I am involved in python project where tabs are used, however i am not using them in every other code i write, it is vital to use them in that particular project. Projects are located in one directory under specific directories. I.E:
\main_folder
\project1
\project2
\project3
...etc
I have couple functions/hooks on file open and save that untabify and tabify whole buffer i work on.
;; My Functions
(defun untabify-buffer ()
"Untabify current buffer"
(interactive)
(untabify (point-min) (point-max)))
(defun tabify-buffer ()
"Tabify current buffer"
(interactive)
(tabify (point-min) (point-max)))
;; HOOKS
; untabify buffer on open
(add-hook 'find-file-hook 'untabify-buffer)
; tabify on save
(add-hook 'before-save-hook 'tabify-buffer)
If i put it in .emacs file it is run on every .py file i open which is not what i want. What i`d like to have is to have these hooks used only in one particular folder with respective subfolders. Tried .dir_locals but it works only for properties not hooks. I can not use hooks in specific modes (i.e. python-mode) as almost all projects are written in python. To be honest i tried writing elisp conditional save but failed.
A very easy solution is to just add a configuration variable that can be used to disable the hooks. For example:
(defvar tweak-tabs t)
(add-hook 'find-file-hook
(lambda () (when tweak-tabs (untabify (point-min) (point-max)))))
(add-hook 'before-save-hook
(lambda () (when tweak-tabs (tabify (point-min) (point-max)))))
Now you can add a .dir-locals.el file in the relevant directories, setting tweak-tabs to nil, disabling this feature there.
(But another problem is that this is a pretty bad way to deal with tabs. For example, after you save a file you do see the tabs in it.)
Just for the record, to answer the literal question in the title (as I reached this question via a web search): one way to add a hook that depends on file location is to make it a function that checks for buffer-file-name. (Idea from this answer.)
For example, for the exact same problem (turn on tabs only in a particular directory, and leave tabs turned off elsewhere), I'm currently doing something like (after having installed the package smart-tabs-mode with M-x package-install):
(smart-tabs-insinuate 'python) ; This screws up all Python files (inserts tabs)
(add-hook 'python-mode-hook ; So we need to un-screw most of them
(lambda ()
(unless (and (stringp buffer-file-name)
(string-match "specialproject" buffer-file-name))
(setq smart-tabs-mode nil)))
t) ; Add this hook to end of the list
(This is a bit inverted, as smart-tabs-insinuate itself modifies python-mode-hook and then we're modifying it back, but it should do as an example.)
Related
I indicate my muse-mode files (usually named with .txt suffix) as being muse-mode by starting them with a "#title". To do this, I have
;; muse-mode on *.txt files, if a #title or sect. header is on top 4 lines
(add-hook 'text-mode-hook
(lambda ()
(unless (or (eq major-mode 'muse-mode)
(not (stringp buffer-file-truename)))
(when (equal (file-name-extension buffer-file-truename) "txt")
(save-excursion
(goto-line 5)
(if (re-search-backward "\* [A-Z][a-z]+.*\\|#title " 1 t)
(muse-mode)))))))
If I also have
(add-to-list 'auto-mode-alist '("\\.txt$" . visual-line-mode))
in the .emacs (following the code above), then muse-mode no longer works. Though if I invoke visual-line-mode with Meta-x from within emacs on a muse file, it doesn't mess things up.
Ideally, I would like to have visual-line-mode working on all .txt files, but without messing up muse. Or else, I would like to start all .txt files in visual-line-mode except when they are muse files.
The variable 'auto-mode-alist chooses the major mode.
visual-line-mode is a minor mode, and by adding it to the 'auto-mode-alist you're making it act like a major mode, which replaces the text-mode you were starting with.
Instead, add turn-on-visual-line-mode-in-txt to the text-mode-hook like so:
(add-hook `text-mode-hook 'turn-on-visual-line-mode)
(defun turn-on-visual-line-mode-in-txt ()
(when (and (buffer-file-name)
(string-match ".txt$" (buffer-file-name)))
(turn-on-visual-line-mode)))
For more information on the differences, read the manual for major and minor modes.
I think #treyJackson identified the problem, but here are some extra comments:
BTW, your use of a text-mode-hook to switch to muse-mode will misbehave in various circumstances (because you first switch to text-mode, then halfway through you activate muse-mode, after which the end of the text-mode activation (usually, not much left to do, but there could be more functions on the text-mode-hook to run) will still be performed). A more robust approach might be to do:
(add-to-list 'auto-mode-alist '("\\.txt\\'" . text-or-muse-mode))
(defun text-or-muse-mode ()
(if (save-excursion
(goto-line 5)
(re-search-backward "\\* [A-Z][a-z]+.*\\|#title " 1 t))
(muse-mode)
(text-mode)))
Of course, you could also use a -*- muse -*- on the first line, or rely on magic-mode-alist instead.
Is there any way to have EMACS save your undo history between sessions?
