<section xmlns="http://docbook.org/ns/docbook"
      xmlns:xlink="http://www.w3.org/1999/xlink"
      xmlns:xi="http://www.w3.org/2001/XInclude"
      version="5.0"
      xml:id="ch-relnotes-0.6">

<title>Release 0.6 (2004-11-14)</title>

<itemizedlist>

  <listitem>
    <para>Rewrite of the normalisation engine.

    <itemizedlist>

      <listitem><para>Multiple builds can now be performed in parallel
      (option <option>-j</option>).</para></listitem>

      <listitem><para>Distributed builds.  Nix can now call a shell
      script to forward builds to Nix installations on remote
      machines, which may or may not be of the same platform
      type.</para></listitem>

      <listitem><para>Option <option>--fallback</option> allows
      recovery from broken substitutes.</para></listitem>

      <listitem><para>Option <option>--keep-going</option> causes
      building of other (unaffected) derivations to continue if one
      failed.</para></listitem>

    </itemizedlist>

    </para>

  </listitem>

  <listitem><para>Improvements to the garbage collector (i.e., it
  should actually work now).</para></listitem>

  <listitem><para>Setuid Nix installations allow a Nix store to be
  shared among multiple users.</para></listitem>

  <listitem><para>Substitute registration is much faster
  now.</para></listitem>

  <listitem><para>A utility <command>nix-build</command> to build a
  Nix expression and create a symlink to the result int the current
  directory; useful for testing Nix derivations.</para></listitem>

  <listitem><para>Manual updates.</para></listitem>

  <listitem>

    <para><command>nix-env</command> changes:

    <itemizedlist>

      <listitem><para>Derivations for other platforms are filtered out
      (which can be overridden using
      <option>--system-filter</option>).</para></listitem>

      <listitem><para><option>--install</option> by default now
      uninstall previous derivations with the same
      name.</para></listitem>

      <listitem><para><option>--upgrade</option> allows upgrading to a
      specific version.</para></listitem>

      <listitem><para>New operation
      <option>--delete-generations</option> to remove profile
      generations (necessary for effective garbage
      collection).</para></listitem>

      <listitem><para>Nicer output (sorted,
      columnised).</para></listitem>

    </itemizedlist>

    </para>

  </listitem>

  <listitem><para>More sensible verbosity levels all around (builder
  output is now shown always, unless <option>-Q</option> is
  given).</para></listitem>

  <listitem>

    <para>Nix expression language changes:

    <itemizedlist>

      <listitem><para>New language construct: <literal>with
      <replaceable>E1</replaceable>;
      <replaceable>E2</replaceable></literal> brings all attributes
      defined in the attribute set <replaceable>E1</replaceable> in
      scope in <replaceable>E2</replaceable>.</para></listitem>

      <listitem><para>Added a <function>map</function>
      function.</para></listitem>

      <listitem><para>Various new operators (e.g., string
      concatenation).</para></listitem>

    </itemizedlist>

    </para>

  </listitem>

  <listitem><para>Expression evaluation is much
  faster.</para></listitem>

  <listitem><para>An Emacs mode for editing Nix expressions (with
  syntax highlighting and indentation) has been
  added.</para></listitem>

  <listitem><para>Many bug fixes.</para></listitem>

</itemizedlist>

</section>
