id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
4103,erase_all_regex does not work well with possibly empty strings.,Paolo Bolzoni <bolzoni@…>,Marshall Clow,"Here is a test case, I want to remove all the substrings that matches the regular expression '`\s*`': all spaces, tabs and similars.

{{{
 $ cat test_case.cc 
 
 #include <boost/algorithm/string/regex.hpp>
 #include <iostream>
 #include <string>
 
 boost::regex const& spaces() {
     static boost::regex rv(""\\s*"");
     return rv;
 }
 
 int main() {
     std::string e1(""  Leading spaces!   Remove them   all!   "");
     std::string c1(e1);
     std::string e2(""No  trailing  or leading... Remove     them all!"");
     std::string c2(e2);
 
     boost::erase_all_regex(e1, spaces());
     std::cout << ""Erased:   -"" << e1 << ""-"" << std::endl;
     std::cout << ""Original: -"" << c1 << ""-"" << std::endl;
 
     std::cout << std::endl;
 
     boost::erase_all_regex(e2, spaces());
     std::cout << ""Erased:   -"" << e2 << ""-"" << std::endl;
     std::cout << ""Original: -"" << c2 << ""-"" << std::endl;
 }
 
 $ g++ -lboost_regex -W -Wall -pedantic -o test_case test_case.cc 
 $ ./test_case 
 Erased:   -Leading spaces!   Remove them   all!   -
 Original: -  Leading spaces!   Remove them   all!   -
 
 Erased:   -No  trailing  or leading... Remove     them all!-
 Original: -No  trailing  or leading... Remove     them all!-
 $
}}} 


I think the expected output should not have spaces in the output
string. Instead only the leading spaces are removed.

While the problem still persist with '`\s*`' the bug apparead also
with regex '`\s+`' in the version 1.41, but using the svn trunk
downloaded yesterday it disappeared. It is worth to note because the bug
is not very grave anymore. It is enough to use a regex that does
not allow empty strings.
",Bugs,closed,Boost 1.43.0,algorithm,Boost Development Trunk,Problem,wontfix,,