lisp/gnus/gnus-spec.el

   1 ;;; gnus-spec.el --- format spec functions for Gnus
   2
   3 ;; Copyright (C) 1996-2012 Free Software Foundation, Inc.
   4
   5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   6 ;; Keywords: news
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;;; Code:
  26
  27 ;; For Emacs <22.2 and XEmacs.
  28 (eval-and-compile
  29   (unless (fboundp 'declare-function) (defmacro declare-function (&rest r))))
  30 (eval-when-compile (require 'cl))
  31 (defvar gnus-newsrc-file-version)
  32
  33 (require 'gnus)
  34
  35 (defcustom gnus-use-correct-string-widths (featurep 'xemacs)
  36   "*If non-nil, use correct functions for dealing with wide characters."
  37   :version "22.1"
  38   :group 'gnus-format
  39   :type 'boolean)
  40
  41 (defcustom gnus-make-format-preserve-properties (featurep 'xemacs)
  42   "*If non-nil, use a replacement `format' function which preserves
  43 text properties. This is only needed on XEmacs, as Emacs does this anyway."
  44   :version "22.1"
  45   :group 'gnus-format
  46   :type 'boolean)
  47
  48 ;;; Internal variables.
  49
  50 (defvar gnus-summary-mark-positions nil)
  51 (defvar gnus-group-mark-positions nil)
  52 (defvar gnus-group-indentation "")
  53
  54 ;; Format specs.  The chunks below are the machine-generated forms
  55 ;; that are to be evalled as the result of the default format strings.
  56 ;; We write them in here to get them byte-compiled.  That way the
  57 ;; default actions will be quite fast, while still retaining the full
  58 ;; flexibility of the user-defined format specs.
  59
  60 ;; First we have lots of dummy defvars to let the compiler know these
  61 ;; are really dynamic variables.
  62
  63 (defvar gnus-tmp-unread)
  64 (defvar gnus-tmp-replied)
  65 (defvar gnus-tmp-score-char)
  66 (defvar gnus-tmp-indentation)
  67 (defvar gnus-tmp-opening-bracket)
  68 (defvar gnus-tmp-lines)
  69 (defvar gnus-tmp-name)
  70 (defvar gnus-tmp-closing-bracket)
  71 (defvar gnus-tmp-subject-or-nil)
  72 (defvar gnus-tmp-subject)
  73 (defvar gnus-tmp-marked)
  74 (defvar gnus-tmp-marked-mark)
  75 (defvar gnus-tmp-subscribed)
  76 (defvar gnus-tmp-process-marked)
  77 (defvar gnus-tmp-number-of-unread)
  78 (defvar gnus-tmp-group-name)
  79 (defvar gnus-tmp-group)
  80 (defvar gnus-tmp-article-number)
  81 (defvar gnus-tmp-unread-and-unselected)
  82 (defvar gnus-tmp-news-method)
  83 (defvar gnus-tmp-news-server)
  84 (defvar gnus-tmp-article-number)
  85 (defvar gnus-mouse-face)
  86 (defvar gnus-mouse-face-prop)
  87 (defvar gnus-tmp-header)
  88 (defvar gnus-tmp-from)
  89
  90 (declare-function gnus-summary-from-or-to-or-newsgroups "gnus-sum"
  91                   (header gnus-tmp-from))
  92
  93 (defmacro gnus-lrm-string-p (string)
  94   (if (fboundp 'bidi-string-mark-left-to-right)
  95       ;; LRM, RLM, PDF characters as integers to avoid breaking Emacs
  96       ;; 23.
  97       `(memq (aref ,string (1- (length ,string))) '(8206 8207 8236))
  98     nil))
  99
 100 (defvar gnus-lrm-string (if (ignore-errors (string 8206))
 101                             (propertize (string 8206) 'invisible t)
 102                           ""))
 103
 104 (defvar gnus-summary-line-format-spec nil)
 105 (defvar gnus-summary-dummy-line-format-spec nil)
 106 (defvar gnus-group-line-format-spec nil)
 107
 108 (defvar gnus-format-specs
 109   `((version . ,emacs-version)
 110     (gnus-version . ,(gnus-continuum-version)))
 111   "Alist of format specs.")
