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

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;; Copyright (C) 2008, 2009  Free Software Foundation, Inc.
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;; Author: Stefan Monnier <monnier@iro.umontreal.ca>

;; This file is part of GNU Emacs.

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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; 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.

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;; GNU Emacs is distributed in the hope that it will be useful,
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;; 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
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;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
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;;; Commentary:

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;; Names with "--" are for functions and variables that are meant to be for
;; internal use only.

;; Functional completion tables have an extended calling conventions:
;; - The `action' can be (additionally to nil, t, and lambda) of the form
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;;   (boundaries . SUFFIX) in which case it should return
;;   (boundaries START . END).  See `completion-boundaries'.
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;;   Any other return value should be ignored (so we ignore values returned
;;   from completion tables that don't know about this new `action' form).

;;; Bugs:

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;; - completion-all-sorted-completions list all the completions, whereas
;;   it should only lists the ones that `try-completion' would consider.
;;   E.g.  it should honor completion-ignored-extensions.
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;; - choose-completion can't automatically figure out the boundaries
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;;   corresponding to the displayed completions because we only
;;   provide the start info but not the end info in
;;   completion-base-position.
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;; - quoting is problematic.  E.g. the double-dollar quoting used in
;;   substitie-in-file-name (and hence read-file-name-internal) bumps
;;   into various bugs:
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;; - choose-completion doesn't know how to quote the text it inserts.
;;   E.g. it fails to double the dollars in file-name completion, or
;;   to backslash-escape spaces and other chars in comint completion.
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;;   - when completing ~/tmp/fo$$o, the highligting in *Completions*
;;     is off by one position.
;;   - all code like PCM which relies on all-completions to match
;;     its argument gets confused because all-completions returns unquoted
;;     texts (as desired for *Completions* output).
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;; - C-x C-f ~/*/sr ? should not list "~/./src".
;; - minibuffer-force-complete completes ~/src/emacs/t<!>/lisp/minibuffer.el
;;   to ~/src/emacs/trunk/ and throws away lisp/minibuffer.el.
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;;; Todo:

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;; - make partial-complete-mode obsolete:
;;   - (?) <foo.h> style completion for file names.
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;;     This can't be done identically just by tweaking completion,
;;     because partial-completion-mode's behavior is to expand <string.h>
;;     to /usr/include/string.h only when exiting the minibuffer, at which
;;     point the completion code is actually not involved normally.
;;     Partial-completion-mode does it via a find-file-not-found-function.
;;   - special code for C-x C-f <> to visit the file ref'd at point
;;     via (require 'foo) or #include "foo".  ffap seems like a better
;;     place for this feature (supplemented with major-mode-provided
;;     functions to find the file ref'd at point).

;; - case-sensitivity currently confuses two issues:
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;;   - whether or not a particular completion table should be case-sensitive
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;;     (i.e. whether strings that differ only by case are semantically
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;;     equivalent)
;;   - whether the user wants completion to pay attention to case.
;;   e.g. we may want to make it possible for the user to say "first try
;;   completion case-sensitively, and if that fails, try to ignore case".

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;; - add support for ** to pcm.
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;; - Add vc-file-name-completion-table to read-file-name-internal.
;; - A feature like completing-help.el.
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;;; Code:

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

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;;; Completion table manipulation

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;; New completion-table operation.
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(defun completion-boundaries (string table pred suffix)
  "Return the boundaries of the completions returned by TABLE for STRING.
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STRING is the string on which completion will be performed.
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SUFFIX is the string after point.
The result is of the form (START . END) where START is the position
in STRING of the beginning of the completion field and END is the position
in SUFFIX of the end of the completion field.
E.g. for simple completion tables, the result is always (0 . (length SUFFIX))
and for file names the result is the positions delimited by
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the closest directory separators."
  (let ((boundaries (if (functionp table)
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                        (funcall table string pred (cons 'boundaries suffix)))))
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    (if (not (eq (car-safe boundaries) 'boundaries))
        (setq boundaries nil))
    (cons (or (cadr boundaries) 0)
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          (or (cddr boundaries) (length suffix)))))
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(defun completion--some (fun xs)
  "Apply FUN to each element of XS in turn.
Return the first non-nil returned value.
Like CL's `some'."
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  (let ((firsterror nil)
        res)
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    (while (and (not res) xs)
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      (condition-case err
          (setq res (funcall fun (pop xs)))
        (error (unless firsterror (setq firsterror err)) nil)))
    (or res
        (if firsterror (signal (car firsterror) (cdr firsterror))))))
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(defun complete-with-action (action table string pred)
  "Perform completion ACTION.
STRING is the string to complete.
TABLE is the completion table, which should not be a function.
PRED is a completion predicate.
ACTION can be one of nil, t or `lambda'."
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  (cond
   ((functionp table) (funcall table string pred action))
   ((eq (car-safe action) 'boundaries)
    (cons 'boundaries (completion-boundaries string table pred (cdr action))))
   (t
    (funcall
     (cond
      ((null action) 'try-completion)
      ((eq action t) 'all-completions)
      (t 'test-completion))
     string table pred))))
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(defun completion-table-dynamic (fun)
  "Use function FUN as a dynamic completion table.
FUN is called with one argument, the string for which completion is required,
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and it should return an alist containing all the intended possible completions.
This alist may be a full list of possible completions so that FUN can ignore
the value of its argument.  If completion is performed in the minibuffer,
FUN will be called in the buffer from which the minibuffer was entered.
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The result of the `completion-table-dynamic' form is a function
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that can be used as the COLLECTION argument to `try-completion' and
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`all-completions'.  See Info node `(elisp)Programmed Completion'."
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  (lexical-let ((fun fun))
    (lambda (string pred action)
      (with-current-buffer (let ((win (minibuffer-selected-window)))
                             (if (window-live-p win) (window-buffer win)
                               (current-buffer)))
        (complete-with-action action (funcall fun string) string pred)))))

