I have a problem when using Etags in Emacs. Everytime I tap \M+. to jump to a difinition point, a query is always popping up, like:
Find tag (default function_name):
And I have to tap 'Enter' to make sure of it.
But in most cases, I find I can choose the default one. So is there any method with which I can surpress this message?
I found the reason is because:
(defun find-tag (tagname &optional next-p regexp-p)
(interactive (find-tag-interactive "Find tag: "))
...
)
Why do I have to choose a tag? Why can not the default one just be the word under the point? Can I just remove this line? (interactive), or is there a good solution?
Going shortly through a couple of defuns in the etags sources via Emacs's awesome C-h f, one can find that the default tag to search is determined via a function named find-tag-default.
This means you could just define the following function:
(defun find-tag-under-point ()
(interactive)
(find-tag (find-tag-default)))
Then you can bind this to whatever key you want via define-key or global-set-key or local-set-key.
(The interactive form is always necessary if you want a function to be a "command" which can be called with M-x or bound to a key.)
You can write your own functionality over the find-tag (or any interactive function likewise)
(defun find-tag-under-point (&optional arg)
(interactive "P")
(cond ((eq arg 9)
(let ((current-prefix-arg nil))
(call-interactively 'find-tag)))
(arg
(call-interactively 'find-tag))
(t
(find-tag (find-tag-default)))))
(global-set-key (kbd "M-.") 'find-tag-under-point)
Then hotkey C-9M-. calls find-tag (old function) as usual, but the behaviour of find-tag-under-point (new-function) by default is what you want.
Related
I'm trying to write a custom tab completion implementation which tries a bunch of different completions depending on where the point is. However, if none of the conditions for completions are met I would like tab to do what ever the current mode originally intended it to do.
Something like this:
(defun my-custom-tab-completion ()
(interactive)
(cond
(some-condition
(do-something))
(some-other-condition
(do-something-else))
(t
(do-whatever-tab-is-supposed-to-do-in-the-current-mode))) ;; How do I do this?
Currently I'm checking for specific modes and doing the right thing for that mode, but I really would like a solution that just does the right thing without me having to explicitly add a condition for that specific mode.
Any ideas of how to do this?
Thanks! /Erik
BTW, here is another solution:
(define-key <map> <key>
`(menu-item "" <my-cmd> :filter ,(lambda (cmd) (if <my-predicate> cmd))))
Here is a macro I wrote based on Emacs key binding fallback to define a keybinding conditionally. It adds the keybinding to the specified minor mode but if the condition is not true, the previously assigned action is executed:
(defmacro define-key-with-fallback (keymap key def condition &optional mode)
"Define key with fallback. Binds KEY to definition DEF in keymap KEYMAP,
the binding is active when the CONDITION is true. Otherwise turns MODE off
and re-enables previous definition for KEY. If MODE is nil, tries to recover
it by stripping off \"-map\" from KEYMAP name."
`(define-key ,keymap ,key
(lambda () (interactive)
(if ,condition ,def
(let* ((,(if mode mode
(let* ((keymap-str (symbol-name keymap))
(mode-name-end (- (string-width keymap-str) 4)))
(if (string= "-map" (substring keymap-str mode-name-end))
(intern (substring keymap-str 0 mode-name-end))
(error "Could not deduce mode name from keymap name (\"-map\" missing?)"))))
nil)
(original-func (key-binding ,key)))
(call-interactively original-func))))))
Then I can do things like the following to use the special binding for TAB only when I am on a header in outline-minor-mode. Otherwise my default action (I have both indent and yasnippets) is executed:
(define-key-with-fallback outline-minor-mode-map (kbd "TAB")
(outline-cycle 1) (outline-on-heading-p))
You could use functions such as key-binding (or its more specific variants global-key-binding, minor-mode-key-binding and local-key-binding) to probe active keymaps for bindings.
