Question

How would you update a list by removing the first item?

consider the following pseudocode

define remover
(list = cdr list))

or is there a more recommendable way of removing the first item in a list?

Answer 1

You nailed it, just write it as a procedure:

(define (remover lst)
  (cdr l))

And use it like this (this creates a new binding, and is not an assignment):

(let ((new-list (remover old-list)))
  new-list)

Or like this (this defines a new list):

(define new-list (remover old-list))

In any case, be aware that the original list passed as a parameter to remover will not be modified, instead a new list will be returned without the first element of the old list; that’s the way to operate on immutable linked lists, you should never assume that any modifications on a list will occur in-place.