Re: [Boost-users] [regex] - Bug in boost::regex ??

30 Aug 2006

      Taking a quick look at the docs, the regex you want is:

"Resurfacing(.*?)Home"

Just a thought.  Seems like quite the thread for a regex pattern.

And like John says, it should match from the first Resurfacing to the second
Home.  If it didn't, I'd be concerned.

The * operator by itself is greedy.  It wants to make matches as long as
possible. By using the *? notation, it makes it a non-greedy modifier, ie,
making the match as short as possible.

http://www.boost.org/libs/regex/doc/syntax_perl.html
Under the heading 'Non greedy repeats' pretty much explains things.

(Note: This applys to the perl style regex, I'm not entirely sure about the
other behaviors.)

Cheers,
Paul

On 8/30/06, John Maddock  wrote:
...
kiran wrote:
...
Why is the second one not picked ? This was my question.
It is picked for me: I modified your sample program (see below) so that it
actually compiled, and didn't reply on external files, and I see exactly
the
output expected: everything from the first "Resurfacing" to the last
"home".
#include "boost/regex.hpp"
using namespace boost;
using namespace std;
#include
#include
#include <iostream>
int main()
{
char buf[10000];
//int fd = open("glass.htm", O_RDONLY);
//int size = read(fd, buf, 10000);
string line = "\n"
"<html><head>\n"
"<title>UGlassIt Fibre-Shelkote Pool Resurfacing for Swimming
Pools</title>\n"
"Home\n"
"Home";
//close(fd);
regex expr("Resurfacing(.|\n)*Home" , boost::regex::icase |
boost::regex::perl);
try
{
sregex_iterator itr(line.begin(), line.end(), expr,
boost::match_not_dot_newline);
sregex_iterator i;
while(itr != i)
{
cout<
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Re: [Boost-users] [regex] - Bug in boost::regex ??

Paul Davis