Intro: The function org-preview-latex-fragment either renders the latex in entire section OR only one latex fragment (if the point is in it). However, the clear (C-c C-c) always removes all the images.
Q: is there a way to remove only one image (the one pointed to)?
C-c C-x C-l runs org-toggle-latex-fragment and will toggle on/off the fragment that you are on at the time or with a prefix argument, all fragmens in the current subtree, or all fragments in the buffer. See the documentation of the function for more details.
Note that org-preview-latex-fragment is obsolete since org 8.3 and is just an alias to org-toggle-latex-fragment. Also note that C-c C-c does not do anything useful for fragments any longer: this is an attempt to reduce the overload that this particular key sequence currently carries.
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In Emacs I'm editing some source code, and I hit <tab>. Emacs indents the line to n spaces. I'd like to change the amount that indents for that kind of line. How do I figure out what rule emacs applied to indent that line by n spaces?
I want to change n, but I need to figure out which of the many indentation-related variables Emacs just used.
A generic answer is difficult. Some modes will make this more apparent than others, but in the general case (as they are free to implement indentation however they wish) I don't think you'll get away from needing to read some elisp.
Starting with the binding for TAB will work, but might be slightly time-consuming depending on how many layers of indirection are involved.
If you know that the major mode in question implements its own indentation, then one (non-rigorous, but fast) approach that you could try to help track down the functions being called is to use ELP, the built in elisp profiler. elp-instrument-package will instrument for profiling all functions with names matching the prefix string argument you specify. Therefore you might do something like the following in a PHP file (noting that php-mode tells you that it is derived from c-mode)
M-x elp-instrument-package RET php- RET
M-x elp-instrument-package RET c- RET
M-x elp-instrument-package RET indent RET
Now type TAB in your source code, and run M-x elp-results to see which of those instrumented functions were called.
At this point you're on your own -- look for the likely suspects, and see what the code is doing -- but it can be a handy way to filter the search.
Once you've finished, use M-x elp-restore-all to prevent any further profiling.
If you're using a mode based on cc-mode (e.g. c-mode, c++-mode, java-mode, etc.), you can hit C-c C-s and it'll tell you what syntactic category the line is. If you want to change it, hit C-c C-o and you'll be guided through the process. Check out the cc-mode docs on customization for more details: https://www.gnu.org/s/emacs/manual/html_node/ccmode/Customizing-Indentation.html
If you happen to enjoy getting your hands really dirty, there's always the elisp debugger to tell you just what Emacs is up to.
If you hit C-h k TAB you'll find the function that Emacs is running (e.g. indent-for-tab-command) then you can do M-x debug-on-entry RET indent-for-tab-command RET. Now whenever you hit TAB you'll pop up a debugger and can watch the execution step by step.
Depending on your taste for debugging, it's either a maddening or enlightening experience. Either way, don't forget to M-x cancel-debug-on-entry when you're done.
Imagine the dunnet.el game, the eliza doctor or the IELM mode...; This is, evaluating answers and prompting new questions on the main buffer, then making some actions according to their elisp rules.
I would to create something like an interactive assistant, BUT NOT prompting from minibuffer as (interactive) does (not doing M-x)... I need a kind of REPL loop. So the question i how to get interaction on the working buffer (the main screen), like any text conversational/adventure, but for call my defun'ed functions on this way.
So i need a basic elisp skeleton, to make a custom REPL. The target is to make an assistant with a natural language, then parsing the anwsers, and making some actions according the rules.
Thank you for your time,
Steve,
Check out ielm, which is an elisp repl included with emacs.
Depending on what can go on in your buffer, can you just give it a major mode with an appropriate re-binding of return? (This answer vaguely inspired by Lisp-Interaction-Mode's C-j)
You should bind all keys that use for moving in buffer like C-p C-n, Up Down Arrows/ page up/down just bind them to (lambda ()). change function for C-b and C-f (Left Right Arrows) if cursor position is in beginning or end of the line. And bind Return key to function that read current line from end to optional prompt (you can use Regex to remove the prompt) do whatever you want with that string, and then go to the next line in the buffer and print your result.
