zap-to-over

zap-to-over.el

"
Bline lineM line lineE
K  C      D

D = C + BM - KC

asks for a template
finds M and yields M - C as offset

TODO: only moves to the first match.
TODO: iron out error cases
"

(defvar DEBUG t)

(defun debug (fmt &rest args)
  (when DEBUG (apply #'message (cons fmt args))))

(defun zap-to-over (s &optional space)
  (interactive "s> ")
  (let* ((space (or space ?\s))
	 (c (point))
	 (b (line-beginning-position 0))
	 (k (line-beginning-position 1))
	 (m (save-excursion
	      (goto-char b)
	      (when (re-search-forward s nil t)
		(- (point) (length s))))))
    (if m
	(let* ((bm (- m b))
	       (kc (- c k))
	       (np (+ c (- bm kc))))
	  (progn
	    (debug "< %s (c:%d bm:%d kc:%d np:%d)" s c bm kc np)
	    (insert (make-string (- np (point)) space))))
      (message "no match"))))

(defalias 'align-to #'zap-to-over)
(defalias 'align-below #'zap-to-over)