(defmacro lazy-completion-table (var fun)
  "Initialize variable VAR as a lazy completion table.
If the completion table VAR is used for the first time (e.g., by passing VAR
as an argument to `try-completion'), the function FUN is called with no
arguments.  FUN must return the completion table that will be stored in VAR.
If completion is requested in the minibuffer, FUN will be called in the buffer
from which the minibuffer was entered.  The return value of
`lazy-completion-table' must be used to initialize the value of VAR.

You should give VAR a non-nil `risky-local-variable' property."
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  (declare (debug (symbolp lambda-expr)))
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  (let ((str (make-symbol "string")))
    `(completion-table-dynamic
      (lambda (,str)
        (when (functionp ,var)
          (setq ,var (,fun)))
        ,var))))

(defun completion-table-with-context (prefix table string pred action)
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  ;; TODO: add `suffix' maybe?
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  ;; Notice that `pred' may not be a function in some abusive cases.
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  (when (functionp pred)
    (setq pred
          (lexical-let ((pred pred))
            ;; Predicates are called differently depending on the nature of
            ;; the completion table :-(
            (cond
             ((vectorp table)           ;Obarray.
              (lambda (sym) (funcall pred (concat prefix (symbol-name sym)))))
             ((hash-table-p table)
              (lambda (s v) (funcall pred (concat prefix s))))
             ((functionp table)
              (lambda (s) (funcall pred (concat prefix s))))
             (t                         ;Lists and alists.
              (lambda (s)
                (funcall pred (concat prefix (if (consp s) (car s) s)))))))))
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  (if (eq (car-safe action) 'boundaries)
      (let* ((len (length prefix))
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             (bound (completion-boundaries string table pred (cdr action))))
        (list* 'boundaries (+ (car bound) len) (cdr bound)))
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    (let ((comp (complete-with-action action table string pred)))
      (cond
       ;; In case of try-completion, add the prefix.
       ((stringp comp) (concat prefix comp))
       (t comp)))))
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(defun completion-table-with-terminator (terminator table string pred action)
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  "Construct a completion table like TABLE but with an extra TERMINATOR.
This is meant to be called in a curried way by first passing TERMINATOR
and TABLE only (via `apply-partially').
TABLE is a completion table, and TERMINATOR is a string appended to TABLE's
completion if it is complete.  TERMINATOR is also used to determine the
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completion suffix's boundary.
TERMINATOR can also be a cons cell (TERMINATOR . TERMINATOR-REGEXP)
in which case TERMINATOR-REGEXP is a regular expression whose submatch
number 1 should match TERMINATOR.  This is used when there is a need to
distinguish occurrences of the TERMINATOR strings which are really terminators
from others (e.g. escaped)."
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  (cond
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   ((eq (car-safe action) 'boundaries)
    (let* ((suffix (cdr action))
           (bounds (completion-boundaries string table pred suffix))
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           (terminator-regexp (if (consp terminator)
                                  (cdr terminator) (regexp-quote terminator)))
           (max (string-match terminator-regexp suffix)))
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      (list* 'boundaries (car bounds)
             (min (cdr bounds) (or max (length suffix))))))
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   ((eq action nil)
    (let ((comp (try-completion string table pred)))
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      (if (consp terminator) (setq terminator (car terminator)))
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      (if (eq comp t)
          (concat string terminator)
        (if (and (stringp comp)
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                 ;; FIXME: Try to avoid this second call, especially since
                 ;; it may be very inefficient (because `comp' made us
                 ;; jump to a new boundary, so we complete in that
                 ;; boundary with an empty start string).
                 ;; completion-boundaries might help.
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                 (eq (try-completion comp table pred) t))
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            (concat comp terminator)
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          comp))))
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   ((eq action t)
    ;; FIXME: We generally want the `try' and `all' behaviors to be
    ;; consistent so pcm can merge the `all' output to get the `try' output,
    ;; but that sometimes clashes with the need for `all' output to look
    ;; good in *Completions*.
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    ;; (mapcar (lambda (s) (concat s terminator))
    ;;         (all-completions string table pred))))
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    (all-completions string table pred))
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   ;; completion-table-with-terminator is always used for
   ;; "sub-completions" so it's only called if the terminator is missing,
   ;; in which case `test-completion' should return nil.
   ((eq action 'lambda) nil)))

