<section xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xml:id="sec-language-coq">

<title>Coq</title>
  <para>
    Coq libraries should be installed in
    <literal>$(out)/lib/coq/${coq.coq-version}/user-contrib/</literal>.
    Such directories are automatically added to the
    <literal>$COQPATH</literal> environment variable by the hook defined
    in the Coq derivation.
  </para>
  <para>
    Some libraries require OCaml and sometimes also Camlp5. The exact
    versions that were used to build Coq are saved in the
    <literal>coq.ocaml</literal> and <literal>coq.camlp5</literal>
    attributes.
  </para>
  <para>
    Here is a simple package example. It is a pure Coq library, thus it
    only depends on Coq. Its <literal>makefile</literal> has been
    generated using <literal>coq_makefile</literal> so we only have to
    set the <literal>$COQLIB</literal> variable at install time.
  </para>
  <programlisting>
{stdenv, fetchurl, coq}:
stdenv.mkDerivation {
  src = fetchurl {
    url = http://coq.inria.fr/pylons/contribs/files/Karatsuba/v8.4/Karatsuba.tar.gz;
    sha256 = "0ymfpv4v49k4fm63nq6gcl1hbnnxrvjjp7yzc4973n49b853c5b1";
  };

  name = "coq-karatsuba";

  buildInputs = [ coq ];

  installFlags = "COQLIB=$(out)/lib/coq/${coq.coq-version}/";
}
</programlisting>
</section>

