588 lines
20 KiB
XML
588 lines
20 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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version="5.0"
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xml:id="module-services-emacs">
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<title>Emacs</title>
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<!--
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Documentation contributors:
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Damien Cassou @DamienCassou
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Thomas Tuegel @ttuegel
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Rodney Lorrimar @rvl
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-->
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<para>
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<link xlink:href="http://www.gnu.org/software/emacs/">Emacs</link> is an
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extensible, customizable, self-documenting real-time display editor — and
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more. At its core is an interpreter for Emacs Lisp, a dialect of the Lisp
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programming language with extensions to support text editing.
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</para>
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<para>
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Emacs runs within a graphical desktop environment using the X Window System,
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but works equally well on a text terminal. Under
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<productname>macOS</productname>, a "Mac port" edition is available, which
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uses Apple's native GUI frameworks.
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</para>
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<para>
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<productname>Nixpkgs</productname> provides a superior environment for
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running <application>Emacs</application>. It's simple to create custom builds
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by overriding the default packages. Chaotic collections of Emacs Lisp code
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and extensions can be brought under control using declarative package
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management. <productname>NixOS</productname> even provides a
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<command>systemd</command> user service for automatically starting the Emacs
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daemon.
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</para>
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<section xml:id="module-services-emacs-installing">
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<title>Installing <application>Emacs</application></title>
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<para>
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Emacs can be installed in the normal way for Nix (see
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<xref linkend="sec-package-management" />). In addition, a NixOS
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<emphasis>service</emphasis> can be enabled.
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</para>
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<section xml:id="module-services-emacs-releases">
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<title>The Different Releases of Emacs</title>
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<para>
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<productname>Nixpkgs</productname> defines several basic Emacs packages.
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The following are attributes belonging to the <varname>pkgs</varname> set:
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<variablelist>
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<varlistentry>
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<term>
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<varname>emacs</varname>
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</term>
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<term>
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<varname>emacs25</varname>
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</term>
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<listitem>
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<para>
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The latest stable version of Emacs 25 using the
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<link
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xlink:href="http://www.gtk.org">GTK+ 2</link>
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widget toolkit.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>emacs25-nox</varname>
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</term>
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<listitem>
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<para>
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Emacs 25 built without any dependency on X11 libraries.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>emacsMacport</varname>
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</term>
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<term>
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<varname>emacs25Macport</varname>
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</term>
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<listitem>
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<para>
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Emacs 25 with the "Mac port" patches, providing a more native look and
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feel under macOS.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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<para>
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If those aren't suitable, then the following imitation Emacs editors are
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also available in Nixpkgs:
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<link xlink:href="https://www.gnu.org/software/zile/">Zile</link>,
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<link xlink:href="http://homepage.boetes.org/software/mg/">mg</link>,
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<link xlink:href="http://yi-editor.github.io/">Yi</link>.
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</para>
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</section>
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<section xml:id="module-services-emacs-adding-packages">
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<title>Adding Packages to Emacs</title>
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<para>
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Emacs includes an entire ecosystem of functionality beyond text editing,
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including a project planner, mail and news reader, debugger interface,
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calendar, and more.
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</para>
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<para>
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Most extensions are gotten with the Emacs packaging system
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(<filename>package.el</filename>) from
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<link
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xlink:href="https://elpa.gnu.org/">Emacs Lisp Package Archive
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(<acronym>ELPA</acronym>)</link>,
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<link xlink:href="https://melpa.org/"><acronym>MELPA</acronym></link>,
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<link xlink:href="https://stable.melpa.org/">MELPA Stable</link>, and
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<link xlink:href="http://orgmode.org/elpa.html">Org ELPA</link>. Nixpkgs is
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regularly updated to mirror all these archives.
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</para>
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<para>
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Under NixOS, you can continue to use
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<function>package-list-packages</function> and
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<function>package-install</function> to install packages. You can also
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declare the set of Emacs packages you need using the derivations from
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Nixpkgs. The rest of this section discusses declarative installation of
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Emacs packages through nixpkgs.
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</para>
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<note>
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<para>
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This documentation describes the new Emacs packages framework in NixOS
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16.03 (<varname>emacsPackagesNg</varname>) which should not be confused
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with the previous and deprecated framework
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(<varname>emacs24Packages</varname>).
