Subject: Re: [boost] [phoenix] request for a mini-review. (Re: Phoenix as a Boost library)
From: David Abrahams (dave_at_[hidden])
Date: 2010-10-18 10:14:34
At Mon, 18 Oct 2010 07:40:21 +0200,
Thomas Heller wrote:
> Preprocessor code generation takes time, and the time it takes is significant.
> The most annoying fact is that even if we took care about not instantiating
> templates if the user doesn't want them, the user pays for these preprocessor
> iterations. Think about it, in the case of perfect forward emulation
> the number of
> overload created is O(N!). Even if N is large, the search for the
> right overload shouldn't
> be a problem (searching is in O(log(N))).
The answer for that is easy: preprocess the code yourself, the way MPL
does, for the minimum or default number of arguments you're going to support.
> >> As a side note, more and more Boost libraries are making compilation
> >> very slow, and it would be nice to integrate standardized PCH headers as
> >> part of the Boost distribution, which would be automatically generated
> >> at installation time.
> > Agreed.
> Instead of providing PCH headers, we could just preprocess our headers with some
> kind of boost.wave driver, like MPL already does.
-- Dave Abrahams BoostPro Computing http://www.boostpro.com