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Subject: Re: [boost] [regex] Support for Perl's (*SKIP)
From: John Maddock (jz.maddock_at_[hidden])
Date: 2015-04-19 06:55:35

> Without (*SKIP), it can be done only by calling regex::search multiple
> times, using an expression like this:
> (?-s)//.*+|/\*[\S\s]*?\*/|"(?:\\.|[^"\n])*+"|(\bfoo\b)
> and ignoring every match where group 1 wasn't matched. That's presumed
> to be slower, and certainly more inconvenient for the programmer.

I've added a bug report for this:

However, in the mean time, there is a much simpler workaround, if you use:

   (?x-s) (?# free spacing, dot doesn't match newline)
   (?://.*+ (?# eat single-line comment text)
     |/\*[\S\s]*?\*/ (?# eat multi-line comment text)
     |"(?:\\.|[^"\n])*+" (?# eat string text)
   ) (?# skip these)
   |\b(foo)\b (?# match this)

And if $1 matched, then you have what you were looking for, otherwise
discard. It's not as "neat" as the original, but is no less/more efficient.

HTH, John.

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