For example:
(call-interactively (key-binding (kbd "TAB")))
;; in an emacs-lisp-mode buffer:
;; --> indent-for-tab-command
;;
;; in a c++-mode buffer with yas/minor-mode:
;; --> yas/expand
One way to avoid infinite loops if your command is bound to TAB could be to put your binding in a minor mode, and temporarily disable its keymap while looking for the TAB binding:
(define-minor-mode my-complete-mode
"Smart completion"
:keymap (let ((map (make-sparse-keymap)))
(define-key map (kbd "TAB") 'my-complete)
map))
(defun my-complete ()
(interactive)
(if (my-condition)
(message "my-complete")
(let ((my-complete-mode nil))
(call-interactively (key-binding (kbd "TAB"))))))
It's possible that you could achieve this without any special workarounds at all. In most modes TAB just does indentation by default, but if you set the global variable tab-always-indent to 'complete it will try to do completion first, and indent if no completion is possible. This usually works really well, although if TAB is bound to another command in one of your major modes you might be out of luck.
If that works in the modes you need, you'll just need to add your custom completion function to the front of the list completion-at-point-functions in all applicable buffers (maybe using a mode hook). The completion-at-point command calls each function listed in completion-at-point-functions until one of them returns non-nil, so all you need to do to have your custom completion function "fall through" to the existing behavior is return nil from it.
This isn't a 100% answer to the question, but if the major modes you're working with are written according to the normal guidelines it might be the cleanest way.
define-key can accept quoted string or interactive lambdas like in this example.
;Static
(define-key evil-normal-state-mapr "m" 'evil-motion-state)
;Conditional
(define-key evil-normal-state-map "m"
(lambda () (interactive) (message "%s" major-mode)))
Lambda's can be replaced with named functions like my-tab-completion and used more effectively.
From define-key's docstring (Emacs 25)
DEF is anything that can be a key's definition:
nil (means key is undefined in this keymap),
a command (a Lisp function suitable for interactive calling),
a string (treated as a keyboard macro),
a keymap (to define a prefix key),
a symbol (when the key is looked up, the symbol will stand for its
function definition, which should at that time be one of the above,
or another symbol whose function definition is used, etc.),
a cons (STRING . DEFN), meaning that DEFN is the definition
(DEFN should be a valid definition in its own right),
or a cons (MAP . CHAR), meaning use definition of CHAR in keymap MAP,
or an extended menu item definition.
(See info node `(elisp)Extended Menu Items'.)
I would like to customize the behavior when I split windows in Emacs:
I am always splitting because I want to view a separate buffer side-by-side with the one I'm currently editing.
I use electric-buffer-list (bound to C-x C-b) to navigate buffers.
I end up doing all of the following separately:
C-x 3 to split horizontally.
C-x o to switch to the other window.
C-x C-b to invoke electric-buffer-list so I can select the buffer I want to view.
It seems like I should be able to write an Elisp function that will do all of this when I press C-x 3.
I found this post which describes the focus switching part of the behavior that I want, but I don't understand how to extend that answer to achieve all of what I'm trying to do.
Edit: After reviewing #lawlist's post and debugging my syntax, I think I want to do something like this:
(defun split-right-and-buffer-list ()
(interactive)
(split-window-horizontally)
(other-window 0)
(electric-buffer-list 0))
(global-set-key (kbd "C-x 3") 'split-right-and-buffer-list)
This does everything I want, except that the buffer list that comes up only lists the current buffer, instead of the normal list of all buffers that I get when I invoke electric-buffer-list from its key binding.
With some very small modifications the function you came up with will do what you want:
(defun split-right-and-buffer-list ()
(interactive)
(split-window-horizontally)
(other-window 1)
(electric-buffer-list nil))
(global-set-key (kbd "C-x 3") 'split-right-and-buffer-list)
Passing 1 instead of 0 as an argument to other-window causes Emacs to select the new window created as a result of calling split-window-horizontally.
Passing nil instead of 0 as an argument to electric-buffer-list causes Emacs to show all buffers, not just file-visiting ones.
The thing that can trip you up here is that this isn't mentioned in the documentation for electric-buffer-list (which doesn't include any information about the ARG it takes). But when you look at the source code of this command, you'll notice that it simply passes the value of the argument on to a function called list-buffers-noselect (and doesn't use it for anything else). The documentation of this function contains the missing piece of information mentioned above.
If you do not mind having custom commands to do what you want try the following functions
(require 'ido)
(defun my-split-window-open-buffer-right (buffer)
(interactive (list (ido-read-buffer "Please select a buffer: ")))
(select-window (split-window-right))
(switch-to-buffer buffer))
(defun my-split-window-open-buffer-below (buffer)
(interactive (list (ido-read-buffer "Please select a buffer: ")))
(select-window (split-window-below))
(switch-to-buffer buffer))
Bind them to keys of you liking. I would prefer this over redefining/advising functions I have not written.