 112
 113 (defvar gnus-default-format-specs gnus-format-specs)
 114
 115 (defvar gnus-article-mode-line-format-spec nil)
 116 (defvar gnus-summary-mode-line-format-spec nil)
 117 (defvar gnus-group-mode-line-format-spec nil)
 118
 119 ;;; Phew.  All that gruft is over with, fortunately.
 120
 121 ;;;###autoload
 122 (defun gnus-update-format (var)
 123   "Update the format specification near point."
 124   (interactive
 125    (list
 126     (save-excursion
 127       (eval-defun nil)
 128       ;; Find the end of the current word.
 129       (re-search-forward "[ \t\n]" nil t)
 130       ;; Search backward.
 131       (when (re-search-backward "\\(gnus-[-a-z]+-line-format\\)" nil t)
 132         (match-string 1)))))
 133   (let* ((type (intern (progn (string-match "gnus-\\([-a-z]+\\)-line" var)
 134                               (match-string 1 var))))
 135          (entry (assq type gnus-format-specs))
 136          value spec)
 137     (when entry
 138       (setq gnus-format-specs (delq entry gnus-format-specs)))
 139     (set
 140      (intern (format "%s-spec" var))
 141      (gnus-parse-format (setq value (symbol-value (intern var)))
 142                         (symbol-value (intern (format "%s-alist" var)))
 143                         (not (string-match "mode" var))))
 144     (setq spec (symbol-value (intern (format "%s-spec" var))))
 145     (push (list type value spec) gnus-format-specs)
 146
 147     (pop-to-buffer "*Gnus Format*")
 148     (erase-buffer)
 149     (lisp-interaction-mode)
 150     (insert (gnus-pp-to-string spec))))
 151
 152 (defun gnus-update-format-specifications (&optional force &rest types)
 153   "Update all (necessary) format specifications.
 154 Return a list of updated types."
 155   ;; Make the indentation array.
 156   ;; See whether all the stored info needs to be flushed.
 157   (when (or force
 158             (not gnus-newsrc-file-version)
 159             (not (equal (gnus-continuum-version)
 160                         (gnus-continuum-version gnus-newsrc-file-version)))
 161             (not (equal emacs-version
 162                         (cdr (assq 'version gnus-format-specs)))))
 163     (setq gnus-format-specs nil))
 164   ;; Go through all the formats and see whether they need updating.
 165   (let (new-format entry type val updated)
 166     (while (setq type (pop types))
 167       ;; Jump to the proper buffer to find out the value of the
 168       ;; variable, if possible.  (It may be buffer-local.)
 169       (save-excursion
 170         (let ((buffer (intern (format "gnus-%s-buffer" type))))
 171           (when (and (boundp buffer)
 172                      (setq val (symbol-value buffer))
 173                      (gnus-buffer-exists-p val))
 174             (set-buffer val))
 175           (setq new-format (symbol-value
 176                             (intern (format "gnus-%s-line-format" type)))))
 177         (setq entry (cdr (assq type gnus-format-specs)))
 178         (if (and (car entry)
 179                  (equal (car entry) new-format))
 180             ;; Use the old format.
 181             (set (intern (format "gnus-%s-line-format-spec" type))
 182                  (cadr entry))
 183           ;; This is a new format.
 184           (setq val
 185                 (if (not (stringp new-format))
 186                     ;; This is a function call or something.
 187                     new-format
 188                   ;; This is a "real" format.
 189                   (gnus-parse-format
 190                    new-format
 191                    (symbol-value
 192                     (intern (format "gnus-%s-line-format-alist" type)))
 193                    (not (string-match "mode$" (symbol-name type))))))
 194           ;; Enter the new format spec into the list.
 195           (if entry
 196               (progn
 197                 (setcar (cdr entry) val)
 198                 (setcar entry new-format))
 199             (push (list type new-format val) gnus-format-specs))
 200           (set (intern (format "gnus-%s-line-format-spec" type)) val)
 201           (push type updated))))
 202
 203     (unless (assq 'version gnus-format-specs)
 204       (push (cons 'version emacs-version) gnus-format-specs))
 205     updated))
 206
 207 (defcustom gnus-mouse-face-0 'highlight
 208   "The \"%(hello%)\" face."
 209   :group 'gnus-format
 210   :type 'face)
 211
 212 (defcustom gnus-mouse-face-1 'highlight
 213   "The \"%1(hello%)\" face."