(defun completion-table-with-predicate (table pred1 strict string pred2 action)
  "Make a completion table equivalent to TABLE but filtered through PRED1.
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PRED1 is a function of one argument which returns non-nil if and only if the
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argument is an element of TABLE which should be considered for completion.
STRING, PRED2, and ACTION are the usual arguments to completion tables,
as described in `try-completion', `all-completions', and `test-completion'.
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If STRICT is t, the predicate always applies; if nil it only applies if
it does not reduce the set of possible completions to nothing.
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Note: TABLE needs to be a proper completion table which obeys predicates."
  (cond
   ((and (not strict) (eq action 'lambda))
    ;; Ignore pred1 since it doesn't really have to apply anyway.
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    (test-completion string table pred2))
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   (t
    (or (complete-with-action action table string
                              (if (null pred2) pred1
                                (lexical-let ((pred1 pred2) (pred2 pred2))
                                  (lambda (x)
                                    ;; Call `pred1' first, so that `pred2'
                                    ;; really can't tell that `x' is in table.
                                    (if (funcall pred1 x) (funcall pred2 x))))))
        ;; If completion failed and we're not applying pred1 strictly, try
        ;; again without pred1.
        (and (not strict)
             (complete-with-action action table string pred2))))))
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(defun completion-table-in-turn (&rest tables)
  "Create a completion table that tries each table in TABLES in turn."
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  ;; FIXME: the boundaries may come from TABLE1 even when the completion list
  ;; is returned by TABLE2 (because TABLE1 returned an empty list).
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  (lexical-let ((tables tables))
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    (lambda (string pred action)
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      (completion--some (lambda (table)
                          (complete-with-action action table string pred))
                        tables))))

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;; (defmacro complete-in-turn (a b) `(completion-table-in-turn ,a ,b))
;; (defmacro dynamic-completion-table (fun) `(completion-table-dynamic ,fun))
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(define-obsolete-function-alias
  'complete-in-turn 'completion-table-in-turn "23.1")
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(define-obsolete-function-alias
  'dynamic-completion-table 'completion-table-dynamic "23.1")
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;;; Minibuffer completion

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(defgroup minibuffer nil
  "Controlling the behavior of the minibuffer."
  :link '(custom-manual "(emacs)Minibuffer")
  :group 'environment)

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(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'."
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  (if (not (minibufferp (current-buffer)))
      (progn
        (if args
            (apply 'message message args)
          (message "%s" message))
        (prog1 (sit-for (or minibuffer-message-timeout 1000000))
          (message nil)))
    ;; Clear out any old echo-area message to make way for our new thing.
    (message nil)
    (setq message (if (and (null args) (string-match-p "\\` *\\[.+\\]\\'" message))
                      ;; Make sure we can put-text-property.
                      (copy-sequence message)
                    (concat " [" message "]")))
    (when args (setq message (apply 'format message args)))
    (let ((ol (make-overlay (point-max) (point-max) nil t t))
          ;; A quit during sit-for normally only interrupts the sit-for,
          ;; but since minibuffer-message is used at the end of a command,
          ;; at a time when the command has virtually finished already, a C-g
          ;; should really cause an abort-recursive-edit instead (i.e. as if
          ;; the C-g had been typed at top-level).  Binding inhibit-quit here
          ;; is an attempt to get that behavior.
          (inhibit-quit t))
      (unwind-protect
          (progn
            (unless (zerop (length message))
              ;; The current C cursor code doesn't know to use the overlay's
              ;; marker's stickiness to figure out whether to place the cursor
              ;; before or after the string, so let's spoon-feed it the pos.
              (put-text-property 0 1 'cursor t message))
            (overlay-put ol 'after-string message)
            (sit-for (or minibuffer-message-timeout 1000000)))
        (delete-overlay ol)))))
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(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."
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  ;; We used to do `delete-field' here, but when file name shadowing
  ;; is on, the field doesn't cover the entire minibuffer contents.
  (delete-region (minibuffer-prompt-end) (point-max)))
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(defcustom completion-auto-help t
  "Non-nil means automatically provide help for invalid completion input.
If the value is t the *Completion* buffer is displayed whenever completion
is requested but cannot be done.
If the value is `lazy', the *Completions* buffer is only displayed after
the second failed attempt to complete."
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  :type '(choice (const nil) (const t) (const lazy))
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  :group 'minibuffer)

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(defconst completion-styles-alist
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  '((emacs21
     completion-emacs21-try-completion completion-emacs21-all-completions
     "Simple prefix-based completion.")
    (emacs22
     completion-emacs22-try-completion completion-emacs22-all-completions
     "Prefix completion that only operates on the text before point.")
    (basic
     completion-basic-try-completion completion-basic-all-completions
     "Completion of the prefix before point and the suffix after point.")
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    (partial-completion
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     completion-pcm-try-completion completion-pcm-all-completions
     "Completion of multiple words, each one taken as a prefix.
E.g. M-x l-c-h can complete to list-command-history
and C-x C-f /u/m/s to /usr/monnier/src.")
    (initials
     completion-initials-try-completion completion-initials-all-completions
     "Completion of acronyms and initialisms.
E.g. can complete M-x lch to list-command-history
and C-x C-f ~/sew to ~/src/emacs/work."))
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  "List of available completion styles.
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Each element has the form (NAME TRY-COMPLETION ALL-COMPLETIONS DOC):
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where NAME is the name that should be used in `completion-styles',
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TRY-COMPLETION is the function that does the completion (it should
follow the same calling convention as `completion-try-completion'),
ALL-COMPLETIONS is the function that lists the completions (it should
follow the calling convention of `completion-all-completions'),
and DOC describes the way this style of completion works.")
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(defcustom completion-styles '(basic partial-completion emacs22)
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  "List of completion styles to use.
The available styles are listed in `completion-styles-alist'."
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  :type `(repeat (choice ,@(mapcar (lambda (x) (list 'const (car x)))
                                   completion-styles-alist)))
  :group 'minibuffer
  :version "23.1")

