On Sun, 31 Aug 2008 11:07:29 +0200, Andrey Semashev <andrey.semashev@gmail.com> wrote:
On Sat, 2008-08-30 at 23:16 -0700, Igor Nazarenko wrote:
By default, severity is printed as integer. What's the easiest way to print the corresponding string (e.g. "info" for severity 0, "warn" for severity 1, and so on)?
I tried defining operator<< for my severity enum, but attr<severity_level> doesn't work; that is, the output operator doesn't get invoked (I assume because attribute "Severity" is internally of type "int" and not of my enum type).
Yes, the severity level is stored as an int, and therefore the attr formatter uses operator<< for ints. Right now you can either define your own formatter that will accept an int and transform it into a string, or develop your own attribute and logger to store the level as an enum (then the attr formatter should be used with explicitly specified enum type).
I haven't decided yet how to solve this problem best in the library.
Igor, I'm also interested in your solution (as currently I'm also writing ints to my log files). I would prefer not to define a new logger though. While I like Andrey's logging library a lot I'm not so happy about having different logger types which I need to combine then somehow if I want to use the features of all those logger types (as it is done with severity_channel_logger which combines the severity_logger and the channel_logger; if we add more loggers we get dozens of combinations). I'm not sure either if this approach fits into Andrey's design. According to the definitions at http://boost-log.sourceforge.net/libs/log/doc/html/log/defs.html a logger is a log source (which is a good definition as it is easy to understand). But then it's a bit strange if you need to define a new logger only to customize the output? Maybe the decorator pattern could be used here (see http://en.wikipedia.org/wiki/Decorator_pattern for example)? Let's say you want to convert the severity int to a string. You'll define a decorator class and chain the decorator and the logger: logger log; my_decorator deco(log); BOOST_LOG(deco) << "Test"; The decorator behaves like the logger (same interface). It processes some attributes in open_record (like converting the enumeration to a string) before it forwards the call to logger::open_record. That would make it possible to process attributes without introducing new classes like my_decorator_logger, my_decorator_severity_logger, my_decorator_channel_logger, my_decorator_severity_channel_logger etc. depending on what features you need. Of course you could also combine decorators with: logger log; my_decorator1 deco1(log); my_decorator2 deco2(deco1); BOOST_LOG(deco2) << "Test"; Boris