How to realize a function that takes as input an any number of procedures with one argument and returns another function is the composition of these procedures in Scheme.
For example:
(define (f x) (* x 2))
(define (g x) (* x 3))
(define (h x) (- x))
((comp-func f g h) 1) => -6
((comp-func f g) 1) => 6
((comp-func h) 1) => -1
((comp-func) 1) => 1
A clean solution would be
(define (comp-func . procs)
(define (comp-rec arg procs)
(if (null? procs)
arg
((car procs) (comp-rec arg (cdr procs)))))
comp-rec)
However with this solution you need to call it like this ((comp-func f g h) 1 (list f g h)).
Here is a solution that will work if you call it like in your examples, however it is a bit uglier because we need to use set! to change procs argument.
(define (comp-func . procs)
(define (comp-rec arg)
(if (null? procs)
arg
(let ((proc (car procs))
(rest (cdr procs)))
(set! procs rest)
(proc (comp-rec arg)))))
comp-rec)