How to parse a right click in computercraft?

I'm working on an OS and I have a piece of code that parses input from the user and I can't figure out how to tell the difference between a left- and right-click. This is my code so far:

while true do
local event, button, X, Y = os.pullEventRaw()
if slc == 0 then
if event == "mouse_click" then
if X >= 2 and X <= 4 and Y == 1 and button == 1 then
term.clear ()

elseif X >= 5 and X <= 8 and Y >= 17 and Y <= 19 and button == 1 then
shell.run ("/Falchion/Prg/quest.FEF")

elseif X >= 10 and X <= 14 and Y >= 17 and Y <= 19 and button == 1 then
shell.run ("/Falchion/Prg/Sketch.FEF")

elseif X >= 15 and X <= 19 and Y >= 17 and Y <= 19 and button == 1 then
shell.run ("/Falchion/Prg/ink.FEF")

elseif X >= 20 and X <= 24 and Y >= 17 and Y <= 19 and button == 1 then
shell.run ("/Falchion/Prg/table.FEF")

elseif X == 50 and Y == 1 and button == 1 then
prompt (shutdown)

elseif X == 50 and Y == 1 and button == 2 then -- I took a guess, but that didn't work.
prompt (powMenu)

else drawGUI ()

end

end

end

end

Any help would be appreciated. Thank you.

Yep. That's how you do it. What made you think it didn't work?

You're passing in a nil variable to the function I think.

Lyqyd, on 27 November 2014 - 10:28 PM said:

Yep. That's how you do it. What made you think it didn't work?

It would do the same thing as if I had left-clicked it.

awsumben13, on 27 November 2014 - 10:44 PM said:

You're passing in a nil variable to the function I think.

I actually am passing a nil argument, But I was expecting it to do nothing or return an error, not do the same thing as that which happens at a left-click. I'll finish adding in the other args and see if it works then.

Is shutdown also nil? Passing two different nils won't do anything different in the function.