Parsing CSS background-image

Question

How do I parse CSS background-image, which supports multiple values, which may be none and functions (e.g. url() and linear-grad

Answer 1

Looking at the current W3C Candidate Recommendation for CSS3 (in particular, see background-image and uri), it is structured as follows:

 =  [ ,  ]* 
 =  | none
 =  |  |  |  | 

... (you can find the rest of syntax for images here)

EDIT:

You will need to parse for matching parenthese or none then, and the former is not possible with regex. This post has a pseudo code for the algorithm: Python parsing bracketed blocks.