Re: [jamboost] Re: [v2] header file conversion

From: Vladimir Prus (ghost_at_[hidden])
Date: 2004-12-27 10:18:39

On Monday 27 December 2004 17:37, alex76vs wrote:

> >   exe my_exe : a.cpp b.cpp : <implicit-dependency>my_header ;
> >
> > The "implicit-dependency" feature says that some of my_exe sources
>
> include
>
> > targets produced by my_header. V2 will figure out which one, and
>
> dependency
>
> > should be correct.
>
> This in an absolutely fantastic piece of functionality. How does it
> figure out that an additional "-I" should be added to locate a
> generated ".hpp" in the build output directory? This is more than I
> could expect!

It simply adds all target paths of main target referred by 
<implicit-dependency>. After that, bjam, during header scan, recognised that 
included target is the same that the generated one.

> Now I am passing some extra arguments to the generator in the
> following manner:
>     hpp b : b.h : <normalize-options>"abc def" ;
> In order to extract the arguments I use a loop:
>     rule normalize ( target : source : options * )
>     {
>         local args ;
>         for local opt in $(options)
>         {
>             if $(opt:G) = <normalize-options>
>             {
>                 args += $(opt:G="") ;
>             }
>         }
>         ARGS on $(target) = $(args) ;
>     }
> I suspect that there should be some utility class/function in the
> build system that would collapse all this into a single line. Is there
> anything?

Yes.

  flags your.generator.rule.name ARGS <normalize-options> ;

should do the trick. See

    http://boost.org/boost-build2/doc/html/bbv2/extending/features.html

- Volodya