Unnecessary asterisk in regex that finds CSS comment
comments, css, regex, regex-negation
Solution
This has already been corrected in the CSS3 Syntax module:
\/\*[^*]*\*+([^/][^*]*\*+)*\/ /* ignore comments */
Notice that the extraneous asterisk is gone, making this expression identical to what you have.
So it would seem that it was simply a mistake on their part while writing the grammar for CSS2. I'm digging the mailing list archives to see if there's any discussion there that could be relevant.
Problem
I thought to ask this as an update to my previous similar question but it became too long. I was trying to understand a regex given in w3.org that matches css comments and got this doubt Why do they use ``` \/\*[^*]*\*+([^/*][^*]*\*+)*\/ ----------------^ ``` instead of just ``` \/\*[^*]*\*+([^/][^*]*\*+)*\/ ``` ? Both are working similarly. Why do they have an extra star there? Let's look at this part: ``` \*+([^/*][^*]*\*+)* -A- --B-- -C- ``` Regex engine will parse the A part and match all the stars until there is NO MORE stars or there is a line break. So once A is done, the next character must be a line break or anything else that's not a star. Then why instead of using `[^/]` they used `[^/*]`? Also look at the repeating capturing group. ([any one char that's not / or *][zero or more chars that's not *][one or more stars]) It captures groups of characters ending with atleast one or more stars. So C will take all the stars leaving B with no stars to match in the next round. So the B part won't get a chance to meet any stars at all. That is why I think there's no need to put a star there. But that regex is in w3.org so I guess my understanding may be wrong. Please explain what I'm missing.