;;; -*- lexical-binding: t -*-
;;;
;;; this file:
;;;   http://user.it.uu.se/~embe8573/emacs-init/align-new.el
;;;   https://dataswamp.org/~incal/emacs-init/align-new.el

(require 'my-string)

(defun insert-at-col (str col)
  (interactive "s string: \nncol: ")
  (let*((beg-col (or (current-column) 0))
        (step    (- col beg-col)) )
    (when (> step 0)
      (insert (make-string step ?\s) str) )))

(defun pad-to-col (&optional set-new-col)
  (interactive "p")
  (let*((plist   (symbol-plist #'pad-to-col))
        (prop    'pad-col)
        (pad-col (or (plist-get plist prop) 0))
        (beg-col (or (current-column) 4)) )
    (if (and set-new-col (= 4 set-new-col))
        (progn
          (plist-put plist prop beg-col)
          (message "pad col set: %s" beg-col) )
      (let ((step (- pad-col beg-col)))
        (when (> step 0)
          (insert (make-string step ?\s))
          (forward-line 1)
          (forward-char beg-col) )))))

(defun eat-space ()
  "When on a blank line, `delete-blank-lines'.
Else, if spaces and/or tabs are to the _right_ of point, delete them.
Else, ditto _left_, but save one whitespace."
  (interactive)
  (let ((start (point))
        (same-line-whitespace " \t") )
    (beginning-of-line)
    (if (looking-at (format "^[%s]*$" same-line-whitespace))
        (delete-blank-lines)
      (goto-char start)
      (if (= 0 (skip-chars-forward same-line-whitespace))
          (progn
            (delete-horizontal-space)
            (insert "\s") )
        (delete-region start (point)) ))))

(defconst stop-char-default "\\(^\\|[[:punct:]]\\|[[:space:]][[:alnum:]]\\)")
(defvar   stop-char stop-char-default)

(defun align-from-left (&optional set-char)
  (interactive "p")
  (let ((start (point)))
    (if (= 4 set-char) ; set stop-char
        (setq stop-char (regexp-quote (char-to-string (read-char))))
      (when (= 16 set-char) ; reset stop-char
          (setq stop-char stop-char-default) ))
(re-search-backward stop-char (line-beginning-position) t) ; NOERROR
    (let*((hit-str-prop (substring-no-properties (match-string 0)))
          (hit-str (unless (empty-string-p hit-str-prop)
                     (substring hit-str-prop 0 1))))
      (when (empty-string-p hit-str) (forward-char 1)))
    (insert (make-string (- start (point)) ?\s)) ))

(provide 'align-new)