I'm trying to write a custom tab completion implementation which tries a bunch of different completions depending on where the point is. However, if none of the conditions for completions are met I would like tab to do what ever the current mode originally intended it to do.
Something like this:
(defun my-custom-tab-completion ()
(interactive)
(cond
(some-condition
(do-something))
(some-other-condition
(do-something-else))
(t
(do-whatever-tab-is-supposed-to-do-in-the-current-mode))) ;; How do I do this?
Currently I'm checking for specific modes and doing the right thing for that mode, but I really would like a solution that just does the right thing without me having to explicitly add a condition for that specific mode.
Any ideas of how to do this?
Thanks! /Erik
BTW, here is another solution:
(define-key <map> <key>
`(menu-item "" <my-cmd> :filter ,(lambda (cmd) (if <my-predicate> cmd))))
Here is a macro I wrote based on Emacs key binding fallback to define a keybinding conditionally. It adds the keybinding to the specified minor mode but if the condition is not true, the previously assigned action is executed:
(defmacro define-key-with-fallback (keymap key def condition &optional mode)
"Define key with fallback. Binds KEY to definition DEF in keymap KEYMAP,
the binding is active when the CONDITION is true. Otherwise turns MODE off
and re-enables previous definition for KEY. If MODE is nil, tries to recover
it by stripping off \"-map\" from KEYMAP name."
`(define-key ,keymap ,key
(lambda () (interactive)
(if ,condition ,def
(let* ((,(if mode mode
(let* ((keymap-str (symbol-name keymap))
(mode-name-end (- (string-width keymap-str) 4)))
(if (string= "-map" (substring keymap-str mode-name-end))
(intern (substring keymap-str 0 mode-name-end))
(error "Could not deduce mode name from keymap name (\"-map\" missing?)"))))
nil)
(original-func (key-binding ,key)))
(call-interactively original-func))))))
Then I can do things like the following to use the special binding for TAB only when I am on a header in outline-minor-mode. Otherwise my default action (I have both indent and yasnippets) is executed:
(define-key-with-fallback outline-minor-mode-map (kbd "TAB")
(outline-cycle 1) (outline-on-heading-p))
You could use functions such as key-binding (or its more specific variants global-key-binding, minor-mode-key-binding and local-key-binding) to probe active keymaps for bindings.
For example:
(call-interactively (key-binding (kbd "TAB")))
;; in an emacs-lisp-mode buffer:
;; --> indent-for-tab-command
;;
;; in a c++-mode buffer with yas/minor-mode:
;; --> yas/expand
One way to avoid infinite loops if your command is bound to TAB could be to put your binding in a minor mode, and temporarily disable its keymap while looking for the TAB binding:
(define-minor-mode my-complete-mode
"Smart completion"
:keymap (let ((map (make-sparse-keymap)))
(define-key map (kbd "TAB") 'my-complete)
map))
(defun my-complete ()
(interactive)
(if (my-condition)
(message "my-complete")
(let ((my-complete-mode nil))
(call-interactively (key-binding (kbd "TAB"))))))
It's possible that you could achieve this without any special workarounds at all. In most modes TAB just does indentation by default, but if you set the global variable tab-always-indent to 'complete it will try to do completion first, and indent if no completion is possible. This usually works really well, although if TAB is bound to another command in one of your major modes you might be out of luck.
If that works in the modes you need, you'll just need to add your custom completion function to the front of the list completion-at-point-functions in all applicable buffers (maybe using a mode hook). The completion-at-point command calls each function listed in completion-at-point-functions until one of them returns non-nil, so all you need to do to have your custom completion function "fall through" to the existing behavior is return nil from it.
This isn't a 100% answer to the question, but if the major modes you're working with are written according to the normal guidelines it might be the cleanest way.
define-key can accept quoted string or interactive lambdas like in this example.
;Static
(define-key evil-normal-state-mapr "m" 'evil-motion-state)
;Conditional
(define-key evil-normal-state-map "m"
(lambda () (interactive) (message "%s" major-mode)))
Lambda's can be replaced with named functions like my-tab-completion and used more effectively.