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</para>
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</note>
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<para>
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The first step to declare the list of packages you want in your Emacs
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installation is to create a dedicated derivation. This can be done in a
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dedicated <filename>emacs.nix</filename> file such as:
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<example xml:id="ex-emacsNix">
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<title>Nix expression to build Emacs with packages (<filename>emacs.nix</filename>)</title>
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<programlisting language="nix">
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/*
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This is a nix expression to build Emacs and some Emacs packages I like
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from source on any distribution where Nix is installed. This will install
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all the dependencies from the nixpkgs repository and build the binary files
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without interfering with the host distribution.
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To build the project, type the following from the current directory:
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$ nix-build emacs.nix
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To run the newly compiled executable:
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$ ./result/bin/emacs
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*/
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{ pkgs ? import <nixpkgs> {} }: <co xml:id="ex-emacsNix-1" />
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let
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myEmacs = pkgs.emacs; <co xml:id="ex-emacsNix-2" />
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emacsWithPackages = (pkgs.emacsPackagesNgGen myEmacs).emacsWithPackages; <co xml:id="ex-emacsNix-3" />
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in
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emacsWithPackages (epkgs: (with epkgs.melpaStablePackages; [ <co xml:id="ex-emacsNix-4" />
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magit # ; Integrate git <C-x g>
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zerodark-theme # ; Nicolas' theme
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]) ++ (with epkgs.melpaPackages; [ <co xml:id="ex-emacsNix-5" />
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undo-tree # ; <C-x u> to show the undo tree
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zoom-frm # ; increase/decrease font size for all buffers %lt;C-x C-+>
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]) ++ (with epkgs.elpaPackages; [ <co xml:id="ex-emacsNix-6" />
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auctex # ; LaTeX mode
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beacon # ; highlight my cursor when scrolling
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nameless # ; hide current package name everywhere in elisp code
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]) ++ [
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pkgs.notmuch # From main packages set <co xml:id="ex-emacsNix-7" />
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])
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</programlisting>
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</example>
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<calloutlist>
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<callout arearefs="ex-emacsNix-1">
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<para>
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The first non-comment line in this file (<literal>{ pkgs ? ...
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}</literal>) indicates that the whole file represents a function.
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</para>
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</callout>
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<callout arearefs="ex-emacsNix-2">
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<para>
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The <varname>let</varname> expression below defines a
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<varname>myEmacs</varname> binding pointing to the current stable
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version of Emacs. This binding is here to separate the choice of the
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Emacs binary from the specification of the required packages.
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</para>
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</callout>
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<callout arearefs="ex-emacsNix-3">
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<para>
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This generates an <varname>emacsWithPackages</varname> function. It
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takes a single argument: a function from a package set to a list of
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packages (the packages that will be available in Emacs).
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</para>
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</callout>
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<callout arearefs="ex-emacsNix-4">
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<para>
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The rest of the file specifies the list of packages to install. In the
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example, two packages (<varname>magit</varname> and
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<varname>zerodark-theme</varname>) are taken from MELPA stable.
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</para>
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</callout>
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<callout arearefs="ex-emacsNix-5">
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<para>
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Two packages (<varname>undo-tree</varname> and
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<varname>zoom-frm</varname>) are taken from MELPA.
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</para>
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</callout>
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<callout arearefs="ex-emacsNix-6">
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<para>
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Three packages are taken from GNU ELPA.
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</para>
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</callout>
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<callout arearefs="ex-emacsNix-7">
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<para>
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<varname>notmuch</varname> is taken from a nixpkgs derivation which
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contains an Emacs mode.
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</para>
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</callout>
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</calloutlist>
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</para>
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<para>
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The result of this configuration will be an <command>emacs</command>
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command which launches Emacs with all of your chosen packages in the
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<varname>load-path</varname>.
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</para>
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<para>
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You can check that it works by executing this in a terminal:
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<screen>
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$ nix-build emacs.nix
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$ ./result/bin/emacs -q
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</screen>
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and then typing <literal>M-x package-initialize</literal>. Check that you
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can use all the packages you want in this Emacs instance. For example, try
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switching to the zerodark theme through <literal>M-x load-theme <RET>
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zerodark <RET> y</literal>.
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</para>
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<tip>
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<para>
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A few popular extensions worth checking out are: auctex, company,
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edit-server, flycheck, helm, iedit, magit, multiple-cursors, projectile,
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and yasnippet.