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(defun completion-try-completion (string table pred point)
  "Try to complete STRING using completion table TABLE.
Only the elements of table that satisfy predicate PRED are considered.
POINT is the position of point within STRING.
The return value can be either nil to indicate that there is no completion,
t to indicate that STRING is the only possible completion,
or a pair (STRING . NEWPOINT) of the completed result string together with
a new position for point."
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  (completion--some (lambda (style)
                      (funcall (nth 1 (assq style completion-styles-alist))
                               string table pred point))
                    completion-styles))
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(defun completion-all-completions (string table pred point)
  "List the possible completions of STRING in completion table TABLE.
Only the elements of table that satisfy predicate PRED are considered.
POINT is the position of point within STRING.
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The return value is a list of completions and may contain the base-size
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in the last `cdr'."
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  ;; FIXME: We need to additionally return completion-extra-size (similar
  ;; to completion-base-size but for the text after point).
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  (completion--some (lambda (style)
                      (funcall (nth 2 (assq style completion-styles-alist))
                               string table pred point))
                    completion-styles))
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(defun minibuffer--bitset (modified completions exact)
  (logior (if modified    4 0)
          (if completions 2 0)
          (if exact       1 0)))

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(defun completion--do-completion (&optional try-completion-function)
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  "Do the completion and return a summary of what happened.
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M = completion was performed, the text was Modified.
C = there were available Completions.
E = after completion we now have an Exact match.

 MCE
 000  0 no possible completion
 001  1 was already an exact and unique completion
 010  2 no completion happened
 011  3 was already an exact completion
 100  4 ??? impossible
 101  5 ??? impossible
 110  6 some completion happened
 111  7 completed to an exact completion"
  (let* ((beg (field-beginning))
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         (end (field-end))
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         (string (buffer-substring beg end))
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         (comp (funcall (or try-completion-function
			    'completion-try-completion)
			string
			minibuffer-completion-table
			minibuffer-completion-predicate
			(- (point) beg))))
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    (cond
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     ((null comp)
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      (minibuffer-hide-completions)
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      (ding) (minibuffer-message "No match") (minibuffer--bitset nil nil nil))
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     ((eq t comp)
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      (minibuffer-hide-completions)
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      (goto-char (field-end))
      (minibuffer--bitset nil nil t)) ;Exact and unique match.
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     (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.
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      (let* ((comp-pos (cdr comp))
	     (completion (car comp))
	     (completed (not (eq t (compare-strings completion nil nil
						    string nil nil t))))
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	     (unchanged (eq t (compare-strings completion nil nil
					       string nil nil nil))))
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        (unless unchanged
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          ;; Insert in minibuffer the chars we got.
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          (goto-char end)
          (insert completion)
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          (delete-region beg end))
	;; Move point.
	(goto-char (+ beg comp-pos))
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        (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).
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           (completion--do-completion try-completion-function)
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          ;; It did find a match.  Do we match some possibility exactly now?
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          (let ((exact (test-completion completion
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					minibuffer-completion-table
					minibuffer-completion-predicate)))
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            (if completed
                ;; We could also decide to refresh the completions,
                ;; if they're displayed (and assuming there are
                ;; completions left).
                (minibuffer-hide-completions)
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              ;; Show the completion table, if requested.
              (cond
               ((not exact)
                (if (case completion-auto-help
                      (lazy (eq this-command last-command))
                      (t completion-auto-help))
                    (minibuffer-completion-help)
                  (minibuffer-message "Next char not unique")))
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               ;; If the last exact completion and this one were the same, it
               ;; means we've already given a "Next char not unique" message
               ;; and the user's hit TAB again, so now we give him help.
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               ((eq this-command last-command)
                (if completion-auto-help (minibuffer-completion-help)))))

            (minibuffer--bitset completed t exact))))))))
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(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)

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      (case (completion--do-completion)
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        (#b000 nil)
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        (#b001 (minibuffer-message "Sole completion")
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               t)
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        (#b011 (minibuffer-message "Complete, but not unique")
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               t)
        (t     t)))))
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(defvar completion-all-sorted-completions nil)
(make-variable-buffer-local 'completion-all-sorted-completions)

(defun completion--flush-all-sorted-completions (&rest ignore)
  (setq completion-all-sorted-completions nil))

