Jak sprawić, by cofanie drzewa było liniowe - cofanie drzewa cofania / ponawiania

Przy undo-tree-undo/redosukcesywnym uruchamianiu polecenia czynności są cofane / powtarzane na podstawie bieżącej aktywnej gałęzi. Chociaż po drodze użytkownik otrzymuje komunikat punktu rozgałęzienia, poprzednie gałęzie są ignorowane, chyba że użytkownik ręcznie wybierze inną gałąź.

Rozumiem, że mogę otworzyć wizualizator i wybrać inną gałąź, jednak bardzo przydatne byłoby po prostu przytrzymanie klawisza cofania / ponawiania i obserwowanie, jak wszystko dzieje się w dokładnie odwrotnej kolejności. Najlepiej byłoby, gdyby działało to niezależnie od tego, czy visualizerbufor jest otwarty - tj. Programowo oblicza kolejność od początku do końca i od początku do końca.

P : Zasadniczo jest to żądanie rozszerzenia funkcji, undo-treeaby umożliwić liniowe kolejne cofanie / ponawianie, niezależnie od tego, czy bufor wizualizatora jest otwarty. [Nowe funkcje i alternatywne skróty klawiaturowe dla tej nowej funkcji są z pewnością dopuszczalne.]

Poniżej znajduje się prototypowa implementacja przybliżenia tego, co chcesz. Wykorzystuje to fakt, że nowe gałęzie w cofniętym drzewie są dodawane po lewej stronie bieżącego węzła.

Powiązana C-M-_jest sekwencja klawiszy, z undo-tree-walkktórą przechodzi prawa górna część drzewa cofania, zaczynając od bieżącego węzła.

Zachowanie różni się od tego, czego chcesz, jeśli aktywna gałąź jakiegoś poddrzewa po prawej stronie bieżącego węzła nie jest gałęzią najbardziej wysuniętą w lewo w tym poddrzewie.

Możesz wejść w taki stan, wykonując niebanalne sekwencje cofania / powtarzania.

Po prostu spróbuj sam, aby sprawdzić, czy to wystarczy do twojej aplikacji.

(defvar-local undo-tree-walk
  "Possible values:
nil: not in undo/redo-chain
undo: traversing undo tree upwards
redo: traversing undo tree downwards
")

(setq undo-tree-walk nil)

(defun undo-tree-walk ()
  "Walk the right-upper part of the undo-tree starting at the current node."
  (interactive)
  (when (eq buffer-undo-list t)
    (user-error "No undo information."))
  (unless undo-tree-mode
    (user-error "`undo-tree-walk' should only be used with `undo-tree-mode'."))
  (undo-list-transfer-to-tree)
  (set-transient-map undo-tree-walk-map t #'undo-tree-walk-off)
  (let ((num-branches (undo-tree-num-branches)))
    (cond
     ((= num-branches 0) ; arrived at leaf
      (setq undo-tree-walk 'undo))
     ((> num-branches 1) ; 
      (let ((branch (undo-tree-node-branch (undo-tree-current buffer-undo-tree))))
    (setf (undo-tree-node-branch (undo-tree-current buffer-undo-tree))
          (if (>= (1+ branch) (undo-tree-num-branches))
          (progn
            (setq undo-tree-walk 'undo)
            (1- (undo-tree-num-branches)))
        (setq undo-tree-walk 'redo)
        (1+ branch))))
      ;; no state change for (= num-branches 1)
      )
     ))
  (case undo-tree-walk
   (undo
    (undo-tree-undo-1))
   (redo
    (undo-tree-redo-1))
   (t
    (setq undo-tree-walk 'undo)
    (undo-tree-undo-1)))
  (let ((curbuf (current-buffer)))
    (undo-tree-visualize)
    (switch-to-buffer-other-window curbuf)))

(defun undo-tree-walk-off ()
  "Switch `undo-tree-walk' off."
  (setq undo-tree-walk nil))

(defvar undo-tree-walk-map
  (make-sparse-keymap)
  "Keymap active while `undo-tree-walk'.")

