I'm curious as to whether or not there's a simple way to edit the face of a block of text using a function.
Specifically, I'm working on a calendar major mode that I created, and I want to define a function that will be bound to a keystroke within this major mode. I want to be able to mark a group of text, and then change its face using this keybinding to mark it as "done", etc.
I did some research and wasn't able to find this exact issue. Also, I know I can basically do this exact thing in org-mode, but I really want to create my own mode to enable more flexibility on my end.
If you are using the 3-month mini-calendar as a basis to create your major-mode, then there is already a facility to do this. To see how this looks like, type M-x calendar and then M-x calendar-mark-holidays. To see how this works, you can type M-x find-function RET calendar-mark-holidays RET and see that it uses the function calendar-mark-visible-date -- so there you have it, that is your function of interest. Drew Adams has a fancier calendar mark date that has some additional options: https://www.emacswiki.org/emacs/calendar%2B.el . These markings are overlays and can be controlled with priorities to have one supersede another so that it is not actually necessary to remove a color unless you want to.
Here is a quick example of a keyboard shortcut/function that uses the F5 key: (define-key calendar-mode-map [f5] (lambda () (interactive) (calendar-mark-visible-date (calendar-cursor-to-date 'signal-error) '(:background "yellow" :foreground "black"))))
Sounds like ad hoc, not syntax, highlighting: You want to manually choose specific arbitrary text to highlight, and you want to choose the highlighting face to use for this or that chosen bit of text.
You can use library Highlight (highlight.el) to do that.
Command hlt-choose-default-face chooses the face to use for subsequent highlighting (it reads a face name or a color name, with completion).
Another way to choose the highlighting face is to use command
hlt-next-face or hlt-previous-face. These cycle among a
smaller set of faces and background colors, the elements in the
list value of option hlt-auto-face-backgrounds. You can use a
numeric prefix argument with these commands to choose any of the
elements by its absolute position in the list.
There are commands (e.g., hlt-highlight) to highlight or unhighlight the active region, or you can drag the mouse to highlight (or unhighlight). By default they use the last default face you chose.
For persistent highlighting, see Temporary or Permanent Highlighting.
Related
In EMACS the default seems to be to 'copy' any text highlighted with the mouse. I'm attempting to replicate the functionality of modern text editors, where I can highlight a section of text and press 'paste' to replace it. I have so far added
(delete-selection-mode 1)
to my init.el
The problem is, if I copy something, then highlight to paste in its place, I end up pasting what I had just highlighted, changing nothing.
What do I need to change to fix that behaviour?
The most powerful element of emacs is its introspection features, lets have a look at how we can use them to try and solve this problem. We must use the power of the source.
One of the most important tools for introspection in emacs is the describe-key command which is bound to C-h k. It brings up the documentation of whatever keystroke is called after it. So in our case if we press C-h k and then click and drag we will see the documentation for <down-mouse-1> and more importantly for <drag-mouse-1>. The documentation states that "<drag-mouse-1> at that spot runs the command mouse-set-region". Below it then gives some documentation for this command. It says
Set the region to the text dragged over, and copy to kill ring.
This should be bound to a mouse drag event.
See the ‘mouse-drag-copy-region’ variable to control whether this
command alters the kill ring or not.
Now we know that somehow mouse-drag-copy-region controls whether or not the highlighted text is copied.
If we follow the link of that variable it tells us the default value and some documentation:
If non-nil, copy to kill-ring upon mouse adjustments of the region.
Now all we have to do is set the variable to be nil to get the effect that you want. Place the following code at the end of your init file and you should be all set
(setq mouse-drag-copy-region nil)
I hope that this helps you with this problem and that more importantly it helps you with further issues.
By default, selecting a region with the mouse does not copy the text to the kill ring. If your Emacs does this, you probably have set the variable mouse-drag-copy-region.
In a fresh Emacs (24.5 started using -Q), you can do the following:
Start delete-selection-mode.
Mark a region using the mouse. Copy it using M-w.
Mark a second region. Replace it with the first using C-y.
