[Boost-users] tabs and newlines in Regex character ranges

From: David McKelvie (david_at_[hidden])
Date: 2005-03-24 16:41:28

As an aside:

with the following match values

  boost::regex_constants::match_flag_type mflags = 
    boost::match_default |
    boost::match_not_dot_newline |
    boost::match_continuous ;

The following is an irritating feature of the regex package

expression.assign("[ \t\n]", boost::regex::extended);

does not match tab or newline

expression.assign("[ \t\\n]", boost::regex::extended);

does not match tab or newline

expression.assign("[ \\t\\n]", boost::regex::extended);

does not match tab or newline

The full expression I'm using is

  expression.assign("(keyword)|([a-zA-Z][a-zA-Z0-9_-]*)|([ \\t\\n]+)|([0-9]+)|(\"[^\"]*\")|(.)", sflags);
                                                         ^^^^^^^^^
Presumably I need to set
           regbase::escape_in_lists

but why arent TAB and NL allowed as raw characters in character ranges?

    David