In SRFI-48,

Examples
...

(format #f "~a ~? ~a ~%" 3 " ~s ~s " '(2 2) 3)
; =>
"3  2 2  3
"

(format "~w" (let ( (c '(a b c)) ) (set-cdr! (cddr c) c) c))
; => "#1=(a b c . #1#)"

(format "~8,2F" 32)
; => "   32.00"

(format "~8,3F" (sqrt -3.8))
; => "0.000+1.949i"

(format "~8,2F" 3.4567e11)
; => " 3.45e11"                    ----> Why not " 3.46e11"?

(format "~6,3F" 1/3)
; => " 0.333"

--
INITERM