I see two alternatives, neither of which does exactly what you request. (For both, yes, turn on delete-selection-mode.)
Use the secondary selection for the text to copy, and use the primary selection (the region) for the text to be replaced.
You copy text into the secondary selection using the Meta key plus the mouse - for example, press and hold Meta (the Alt key, usually) while dragging or double-clicking mouse-1.
You paste the secondary selection using Meta plus mouse-2.
Select text with the mouse, then copy it to the kill-ring using M-w. Then select the text to replace with the mouse and use C-y to paste the copied text to replace it.
After searching for a word using an I-search, the selection mode remains enabled and pressing the escape button just once does not turn it off.
Is it possible to search for a word (forwards / backwards) and quickly go on about my business without pressing a bunch of keys to exit out of the select mode?
Also, the selection mode looks useful -- is there any way to turn it on / off without first performing a search?
Thanks.
You probably have transient-mark-mode enabled, which is now the default Emacs behavior. (It was not enabled by default in older versions of Emacs). If you're not familiar with it you may want to read about it in the Emacs manual.
You can set the mark (begin selection) using Control-space (C-SPC, the default key binding for set-mark-command). Then you can use other navigation keys to extend the selected region before you operate on it. For example: C-SPC to set the mark, M-f M-f to extend the selection forward two words, C-w to delete the selected region.
If you set the mark before beginning an incremental search, the search acts as a navigation command and extends the selected region. Exiting the search will leave the entire region selected from the place where you set the mark to the place where you exited the search. Note that this is not the default behavior for isearch-forward however.
just press ENTER to end the search.
if you mean that the selection area is displayed, you can unmark it with Ctrl-Space.
but I am not sure this answers your question.
--dmg
In Aquamacs 2.2 I could do the following:
1) Set the mark with C-SPACE
2) Click somewhere to set the point
Consequently this would define the region. Since Aquamacs-2.3 this behaviour is gone: A click sets both the mark and the point. Is there a way to customize aquamacs to have the old behaviour?
For Emacs 24, here's what worked for me (and may also apply to Aquamacs): Unset the binding for the <down-mouse-1> event, which is what is setting the mark (but not the point; the point is set by a different binding, for the up-event <mouse-1>).
That seems to provide the behavior you are asking for: clicking the mouse after setting the mark via C-space sets the point, and one can see the corresponding region highlighted.
I determined this by reading the help for the bindings above, by doing:
M-x helpkclick, and reading the *Help* text, which explains that <down-mouse-1> is bound to command mouse-drag-region (which sets the mark).
I then tested the resulting behavior by interactively disabling the binding, by doing:
M-x global-unset-key and then clicking; but it is probably much safer to do it programmatically, e.g. in the scratch buffer, by evaluating:
(global-unset-key [down-mouse-1])
If you like the behavior that results, then just copy the above line into your .emacs
Employing the solution described above does seem to cause mouse-dragging to be a little funky, in that it does not highlight the selected region during the drag (but you still get to see what the region is once you let go, and you can now fine tune its end point via single clicks, which may be useful in some circumstances.)
I decided that I was ready to try something new, after a few years of using gEdit for most of my coding needs, and try to learn using Emacs. I knew this would be difficult, as I have heard how complex Emacs can be, but I was lured by its power. The hardest thing has been getting used to writing ELisp in the .emacs file to change things about the editor. I can't currently do it myself, but I have found a few helpful snippets here and there to change some options.
One thing I have been having a lot of problems with is getting Emacs to remember the text I have selected after a command. For instance, I commonly highlight a section of code to mass indent it. However, if I do this in Emacs, it will move the selected text only once before unselecting all of the text. Does anyone know a way around this?
Anyway, I apologize for what seems to me to be an easy question, but after an hour of Google searching and looking around here on SO, I thought it was worth asking. I have a few more questions about Emacs, but I will save them and ask separately after I get this straightened out. Thanks!
UPDATE
A few people have asked about what mod I am using and what type of text I am entering. While I don't know much about Emacs modes, I am editing a pure text file at the moment. Something like this:
Hello, I am a simple text file
that is made up of three separate
lines.
