-*- mode: org; coding: utf-8; -*-

#+TITLE: What's left to do?
#+STARTUP: content hidestars

Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>

  Copying and distribution of this file, with or without modification,
  are permitted in any medium without royalty provided the copyright
  notice and this notice are preserved.

* integrate needed Nix code

** MAYBE Add a substituter that uses the GNUnet DHT or [[http://libswift.org][libswift]]

Would be neat if binaries could be pushed to and pulled from the GNUnet DHT or
rather libswift (since DHTs aren’t suited for large payloads).  Guix users
would sign their binaries, and define which binaries they trust.

Use UPnP and similar to traverse NAT, like ‘filegive’ does.

** Add a remote build hook

Like scripts/build-remote.pl in Nix.

* Add `guix publish' to publish the store using Guile's web server

Generate narinfos and nars on the fly, upon HTTP GET requests.
Ideally, extend .nix-cache-info to include the server's public key, and also
reply to requests for .narinfo.sig.
Optionally, use Guile-Avahi to publish the service.

* user interface
** Add a package.el (Emacs) back-end

package.el is quite monolithic, but we may be able to reuse/extend
‘package-menu-mode’ or at least ‘tabulated-list-mode’.

** add guile-ncurses interface

* extend <package>

** add ‘recommends’ field

For instance, glibc, binutils, gcc, and ld-wrapper would recommend each other.
‘guix package -i’ could ask interactively (?), or allow users to follow all or
none of the recommendations.

** add a ‘user-environment-hook’

This should specify builder code to be run when building a user
environment with ‘guix-package’.  For instance, Texinfo’s hook would
create a new ‘dir’.

** extend ‘propagated-build-inputs’ with support for multiple outputs

#+BEGIN_SRC scheme
  (outputs '("out" "include"))
  (propagated-build-inputs
    `(((("i1" ,p1 "o1")
        ("i2" ,p2))
       => "include")
      ("i3" ,p3)))
#+END_SRC

* MAYBE use HOP-like escapes to refer to inputs in build-side code

Instead of doing things like:

#+BEGIN_SRC scheme
  (inputs `(("foo" ,foo)))
  (arguments '(#:configure-flags
               (list (string-append "--with-foo="
                                    (assoc-ref %build-inputs "foo")))))
#+END_SRC

Allow things like:

#+BEGIN_SRC scheme
  (inputs (list foo))
  (arguments ~(#:configure-flags
               (list (string-append "--with-foo=" $foo))))
  
#+END_SRC

... where '~' is 'build-quote' and '$' is 'build-unquote'.  Better yet,
automatically compute the list of references of an expression passed to
'derivation-expression'.

Use a [[http://dorophone.blogspot.fr/2011/09/scheme-syntax-is-monad.html][monad]] for the syntax.

* synchronize non-GNU package descriptions with the [[http://directory.fsf.org][FSD]]

Meta-data for GNU packages, including descriptions and synopses, can be
dumped from the FSD:
http://directory.fsf.org/wiki?title=GNU/Export&action=purge .
We could periodically synchronize with that.

* add a guildhall build system

The Guildhall is Guile’s packaging system.  It should be easy to add a
‘guildhall-build-system’ that does the right thing based on guildhall
recipes.

* add ‘allowed-references’ in <package>

[[file:~/src/nix/src/libstore/build.cc::if%20(drv.env.find("allowedReferences")%20!%3D%20drv.env.end())%20{][See how Nix implements that internally]].

* union

Support sophisticated collision handling when building a union: check
whether the colliding files are identical, honor per-package priorities,
etc.

* add GUIX_ALLOW_EXPENSIVE_TESTS

Tests that need to download stuff or otherwise take a long time would only be
run when that is defined.

* add "guix challenge"

Would download a substitute, and compare its contents against a (hopefully
locally-built) copy.


* guix build utils
** MAYBE Change ‘ld-wrapper’ to add RPATH for libs passed by file name

** MAYBE Add equivalent to chrpath that uses [[https://gitorious.org/guile-dlhacks/guile-dlhacks/][guile-dlhacks]]

** MAYBE Add a hash-rewriting thing for deep dependency replacement without rebuild

See [[https://github.com/NixOS/nixpkgs/commit/d1662d715514e6ef9d3dc29f132f1b3d8e608a18][Shea Levy's `replace-dependency' in Nixpkgs]].

* distro
** port to new GNU/Linux platforms, notably ‘mipsel64-linux’
** port to GNU/Hurd, aka. ‘i686-gnu’

Problems include that current glibc releases do not build on GNU/Hurd.
In addition, there haven’t been stable releases of GNU Mach, MiG, and
Hurd, which would be a pre-condition.

** make a bootable GNU/Linux-Libre distro, with OS configuration EDSL

Similar in spirit to /etc/nixos/configuration.nix.