 214   :group 'gnus-format
 215   :type 'face)
 216
 217 (defcustom gnus-mouse-face-2 'highlight
 218   "The \"%2(hello%)\" face."
 219   :group 'gnus-format
 220   :type 'face)
 221
 222 (defcustom gnus-mouse-face-3 'highlight
 223   "The \"%3(hello%)\" face."
 224   :group 'gnus-format
 225   :type 'face)
 226
 227 (defcustom gnus-mouse-face-4 'highlight
 228   "The \"%4(hello%)\" face."
 229   :group 'gnus-format
 230   :type 'face)
 231
 232 (defun gnus-mouse-face-function (form type)
 233   `(gnus-put-text-property
 234     (point) (progn ,@form (point))
 235     gnus-mouse-face-prop
 236     ,(if (equal type 0)
 237          'gnus-mouse-face
 238        `(quote ,(symbol-value (intern (format "gnus-mouse-face-%d" type)))))))
 239
 240 (defcustom gnus-face-0 'bold
 241   "The \"%{hello%}\" face."
 242   :group 'gnus-format
 243   :type 'face)
 244
 245 (defcustom gnus-face-1 'italic
 246   "The \"%1{hello%}\" face."
 247   :group 'gnus-format
 248   :type 'face)
 249
 250 (defcustom gnus-face-2 'bold-italic
 251   "The \"%2{hello%}\" face."
 252   :group 'gnus-format
 253   :type 'face)
 254
 255 (defcustom gnus-face-3 'bold
 256   "The \"%3{hello%}\" face."
 257   :group 'gnus-format
 258   :type 'face)
 259
 260 (defcustom gnus-face-4 'bold
 261   "The \"%4{hello%}\" face."
 262   :group 'gnus-format
 263   :type 'face)
 264
 265 (defun gnus-face-face-function (form type)
 266   `(gnus-add-text-properties
 267     (point) (progn ,@form (point))
 268     '(gnus-face t face ,(symbol-value (intern (format "gnus-face-%d" type))))))
 269
 270 (defun gnus-balloon-face-function (form type)
 271   `(gnus-put-text-property
 272     (point) (progn ,@form (point))
 273     ,(if (fboundp 'balloon-help-mode)
 274          ''balloon-help
 275        ''help-echo)
 276     ,(intern (format "gnus-balloon-face-%d" type))))
 277
 278 (defun gnus-spec-tab (column)
 279   (if (> column 0)
 280       `(insert-char ?  (max (- ,column (current-column)) 0))
 281     (let ((column (abs column)))
 282       `(if (> (current-column) ,column)
 283            (let ((end (point)))
 284              (if (= (move-to-column ,column) ,column)
 285                  (delete-region (point) end)
 286                (delete-region (1- (point)) end)
 287                (insert " ")))
 288          (insert-char ?  (max (- ,column (current-column)) 0))))))
 289
 290 (defun gnus-correct-length (string)
 291   "Return the correct width of STRING."
 292   (apply #'+ (mapcar #'char-width string)))
 293
 294 (defun gnus-correct-substring (string start &optional end)
 295   (let ((wstart 0)
 296         (wend 0)
 297         (wseek 0)
 298         (seek 0)
 299         (length (length string))
 300         (string (concat string "\0")))
 301     ;; Find the start position.
 302     (while (and (< seek length)
 303                 (< wseek start))
 304       (incf wseek (char-width (aref string seek)))
 305       (incf seek))
 306     (setq wstart seek)
 307     ;; Find the end position.
 308     (while (and (<= seek length)
 309                 (or (not end)
 310                     (<= wseek end)))
 311       (incf wseek (char-width (aref string seek)))
 312       (incf seek))
 313     (setq wend seek)
 314     (substring string wstart (1- wend))))
 315
 316 (defun gnus-string-width-function ()
 317   (cond
 318    (gnus-use-correct-string-widths
 319     'gnus-correct-length)
 320    ((fboundp 'string-width)
 321     'string-width)
 322    (t
 323     'length)))
 324
 325 (defun gnus-substring-function ()
 326   (cond
 327    (gnus-use-correct-string-widths
 328     'gnus-correct-substring)
 329    ((fboundp 'string-width)
 330     'gnus-correct-substring)
 331    (t
 332     'substring)))
 333
 334 (defun gnus-tilde-max-form (el max-width)
 335   "Return a form that limits EL to MAX-WIDTH."