(defun completion-all-sorted-completions ()
  (or completion-all-sorted-completions
      (let* ((start (field-beginning))
             (end (field-end))
             (all (completion-all-completions (buffer-substring start end)
                                              minibuffer-completion-table
                                              minibuffer-completion-predicate
                                              (- (point) start)))
             (last (last all))
             (base-size (or (cdr last) 0)))
        (when last
          (setcdr last nil)
          ;; Prefer shorter completions.
          (setq all (sort all (lambda (c1 c2) (< (length c1) (length c2)))))
          ;; Prefer recently used completions.
          (let ((hist (symbol-value minibuffer-history-variable)))
            (setq all (sort all (lambda (c1 c2)
                                  (> (length (member c1 hist))
                                     (length (member c2 hist)))))))
          ;; Cache the result.  This is not just for speed, but also so that
          ;; repeated calls to minibuffer-force-complete can cycle through
          ;; all possibilities.
          (add-hook 'after-change-functions
                    'completion--flush-all-sorted-completions nil t)
          (setq completion-all-sorted-completions
                (nconc all base-size))))))

(defun minibuffer-force-complete ()
  "Complete the minibuffer to an exact match.
Repeated uses step through the possible completions."
  (interactive)
  ;; FIXME: Need to deal with the extra-size issue here as well.
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  ;; FIXME: ~/src/emacs/t<M-TAB>/lisp/minibuffer.el completes to
  ;; ~/src/emacs/trunk/ and throws away lisp/minibuffer.el.
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  (let* ((start (field-beginning))
         (end (field-end))
         (all (completion-all-sorted-completions)))
    (if (not (consp all))
        (minibuffer-message (if all "No more completions" "No completions"))
      (goto-char end)
      (insert (car all))
      (delete-region (+ start (cdr (last all))) end)
      ;; If completing file names, (car all) may be a directory, so we'd now
      ;; have a new set of possible completions and might want to reset
      ;; completion-all-sorted-completions to nil, but we prefer not to,
      ;; so that repeated calls minibuffer-force-complete still cycle
      ;; through the previous possible completions.
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      (let ((last (last all)))
        (setcdr last (cons (car all) (cdr last)))
        (setq completion-all-sorted-completions (cdr all))))))
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601
(defvar minibuffer-confirm-exit-commands
602
  '(minibuffer-complete minibuffer-complete-word PC-complete PC-complete-word)
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  "A list of commands which cause an immediately following
`minibuffer-complete-and-exit' to ask for extra confirmation.")

606
(defun minibuffer-complete-and-exit ()
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  "Exit if the minibuffer contains a valid completion.
Otherwise, try to complete the minibuffer contents.  If
completion leads to a valid completion, a repetition of this
command will exit.

If `minibuffer-completion-confirm' is `confirm', do not try to
 complete; instead, ask for confirmation and accept any input if
 confirmed.
If `minibuffer-completion-confirm' is `confirm-after-completion',
 do not try to complete; instead, ask for confirmation if the
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 preceding minibuffer command was a member of
 `minibuffer-confirm-exit-commands', and accept the input
 otherwise."
620
  (interactive)
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  (let ((beg (field-beginning))
        (end (field-end)))
    (cond
     ;; Allow user to specify null string
     ((= beg end) (exit-minibuffer))
     ((test-completion (buffer-substring beg end)
                       minibuffer-completion-table
                       minibuffer-completion-predicate)
      (when completion-ignore-case
        ;; Fixup case of the field, if necessary.
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        (let* ((string (buffer-substring beg end))
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               (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 do-completion.
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                     ;; This is important, e.g. when the current minibuffer's
                     ;; content is a directory which only contains a single
                     ;; file, so `try-completion' actually completes to
                     ;; that file.
643
                     (= (length string) (length compl)))
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            (goto-char end)
            (insert compl)
646 647
            (delete-region beg end))))
      (exit-minibuffer))
648

649
     ((eq minibuffer-completion-confirm 'confirm)
650
      ;; The user is permitted to exit with an input that's rejected
651
      ;; by test-completion, after confirming her choice.
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      (if (eq last-command this-command)
          (exit-minibuffer)
        (minibuffer-message "Confirm")
        nil))
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     ((eq minibuffer-completion-confirm 'confirm-after-completion)
      ;; Similar to the above, but only if trying to exit immediately
      ;; after typing TAB (this catches most minibuffer typos).
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      (if (memq last-command minibuffer-confirm-exit-commands)
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	  (progn (minibuffer-message "Confirm")
		 nil)
	(exit-minibuffer)))

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     (t
      ;; Call do-completion, but ignore errors.
      (case (condition-case nil
                (completion--do-completion)
              (error 1))
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        ((#b001 #b011) (exit-minibuffer))
        (#b111 (if (not minibuffer-completion-confirm)
                   (exit-minibuffer)
                 (minibuffer-message "Confirm")
                 nil))
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        (t nil))))))

