lisp/battery.el

   1 ;;; battery.el --- display battery status information  -*- coding: iso-8859-1 -*-
   2
   3 ;; Copyright (C) 1997, 1998, 2000, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   5
   6 ;; Author: Ralph Schleicher <rs@nunatak.allgaeu.org>
   7 ;; Keywords: hardware
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; There is at present support for GNU/Linux, OS X and Windows.  This
  27 ;; library supports both the `/proc/apm' file format of Linux version
  28 ;; 1.3.58 or newer and the `/proc/acpi/' directory structure of Linux
  29 ;; 2.4.20 and 2.6.  Darwin (OS X) is supported by using the `pmset'
  30 ;; program.  Windows is supported by the GetSystemPowerStatus API call.
  31
  32 ;;; Code:
  33
  34 (require 'timer)
  35 (eval-when-compile (require 'cl))
  36
  37 \f
  38 (defgroup battery nil
  39   "Display battery status information."
  40   :prefix "battery-"
  41   :group 'hardware)
  42
  43 (defcustom battery-status-function
  44   (cond ((and (eq system-type 'gnu/linux)
  45               (file-readable-p "/proc/apm"))
  46          'battery-linux-proc-apm)
  47         ((and (eq system-type 'gnu/linux)
  48               (file-directory-p "/proc/acpi/battery"))
  49          'battery-linux-proc-acpi)
  50         ((and (eq system-type 'gnu/linux)
  51               (file-directory-p "/sys/class/power_supply/")
  52               (directory-files "/sys/class/power_supply/" nil "BAT[0-9]$"))
  53          'battery-linux-sysfs)
  54         ((and (eq system-type 'darwin)
  55               (condition-case nil
  56                   (with-temp-buffer
  57                     (and (eq (call-process "pmset" nil t nil "-g" "ps") 0)
  58                          (> (buffer-size) 0)))
  59                 (error nil)))
  60          'battery-pmset)
  61         ((eq system-type 'windows-nt)
  62          'w32-battery-status))
  63   "Function for getting battery status information.
  64 The function has to return an alist of conversion definitions.
  65 Its cons cells are of the form
  66
  67     (CONVERSION . REPLACEMENT-TEXT)
  68
  69 CONVERSION is the character code of a \"conversion specification\"
  70 introduced by a `%' character in a control string."
  71   :type '(choice (const nil) function)
  72   :group 'battery)
  73
  74 (defcustom battery-echo-area-format
  75   (cond ((eq battery-status-function 'battery-linux-proc-acpi)
  76          "Power %L, battery %B at %r (%p%% load, remaining time %t)")
  77         ((eq battery-status-function 'battery-linux-sysfs)
  78          "Power %L, battery %B (%p%% load)")
  79         ((eq battery-status-function 'battery-pmset)
  80          "%L power, battery %B (%p%% load, remaining time %t)")
  81         (battery-status-function
  82          "Power %L, battery %B (%p%% load, remaining time %t)"))
  83   "Control string formatting the string to display in the echo area.
  84 Ordinary characters in the control string are printed as-is, while
  85 conversion specifications introduced by a `%' character in the control
  86 string are substituted as defined by the current value of the variable
  87 `battery-status-function'.  Here are the ones generally available:
  88 %c Current capacity (mAh or mWh)
  89 %r Current rate of charge or discharge
  90 %B Battery status (verbose)
  91 %b Battery status: empty means high, `-' means low,
  92    `!' means critical, and `+' means charging
  93 %d Temperature (in degrees Celsius)
  94 %L AC line status (verbose)
  95 %p Battery load percentage
  96 %m Remaining time (to charge or discharge) in minutes
  97 %h Remaining time (to charge or discharge) in hours
  98 %t Remaining time (to charge or discharge) in the form `h:min'"
  99   :type '(choice string (const nil))
 100   :group 'battery)
 101
 102 (defvar battery-mode-line-string nil
 103   "String to display in the mode line.")
 104 ;;;###autoload (put 'battery-mode-line-string 'risky-local-variable t)
 105
 106 (defcustom battery-mode-line-format
 107   (cond ((eq battery-status-function 'battery-linux-proc-acpi)
 108          "[%b%p%%,%d°C]")
 109         (battery-status-function
 110          "[%b%p%%]"))
 111   "Control string formatting the string to display in the mode line.