 336   (let ((max (abs max-width))
 337         (length-fun (gnus-string-width-function))
 338         (substring-fun (gnus-substring-function)))
 339     (if (symbolp el)
 340         `(if (> (,length-fun ,el) ,max)
 341              ,(if (< max-width 0)
 342                   `(,substring-fun ,el (- (,length-fun ,el) ,max))
 343                 `(if (gnus-lrm-string-p ,el)
 344                      (concat (,substring-fun ,el 0 ,max) ,gnus-lrm-string)
 345                    (,substring-fun ,el 0 ,max)))
 346            ,el)
 347       `(let ((val (eval ,el)))
 348          (if (> (,length-fun val) ,max)
 349              ,(if (< max-width 0)
 350                   `(,substring-fun val (- (,length-fun val) ,max))
 351                 `(if (gnus-lrm-string-p val)
 352                      (concat (,substring-fun val 0 ,max) ,gnus-lrm-string)
 353                    (,substring-fun val 0 ,max)))
 354            val)))))
 355
 356 (defun gnus-tilde-cut-form (el cut-width)
 357   "Return a form that cuts CUT-WIDTH off of EL."
 358   (let ((cut (abs cut-width))
 359         (length-fun (gnus-string-width-function))
 360         (substring-fun (gnus-substring-function)))
 361     (if (symbolp el)
 362         `(if (> (,length-fun ,el) ,cut)
 363              ,(if (< cut-width 0)
 364                   `(,substring-fun ,el 0 (- (,length-fun ,el) ,cut))
 365                 `(,substring-fun ,el ,cut))
 366            ,el)
 367       `(let ((val (eval ,el)))
 368          (if (> (,length-fun val) ,cut)
 369              ,(if (< cut-width 0)
 370                   `(,substring-fun val 0 (- (,length-fun val) ,cut))
 371                 `(,substring-fun val ,cut))
 372            val)))))
 373
 374 (defun gnus-tilde-ignore-form (el ignore-value)
 375   "Return a form that is blank when EL is IGNORE-VALUE."
 376   (if (symbolp el)
 377       `(if (equal ,el ,ignore-value)
 378            "" ,el)
 379     `(let ((val (eval ,el)))
 380        (if (equal val ,ignore-value)
 381            "" val))))
 382
 383 (defun gnus-pad-form (el pad-width)
 384   "Return a form that pads EL to PAD-WIDTH accounting for multi-column
 385 characters correctly. This is because `format' may pad to columns or to
 386 characters when given a pad value."
 387   (let ((pad (abs pad-width))
 388         (side (< 0 pad-width))
 389         (length-fun (gnus-string-width-function)))
 390     (if (symbolp el)
 391         `(let ((need (- ,pad (,length-fun ,el))))
 392            (if (> need 0)
 393                (concat ,(when side '(make-string need ?\ ))
 394                        ,el
 395                        ,(when (not side) '(make-string need ?\ )))
 396              ,el))
 397       `(let* ((val (eval ,el))
 398               (need (- ,pad (,length-fun val))))
 399          (if (> need 0)
 400              (concat ,(when side '(make-string need ?\ ))
 401                      val
 402                      ,(when (not side) '(make-string need ?\ )))
 403            val)))))
 404
 405 (defun gnus-parse-format (format spec-alist &optional insert)
 406   ;; This function parses the FORMAT string with the help of the
 407   ;; SPEC-ALIST and returns a list that can be eval'ed to return the
 408   ;; string.  If the FORMAT string contains the specifiers %( and %)
 409   ;; the text between them will have the mouse-face text property.
 410   ;; If the FORMAT string contains the specifiers %[ and %], the text between
 411   ;; them will have the balloon-help text property.
 412   (let ((case-fold-search nil))
 413     (if (string-match
 414          "\\`\\(.*\\)%[0-9]?[{(«]\\(.*\\)%[0-9]?[»})]\\(.*\n?\\)\\'\\|%[-0-9]*=\\|%[-0-9]*\\*"
 415          format)
 416         (gnus-parse-complex-format format spec-alist)
 417       ;; This is a simple format.
