Question

In html major mode, Emacs is programmed to syntax highlight html character entity references (i.e., character references specified by name, e.g.,  ) but not, for some reason, numeric character references (e.g.,   or &#xa0). I guess this is a special case of the more general problem of customizing syntax highlight in a given mode. I imagine it involves some use of regexes. Can someone give me some guidance on how get started with this?

Answer 1

Following code snippet should help you:

(add-to-list 'sgml-font-lock-keywords-2 
   '("\\&#x?[0-9a-fA-F][0-9a-fA-F]*;?" . font-lock-variable-name-face))

but it should be put after loading of sgml-mode that provides html-mode. You can force loading with following command:

(require 'sgml-mode)