* lisp/minibuffer.el: New file.

[bpt/emacs.git] / lisp / minibuffer.el

;;; minibuffer.el --- Minibuffer completion functions

;; Copyright (C) 2008  Free Software Foundation, Inc.

;; Author: Stefan Monnier <monnier@iro.umontreal.ca>

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; TODO:
;; - merge do-completion and complete-word
;; - move all I/O out of do-completion

;;; Code:

(eval-when-compile (require 'cl))

(defun minibuffer-message (message &rest args)
  "Temporarily display MESSAGE at the end of the minibuffer.
The text is displayed for `minibuffer-message-timeout' seconds,
or until the next input event arrives, whichever comes first.
Enclose MESSAGE in [...] if this is not yet the case.
If ARGS are provided, then pass MESSAGE through `format'."
  ;; Clear out any old echo-area message to make way for our new thing.
  (message nil)
  (unless (string-match "\\[.+\\]" message)
    (setq message (concat " [" message "]")))
  (when args (setq message (apply 'format message args)))
  (let ((ol (make-overlay (point-max) (point-max) nil t t)))
    (unwind-protect
        (progn
          (overlay-put ol 'after-string message)
          (sit-for (or minibuffer-message-timeout 1000000)))
      (delete-overlay ol))))

(defun minibuffer-completion-contents ()
  "Return the user input in a minibuffer before point as a string.
That is what completion commands operate on."
  (buffer-substring (field-beginning) (point)))

(defun delete-minibuffer-contents ()
  "Delete all user input in a minibuffer.
If the current buffer is not a minibuffer, erase its entire contents."
  (delete-field))

(defun minibuffer--maybe-completion-help ()
  (if completion-auto-help
      (minibuffer-completion-help)
    (minibuffer-message "Next char not unique")))

(defun minibuffer-do-completion ()
  "Do the completion and return a summary of what happened.
C = There were available completions.
E = After completion we now have an exact match.
M = Completion was performed, the text was Modified.

 CEM
 000 0 no possible completion
 010 1 was already an exact and unique completion
 110 3 was already an exact completion
 111 4 completed to an exact completion
 101 5 some completion happened
 100 6 no completion happened"
  (let* ((string (minibuffer-completion-contents))
         (completion (try-completion (field-string)
                                    minibuffer-completion-table
                                    minibuffer-completion-predicate)))
    (setq last-exact-completion nil)
    (cond
     ((null completion)
      (ding) (minibuffer-message "No match") 0)
     ((eq t completion) 1)              ;Exact and unique match.
     (t
      ;; `completed' should be t if some completion was done, which doesn't
      ;; include simply changing the case of the entered string.  However,
      ;; for appearance, the string is rewritten if the case changes.
      (let ((completed (not (eq t (compare-strings completion nil nil
                                                   string nil nil t))))
            (unchanged (eq t (compare-strings completion nil nil
                                              string nil nil nil))))
        (unless unchanged
          (let ((beg (field-beginning))
                (end (point)))
            (insert completion)
            (delete-region beg end)))
        (if (not (or unchanged completed))
	   ;; The case of the string changed, but that's all.  We're not sure
	   ;; whether this is a unique completion or not, so try again using
	   ;; the real case (this shouldn't recurse again, because the next
	   ;; time try-completion will return either t or the exact string).
           (minibuffer-do-completion)

          ;; It did find a match.  Do we match some possibility exactly now?
          (let ((exact (test-completion (field-string)
					minibuffer-completion-table
					minibuffer-completion-predicate)))
            (cond
             ((not exact)
              (if completed 5
                (minibuffer--maybe-completion-help)
                6))
             (completed 4)
             (t
              ;; If the last exact completion and this one were the same,
              ;; it means we've already given a "Complete but not unique"
              ;; message and the user's hit TAB again, so now we give him help.
              (if (eq this-command last-command)
                  (minibuffer-completion-help))
              3)))))))))

(defun minibuffer-complete ()
  "Complete the minibuffer contents as far as possible.
Return nil if there is no valid completion, else t.
If no characters can be completed, display a list of possible completions.
If you repeat this command after it displayed such a list,
scroll the window of possible completions."
  (interactive)
  ;; If the previous command was not this,
  ;; mark the completion buffer obsolete.
  (unless (eq this-command last-command)
    (setq minibuffer-scroll-window nil))

  (let ((window minibuffer-scroll-window))
    ;; If there's a fresh completion window with a live buffer,
    ;; and this command is repeated, scroll that window.
    (if (window-live-p window)
        (with-current-buffer (window-buffer window)
          (if (pos-visible-in-window-p (point-max) window)
	      ;; If end is in view, scroll up to the beginning.
	      (set-window-start window (point-min) nil)
	    ;; Else scroll down one screen.
	    (scroll-other-window))
	  nil)

      (let ((i (minibuffer-do-completion)))
        (case i
          (0 nil)
          (1 (goto-char (field-end))
             (minibuffer-message "Sole completion")
             t)
          (3 (goto-char (field-end))
             (minibuffer-message "Complete, but not unique")
             t)
          (t t))))))

