[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
verify ISSN (issn-verify.el)
From: |
Emanuel Berg |
Subject: |
verify ISSN (issn-verify.el) |
Date: |
Fri, 11 Sep 2020 05:29:36 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) |
;;; issn-verify.el --- verify ISSN -*- lexical-binding: t
;;
;;; Commentary:
;;
;; This Elisp package provides functions to verify
;; ISSN by computing their check digits.
;;
;; Author: Emanuel Berg (incal) <moasenwood@zoho.eu>
;; Created: 2020-09-06
;; Keywords: bib, tex
;; License: GPL3+
;; Package-Requires: ((cl-lib "1.0"))
;; URL: https://dataswamp.org/~incal/emacs-init/issn-verify.el
;; Version: 1.0.0
;;
;; Also see:
;;
;; https://dataswamp.org/~incal/emacs-init/isbn-verify.el
;;
;; To install this package, with this file in
;; a buffer, do:
;;
;; M-x load-file RET RET
;;
;; International Standard Serial Number:
;;
;; ISO 3297, 1975
;;
;; format:
;;
;; The Ring Magazine: ISSN 0035-5410
;; d_1d_2d_3d_4-d_5d_6d_7c
;; d_i for i \in [1, 7] is an integer
;; c, the check digit, is 0..9 or X for 10
;;
;; compute check digit c:
;;
;; c' = 8d_1*7d_2*6d_3*5d_4*4d_5*3d_6*2d_7 mod 11
;;
;; { 0 c' = 0
;; c = {
;; { 11 - c' else
;;
;;; Code:
(require 'cl-lib)
(defun issn--get-digits (issn)
(when (string-match "[[:digit:]]\\{4\\}-[[:digit:]]\\{3\\}[X[:digit:]]" issn)
(let*((hyphen-pos 4)
(issn-lst (string-to-list issn)) )
(mapcar (lambda (c) (if (eq ?X c) "X" (- c ?0)))
(append (cl-subseq issn-lst 0 hyphen-pos)
(cl-subseq issn-lst (1+ hyphen-pos)) )))))
(defun issn-verify-issn (issn)
(let*((issn-lst (issn--get-digits issn))
(c-prop (car (last issn-lst)))
(c-w 0) )
(cl-loop for d in issn-lst
for w downfrom 8 to 2
do (cl-incf c-w (* w d)) )
(let*((c-prime (mod c-w 11))
(c (cond ((= c-prime 0) 0)
(t (- 11 c-prime) )))
(c-x (if (= 10 c) "X" c)) )
(if (equal c-prop c-x)
(message "%s (OK)" c-x)
(message "NOT OK! is %s, should be %s" c-prop c-x) ))))
;; Bicycle Quarterly (issn-verify-issn "1941-8809")
;; Bicycling (issn-verify-issn "1651-9744")
;; Black Belt (issn-verify-issn "0277-3066")
;; Filter (issn-verify-issn "1654-9813")
;; Linux Pro (issn-verify-issn "1471-5678")
;; National Geographic (issn-verify-issn "2535-4124")
;; Outside (issn-verify-issn "0278-1433")
;; The Ring (issn-verify-issn "0035-5410")
;; The Economist (issn-verify-issn "0013-0614") ; NOT OK! is 4, should be
3
(provide 'issn-verify)
;;; issn-verify.el ends here
--
underground experts united
http://user.it.uu.se/~embe8573
https://dataswamp.org/~incal
- verify ISSN (issn-verify.el),
Emanuel Berg <=