Display consecutive whitespace as dots in Emacs - emacs

This answer nicely provides a way to display characters rather than tabs (in the example it suggests ">", but I confirmed it works for ".").
It uses setting the active window display table to do it.
Now my goal is to display 4 spaces as 4 dots. Using the font-face and a regular expression, I am confident that I can display it nicely. I am aware that I could have Emacs automatically use tab characters rather than whitespaces, but I always prefer to have whitespace characters in my files.
I've also looked at whitespace mode, but I tweaked many parameters and in the end I never get the simple dots (with a face that makes it a little less "jump" out).
So: how can I, rather than display tab characters as dots, display 4 spaces elegantly as dots in Emacs?

OK, here's how to mark 4 or more spaces at beginning of line
(setq whitespace-space-regexp "^\\( \\{4,\\}\\)")
And here's how to get rid of the centered dot character for space:
(setq whitespace-display-mappings
'((space-mark ?\ [?\ ] [?.])
(space-mark ?\xA0 [?\ ] [?_])
(newline-mark ?\n [?$ ?\n])
(tab-mark ?\t [?\u00BB ?\t] [?\\ ?\t])))
The changes take effect not immediately but when you revert-buffer or
close it and open again with customizations above already set.

Related

Tab stops are messed up after rarer unicode characters

In vscode, when I open a file containing unicode characters,
I notice that tabs do not always advance to the next tab stop.
For example, the following might be part of an ASCII-flavor table
a<tab>b<tab>c<tab>d<tab>e
α<tab>β<tab>γ<tab>δ<tab>ε
𝔸<tab>𝔹<tab>ℂ<tab>𝔻<tab>𝔼
While sublime text renders it correctly(IMO)
vscdoe has a different idea
As I understand it, vscode renders a tab by
replacing it with a proper number of space characters.
So if there are characters showing using proportional fonts,
no integer number of spaces will make it to the proper stop.
(See this related issue.)
So my question is, how can I fix this?
Is it possible to tell vscode that
"Fine, if you were to assume that those unicode characters
are 2 spaces wide when tabbing,
would you please render them as 2 spaces wide?"

Emacs highlighting: how to deal with highlighting messed up by unusual usage of special characters?

Problem:
In Emacs configuration modes (e.g. conf-xdefaults-mode or conf-space-mode), some special characters are used in unusual ways, for instance when they define keybindings. This messes up the highlighting for the rest of the buffer.
Example:
The ranger rc.conf file uses conf-space-mode which greatly helps its readability. But lines such as:
map # console shell -p%space
map "<any> tag_toggle tag=%any
mess up the highlighting since # usually defines a comment and is followed by font-lock-comment-face until the end of the line and " defines the beginning of a string and is followed by font-lock-string-face until it encounters a closing quote.
Escaping those characters is not an option because it would prevent them from defining the keybindings.
Possible solution:
The best solution I can think of is to fiddle with font lock settings for those configuration modes to remove the highlighting after those special characters. But I will then loose the proper highlighting after those characters when it is suitable.
A compromise could be to keep highlighting after # since this only messes up one line and there are a lot of comments in those configuration files, while removing the highlighting after single and double quotes since those mess up the entire rest of the buffer and strings are not so common in configuration files.
Question:
What is the proper way to deal with these situations?
Is there a way to reset the highlighting at a point in the buffer? or to insert a character which would affect the highlighting (to fix it) without affecting the code? or is there a way to "escape" some characters for the highlighting only without affecting the code?
The easy way
It's probably easiest to just live with it but keep things constrained. Here, I took ranger's default rc.conf and re-arranged some of the font-lock errors.
Let's ignore the blue "map" for now. We have two visible font-lock errors. The map #... is font-locking as a comment, and the map "... font-locking as a string to the end of the buffer. The first error is self-constrained. Comments end at the end of the line. The second error we constrain by adding a comment. (I don't know if ranger would accept comments in the middle of the line, so I'm only using beginning-of-line comments here.)
The second error is now constrained to one line, but a couple more errors have popped up. Quickly adjusting these we get.
This is something that I could live with, as I'm not in conf files all day long (as opposed to say, source code.) It would be even neater if our new "comments" could be included on the same line.
The hard way
You'll want to use Emacs font-lock-add-keywords. Let's get back to that blue map in the first image. It's rendering blue because conf-space-mode thinks that a string, followed by any amount of whitespace, followed by an opening brace should be rendered in font-lock-type-face (the actually regexp that triggers this is ^[_space__tab_]*\\(.+?\\)[_space__tab_\n]*{[^{}]*?$ where _space_ and _tab_ are actual space and tab characters.)
We can override this in a simple fashion by evaluating
(font-lock-remove-keywords
'conf-space-mode
'(("^\\<\\(map\\)\\>" 1 font-lock-variable-name-face)))
and reloading the buffer with C-x C-v RET. Now, every time that the word "map" appears at the beginning of a line it's rendered as font-lock-variable-name-face (yellow in our example.)
You can make this change permanent by adding a hook to your init file.
(add-hook 'conf-space-mode-hook (lambda ()
(font-lock-remove-keywords
nil
'(("^\\<\\(map\\)\\>" 1 font-lock-variable-name-face)))))
This method doesn't appear to work for your comment (#) and string (' ") delimiters as they're defined in the syntax table. Modifying the syntax table to provide special cases is probably more effort than it's worth.

