How do I create and update an alist?

Question

This naive attempt did not work:

;; function_key = dict()
(setq function-key '()) 
;; function_key["evil-next-line"] = 108
(add-to-list function-key '(evil-next-line . 108))

It just exploded with a (setting-constant nil)

Answer 1

add-to-list accept a symbol as the first argument:

(add-to-list 'function-key '(evil-next-line . 108))

If your variable is lexical, you will want to use push instead:

(let ((foo ...))
  (push ... foo))

NB. You might want to consider Hash Tables instead of alists for lookup (they correspond to dict in Python).

Answer 2

In addition to sds's suggestion of add-to-list, you can also use push, which doesn't require you to quote the variable:

(push '(evil-next-line . 108) function-key)