 112 Ordinary characters in the control string are printed as-is, while
 113 conversion specifications introduced by a `%' character in the control
 114 string are substituted as defined by the current value of the variable
 115 `battery-status-function'.  Here are the ones generally available:
 116 %c Current capacity (mAh or mWh)
 117 %r Current rate of charge or discharge
 118 %B Battery status (verbose)
 119 %b Battery status: empty means high, `-' means low,
 120    `!' means critical, and `+' means charging
 121 %d Temperature (in degrees Celsius)
 122 %L AC line status (verbose)
 123 %p Battery load percentage
 124 %m Remaining time (to charge or discharge) in minutes
 125 %h Remaining time (to charge or discharge) in hours
 126 %t Remaining time (to charge or discharge) in the form `h:min'"
 127   :type '(choice string (const nil))
 128   :group 'battery)
 129
 130 (defcustom battery-update-interval 60
 131   "Seconds after which the battery status will be updated."
 132   :type 'integer
 133   :group 'battery)
 134
 135 (defcustom battery-load-low 25
 136   "Upper bound of low battery load percentage.
 137 A battery load percentage below this number is considered low."
 138   :type 'integer
 139   :group 'battery)
 140
 141 (defcustom battery-load-critical 10
 142   "Upper bound of critical battery load percentage.
 143 A battery load percentage below this number is considered critical."
 144   :type 'integer
 145   :group 'battery)
 146
 147 (defvar battery-update-timer nil
 148   "Interval timer object.")
 149
 150 ;;;###autoload
 151 (defun battery ()
 152   "Display battery status information in the echo area.
 153 The text being displayed in the echo area is controlled by the variables
 154 `battery-echo-area-format' and `battery-status-function'."
 155   (interactive)
 156   (message "%s" (if (and battery-echo-area-format battery-status-function)
 157                     (battery-format battery-echo-area-format
 158                                     (funcall battery-status-function))
 159                   "Battery status not available")))
 160
 161 ;;;###autoload
 162 (define-minor-mode display-battery-mode
 163   "Display battery status information in the mode line.
 164 The text being displayed in the mode line is controlled by the variables
 165 `battery-mode-line-format' and `battery-status-function'.
 166 The mode line will be updated automatically every `battery-update-interval'
 167 seconds."
 168   :global t :group 'battery
 169   (setq battery-mode-line-string "")
 170   (or global-mode-string (setq global-mode-string '("")))
 171   (and battery-update-timer (cancel-timer battery-update-timer))
 172   (if (not display-battery-mode)
 173       (setq global-mode-string
 174             (delq 'battery-mode-line-string global-mode-string))
 175     (add-to-list 'global-mode-string 'battery-mode-line-string t)
 176     (setq battery-update-timer (run-at-time nil battery-update-interval
 177                                             'battery-update-handler))
 178     (battery-update)))
 179
 180 (defun battery-update-handler ()
 181   (battery-update)
 182   (sit-for 0))
 183
 184 (defun battery-update ()
 185   "Update battery status information in the mode line."
 186   (setq battery-mode-line-string
 187         (propertize (if (and battery-mode-line-format
 188                              battery-status-function)
 189                         (battery-format
 190                          battery-mode-line-format
 191                          (funcall battery-status-function))
 192                       "")
 193                     'help-echo "Battery status information"))
 194   (force-mode-line-update))
 195
 196 \f
 197 ;;; `/proc/apm' interface for Linux.
 198
 199 (defconst battery-linux-proc-apm-regexp
 200   (concat "^\\([^ ]+\\)"                ; Driver version.
 201           " \\([^ ]+\\)"                ; APM BIOS version.
 202           " 0x\\([0-9a-f]+\\)"          ; APM BIOS flags.
 203           " 0x\\([0-9a-f]+\\)"          ; AC line status.
 204           " 0x\\([0-9a-f]+\\)"          ; Battery status.
 205           " 0x\\([0-9a-f]+\\)"          ; Battery flags.
 206           " \\(-?[0-9]+\\)%"            ; Load percentage.
 207           " \\(-?[0-9]+\\)"             ; Remaining time.
 208           " \\(.*\\)"                   ; Time unit.