I'm aware of the savehist lib, the saveplace lib, the desktop lib, and the windows lib, these all provide some session control but none seem to save the undo history.
From version 0.4 onwards, undo-tree supports persistent storage of undo-tree data between sessions "out of the box". (Note that there are significant bug-fixes related to this feature in more recent versions; the latest version at the time of writing is 0.6.3.)
Simply enable the undo-tree-auto-save-history customization option to automatically save and load undo history in undo-tree buffers. Or use the undo-tree-save/load-history commands to save and load undo history manually.
You need at least Emacs version 24.3 for this to work reliably, but with a recent enough Emacs it works very well.
Add the following to your .emacs file :
(global-undo-tree-mode)
(setq undo-tree-auto-save-history t)
(setq undo-tree-history-directory-alist '(("." . "~/.emacs.d/undo")))
Explanation
(global-undo-tree-mode) enables undo tree.
(setq undo-tree-auto-save-history t) enables auto save of undo history.
(setq undo-tree-history-directory-alist '(("." . "~/.emacs.d/undo"))) so that your project does not get littered with undo-history savefiles.
Here's some code I wrote which seems to do the trick. It isn't bullet-proof, as in, it doesn't handle all the file handling intricacies that Emacs does (e.g. overriding where auto-save files are put, symlink handling, etc.). But, it seemed to do the trick for some simple text files I manipulated.
(defun save-undo-filename (orig-name)
"given a filename return the file name in which to save the undo list"
(concat (file-name-directory orig-name)
"."
(file-name-nondirectory orig-name)
".undo"))
(defun save-undo-list ()
"Save the undo list to a file"
(save-excursion
(ignore-errors
(let ((undo-to-save `(setq buffer-undo-list ',buffer-undo-list))
(undo-file-name (save-undo-filename (buffer-file-name))))
(find-file undo-file-name)
(erase-buffer)
(let (print-level
print-length)
(print undo-to-save (current-buffer)))
(let ((write-file-hooks (remove 'save-undo-list write-file-hooks)))
(save-buffer))
(kill-buffer))))
nil)
(defvar handling-undo-saving nil)
(defun load-undo-list ()
"load the undo list if appropriate"
(ignore-errors
(when (and
(not handling-undo-saving)
(null buffer-undo-list)
(file-exists-p (save-undo-filename (buffer-file-name))))
(let* ((handling-undo-saving t)
(undo-buffer-to-eval (find-file-noselect (save-undo-filename (buffer-file-name)))))
(eval (read undo-buffer-to-eval))))))
(add-hook 'write-file-hooks 'save-undo-list)
(add-hook 'find-file-hook 'load-undo-list)
desktop-save-mode does not save buffer-undo-list by default. You just have to tell him!
(add-to-list 'desktop-locals-to-save 'buffer-undo-list)
Emacs Session appears to support this:
(add-to-list 'session-locals-include 'buffer-undo-list)
I have managed to get the undo history working by using the information provided here: http://emacs.stackexchange.com/q/3725/2287
Instead of patching the original file desktop.el.gz I created an advice that temporarily overrides (buffer-local-variables) then I use it together with the function that gathers information about the buffer.
(defun +append-buffer-undo-list-to-buffer-local-variables-advice (orig-fn &rest args)
"Override `buffer-local-variables' and call ORIG-FN with ARGS.
There is a bug in Emacs where the `buffer-undo-list' data is
missing from the output of `buffer-local-variables'. This
advice temporarily overrides the function and appends the
missing data."
(let ((orig-buffer-local-variables-fn (symbol-function 'buffer-local-variables)))
(cl-letf (((symbol-function 'buffer-local-variables)
#'(lambda () (append (funcall orig-buffer-local-variables-fn)
`(,(cons 'buffer-undo-list buffer-undo-list))))))
(apply orig-fn args))))
(advice-add #'desktop-buffer-info :around #'+append-buffer-undo-list-to-buffer-local-variables-advice)
(push 'buffer-undo-list desktop-locals-to-save)
(desktop-save-mode 1)
I hope this helps someone else.
Everytime I save a file in emacs lisp mode, I want it to be automatically byte-compiled. Can someone come up with a function that does byte-compile-file on the current file if the current major mode is emacs lisp mode? I want to add-hook that function to after-save-hook.
I found an answer here. The following does it all. It is a copy from the linked site.
(add-hook 'after-save-hook
(lambda ()
(if (eq major-mode 'emacs-lisp-mode)
(save-excursion (byte-compile-file buffer-file-name)))))
Is there any way to have EMACS save your undo history between sessions?
I'm aware of the savehist lib, the saveplace lib, the desktop lib, and the windows lib, these all provide some session control but none seem to save the undo history.
From version 0.4 onwards, undo-tree supports persistent storage of undo-tree data between sessions "out of the box". (Note that there are significant bug-fixes related to this feature in more recent versions; the latest version at the time of writing is 0.6.3.)
