(defn
nat-int?
"Return true if x satisfies int? and is a natural integer value."
[x]
(cond
(integer? x)
(or (not (neg? x)) (zero? x))
(instance? goog.math.Integer x)
(or (not (.isNegative x)) (.isZero x))
(instance? goog.math.Long x)
(or (not (.isNegative x)) (.isZero x))
:else
false))