 209           "$")
 210   "Regular expression matching contents of `/proc/apm'.")
 211
 212 (defun battery-linux-proc-apm ()
 213   "Get APM status information from Linux kernel.
 214 This function works only with the new `/proc/apm' format introduced
 215 in Linux version 1.3.58.
 216
 217 The following %-sequences are provided:
 218 %v Linux driver version
 219 %V APM BIOS version
 220 %I APM BIOS status (verbose)
 221 %L AC line status (verbose)
 222 %B Battery status (verbose)
 223 %b Battery status, empty means high, `-' means low,
 224    `!' means critical, and `+' means charging
 225 %p Battery load percentage
 226 %s Remaining time (to charge or discharge) in seconds
 227 %m Remaining time (to charge or discharge) in minutes
 228 %h Remaining time (to charge or discharge) in hours
 229 %t Remaining time (to charge or discharge) in the form `h:min'"
 230   (let (driver-version bios-version bios-interface line-status
 231         battery-status battery-status-symbol load-percentage
 232         seconds minutes hours remaining-time tem)
 233     (with-temp-buffer
 234       (ignore-errors (insert-file-contents "/proc/apm"))
 235       (when (re-search-forward battery-linux-proc-apm-regexp)
 236         (setq driver-version (match-string 1))
 237         (setq bios-version (match-string 2))
 238         (setq tem (string-to-number (match-string 3) 16))
 239         (if (not (logand tem 2))
 240             (setq bios-interface "not supported")
 241           (setq bios-interface "enabled")
 242           (cond ((logand tem 16) (setq bios-interface "disabled"))
 243                 ((logand tem 32) (setq bios-interface "disengaged")))
 244           (setq tem (string-to-number (match-string 4) 16))
 245           (cond ((= tem 0) (setq line-status "off-line"))
 246                 ((= tem 1) (setq line-status "on-line"))
 247                 ((= tem 2) (setq line-status "on backup")))
 248           (setq tem (string-to-number (match-string 6) 16))
 249           (if (= tem 255)
 250               (setq battery-status "N/A")
 251             (setq tem (string-to-number (match-string 5) 16))
 252             (cond ((= tem 0) (setq battery-status "high"
 253                                    battery-status-symbol ""))
 254                   ((= tem 1) (setq battery-status "low"
 255                                    battery-status-symbol "-"))
 256                   ((= tem 2) (setq battery-status "critical"
 257                                    battery-status-symbol "!"))
 258                   ((= tem 3) (setq battery-status "charging"
 259                                    battery-status-symbol "+")))
 260             (setq load-percentage (match-string 7))
 261             (setq seconds (string-to-number (match-string 8)))
 262             (and (string-equal (match-string 9) "min")
 263                  (setq seconds (* 60 seconds)))
 264             (setq minutes (/ seconds 60)
 265                   hours (/ seconds 3600))
 266             (setq remaining-time
 267                   (format "%d:%02d" hours (- minutes (* 60 hours))))))))
 268     (list (cons ?v (or driver-version "N/A"))
 269           (cons ?V (or bios-version "N/A"))
 270           (cons ?I (or bios-interface "N/A"))
 271           (cons ?L (or line-status "N/A"))
 272           (cons ?B (or battery-status "N/A"))
 273           (cons ?b (or battery-status-symbol ""))
 274           (cons ?p (or load-percentage "N/A"))
 275           (cons ?s (or (and seconds (number-to-string seconds)) "N/A"))
 276           (cons ?m (or (and minutes (number-to-string minutes)) "N/A"))
 277           (cons ?h (or (and hours (number-to-string hours)) "N/A"))
 278           (cons ?t (or remaining-time "N/A")))))
 279
 280 \f
 281 ;;; `/proc/acpi/' interface for Linux.
 282
 283 (defun battery-linux-proc-acpi ()
 284   "Get ACPI status information from Linux kernel.
 285 This function works only with the `/proc/acpi/' format introduced
 286 in Linux version 2.4.20 and 2.6.0.
