- tuple-ref tup nprocedure
function (result)
(tuple-ref tup n) requires (and (%tuple? tup) (cardinal? n) (< -1 n (%tuple-length tup))) ensures "tup's nth item"
function (result)
(tuple-ref tup n) requires (and (%tuple? tup) (cardinal? n) (< -1 n (%tuple-length tup))) ensures "tup's nth item"