Re: [gentoo-dev] Support for multiple ABIs (for Python modules etc.)

[Ciaran McCreesh]

On Sat, 25 Jul 2009 12:28:44 +0200
Arfrever Frehtes Taifersar Arahesis <Arfrever@g.o> wrote:
> I would like to present the plan of support for multiple ABIs. It
> should be sufficient for Python modules and might be also appropriate
> for some other ABI types (e.g. for Ruby modules).

How do you plan to handle the intersection of ABIs? What if you have to
build or depend upon a Python module for both 32 and 64 bit ABIs, and
for both 2.5 and 2.6? What if you have a package that provides both
Ruby and Python code, where the two ABIs are independent rather than a
product?

> 4.1. Implicitly specified ABI dependencies. During calculation of
> dependencies of given package, Portage will verify if all
> dependencies, which use given ABI type, have been built with enabled
> support for these ABIs, which are enabled for given package.

How do you say "I need only a single ABI for this, even though it looks
like I need every ABI I'm built with"? For example, if your Python
module, being built for 2.5 and 2.6, runs (but does not use in a
library sense) a Python program that comes as part of a Python package
that is buildable with multiple ABIs?

> 4.2. Explicitly specified ABI dependencies. {,P,R}DEPEND variables
> will support specifying ABI dependencies in explicit way.
> {,P,R}DEPEND variables will also support ABI conditionals. I suggest
> using {ABI_type[comma-delimited values]} syntax, but it can be
> changed.

I think we're trying to avoid introducing new special characters if we
can get away with using existing ones. You can overload [] and existing
conditionals if you're careful.

Having said that, you can probably do everything you described slightly
less elegantly just using things that're already in EAPI 3.

-- 
Ciaran McCreesh