Gentoo Archives: gentoo-portage-dev

From: Jeremy Maitin-Shepard <jbms@g.o>
To: gentoo-portage-dev@l.g.o
Subject: Re: [gentoo-portage-dev] Multiple language use, `component-based' design, and other issues
Date: Mon, 12 Jan 2004 15:24:15
In Reply to: Re: [gentoo-portage-dev] Multiple language use, `component-based' design, and other issues by Pieter Van den Abeele
1 Pieter Van den Abeele <pvdabeel@g.o> writes:
3 > [snip: constraints]
5 > So if you want to install kde, qt should be installed with option 'kde'
6 > enabled. But similarily, a component should be able to constrain use flags of
7 > another package. Or a combination of components could be constrained,
8 > ...
10 Ah okay. I did not consider the addition of such constraints. If
11 optional constraints are supported (i.e. pkg1 -> qt(use whatever) OR
12 something-else(not USE=xaw3d)), the problem becomes quite complex; it
13 seems it will be non-deterministic polynomial time with respect to the
14 number of packages in the relevant subset of the dependency graph.
16 > Reasoning about these things is much much easier in something like prolog. But
17 > the real advantage here is that prolog can be regarded as a proof engine and
18 > thus is able to provide a proof why a component with a given specification is in
19 > a configuration. It is important to ensure that the configuration returned is
20 > correct and satisfies user constraints/requirements. So in that sense, it will
21 > be 'provable'. But again, I don't see prolog as an absolute requirement;
22 > everything which provides the equivalent of a Turing Machine should can be used
23 > to implement what I'm doing now in Prolog. The set of features that can be
24 > reused in prolog happens to be bigger than for instance C++ or anything else for
25 > this problem, which speeds up development of an explicatory prototype.
27 I see your point here.
29 --
30 Jeremy Maitin-Shepard
32 --
33 gentoo-portage-dev@g.o mailing list