lix/doc/manual/bugs.xml

<appendix>
  <title>Bugs / To-Do</title>

  <itemizedlist>

    <listitem>
      <para>
        Unify the concepts of successors and substitutes into a
        general notion of <emphasis>equivalent expressions</emphasis>.
        Expressions are equivalent if they have the same target paths
        with the same identifiers.  However, even though they are
        functionally equivalent, they may differ stronly with respect
        to their <emphasis>performance characteristics</emphasis>.
        For example, realising a closure expression is more efficient
        that realising the derivation expression from which it was
        produced.  On the other hand, distributing sources may be more
        efficient (storage- or bandwidth-wise) than distributing
        binaries.  So we need to be able to attach weigths or
        priorities or performance annotations to expressions; Nix can
        then choose the most efficient expression dependent on the
        context.
      </para>
    </listitem>

    <listitem>
      <para>
        <emphasis>Build management.</emphasis>  In principle it is already
        possible to do build management using Nix (by writing builders that
        perform appropriate build steps), but the Nix expression language is
        not yet powerful enough to make this pleasant (?).  The language should
        be extended with features from the <ulink
          url='http://www.cs.uu.nl/~eelco/maak/'>Maak build manager</ulink>.
        Another interesting idea is to write a <command>make</command>
        implementation that uses Nix as a back-end to support <ulink
          url='http://www.research.att.com/~bs/bs_faq.html#legacy'>legacy</ulink> 
        build files.
      </para>
    </listitem>

  </itemizedlist>

</appendix>

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