Std Phobos 2 and logging library?

[Steven Schveighoffer]

On Fri, 10 Apr 2009 12:20:46 -0400, Andrei Alexandrescu  
<SeeWebsiteForEmail at erdani.org> wrote:

> Zz wrote:
>> Hi,
>>  Are there any plans for a logging library in Std Phobos 2.0?
>>  Zz
>
> I wanted to add logging support for a while now but am undecided about  
> the API to use. Log4J is quite popular but quite complicated. There are  
> a number of simpler APIs out there but I couldn't figure out which is  
> the best.
>
> If anyone has ideas and/or code to contribute, that would be great.

Having experience with Tango's logger, here are the things I like about it:

1. lazy evaluation.  This is key, because it removes the whole requirement  
in log4* which requires you to check if the logger is active before doing  
some expensive calculation.  With lazy evaluation, you move the check into  
the log function.  BTW, this is a *HUGE* potential win for macros (if they  
are ever implemented), since you can get rid of the lazy eval.  See my  
post:  
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D.learn&article_id=12431
2. No heap activity.  This is to keep the logger from bogging down the  
program with memory allocations.
3. Thread safe.

Other than that, Tango's is pretty similar to log4* varieties.  I think  
the general design of log4* libs is pretty well tested and solid, but  
using some nifty features of D that can't be had in other languages makes  
it even more useful.  So I'd start with that design and see what can be  
improved.  Similar to how you approached algorithms (start with stl, see  
what d features can be applied to it).

-Steve