X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/5df4f04cd32af723742c81095b38ae83b3c2b462..315865d31dde9f0771f96a98a4562bd282aa21ea:/lisp/electric.el diff --git a/lisp/electric.el b/lisp/electric.el index cac89b35b2..bf73dbb256 100644 --- a/lisp/electric.el +++ b/lisp/electric.el @@ -1,10 +1,10 @@ ;;; electric.el --- window maker and Command loop for `electric' modes -;; Copyright (C) 1985, 1986, 1995, 2001, 2002, 2003, 2004, -;; 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. +;; Copyright (C) 1985-1986, 1995, 2001-2014 Free Software Foundation, +;; Inc. ;; Author: K. Shane Hartman -;; Maintainer: FSF +;; Maintainer: emacs-devel@gnu.org ;; Keywords: extensions ;; This file is part of GNU Emacs. @@ -24,7 +24,18 @@ ;;; Commentary: -; zaaaaaaap +;; "Electric" has been used in Emacs to refer to different things. +;; Among them: +;; +;; - electric modes and buffers: modes that typically pop-up in a modal kind of +;; way a transient buffer that automatically disappears as soon as the user +;; is done with it. +;; +;; - electric keys: self inserting keys which additionally perform some side +;; operation which happens to be often convenient at that time. Examples of +;; such side operations are: reindenting code, inserting a newline, +;; ... auto-fill-mode and abbrev-mode can be considered as built-in forms of +;; electric key behavior. ;;; Code: @@ -51,30 +62,27 @@ ;; conditions for any error that occurred or nil if none. (defun Electric-command-loop (return-tag - &optional prompt inhibit-quit + &optional prompt inhibit-quitting loop-function loop-state) (let (cmd (err nil) + (inhibit-quit inhibit-quitting) (prompt-string prompt)) (while t - (if (not (or (stringp prompt) (eq prompt nil) (eq prompt 'noprompt))) + (if (functionp prompt) (setq prompt-string (funcall prompt))) (if (not (stringp prompt-string)) - (if (eq prompt-string 'noprompt) - (setq prompt-string nil) - (setq prompt-string "->"))) + (setq prompt-string (unless (eq prompt-string 'noprompt) "->"))) (setq cmd (read-key-sequence prompt-string)) (setq last-command-event (aref cmd (1- (length cmd))) this-command (key-binding cmd t) cmd this-command) - ;; This makes universal-argument-other-key work. - (setq universal-argument-num-events 0) (if (or (prog1 quit-flag (setq quit-flag nil)) (eq last-input-event ?\C-g)) (progn (setq unread-command-events nil prefix-arg nil) - ;; If it wasn't cancelling a prefix character, then quit. + ;; If it wasn't canceling a prefix character, then quit. (if (or (= (length (this-command-keys)) 1) (not inhibit-quit)) ; safety (progn (ding) @@ -159,7 +167,249 @@ (fit-window-to-buffer win max-height)) win))) +;;; Electric keys. + +(defgroup electricity () + "Electric behavior for self inserting keys." + :group 'editing) + +(defun electric--after-char-pos () + "Return the position after the char we just inserted. +Returns nil when we can't find this char." + (let ((pos (point))) + (when (or (eq (char-before) last-command-event) ;; Sanity check. + (save-excursion + (or (progn (skip-chars-backward " \t") + (setq pos (point)) + (eq (char-before) last-command-event)) + (progn (skip-chars-backward " \n\t") + (setq pos (point)) + (eq (char-before) last-command-event))))) + pos))) + +(defun electric--sort-post-self-insertion-hook () + "Ensure order of electric functions in `post-self-insertion-hook'. + +Hooks in this variable interact in non-trivial ways, so a +relative order must be maintained within it." + (setq-default post-self-insert-hook + (sort (default-value 'post-self-insert-hook) + #'(lambda (fn1 fn2) + (< (or (get fn1 'priority) 0) + (or (get fn2 'priority) 0)))))) + +;;; Electric indentation. + +;; Autoloading variables is generally undesirable, but major modes +;; should usually set this variable by adding elements to the default +;; value, which only works well if the variable is preloaded. +;;;###autoload +(defvar electric-indent-chars '(?