Re: [v2] ALL_LOCATE_TARGET capability?

From: David Abrahams (dave_at_[hidden])
Date: 2004-12-14 12:09:37

Vladimir Prus wrote:
> On Friday 10 December 2004 20:59, David Abrahams wrote:
> 
>> >> I thought of that. Here are several solutions that can be used
>> >> together:
>> >>
>> >> 1. keep a record of the directory of each project that was used to
>> >> build into a given target directory. Issue a prominent warning or
>> >> error if that directory changes, with instructions about deleting
>> >> the marker file.
>> >
>> > Ouch. The implementation might get contrived.
>>
>> C'mon, that's *easy* to do, and reasonable as well. The marker file can
>> just contain Jam code. You import it and you're done.
> 
> So, after computing build dir location for a project, we'll load something 
> from there and check if two project location --- current and recorded in a 
> file? That seems possible.

Precisely.

>> >> 4. Allow primary and secondary project IDs, so people who want to
>> >> can refer just to the secondary project ID (boost//)
>> >
>> > Hmm.. I'd rather not compicate projects ID further.
>>
>> I don't think this is really complicated. It's just a project alias. I
>> think it's important if anyone wants to use versioned project IDs
>> because they'll want to use the alias internally to that project anyway
>> for maintenance reasons.
> 
> There's a problem I see with computing build directory from project id 
> specified in "use-project". At the moment, build dir location is a property 
> of a project. So, when --build-dir is specified, we'd need to get all 
> "use-project" directives and modify build directories for the affected 
> projects. Workable, but not nice.

I'm not sure I see that. Why do you think this feature has to change
anything about build directory calculation?

> And what if you have
> 
> use-project boost : /home/ghost/Work/boost ;
> use-project boost-1.32 : /home/ghost/Work/boost ;
> 
> Should this be an error? (Not that this is likely use case, but still we need 
> to consider this)

Not an error. The first use-project assigns a primary project ID to
that directory. The second one assigns a secondary project ID -- just
an alias, like typedef in C++. The primary project ID is used for build
directory calculation.

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com