;;; -*- lexical-binding: t -*-
(require 'deferred)
(defvar marquee-deferred-chain nil)
(defvar marquee-count 0)

(defun marquee-string (str delay)
  (setq marquee-count 0)
  (setq marquee-deferred-chain
        (deferred:loop 29999
          (lambda (i)
            (deferred:$
              (deferred:next
                (lambda ()
                  (message "%s" (truncate-string-to-width (substring (concat str " " str " " str) (mod i (length str)))
                                                          (- (frame-width) 1) 0))))
              (deferred:wait (* 1000 delay)))))))

;; (marquee-string "foobarbaz" 0.2)
;; (marquee-cancel)
(defun marquee-cancel ()
  (interactive)
  (when marquee-deferred-chain (deferred:cancel marquee-deferred-chain))
  (setq marquee-deferred-chain nil))

(provide 'mylisp-marquee)