Can I make tweaks to a color-theme per mode?

Question

I'm using Emacs 23.2.1 from Ubuntu 11.04. I've installed purcell's port of the Solarized color-theme, but I'd like to adjust some of the faces to make my Python buffers look more like the Solarized Vim screenshot. It's easy enough to edit the color-theme so that my preferred colors are always used, but that would also change them in C mode and I want to avoid that.

Specifically, here's the default setting for the builtin-face:

(font-lock-builtin-face ((t (:foreground ,green))))

In Python mode - and only Python mode - I'd like to use this instead:

(font-lock-builtin-face ((t (:foreground ,blue))))

I'd ideally like to make this change by patching some logic into the color-theme definition so that I can send my adjustments upstream with a note saying "this changes just the Python highlighting". Failing that, I'd settle for something in my init.el. I'd much rather have it packaged with the main color-theme, though.

Is this possible? Scratch that. This is Emacs; I know it's possible! But how can I do it?

Answer 1

This should be possible using Face Remapping. Even though you prefer to patch up the color-theme definition, I'd argue for putting something like the following lines into your init.el file, as it is a more "standard" way of doing such things:

(add-hook 'python-mode-hook 'remap-builtin-face-blue)

(defun remap-builtin-face-blue ()
  (let ((blue "#2075c7"))
    (set (make-local-variable 'face-remapping-alist)
         `((font-lock-builtin-face :foreground ,blue)))))