\n) + "Characters that should cause automatic reindentation.") + +(defvar electric-indent-functions nil + "Special hook run to decide whether to auto-indent. +Each function is called with one argument (the inserted char), with +point right after that char, and it should return t to cause indentation, +`no-indent' to prevent indentation or nil to let other functions decide.") + +(defvar-local electric-indent-inhibit nil + "If non-nil, reindentation is not appropriate for this buffer. +This should be set by major modes such as `python-mode' since +Python does not lend itself to fully automatic indentation.") + +(defvar electric-indent-functions-without-reindent + '(indent-relative indent-to-left-margin indent-relative-maybe + py-indent-line coffee-indent-line org-indent-line yaml-indent-line + haskell-indentation-indent-line haskell-indent-cycle haskell-simple-indent + yaml-indent-line) + "List of indent functions that can't reindent. +If `line-indent-function' is one of those, then `electric-indent-mode' will +not try to reindent lines. It is normally better to make the major +mode set `electric-indent-inhibit', but this can be used as a workaround.") + +(defun electric-indent-post-self-insert-function () + "Function that `electric-indent-mode' adds to `post-self-insert-hook'. +This indents if the hook `electric-indent-functions' returns non-nil, +or if a member of `electric-indent-chars' was typed; but not in a string +or comment." + ;; FIXME: This reindents the current line, but what we really want instead is + ;; to reindent the whole affected text. That's the current line for simple + ;; cases, but not all cases. We do take care of the newline case in an + ;; ad-hoc fashion, but there are still missing cases such as the case of + ;; electric-pair-mode wrapping a region with a pair of parens. + ;; There might be a way to get it working by analyzing buffer-undo-list, but + ;; it looks challenging. + (let (pos) + (when (and + electric-indent-mode + ;; Don't reindent while inserting spaces at beginning of line. + (or (not (memq last-command-event '(?\s ?\t))) + (save-excursion (skip-chars-backward " \t") (not (bolp)))) + (setq pos (electric--after-char-pos)) + (save-excursion + (goto-char pos) + (let ((act (or (run-hook-with-args-until-success + 'electric-indent-functions + last-command-event) + (memq last-command-event electric-indent-chars)))) + (not + (or (memq act '(nil no-indent)) + ;; In a string or comment. + (unless (eq act 'do-indent) (nth 8 (syntax-ppss)))))))) + ;; For newline, we want to reindent both lines and basically behave like + ;; reindent-then-newline-and-indent (whose code we hence copied). + (let ((at-newline (<= pos (line-beginning-position)))) + (when at-newline + (let ((before (copy-marker (1- pos) t))) + (save-excursion + (unless (or (memq indent-line-function + electric-indent-functions-without-reindent) + electric-indent-inhibit) + ;; Don't reindent the previous line if the indentation function + ;; is not a real one. + (goto-char before) + (indent-according-to-mode)) + ;; We are at EOL before the call to indent-according-to-mode, and + ;; after it we usually are as well, but not always. We tried to + ;; address it with `save-excursion' but that uses a normal marker + ;; whereas we need `move after insertion', so we do the + ;; save/restore by hand. + (goto-char before) + (when (eolp) + ;; Remove the trailing whitespace after indentation because + ;; indentation may (re)introduce the whitespace. + (delete-horizontal-space t))))) + (unless (and electric-indent-inhibit + (not at-newline)) + (indent-according-to-mode)))))) + +(put 'electric-indent-post-self-insert-function 'priority 60) + +(defun electric-indent-just-newline (arg) + "Insert just a newline, without any auto-indentation." + (interactive "*P") + (let ((electric-indent-mode nil)) + (newline arg 'interactive))) + +;;;###autoload +(define-key global-map "\C-j" 'electric-newline-and-maybe-indent) +;;;###autoload +(defun electric-newline-and-maybe-indent () + "Insert a newline. +If `electric-indent-mode' is enabled, that's that, but if it +is *disabled* then additionally indent according to major mode. +Indentation is done using the value of `indent-line-function'. +In programming language modes, this is the same as TAB. +In some text modes, where TAB inserts a tab, this command indents to the +column specified by the function `current-left-margin'." + (interactive "*") + (if electric-indent-mode + (electric-indent-just-newline nil) + (newline-and-indent))) + +;;;###autoload +(define-minor-mode electric-indent-mode + "Toggle on-the-fly reindentation (Electric Indent mode). +With a prefix argument ARG, enable Electric Indent mode if ARG is +positive, and disable it otherwise. If called from Lisp, enable +the mode if ARG is omitted or nil. + +When enabled, this reindents whenever the hook `electric-indent-functions' +returns non-nil, or if you insert a character from `electric-indent-chars'. + +This is a global minor mode. To toggle the mode in a single buffer, +use `electric-indent-local-mode'." + :global t :group 'electricity + :initialize 'custom-initialize-delay + :init-value t + (if (not electric-indent-mode) + (unless (catch 'found + (dolist (buf (buffer-list)) + (with-current-buffer buf + (if electric-indent-mode (throw 'found t))))) + (remove-hook 'post-self-insert-hook + #'electric-indent-post-self-insert-function)) + (add-hook 'post-self-insert-hook + #'electric-indent-post-self-insert-function) + (electric--sort-post-self-insertion-hook))) + +;;;###autoload +(define-minor-mode electric-indent-local-mode + "Toggle `electric-indent-mode' only in this buffer." + :variable (buffer-local-value 'electric-indent-mode (current-buffer)) + (cond + ((eq electric-indent-mode (default-value 'electric-indent-mode)) + (kill-local-variable 'electric-indent-mode)) + ((not (default-value 'electric-indent-mode)) + ;; Locally enabled, but globally disabled. + (electric-indent-mode 1) ; Setup the hooks. + (setq-default electric-indent-mode nil) ; But keep it globally disabled. + ))) + +;;; Electric newlines after/before/around some chars. + +(defvar electric-layout-rules nil + "List of rules saying where to automatically insert newlines. + +Each rule has the form (CHAR . WHERE) where CHAR is the char that +was just inserted and WHERE specifies where to insert newlines +and can be: nil, `before', `after', `around', `after-stay', or a +function of no arguments that returns one of those symbols. + +The symbols specify where in relation to CHAR the newline +character(s) should be inserted. `after-stay' means insert a +newline after CHAR but stay in the same place.") + +(defun electric-layout-post-self-insert-function () + (let* ((rule (cdr (assq last-command-event electric-layout-rules))) + pos) + (when (and rule + (setq pos (electric--after-char-pos)) + ;; Not in a string or comment. + (not (nth 8 (save-excursion (syntax-ppss pos))))) + (let ((end (copy-marker (point))) + (sym (if (functionp rule) (funcall rule) rule))) + (set-marker-insertion-type end (not (eq sym 'after-stay))) + (goto-char pos) + (pcase sym + ;; FIXME: we used `newline' down here which called + ;; self-insert-command and ran post-self-insert-hook recursively. + ;; It happened to make electric-indent-mode work automatically with + ;; electric-layout-mode (at the cost of re-indenting lines + ;; multiple times), but I'm not sure it's what we want. + ;; + ;; FIXME: check eolp before inserting \n? + (`before (goto-char (1- pos)) (skip-chars-backward " \t") + (unless (bolp) (insert "\n"))) + (`after (insert "\n")) + (`after-stay (save-excursion + (let ((electric-layout-rules nil)) + (newline 1 t)))) + (`around (save-excursion + (goto-char (1- pos)) (skip-chars-backward " \t") + (unless (bolp) (insert "\n"))) + (insert "\n"))) ; FIXME: check eolp before inserting \n? + (goto-char end))))) + +(put 'electric-layout-post-self-insert-function 'priority 40) + +;;;###autoload +(define-minor-mode electric-layout-mode + "Automatically insert newlines around some chars. +With a prefix argument ARG, enable Electric Layout mode if ARG is +positive, and disable it otherwise. If called from Lisp, enable +the mode if ARG is omitted or nil. +The variable `electric-layout-rules' says when and how to insert newlines." + :global t :group 'electricity + (cond (electric-layout-mode + (add-hook 'post-self-insert-hook + #'electric-layout-post-self-insert-function) + (electric--sort-post-self-insertion-hook)) + (t + (remove-hook 'post-self-insert-hook + #'electric-layout-post-self-insert-function)))) + (provide 'electric) -;; arch-tag: dae045eb-dc2d-4fb7-9f27-9cc2ce277be8 ;;; electric.el ends here