[Boost-users] Regex question: is this a bug or a feature?

My pattern matching was failing when I had these definitions, which I happen to prefer: const string number = "[0-9]+"; const string name = "[A-z][A-z0-9]*"; ("name" is supposed to match a typical variable name) The program is working fine now, after I am using these ones: const string number = "\\d+"; const string name = "[A-z]\\w*"; The only difference that I aware of, is that the second form accepts underscores as part of variable names. TIA, -RFH