Re: [Boost-testing] Toolset Autoconfiguration [was: Martin Wille x86_64 V2 - python]

From: Roland Schwarz (roland.schwarz_at_[hidden])
Date: 2007-03-26 13:05:46

Roland Schwarz wrote:
> So perhaps the autoconfigure should use this function too, and then
> pass only the toolset (i.e. gcc) and version (i.e. 3.4.4) to the using
> rule? At least this is what "using" is expecting to get as input.

Too fast :-( This won't work.

The function relies on the subfeatures already been defined (which
happens inside "using".)

So the notation xxx-yyy-zzz means yyy and zzz being subfeatures of
xxx (whithout a defined order). They are implicitly looked up by
value.

But if this is true, the autoconfig poses a chicken-egg problem,
and none can tell how to parse the xx-yyy-zzz.

Indeed, gcc-mingw-3.4.4 produces
<toolset>gcc/<toolset-gcc:flavor>mingw/<toolset-gcc:version>3.4.4
which also is a correct expansion.

But the autoconfigure never can know which is the "version" part.

I think I begin to understand why Volodya insisted on leaving the
"toolset=" less syntax in place.

Hmm, if we had a rule similar to expand-no-defaults which tries to
deduce the toolset and version, but does not bomb out if a subfeature
cannot be found this could be used to find the correct input to
the using rule.

What do you think?

Roland