;;; nuke-whitespace.el --- strip trailing whitespace from buffers -*- lexical-binding:t -*- ;; Author: Noah Friedman ;; Maintainer: [email protected] ;; Public domain. ;; $Id: nuke-whitespace.el,v 1.15 2025/04/15 06:19:24 friedman Exp $ ;;; Commentary: ;; This used to be called whitespace.el, but that now conflicts with a ;; standard emacs package which does something totally different. ;; You may wish to do the following in your .emacs: ;; ;; (autoload 'nuke-trailing-whitespace "nuke-whitespace" nil t) ;; (add-hook 'mail-send-hook 'nuke-trailing-whitespace) ;; (add-hook 'write-file-hooks 'nuke-trailing-whitespace) ;;; Code: ;;;###autoload (defvar nuke-trailing-whitespace-p 'nuke-whitespace-check-mode "*Specify when stripping whitespace should be done. This variable affects how the function `nuke-trailing-whitespace' behaves. If `t', unreservedly strip trailing whitespace, including excess newlines. If `nil', do nothing. If a symbol \(not bound to a function\), query for each instance. If a function or name of a function, call it to decide what to do. This function is called once and should return `t', `nil', or the symbol `query' to decide what to do. This variable is made buffer-local when set in any fashion.") (make-variable-buffer-local 'nuke-trailing-whitespace-p) ;; The regexp "\\s-+$" is too general, since form feeds (\n), carriage ;; returns (\r), and form feeds/page breaks (C-l) count as whitespace in ;; some syntaxes even though they serve a functional purpose in the file. (defconst nuke-trailing-whitespace-regexp "[ \t]+$" "Regular expression which matches trailing whitespace.") ;; Match two or more trailing newlines at the end of the buffer; all but ;; the first newline will be deleted. (defconst nuke-whitespace-eob-newline-regexp "\n\n+\\'" "Regular expression which matches newlines at the end of the buffer.") ;;;###autoload (defvar nuke-trailing-whitespace-always-major-modes '(ada-mode c++-mode c-mode change-log-mode cperl-mode emacs-lisp-mode fortran-mode latex-mode lisp-interaction-mode lisp-mode makefile-mode nroff-mode perl-mode plain-tex-mode prolog-mode python-mode scheme-mode sgml-mode tcl-mode slitex-mode sml-mode texinfo-mode) "*Major modes for which `nuke-whitespace-check-mode' will return `t'. These are major modes for which `nuke-trailing-whitespace' should strip all trailing whitespace and excess newlines at the end of the buffer without asking.") ;;;###autoload (defvar nuke-trailing-whitespace-never-major-modes '(mail-mode rmail-mode vm-mode vm-summary-mode) "*Major modes for which `nuke-whitespace-check-mode' will return `nil'. These are major modes for which `nuke-trailing-whitespace' should never strip trailing whitespace automatically.") ;;;###autoload (defun nuke-trailing-whitespace () "Nuke all trailing whitespace in the buffer. Whitespace in this case is just spaces or tabs. This is a useful function to put on write-file-hooks. Unless called interactively, this function uses `nuke-trailing-whitespace-p' to determine how to behave. However, even if this variable is `t', this function will query for replacement if the buffer is read-only." (interactive) (cond ((interactive-p) (call-interactively 'nuke-trailing-whitespace-doit)) (t (let ((flag nuke-trailing-whitespace-p)) (and nuke-trailing-whitespace-p (symbolp nuke-trailing-whitespace-p) (fboundp nuke-trailing-whitespace-p) (setq flag (funcall nuke-trailing-whitespace-p))) (and flag (nuke-trailing-whitespace-doit flag))))) ;; always return nil, in case this is on write-file-hooks. nil) (defun nuke-trailing-whitespace-doit (&optional flag) (interactive) (let ((buffer-orig-read-only buffer-read-only) (buffer-read-only nil)) (save-excursion (save-restriction (save-match-data (widen) (goto-char (point-min)) (cond ((or (and (eq flag t) (not buffer-orig-read-only)) (interactive-p)) (while (re-search-forward nuke-trailing-whitespace-regexp (point-max) t) (delete-region (match-beginning 0) (match-end 0))) (goto-char (point-min)) (and (re-search-forward nuke-whitespace-eob-newline-regexp nil t) (delete-region (1+ (match-beginning 0)) (match-end 0)))) (t (query-replace-regexp nuke-trailing-whitespace-regexp "") (goto-char (point-min)) (and (re-search-forward nuke-whitespace-eob-newline-regexp nil t) (save-match-data (y-or-n-p "Delete excess trailing newlines at end of buffer? ")) (delete-region (1+ (match-beginning 0)) (match-end 0)))))))))) (defun nuke-whitespace-check-mode (&optional mode) (or mode (setq mode major-mode)) (cond ((memq mode nuke-trailing-whitespace-always-major-modes) t) ((memq mode nuke-trailing-whitespace-never-major-modes) nil) ;; Only query for visible buffers; invisible buffers are probably ;; managed by programs (e.g. w3 history list) and a query for them ;; is confusing. ((get-buffer-window (current-buffer) t) 'query) (t nil))) (provide 'nuke-whitespace) ;;; nuke-whitespace.el ends here.