- (def-frob zerop "Returns T if number = 0, NIL otherwise.")
- (def-frob plusp "Returns T if number > 0, NIL otherwise.")
- (def-frob minusp "Returns T if number < 0, NIL otherwise.")
- (def-frob oddp "Returns T if number is odd, NIL otherwise.")
- (def-frob evenp "Returns T if number is even, NIL otherwise."))
+ (def-frob zerop "Is this number zero?")
+ (def-frob plusp "Is this real number strictly positive?")
+ (def-frob minusp "Is this real number strictly negative?")
+ (def-frob oddp "Is this integer odd?")
+ (def-frob evenp "Is this integer even?"))