I am using Emacs 24.3 and ESS 13.05 with the theme tangotango.el. While the theme is restful on the eyes, variable names in R don't appear to be highlighted. In tangotango-theme.el I can find the following line:
`(font-lock-variable-name-face ((t (:foreground "tomato"))))
but this doesn't appear to have any effect. For example, in the screenshot below I would expect the variable orl to be highlighted in some shade of red. Instead it is the standard text colour for this theme.
If I delve into ESS there is a file named ess-font-lock.el which contains a few references to the variable name face, like this one:
(set-face-foreground 'font-lock-variable-name-face "Black"))
So it looks as if font-lock-variable-name-face has competing definitions. I don't understand the interaction between Emacs themes and these ESS definitions. Is ESS overriding the tangotango theme and if so, will changing the above line in ess-font-lock.el restore variable name highlighting? Or should I be looking somewhere else entirely?
Edit: note that Cperl mode does seem to respect the font lock:
You are looking in a wrong place. ess-font-lock defines themes. Some 10 years ago that was useful. Now there are generic themes like your tango-tango and ESS doesn't interfere with them.
The issue is that ESS does not define a font lock keyword that you are looking for. The reason is that <- is an assignment operator, and there is no an explisit variable definition statement in R. ESS only treats function definitions. That is, assignment of a function will be highlighted:
foo <- function(){}
Believe me or not, but you really don't want to highlight all your assignments. You can try it though with:
(defvar ess-R-fl-keyword:assign-vars
(cons "\\(\\(?2:\\s\"\\).+\\2\\|\\sw+\\)\\s-*\\(<-\\)"
'(1 font-lock-variable-name-face)))
(add-to-list 'ess-R-font-lock-keywords '(ess-R-fl-keyword:assign-vars . t) t)
ESS implements a flexible font lock customisation mechanism on top of emacs font-lock system. See ESS>font-lock submenu.
Yes, it sounds like it. If you see the problem only in that mode, and that mode explicitly changes the face, then that sounds like the culprit. You should not need to change the source code, however. Just do something like this (untested):
(add-hook 'ess-mode (lambda () (set-face-foreground "tomato")))
(I assume that's the right mode name; if not, correct it.)
But this is an ugly workaround -- you should not need to do that. Consider filing a bug against the ess-mode.el code. It should not trample on user settings such as faces that way. If it wants to change the appearance by default then it should give users a new face that they can customize, instead of simply screwing with an existing face in a hard-coded way.
Related
I have opened a buffer with some text on 100 lines.
I would like to change the color of my cursor to red when I reach the row 90?
How would such Elisp function I could put in my init file look like?
Let's say the hook should work for all modes, for simplicity.
Disclaimer: I did not know how to do that before answering. I will tell you how I did find the solution using Emacs.
You can change the colour of the cursor by changing the :background attribute of the cursor face (as seen when using describe-face, or by reading the "Cursor Display" section of the Emacs manual - which is built-in and can be read from Emacs)
I am not aware of a "good" hook that could be used to do this, though. An idea could be to use post-command-hook, but it might be slow.
A (possibly, and probably bad, not thoroughly tested) solution:
(defun my/switch-cursor-color ()
(if (< (line-number-at-pos) 90)
(set-face-attribute 'cursor nil :background "#abcd12") ;; hex-code for your colour
(set-face-attribute 'cursor nil :background "#1234ef")))
(add-hook 'post-command-hook 'my/switch-cursor-color)
Of course, to be safe, you should probably do other checks (what happens in pdf-view-mode/doc-view-mode, etc), but this "should work".
How to get all this information:
Inside Emacs:
C-h i opens the Info directory
Navigate (or use m) to the Emacs one
Press i and search for cursor, or search in the Index directly, or search with s the "cursor" regexp ... until you find the "Cursor Display" section. If you forgot how to do that, as usual in this kind of mode, try pressing h, or ?, or C-h m (they don't necessarily do the same thing, but are all helping you)
In this node, you find that
To customize its color, change the ‘:background’ attribute
of the face named ‘cursor’ (see Face Customization).
Click on the "Face Customization" link to view how to do it via the "Customization Interface". To do it programmatically (i.e. as I did above, using the set-face-attribute function), repeat the steps above to view how to do it.
You can also use the function set-face-background, a simple wrapper around set-face-attribute. To discover this function, you can (and should) also use Emacs: a proper completion/selection system, or the function apropos-command, bound to C-h a, with e.g. the search "face background", and the aforementioned function is then immediately found.
Aaaand if you forgot how to look for help, then use C-h C-h. This command is shown in the tutorial, itself accessible from the menus, or from the initial buffer when starting Emacs (by default), or ... etc.
I want to color some specific command and tactic into different color, e.g. I want "Print" and "Locate" command to be gray, and "induction" to be some special color different from other tactics.
Is this possible in ProofGeneral? If it is not configurable in ProofGeneral, then is it possible to configure it via some Emacs mechanism ?
PS: I have checked the manual of ProofGeneral, but cannot find any related option.
As far as I know, this is not possible in ProofGeneral. However, you can customize the colour of keywords by changing their face in emacs.
To do this, move the cursor to the word you want to change and then press M-x and enter customize-face, which will bring you to the customization window.