Org-Mode Inline Code with Equals Signs

In org-mode, I want to give inline code with equals signs and quotation marks:
<div class="foo">
The way I would normally do this in org-mode is
=<div class="foo">=
When I export this to HTML, it gets rendered like this:
<div class"foo">=
What is the right way to do this inline (rather than just creating a source block)?
You could use verbatim markers, ~, instead:
~<div class="foo">~
The problem is that the equals sign after 'class' is interpreted as the closing code section delimiter. You can prevent this by inserting a space before the equals sign, like this:
=<div class = "foo">=
I wanted org-mode's source code to appear correctly in Github's parser. But, just as =:echo "hello"= would not appear correctly in Emacs, it also did not appear correctly in Github. However, I tried other characters with C-x 8 RET, and the LEFT DOUBLE QUOTATION MARK and RIGHT DOUBLE QUOTATION MARK work. That is,
=:echo “hello“=
appear successfully as
:echo “hello“
Unfortunately, I don't think they will actually work if copy-and-pasted into all environments. Vim gives E15: Invalid expression: “hello“. But then, how often do we paste commands into Vim's command line. Well, okay, there is :#".
After almost a decade, here's the correct answer:
Org's escape character is zero width space. When this character is inserted, Emacs will not interpret = as the end of the verbatim. Emacs can correctly interpret =<div class​="foo">=. Note that this string has an invisible zero width space character.
However, I think due to a bug, exports from org to other formats, will have this character and need to be removed manually. For example, the export of the string above to markdown will be `<div class​="foo">` which is what we want, except that it has an additional zero width space character.
It is not very hard to fix this. Removing all these additional characters can be easily done with replace-string command.
Tip: You can use C-x 8 RET (or insert-char command) and choose 200B to insert zero width space character inside Emacs.

