How to use `initial-scratch-message` variable to display mutliple status informations after start

Question

I want to use the scratch buffer to display some status informations after starting emacs. I read I can use initial-scratch-message variable for this.

But I do not know how to set it up.

Here you see a function(?) that gives back the start-up-time as a string. And with emacs-startup-hook it is well displayed in the statusbar. But the same with initial-scratch-message it does not work. I tried `display-graphic-p' too. And how would I append informations/values to that variable instead of just overwriting it?

;; === Print start-time after start
; from https://github.com/daviwil/emacs-from-scratch/blob/master/show-notes/Emacs-Scratch-12.org
(defun efs/display-startup-time ()
  (message "Emacs loaded in %s with %d garbage collections."
       (format "%.2f seconds"
           (float-time
           (time-subtract after-init-time before-init-time)))
       gcs-done))
(add-hook 'emacs-startup-hook #'efs/display-startup-time)

(initial-scratch-message #'efs/display-startup-time)
; this does not work also (wront type argument stringp)
; (setq initial-scratch-message #'efs/display-startup-time)

(initial-scratch-message display-graphic-p)

; Would prefere this (Python-Lisp-Pseudo-Code)
;(initial-scratch-message 'display-graphic-p is "{}".format(display-graphic-p))

Answer 1

Functions that end with 'p' are predicates, which in emacs-speak means they check for something. In this case, display-graphic-p checks to see if you're invoking emacs in a terminal or in a graphical display. "Return non-nil if DISPLAY is a graphic display." Have you looked at the Dashboard package? It may provide what you're looking for.

Answer 2

This solve a part of the problem. Keep in mind that efs/display-startup-time is a function.

(setq initial-scratch-message (efs/display-startup-time))

But display-graphic-p (which is a "compiled function") doesn't work like that.

This is how strings can added (concated) to the variable. But I am unsure if this is the usual Lisp-way.

(setq initial-scratch-message (concat initial-scratch-message "\nfoo"))
(setq initial-scratch-message (concat initial-scratch-message "bar"))