Question

I need to select text in Emacs with regexp. And it would be for the best if I had an option to match only if match is surrounding caret.

Example:

text.....

<start oftext I want to select> text.....
text....
text.... <caret> text....
text....
text.... <end of text I want to select>

some other text

Edit: I am sorry that I obviously didn’t state my question clearly, so here is a clarification:

• Caret was meant as the place where cursor is currently placed, not literal text to be matched
• Start and end of text to be selected is just all the text that is in the document without any empty line.

Answer 1

It’s not hard to find something around point in elisp. Just use two searches, forward and backward.

(defun set-selection-around-parens()
  (interactive)
  (let ( (right-paren (save-excursion ; using save-excursion because
                                      ; we don't want to move the
                                      ; point.
                        (re-search-forward ")" nil t))) ; bound nil
                                                        ; no-error t
         (left-paren (save-excursion (re-search-backward "(" nil t))))
  (when (and right-paren left-paren)
    ;; this is actually a way to activate a mark
    ;; you have to move your point to one side
    (push-mark right-paren)
    (goto-char left-paren)
    (activate-mark))))

When you use primary selection to select something around, you can’t save the position of your current point(you named it caret). To save current position and have some selection, you can use secondary selection.

(require 'second-sel)
(global-set-key [(control meta ?y)]     'secondary-dwim)
(define-key esc-map "y"                 'yank-pop-commands)
(define-key isearch-mode-map "\C-\M-y"  'isearch-yank-secondary)

(defun secondary-selection-deactivate()
  (interactive)
  (x-set-selection 'SECONDARY nil)
  (move-overlay mouse-secondary-overlay (point-min) (point-min) (current-buffer)))

(defun secondary-selection-in-this-buffer-p()
  (and (x-get-selection 'SECONDARY) (overlayp mouse-secondary-overlay) (eq (current-buffer) (overlay-buffer mouse-secondary-overlay))))

(defun set-secondary-selection-around-parens()
  (interactive)
  (let ( (right-paren (save-excursion (re-search-forward ")" nil t)))
         (left-paren (save-excursion (re-search-backward "(" nil t))))
  (when (and right-paren left-paren)
    (primary-to-secondary left-paren right-paren)
    )))