I think the problem here is to say that you do NOT want bar in $1. Because if you wanted it, it may be easier :-)

Something like this should hopefully do want you want:

/foo(?!.*?bar.*?)(.*?)foo/;

[download]
You first try to find 'foo'. OK. Then you check if the substring between 'foo' and the other 'foo' contains 'bar', but with a zero-width assertion. If that does not contain 'bar', then you can save it into $1.

Thank you :-) thanks to your question I have understood why zero-witdh assertion is really cool!!

Hope this helps. Bye

James

Update: and what about doing:

/foo(?!.*?bar.*?foo)(.*?)foo/;

[download]
I think it is better, unless you show me another "worst case" :-))

In reply to Re: Regex'ing backreferences by zejames
in thread Regex'ing backreferences by Uruk

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