Selective Display question

Ravindra Viswanath writes: That would depend on the hidden-lines mode (which I don't currently have installed so I can't check it). You could add code to make the hidden lines read-only, but that would prevent changes by causing an error when using find/replace or rectangle operations. It is easy to write one function (defun hidden-lines-replace-string (from-string to-string &optional delimited) (interactive "sFind: \nsReplacement: \nP") (setq from-string (regexp-quote from-string)) (when delimited (setq from-string (concat "\\b" from-string "\\b"))) ;; Stop worrying about the "re-". ;; This is plenty efficient for interactive use. (while (re-search-forward from-string nil t) (condition-case nil (replace-match to-string) (extent-read-only (goto-char (match-end 0)))))) but I imagine there are several such functions you need. It would be possible to write a macro based on this pattern: (defmacro with-skipping-read-only-extents (self args &rest body) ;; SELF must be the name of the iterative function being defined. ;; ARGS is its argument list. ;; BODY is the implementation. `(condition-case nil (progn ,＠body) (extent-read-only (goto-char (match-end 0)) (apply self args)))) but it might not be very useful. I don't even know if (defun hidden-lines-replace-string (from-string to-string &optional delimited) (with-skipping-read-only-extents hidden-lines-replace-string (from-string to-string &optional delimited) (replace-string from-string to-string delimited))) would work correctly (replace-string may take care to save the match-data, in which case you won't have access to the needed information about the match that found read-only data), and I suspect (defun hidden-lines-kill-rectangle (start end &optional fill) (with-skipping-read-only-extents hidden-lines-kill-rectangle (start end &optional fill) (kill-rectangle start end fill))) would have rather surprising behavior. Also, this strategy based on handling the error would not work for *copying* since that doesn't try to change the read-only text. There is a library called atomic-extents which adds a property called 'atomic that prevents point from entering an atomic extent. However, apparently it doesn't work very well. Certain functions such as delete-backward-char don't respect it (see C-h f set-extent-property), and I suspect that anything written in C (such as the find/replace functions) would suffer from this. Also functions that operate on the whole region (eg, copying it) will continue to do so; by design atomic extents don't prevent access to the extent, they just require that it be treated as a whole or not at all. GNU Emacs has an 'intangible property that can be applied to text, but I seem to recall that they don't use it much, so people who try to use it often find it doesn't meet their needs. In your case, it might work for find/replace, but not for copying. Or vice versa, I don't know much more than the name and that it is more or less similar to atomic extents. Bottom line, I suspect you're going to have to write a lot of code yourself to make this work naturally, because none of the primitives are designed to skip hidden text. There's no question that it can be done, just is it worth it to you. _______________________________________________ XEmacs-Beta mailing list XEmacs-Beta(a)xemacs.org http://lists.xemacs.org/mailman/listinfo/xemacs-beta