;;; 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, 2012 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.
;;; 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:
;; 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)
(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
HCoop / bpt / emacs.git / blobdiff