "(.*)")
function f:CHAT_MSG_COMBAT_FACTION_CHANGE(msg)
local faction, value, neg, updated = msg:match(fsInc)
if not faction then
faction, value = msg:match(fsDec)
if not faction then return end
neg = true
end
if tonumber(faction) then faction, value = value, tonumber(faction) else value = tonumber(value) end
-- ...
end
So, I suppose you could do that stuff pretty easily.