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e8af40ee 1;;; ewoc.el --- utility to maintain a view of a list of objects in a buffer
5b467bf4 2
e7cff550 3;; Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000 Free Software Foundation
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4
5;; Author: Per Cederqvist <ceder@lysator.liu.se>
6;; Inge Wallin <inge@lysator.liu.se>
7;; Maintainer: monnier@gnu.org
8;; Created: 3 Aug 1992
9;; Keywords: extensions, lisp
10
11;; This file is part of GNU Emacs.
12
13;; GNU Emacs is free software; you can redistribute it and/or modify
14;; it under the terms of the GNU General Public License as published by
15;; the Free Software Foundation; either version 2, or (at your option)
16;; any later version.
17
18;; GNU Emacs is distributed in the hope that it will be useful,
19;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21;; GNU General Public License for more details.
22
23;; You should have received a copy of the GNU General Public License
24;; along with GNU Emacs; see the file COPYING. If not, write to the
25;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
26;; Boston, MA 02111-1307, USA.
27
28;;; Commentary:
29
30;; Ewoc Was Once Cookie
31;; But now it's Emacs' Widget for Object Collections
32
33;; As the name implies this derives from the `cookie' package (part
10c471e6 34;; of Elib). The changes are pervasive though mostly superficial:
5b467bf4 35
10c471e6 36;; - uses CL (and its `defstruct')
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37;; - separate from Elib.
38;; - uses its own version of a doubly-linked list which allows us
39;; to merge the elib-wrapper and the elib-node structures into ewoc-node
40;; - dropping functions not used by PCL-CVS (the only client of ewoc at the
41;; time of writing)
42;; - removing unused arguments
43;; - renaming:
44;; elib-node ==> ewoc--node
45;; collection ==> ewoc
46;; tin ==> ewoc--node
47;; cookie ==> data or element or elem
48
49;; Introduction
50;; ============
51;;
52;; Ewoc is a package that implements a connection between an
53;; dll (a doubly linked list) and the contents of a buffer.
54;; Possible uses are dired (have all files in a list, and show them),
55;; buffer-list, kom-prioritize (in the LysKOM elisp client) and
56;; others. pcl-cvs.el uses ewoc.el.
57;;
58;; Ewoc can be considered as the `view' part of a model-view-controller.
59;;
60;; A `element' can be any lisp object. When you use the ewoc
61;; package you specify a pretty-printer, a function that inserts
62;; a printable representation of the element in the buffer. (The
63;; pretty-printer should use "insert" and not
64;; "insert-before-markers").
65;;
66;; A `ewoc' consists of a doubly linked list of elements, a
67;; header, a footer and a pretty-printer. It is displayed at a
68;; certain point in a certain buffer. (The buffer and point are
69;; fixed when the ewoc is created). The header and the footer
70;; are constant strings. They appear before and after the elements.
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71;;
72;; Ewoc does not affect the mode of the buffer in any way. It
73;; merely makes it easy to connect an underlying data representation
74;; to the buffer contents.
75;;
76;; A `ewoc--node' is an object that contains one element. There are
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77;; functions in this package that given an ewoc--node extract the data, or
78;; give the next or previous ewoc--node. (All ewoc--nodes are linked together
79;; in a doubly linked list. The `previous' ewoc--node is the one that appears
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80;; before the other in the buffer.) You should not do anything with
81;; an ewoc--node except pass it to the functions in this package.
82;;
83;; An ewoc is a very dynamic thing. You can easily add or delete elements.
84;; You can apply a function to all elements in an ewoc, etc, etc.
85;;
86;; Remember that an element can be anything. Your imagination is the
87;; limit! It is even possible to have another ewoc as an
88;; element. In that way some kind of tree hierarchy can be created.
89;;
90;; Full documentation will, God willing, soon be available in a
91;; Texinfo manual.
