std.logger

[Johannes Pfau]

Am Thu, 22 Aug 2013 20:04:16 +0200
schrieb Robert Schadek <realburner at gmx.de>:

> On 08/22/2013 07:48 PM, Johannes Pfau wrote:
> > The problem is that format allocates using the GC. Functions like
> > writefln can be much more efficient so if the backend is a
> > FileLogger it could take advantage of that. But IIRC it's not
> > simple to implement this 'forwarding' with classes / interfaces as
> > you'll need templated functions...
> yes, but as you said it is not simple. If it where a template the
> assignable default logger concept would not work,
> as it would instantiate the template of the base class. I don't think
> that this is possible (plz proof me wrong).
> IMO the default logger concept is more important.

I've implemented a small logger some time ago and IIRC I couldn't come
up with a satisfying solution.

The last std.log proposal made a compromise to deal with this: It
accepted formatted log input but it did call sformat internally before
passing it to the Logger implementation. The benefit of this was that
it could reuse the same buffer.

In (pseudo)code:

void logf(Args...)(string fmt, Args args)
{
    ubyte[BUFSIZE] buffer;
    _logger.log(sformat(buffer, fmt, args));
}