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

Subject: Re: [Boost-build] How to use generators to CPP and LIB
From: Duncan Rance (gmane_at_[hidden])
Date: 2009-01-30 10:48:13

Thank you. This is really useful info. My case is slightly different
though, so I can't quite get the same kind of thing to work.

Alexander Sack wrote:
> Duncan, are you trying to do to create a header file that is used to
> build the lib or does the input file actually create a lib and an h?

Answer:
The input file actually creates the H and the LIB.

Let's say I have a file called root.txt. I've got one generator to
create resource_enum.h (H)  and one to create root.a (LIB). (I've just
realised that resource_enum.h is not actually needed to create root.a)

The problem is that the built-in generators know how to get from H ->
LIB, but I don't want them to try.

Not sure if this makes much more sense. I hope so :)

I think I'm going to try a different tack.

Regards,
Duncan

Alexander Sack wrote:
> On Fri, Jan 30, 2009 at 3:59 AM, Duncan Rance <gmane_at_[hidden]> wrote:
>> Hello again,
>>
>> Perhaps I'm missing something obvious or what I want to do isn't possible?
>>
>> Have I been clear in my description? The essential problem I'm trying
>> to solve is to use one source-type to produce two different
>> target-types. Where one target-type is H and is compiled into my
>> target exe, and the other is a LIB containing different code that is
>> ultimately compiled into the same exe.
>>
>> Is this even possible? Is this documented somewhere?
> 
> Duncan, are you trying to do to create a header file that is used to
> build the lib or does the input file actually create a lib and an h?
> 
> Let me share some code that I used as practice (with a little help
> from this list) to do this (using Google Protobuf's):
> 
> PROTO -> CPP
> PROTO -> H
> 
> I used the following generator, proto.jam:
> 
> import type ;
> import generators ;
> import feature ;
> import common ;
> import "class" : new ;
> 
> gPROTOC_CMD = [ common.get-invocation-command protoc : protoc ] ;
> 
> type.register PROTO : proto ;
> 
> class proto-generator : generator
> {
>     import "class" : new ;
> 
>     rule __init__ ( * : * )
>     {
>         generator.__init__ $(1) : $(2) : $(3) : $(4) : $(5) : $(6) :
> $(7) : $(8) : $(9) ;
>     }
> 
>     rule run ( project name ? : property-set : sources * )
>     {
>         if ! $(sources[2])
>         {
>             # Accept only single source.
>             local t = [ $(sources[1]).type ] ;
>             if $(t) = PROTO
>             {
>                 # If no output name is specified, guess it from sources.
> 		if ! $(name)
>                 {
>                     name = [ generator.determine-output-name $(sources) ] ;
>                 }
> 
>                 local a = [ new action $(sources[1]) : proto.protoc :
> $(property-set) ] ;
> 		local t = [ new file-target $(name).pb.cc exact : CPP : $(project) : $(a) ] ;
> 		local h = [ new file-target $(name).pb.h exact : H : $(project) : $(a) ] ;
> 
>                 return [ virtual-target.register $(t) ] [
> virtual-target.register $(h) ] ;
>             }
>         }
>     }
> }
> 
> generators.register [ new proto-generator proto.proto : PROTO : CPP H ] ;
> 
> actions protoc
> {
>     $(gPROTOC_CMD) --proto_path=$(>[1]:D) --cpp_out=$(<[1]:D) $(>)
> }
> 
> Alright, this will take a .proto file run protoc on it which generates
> both a C++ and header files.  I can then use these files in a target
> like this:
> 
> lib mylib : [ glob *.proto ] : <include>. ;
> 
> This will run protoc on the .proto file and generate the C++ and
> header files, compile, link, etc.
> 
> I can also use the header from this build by doing when building a
> binary (this might be what you are trying to do with the lib):
> 
> exe myexe : [ glob *.cc ] : <include>. <implicit-dependency>/mproject//mylib ;
> 
> This will include the header file I generated from above in the linking process.
> 
> Does any of this help?  :D
> 
> -aps
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