Re: [Boost-build] [bbv2] RFC: Repeated usage requirements.

From: Rene Rivera (grafik.list_at_[hidden])
Date: 2006-04-01 15:45:43

Jürgen Hunold wrote:
> Hi !
> 
> Am Maandag 27 März 2006, 10:11 schrieb Vladimir Prus:
>> Hi Rene,
> 
>> Like Dave, I'm a bit concerned about using <*> which means something
>> completely different in V1. Maybe, we can just use '*' without '<>'? Or
>> maybe, some keyword, like "usage". Using just '*' can look like black
>> magic.
> 
> What about naming the section (alike the "project") and then add a section 
> named "common-requirements" and be done ?
> This would add its entries to both "requirements" (better 
> "build-requirements" ?) and "usage-requirements".

After thinking on it for a few days that is certainly one viable route. 
Also the suggestion to use "build-requirements" for consistency is good. 
Perhaps that should be added as an alias for "requirements". With that 
in mind a few other possibilities spring to mind:

1. Use of build-requirements, usage-requirements, and 
common-requirements in one section instead of more sections:

lib foo : foo.cpp :
   build-requirements
   <define>COOL=1
   common-requirements
   <define>ENABLE_LOG=1
   usage-requirements
   <link>shared:<define>BUILD_DLL=1
   ;

2. Use of a conditional like syntax on the individual requirements to 
override the section:

lib foo : foo.cpp :
   <define>COOL=1
   common:<define>ENABLE_LOG=1
   usage:<link>shared:<define>BUILD_DLL=1
   ;

In that case the default is to use the section type. So for example one 
could put common requirements in the usage section:

lib foo : foo.cpp :
   <define>COOL=1
   : :
   common:<define>ENABLE_LOG=1
   <link>shared:<define>BUILD_DLL=1
   ;

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