(define-key undo-tree-walk-map (kbd "C-M-_") #'undo-tree-walk)

(global-set-key (kbd "C-M-_") #'undo-tree-walk)

Zauważ, że dodałem undo-tree-visualizena końcu, undo-tree-walkaby wyświetlić konsekwencje chodzenia po cofniętym drzewie undo-tree-walk. Zmodyfikuj kod według własnych upodobań.

Zauważ też, że musiałem wybrać to najprostsze przybliżenie rozwiązania twojego problemu z powodu ograniczeń czasowych.

Specjalne podziękowania dla @Tobias za napisanie funkcji do zlokalizowania następnego / poprzedniego znacznika czasu w historii cofania / ponawiania: https://emacs.stackexchange.com/a/32415/2287 ; a także w celu napisania szeregu funkcji do skopiowania drzewa cofnięć: https://emacs.stackexchange.com/a/32230/2287 .

Jak niektórzy czytelnicy mogą już wiedzieć, widelce są akceptowane przez MELPA tylko w ekstremalnych okolicznościach. Utworzenie dodatku jest prawdopodobnie wykonalne, ale nie wydaje się praktyczne, biorąc pod uwagę liczbę zmian dokonanych przez @lawlist - w tym między innymi dodanie elementów do wektorów struktury danych i zmianę nazw kilku funkcje / zmienne, które nie były zgodne z undo-tree-...konwencją nazewnictwa prefiksów itp. @lawlist skontaktował się już z oryginalnym autorem (Dr. Cubitt), aby zaoferować tę nową funkcję, a także różne poprawki i ulepszenia błędów.

Jeśli ktoś jest zainteresowany, zachęcamy do skorzystania z tej nowej funkcji. Komentarz zawiera przykładowy formularz zgłoszenia raportu o błędzie, zaczynający się emacs -qna wypadek, gdyby ktoś miał problemy.

Kod źródłowy:   https://github.com/lawlist/undo_tree

Komentarz:

