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Subject: Re: [boost] [logging] Interest check on logging library.
From: Gordon Woodhull (gordon_at_[hidden])
Date: 2009-01-04 05:05:59

On Jan 1, 2009, at 7:22 PM, Andrey Semashev wrote:
> Gordon Woodhull wrote:
>> I believe what Jason is talking about is compile-time filtering
>> where the compiler actually does know the answer and is able to
>> eliminate code. The "trivial 'if'" is gone after optimization.
>> This seems like a very nice feature to me.
> I agree that this is a very useful feature. One of my points in the
> reply to Jason was that there are simpler and more efficient ways to
> do it than employing metaprogramming and hoping that the optimizer
> does the rest.

I like the idea of expression templates for logging and find Jason's
syntax somewhat compelling, allowing different output to different
sinks from the same line. But I recognize that macros are going to be
the best solution for many projects, and it seems hard to match the
sureness that they'll completely compile away.

> Although lazy functions solve the problem, they complicate logging a
> lot. If you just want to put to log the result of a function call,
> you have to create a lambda expression or some functional wrapper
> for that call. I know, this is quite simple with Phoenix or Lambda,
> but this is still quite an amount of scaffolding for such a trivial
> task.

Yeah, it might be annoying to have to lazify every item that might
cost processor time!

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