Re: [Boost-build] How to use generators to CPP and LIB

Subject: Re: [Boost-build] How to use generators to CPP and LIB
From: Alexander Sack (pisymbol_at_[hidden])
Date: 2009-01-30 12:29:06

On Fri, Jan 30, 2009 at 12:21 PM, Vladimir Prus <ghost_at_[hidden]> wrote:
> On Friday 30 January 2009 20:19:25 Alexander Sack wrote:
>> On Fri, Jan 30, 2009 at 11:10 AM, Vladimir Prus <ghost_at_[hidden]> wrote:
>> > On Thursday 29 January 2009 15:09:33 Duncan Rance wrote:
>> >> Hi there,
>> >>
>> >> I am trying to do something with generators but I'm stuck. I'd really
>> >> appreciate some help.
>> >>
>> >> What I've got so far is, in a module called resources.jam, something
>> >> like this:
>> >>
>> >> type.register RESTXT : txt ;
>> >> generators.register-standard resources.genenumh : RESTXT : H ;
>> >> generators.register-standard resources.pkgdata  : RESTXT : LIB ;
>> >>
>> >> What I need to do is use a .txt file to produce a header file and a
>> >> static library. The header file is to be used in a few places,
>> >> including the code used to create the LIB. But there's more to go in
>> >> the LIB than just the header. If you're interested, I'm using ICU's
>> >> resource bundling tools
>> >> (http://www.icu-project.org/userguide/ResourceManagement.html)
>> >>
>> >> As you can probably imagine, there is an ambiguity between
>> >> builtin.lib-generator and resources.pkgdata.
>> >>
>> >> How can I do this in boost build?
>> >
>> > I don't think there's a way to resolve this ambiguity without introducing
>> > custom generator class.
>> >
>> > I suggest you resolve the ambiguity using generators.override, in
>> > favour of your new generator. Your generator, however, should
>> > check if the source type is RESTXT. If so, it should build whatever you
>> > need. If the source type is different, it should call generators.construct
>> > for LIB target again, so that builtin generator does his job.
>> >
>> > I also recommend using some more specific extension than .txt
>>
>> After reading Volodya's email, I just realized is you are trying to
>> register one generator for two types!  Well one work around is the
>> name the same file with two different extensions which would allow two
>> different simpler generators no?
>
> The generator selection process does not use the types of the *sources*.

Good to know.  So how does the generator match then?  I would assume
strictly file name?

> I think one other approach is to create new type RESOURCE-LIB, derived
> from LIB, and register a generator creating RESOURCE-LIB. Then, given:
>
>        resource-lib a : a.txt ;
>
> there will be no ambiguity.

Will the generators chain in the correct order though?

Wow, well that is a very powerful capability of Boost-Build -
generator inheritance.  Volodya, there should be some example of this
in the Boost documentation cause that is very cool and I believe not
so uncommon.

-aps