Re: [jamboost] feature.jam: Need help with subfeatures

From: Vladimir Prus (ghost_at_[hidden])
Date: 2002-11-27 06:14:10

Vladimir Prus wrote:

> The comment for 'value-string' parameter of 'subfeature' rule
> is much more clear for me.

Sorry, it's no longer clear to me. I thought that subfeatures
form a tree. I.e. you can declared one subfeature, and that another
one under it, etc. But this is not so.

Looking at the definitions in the user manual, I'd like to ask for
clarifications:

1. In definition of subfeature -- can parent feature be subfeature itself?

2. In definition of 'value-string' --- what are "related subfeatures".

Going back: what presicely mean 'value-string' parameter to 'subfeature'
and 'extend-subfeature. Lastly, consider this:

feature.extend toolset : gcc ;
feature.subfeature toolset gcc : version : : optional ;
feature.extend-subfeature toolset gcc : version : 3.2 ;

The last line does not change the set of allowed values of
<toolset-version>, because I get this

bjam toolset=gcc toolset-version=3.2
/home/ghost/Work/boost/tools/build/examples-v2/../new/property.jam:221: in 
property.validate from module property
error: Invalid property '<toolset-version>3.2': value '3.2' is not valid for 
feature'toolset-version'.
/home/ghost/Work/boost/tools/build/examples-v2/../new/build-request.jam:182: 
in convert-command-line-element from module build-request

Is this the right behaviour?

- Volodya