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</para>
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</tip>
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<para>
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The list of available packages in the various ELPA repositories can be seen
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with the following commands:
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<example xml:id="module-services-emacs-querying-packages">
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<title>Querying Emacs packages</title>
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<programlisting><![CDATA[
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nix-env -f "<nixpkgs>" -qaP -A emacsPackagesNg.elpaPackages
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nix-env -f "<nixpkgs>" -qaP -A emacsPackagesNg.melpaPackages
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nix-env -f "<nixpkgs>" -qaP -A emacsPackagesNg.melpaStablePackages
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nix-env -f "<nixpkgs>" -qaP -A emacsPackagesNg.orgPackages
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]]></programlisting>
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</example>
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</para>
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<para>
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If you are on NixOS, you can install this particular Emacs for all users by
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adding it to the list of system packages (see
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<xref linkend="sec-declarative-package-mgmt" />). Simply modify your file
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<filename>configuration.nix</filename> to make it contain:
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<example xml:id="module-services-emacs-configuration-nix">
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<title>Custom Emacs in <filename>configuration.nix</filename></title>
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<programlisting><![CDATA[
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{
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environment.systemPackages = [
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# [...]
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(import /path/to/emacs.nix { inherit pkgs; })
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];
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}
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]]></programlisting>
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</example>
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</para>
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<para>
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In this case, the next <command>nixos-rebuild switch</command> will take
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care of adding your <command>emacs</command> to the <varname>PATH</varname>
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environment variable (see <xref linkend="sec-changing-config" />).
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</para>
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<!-- fixme: i think the following is better done with config.nix
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https://nixos.org/nixpkgs/manual/#sec-modify-via-packageOverrides
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-->
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<para>
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If you are not on NixOS or want to install this particular Emacs only for
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yourself, you can do so by adding it to your
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<filename>~/.config/nixpkgs/config.nix</filename> (see
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<link xlink:href="http://nixos.org/nixpkgs/manual/#sec-modify-via-packageOverrides">Nixpkgs
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manual</link>):
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<example xml:id="module-services-emacs-config-nix">
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<title>Custom Emacs in <filename>~/.config/nixpkgs/config.nix</filename></title>
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<programlisting><![CDATA[
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{
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packageOverrides = super: let self = super.pkgs; in {
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myemacs = import /path/to/emacs.nix { pkgs = self; };
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};
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}
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]]></programlisting>
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</example>
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</para>
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<para>
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In this case, the next <literal>nix-env -f '<nixpkgs>' -iA
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myemacs</literal> will take care of adding your emacs to the
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<varname>PATH</varname> environment variable.
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</para>
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</section>
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<section xml:id="module-services-emacs-advanced">
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<title>Advanced Emacs Configuration</title>
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<para>
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If you want, you can tweak the Emacs package itself from your
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<filename>emacs.nix</filename>. For example, if you want to have a
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GTK+3-based Emacs instead of the default GTK+2-based binary and remove the
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automatically generated <filename>emacs.desktop</filename> (useful is you
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only use <command>emacsclient</command>), you can change your file
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<filename>emacs.nix</filename> in this way:
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</para>
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<example xml:id="ex-emacsGtk3Nix">
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<title>Custom Emacs build</title>
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<programlisting><![CDATA[
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{ pkgs ? import <nixpkgs> {} }:
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let
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myEmacs = (pkgs.emacs.override {
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# Use gtk3 instead of the default gtk2
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withGTK3 = true;
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withGTK2 = false;
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}).overrideAttrs (attrs: {
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# I don't want emacs.desktop file because I only use
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# emacsclient.
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postInstall = (attrs.postInstall or "") + ''
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rm $out/share/applications/emacs.desktop
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'';
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});
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in [...]
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]]></programlisting>
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</example>
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<para>
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After building this file as shown in <xref linkend="ex-emacsNix" />, you
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will get an GTK3-based Emacs binary pre-loaded with your favorite packages.
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</para>
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</section>
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</section>
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<section xml:id="module-services-emacs-running">
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<title>Running Emacs as a Service</title>
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<para>
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<productname>NixOS</productname> provides an optional
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<command>systemd</command> service which launches
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<link xlink:href="https://www.gnu.org/software/emacs/manual/html_node/emacs/Emacs-Server.html">
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Emacs daemon </link> with the user's login session.
