;;; caps-back.el --- One-keystroke word pre-capitalizer -*- lexical-binding: t -*-
;;
;; Author: Emanuel Berg <incal@dataswamp.org>
;; Created: 2021-05-23
;; Keywords: unix
;; License: GPL3+
;; Package-Requires: ((emacs "24.1"))
;; URL: https://dataswamp.org/~incal/emacs-init/caps-back.el
;; Version: 2.1.10
;;
;;; Commentary:
;;
;; This minor mode capitalizes the entire next word that is
;; typed, at the same time as it is typed, then quietly
;; disables itself at the word boundary.
;;
;; For this to work efficiently, a short and close keystroke,
;; optimally a single key, should be assigned to invoke the
;; minor mode, which happens with the
;; `toggle-caps-mode' function.
;;
;; Setup a shortcut like this:
;;
;;   (keymap-global-set KEY #'toggle-caps-mode)
;;
;; Then, hit \\[toggle-caps-mode] and type one and only one
;; WORD in caps.
;;
;;; Code:

(defun char-alphanum-or-dash (c)
  "True if C is a character, a number, a dash, or an underscore."
  (or (member c '(?- ?_))
      (member c '(?å ?Å ?ä ?Ä ?ö ?Ö))
      (and (>= c ?1) (<= c ?9))
      (and (>= c ?A) (<= c ?Z))
      (and (>= c ?a) (<= c ?z))))

(defun caps-mode-self-insert-command (&optional times)
  "Insert the `last-command-event' char 1 or TIMES times.
Uppercase unless something else than an alphanum or a dash."
  (interactive "p")
  (or times (setq times 1))
  (let*((chr last-command-event)
        (alphanum-or-dash (char-alphanum-or-dash chr)))
    (if alphanum-or-dash
        (insert-char
          (if (= chr ?-)
              ?_
            (upcase chr))
          times)
      (caps-mode 0)
      (insert-char chr times))))

(defvar caps-mode-map
  (let ((map (make-keymap)))
    (keymap-substitute map #'self-insert-command
                           #'caps-mode-self-insert-command
                           global-map)
    map))

(define-minor-mode caps-mode
  "Caps on you."
  :init-value nil
  :lighter " Caps")

(defun toggle-caps-mode ()
  "Toggle Caps mode."
  (interactive)
  (caps-mode 'toggle))

(provide 'caps-back)
;;; caps-back.el ends here