How do I highlight certain words between double quotes with font-lock?

Question

I'm trying to add additional colors to json-mode for when I edit json-schema. I can get it working fine without searching for double quotes, but I need to for some highlighting. I've tried quite a few things to highlight properties inside of "properties" including:

(font-lock-add-keywords 'json-mode '(("""\\(properties\\)""" 1 '(:foreground "chartreuse4") t))
(font-lock-add-keywords 'json-mode '(("\\""\\(properties\\)"\\"" 1 '(:foreground "chartreuse4") t))
(font-lock-add-keywords 'json-mode '(("\\s""\\(properties\\)\\s""" 1 '(:foreground "chartreuse4") t))

I expect once I understand the solution, I can easily highlight object in "type": "object" which was my original goal.

Answer 1

To put a " char inside a string in Lisp, just put one backslash in front of it.

If you want to highlight anything (not just properties) between double-quotes, try this as your regexp:

"\"\\(?:[^\"]\\|\\\\\\(?:.\\|[\n]\\)\\)*\""

That assumes that a backslash escapes any char - in particular the char ", so that \" is highlighted inside the string. Similarly for backslash preceding any other char. Dunno whether you want that, but you get the idea.