Shrink calpi function

calpi.lua

@@ -1,19 +1,16 @@
-local calpi = function()
-	local operator = '+'
+local unpack = unpack or table.unpack
+
+local function calpi()
+	local op = true
+	local operator = "+"
 	local mypi = 0
 	for i=1, 10000000000, 2 do
-		if operator == '+' then
-			mypi = mypi + (4/i)
-			operator = '-'
-		elseif operator == '-' then
-			mypi = mypi - (4/i)
-			operator = '+'
-		end
+		mypi, op = (op and mypi+(4/i) or mypi-(4/i)), (not op and true or false)
 	end
 end
 
 start = os.clock()
-calpi()
+print(calpi())
 stop = os.clock()
 
-return (stop - start)
+print (stop - start)