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(defun completion--try-word-completion (string table predicate point)
  (let ((comp (completion-try-completion string table predicate point)))
    (if (not (consp comp))
        comp
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682 683
      ;; If completion finds next char not unique,
      ;; consider adding a space or a hyphen.
684
      (when (= (length string) (length (car comp)))
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        ;; Mark the added char with the `completion-word' property, so it
        ;; can be handled specially by completion styles such as
        ;; partial-completion.
        ;; We used to remove `partial-completion' from completion-styles
        ;; instead, but it was too blunt, leading to situations where SPC
        ;; was the only insertable char at point but minibuffer-complete-word
        ;; refused inserting it.
        (let ((exts (mapcar (lambda (str) (propertize str 'completion-try-word t))
                            '(" " "-")))
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              (before (substring string 0 point))
              (after (substring string point))
	      tem)
	  (while (and exts (not (consp tem)))
698
            (setq tem (completion-try-completion
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		       (concat before (pop exts) after)
		       table predicate (1+ point))))
	  (if (consp tem) (setq comp tem))))
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      ;; 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.
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      (let* ((comppoint (cdr comp))
	     (completion (car comp))
	     (before (substring string 0 point))
	     (combined (concat before "\n" completion)))
        ;; Find in completion the longest text that was right before point.
        (when (string-match "\\(.+\\)\n.*?\\1" combined)
          (let* ((prefix (match-string 1 before))
                 ;; We used non-greedy match to make `rem' as long as possible.
                 (rem (substring combined (match-end 0)))
                 ;; Find in the remainder of completion the longest text
                 ;; that was right after point.
                 (after (substring string point))
                 (suffix (if (string-match "\\`\\(.+\\).*\n.*\\1"
                                           (concat after "\n" rem))
                             (match-string 1 after))))
            ;; The general idea is to try and guess what text was inserted
            ;; at point by the completion.  Problem is: if we guess wrong,
            ;; we may end up treating as "added by completion" text that was
            ;; actually painfully typed by the user.  So if we then cut
            ;; after the first word, we may throw away things the
            ;; user wrote.  So let's try to be as conservative as possible:
            ;; only cut after the first word, if we're reasonably sure that
            ;; our guess is correct.
            ;; Note: a quick survey on emacs-devel seemed to indicate that
            ;; nobody actually cares about the "word-at-a-time" feature of
            ;; minibuffer-complete-word, whose real raison-d'être is that it
            ;; tries to add "-" or " ".  One more reason to only cut after
            ;; the first word, if we're really sure we're right.
            (when (and (or suffix (zerop (length after)))
                       (string-match (concat
                                      ;; Make submatch 1 as small as possible
                                      ;; to reduce the risk of cutting
                                      ;; valuable text.
                                      ".*" (regexp-quote prefix) "\\(.*?\\)"
                                      (if suffix (regexp-quote suffix) "\\'"))
                                     completion)
                       ;; The new point in `completion' should also be just
                       ;; before the suffix, otherwise something more complex
                       ;; is going on, and we're not sure where we are.
                       (eq (match-end 1) comppoint)
                       ;; (match-beginning 1)..comppoint is now the stretch
                       ;; of text in `completion' that was completed at point.
		       (string-match "\\W" completion (match-beginning 1))
		       ;; Is there really something to cut?
		       (> comppoint (match-end 0)))
              ;; Cut after the first word.
              (let ((cutpos (match-end 0)))
                (setq completion (concat (substring completion 0 cutpos)
                                         (substring completion comppoint)))
                (setq comppoint cutpos)))))

	(cons completion comppoint)))))
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(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)
770
  (case (completion--do-completion 'completion--try-word-completion)
771
    (#b000 nil)
772
    (#b001 (minibuffer-message "Sole completion")
773
           t)
774
    (#b011 (minibuffer-message "Complete, but not unique")
775 776
           t)
    (t     t)))
777

778 779 780
(defface completions-annotations '((t :inherit italic))
  "Face to use for annotations in the *Completions* buffer.")

781
(defun completion--insert-strings (strings)
782 783 784 785 786 787 788
  "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)
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					(+ (string-width (car s))
                                           (string-width (cadr s)))
				      (string-width s)))
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				  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)
807
	(unless (equal laststring str) ; Remove (consecutive) duplicates.
808
	  (setq laststring str)
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          (let ((length (if (consp str)
                            (+ (string-width (car str))
                               (string-width (cadr str)))
                          (string-width str))))
            (unless (bolp)
              (if (< wwidth (+ (max colwidth length) column))
                  ;; No space for `str' at point, move to next line.
                  (progn (insert "\n") (setq column 0))
                (insert " \t")
                ;; 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)))
                nil))
            (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)
832 833 834
              (add-text-properties (point) (progn (insert (cadr str)) (point))
                                   '(mouse-face nil
                                     face completions-annotations)))
835 836 837 838
            ;; Next column to align to.
            (setq column (+ column
                            ;; Round up to a whole number of columns.
                            (* colwidth (ceiling length colwidth))))))))))
839

840 841
(defvar completion-common-substring nil)
(make-obsolete-variable 'completion-common-substring nil "23.1")
842

843 844 845 846 847
(defvar completion-setup-hook nil
  "Normal hook run at the end of setting up a completion list buffer.
When this hook is run, the current buffer is the one in which the
command to display the completion list buffer was run.
The completion list buffer is available as the value of `standard-output'.
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See also `display-completion-list'.")