;;; This unofficial modification by @lawlist to the `undo-tree.el` library authored
;;; by Toby Cubitt adds semi-linear undo/redo support and a corresponding visualizer
;;; view accessible with `C-u C-x u` or by using the 3-way toggle with the letter `t`
;;; in the visualization buffer.  This entire library is meant to be a replacement
;;; of the stock version of `undo-tree.el`, which would need to be completely removed
;;; from the `load-path'.  In the visualization buffer, the letters `u` / `r`
;;; or `z` / `Z` are used for semi-linear undo/redo.  In the working buffer,
;;; `super-u` / `super-r` or `super-z`/`super-Z` are used for semi-linear undo/redo.
;;; Semi-linear undo/redo also work in the classic views of the visualization buffer.
;;; All previous keyboard shortcuts remain unchanged.  The mouse can be used to
;;; select semi-linear nodes or branch-point timestamps in the visualization buffer.
;;;
;;; The term `semi-linear` was chosen because the time-line is generally structured
;;; as follows:  When undoing, the movement is in an upward direction from the
;;; leaf to the branch-point and then the previous branch begins undoing from the
;;; leaf.  When redoing, the movement is in a downward direction from the branch-
;;; point to the leaf and then the next branch begins redoing from the branch-point.
;;; It is not a situation where we walk-up and back-down the same branch, or walk-
;;; down and back-up the same branch again.  If that missing feature is useful,
;;; then perhaps it could be implemented someday....
;;;
;;; In a nutshell, the classic version of undo-tree undo/redo limits a user to
;;; the active branch (skipping over inactive branches), unless the user calls
;;; `undo-tree-switch-branch' or `undo-tree-visualize-switch-branch-right' or
;;; `undo-tree-visualize-switch-branch-left' to select an alternative branch.  This
;;; generally means a user must pop-open the visualizer buffer to see what is going
;;; on to make a proper decision.  The new semi-linear feature is essentially
;;; "mindless" where the user can just hold down the forward/reverse button and
;;; go through every node of the tree in chronological order -- i.e., all branches
;;; and nodes are visited in the process (nothing is skipped over).
;;;
;;; The labels in the visualization buffer remain the same:  `o`, `x`, `s`, register.
;;; The branches are labeled consecutively as they are drawn with lowercase letters.
;;; The branch-points are labeled consecutively as they are drawn with uppercase
;;; letters.  The branches coming off of each branch-point are labeled with the nth
;;; numeric position of the branch -- e.g., far left is always nth 0.  The nodes of
;;; each branch are numbered consecutively commencing just after the branch-point.
;;;
;;; The features that are available in `undo-tree.el` version 0.6.6 remain the same;
;;; however, some of the functions have been consolidated and the names have changed.
;;;
;;; `undo-tree-history-save' and `undo-tree-history-restore' support input/output
;;; to/from a string or a file.  The history string/file contains three components:
;;; `buffer-file-name' (if it exists; else `nil`); SHA1 string; the `undo-tree-list'.
;;; Histories created with the unmodified stock version of `undo-tree.el` contained 2
;;; components and those previous versions are no longer supported.  Saving/exporting
;;; excludes all text-properties, yasnippet entries, and multiple-cursors entries.
;;; `read' chokes when encountering #<marker in no buffer> or #<overlay in no buffer>,
;;; that can make their way into the `undo-tree-list' when killing the visualizer
;;; buffer by brute force or when using the yasnippet library.  Those two known
;;; situations have been dealt with programmatically.  However, there are surely
;;; other libraries that use markers and/or overlays that could make their way into
;;; the tree and new ways of dealing with those entries will be required.  If you
;;; encounter an error message when performing `undo-tree-history-save', please
;;; inspect the `*Messages*` buffer for clues such as the above examples.  Inasmuch
;;; as there is now a sanity check at the tail end of `undo-tree-history-save', any
;;; problems should materialize before a user actually tries to restore the history.
;;;
;;; The persistent undo storage has been expanded by adding certain features borrowed
;;; from the built-in `image-dired.el' library:
;;;
;;; `undo-tree-history-autosave':  When non-nil, `undo-tree-mode' will save undo
;;;                                history to a file when a buffer is saved; and,
;;;                                the save/restore functions attached to the
;;;                                following hooks will become active:
;;;                                -  `write-file-functions'
;;;                                -  `find-file-hook'
;;;                                To exclude certain files, users may wish to let-
;;;                                bind this variable to `nil` if it has a global
;;;                                non-nil value.  See also the next variable below.
;;;
;;; `undo-tree-history-file-exclusions':  A list of absolute file names that will be
;;;                                       excluded from the auto save/restore process.
;;;
