Question

I’m trying to write a function that will:

1. If there is no region selected, then kill the current line.
2. If there a region selected, then kill the rectangle between point and mark.

By (2) I mean the same thing that happens if you run M-x kill-rectangle.

Here is my attempt at the function:

(defun cut-line-or-rectangle ()
  "Cut rectangle if selection exists, cut line otherwise"
  (interactive)
  (if mark-active
      (kill-rectangle (point) (mark))
    (kill-whole-line)
  )
)

This fullfils (1) but does nothing if a region is active. How can I make emacs obey the kill-rectangle function in this circumstance?

Answer 1

kill-rectangle takes start and end in that order, so your code only works when point < mark.

The typical way to do this sort of thing is to give your function start and end arguments, and then use (interactive "r").