Question

I am having problems with a scheme function.

(define myfun(operator lis)
   (if(null? lis)
     '()
    (cons(operator (car lis)(car lis))myfun(operator (cdr lis))
))))

The function takes an operator as an parameter and a list for example (+'(1 2 3 4))
and the error i get when i try to call the function is : expecting a number but received a list. So my question is how do i call a function recursively with an operator and a list?

UPDATE: just needed a ' sign before the operator.

Answer 1

Just pass + to the function, without any quoting. + denotes the addition function.

(define (apply-op op x)
  (op x x))

will perform

(apply-op + 2)  ==>  4