In python, the version number is higher up in the directory hierarchy,
which, hypothetically, allows newer versions to have "inventions" in the
more detailed directory structure:

/usr/lib/python2.6
/usr/lib/python2.7
etc

Just a thought.

On Fri, Mar 4, 2016 at 2:13 PM, Jan Nieuwenhuizen <janneke@gnu.org> wrote:

> Hi,
>
> I am running guile-2.0 and guile-2.2 alongside each other which is
> causing me some pain*).
>
> This is what bits of my GUILE_LOAD_COMPILED_PATH look like
>
>
> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/lib/guile/2.2/ccache
>     -->
> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/lib/guile/2.2/ccache/ice-9/and-let-star.go
>
>
> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site/2.2/
>     -->
> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site/2.2/os/process.go
>
> If `/<effective-version>' is always used as the suffix of each path
> element, and we/guix/packagers do not include that suffix in GUILE_*PATH
> elements, then Guile can append effective-prefix and different major
> Guile-versions can happily share the same GUILE_LOAD[_COMPILED]_PATH,
> e.g., having
>
>
> GUILE_LOAD_COMPILED_PATH=/gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site
>
> then guile-2.0 would get (os process) from
>
>     /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site +
> /2.0
>     -->
> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site/2.0/os/process.go
>
> and guile-2.2 would read
>
>     /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site +
> /2.2
>     -->
> /gnu/store/7ml4psifv46pzxjxw56xfl7mwd47k277-profile/share/guile/site/2.2/os/process.go
>
> What do you think?  No more pain!  Find patch attached.
>
> Greetings,
> Jan
>
>
> *) Some of my pain
>
> My Debian host system has guile-2.0, guix depends on guile-2.0, guix's
> LD script depends on guile-2.0, the guile bits of my project depend on
> guile-2.2.
>
> I have some scripts to make this situation almost bearable, but still I
> regularly
>
> cannot find a basic library
>
>     [1]13:53:25 janneke@janneke-ijzer:~
>     $ guile --no-auto-compile
>     GNU Guile 2.0.11
>     Copyright (C) 1995-2014 Free Software Foundation, Inc.
>
>     Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
>     This program is free software, and you are welcome to redistribute it
>     under certain conditions; type `,show c' for details.
>
>     Enter `,help' for help.
>     scheme@(guile-user)> (use-modules (os proccess))
>     While compiling expression:
>     ERROR: no code for module (os proccess)
>
> or some guile script (guix) aborts
>
>     guix environment --ad-hoc ccache coreutils git guix emacs guile-next
> guile-next-lib
>     Throw without catch before boot:
>     Throw to key misc-error with args ("make_objcode_from_file" "bad
> header on object file: ~s"
> ("\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00") #f)Aborting.
>     Aborted
>
> or linking breaks
>
>     g++ -Wall -std=c++11  -g -I. -I out/alarm.project/c++ -I
> check/alarm.project/   out/alarm.project/c++/main.o
> out/alarm.project/c++/Alarm.o out/alarm.project/c++/AlarmSystem.o
> out/alarm.project/c++/pump.o out/alarm.project/c++/runtime.o
> -lboost_system -lboost_coroutine -lboost_thread -lboost_context -pthread -o
> out/alarm.project/c++/test
>     collect2: error: ld terminated with signal 6 [Afgebroken]
>     Throw without catch before boot:
>     Aborting.
>
> and then I juggle installed guile versions and/or manually modify
> GUILE_LOAD_COMPILED_PATH.
>
>
>
> --
> Jan Nieuwenhuizen <janneke@gnu.org> | GNU LilyPond http://lilypond.org
> Freelance IT http://JoyofSource.com | Avatar®  http://AvatarAcademy.nl
>
>