std.experimental.logger formal review round 3

[Kevin Lamonte via Digitalmars-d]

On Thursday, 2 October 2014 at 18:11:26 UTC, Marco Leise wrote:
> How would I typically log an exception?

We could add a Throwable reference in LogEntry and some 
overrides.  But how exception stack traces appear in the output 
(multiple lines, all-on-one line, e.msg only, following the 
chain, etc.) should not be firmly set here:  we can provide a 
reasonable baseline in FileLogger, but other Logger subclasses 
will definitely want to do different things.

Another issue is that in practice one will often want to log at 
debug an exception they are about to throw (libraries), but log 
at error anything they actually catch (applications).  Should we 
include those use cases too?  This skirts very close to the 
"policy, not mechanism" line, but might be worth it.

Proposal:

    LogEntry {
        ...
        Throwable throwable; /// Optional Throwable
        bool caught;         /// If true, then throwable was 
logged via caught/caughtf
    }

    void throwing(Throwable t, string msg) {...}
    void throwingf(Throwable t, string formatMsg, A... args) {...}
    void caught(Throwable t, string msg) {...}
    void caughtf(Throwable t, string formatMsg, A... args) {...}

Thoughts?