[plt-scheme] help on HTDP ex-9.5.8

On Sep 26, 2005, at 6:47 AM, arnuld wrote:

> (define (check-integer lon)
>   (cond
>     [(<= (first lon) 0) false]
>     [(empty? (rest lon)) true]
>     [else (check-integer (rest lon))]))

You failed to design this function. Instead you guesses and the result 
was an error.

Pls work thru the six design steps and report back what happens.

-- Matthias