Re: Build properties algorithm

From: David Abrahams (dave_at_[hidden])
Date: 2004-03-23 00:26:42

Vladimir Prus <ghost_at_[hidden]> writes:

> Hello,
> for quite some time we had a couple of buggy corner cases in the algorithm 
> which computes build properties for a target
>
> 1. If a composite property had default value, then default value was added, 
> but not expanded.
>
> 2. Subfeatures in requirements were not expanded, so something like
>
> <toolset>msvc-6
>
> did not work quite right.
>
> So, I've decided to revise the algorithm a bit. The new version was just 
> comitted, which fixes the above bugs. It also makes requirements like:
>
> <toolset>gcc:<variant>release <variant>release:<define>FOO
>
> work in an intuitive way: i.e. FOO is defined.
>
> This version is not necessary final. I attach description of the algorithm 
> (which will be eventually added to docs) and will appreciate any comments.
> Of course, if the change breaks something or inpacts performance, I'd like to 
> know as well.

After a cursory look, seems very complete, and probably better than
what Ali and I came up with. Is there a provision for error checking
(e.g. finding conflicting properties?)

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com