nixpkgs/nixos/modules/programs/zsh/oh-my-zsh.xml

<chapter 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="module-programs-zsh-ohmyzsh">

<title>Oh my ZSH</title>

<para><literal><link xlink:href="https://ohmyz.sh/">oh-my-zsh</link></literal> is a framework
to manage your <link xlink:href="https://www.zsh.org/">ZSH</link> configuration
including completion scripts for several CLI tools or custom prompt themes.</para>

<section xml:id="module-programs-oh-my-zsh-usage"><title>Basic usage</title>
<para>The module uses the <literal>oh-my-zsh</literal> package with all available features.  The
initial setup using Nix expressions is fairly similar to the configuration format
of <literal>oh-my-zsh</literal>.

<programlisting>
{
  programs.ohMyZsh = {
    enable = true;
    plugins = [ "git" "python" "man" ];
    theme = "agnoster";
  };
}
</programlisting>

For a detailed explanation of these arguments please refer to the
<link xlink:href="https://github.com/robbyrussell/oh-my-zsh/wiki"><literal>oh-my-zsh</literal> docs</link>.
</para>
<para>The expression generates the needed
configuration and writes it into your <literal>/etc/zshrc</literal>.
</para></section>

<section xml:id="module-programs-oh-my-zsh-additions"><title>Custom additions</title>

<para>Sometimes third-party or custom scripts such as a modified theme may be needed.
<literal>oh-my-zsh</literal> provides the
<link xlink:href="https://github.com/robbyrussell/oh-my-zsh/wiki/Customization#overriding-internals"><literal>ZSH_CUSTOM</literal></link> 
environment variable for this which points to a directory with additional scripts.</para>

<para>The module can do this as well:

<programlisting>
{
  programs.ohMyZsh.custom = "~/path/to/custom/scripts";
}
</programlisting>
</para></section>

<section xml:id="module-programs-oh-my-zsh-environments"><title>Custom environments</title>

<para>There are several extensions for <literal>oh-my-zsh</literal> packaged in <literal>nixpkgs</literal>.
One of them is <link xlink:href="https://github.com/spwhitt/nix-zsh-completions">nix-zsh-completions</link>
which bundles completion scripts and a plugin for <literal>oh-my-zsh</literal>.</para>

<para>Rather than using a single mutable path for <literal>ZSH_CUSTOM</literal>, it's also possible to
generate this path from a list of Nix packages:

<programlisting>
{ pkgs, ... }:
{
  programs.ohMyZsh.customPkgs = with pkgs; [
    pkgs.nix-zsh-completions
    # and even more...
  ];
}
</programlisting>

Internally a single store path will be created using <literal>buildEnv</literal>.
Please refer to the docs of
<link xlink:href="https://nixos.org/nixpkgs/manual/#sec-building-environment"><literal>buildEnv</literal></link>
for further reference.</para>

<para><emphasis>Please keep in mind that this is not compatible with <literal>programs.ohMyZsh.custom</literal>
as it requires an immutable store path while <literal>custom</literal> shall remain mutable! An evaluation failure
will be thrown if both <literal>custom</literal> and <literal>customPkgs</literal> are set.</emphasis>
</para></section>

<section xml:id="module-programs-oh-my-zsh-packaging-customizations"><title>Package your own customizations</title>

<para>If third-party customizations (e.g. new themes) are supposed to be added to <literal>oh-my-zsh</literal>
there are several pitfalls to keep in mind:</para>

<itemizedlist>
  <listitem>
    <para>To comply with the default structure of <literal>ZSH</literal> the entire output needs to be written to
    <literal>$out/share/zsh.</literal></para>
  </listitem>
  <listitem>
    <para>Completion scripts are supposed to be stored at <literal>$out/share/zsh/site-functions</literal>. This directory
    is part of the <literal><link xlink:href="http://zsh.sourceforge.net/Doc/Release/Functions.html">fpath</link></literal>
    and the package should be compatible with pure <literal>ZSH</literal> setups. The module will automatically link
    the contents of <literal>site-functions</literal> to completions directory in the proper store path.</para>
  </listitem>
  <listitem>
    <para>The <literal>plugins</literal> directory needs the structure <literal>pluginname/pluginname.plugin.zsh</literal>
    as structured in the <link xlink:href="https://github.com/robbyrussell/oh-my-zsh/tree/91b771914bc7c43dd7c7a43b586c5de2c225ceb7/plugins">upstream repo.</link>
    </para>
  </listitem>
</itemizedlist>

<para>
A derivation for <literal>oh-my-zsh</literal> may look like this:
<programlisting>
{ stdenv, fetchFromGitHub }:

stdenv.mkDerivation rec {
  name = "exemplary-zsh-customization-${version}";
  version = "1.0.0";
  src = fetchFromGitHub {
    # path to the upstream repository
  };

  dontBuild = true;
  installPhase = ''
    mkdir -p $out/share/zsh/site-functions
    cp {themes,plugins} $out/share/zsh
    cp completions $out/share/zsh/site-functions
  '';
}
</programlisting>
</para>
</section>
</chapter>