Re: [jamboost] Re: target references

From: Vladimir Prus (ghost_at_[hidden])
Date: 2004-07-14 05:54:28

David Abrahams wrote:

> > Ah... I understand what you mean. No... the symbolic project id is always
> > absolute:
> > /boost
> > /boost/date_time
> >
> > or something like that. If you're in /boost/date_time, then you can't
> > refer to /boost by using ".." -- this is feature idea which never occured
> > to me.
>
> That's not what I mean.
>
> If boost has been given an absolute project ID of /boost, I want to
> be able to write something like:
>
> /boost/libs/python/test
>
> to refer to the python library's test project -- though I would strongly
> prefer to have a clear distinction between project path elements and
> filesystem path elements:
>
> [boost]libs/python/test
>
> or something

Ouch. It seems you're asking fore even more complex syntax. What we have now 
is:

1. Target-id is either file or target in Jamfile
2. If it's target in Jamfile, it can be in the current Jamfile, or elsewhere
3. If it's elsewhere, we can use either filesystem path to refer to location 
of other Jamfile, or its symbolic project id

What you propose that 
4. It's possible to refer to other Jamfile using first symbolic project id and 
then filesystem path relative from that.

I don't think I immediately like the latter idea because we'd really need some 
new syntax, e.g. [] that you've used. I think it's not that hard to specify 
ids like /boost/thread in individual library Jamfiles.

> In fact, for Boost in particular, it would be nice to be able to say
> something in a Jamfile about how to find its subprojects:
>
> rule subproject-path ( subproject-name )
> {
> return libs/$(subproject-name)/build
> }
>
> So that once [boost] is identified, [boost/python] automatically
> identifies the python subproject.

It would be nice, but I think manual specification is acceptable.

> > I'm not sure I understand. When looking up
> >
> > /boost/date_time
> >
> > in
> >
> > stage dt : /boost/date_time ;
> >
> > we first check if symbolic name /boost/date_time is known. If not, we try
> > looking at *directory* /boost/date_time and check if there's Jamfile in
> > that directory.
>
> You can't answer my question without considering paths with more
> elements:
>
>
> exe foo : /boost/foo/bar ;
>
> do you look for both /boost/foo//bar and /boost//foo/bar?

I don't understand. The /boost/foo/bar refers to *project*. Two other syntax 
refer to targets in some projects. There's no way they can be equal, and 
naturally I can't look for /boost/foo//bar.

Let me try again:

- we check if there's /boost/foo/bar/Jamfile file
- we check if there were some Jamfile which did

project /boost/foo/bar ; 

- Volodya