Re: [Boost-users] question on boost::regex expression(query);

Variable length look-behind isn't support by Boost.Regex (or by Perl for that matter).

Sorry I can't be more helpful at present: although it seems as though lookbehind isn't really needed in this case - you could remove the lookbehind and use a marked sub-expression to identify the section you want instead.

The subexpression was the whole point of trying boost so I will assume you are right and continue. However, the inability to catch the problem with (...) combined with the linker comment made me a little concerned about the build accuracy. Thanks.

From: "John Maddock" Reply-To: boost-users@lists.boost.org To: Subject: Re: [Boost-users] question on boost::regex expression(query); Date: Tue, 2 Oct 2007 10:09:56 +0100

Mike Marchywka wrote:

...

...

Hi, I'm new to boost and not all that familiar with Perl regex. However, I have my own code for using Perl regex libraries for finding interesting features in DNA (

http://www.mail-archive.com/bio_bulletin_board@bioinformatics.org/msg01382.h...

...

)

I recently added boost to work along with Microsoft's greta code. However, I now have a problem with regex exploding. The questionable regex is presumably,

(?<=GU.*?TACTAAC.{20,40}AG|^).*?(?=GU.*?TACTAAC.{20,40}AG|$)

Variable length look-behind isn't support by Boost.Regex (or by Perl for that matter).

Sorry I can't be more helpful at present: although it seems as though lookbehind isn't really needed in this case - you could remove the lookbehind and use a marked sub-expression to identify the section you want instead.

So I think (?GU.*?TACTAAC.{20,40}AG|^)(.*?(?=GU.*?TACTAAC.{20,40}AG|$)) would be equivalent, with $1 containing the section you're interested in?

HTH John.

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