[dokuwiki] Re: back references in syntax plugin regex?
- From: Christopher Smith <chris@xxxxxxxxxxxxx>
- To: dokuwiki@xxxxxxxxxxxxx
- Date: Sun, 2 May 2010 21:35:47 +0100
On 2 May 2010, at 18:34, Simon Elliot wrote:
> Just a simple question for the experts out there: is it possible to use back
> references in a syntax plugin regex pattern? I'm trying to look for words
> with tripled letters at the beginning, i.e. the first 3 characters are the
> same, e.g. aaa bbb ccc, etc... I'm using the following regex, but it is not
> being recognised by the lexer:
>
> "\w\1\1\w+"
>
> Am I doing something wrong or is it just not possible?
>
Both. I think the pattern you're looking for requires the first letter in
parenthesis, so (\w)\1\1\w+. My recollection is the lexer only allows groups if
they are non-captured groups. This is because the lexer itself is a very large
compound regex and it uses the matching subgroup to determine which syntax is
being matched. FYI, you can use lookahead and lookbehind.
- Chris
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