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From: David Abrahams (dave_at_[hidden])
Date: 2007-04-18 02:13:00

on Wed Apr 18 2007, Vladimir Prus <> wrote:

> On Sunday 15 April 2007 16:42, David Abrahams wrote:
>> Volodya and I have been talking about how target alternatives work
>> today in Boost.Build. We seem to agree that something is wrong with
>> them, but that's about all. We have different opinions about what's
>> most broken, and therefore different ideas what should be changed. We
>> would appreciate if members of this list help us by expressing their
>> opinions.
>> You can read my proposal at
> It appears that our discussion in this thread quickly goes into direction
> of comparing different analogies to the problems discussed. Before we
> get to far, I'd like to revisit some higher-level points.
> Dave, it seems like your proposal has three major aspects:
> 1. You claim that using one syntactic elements for both
> requirements and alternative selection is good.

Let's just say it's "not bad," and that it's extremely useful. I
don't believe anything can be called "bad design" on the basis of
principle alone. If there are negative consequences of that choice,
that's another matter.

> 2. You claim that it's often desirable to express
> "select this alternative is either <feature1>value1 or ...
> ... or <featureN>valueN" is in properties.

Yes, especially in the presence of prebuilt libs.

> 3. You claim that alternative selection should consider
> only explicitly specified properties.

Not exactly. I claim that explicitly specified properties should take
precedence over any property defaults when choosing alternatives. In
practice that might mean ignoring the defaults altogether, though.

Dave Abrahams
Boost Consulting
Don't Miss BoostCon 2007! ==>

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