From define-key's docstring (Emacs 25)
DEF is anything that can be a key's definition:
nil (means key is undefined in this keymap),
a command (a Lisp function suitable for interactive calling),
a string (treated as a keyboard macro),
a keymap (to define a prefix key),
a symbol (when the key is looked up, the symbol will stand for its
function definition, which should at that time be one of the above,
or another symbol whose function definition is used, etc.),
a cons (STRING . DEFN), meaning that DEFN is the definition
(DEFN should be a valid definition in its own right),
or a cons (MAP . CHAR), meaning use definition of CHAR in keymap MAP,
or an extended menu item definition.
(See info node `(elisp)Extended Menu Items'.)
I've looked through a number of other questions and el files looking for something i could modify to suit my needs but I'm having trouble so I came to the experts.
Is there anyway to have a key behave differently depending on where in the line the cursor is?
To be more specific I'd like to map the tab key to go to the end of the line if I'm in the middle of the line but work as a tab normally would if my cursor is positioned at the beginning of the line.
So far I have braces and quotes auto-pairing and re-positioning the cursor within them for C++/Java etc. I'd like to use the tab key to end-of-line if for example a function doesn't have any arguments.
Behaving differently depending on where point is in the line is the easy bit (see (if (looking-back "^") ...) in the code). "[Working] as a tab normally would" is the harder bit, as that's contextual.
Here's one approach, but I was thinking afterwards that a more robust method would be to define a minor mode with its own binding for TAB and let that function look up the fallback binding dynamically. I wasn't sure how to do that last bit, but there's a solution right here:
Emacs key binding fallback
(defvar my-major-mode-tab-function-alist nil)
(defmacro make-my-tab-function ()
"Return a major mode-specific function suitable for binding to TAB.
Performs the original TAB behaviour when point is at the beginning of
a line, and moves point to the end of the line otherwise."
;; If we have already defined a custom function for this mode,
;; return that (otherwise that would be our fall-back function).
(or (cdr (assq major-mode my-major-mode-tab-function-alist))
;; Otherwise find the current binding for this mode, and
;; specify it as the fall-back for our custom function.
(let ((original-tab-function (key-binding (kbd "TAB") t)))
`(let ((new-tab-function
(lambda ()
(interactive)
(if (looking-back "^") ;; point is at bol
(,original-tab-function)
(move-end-of-line nil)))))
(add-to-list 'my-major-mode-tab-function-alist
(cons ',major-mode new-tab-function))
new-tab-function))))
(add-hook
'java-mode-hook
(lambda () (local-set-key (kbd "TAB") (make-my-tab-function)))
t) ;; Append, so that we run after the other hooks.
This page of Emacs Wiki lists several packages (smarttab, etc.) which make TAB do different things depending on the context. You can probably modify one of them to do what you want.
I want to make one keystroke, say C-F12, to do delete-other-windows or winner-undo. I think it's easy if I already learning Emacs Lisp programming, and set a boolean flag. That is, if previously it run delete-other-window, now it'll run winner-undo.
How do you do that in Emacs Lisp?
Thanks
Try something like this
(setq c-f12-winner-undo t)
(define-key (current-global-map) [C-f12]
(lambda()
(interactive)
(if c-f12-winner-undo
(winner-undo)
(delete-other-windows))
(setq c-f12-winner-undo (not c-f12-winner-undo))))
(defun swdev-toggle-sole-window ()
(interactive)
(if (cdr (window-list))
(delete-other-windows)
(winner-undo)))
(global-set-key (kbd "<C-f12>") 'swdev-toggle-sole-window)
The first line starts the declaration of a function called swdev-toggle-sole-window, taking no argument.
This function is declared as interactive, i.e. it can be called with M-x or through a key binding.
If the window list contains more than one element, i.e. if there is more than one window, …
… then delete other windows …
… else undo the window deletion.
Bind the function to the key C-f12.
Here's a solution using the approach taken by Emacs' recenter-top-bottom function:
(defun delete-other-window-or-winner-undo ()
"call delete-other-window on first invocation and winner-undo on subsequent invocations"
(interactive)
(if (eq this-command last-command)
(winner-undo)
(delete-other-windows)))
(global-set-key (kbd "<C-f12>") 'delete-other-window-or-winner-undo)