[pmwiki-users] Re: Modified (:markup:)

[Joachim Durchholz]

Patrick R. Michaud wrote:

> On Mon, Mar 21, 2005 at 08:44:40AM +0100, Joachim Durchholz wrote:
> 
>> Patrick R. Michaud wrote:
>>
>>> I agree, but my implementation of [== ... ==] currently breaks in
>>> the face of text containing multiple [==]'s, so I have to either
>>> come up with a much better pattern or go back to the drawing
>>> board.
>> 
>> Would a backreference work?
>>
>>  \[(=*)[^=](.*?)\1\]
> 
> The matching code already uses a backreference and no it doesn't work.

Hmm... it *should* make sure that the same number of opening and closing 
equal signs is matched.

>> The (=*) captures the string of =s after the opening [ and stores
>> them in the $1 variable,  the [^= makes sure that a non-= is between
>> the brackest-and-equals-signs delimiters (else we'd match stuff
>> like [==] and we don't want that - might be a useful markup for
>> other purposes),
> 
> Unfortunately, [==] is already valid markup and it's already being
> used for a variety of purposes.  In particular, it can be used to
> prevent Wiki[==]Words, and I've used it to avoid processing something
> that would otherwise be a beginning of line markup.  Thus:
> 
>    [==]** Line beginning with ''asterisks'', avoid Wiki[==]Word.

Ah, so it's the reverse case: the pattern *should* match [==], [====], etc.

> Unfortunately, the regexp above (and various others I've tried)
> sees this as one big escape instead of two small ones, resulting in
> 
>    ]** Line beginning with ''asterisks'', avoid Wiki[Word.

My first idea would be this regex (spaces inserted for better readability):

   \[ (=*?) (.*?) \1 \]

It should eat the least number of equals signs and arbitrary text to 
make the match work.

Regards,
Jo