92
93;; In the mean time `grep '^(.*ewoc-[^-]' emacs-lisp/ewoc.el' can help
94;; you find all the exported functions:
a1506d29 95;;
cb3430a1 96;; (defun ewoc-create (pretty-printer &optional header footer)
5b467bf4 97;; (defalias 'ewoc-data 'ewoc--node-data)
10c471e6 98;; (defun ewoc-location (node)
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99;; (defun ewoc-enter-first (ewoc data)
100;; (defun ewoc-enter-last (ewoc data)
101;; (defun ewoc-enter-after (ewoc node data)
102;; (defun ewoc-enter-before (ewoc node data)
103;; (defun ewoc-next (ewoc node)
104;; (defun ewoc-prev (ewoc node)
105;; (defun ewoc-nth (ewoc n)
106;; (defun ewoc-map (map-function ewoc &rest args)
107;; (defun ewoc-filter (ewoc predicate &rest args)
44946a4c 108;; (defun ewoc-locate (ewoc &optional pos guess)
5b467bf4 109;; (defun ewoc-invalidate (ewoc &rest nodes)
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110;; (defun ewoc-goto-prev (ewoc arg)
111;; (defun ewoc-goto-next (ewoc arg)
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112;; (defun ewoc-goto-node (ewoc node)
113;; (defun ewoc-refresh (ewoc)
114;; (defun ewoc-collect (ewoc predicate &rest args)
115;; (defun ewoc-buffer (ewoc)
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116;; (defun ewoc-get-hf (ewoc)
117;; (defun ewoc-set-hf (ewoc header footer)
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118
119;; Coding conventions
120;; ==================
121;;
122;; All functions of course start with `ewoc'. Functions and macros
123;; starting with the prefix `ewoc--' are meant for internal use,
124;; while those starting with `ewoc-' are exported for public use.
125;; There are currently no global or buffer-local variables used.
126
127
128;;; Code:
129
130(eval-when-compile (require 'cl)) ;because of CL compiler macros
131
132;; The doubly linked list is implemented as a circular list
133;; with a dummy node first and last. The dummy node is used as
134;; "the dll" (or rather is the dll handle passed around).
135
136(defstruct (ewoc--node
137 (:type vector) ;required for ewoc--node-branch hack
138 (:constructor ewoc--node-create (start-marker data)))
139 left right data start-marker)
140
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141(defalias 'ewoc--node-branch 'aref
142 "Get the left (CHILD=0) or right (CHILD=1) child of the NODE.
143
144\(fn NODE CHILD)")
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145
146(defun ewoc--dll-create ()
147 "Create an empty doubly linked list."
148 (let ((dummy-node (ewoc--node-create 'DL-LIST 'DL-LIST)))
149 (setf (ewoc--node-right dummy-node) dummy-node)
150 (setf (ewoc--node-left dummy-node) dummy-node)
151 dummy-node))
152
153(defun ewoc--node-enter-before (node elemnode)
154 "Insert ELEMNODE before NODE in a DLL."
155 (assert (and (null (ewoc--node-left elemnode)) (null (ewoc--node-right elemnode))))
156 (setf (ewoc--node-left elemnode) (ewoc--node-left node))
157 (setf (ewoc--node-right elemnode) node)
158 (setf (ewoc--node-right (ewoc--node-left node)) elemnode)
159 (setf (ewoc--node-left node) elemnode))
160
161(defun ewoc--node-enter-first (dll node)
162 "Add a free floating NODE first in DLL."
163 (ewoc--node-enter-before (ewoc--node-right dll) node))
164
165(defun ewoc--node-enter-last (dll node)
166 "Add a free floating NODE last in DLL."
167 (ewoc--node-enter-before dll node))
168
169(defun ewoc--node-next (dll node)
170 "Return the node after NODE, or nil if NODE is the last node."
171 (unless (eq (ewoc--node-right node) dll) (ewoc--node-right node)))
172
173(defun ewoc--node-prev (dll node)
174 "Return the node before NODE, or nil if NODE is the first node."
175 (unless (eq (ewoc--node-left node) dll) (ewoc--node-left node)))
176
177(defun ewoc--node-delete (node)
178 "Unbind NODE from its doubly linked list and return it."