(defface completions-first-difference
  '((t (:inherit bold)))
  "Face put on the first uncommon character in completions in *Completions* buffer."
  :group 'completion)

(defface completions-common-part
  '((t (:inherit default)))
  "Face put on the common prefix substring in completions in *Completions* buffer.
The idea of `completions-common-part' is that you can use it to
make the common parts less visible than normal, so that the rest
of the differing parts is, by contrast, slightly highlighted."
  :group 'completion)

863
(defun completion-hilit-commonality (completions prefix-len base-size)
864
  (when completions
865
    (let ((com-str-len (- prefix-len (or base-size 0))))
866 867
      (nconc
       (mapcar
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        (lambda (elem)
          (let ((str
                 ;; Don't modify the string itself, but a copy, since the
                 ;; the string may be read-only or used for other purposes.
                 ;; Furthermore, since `completions' may come from
                 ;; display-completion-list, `elem' may be a list.
                 (if (consp elem)
                     (car (setq elem (cons (copy-sequence (car elem))
                                           (cdr elem))))
                   (setq elem (copy-sequence elem)))))
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            (put-text-property 0
			       ;; If completion-boundaries returns incorrect
			       ;; values, all-completions may return strings
			       ;; that don't contain the prefix.
			       (min com-str-len (length str))
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                               'font-lock-face 'completions-common-part
                               str)
            (if (> (length str) com-str-len)
                (put-text-property com-str-len (1+ com-str-len)
                                   'font-lock-face 'completions-first-difference
                                   str)))
          elem)
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        completions)
       base-size))))
892

893
(defun display-completion-list (completions &optional common-substring)
894 895 896 897 898 899 900 901 902 903
  "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'.
904

905
The obsolete optional arg COMMON-SUBSTRING, if non-nil, should be a string
906 907
specifying a common substring for adding the faces
`completions-first-difference' and `completions-common-part' to
908
the completions buffer."
909 910
  (if common-substring
      (setq completions (completion-hilit-commonality
911 912 913
                         completions (length common-substring)
                         ;; We don't know the base-size.
                         nil)))
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  (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))
919
	  (display-completion-list completions common-substring))
920 921
	(princ (buffer-string)))

922 923 924 925 926 927
    (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")
        (completion--insert-strings completions))))
928

929 930
  ;; The hilit used to be applied via completion-setup-hook, so there
  ;; may still be some code that uses completion-common-substring.
931 932 933
  (with-no-warnings
    (let ((completion-common-substring common-substring))
      (run-hooks 'completion-setup-hook)))
934 935
  nil)

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(defvar completion-annotate-function
  nil
  ;; Note: there's a lot of scope as for when to add annotations and
  ;; what annotations to add.  E.g. completing-help.el allowed adding
  ;; the first line of docstrings to M-x completion.  But there's
  ;; a tension, since such annotations, while useful at times, can
  ;; actually drown the useful information.
  ;; So completion-annotate-function should be used parsimoniously, or
  ;; else only used upon a user's request (e.g. we could add a command
  ;; to completion-list-mode to add annotations to the current
  ;; completions).
  "Function to add annotations in the *Completions* buffer.
The function takes a completion and should either return nil, or a string that
will be displayed next to the completion.  The function can access the
completion table and predicates via `minibuffer-completion-table' and related
variables.")

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(defun minibuffer-completion-help ()
  "Display a list of possible completions of the current minibuffer contents."
  (interactive)
  (message "Making completion list...")
957 958
  (let* ((start (field-beginning))
         (string (field-string))
959
         (completions (completion-all-completions
960 961
                       string
                       minibuffer-completion-table
962 963
                       minibuffer-completion-predicate
                       (- (point) (field-beginning)))))
964 965
    (message nil)
    (if (and completions
966 967
             (or (consp (cdr completions))
                 (not (equal (car completions) string))))
968
        (with-output-to-temp-buffer "*Completions*"
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          (let* ((last (last completions))
                 (base-size (cdr last)))
            ;; Remove the base-size tail because `sort' requires a properly
            ;; nil-terminated list.
            (when last (setcdr last nil))
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            (setq completions (sort completions 'string-lessp))
            (when completion-annotate-function
              (setq completions
                    (mapcar (lambda (s)
                              (let ((ann
                                     (funcall completion-annotate-function s)))
                                (if ann (list s ann) s)))
                            completions)))
982 983 984 985 986 987 988
            (with-current-buffer standard-output
	      (set (make-local-variable 'completion-base-position)
		   ;; FIXME: We should provide the END part as well, but
		   ;; currently completion-all-completions does not give
		   ;; us the necessary information.
		   (list (+ start base-size) nil)))
            (display-completion-list completions)))
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      ;; If there are no completions, or if the current input is already the
      ;; only possible completion, then hide (previous&stale) completions.
992
      (minibuffer-hide-completions)
993 994 995 996 997
      (ding)
      (minibuffer-message
       (if completions "Sole completion" "No completions")))
    nil))

998 999 1000 1001 1002 1003 1004
(defun minibuffer-hide-completions ()
  "Get rid of an out-of-date *Completions* buffer."
  ;; FIXME: We could/should use minibuffer-scroll-window here, but it
  ;; can also point to the minibuffer-parent-window, so it's a bit tricky.
  (let ((win (get-buffer-window "*Completions*" 0)))
    (if win (with-selected-window win (bury-buffer)))))

1005 1006 1007 1008 1009 1010 1011 1012 1013
(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.
1014
  (setq deactivate-mark nil)
1015 1016 1017 1018 1019
  (throw 'exit nil))

(defun self-insert-and-exit ()
  "Terminate minibuffer input."
  (interactive)
1020
  (if (characterp last-command-event)
1021 1022 1023 1024
      (call-interactively 'self-insert-command)
    (ding))
  (exit-minibuffer))

1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051
(defvar completion-in-region-functions nil
  "Wrapper hook around `complete-in-region'.
The functions on this special hook are called with 5 arguments:
  NEXT-FUN START END COLLECTION PREDICATE.
NEXT-FUN is a function of four arguments (START END COLLECTION PREDICATE)
that performs the default operation.  The other four argument are like
the ones passed to `complete-in-region'.  The functions on this hook
are expected to perform completion on START..END using COLLECTION
and PREDICATE, either by calling NEXT-FUN or by doing it themselves.")

