Re: [Boost-users] [regex] difficulties with the "LeftmostLongest"Rule

From: John Maddock (john_at_[hidden])
Date: 2006-12-20 11:51:12

Detlef Meyer-Eltz wrote:
>> I know this wasn't what you were looking for, but I hope this
>> explanation
>> helps!
>
> Thank you, the truth always helps.
>
> A hint for you: there is another writing mistake: "that" instead of
> "than" in
> "Often there is more that one way of matching".

That'll be fixed in cvs in a moment: thanks for pointing that out.

> And the boost::regex::egrep option doesn't work. No match is found
> with:
>
> regex expression1("<[^>]*>\n<body([^>]*)>", boost::regex::egrep);

Yikes, that's a bad one to slip through, I'm testing (the fairly trivial) 
fix now.

> I guess, even a working egrep option would not change anything for me.

Nope, you need to either:

Use the perl-compatible expressions and place the alternatives in the order 
you want them searched,

or

Use POSIX expressions, and either put brackets around all the alternatives 
*and* put them in the order you want.  Or don't put braces around those of 
lower priority, and do put them around those of higher priority.

HTH, John.