Vim completes words and lines with CTRL-X P and CTRL-L. There's a Emacs plugin called Company mode but this plugin interfere and cause conflicts with lots of things within Emacs (with global linum and yasnippets). I know that I can complete words with CTRL-/ in Emacs. But it is possible to take previously written lines to complete code?
Maybe you're looking for hippie-expand? From that web page (as of this writing, anyway):
HippieExpand looks at the word before
point and tries to expand it in
various ways including expanding from
a fixed list (like expand-abbrev),
expanding from matching text found in
a buffer (like dabbrev-expand) or
expanding in ways defined by your own
functions. Which of these it tries and
in what order is controlled by a
configurable list of functions.
For a comprehensive list of completion options visit the emacs wiki page on completion.
There are a gazillion ways to do completion in Emacs. Some are mode specific, some inline, some configurable and what not. Here is a list of modes that might help you.
Use numberic argument to complete by line, say M-5 M-/ will complete by line, while M-/ alone still complete the normal way.
hippe-expend function has a very useful feature which is :
With a positive numeric argument, jumps directly to the ARG next function in this list. With a negative argument or just C-u, undoes the expansion.
Customize the expansion functions in hippie-expand-try-functions-list and put the function try-expand-line as 5th list element, then you could use M-5 M-/ to complete by line.
This tip is very handy and useful and I highly recommend it.
Also worth noting: if your window manager does not steal Alt-tab, emacs will auto-complete with Alt-tab (I set up my window manager to user the "windows key" instead of alt for this very reason).
If you are using evil, this is the most vim-like solution I use:
(defun my-expand-lines ()
(interactive)
(let ((hippie-expand-try-functions-list
'(try-expand-line-all-buffers)))
(call-interactively 'hippie-expand)))
(define-key evil-insert-state-map (kbd "C-x C-l") 'my-expand-lines)
This way you can use our old friend C-x C-l in insert mode for whole line all buffers completion.
Thanks #ymln for the suggestion of using try-expand-line-all-buffers.
I'm trying to figure out how the "hyperlink" works in the *Help* buffer (so that I can implement something similar in the output of M-x compile). Here is a more detailed description of the behaviour I want to imitate:
M-x describe-function find-file opens up a *Help* buffer. The first line of this buffer (for me) shows: find-file is an interactive Lisp function in files.el. files.el is underlined and clicking (or hitting enter when point is there) opens a new buffer with files.el and the point positioned at the definition of find-file. Doing a describe-key for says invokes push-button in button.el, which tells me Perform the action specified by a button at location pos - but how do I define a button and associate an action with that button in my own buffer?
The major mode of the *Help* buffers is help-mode. In its source code (help-mode.el), you find function help-make-xrefs that "Parse[s] and hyperlink[s] documentation cross-references in the given BUFFER". You may check it how it was implemented.
Otherwise, I'd suggest using org-mode instead, which uses the simple form [[URI][caption]] to mark hyperlinks.
Notepad++ has a convenient feature: if you select a word in your text (not necessarily a keyword), the word is highlighted throughout the text. Can this be done in Emacs as well? And if so, how?
It doesn't necessarily have to work exactly like Notepad++ (i.e., via selection); ideally, I would like to set up a key binding that causes all occurrences of the word under cursor to be highlighted.
It would be great if the highlights were permanent, i.e., moving point away from a highlighted word should not cause the highlight to be removed.
Also, it would be useful if there was a solution that made it possible to navigate between highlights (using custom key bindings).
The hi-lock suggestions are good. I think it's easier to use the M-x versions, though:
M-x highlight-regexp RET <REGEXP>
M-x highlight-phrase RET <REGEXP>
highlight-phrase is just a bit of sugar around highlight-regexp that ignores case and translates a space in the regex to match arbitrary whitespace. Handy.
Maybe highlight-symbol.el at http://nschum.de/src/emacs/highlight-symbol/ is what you are looking for:
Type C-s, then type the current word or type C-w. As a bonus, you can now hit C-s again to search for the word.
This is called incremental search.
What I use is idle-highlight
http://www.emacswiki.org/emacs/IdleHighlight
M-x idle-highlight sets an idle timer that highlights all occurences in the buffer of the word under the point.