 287
 288 The following %-sequences are provided:
 289 %c Current capacity (mAh)
 290 %r Current rate
 291 %B Battery status (verbose)
 292 %b Battery status, empty means high, `-' means low,
 293    `!' means critical, and `+' means charging
 294 %d Temperature (in degrees Celsius)
 295 %L AC line status (verbose)
 296 %p Battery load percentage
 297 %m Remaining time (to charge or discharge) in minutes
 298 %h Remaining time (to charge or discharge) in hours
 299 %t Remaining time (to charge or discharge) in the form `h:min'"
 300   (let ((design-capacity 0)
 301         (last-full-capacity 0)
 302         full-capacity
 303         (warn 0)
 304         (low 0)
 305         capacity rate rate-type charging-state minutes hours)
 306     ;; ACPI provides information about each battery present in the system in
 307     ;; a separate subdirectory.  We are going to merge the available
 308     ;; information together since displaying for a variable amount of
 309     ;; batteries seems overkill for format-strings.
 310     (with-temp-buffer
 311       (dolist (dir (ignore-errors (directory-files "/proc/acpi/battery/"
 312                                                    t "\\`[^.]")))
 313         (erase-buffer)
 314         (ignore-errors (insert-file-contents (expand-file-name "state" dir)))
 315         (when (re-search-forward "present: +yes$" nil t)
 316           (and (re-search-forward "charging state: +\\(.*\\)$" nil t)
 317                (member charging-state '("unknown" "charged" nil))
 318                ;; On most multi-battery systems, most of the time only one
 319                ;; battery is "charging"/"discharging", the others are
 320                ;; "unknown".
 321                (setq charging-state (match-string 1)))
 322           (when (re-search-forward "present rate: +\\([0-9]+\\) \\(m[AW]\\)$"
 323                                    nil t)
 324             (setq rate (+ (or rate 0) (string-to-number (match-string 1)))
 325                   rate-type (or (and rate-type
 326                                      (if (string= rate-type (match-string 2))
 327                                          rate-type
 328                                        (error
 329                                         "Inconsistent rate types (%s vs. %s)"
 330                                         rate-type (match-string 2))))
 331                                 (match-string 2))))
 332           (when (re-search-forward "remaining capacity: +\\([0-9]+\\) m[AW]h$"
 333                                    nil t)
 334             (setq capacity
 335                   (+ (or capacity 0) (string-to-number (match-string 1))))))
 336         (goto-char (point-max))
 337         (ignore-errors (insert-file-contents (expand-file-name "info" dir)))
 338         (when (re-search-forward "present: +yes$" nil t)
 339           (when (re-search-forward "design capacity: +\\([0-9]+\\) m[AW]h$"
 340                                    nil t)
 341             (incf design-capacity (string-to-number (match-string 1))))
 342           (when (re-search-forward "last full capacity: +\\([0-9]+\\) m[AW]h$"
 343                                    nil t)
 344             (incf last-full-capacity (string-to-number (match-string 1))))
 345           (when (re-search-forward
 346                  "design capacity warning: +\\([0-9]+\\) m[AW]h$" nil t)
 347             (incf warn (string-to-number (match-string 1))))
 348           (when (re-search-forward "design capacity low: +\\([0-9]+\\) m[AW]h$"
 349                                    nil t)
 350             (incf low (string-to-number (match-string 1)))))))
 351     (setq full-capacity (if (> last-full-capacity 0)
 352                             last-full-capacity design-capacity))
 353     (and capacity rate
 354          (setq minutes (if (zerop rate) 0
 355                          (floor (* (/ (float (if (string= charging-state
 356                                                           "charging")
 357                                                  (- full-capacity capacity)
 358                                                capacity))
 359                                       rate)
 360                                    60)))
 361                hours (/ minutes 60)))
 362     (list (cons ?c (or (and capacity (number-to-string capacity)) "N/A"))
 363           (cons ?L (or (battery-search-for-one-match-in-files
 364                         (mapcar (lambda (e) (concat e "/state"))
 365                                 (ignore-errors
 366                                   (directory-files "/proc/acpi/ac_adapter/"
 367                                                    t "\\`[^.]")))
 368                         "state: +\\(.*\\)$" 1)
 369
 370                        "N/A"))
 371           (cons ?d (or (battery-search-for-one-match-in-files
 372                         (mapcar (lambda (e) (concat e "/temperature"))
 373                                 (ignore-errors
 374                                   (directory-files "/proc/acpi/thermal_zone/"
 375                                                    t "\\`[^.]")))