If I highlight all three lines and hit TAB, I get this:
Hello, I am a simple text file
that is made up of three separate
lines.
This is great, however, if I use C-x C-x like some suggest below to reselect the text and hit TAB again, I get this:
Hello, I am a simple text file
that is made up of three separate
lines.
I hope this helps!
FWIW, here is the reason for the behaviour of your newly-added example. (I'm not 'solving' the issue here, but I'm posting it to demystify what you're seeing.)
This was determined with emacs -q which disables my customisations, so the following is default behaviour for emacs 23.2.
You are in text-mode. You should see (Text) or similar in the mode line at the bottom of the screen, and C-h m will tell you (under the list of minor modes) "Text mode: Major mode for editing text written for humans to read." Emacs decides (by way of the auto-mode-alist variable) that it should switch to text-mode if you visit a filename matching certain extensions (such as .txt).
In text-mode pressing TAB with a region highlighted causes indent-according-to-mode to be called on each line of the region in sequence. The slightly convoluted path to finding this out starts at C-h k TAB, which tells us that TAB is bound to indent-for-tab-command, which in this instance calls indent-region -- that function name is not stated explicitly in the help, but can be seen in the code -- which checks the buffer-local indent-region-function variable, which is nil, and: "A value of nil means really run indent-according-to-mode on each line."
indent-according-to-mode checks the indent-line-function variable, which has the buffer-local value indent-relative.
Use C-h f indent-relative RET to see the help for this function. (Read this).
Although you probably won't yet have had the experience to know how to check all that (or necessarily even want to!), and fully understand everything it tells you, this is an example of how the self-documenting aspect of Emacs enables a user to figure out what is going on (which then makes it feasible to change things). I essentially just used C-h k (describe-key), C-h f (describe-function), and C-h v (describe-variable) to follow the documentation. Looking at the source code for indent-for-tab-command was as simple as clicking the file name shown as part of its help page.
I suggest doing the following to help see what is happening when indent-relative runs on each line:
M-x set-variable x-stretch-cursor t
M-x set-variable ruler-mode-show-tab-stops t
M-x ruler-mode
Now for each line in turn, put the cursor at the very start of the line and press TAB. You'll end up with all three lines indented to the first tab-stop ('T' in the ruler).
Now repeat this -- again, ensure you are at the very start of each line, in front of the existing indentation.
The first character of the first line (which is currently a tab) is once again indented to the first tab-stop, as there is no preceding line for it to examine.
Next, the first character of the second line is indented to match the position of the first non-white-space character of the preceding line. Because the first character of the second line is also a tab, the actual text of the second line is pushed one tab further along.
The third line follows suit. Its first tab character is lined up with the first non-white-space character of the second line, with the same relative effect as before, giving you the final state in your example.
To emphasise, note what happens if you now put enter the line "a b c" above the existing lines, then move back to the start of the next line (what was previously the first line) and press TAB. The first tab character will now be indented in line with the 'b'. Provided that the indent-tabs-mode variable is true (meaning you have actual tab characters), then this will have no practical effect on the position of the words in the line, as 'indenting' a tab with spaces will not have an effect until the number of spaces exceeds the width of the tab (but that's another kettle of fish entirely!)
All this really means is that text-mode in Emacs doesn't behave the way you'd like it to in this situation. Other major modes can do completely different things when you press TAB, of course.
As is invariably the case with Emacs, things you don't like can be changed or circumvented with elisp. Some searching (especially at the Emacs Wiki) will frequently turn up useful solutions to problems you encounter.
Try typing C-x C-x after Emacs unselects it.
Then, instead of hitting tab (I never knew that tab does what you said! That's totally whacked.), do M-8 C-x C-i. Pity it's so many keys, but it ought to do what you want -- namely, shove everything over 8 columns. Obviously replace the M-8 with something else if you want some other number of columns.
What I usually do is simply type C-x C-x (exchange-point-and-mark) after a command that deactives the region.
How are you indenting, and in which mode?