To enable it for all programming modes, in ~/.emacs.d/init.el:
;; highlight words
(add-hook 'prog-mode-hook (lambda () (idle-highlight-mode t)))
Light-symbol will highlight whatever symbol point is over.
Alternately, you can use occur, which lists all lines matching a regexp. It's useful to quickly see all functions in a class.
Nobody mentioned symbol-overlay mode. It's basically a better rewrite of highlight-symbol-mode. "Better" as in, lacks bugs of original highlight-symbol (such as, temporary highlight getting stuck, or the temporary highlight disappearing for moving inside the highlighted word; or not being able to highlight symbols like *), better integrated, and maintained. See "Advantages" paragraph of its README.
You can install it as usual, with M-xpackage-install (make sure to update package list beforehand with package-list-packages). For reference, at the bottom I attached code I use to enable the mode and disable a few of the more advanced features which you may or may not want.
Notepad++ has a convenient feature: if you select a word in your text (not necessarily a keyword), the word is highlighted throughout the text. Can this be done in Emacs as well? And if so, how?
Once you enable overlay-symbol, occurrences on the screen will be shown for every word that you put cursor upon after a timeout (timeout by default is 0.5s, can be configured with symbol-overlay-idle-time variable). If a word don't get highlighted, this means there's just one match on the screen (the one you put cursor upon), hence there's no need to highlight it.
It would be great if the highlights were permanent, i.e., moving point away from a highlighted word should not cause the highlight to be removed.
To highlight the word under cursor permanently there's a function symbol-overlay-put. To unhighlight call it once again.
In my config example it's bound to Logo+` key.
(require 'symbol-overlay)
(defun enable-symbol-overlay-mode ()
(unless (or (minibufferp)
(derived-mode-p 'magit-mode)
(derived-mode-p 'xref--xref-buffer-mode))
(symbol-overlay-mode t)))
(define-global-minor-mode global-symbol-overlay-mode ;; name of the new global mode
symbol-overlay-mode ;; name of the minor mode
enable-symbol-overlay-mode)
(global-symbol-overlay-mode) ;; enable it
(global-set-key (kbd "s-`") 'symbol-overlay-put)
(setq symbol-overlay-ignore-functions nil) ;; don't ignore keywords in various languages
(setq symbol-overlay-map (make-sparse-keymap)) ;; disable special cmds on overlays
This may not be as nice as what you were hoping but if you put
(global-hi-lock-mode 1)
in your .emacs file then you can type C-x w h REGEX <RET> <RET> to highlight all occurances of REGEX, and C-x w r REGEX <RET> to unhighlight them again. Again, not as elegant as you'd probably like, but it'll work.
Try http://www.emacswiki.org/emacs/msearch.el
All occurences of the text selected with the cursor are highlighted.
You have to drag over the string which you want to highlight. That enables you to easily change the selection without changing the highlight.
If you want to preserve the highlighting of a string you can freeze it.
You can enslave a buffer to another buffer. Text selected in the master buffer will also be highlighted in the slave buffer. That is useful for comparing buffers.
It is also useful for taking notes in one buffer while you investigate the text in another one. You can have a collection of keywords in the notes buffer. Drag over such a keyword and its occurences in the investigated text will be highlighted.
I am using this stuff for years now. I added the freezing quite recently. So, maybe something is broken. If this is the case leave me a note on http://www.emacswiki.org/emacs/msearch or here.
Check Interactive Highlighting
Should be:
C-x w h word <RET> <RET>
Try iedit. It highlights the word at point and lets you edit all occurrences of it easily. With an additional keystroke (C-'), it hides all the lines without that word in it. Very handy!
Commands in library highlight.el
let you (un)highlight text matching a regexp (in this case a symbol), using overlays or text properties. You can cycle among the occurrences. Highlighting can be temporary or persistent. (more info).
This maybe won't highlight but will search for a word without you needing to type it...
when you've reached the word you wanted to search, C-S, then read the full word with C-W then you can C-S and it will search for it. In my Emacs it also highlights all instances in the document.
This package available in Melpa works, you can customize the highlight style as well.
https://github.com/ignacy/idle-highlight-in-visible-buffers-mode