(defun minibuffer-complete-and-exit ()
  "If the minibuffer contents is a valid completion then exit.
Otherwise try to complete it.  If completion leads to a valid completion,
a repetition of this command will exit."
  (interactive)
  (cond
   ;; Allow user to specify null string
   ((= (field-beginning) (field-end)) (exit-minibuffer))
   ((test-completion (field-string)
                     minibuffer-completion-table
                     minibuffer-completion-predicate)
    (when completion-ignore-case
      ;; Fixup case of the field, if necessary.
      (let* ((string (field-string))
	     (compl (try-completion string
				    minibuffer-completion-table
				    minibuffer-completion-predicate)))
	(when (and (stringp compl)
                   ;; If it weren't for this piece of paranoia, I'd replace
                   ;; the whole thing with a call to complete-do-completion.
                   (= (length string) (length compl)))
          (let ((beg (field-beginning))
                (end (field-end)))
            (goto-char end)
            (insert compl)
            (delete-region beg end)))))
    (exit-minibuffer))

   ((eq minibuffer-completion-confirm 'confirm-only)
    ;; The user is permitted to exit with an input that's rejected
    ;; by test-completion, but at the condition to confirm her choice.
    (if (eq last-command this-command)
	(exit-minibuffer)
      (minibuffer-message "Confirm")
      nil))

   (t
    ;; Call do-completion, but ignore errors.
    (let ((i (condition-case nil
                 (minibuffer-do-completion)
               (error 1))))
      (case i
        ((1 3) (exit-minibuffer))
        (4 (if (not minibuffer-completion-confirm)
               (exit-minibuffer)
             (minibuffer-message "Confirm")
             nil))
        (t nil))))))

(defun minibuffer-complete-word ()
  "Complete the minibuffer contents at most a single word.
After one word is completed as much as possible, a space or hyphen
is added, provided that matches some possible completion.
Return nil if there is no valid completion, else t."
  (interactive)
  (let* ((beg (field-beginning))
         (string (buffer-substring beg (point)))
         (completion (try-completion string
                                     minibuffer-completion-table
                                     minibuffer-completion-predicate)))
    (cond
     ((null completion)
      (ding) (minibuffer-message "No match") nil)
     ((eq t completion) nil)              ;Exact and unique match.
     (t
      ;; Completing a single word is actually more difficult than completing
      ;; as much as possible, because we first have to find the "current
      ;; position" in `completion' in order to find the end of the word
      ;; we're completing.  Normally, `string' is a prefix of `completion',
      ;; which makes it trivial to find the position, but with fancier
      ;; completion (plus env-var expansion, ...) `completion' might not
      ;; look anything like `string' at all.
      
      (when minibuffer-completing-file-name
	;; In order to minimize the problem mentioned above, let's try to
	;; reduce the different between `string' and `completion' by
	;; mirroring some of the work done in read-file-name-internal.
	(let ((substituted (condition-case nil
			       ;; Might fail when completing an env-var.
			       (substitute-in-file-name string)
			     (error string))))
	  (unless (eq string substituted)
	    (setq string substituted)
	    (let ((end (point)))
              (insert substituted)
              (delete-region beg end)))))

      ;; Make buffer (before point) contain the longest match
      ;; of `string's tail and `completion's head.
      (let* ((startpos (max 0 (- (length string) (length completion))))
             (length (- (length string) startpos)))
        (while (and (> length 0)
                    (not (eq t (compare-strings string startpos nil
                                                completion 0 length
                                                completion-ignore-case))))
          (setq startpos (1+ startpos))
          (setq length (1- length)))

        (setq string (substring string startpos))
        (delete-region beg (+ beg startpos)))

      ;; Now `string' is a prefix of `completion'.

      ;; If completion finds next char not unique,
      ;; consider adding a space or a hyphen.
      (when (= (length string) (length completion))
        (let ((exts '(" " "-"))
              tem)
          (while (and exts (not (stringp tem)))
            (setq tem (try-completion (concat string (pop exts))
                                      minibuffer-completion-table
                                      minibuffer-completion-predicate)))
          (if (stringp tem) (setq completion tem))))

      (if (= (length string) (length completion))
          ;; If got no characters, print help for user.
          (progn
            (if completion-auto-help (minibuffer-completion-help))
            nil)
        ;; Otherwise insert in minibuffer the chars we got.
        (if (string-match "\\W" completion (length string))
            ;; First find first word-break in the stuff found by completion.
            ;; i gets index in string of where to stop completing.
            (setq completion (substring completion 0 (match-end 0))))

        (if (and (eq ?/ (aref completion (1- (length completion))))
                 (eq ?/ (char-after)))
            (setq completion (substring completion 0 (1- (length completion)))))

        (let ((pos (point)))
          (insert completion)
          (delete-region beg pos)
          t))))))