Show trailing whitespace on emacs only on non-empty lines

Right now I'm using:
(setq show-trailing-whitespace t)
In my .emacs to show trailing whitespace for my CC mode. I can't seem to figure out how to have it not show the whitespace font for whitespace only lines.
Empty lines separating indenting code are sometimes indented at the code level and sometimes not indented at all, and I don't want to draw my attention to a line I don't care to change.
I'd like to stick to built-in emacs modules, but I'm willing to use whitespace.el but it's not clear how to configure it to do this.
Since you want to use built-in modules, I'd advise using the whitespace.el link you specified - as it is shipped with Emacs 23. This answer works when using that whitespace.
As long as you have 'trailing in your 'whitespace-style variable (which it is by default), the following change to the regular expression for what indicates "trailing" whitespace should give you what you want:
(setq whitespace-trailing-regexp
"\\b\\(\\(\t\\| \\|\xA0\\|\x8A0\\|\x920\\|\xE20\\|\xF20\\)+\\)$")
Note: It is just the default value, with the \b prepended, indicating that the whitespace should follow a word.
With
"\\b.*\\(\\(\t\\| \\|\xA0\\|\x8A0\\|\x920\\|\xE20\\|\xF20\\)+\\)$"
the word does not need to be directly in front of the trailing whitespaces but there can be e.g. punctuation characters between them (i.e. this also highlights trailing whitespaces behind non-word characters).
Edit:
Using
"\\b.*?\\(\\(\t\\| \\|\xA0\\|\x8A0\\|\x920\\|\xE20\\|\xF20\\)+\\)$")
highlights all the trailing whitespaces and thus eliminates the drawback mentioned in comment #1.

How to make part of a word bold in org-mode

How can I make org-mode markup work for a part of a word? For example, I'd like it to work for cases like this:
=Class=es
and this:
/Method/s
Based on my tests it seems like org-mode markup syntax works on complete words only.
These days, there is a way to do this (without using quoted HTML tags):
(setcar org-emphasis-regexp-components " \t('\"{[:alpha:]")
(setcar (nthcdr 1 org-emphasis-regexp-components) "[:alpha:]- \t.,:!?;'\")}\\")
(org-set-emph-re 'org-emphasis-regexp-components org-emphasis-regexp-components)
Explanation
The manual says that org-emphasis-regexp-components can be used to
fine tune what characters are allowed before and after the markup characters [...].
It is a list containing five entries. The first entry lists characters that are allowed to immediately precede markup characters, and the second entry lists characters that are allowed to follow markup characters. By default, letters are not included in either one of these entries. So in order to successfully apply formatting to strings immediately preceded or followed by a letter, we have to add [:alpha:] (which matches any letter) to both entries.
This is what the calls to setcar do. The purpose of the third line is to rebuild the regular expression for emphasis based on the modified version of org-emphasis-regexp-components.
I don't think you can do it so that it shows up in the buffer as bold. If you just need it so that it appears bold when you export it to html, you can use:
th#<b>is is ha#</b>lf bold
See Quoting HTML tags
No, you can't do that. I searched for the same solution before and found nothing. A (very) bad hack is to do something like *Class* es (with a whitespace).
Perhaps you can write a short message to the creator, Carsten Dominik (Homepage), and ask him for a solution. He seems to be a nice guy.
A solution that has not been mentioned is to use a unicode zero width space (U+200B) in between the desired bolded and unbolded parts of a word.
To get the desired bolding of the word "Classes":
Type 'Class*es' in the buffer (without quotes).
Move the cursor between the '*' and 'e' characters.
Press C-x 8 RET (to execute the insert-char command).
Type 'zero width space' (without quotes) and press RET.
Move the cursor to the beginning of the word and insert a '*' character.
The word "Classes" should now have the desired appearance.
Note that there is the possibility that this will cause problems when exporting.
src_latex{\textbf{Class}es and \textit{Method}s}
Building up on the previous excellent answer
I had to modify it a bit in order to make it work with spacemacs. Indeed, from the spacamacs org-layer documentation, available here, we can read
Because of autoloading, calling to org functions will trigger the
loading up of the org shipped with emacs which will induce conflicts.
One way to avoid conflict is to wrap your org config code in a
with-eval-after-load block [...]
So, I put the following lines inside my dotspacemacs/user-config ()
(eval-after-load "org"
'(progn
(setcar org-emphasis-regexp-components " \t('\"{[:alpha:]")
(setcar (nthcdr 1 org-emphasis-regexp-components) "[:alpha:]- \t.,:!?;'\")}\\")
(org-set-emph-re 'org-emphasis-regexp-components org-emphasis-regexp-components)
))