179 ;; This is a no-op when applied to the dummy node. This will return
180 ;; nil if applied to the dummy node since it always contains nil.
181 (setf (ewoc--node-right (ewoc--node-left node)) (ewoc--node-right node))
182 (setf (ewoc--node-left (ewoc--node-right node)) (ewoc--node-left node))
183 (setf (ewoc--node-left node) nil)
184 (setf (ewoc--node-right node) nil)
185 node)
186
187(defun ewoc--node-nth (dll n)
188 "Return the Nth node from the doubly linked list DLL.
189N counts from zero. If DLL is not that long, nil is returned.
190If N is negative, return the -(N+1)th last element.
191Thus, (ewoc--node-nth dll 0) returns the first node,
192and (ewoc--node-nth dll -1) returns the last node."
193 ;; Branch 0 ("follow left pointer") is used when n is negative.
194 ;; Branch 1 ("follow right pointer") is used otherwise.
195 (let* ((branch (if (< n 0) 0 1))
196 (node (ewoc--node-branch dll branch)))
197 (if (< n 0) (setq n (- -1 n)))
198 (while (and (not (eq dll node)) (> n 0))
199 (setq node (ewoc--node-branch node branch))
200 (setq n (1- n)))
201 (unless (eq dll node) node)))
202
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203(defun ewoc-location (node)
204 "Return the start location of NODE."
205 (ewoc--node-start-marker node))
206
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207\f
208;;; The ewoc data type
209
210(defstruct (ewoc
211 (:constructor nil)
212 (:constructor ewoc--create
213 (buffer pretty-printer header footer dll))
214 (:conc-name ewoc--))
215 buffer pretty-printer header footer dll last-node)
216
217(defmacro ewoc--set-buffer-bind-dll-let* (ewoc varlist &rest forms)
218 "Execute FORMS with ewoc--buffer selected as current buffer,
219dll bound to ewoc--dll, and VARLIST bound as in a let*.
220dll will be bound when VARLIST is initialized, but the current
221buffer will *not* have been changed.
222Return value of last form in FORMS."
223 (let ((old-buffer (make-symbol "old-buffer"))
224 (hnd (make-symbol "ewoc")))
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225 `(let* ((,old-buffer (current-buffer))
226 (,hnd ,ewoc)
227 (dll (ewoc--dll ,hnd))
228 ,@varlist)
229 (set-buffer (ewoc--buffer ,hnd))
230 (unwind-protect
231 (progn ,@forms)
232 (set-buffer ,old-buffer)))))
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233
234(defmacro ewoc--set-buffer-bind-dll (ewoc &rest forms)
235 `(ewoc--set-buffer-bind-dll-let* ,ewoc nil ,@forms))
236
237(defsubst ewoc--filter-hf-nodes (ewoc node)
238 "Evaluate NODE once and return it.
239BUT if it is the header or the footer in EWOC return nil instead."
240 (unless (or (eq node (ewoc--header ewoc))
241 (eq node (ewoc--footer ewoc)))
242 node))
243
244
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245(defun ewoc--create-node (data pretty-printer pos)
246 "Call PRETTY-PRINTER with point set at POS in current buffer.
247Remember the start position. Create a wrapper containing that
248start position and the element DATA."
249 (save-excursion
250 ;; Remember the position as a number so that it doesn't move
251 ;; when we insert the string.
252 (when (markerp pos) (setq pos (marker-position pos)))
253 (goto-char pos)
254 (let ((inhibit-read-only t))
255 ;; Insert the trailing newline using insert-before-markers
256 ;; so that the start position for the next element is updated.
257 (insert-before-markers ?\n)
258 ;; Move back, and call the pretty-printer.
259 (backward-char 1)
260 (funcall pretty-printer data)
261 (ewoc--node-create (copy-marker pos) data))))
262
263
264(defun ewoc--delete-node-internal (ewoc node)
265 "Delete a data string from EWOC.
266Can not be used on the footer. Returns the wrapper that is deleted.