(defun minibuffer-complete-insert-strings (strings)
  "Insert a list of STRINGS into the current buffer.
Uses columns to keep the listing readable but compact.
It also eliminates runs of equal strings."
  (when (consp strings)
    (let* ((length (apply 'max
			  (mapcar (lambda (s)
				    (if (consp s)
					(+ (length (car s)) (length (cadr s)))
				      (length s)))
				  strings)))
	   (window (get-buffer-window (current-buffer) 0))
	   (wwidth (if window (1- (window-width window)) 79))
	   (columns (min
		     ;; At least 2 columns; at least 2 spaces between columns.
		     (max 2 (/ wwidth (+ 2 length)))
		     ;; Don't allocate more columns than we can fill.
		     ;; Windows can't show less than 3 lines anyway.
		     (max 1 (/ (length strings) 2))))
	   (colwidth (/ wwidth columns))
           (column 0)
	   (laststring nil))
      ;; The insertion should be "sensible" no matter what choices were made
      ;; for the parameters above.
      (dolist (str strings)
	(unless (equal laststring str)  ; Remove (consecutive) duplicates.
	  (setq laststring str)
	  (unless (bolp)
            (insert " \t")
            (setq column (+ column colwidth))
            ;; Leave the space unpropertized so that in the case we're
            ;; already past the goal column, there is still
            ;; a space displayed.
            (set-text-properties (- (point) 1) (point)
                                 ;; We can't just set tab-width, because
                                 ;; completion-setup-function will kill all
                                 ;; local variables :-(
                                 `(display (space :align-to ,column))))
	  (when (< wwidth (+ (max colwidth
				  (if (consp str)
				      (+ (length (car str)) (length (cadr str)))
				    (length str)))
			     column))
	    (delete-char -2) (insert "\n") (setq column 0))
	  (if (not (consp str))
	      (put-text-property (point) (progn (insert str) (point))
				 'mouse-face 'highlight)
	    (put-text-property (point) (progn (insert (car str)) (point))
			       'mouse-face 'highlight)
	    (put-text-property (point) (progn (insert (cadr str)) (point))
                               'mouse-face nil)))))))

(defvar completion-common-substring)

(defun display-completion-list (completions &optional common-substring)
  "Display the list of completions, COMPLETIONS, using `standard-output'.
Each element may be just a symbol or string
or may be a list of two strings to be printed as if concatenated.
If it is a list of two strings, the first is the actual completion
alternative, the second serves as annotation.
`standard-output' must be a buffer.
The actual completion alternatives, as inserted, are given `mouse-face'
properties of `highlight'.
At the end, this runs the normal hook `completion-setup-hook'.
It can find the completion buffer in `standard-output'.
The optional second arg COMMON-SUBSTRING is a string.
It is used to put faces, `completions-first-difference' and
`completions-common-part' on the completion buffer. The
`completions-common-part' face is put on the common substring
specified by COMMON-SUBSTRING.  If COMMON-SUBSTRING is nil
and the current buffer is not the minibuffer, the faces are not put.
Internally, COMMON-SUBSTRING is bound to `completion-common-substring'
during running `completion-setup-hook'."
  (if (not (bufferp standard-output))
      ;; This *never* (ever) happens, so there's no point trying to be clever.
      (with-temp-buffer
	(let ((standard-output (current-buffer))
	      (completion-setup-hook nil))
	  (display-completion-list completions))
	(princ (buffer-string)))

    (with-current-buffer standard-output
      (goto-char (point-max))
      (if (null completions)
	  (insert "There are no possible completions of what you have typed.")
	
	(insert "Possible completions are:\n")
	(minibuffer-complete-insert-strings completions))))
  (let ((completion-common-substring common-substring))
    (run-hooks 'completion-setup-hook))
  nil)

(defun minibuffer-completion-help ()
  "Display a list of possible completions of the current minibuffer contents."
  (interactive)
  (message "Making completion list...")
  (let* ((string (field-string))
         (completions (all-completions
                       string
                       minibuffer-completion-table
                       minibuffer-completion-predicate
                       t)))
    (message nil)
    (if (and completions
             (or (cdr completions) (not (equal (car completions) string))))
        (with-output-to-temp-buffer "*Completions*"
          (display-completion-list (sort completions 'string-lessp)))

      ;; If there are no completions, or if the current input is already the
      ;; only possible completion, then hide (previous&stale) completions.
      (let ((window (and (get-buffer "*Completions*")
                         (get-buffer-window "*Completions*" 0))))
        (when (and (window-live-p window) (window-dedicated-p window))
          (condition-case ()
              (delete-window window)
            (error (iconify-frame (window-frame window))))))
      (ding)
      (minibuffer-message
       (if completions "Sole completion" "No completions")))
    nil))

(defun exit-minibuffer ()
  "Terminate this minibuffer argument."
  (interactive)
  ;; If the command that uses this has made modifications in the minibuffer,
  ;; we don't want them to cause deactivation of the mark in the original
  ;; buffer.
  ;; A better solution would be to make deactivate-mark buffer-local
  ;; (or to turn it into a list of buffers, ...), but in the mean time,
  ;; this should do the trick in most cases.
  (setq deactivate_mark nil)
  (throw 'exit nil))

(defun self-insert-and-exit ()
  "Terminate minibuffer input."
  (interactive)
  (if (characterp last-command-char)
      (call-interactively 'self-insert-command)
    (ding))
  (exit-minibuffer))

(provide 'minibuffer)
;;; minibuffer.el ends here