http://rosettacode.org/wiki/Introspection — an Io solution exists, but makes no attempt at extra credit: Report the number of integer variables in global scope, and their sum.

introspection.io

// dumb test for int-ness, since Io doesn't have ints
// rather than being cheeky and doing Integer := Number clone
Number isInt := method(self == self roundDown)

countAndSumLobbyIntegers := method(
	_ := Lobby slotNames select(x, 
		(Lobby getSlot(x) type == "Number")
	) map(x, Lobby getSlot(x)) select(x, x isInt)

	("There are " .. (_ size) .. " integer Numbers in Lobby") println
	("Their sum is " .. (_ sum)) println
)

s := "i am a string, silly"
x := 3
y := 2.3
z := 5

countAndSumLobbyIntegers()

// Output:
// There are 2 integer Numbers in Lobby
// Their sum is 8