267The start-marker in the wrapper is set to nil, so that it doesn't
268consume any more resources."
269 (let ((dll (ewoc--dll ewoc))
270 (inhibit-read-only t))
271 ;; If we are about to delete the node pointed at by last-node,
272 ;; set last-node to nil.
273 (if (eq (ewoc--last-node ewoc) node)
274 (setf (ewoc--last-node ewoc) nil))
275
276 (delete-region (ewoc--node-start-marker node)
277 (ewoc--node-start-marker (ewoc--node-next dll node)))
278 (set-marker (ewoc--node-start-marker node) nil)
279 ;; Delete the node, and return the wrapper.
280 (ewoc--node-delete node)))
281
282
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283(defun ewoc--refresh-node (pp node)
284 "Redisplay the element represented by NODE using the pretty-printer PP."
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285 (let ((inhibit-read-only t))
286 (save-excursion
287 ;; First, remove the string from the buffer:
288 (delete-region (ewoc--node-start-marker node)
289 (1- (marker-position
cb3430a1 290 (ewoc--node-start-marker (ewoc--node-right node)))))
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291 ;; Calculate and insert the string.
292 (goto-char (ewoc--node-start-marker node))
cb3430a1 293 (funcall pp (ewoc--node-data node)))))
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294\f
295;;; ===========================================================================
296;;; Public members of the Ewoc package
297
298
cb3430a1 299(defun ewoc-create (pretty-printer &optional header footer)
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300 "Create an empty ewoc.
301
cb3430a1 302The ewoc will be inserted in the current buffer at the current position.
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303
304PRETTY-PRINTER should be a function that takes one argument, an
305element, and inserts a string representing it in the buffer (at
306point). The string PRETTY-PRINTER inserts may be empty or span
307several linse. A trailing newline will always be inserted
308automatically. The PRETTY-PRINTER should use insert, and not
309insert-before-markers.
310
311Optional third argument HEADER is a string that will always be
312present at the top of the ewoc. HEADER should end with a
313newline. Optionaly fourth argument FOOTER is similar, and will
cb3430a1 314be inserted at the bottom of the ewoc."
5b467bf4 315 (let ((new-ewoc
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316 (ewoc--create (current-buffer)
317 pretty-printer nil nil (ewoc--dll-create)))
318 (pos (point)))
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319 (ewoc--set-buffer-bind-dll new-ewoc
320 ;; Set default values
321 (unless header (setq header ""))
322 (unless footer (setq footer ""))
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323 (setf (ewoc--node-start-marker dll) (copy-marker pos))
324 (let ((foot (ewoc--create-node footer (lambda (x) (insert footer)) pos))
325 (head (ewoc--create-node header (lambda (x) (insert header)) pos)))
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326 (ewoc--node-enter-first dll head)
327 (ewoc--node-enter-last dll foot)
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328 (setf (ewoc--header new-ewoc) head)
329 (setf (ewoc--footer new-ewoc) foot)))
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330 ;; Return the ewoc
331 new-ewoc))
332
333(defalias 'ewoc-data 'ewoc--node-data)
334
335(defun ewoc-enter-first (ewoc data)
336 "Enter DATA first in EWOC."
337 (ewoc--set-buffer-bind-dll ewoc
338 (ewoc-enter-after ewoc (ewoc--node-nth dll 0) data)))
339
340(defun ewoc-enter-last (ewoc data)
341 "Enter DATA last in EWOC."
342 (ewoc--set-buffer-bind-dll ewoc
343 (ewoc-enter-before ewoc (ewoc--node-nth dll -1) data)))
344
345
346(defun ewoc-enter-after (ewoc node data)
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347 "Enter a new element DATA after NODE in EWOC.
348Returns the new NODE."
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349 (ewoc--set-buffer-bind-dll ewoc
350 (ewoc-enter-before ewoc (ewoc--node-next dll node) data)))
351
352(defun ewoc-enter-before (ewoc node data)
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353 "Enter a new element DATA before NODE in EWOC.
354Returns the new NODE."