The indentation rules in any programming mode should generally just get it right. (If they don't, that's probably more indicative that you want to configure the rules for that mode differently, but I suspect that's a different question which has been asked already).
If you're in text-mode or similar and just using TAB, then I can see the problem.
Note that if you're using indent-rigidly (C-x C-i, or C-x TAB which is the same thing) then you can repeatedly indent the same region simply by repeating the command, even if the highlighting has disappeared from view.
You can also use a prefix arg to indent-rigidly to make it indent many times. e.g. C-u C-u C-x C-i (easier to type than it looks) will indent 16 spaces (4 x 4, as the prefix arg defaults to 4, and it multiplies on each repeat). Similarly, M-8 C-x C-i indents 8 spaces. This is fine in some circumstances, and way too cumbersome in others.
Personally I suggest putting (cua-selection-mode 1) into your .emacs and using that for rigid indentation. Trey Jackson made a handy blog about it. With this, you can C-RET to start rectangle selection, down as many lines as you need, TAB repeatedly to indent the lines, and C-RET to exit the mode.
While the rectangle is active, RET cycles through the corners. For left-hand corners, typing inserts in front. For right-hand corners, typing inserts after. For the single-column rectangle, bottom counts as 'left' and top counts as 'right' for this purpose.
Trey's blog lists all the available features (or look in the source file: cua-base.el)
Be warned that indentation in Emacs is generally an unexpectedly complicated topic.
You can do this with something like the following:
(add-hook 'text-mode-hook (lambda ()
(set (make-local-variable 'indent-region-function)
(lambda (s e)
(indent-rigidly s e tab-width)))))
Then selecting a region and hitting TAB. will indent the region by a tab-width. You can then exchange point and mark with C-x C-x and hit TAB again to repeat.
I do, however, agree with the previous answers that suggest using indent-rigidly directly.
Is there an Emacs minor-mode (or piece of elisp code) that lets you selectively hide/show environments while in LaTeX mode? For instance, I would like to move to the beginning of a long \begin{figure} block, hit a keystroke, and have the contents of that figure environment hidden from view. Similarly with \begin{proof} and so on, and ideally even with \subsections.
Is this possible? I just tried hs-minor-mode, allout-mode, and outline-minor-mode, but most of them don't recognize LaTeX's environments, e.g. hs-minor-mode fails with "scan error: unbalanced parentheses". I would prefer not to have to enter explicit folding marks like {{{ as in folding-mode.
[Ideally it would be great if the folding were persistent, but I see that that question doesn't have an accepted answer yet.]
AUCTeX does folding: http://www.gnu.org/software/auctex/manual/auctex.html#Folding
A popular complaint about markup languages like TeX and LaTeX is that there is too much clutter in the source text and that one cannot focus well on the content. There are macros where you are only interested in the content they are enclosing, like font specifiers where the content might already be fontified in a special way by font locking. Or macros the content of which you only want to see when actually editing it, like footnotes or citations. Similarly you might find certain environments or comments distracting when trying to concentrate on the body of your document.
With AUCTeX’s folding functionality you can collapse those items and replace them by a fixed string, the content of one of their arguments, or a mixture of both. If you want to make the original text visible again in order to view or edit it, move point sideways onto the placeholder (also called display string) or left-click with the mouse pointer on it. (The latter is currently only supported on Emacs.) The macro or environment will unfold automatically, stay open as long as point is inside of it and collapse again once you move point out of it. (Note that folding of environments currently does not work in every AUCTeX mode.)
In order to use this feature, you have to activate TeX-fold-mode which will activate the auto-reveal feature and the necessary commands to hide and show macros and environments. You can activate the mode in a certain buffer by typing the command M-x TeX-fold-mode RET or using the keyboard shortcut C-c C-o C-f. If you want to use it every time you edit a LaTeX document, add it to a hook:
(add-hook 'LaTeX-mode-hook (lambda ()
(TeX-fold-mode 1)))
If it should be activated in all AUCTeX modes, use TeX-mode-hook instead of LaTeX-mode-hook.
Once the mode is active there are several commands available to hide and show macros, environments and comments...