Regex, get only first occurrence and stop

Question

I'm trying to grab each individual keyframes declaration in a css file, and copy it, but inserting moz/ms/o to handle each browser with keyframes.

I'm using this regex:

(@)(-webkit-)([\s\S]*)(\}\R\}\R@)

To try and capture each collection (see full example at my Rubular)

What's your question? And what language are you doing this in? — Barmar, Oct 18 '13 at 01:10
I'm using common (Java/Ruby etc) regular expression terminology to recreate chunks of CSS so I don't have to write them by hand. — Riveascore, Oct 18 '13 at 01:12

score 2 · Accepted Answer · answered Oct 18 '13 at 01:23

2

Try this:

/(@)(-webkit-)(.*?\R\})/m

The m modifier makes it a multi-line regexp, so . matches across newlines. I removed the match for @ at the end, because then it can't match the last block in the file. And *? makes the match non-greedy, so it only matches one block at a time.

Rubular

answered Oct 18 '13 at 01:23

Barmar

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@Charlesism The OP's regular expression seems to assume very specific layout of the CSS, so I assumed he was working with a layout that he can ensure matches the expectations. Regular expressions are not good at matching balanced braces, so this is probably the best you can do. – Barmar Oct 18 '13 at 02:45

score 0 · Answer 2 · edited May 23 '17 at 12:05

The closest you get is...

(@-webkit-[^}]*}\s*to\s*{[^}]*}\s*})

...which can handle unusual/mangled indention in your CSS files decently. This is how it works:

( Start a capture group...
@-webkit- ...upon this phrase.
[^}]* } Continue until you you see a '}' character.
\s* to \s* { Next, the phrase ' to ', followed by '{'...
[^}]* } ...keep going till the next '}' character.
\s* } A final '}' character, possibly preceded by whitespace.
) Stop capturing.

It might be that there are cases where you have a false positive since regex doesn't understand nesting.

Regex, get only first occurrence and stop

2 Answers2