(1) In make-random-char-generator and in make-random-string-generator, the "string" argument should be a non-empty string, which isn't stated explicitly.

(2) In make-random-integer-generator, may the arguments be inexact and/or real numbers or do they have to be exact integers?

(3) "Is it an error" in the sense of R7RS the sets to draw random elements from are empty as in (make-random-integer-generator 1 0)?

PS A version of make-random-complex-generator, which generates random complex numbers uniformly distributed over a disc or annulus (instead of a square) would be much much more useful for applications. Could we add such a version? It could be make-random-complex-generator called with three parameters: A complex number (the origin), a minimum radius and a maximum radius.