number-positive-or-zero -- r7rs Type number-zero;complex-zero;real-zero;rational-zero;integer-zero;exact-integer-zero;number-positive-not-inf;real-positive;real-positive-not-inf;rational-positive;integer-positive;exact-integer-positive;real-positive-or-zero-not-inf;rational-positive-or-zero;integer-positive-or-zero;exact-integer-positive-or-zero;code-point-unicode;code-point-ascii;range-value;range-offset;range-start;range-end;range-length;range-length-zero;range-length-not-zero;byte;byte-ascii;(lambda (value) (and (number? value) (or (positive? value) (zero? value))))