;;; `undo-tree-history-alist':  Used when `undo-tree-history-storage' is 'classic.
;;;                             See the doc-string for customization tips/tricks.
;;;
;;; `undo-tree-history-directory':  Directory where history files are stored when
;;;                                `undo-tree-history-storage' is 'central.
;;;
;;; `undo-tree-history-storage':  How to store undo-tree history files.
;;;                               'classic:  See `undo-tree-history-alist'.
;;;                               'home (md5):  A folder in the HOME directory.
;;;                               'central (md5):  See `undo-tree-history-directory'.
;;;                               'local:  Create sub-directory in working directory.
;;;
;;; For those users who wish to use Emacs to view the saved/exported history, be
;;; aware that the undo history is one long string, and Emacs has trouble viewing a
;;; buffer with very long lines.  `(setq-default bidi-display-reordering nil)` will
;;; help permit Emacs to view buffers with very long lines without bogging down.
;;;
;;; The primary interactive functions for undo/redo in the working buffer are:
;;;
;;;   M-x undo-tree-classic-undo
;;;   M-x undo-tree-classic-redo
;;;   M-x undo-tree-linear-undo
;;;   M-x undo-tree-linear-redo
;;;
;;; The primary interactive functions for undo/redo in the visualization buffer are:
;;;
;;;   M-x undo-tree-visualize-classic-undo
;;;   M-x undo-tree-visualize-classic-redo
;;;   M-x undo-tree-visualize-linear-undo
;;;   M-x undo-tree-visualize-linear-redo
;;;
;;; If the built-in undo amalgamation business is not to your liking, it can be
;;; disabled to permit undo boundaries after every command:
;;;
;;;   ;;; https://stackoverflow.com/a/41560712/2112489
;;;   (advice-add 'undo-auto--last-boundary-amalgamating-number :override #'ignore)
;;;
;;; https://debbugs.gnu.org/cgi/bugreport.cgi?bug=27214
;;; https://emacs.stackexchange.com/q/33248/2287
;;; GARBAGE COLLECTION:  @lawlist has encountered a few situations where garbage
;;; collection truncates the `undo-tree-canary' in the `buffer-undo-list', which
;;; causes `undo-tree-transfer-list' to replace the existing `undo-tree-list'
;;; with the new tree fragment obtained from the `buffer-undo-list'.  In this
;;; circumstance, the user loses the entire undo-tree saved history!  The internal
;;; function responsible is `truncate_undo_list' in `undo.c`.  @lawlist has added a
;;; programmatic warning when loss of the existing `undo-tree-list' is about to
;;; occur; however, that does not fix the problem.  The relevant section from
;;; `truncate_undo_list' in `undo.c` is as follows:
;;;          /* When we get to a boundary, decide whether to truncate
;;;      either before or after it.  The lower threshold, undo_limit,
;;;      tells us to truncate after it.  If its size pushes past
;;;      the higher threshold undo_strong_limit, we truncate before it.  */
;;;          if (NILP (elt))
;;;     {
;;;       if (size_so_far > undo_strong_limit)
;;;         break;
;;;       last_boundary = prev;
;;;       if (size_so_far > undo_limit)
;;;         break;
;;;     }
;;; @lawlist opines that setting the `undo-limit' to the same value as
;;; `undo-strong-limit' will cause `truncate_undo_list' to preserve the
;;; `undo-tree-canary' in the `buffer-undo-list' by truncating before the boundary.
;;; This workaround is not ideal because a more recent undo would be truncated in
;;; lieu of an older undo.  One idea would be to convince the Emacs team to modify
;;; `truncate_undo_list' to preserve certain user-defined elements; e.g., a symbol
;;; of `undo-tree-canary'.
;;;
;;; The built-in function named `primitive-undo' defined in `simple.el` was used
;;; in the original version of `undo-tree.el`.  @lawlist created a modified
;;; function named `undo-tree--primitive-undo' that serves the same purpose, but
;;; permits setting a window-point in the working buffer while a user is in a
;;; different window such as the visualization buffer.  The revised version also
;;; merely reports a problem with a message instead of throwing an error when it
;;; encounters an `undo-tree-canary' in the wrong location.  This bug was noticed
;;; by @lawlist when performing undo/redo in region, and a Google search revealed
;;; that others too have experienced the same problem.  The bug is fairly easy to
;;; reproduce, but @lawlist has not yet invested the time to look for the cause
;;; and try to come up with a solution.  For anyone who wishes to work on fixing
;;; this and view other mentions of the same problem on the internet, Google:
;;;   "Unrecognized entry in undo list undo-tree-canary"
;;;
;;; The semi-linear visualization buffer view looks like this:
;;;
;;;        o-00001-a-0
;;;        20.34.55.46
;;;             |
;;;        o-br/pt-A-0
;;;        20.47.57.25
;;;        20.34.55.47
;;;         ____|_______________________________
;;;        /                                    \
;;;  o-00001-b-0                            o-00001-c-1
;;;  20.47.57.26                            20.34.55.48
;;;       |                                      |
;;;  o-00002-b-0                            o-00002-c-1
;;;  20.47.57.27                            20.34.55.49
;;;       |                                      |
