Re: Returning no value

Ken Tilton wrote:
 

Steven M. Haflich wrote:

I think the OP may be looking for something like this:
 
cl-user(10): (defun foo()
          (let ((x (random 10)))
        (and (< 5 x) x)))
foo
cl-user(11): (loop repeat 10
        as x = (foo)
        when x collect x)   ; <<<<<
(6 8 9)

 
Sweet. But not wnat someone already offered?:
 
   (loop repeat 10
         when (foo)
         collect it)

 
Gauche Scheme
 
(use srfi-27) ;; random-integer
 
(define (foo . _) (let1 x (random-integer 10) (and (< 5 x) x)))
 
(filter-map foo (iota 10))
  ===>
(9 6 7 8 9)
 
Another way.
 
(define (foo) (let1 x (random-integer 10) (and (< 5 x) x)))
 
(filter-map (^_ (foo)) (iota 10))
  ===>
(7 8 9 6 6 7)