Re: [Boost-build] [bbv2] newbie: how to get value of a featureinside a rule

From: Daniel Einspanjer (deinspanjer_at_[hidden])
Date: 2006-02-07 13:58:20

Ohh Ohh! I have been struggling with trying to learn how to do this.
This example allowed me to at least see the value of my <customer> feature.
The next step for me is finding a way to be able to make a <define> based on 
the value of <customer>.
e.g. In my main project, I would like to have the following in my 
requirements section:
<define>CUSTOMER=$(customer)

I can't find a syntax that would allow me to do that.

If someone could spare just a moment to point me at some documentation that 
demonstrates anything like this I would greatly appreciate it.

Just in case, here is the relevant portion of my jamroot:

# Set up our customer variable as a variant that can be specified on the 
command line e.g.
feature customer : internal foo bar : implicit composite propagated 
symmetric ;
feature.set-default customer : internal ;

# customize the internal customer to set this extra define.
feature.compose <customer>internal: <define>_AN_INTERNAL_BUILD ;

import notfile ;
notfile test : @print-customer ;
rule print-customer ( targets * : sources * : properties * )
{
    ECHO "Customer = " [ feature.get-values <customer> : $(properties) ] ;
}

project testproject
    : requirements

#        <define>CUSTOMER=[ feature.get-values <customer> : $(properties) ]

Thanks,

Daniel

"Vladimir Prus" <ghost_at_[hidden]> wrote in message 
news:200602071554.31337.ghost_at_cs.msu.su...
> On Sunday 05 February 2006 14:31, Jaroslav Gresula wrote:
>> Could someone advise me how to retrieve value of a feature within a
>> rule? I followed an example from the docs which uses the toolset.flags
>> rule but with no luck.
>>
>> Below is my attempt, but the TOOLSET variable expands to an empty string.
>>
>> ---
>> local rule this-module-rule ( ) { return [ CALLER_MODULE ] ; }
>> local this-module = [ this-module-rule ] ;
>>
>> import toolset ;
>> toolset.flags $(this-module).print-toolset TOOLSET : <toolset> ;
>>
>> rule print-toolset ( )
>> {
>>    ECHO $(TOOLSET) ;
>> }
>>
>> alias main : : [ print-toolset ] ;
>
> This code is executed during Jamfile parsing stage. It calls the rule
> 'print-toolset', that immediately executes "ECHO", but the value of
> $(TOOLSET) is empty, because it's only set when bjam starts executing
> actions, and only if 'print-toolset' is the updating action for some 
> target.
>
> Try this:
>
>  import notfile ;
>  import toolset ;
>  import feature ;
>
>  notfile test : @print-toolset ;
>
>  rule print-toolset ( targets * : sources * : properties * )
>  {
>      ECHO "Toolset = " [ feature.get-values <toolset> : $(properties) ] ;
>  }
>
> Note that if you run "bjam" with two different toolsets, say:
>
>    bjam gcc intel
>
> you'll see two "Toolset = " lines, one for each time "test" is built.
>
> You might also want to check the newly added FAQ item:
>
>    http://boost.org/boost-build2/doc/html/bbv2/faq.html#id2577795
>
> HTH,
> Volodya
>
>
>
>
>
> _______________________________________________
> Unsubscribe & other changes: 
> http://lists.boost.org/mailman/listinfo.cgi/boost-build
>