(defun completion-in-region (start end collection &optional predicate)
  "Complete the text between START and END using COLLECTION.
Point needs to be somewhere between START and END."
  ;; FIXME: some callers need to setup completion-ignore-case,
  ;; completion-ignored-extensions.  The latter can be embedded in the
  ;; completion tables, but the first cannot (actually, maybe it should).
  (assert (<= start (point)) (<= (point) end))
  ;; FIXME: undisplay the *Completions* buffer once the completion is done.
  (with-wrapper-hook
      completion-in-region-functions (start end collection predicate)
    (let ((minibuffer-completion-table collection)
          (minibuffer-completion-predicate predicate)
          (ol (make-overlay start end nil nil t)))
      (overlay-put ol 'field 'completion)
      (unwind-protect
          (call-interactively 'minibuffer-complete)
        (delete-overlay ol)))))
1052

1053 1054 1055 1056 1057 1058 1059
(let ((map minibuffer-local-map))
  (define-key map "\C-g" 'abort-recursive-edit)
  (define-key map "\r" 'exit-minibuffer)
  (define-key map "\n" 'exit-minibuffer))

(let ((map minibuffer-local-completion-map))
  (define-key map "\t" 'minibuffer-complete)
1060 1061 1062
  ;; M-TAB is already abused for many other purposes, so we should find
  ;; another binding for it.
  ;; (define-key map "\e\t" 'minibuffer-force-complete)
1063 1064 1065 1066 1067 1068 1069 1070 1071
  (define-key map " " 'minibuffer-complete-word)
  (define-key map "?" 'minibuffer-completion-help))

(let ((map minibuffer-local-must-match-map))
  (define-key map "\r" 'minibuffer-complete-and-exit)
  (define-key map "\n" 'minibuffer-complete-and-exit))

(let ((map minibuffer-local-filename-completion-map))
  (define-key map " " nil))
1072
(let ((map minibuffer-local-filename-must-match-map))
1073 1074 1075 1076 1077 1078 1079 1080 1081
  (define-key map " " nil))

(let ((map minibuffer-local-ns-map))
  (define-key map " " 'exit-minibuffer)
  (define-key map "\t" 'exit-minibuffer)
  (define-key map "?" 'self-insert-and-exit))

;;; Completion tables.

1082 1083 1084
(defun minibuffer--double-dollars (str)
  (replace-regexp-in-string "\\$" "$$" str))

1085 1086
(defun completion--make-envvar-table ()
  (mapcar (lambda (enventry)
1087
            (substring enventry 0 (string-match-p "=" enventry)))
1088 1089
          process-environment))

1090 1091 1092 1093
(defconst completion--embedded-envvar-re
  (concat "\\(?:^\\|[^$]\\(?:\\$\\$\\)*\\)"
          "$\\([[:alnum:]_]*\\|{\\([^}]*\\)\\)\\'"))

1094
(defun completion--embedded-envvar-table (string pred action)
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  "Completion table for envvars embedded in a string.
The envvar syntax (and escaping) rules followed by this table are the
same as `substitute-in-file-name'."
  ;; We ignore `pred', because the predicates passed to us via
  ;; read-file-name-internal are not 100% correct and fail here:
  ;; e.g. we get predicates like file-directory-p there, whereas the filename
  ;; completed needs to be passed through substitute-in-file-name before it
  ;; can be passed to file-directory-p.
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  (when (string-match completion--embedded-envvar-re string)
    (let* ((beg (or (match-beginning 2) (match-beginning 1)))
           (table (completion--make-envvar-table))
           (prefix (substring string 0 beg)))
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      (cond
       ((eq action 'lambda)
        ;; This table is expected to be used in conjunction with some
        ;; other table that provides the "main" completion.  Let the
        ;; other table handle the test-completion case.
        nil)
       ((eq (car-safe action) 'boundaries)
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          ;; Only return boundaries if there's something to complete,
          ;; since otherwise when we're used in
          ;; completion-table-in-turn, we could return boundaries and
          ;; let some subsequent table return a list of completions.
          ;; FIXME: Maybe it should rather be fixed in
          ;; completion-table-in-turn instead, but it's difficult to
          ;; do it efficiently there.
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        (when (try-completion (substring string beg) table nil)
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            ;; Compute the boundaries of the subfield to which this
            ;; completion applies.
            (let ((suffix (cdr action)))
              (list* 'boundaries
                     (or (match-beginning 2) (match-beginning 1))
                     (when (string-match "[^[:alnum:]_]" suffix)
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                     (match-beginning 0))))))
       (t
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        (if (eq (aref string (1- beg)) ?{)
            (setq table (apply-partially 'completion-table-with-terminator
                                         "}" table)))
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        ;; Even if file-name completion is case-insensitive, we want
        ;; envvar completion to be case-sensitive.
        (let ((completion-ignore-case nil))
          (completion-table-with-context