To add keywords to the ProofGeneral minor mode, you may want to have a look at https://www.gnu.org/software/emacs/manual/html_node/elisp/Customizing-Keywords.html
This adds the induction keyword with the font-lock warning face
(add-hook 'coq-mode-hook
(lambda ()
(font-lock-add-keywords nil
'(("\\<\\(induction\\):" 1 font-lock-warning-face prepend)))))
Update:
Note that this thread does not applyt o recent versions of Emacs (24+). Emacs now comes with it's own powerful color theming system (e.g. see a review here) that does not required loading the external package color-theme .
I have the following code snippet in my .emacs file, where I defined a few aliases that allow me to switch conveniently between a couple of color themes using short extended commands:
(require 'color-theme)
(eval-after-load "color-theme"
'(progn
(color-theme-initialize)
(color-theme-aalto-light)))
;; Aliases to color-themes, e.g. 'M-x a' switches to color-theme-hober
(defalias 'a 'color-theme-hober)
(defalias 'b 'color-theme-aalto-light)
Now, when Emacs loads, it displays the color-theme-aalto-light theme properly, and, when I M-x a to change to color-theme-hober, that works too.
The problem is when I try to change the color theme back again to color-theme-aalto-light. Some color faces remain in the old color-theme while others are changed to the new color theme. I have tried with different color theme combinations with no luck (the color faces are not always fully updated, regardless of the color-themes I switch between). Any thoughts?
This is a known bug in 'color-theme' package. If that feature is important for you, consider upgrading to trunk (future emacs-24.1), it natively supports changing themes (M-x customize-themes).
colour themes are basically just functions, which assign new colours to certain faces. There is nothing special about them, especially faces are not reset before switching colour themes. If one colour theme A sets a colour for a certain face, and another B does not, then B will simply take over the colour defined by A for this face.
This is more or less by design, and there is nothing, you can do about, save modifying the colour themes to cover all defined faces (which is rather tedious, and also quite impossible, because any elisp library can define its own faces).
Suppose I have a few words I would like to highlight, so I want to change the color of those few words only to, say, green.
Is there an easy way to do this in emacs?
Thank you.
This is what I've done, using font-lock-add-keywords. I wanted to highlight the words TODO:, HACK:, and FIXME: in my code.
(defface todo-face
'((t ()))
"Face for highlighting comments like TODO: and HACK:")
(set-face-background 'todo-face cyan-name)
;; Add keywords we want highlighted
(defun add-todo-to-current-mode ()
(font-lock-add-keywords nil
'(("\\(TODO\\|HACK\\|FIXME\\):" 1 'todo-face prepend))
t))
Use library HighLight. You can use overlays or text properties. You can save the highlighting permanently or let it be temporary. You can highlight in many ways (regexp, mouse-drag,...). Lots of possibilities.
The highlight package has hlt-highlight-regexp-region and hlt-highlight-regexp-to-end, which do exactly what you want.
http://www.emacswiki.org/cgi-bin/wiki/highlight.el
Use the function font-lock-add-keywords to define a new matcher for the string in question, binding that matcher to some face you've defined that will display as green. For example:
(font-lock-add-keywords nil
'("\\<foo\\>" 0 my-green-face))
Note that you can specify a particular mode where I wrote nil above, and the matching forms can take on any of six different styles. See the documentation for the variable font-lock-keywords for the rules and a few examples.
If you want them highlighted only temporarily, I find M-x highlight-regexp command very helpful, it is especially nice for looking through log files of sorts. For example you made yourself a logging class that outputs some tracing info like MyClass::function() > when function is run and MyClass::function() < when it exits (can be especially useful sometimes when debugging multithreading issues) then you just ask emacs to highlight some of them green and other red and then you can see how did the execution go.
I use what Dimitri suggested. In particular, I have the following two lines in my .emacs
(global-hi-lock-mode t)
(global-set-key (kbd "C-M-h") 'highlight-regexp)
Every-time I need to highlight a certain word (or regex) in a buffer, I hit "C-M-h", which then prompts me for the word (or regex) I want to be displayed differently and then for a face to display it in.
The Emacs cperl-mode seems to get confused less than perl-mode, but the Skittles effect makes the thing unusable for me. Does anyone have or know of an example of a .emacs block that causes cperl-mode to use the colorization from perl-mode, ideally in a form readable enough that I can go back and turn back on the default colors one element at a time until I reach something I'm comfortable with?
In particular there is a hideously shade of light green used for some builtins that I find quite unreadable, and I prefer my variables to not have the leading $ and $$ and such tinted red along with the variable name. Most of the rest are merely distracting.
Press M-x customize-group RET cperl-faces RET and change coloring to your liking.
With colour themes, the problem is limited to arrays and hashes - and it turns out that that's because cperl-mode defines those faces as being bold-weight, which colour themes don't appear to affect (Solarized doesn't).
In Emacs 23.3 on Mac OS, the following restored the colours to how the colour theme defined them:
(custom-set-faces
'(cperl-array-face ((t (:weight normal))))
'(cperl-hash-face ((t (:weight normal))))
)
You can also use the 'real' perl-mode coloring by overwriting font-lock settings with those of perl-mode.
(require 'perl-mode)
(add-hook 'cperl-mode-hook
(lambda ()
(setq font-lock-defaults
'((perl-font-lock-keywords perl-font-lock-keywords-1 perl-font-lock-keywords-2)
nil nil ((?\_ . "w")) nil
(font-lock-syntactic-face-function . perl-font-lock-syntactic-face-function)))
(font-lock-refresh-defaults)))
You can change the color theme if you don't like the particular default colors.