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355 (ewoc--set-buffer-bind-dll ewoc
356 (ewoc--node-enter-before
357 node
358 (ewoc--create-node
359 data
360 (ewoc--pretty-printer ewoc)
361 (ewoc--node-start-marker node)))))
362
363(defun ewoc-next (ewoc node)
364 "Get the next node.
365Returns nil if NODE is nil or the last element."
366 (when node
367 (ewoc--filter-hf-nodes
368 ewoc (ewoc--node-next (ewoc--dll ewoc) node))))
369
370(defun ewoc-prev (ewoc node)
371 "Get the previous node.
372Returns nil if NODE is nil or the first element."
373 (when node
374 (ewoc--filter-hf-nodes
375 ewoc
376 (ewoc--node-prev (ewoc--dll ewoc) node))))
377
378
379(defun ewoc-nth (ewoc n)
380 "Return the Nth node.
f0529b5b 381N counts from zero. Return nil if there is less than N elements.
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382If N is negative, return the -(N+1)th last element.
383Thus, (ewoc-nth dll 0) returns the first node,
384and (ewoc-nth dll -1) returns the last node.
385Use `ewoc--node-data' to extract the data from the node."
386 ;; Skip the header (or footer, if n is negative).
387 (setq n (if (< n 0) (1- n) (1+ n)))
388 (ewoc--filter-hf-nodes ewoc
389 (ewoc--node-nth (ewoc--dll ewoc) n)))
390
391(defun ewoc-map (map-function ewoc &rest args)
392 "Apply MAP-FUNCTION to all elements in EWOC.
393MAP-FUNCTION is applied to the first element first.
394If MAP-FUNCTION returns non-nil the element will be refreshed (its
395pretty-printer will be called once again).
396
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397Note that the buffer for EWOC will be current buffer when MAP-FUNCTION
398is called. MAP-FUNCTION must restore the current buffer to BUFFER before
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399it returns, if it changes it.
400
401If more than two arguments are given, the remaining
402arguments will be passed to MAP-FUNCTION."
403 (ewoc--set-buffer-bind-dll-let* ewoc
404 ((footer (ewoc--footer ewoc))
405 (node (ewoc--node-nth dll 1)))
406 (while (not (eq node footer))
407 (if (apply map-function (ewoc--node-data node) args)
cb3430a1 408 (ewoc--refresh-node (ewoc--pretty-printer ewoc) node))
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409 (setq node (ewoc--node-next dll node)))))
410
411(defun ewoc-filter (ewoc predicate &rest args)
412 "Remove all elements in EWOC for which PREDICATE returns nil.
a1506d29 413Note that the buffer for EWOC will be current-buffer when PREDICATE
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414is called. PREDICATE must restore the current buffer before it returns
415if it changes it.
416The PREDICATE is called with the element as its first argument. If any
417ARGS are given they will be passed to the PREDICATE."
418 (ewoc--set-buffer-bind-dll-let* ewoc
419 ((node (ewoc--node-nth dll 1))
420 (footer (ewoc--footer ewoc))
421 (next nil))
422 (while (not (eq node footer))
423 (setq next (ewoc--node-next dll node))
424 (unless (apply predicate (ewoc--node-data node) args)
425 (ewoc--delete-node-internal ewoc node))
426 (setq node next))))
427
44946a4c 428(defun ewoc-locate (ewoc &optional pos guess)
5b467bf4 429 "Return the node that POS (a buffer position) is within.
44946a4c 430POS may be a marker or an integer. It defaults to point.
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431GUESS should be a node that it is likely that POS is near.
432
433If POS points before the first element, the first node is returned.
434If POS points after the last element, the last node is returned.
435If the EWOC is empty, nil is returned."
44946a4c 436 (unless pos (setq pos (point)))
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437 (ewoc--set-buffer-bind-dll-let* ewoc
438 ((footer (ewoc--footer ewoc)))
439
440 (cond
441 ;; Nothing present?
442 ((eq (ewoc--node-nth dll 1) (ewoc--node-nth dll -1))
443 nil)
444
445 ;; Before second elem?
