custom--sort-vars

code: custom.el

(defun custom--sort-vars (vars)

"Sort VARS based on custom dependencies.

VARS is a list whose elements have the same form as the ARGS

arguments to `custom-theme-set-variables'. Return the sorted

list, in which A occurs before B if B was defined with a

(let ((custom--sort-vars-table (make-hash-table))

(dependants (make-hash-table))

(custom--sort-vars-result nil)

last)

;; Construct a pair of tables keyed with the symbols of VARS.

(dolist (var vars)

(puthash (car var) (cons t var) custom--sort-vars-table)

(puthash (car var) var dependants))

;; From the second table, remove symbols that are depended-on.

(dolist (var vars)

(dolist (dep (get (car var) 'custom-dependencies))

(remhash dep dependants)))

;; If a variable is "stand-alone", put it last if it's a minor

;; mode or has a :require flag. This is not really necessary, but

;; putting minor modes last helps ensure that the mode function

;; sees other customized values rather than default values.

(maphash (lambda (sym var)

(when (and (null (get sym 'custom-dependencies))

(or (nth 3 var)

(eq (get sym 'custom-set)

'custom-set-minor-mode)))

(remhash sym dependants)

(push var last)))

dependants)

;; The remaining symbols depend on others but are not

;; depended-upon. Do a depth-first topological sort.

(nreverse (append last custom--sort-vars-result))))