[Boost-users] help with regex library matching

From: Andrew Dennison (adenniso_at_[hidden])
Date: 2004-09-12 11:53:56

I have having a problem determining if the regex library is working 
properly.  I have run the regex regression tests, and all tests in the 
test.txt file pass. My problem however began with the following 
match:

string:          "orange and ba.ana and kiwi" 
expression:      "\\.([a-z]+).*[ \t\n].*\\.([a-z]+)"
expected result: match, captures 'range' and 'ana'
real result:     no match

The code in question is this:

    bool result = false;
    std::string str = "orange and ba.ana and kiwi";
    std::string exp(".([a-z]+).*[ \t\n].*\\.([a-z]+)");
    try {
      boost::smatch what;
      boost::regex e(exp.c_str());
      // use default format flags
      result = regex_match(str, what, e);
      if (result) {
        ...
      }
    } catch (std::runtime_error &e) {
      ...
    }
    ...

It seems to consistently fail.  This same example works in both Java and 
Perl, and with the PCRE C++ regex library.  No exception is being caught 
either.

I posted the actual code to show that i don't think i'm doing anything 
particularly unique - i call regex_match (though even regex_search fails 
to match).  I even tried formatting a file for the regression test 
harness with this example, and it confirmed that this particular example 
does not succeed. 

Can someone please provide suggestions regarding:
a) what is going wrong 
b) how to fix it

It should be noted that i'm running linux, boost version 1.31.0, with 
the regex patch installed.

Thanks.