Re: [Boost-build] Named metatarget parameters

Subject: Re: [Boost-build] Named metatarget parameters
From: Matthew Chambers (matthew.chambers_at_[hidden])
Date: 2010-03-01 10:45:57

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). 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?

-Matt