 418       (gnus-parse-simple-format format spec-alist insert))))
 419
 420 (defun gnus-parse-complex-format (format spec-alist)
 421   (let ((cursor-spec nil))
 422     (save-excursion
 423       (gnus-set-work-buffer)
 424       (insert format)
 425       (goto-char (point-min))
 426       (while (re-search-forward "\"" nil t)
 427         (replace-match "\\\"" nil t))
 428       (goto-char (point-min))
 429       (insert "(\"")
 430       ;; Convert all font specs into font spec lists.
 431       (while (re-search-forward "%\\([0-9]+\\)?\\([«»{}()]\\)" nil t)
 432         (let ((number (if (match-beginning 1)
 433                           (match-string 1) "0"))
 434               (delim (aref (match-string 2) 0)))
 435           (if (or (= delim ?\()
 436                   (= delim ?\{)
 437                   (= delim ?\«))
 438               (replace-match (concat "\"("
 439                                      (cond ((= delim ?\() "mouse")
 440                                            ((= delim ?\{) "face")
 441                                            (t "balloon"))
 442                                      " " number " \"")
 443                              t t)
 444             (replace-match "\")\""))))
 445       (goto-char (point-max))
 446       (insert "\")")
 447       ;; Convert point position commands.
 448       (goto-char (point-min))
 449       (let ((case-fold-search nil))
 450         (while (re-search-forward "%\\([-0-9]+\\)?\\*" nil t)
 451           (replace-match "\"(point)\"" t t)
 452           (setq cursor-spec t)))
 453       ;; Convert TAB commands.
 454       (goto-char (point-min))
 455       (while (re-search-forward "%\\([-0-9]+\\)=" nil t)
 456         (replace-match (format "\"(tab %s)\"" (match-string 1)) t t))
 457       ;; Convert the buffer into the spec.
 458       (goto-char (point-min))
 459       (let ((form (read (current-buffer))))
 460         (if cursor-spec
 461             `(let (gnus-position)
 462                ,@(gnus-complex-form-to-spec form spec-alist)
 463                (if gnus-position
 464                    (gnus-put-text-property gnus-position (1+ gnus-position)
 465                                            'gnus-position t)))
 466           `(progn
 467              ,@(gnus-complex-form-to-spec form spec-alist)))))))
 468
 469 (defun gnus-complex-form-to-spec (form spec-alist)
 470   (delq nil
 471         (mapcar
 472          (lambda (sform)
 473            (cond
 474             ((stringp sform)
 475              (gnus-parse-simple-format sform spec-alist t))
 476             ((eq (car sform) 'point)
 477              '(setq gnus-position (point)))
 478             ((eq (car sform) 'tab)
 479              (gnus-spec-tab (cadr sform)))
 480             (t
 481              (funcall (intern (format "gnus-%s-face-function" (car sform)))
 482                       (gnus-complex-form-to-spec (cddr sform) spec-alist)
 483                       (nth 1 sform)))))
 484          form)))
 485
 486
 487 (defun gnus-xmas-format (fstring &rest args)
 488   "A version of `format' which preserves text properties.
 489
 490 Required for XEmacs, where the built in `format' function strips all text
 491 properties from both the format string and any inserted strings.
 492
 493 Only supports the format sequence %s, and %% for inserting
 494 literal % characters. A pad width and an optional - (to right pad)
 495 are supported for %s."
 496   (let ((re "%%\\|%\\(-\\)?\\([1-9][0-9]*\\)?s")
 497         (n (length args)))
 498     (with-temp-buffer
 499       (insert fstring)
 500       (goto-char (point-min))
 501       (while (re-search-forward re nil t)
 502         (goto-char (match-end 0))
 503         (cond
 504          ((string= (match-string 0) "%%")
 505           (delete-char -1))
 506          (t
 507           (if (null args)
 508               (error 'wrong-number-of-arguments #'my-format n fstring))
 509           (let* ((minlen (string-to-number (or (match-string 2) "")))
 510                  (arg (car args))
 511                  (str (if (stringp arg) arg (format "%s" arg)))
 512                  (lpad (null (match-string 1)))
 513                  (padlen (max 0 (- minlen (length str)))))
 514             (replace-match "")
 515             (if lpad (insert-char ?\  padlen))
 516             (insert str)
 517             (unless lpad (insert-char ?\  padlen))
 518             (setq args (cdr args))))))
 519       (buffer-string))))
 520
 521 (defun gnus-parse-simple-format (format spec-alist &optional insert)
 522   ;; This function parses the FORMAT string with the help of the
 523   ;; SPEC-ALIST and returns a list that can be eval'ed to return a
 524   ;; string.