 376                         "temperature: +\\([0-9]+\\) C$" 1)
 377
 378                        "N/A"))
 379           (cons ?r (or (and rate (concat (number-to-string rate) " "
 380                                          rate-type)) "N/A"))
 381           (cons ?B (or charging-state "N/A"))
 382           (cons ?b (or (and (string= charging-state "charging") "+")
 383                        (and capacity (< capacity low) "!")
 384                        (and capacity (< capacity warn) "-")
 385                        ""))
 386           (cons ?h (or (and hours (number-to-string hours)) "N/A"))
 387           (cons ?m (or (and minutes (number-to-string minutes)) "N/A"))
 388           (cons ?t (or (and minutes
 389                             (format "%d:%02d" hours (- minutes (* 60 hours))))
 390                        "N/A"))
 391           (cons ?p (or (and full-capacity capacity
 392                             (> full-capacity 0)
 393                             (number-to-string
 394                              (floor (/ capacity
 395                                        (/ (float full-capacity) 100)))))
 396                        "N/A")))))
 397
 398 \f
 399 ;;; `/sys/class/power_supply/BATN' interface for Linux.
 400
 401 (defun battery-linux-sysfs ()
 402   "Get ACPI status information from Linux kernel.
 403 This function works only with the new `/sys/class/power_supply/'
 404 format introduced in Linux version 2.4.25.
 405
 406 The following %-sequences are provided:
 407 %c Current capacity (mAh or mWh)
 408 %B Battery status (verbose)
 409 %p Battery load percentage
 410 %L AC line status (verbose)"
 411   (let (charging-state
 412         (charge-full 0.0)
 413         (charge-now 0.0)
 414         (energy-full 0.0)
 415         (energy-now 0.0))
 416     ;; SysFS provides information about each battery present in the
 417     ;; system in a separate subdirectory.  We are going to merge the
 418     ;; available information together.
 419     (with-temp-buffer
 420       (dolist (dir (ignore-errors
 421                     (directory-files
 422                      "/sys/class/power_supply/" t "BAT[0-9]$")))
 423         (erase-buffer)
 424         (ignore-errors (insert-file-contents
 425                         (expand-file-name "uevent" dir)))
 426         (when (re-search-forward "POWER_SUPPLY_PRESENT=1$" nil t)
 427           (goto-char (point-min))
 428           (and (re-search-forward "POWER_SUPPLY_STATUS=\\(.*\\)$" nil t)
 429                (member charging-state '("Unknown" "Full" nil))
 430                (setq charging-state (match-string 1)))
 431           (let (full-string now-string)
 432             ;; Sysfs may list either charge (mAh) or energy (mWh).
 433             ;; Keep track of both, and choose which to report later.
 434             (cond ((and (re-search-forward
 435                          "POWER_SUPPLY_CHARGE_FULL=\\([0-9]*\\)$" nil t)
 436                         (setq full-string (match-string 1))
 437                         (re-search-forward
 438                          "POWER_SUPPLY_CHARGE_NOW=\\([0-9]*\\)$" nil t)
 439                         (setq now-string (match-string 1)))
 440                    (setq charge-full (+ charge-full
 441                                         (string-to-number full-string))
 442                          charge-now  (+ charge-now
 443                                         (string-to-number now-string))))
 444                   ((and (re-search-forward
 445                          "POWER_SUPPLY_ENERGY_FULL=\\([0-9]*\\)$" nil t)
 446                         (setq full-string (match-string 1))
 447                         (re-search-forward
 448                          "POWER_SUPPLY_ENERGY_NOW=\\([0-9]*\\)$" nil t)
 449                         (setq now-string (match-string 1)))
 450                    (setq energy-full (+ energy-full
 451                                         (string-to-number full-string))
 452                          energy-now  (+ energy-now
 453                                         (string-to-number now-string)))))))))
 454     (list (cons ?c (cond ((or (> charge-full 0) (> charge-now 0))
 455                           (number-to-string charge-now))
 456                          ((or (> energy-full 0) (> energy-now 0))
 457                           (number-to-string energy-now))
 458                          (t "N/A")))
 459           (cons ?B (or charging-state "N/A"))
 460           (cons ?p (cond ((> charge-full 0)
 461                           (format "%.1f"
 462                                   (/ (* 100 charge-now) charge-full)))
 463                          ((> energy-full 0)
 464                           (format "%.1f"
 465                                   (/ (* 100 energy-now) energy-full)))
 466                          (t "N/A")))
 467           (cons ?L (if (file-readable-p "/sys/class/power_supply/AC/online")
 468                        (if (battery-search-for-one-match-in-files
 469                             (list "/sys/class/power_supply/AC/online"
 470                                   "/sys/class/power_supply/ACAD/online")
 471                             "1" 0)
 472                            "AC"
 473                          "BAT")
 474                      "N/A")))))
 475
 476
 477 \f
 478 ;;; `pmset' interface for Darwin (OS X).
