Convert a word into an acronym

Question

I have a buffer with this line of text:

This is a random test

I want to convert test in T.E.S.T., like this:

This is a random T.E.S.T.

So far, I came up with this function:

(defun mu-convert-to-acronym (string)
  "Convert the given STRING in an acronym.
An acronym must be uppercase and have each letter followed by a dot."
  (s-upcase
   (s-append "."
             (s-join "."
                     (delete ""
                             (s-split "" string))))))

My question is: how can I turn this function into a command I can call interactively?

I'd like the command to behave like capitalize-word and upcase-word, meaning I don't need to select the word I need to convert but I can just issue the command on the word next to point or, given a negative prefix, the one before point.

Answer 1

My question is: how can I turn this function into a command I can call interactively?

Use the special form interactive, also see manual (elisp) Defining Commands.

Here is a command named foo which uses your mu-convert-to-acronym.

(defun foo (arg)
  "Convert word at (or next to) point to its acronym with `mu-convert-to-acronym'.
With numerical argument ARG, convert the next ARG-1 words as well.

With negative argument, convert previous words."
  (interactive "p")
  ;; With negative argument, move back point firstly
  (when (< arg 0)
    ;; If point is in a word but not at the beginning of that word,
    ;; then move to the beginning fistly
    (let ((bounds (bounds-of-thing-at-point 'word)))
      (when (and bounds (not (= (car bounds) (point))))
        (forward-word -1)))
    (forward-word arg))
  (dotimes (_ (abs arg))
    ;; Adjust point in case point isn't on any word
    (forward-word)
    (backward-word)
    (let ((bounds (bounds-of-thing-at-point 'word)))
      (when bounds
        (let* ((beg (car bounds))
               (end (cdr bounds))
               (str (buffer-substring beg end)))
          (delete-region beg end)
          (goto-char beg)
          (insert (mu-convert-to-acronym str)))))))

Answer 2

Here it is:

(require 's)

(defun mu--convert-word-to-acronym (string)
  "Convert the given STRING in an acronym.
An acronym must be uppercase and have each letter followed by a dot."
  (insert (s-upcase
           (s-append "."
                     (s-join "."
                             (delete ""
                                     (s-split "" string)))))))

(defun mu-convert-word-to-acronym (arg)
  "Applies mu--convert-word-to-acronym to a word at point. With positive arg applies to the next word, with negative arg applies to the previous word"
  (interactive "P")

  (cond
   ((equal arg '(4))
    (forward-word)
    (forward-char)
    )
   ((equal arg '(-4))
    (forward-word -1)
    (forward-char -1)
    )
   ((equal arg '-)
    (forward-word -1)
    (forward-char -1)
    )
   (t
    )
   )

  (let (word-bounds word-start word-end)

    (setq word-bounds (bounds-of-thing-at-point 'word))
    (setq word-start (car word-bounds))
    (setq word-end (cdr word-bounds))

    (setq word (buffer-substring-no-properties word-start word-end))

    (delete-region word-start word-end)

    (mu--convert-word-to-acronym word)

    )

  )

Call M-x mu-convert-word-to-acronym.