446 ((< pos (ewoc--node-start-marker (ewoc--node-nth dll 2)))
447 (ewoc--node-nth dll 1))
448
449 ;; After one-before-last elem?
450 ((>= pos (ewoc--node-start-marker (ewoc--node-nth dll -2)))
451 (ewoc--node-nth dll -2))
452
453 ;; We now know that pos is within a elem.
454 (t
455 ;; Make an educated guess about which of the three known
456 ;; node'es (the first, the last, or GUESS) is nearest.
457 (let* ((best-guess (ewoc--node-nth dll 1))
458 (distance (abs (- pos (ewoc--node-start-marker best-guess)))))
459 (when guess
460 (let ((d (abs (- pos (ewoc--node-start-marker guess)))))
461 (when (< d distance)
462 (setq distance d)
463 (setq best-guess guess))))
464
465 (let* ((g (ewoc--node-nth dll -1)) ;Check the last elem
466 (d (abs (- pos (ewoc--node-start-marker g)))))
467 (when (< d distance)
468 (setq distance d)
469 (setq best-guess g)))
470
471 (when (ewoc--last-node ewoc) ;Check "previous".
472 (let* ((g (ewoc--last-node ewoc))
473 (d (abs (- pos (ewoc--node-start-marker g)))))
474 (when (< d distance)
475 (setq distance d)
476 (setq best-guess g))))
477
478 ;; best-guess is now a "best guess".
479 ;; Find the correct node. First determine in which direction
480 ;; it lies, and then move in that direction until it is found.
a1506d29 481
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482 (cond
483 ;; Is pos after the guess?
484 ((>= pos
485 (ewoc--node-start-marker best-guess))
486 ;; Loop until we are exactly one node too far down...
487 (while (>= pos (ewoc--node-start-marker best-guess))
488 (setq best-guess (ewoc--node-next dll best-guess)))
489 ;; ...and return the previous node.
490 (ewoc--node-prev dll best-guess))
491
492 ;; Pos is before best-guess
493 (t
494 (while (< pos (ewoc--node-start-marker best-guess))
495 (setq best-guess (ewoc--node-prev dll best-guess)))
496 best-guess)))))))
497
498(defun ewoc-invalidate (ewoc &rest nodes)
499 "Refresh some elements.
500The pretty-printer that for EWOC will be called for all NODES."
501 (ewoc--set-buffer-bind-dll ewoc
502 (dolist (node nodes)
cb3430a1 503 (ewoc--refresh-node (ewoc--pretty-printer ewoc) node))))
5b467bf4 504
44946a4c 505(defun ewoc-goto-prev (ewoc arg)
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506 "Move point to the ARGth previous element.
507Don't move if we are at the first element, or if EWOC is empty.
508Returns the node we moved to."
509 (ewoc--set-buffer-bind-dll-let* ewoc
6d84ac85 510 ((node (ewoc-locate ewoc (point))))
5b467bf4 511 (when node
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512 ;; If we were past the last element, first jump to it.
513 (when (>= (point) (ewoc--node-start-marker (ewoc--node-right node)))
514 (setq arg (1- arg)))
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515 (while (and node (> arg 0))
516 (setq arg (1- arg))
517 (setq node (ewoc--node-prev dll node)))
518 ;; Never step above the first element.
519 (unless (ewoc--filter-hf-nodes ewoc node)
520 (setq node (ewoc--node-nth dll 1)))
521 (ewoc-goto-node ewoc node))))
522
44946a4c 523(defun ewoc-goto-next (ewoc arg)
5b467bf4 524 "Move point to the ARGth next element.
44946a4c 525Returns the node (or nil if we just passed the last node)."
5b467bf4 526 (ewoc--set-buffer-bind-dll-let* ewoc
6d84ac85 527 ((node (ewoc-locate ewoc (point))))
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528 (while (and node (> arg 0))
529 (setq arg (1- arg))
530 (setq node (ewoc--node-next dll node)))
531 ;; Never step below the first element.