Simply enable the undo-tree-auto-save-history customization option to automatically save and load undo history in undo-tree buffers. Or use the undo-tree-save/load-history commands to save and load undo history manually.
You need at least Emacs version 24.3 for this to work reliably, but with a recent enough Emacs it works very well.
Add the following to your .emacs file :
(global-undo-tree-mode)
(setq undo-tree-auto-save-history t)
(setq undo-tree-history-directory-alist '(("." . "~/.emacs.d/undo")))
Explanation
(global-undo-tree-mode) enables undo tree.
(setq undo-tree-auto-save-history t) enables auto save of undo history.
(setq undo-tree-history-directory-alist '(("." . "~/.emacs.d/undo"))) so that your project does not get littered with undo-history savefiles.
Here's some code I wrote which seems to do the trick. It isn't bullet-proof, as in, it doesn't handle all the file handling intricacies that Emacs does (e.g. overriding where auto-save files are put, symlink handling, etc.). But, it seemed to do the trick for some simple text files I manipulated.
(defun save-undo-filename (orig-name)
"given a filename return the file name in which to save the undo list"
(concat (file-name-directory orig-name)
"."
(file-name-nondirectory orig-name)
".undo"))
(defun save-undo-list ()
"Save the undo list to a file"
(save-excursion
(ignore-errors
(let ((undo-to-save `(setq buffer-undo-list ',buffer-undo-list))
(undo-file-name (save-undo-filename (buffer-file-name))))
(find-file undo-file-name)
(erase-buffer)
(let (print-level
print-length)
(print undo-to-save (current-buffer)))
(let ((write-file-hooks (remove 'save-undo-list write-file-hooks)))
(save-buffer))
(kill-buffer))))
nil)
(defvar handling-undo-saving nil)
(defun load-undo-list ()
"load the undo list if appropriate"
(ignore-errors
(when (and
(not handling-undo-saving)
(null buffer-undo-list)
(file-exists-p (save-undo-filename (buffer-file-name))))
(let* ((handling-undo-saving t)
(undo-buffer-to-eval (find-file-noselect (save-undo-filename (buffer-file-name)))))
(eval (read undo-buffer-to-eval))))))
(add-hook 'write-file-hooks 'save-undo-list)
(add-hook 'find-file-hook 'load-undo-list)
desktop-save-mode does not save buffer-undo-list by default. You just have to tell him!
(add-to-list 'desktop-locals-to-save 'buffer-undo-list)
Emacs Session appears to support this:
(add-to-list 'session-locals-include 'buffer-undo-list)
I have managed to get the undo history working by using the information provided here: http://emacs.stackexchange.com/q/3725/2287
Instead of patching the original file desktop.el.gz I created an advice that temporarily overrides (buffer-local-variables) then I use it together with the function that gathers information about the buffer.
(defun +append-buffer-undo-list-to-buffer-local-variables-advice (orig-fn &rest args)
"Override `buffer-local-variables' and call ORIG-FN with ARGS.
There is a bug in Emacs where the `buffer-undo-list' data is
missing from the output of `buffer-local-variables'. This
advice temporarily overrides the function and appends the
missing data."
(let ((orig-buffer-local-variables-fn (symbol-function 'buffer-local-variables)))
(cl-letf (((symbol-function 'buffer-local-variables)
#'(lambda () (append (funcall orig-buffer-local-variables-fn)
`(,(cons 'buffer-undo-list buffer-undo-list))))))
(apply orig-fn args))))
(advice-add #'desktop-buffer-info :around #'+append-buffer-undo-list-to-buffer-local-variables-advice)
(push 'buffer-undo-list desktop-locals-to-save)
(desktop-save-mode 1)
I hope this helps someone else.
I know about M-x dire, but would like to customize it. I would like to hit one key (for example F2) and get dire buffer open. When I navigate across the directory hierarchy it shouldn't open new buffers.
And when I finally open the file it also shouldn't open new buffer for it (not strictly necessary, but strongly preferred).
Of course this behavior can be global, i.e. for all dire buffers/invocations.
Check out dired-single, which pretty much does what you want (except that last bit, where it reuses the dired buffer for the newly visted file).
Caveat Lector: I wrote it, so I'm biased towards its usefulness.
Some alternatives - EmacsWiki: DiredReuseDirectoryBuffer, and this short snippet from an awkwardly-formatted blog-entry.
caveat: haven't tried them, myself.
I know this is very old but All you have to do is press 'a' on a dir or file to get this functionality. It's already there.
Here's what I finally used:
(require 'dired)
(global-set-key [(f2)] 'my-dired)
(defun my-dired ()
(interactive)
(dired (file-name-directory (buffer-file-name))))
(defadvice dired-advertised-find-file (around dired-subst-directory activate)
"Replace current buffer if file is a directory."
(interactive)
(let ((orig (current-buffer)) (filename (dired-get-filename :no-error-if-not-filep t)))
ad-do-it
(when (not (eq (current-buffer) orig)) (kill-buffer orig))))