How to calculate a point N lines from another point in elisp?

Question

Given a point, how can I get the point N lines before/after it?

Will post own answer, but I'm not sure it's optimal.

Yes, using save-excursion and motion (go there and get point) is what is used. Some motion functions are more efficient than others. forward-line is efficient, for example. — Drew, Jul 20 '19 at 16:50

ideasman42 · Accepted Answer · 2019-07-20 05:45:59Z

5

This can be done using save-excursion, then moving the cursor.

(defun point-calc-lines-offset (pt lines)
  (save-excursion
    (goto-char pt)
    (forward-line lines)
    (point))

answered Jul 20 '19 at 5:45

ideasman42

4,6311 gold badge12 silver badges48 bronze badges

add a comment |

1 Answer 1