Concatenate parameters and string

[Benalish]

Hello there. This code should report who cast the buff, which buff cast, and who received it

local f = CreateFrame("Frame")
f:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
f:SetScript("OnEvent", function(self, event, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, 
                                              arg11, arg12, arg13)
    if (event == "COMBAT_LOG_EVENT_UNFILTERED") then 
        if (arg2 == "SPELL_AURA_APPLIED") then --do stuffs
                end
    end
end)

What exactly do I have to write in order to get a sentence in the form "arg4 cast arg10 on arg7"?

[Fizzlemizz]

Depends but the simplest just see it in your chat frame would be:

if (arg2 == "SPELL_AURA_APPLIED") then --do stuffs
        print(arg4, "cast", arg10, "on", arg7)
end

You could use concatination:

print(arg4.."cast"..arg10.."on"..arg7)

or string format (%s is replaced with strings, see this for other replacment values:

local msg = "%s cast %s on %s"
print(string.format(msg, arg4, arg10, arg7))

or ...

The last two are useful if you are using something other than print() (like sending to the chat system)

[SDPhantom]

Also since BfA, CLEU doesn't send its payload to the event handler anymore. You need to use CombatLogGetCurrentEventInfo() to query the args now.