Re: [Boost-build] Python/Cygwin support in v2

From: Vladimir Prus (ghost_at_[hidden])
Date: 2006-12-23 13:41:41

On Monday 11 December 2006 02:34, David Abrahams wrote:
> 
> 1. cygwin-condition: there's a comment now, but it's still quite
>    unclear.  How should this argument be used?  We need an example.
> 
>    I'm beginning to think it should look something like:
> 
>          <toolset>gcc
> 
>    The comment says, "should be a set of properties which are present
>    when we're building with cygwin gcc," but (if my theory above is
>    correct) that fails to indicate the primary distinguishing feature
>    of the argument, which is that it must identify the cygwin-gcc
>    toolset.

Ideally, the purpose of this argument is to be able to configure several versions
of python, and use a specific version only when specific properties are in build properties.
 
> 2. Also the comment says: "This argument is not used yet," but it
>    clearly /is/ used.  Code branches are followed based on its
>    value.

That comment is not longer occurate.

> 3. The logic in this file that is used when the cygwin branch is
>    followed seems to have been copy/pasted from the v1 python support,
>    with all kinds of ends left dangling.  For example, what do all the
>    CYGWIN_PYTHON_DEBUG_* variable settings do?  Nothing AFAICT.

Yeah, looks like cygwin support was never ported, because I don't have
cygwin to test anything. I think there are two possible issues:

1. We want to be able to configure several versions of python -- cygwin python,
msvc python, maybe mingw python. If that's needed, then declarations of all targets
in init-nt should include condition. Also:

        flags python.capture-output PYTHON : $(interpreter) ;

should become:

        flags python.capture-output PYTHON $(condition:J=/) : $(interpreter) ;

2. If we need cygwin-specific configuration logic we need to know when
cygwin python is initialized. Perhaps new value of 'flavour' feature -- 'cygwin',
can be used. So, for

        python 2.3 : /whatever : : : <toolset:gcc-flavour>cygwin ;

we'll know that cygwin python is initialized and adjust configuration code.

Does this help?

- Volodya

- Volodya