 479
 480 (defun battery-pmset ()
 481   "Get battery status information using `pmset'.
 482
 483 The following %-sequences are provided:
 484 %L Power source (verbose)
 485 %B Battery status (verbose)
 486 %b Battery status, empty means high, `-' means low,
 487    `!' means critical, and `+' means charging
 488 %p Battery load percentage
 489 %h Remaining time in hours
 490 %m Remaining time in minutes
 491 %t Remaining time in the form `h:min'"
 492   (let (power-source load-percentage battery-status battery-status-symbol
 493         remaining-time hours minutes)
 494     (with-temp-buffer
 495       (ignore-errors (call-process "pmset" nil t nil "-g" "ps"))
 496       (goto-char (point-min))
 497       (when (re-search-forward "Currentl?y drawing from '\\(AC\\|Battery\\) Power'" nil t)
 498         (setq power-source (match-string 1))
 499         (when (re-search-forward "^ -InternalBattery-0[ \t]+" nil t)
 500           (when (looking-at "\\([0-9]\\{1,3\\}\\)%")
 501             (setq load-percentage (match-string 1))
 502             (goto-char (match-end 0))
 503             (cond ((looking-at "; charging")
 504                    (setq battery-status "charging"
 505                          battery-status-symbol "+"))
 506                   ((< (string-to-number load-percentage) battery-load-low)
 507                    (setq battery-status "low"
 508                          battery-status-symbol "-"))
 509                   ((< (string-to-number load-percentage) battery-load-critical)
 510                    (setq battery-status "critical"
 511                          battery-status-symbol "!"))
 512                   (t
 513                    (setq battery-status "high"
 514                          battery-status-symbol "")))
 515             (when (re-search-forward "\\(\\([0-9]+\\):\\([0-9]+\\)\\) remaining"  nil t)
 516               (setq remaining-time (match-string 1))
 517               (let ((h (string-to-number (match-string 2)))
 518                     (m (string-to-number (match-string 3))))
 519                 (setq hours (number-to-string (+ h (if (< m 30) 0 1)))
 520                       minutes (number-to-string (+ (* h 60) m)))))))))
 521     (list (cons ?L (or power-source "N/A"))
 522           (cons ?p (or load-percentage "N/A"))
 523           (cons ?B (or battery-status "N/A"))
 524           (cons ?b (or battery-status-symbol ""))
 525           (cons ?h (or hours "N/A"))
 526           (cons ?m (or minutes "N/A"))
 527           (cons ?t (or remaining-time "N/A")))))
 528
 529 \f
 530 ;;; Private functions.
 531
 532 (defun battery-format (format alist)
 533   "Substitute %-sequences in FORMAT."
 534   (replace-regexp-in-string
 535    "%."
 536    (lambda (str)
 537      (let ((char (aref str 1)))
 538        (if (eq char ?%) "%"
 539          (or (cdr (assoc char alist)) ""))))
 540    format t t))
 541
 542 (defun battery-search-for-one-match-in-files (files regexp match-num)
 543   "Search REGEXP in the content of the files listed in FILES.
 544 If a match occurred, return the parenthesized expression numbered by
 545 MATCH-NUM in the match.  Otherwise, return nil."
 546   (with-temp-buffer
 547     (catch 'found
 548       (dolist (file files)
 549         (and (ignore-errors (insert-file-contents file nil nil nil 'replace))
 550              (re-search-forward regexp nil t)
 551              (throw 'found (match-string match-num)))))))
 552
 553 \f
 554 (provide 'battery)
 555
 556 ;;; battery.el ends here