 525   (let ((max-width 0)
 526         spec flist fstring elem result dontinsert user-defined
 527         type value pad-width spec-beg cut-width ignore-value
 528         tilde-form tilde elem-type extended-spec)
 529     (save-excursion
 530       (gnus-set-work-buffer)
 531       (insert format)
 532       (goto-char (point-min))
 533       (while (re-search-forward "%" nil t)
 534         (setq user-defined nil
 535               spec-beg nil
 536               pad-width nil
 537               max-width nil
 538               cut-width nil
 539               ignore-value nil
 540               tilde-form nil
 541               extended-spec nil)
 542         (setq spec-beg (1- (point)))
 543
 544         ;; Parse this spec fully.
 545         (while
 546             (cond
 547              ((looking-at "\\([-.0-9]+\\)\\(,[-0-9]+\\)?")
 548               (setq pad-width (string-to-number (match-string 1)))
 549               (when (match-beginning 2)
 550                 (setq max-width (string-to-number (buffer-substring
 551                                                    (1+ (match-beginning 2))
 552                                                    (match-end 2)))))
 553               (goto-char (match-end 0)))
 554              ((looking-at "~")
 555               (forward-char 1)
 556               (setq tilde (read (current-buffer))
 557                     type (car tilde)
 558                     value (cadr tilde))
 559               (cond
 560                ((memq type '(pad pad-left))
 561                 (setq pad-width value))
 562                ((eq type 'pad-right)
 563                 (setq pad-width (- value)))
 564                ((memq type '(max-right max))
 565                 (setq max-width value))
 566                ((eq type 'max-left)
 567                 (setq max-width (- value)))
 568                ((memq type '(cut cut-left))
 569                 (setq cut-width value))
 570                ((eq type 'cut-right)
 571                 (setq cut-width (- value)))
 572                ((eq type 'ignore)
 573                 (setq ignore-value
 574                       (if (stringp value) value (format "%s" value))))
 575                ((eq type 'form)
 576                 (setq tilde-form value))
 577                (t
 578                 (error "Unknown tilde type: %s" tilde)))
 579               t)
 580              (t
 581               nil)))
 582         (cond
 583          ;; User-defined spec -- find the spec name.
 584          ((eq (setq spec (char-after)) ?u)
 585           (forward-char 1)
 586           (when (and (eq (setq user-defined (char-after)) ?&)
 587                      (looking-at "&\\([^;]+\\);"))
 588             (setq user-defined (match-string 1))
 589             (goto-char (match-end 1))))
 590          ;; extended spec
 591          ((and (eq spec ?&) (looking-at "&\\([^;]+\\);"))
 592           (setq extended-spec (intern (match-string 1)))
 593           (goto-char (match-end 1))))
 594         (forward-char 1)
 595         (delete-region spec-beg (point))
 596
 597         ;; Now we have all the relevant data on this spec, so
 598         ;; we start doing stuff.
 599         (insert "%")
 600         (if (eq spec ?%)
 601             ;; "%%" just results in a "%".
 602             (insert "%")
 603           (cond
 604            ;; Do tilde forms.
 605            ((eq spec ?@)
 606             (setq elem (list tilde-form ?s)))
 607            ;; Treat user defined format specifiers specially.
 608            (user-defined
 609             (setq elem
 610                   (list
 611                    (list (intern (format
 612                                   (if (stringp user-defined)
 613                                       "gnus-user-format-function-%s"
 614                                     "gnus-user-format-function-%c")
 615                                   user-defined))
 616                          'gnus-tmp-header)
 617                    ?s)))
 618            ;; Find the specification from `spec-alist'.
 619            ((setq elem (cdr (assq (or extended-spec spec) spec-alist))))
 620            ;; We used to use "%l" for displaying the grouplens score.
 621            ((eq spec ?l)
 622             (setq elem '("" ?s)))
 623            (t
 624             (setq elem '("*" ?s))))
 625           (setq elem-type (cadr elem))
 626           ;; Insert the new format elements.
 627           (when (and pad-width
 628                      (not (and (featurep 'xemacs)
 629                                gnus-use-correct-string-widths)))
 630             (insert (number-to-string pad-width)))
 631           ;; Create the form to be evalled.