;;;  o-00003-b-0                            o-00003-c-1
;;;  20.47.57.28                            20.34.55.50
;;;                                              |
;;;                                         o-00004-c-1
;;;                                         20.34.55.51
;;;                                              |
;;;                                         o-br/pt-B-1
;;;                                         21.25.32.05
;;;                                         20.35.06.89
;;;                                         20.35.02.23
;;;                                         20.34.58.43
;;;                                         20.34.55.57
;;;         _____________________________________|________________________
;;;        /            /                        |                        \
;;;  o-00001-d-0  o-00001-e-1               o-br/pt-C-2               o-00001-f-3
;;;  21.25.32.06  20.35.06.90               23.03.45.34               20.34.58.44
;;;                    |                    00.27.40.07                    |
;;;               o-00002-e-1               20.35.02.24               o-00002-f-3
;;;               20.35.06.91         ___________|___________         20.34.58.45
;;;                    |             /           |           \             |
;;;               o-00003-e-1  o-00001-g-0  o-00001-h-1  o-00001-i-2  o-00003-f-3
;;;               20.35.06.92  23.03.45.35  00.27.40.08  20.35.02.25  20.34.58.46
;;;                    |            |            |            |            |
;;;               o-00004-e-1  x-00002-g-0  o-00002-h-1  o-00002-i-2  o-00004-f-3
;;;               20.35.06.93  23:03:45:36  00.27.44.51  20.35.02.26  20.34.58.47
;;;                    |                                      |            |
;;;               o-00005-e-1                            o-00003-i-2  o-00005-f-3
;;;               20.35.06.94                            20.35.02.27  20.34.58.48
;;;                    |                                      |            |
;;;               o-00006-e-1                            o-00004-i-2  o-00006-f-3
;;;               20.35.06.95                            20.35.02.28  20.34.58.49
;;;                    |                                      |            |
;;;               o-00007-e-1                            o-00005-i-2  o-00007-f-3
;;;               20.35.06.96                            20.35.02.29  20.34.58.50
;;;                    |                                      |            |
;;;               o-00008-e-1                            o-00006-i-2  o-00008-f-3
;;;               20.35.06.97                            20.35.02.30  20.34.58.51
;;;
;;; To check for updates, please visit the source-code of the link listed at the
;;; top and also review the "Change Log" at the bottom.
;;;
;;; Bug reports and feature requests may be submitted via email to the address at
;;; the top.  Essentially, if it breaks in half, I can guarantee that you will
;;; have 2 pieces that may not necessarily be the same size.  :)  That being said,
;;; I will certainly make efforts to fix any problem that may arise relating to
;;; the semi-linear undo/redo feature.  A step 1-2-3 recipe starting from emacs -q
;;; would be very helpful so that @lawlist can observe the same behavior described
;;; in the bug report.  Here is an example to get you started:
;;;
;;; 1.  In an internet browser, visit: https://www.lawlist.com/lisp/undo-tree.el
;;;
;;;     Select/highlight all and copy everything to the clipboard.
;;;
;;; 2.  Launch Emacs without any user settings whatsoever:  emacs -q
;;;
;;;     If possible, please use the latest stable public release of Emacs.
;;;     @lawlist is using the GUI version of Emacs 25.2.1 on OSX.
;;;
;;; 3.  Switch to the `*scratch*` buffer.
;;;
;;; 4.  Paste the entire contents of the clpipboard into the `*scratch*` buffer.
;;;
;;; 5.  M-x eval-buffer RET
;;;
;;; 6.  M-x eval-expression RET (setq undo-tree-history-autosave t) RET
;;;
;;; 7.  M-x undo-tree-mode RET
;;;
;;;     The mode-line indicates `UT`, meaning that `undo-tree-mode' is active.
;;;
;;; 8.  M-x save-buffer RET
;;;
;;;     @lawlist chose to save the file to his desktop with the name `foo`, and
;;;     also chose to overwrite the file if it already existed; i.e., `y`.
;;;
;;;     Look at the lower left-hand side of the mode-line and notice that it
;;;     indicates an unmodified state; i.e., U:--- foo ....
;;;
;;; 9.  M-x undo-tree-classic-undo RET
;;;
;;;     Look at the lower left-hand side of the mode-line and notice that it
;;;     indicates we have returned to a modified state; i.e., U:**- foo ....
;;;
;;; 10. M-x undo-tree-classic-undo RET
;;;
;;;     The `undo-tree' library that we had previously pasted to the `*scratch*`
;;;     buffer should now be completely undone; i.e., removed.
;;;
;;; 11. M-x undo-tree-classic-undo RET
;;;
;;;     The buffer should be completely empty at this point; i.e., the initial
;;;     `*scratch*` message has been removed.
;;;
;;; 12. M-x undo-tree-classic-undo RET
;;;
;;;     The following `user-error' appears:
;;;
;;;       "user-error:  undo-tree--undo-or-redo:  No further undo information."
;;;
;;;     This is exactly the behavior that @lawlist expected would happen, so
;;;     everything up to this point appears to be working correctly.