Re: Free feature problem

From: David Abrahams (dave_at_[hidden])
Date: 2004-07-02 10:14:06

Vladimir Prus <ghost_at_[hidden]> writes:

> David Abrahams wrote:
>
>> > Folks, how do you feel about some rule like:
>> >
>> > use-property ( property )
>> >
>> > which would be used like:
>> >
>> > use-property <os>NT ;
>> >
>> > and will make NT a valid value of the <os> feature. If <os>NT is defined
>> > already, the above will be no-op?
>> >
>> > This is something we planned for some time... maybe we should add it now?
>> >
>> > Thoughts?
>>
>> Seems as though it ought to be unneccessary, doesn't it?
>
> Why? The problem is: you want to use <toolset>msvc in requirements. 

But only as a condition, right? If it were an actual requirement,
also asking people to have "using msvc" would be no problem.

> You don't want to "using msvc " because that would warn that msvc is
> not installed. So you need a way to say the <toolset>msvc is OK.

Why shouldn't the person who defines the <toolset> feature do that
once instead of requiring everyone who wants to use it in a condition
to do a use-property?

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