;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/beer.el

(defun beer2beer (alc-src &optional alc-dst num vol-src vol-dst)
  (or alc-dst (setq alc-dst alc-src))
  (or num (setq num 1))
  (let ((vol-std 50))
    (or vol-src (setq vol-src vol-std))
    (or vol-dst (setq vol-dst vol-std)) )
  (/ (* alc-src vol-src num)
     (* alc-dst vol-dst) ))

;; (+ (beer2beer 3.5 5.3) (beer2beer 2.8 5.3 2) (beer2beer 4.0 5.3 2 27.5))
;; (beer2beer 12 5.3 2 20)
;; (beer2beer 12 5.3 1 75)

;; (beer2beer 5.3 nil 5 33) ; 5 33cl 5.3% = 3.3 50cl 5.3%

;; (beer2beer 1.8 5.3 6) ; 2.0 - lättöl   (1.8%)
;; (beer2beer 2.8 5.3 6) ; 3.2 - två-åtta (2.8%)
;; (beer2beer 3.5 5.3 6) ; 4.0 - folköl   (3.5%)
;; (beer2beer 4.2 5.3 6) ; 4.8 - mellanöl (4.2%)
;; (beer2beer 5.3 5.3 6) ; 6.0 - starköl  (5.3%)
;; (beer2beer 7.2 5.3 6) ; 8.2 - sju-tvåa (7.2%)

(provide 'beer)