Question

I have a regex which I hope means any file with extension listed:

((\\.cpp$)|(\\.cxx$)|(\\.c$)|(\\.hpp$)|(\\.h$))  

How to compare it in Qt against selected file?

Answer 1

Your actual RegEx itself doesn’t have double backslashes (just when you fit it into a string literal). And you’ll need some kind of wildcard if you want to use it to match full filenames. There’s a semantic issue of whether you want a file called just “.cpp” to match or not. What about case sensitivity?

I’ll assume for the moment that you want at least one other character in the beginning and use .+:

.+((\.cpp$)|(\.cxx$)|(\.c$)|(\.hpp$)|(\.h$))

So this should work:

QRegExp rx (".+((\\.cpp$)|(\\.cxx$)|(\\.c$)|(\\.hpp$)|(\\.h$))");
bool isMatch = rx.exactMatch(filename);

But with the expressive power of a whole C++ compiler at your beck and call, it can be a bit stifling to use regular expressions. You might have an easier time adapting code if you write it more like:

bool isMatch = false;

QStringList fileExtensionList;  
fileExtensionList << "CPP" << "CXX" << "C" << "HPP" << "H";

QStringList splitFilenameList = filename.split(".");  
if(splitFilenameList.size() > 1) {
    QString fileExtension = splitFilenameList[splitFilenameList.size() - 1];  
    isMatch = fileExtensionList.contains(fileExtension.toUpper()));
}