 632           (if (or max-width cut-width ignore-value
 633                   (and (featurep 'xemacs)
 634                        gnus-use-correct-string-widths))
 635               (progn
 636                 (insert ?s)
 637                 (let ((el (car elem)))
 638                   (cond ((= (cadr elem) ?c)
 639                          (setq el (list 'char-to-string el)))
 640                         ((= (cadr elem) ?d)
 641                          (setq el (list 'int-to-string el))))
 642                   (when ignore-value
 643                     (setq el (gnus-tilde-ignore-form el ignore-value)))
 644                   (when cut-width
 645                     (setq el (gnus-tilde-cut-form el cut-width)))
 646                   (when max-width
 647                     (setq el (gnus-tilde-max-form el max-width)))
 648                   (when pad-width
 649                     (setq el (gnus-pad-form el pad-width)))
 650                   (push el flist)))
 651             (insert elem-type)
 652             (push (car elem) flist))))
 653       (setq fstring (buffer-substring-no-properties (point-min) (point-max))))
 654
 655     ;; Do some postprocessing to increase efficiency.
 656     (setq
 657      result
 658      (cond
 659       ;; Emptiness.
 660       ((string= fstring "")
 661        nil)
 662       ;; Not a format string.
 663       ((not (string-match "%" fstring))
 664        (list fstring))
 665       ;; A format string with just a single string spec.
 666       ((string= fstring "%s")
 667        (list (car flist)))
 668       ;; A single character.
 669       ((string= fstring "%c")
 670        (list (car flist)))
 671       ;; A single number.
 672       ((string= fstring "%d")
 673        (setq dontinsert t)
 674        (if insert
 675            `(insert (int-to-string ,(car flist)))
 676          (list `(int-to-string ,(car flist)))))
 677       ;; Just lots of chars and strings.
 678       ((string-match "\\`\\(%[cs]\\)+\\'" fstring)
 679        (nreverse flist))
 680       ;; A single string spec at the beginning of the spec.
 681       ((string-match "\\`%[sc][^%]+\\'" fstring)
 682        (list (car flist) (substring fstring 2)))
 683       ;; A single string spec in the middle of the spec.
 684       ((string-match "\\`\\([^%]+\\)%[sc]\\([^%]+\\)\\'" fstring)
 685        (list (match-string 1 fstring) (car flist) (match-string 2 fstring)))
 686       ;; A single string spec in the end of the spec.
 687       ((string-match "\\`\\([^%]+\\)%[sc]\\'" fstring)
 688        (list (match-string 1 fstring) (car flist)))
 689       ;; Only string (and %) specs (XEmacs only!)
 690       ((and (featurep 'xemacs)
 691             gnus-make-format-preserve-properties
 692             (string-match
 693              "\\`\\([^%]*\\(%%\\|%-?\\([1-9][0-9]*\\)?s\\)\\)*[^%]*\\'"
 694              fstring))
 695        (list (cons 'gnus-xmas-format (cons fstring (nreverse flist)))))
 696       ;; A more complex spec.
 697       (t
 698        (list (cons 'format (cons fstring (nreverse flist)))))))
 699
 700     (if insert
 701         (when result
 702           (if dontinsert
 703               result
 704             (cons 'insert result)))
 705       (cond ((stringp result)
 706              result)
 707             ((consp result)
 708              (cons 'concat result))
 709             (t "")))))
 710
 711 (defun gnus-eval-format (format &optional alist props)
 712   "Eval the format variable FORMAT, using ALIST.
 713 If PROPS, insert the result."
 714   (let ((form (gnus-parse-format format alist props)))
 715     (if props
 716         (gnus-add-text-properties (point) (progn (eval form) (point)) props)
 717       (eval form))))
 718
 719 (defun gnus-set-format (type &optional insertable)
 720   (set (intern (format "gnus-%s-line-format-spec" type))
 721        (gnus-parse-format
 722         (symbol-value (intern (format "gnus-%s-line-format" type)))
 723         (symbol-value (intern (format "gnus-%s-line-format-alist" type)))
 724         insertable)))
 725
 726 (provide 'gnus-spec)
 727
 728 ;; Local Variables:
 729 ;; coding: iso-8859-1
 730 ;; End:
 731
 732 ;;; gnus-spec.el ends here