From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Craven Subject: Re: gexps Date: Thu, 1 Sep 2016 13:58:31 +0200 Message-ID: References: <87zinrrgt2.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:37330) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bfQdh-0002Vj-No for guix-devel@gnu.org; Thu, 01 Sep 2016 07:58:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bfQde-00004q-Ka for guix-devel@gnu.org; Thu, 01 Sep 2016 07:58:37 -0400 Received: from mail-yw0-x235.google.com ([2607:f8b0:4002:c05::235]:34846) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bfQdd-0008WC-D5 for guix-devel@gnu.org; Thu, 01 Sep 2016 07:58:34 -0400 Received: by mail-yw0-x235.google.com with SMTP id j12so48657193ywb.2 for ; Thu, 01 Sep 2016 04:58:32 -0700 (PDT) In-Reply-To: <87zinrrgt2.fsf@gnu.org> List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: "Guix-devel" To: =?UTF-8?Q?Ludovic_Court=C3=A8s?= Cc: guix-devel > If we force use of the host system type (say x86_64-linux), independent > of (%current-system) (say mips64el-linux), we approach what you want. > However, that would give us different derivations depending on the host > system type. That is, =E2=80=98guix system build -s mips64el-linux -d=E2= =80=99 on > x86_64 would return something different from =E2=80=98guix system build -= d=E2=80=99 on > mips64. This is not desirable. Maybe an option would be if %current-system !=3D host-system run guile using qemu-arm? > An option would to have =E2=80=98gexp->file=E2=80=99 produce a fixed-outp= ut derivation > (it can compute the hash of the output on the host side). > > Or maybe we need another mechanism similar to fixed-output derivations > to define equivalence classes of derivations. I'll have to read up on fixed-output derivations. Can you give me an example of where they are used currently?