Re: The right configuration mechanism

From: David Abrahams (dave_at_[hidden])
Date: 2005-08-12 10:02:53

Vladimir Prus <ghost_at_[hidden]> writes:

> On Friday 05 August 2005 23:00, David Abrahams wrote:
>
>> > Wanting to always satisfy as many people as possible I would prefer
>> > to have a way of handling all (a), (b), and (c). And it could be
>> > done if we do (c) out of the box with a more intelligent default
>> > user-config. Having (a) available as "using all : all ;" for all
>> > toolsets and "using msvc : all ;" for individual ones. And having
>> > (b) available as "using all : default ;" and "using msvc :
>> > default;".
>>
>> That's the wrong syntax for this purpose. "using" just configures a
>> toolset; it doesn't say what will be used to build with. I would say:
>>
>> default-toolset msvc-* gcc intel-8.1 ;
>>
>> Build with all versions of msvc, whatever the default (1st configured)
>> gcc version is, and intel-8.1, unless the user puts a toolset name on
>> the command-line.
>
> I think the same can be achieved already by putting the following to 
> user-config.jam:
>
> project : default-build <toolset>msvc-6.0 <toolset>msvc-7.1 ;

Please:

project : default-build toolset=msvc-6.0 toolset=msvc-7.1 ;

IMO that is *way* too obtuse. It's nice and minimal, but What newe
user will think it's natural to treat his configuration file like a
project?

> All projects will be now built with two compilers. OTOH, I have no idea what
> happens if some projects redefines 'default-build'.

It seems as though the _desired_ behavior in that case is obvious.

> We can use 
>
> configure all-c++-compilers : all ;
>
> by creating file called "all-c++-compilers.jam" and implementing it's "init" 
> rule accordingly. It might be bettet to use explicit "all-versions" as 
> argument, though.

I don't see any problem with merely:

configure all-c++-compilers ;

which configures everything. Remember, configuring a toolset doesn't
say *anything* about what will be built.

In fact, maybe we should simply let the user make whatever explicit
configuration he likes, and then run through *all* the toolsets in the
the tools/ directory calling their "auto-configure" rules.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com