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532 ;; (unless (ewoc--filter-hf-nodes ewoc node)
533 ;; (setq node (ewoc--node-nth dll -2)))
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534 (ewoc-goto-node ewoc node)))
535
536(defun ewoc-goto-node (ewoc node)
537 "Move point to NODE."
538 (ewoc--set-buffer-bind-dll ewoc
539 (goto-char (ewoc--node-start-marker node))
540 (if goal-column (move-to-column goal-column))
541 (setf (ewoc--last-node ewoc) node)))
542
543(defun ewoc-refresh (ewoc)
544 "Refresh all data in EWOC.
545The pretty-printer that was specified when the EWOC was created
546will be called for all elements in EWOC.
547Note that `ewoc-invalidate' is more efficient if only a small
548number of elements needs to be refreshed."
549 (ewoc--set-buffer-bind-dll-let* ewoc
cb3430a1 550 ((footer (ewoc--footer ewoc)))
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551 (let ((inhibit-read-only t))
552 (delete-region (ewoc--node-start-marker (ewoc--node-nth dll 1))
553 (ewoc--node-start-marker footer))
554 (goto-char (ewoc--node-start-marker footer))
555 (let ((node (ewoc--node-nth dll 1)))
556 (while (not (eq node footer))
557 (set-marker (ewoc--node-start-marker node) (point))
558 (funcall (ewoc--pretty-printer ewoc)
559 (ewoc--node-data node))
560 (insert "\n")
561 (setq node (ewoc--node-next dll node)))))
562 (set-marker (ewoc--node-start-marker footer) (point))))
563
564(defun ewoc-collect (ewoc predicate &rest args)
565 "Select elements from EWOC using PREDICATE.
566Return a list of all selected data elements.
567PREDICATE is a function that takes a data element as its first argument.
568The elements on the returned list will appear in the same order as in
569the buffer. You should not rely on in which order PREDICATE is
570called.
571Note that the buffer the EWOC is displayed in is current-buffer
572when PREDICATE is called. If PREDICATE must restore current-buffer if
573it changes it.
574If more than two arguments are given the
575remaining arguments will be passed to PREDICATE."
576 (ewoc--set-buffer-bind-dll-let* ewoc
577 ((header (ewoc--header ewoc))
578 (node (ewoc--node-nth dll -2))
579 result)
580 (while (not (eq node header))
581 (if (apply predicate (ewoc--node-data node) args)
582 (push (ewoc--node-data node) result))
583 (setq node (ewoc--node-prev dll node)))
6d84ac85 584 (nreverse result)))
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585
586(defun ewoc-buffer (ewoc)
587 "Return the buffer that is associated with EWOC.
588Returns nil if the buffer has been deleted."
589 (let ((buf (ewoc--buffer ewoc)))
590 (when (buffer-name buf) buf)))
591
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592(defun ewoc-get-hf (ewoc)
593 "Return a cons cell containing the (HEADER . FOOTER) of EWOC."
594 (cons (ewoc--node-data (ewoc--header ewoc))
595 (ewoc--node-data (ewoc--footer ewoc))))
596
597(defun ewoc-set-hf (ewoc header footer)
598 "Set the HEADER and FOOTER of EWOC."
599 (setf (ewoc--node-data (ewoc--header ewoc)) header)
600 (setf (ewoc--node-data (ewoc--footer ewoc)) footer)
601 (ewoc--refresh-node (lambda (x) (insert header)) (ewoc--header ewoc))
602 (ewoc--refresh-node (lambda (x) (insert footer)) (ewoc--footer ewoc)))
603
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604\f
605(provide 'ewoc)
606
607;;; Local Variables:
608;;; eval: (put 'ewoc--set-buffer-bind-dll 'lisp-indent-hook 1)
609;;; eval: (put 'ewoc--set-buffer-bind-dll-let* 'lisp-indent-hook 2)
610;;; End:
611
ab5796a9 612;;; arch-tag: d78915b9-9a07-44bf-aac6-04a1fc1bd6d4
5b467bf4 613;;; ewoc.el ends here