Re: [Boost-build] Named metatarget parameters

Subject: Re: [Boost-build] Named metatarget parameters
From: Vladimir Prus (ghost_at_[hidden])
Date: 2010-03-06 04:27:17

On Monday 01 March 2010 18:45:57 Matthew Chambers wrote:

> On 2/28/2010 4:14 AM, Vladimir Prus wrote:
> > I am thinking of introducing named parameters to metatarget rules along the lines
> > of the following:
> >
> >     lib program_options
> >     : parsers.cpp
> >       [ requirements<link>static ]
> >       [ usage-requirements<define>BOOST_ALL_NO_LIB=1 ]
> >       [ default-build<variant>release ]
> >       [ description "Does something about dashes on command line" ]
> >       [ license "BSL 1.0" ]
> >     ;
> >
> > I expect the current syntax to remain available forever, but make this
> > new one the officially documented. You might note the example uses some
> > attributes ('description', 'license') that are not even  available now,
> > and in fact adding a pile of optional attributes is the primary goal
> > here.
> >
> > Internally, this will be implemented by introducing special classes
> > that are returned by rules like 'requirements' and specially processed
> > when encountered in the list of sources.
> >
> > Before I go and implement this, would anybody be willing to critizie
> > my experiments in DSL design?
> >    
> Named parameters would be a welcome feature! As would additional 
> optional parameters like you've listed here for description and license 
> (presumably these would become accessible in a build help system). 

The direct motivation is pkg-config support. But those can have many uses indeed.

> I 
> think your proposal has a decent syntax, but I agree with Johan that 
> sticking with the project rule syntax would be optimal. If that's not 
> feasible to implement, I'm happy with what you proposed. Would 
> conditionals work as well?

Which conditionals? Conditional requirements? Those should be unchaged.

Thanks,

--
Vladimir Prus
http://vladimir_prus.blogspot.com
Boost.Build: http://boost.org/boost-build2