test.lua

local f = CreateFrame("frame")
f:SetScript("OnEvent", function(self, event, ...) if self[event] then return self[event](self, event, ...) end end)
f:RegisterEvent("PLAYER_LOGIN")

function f:PLAYER_LOGIN()
	self:RegisterEvent("QUEST_QUERY_COMPLETE")
	QueryQuestsCompleted()

	self:UnregisterEvent("PLAYER_LOGIN")
	self.PLAYER_LOGIN = nil
end


function f:QUEST_QUERY_COMPLETE()
	local x = GetQuestsCompleted()
	print("GetQuestsCompleted()", next(x))
end