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</para>
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<para>
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<emphasis>Source:</emphasis>
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<filename>modules/services/editors/emacs.nix</filename>
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</para>
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<section xml:id="module-services-emacs-enabling">
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<title>Enabling the Service</title>
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<para>
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To install and enable the <command>systemd</command> user service for Emacs
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daemon, add the following to your <filename>configuration.nix</filename>:
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<programlisting>
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<xref linkend="opt-services.emacs.enable"/> = true;
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<xref linkend="opt-services.emacs.package"/> = import /home/cassou/.emacs.d { pkgs = pkgs; };
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</programlisting>
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</para>
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<para>
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The <varname>services.emacs.package</varname> option allows a custom
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derivation to be used, for example, one created by
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<function>emacsWithPackages</function>.
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</para>
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<para>
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Ensure that the Emacs server is enabled for your user's Emacs
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configuration, either by customizing the <varname>server-mode</varname>
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variable, or by adding <literal>(server-start)</literal> to
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<filename>~/.emacs.d/init.el</filename>.
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</para>
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<para>
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To start the daemon, execute the following:
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<screen>
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$ nixos-rebuild switch # to activate the new configuration.nix
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$ systemctl --user daemon-reload # to force systemd reload
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$ systemctl --user start emacs.service # to start the Emacs daemon
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</screen>
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The server should now be ready to serve Emacs clients.
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</para>
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</section>
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<section xml:id="module-services-emacs-starting-client">
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<title>Starting the client</title>
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<para>
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Ensure that the emacs server is enabled, either by customizing the
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<varname>server-mode</varname> variable, or by adding
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<literal>(server-start)</literal> to <filename>~/.emacs</filename>.
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</para>
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<para>
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To connect to the emacs daemon, run one of the following:
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<programlisting><![CDATA[
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emacsclient FILENAME
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emacsclient --create-frame # opens a new frame (window)
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emacsclient --create-frame --tty # opens a new frame on the current terminal
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]]></programlisting>
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</para>
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</section>
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<section xml:id="module-services-emacs-editor-variable">
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<title>Configuring the <varname>EDITOR</varname> variable</title>
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<!--<title><command>emacsclient</command> as the Default Editor</title>-->
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<para>
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If <xref linkend="opt-services.emacs.defaultEditor"/> is
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<literal>true</literal>, the <varname>EDITOR</varname> variable will be set
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to a wrapper script which launches <command>emacsclient</command>.
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</para>
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<para>
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Any setting of <varname>EDITOR</varname> in the shell config files will
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override <varname>services.emacs.defaultEditor</varname>. To make sure
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<varname>EDITOR</varname> refers to the Emacs wrapper script, remove any
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existing <varname>EDITOR</varname> assignment from
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<filename>.profile</filename>, <filename>.bashrc</filename>,
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<filename>.zshenv</filename> or any other shell config file.
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</para>
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<para>
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If you have formed certain bad habits when editing files, these can be
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corrected with a shell alias to the wrapper script:
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<programlisting>alias vi=$EDITOR</programlisting>
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</para>
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</section>
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<section xml:id="module-services-emacs-per-user">
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<title>Per-User Enabling of the Service</title>
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<para>
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In general, <command>systemd</command> user services are globally enabled
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by symlinks in <filename>/etc/systemd/user</filename>. In the case where
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Emacs daemon is not wanted for all users, it is possible to install the
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service but not globally enable it:
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<programlisting>
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<xref linkend="opt-services.emacs.enable"/> = false;
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<xref linkend="opt-services.emacs.install"/> = true;
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</programlisting>
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</para>
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<para>
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To enable the <command>systemd</command> user service for just the
|
|
currently logged in user, run:
|
|
<programlisting>systemctl --user enable emacs</programlisting>
|
|
This will add the symlink
|
|
<filename>~/.config/systemd/user/emacs.service</filename>.
|
|
</para>
|
|
</section>
|
|
</section>
|
|
<section xml:id="module-services-emacs-configuring">
|
|
<title>Configuring Emacs</title>
|
|
|
|
<para>
|
|
The Emacs init file should be changed to load the extension packages at
|
|
startup:
|
|
<example xml:id="module-services-emacs-package-initialisation">
|
|
<title>Package initialization in <filename>.emacs</filename></title>
|
|
<programlisting><![CDATA[
|
|
(require 'package)
|
|
|
|
;; optional. makes unpure packages archives unavailable
|
|
(setq package-archives nil)
|
|
|
|
(setq package-enable-at-startup nil)
|
|
(package-initialize)
|
|
]]></programlisting>
|
|
</example>
|
|
</para>
|
|
|
|
<para>
|
|
After the declarative emacs package configuration has been tested,
|
|
previously downloaded packages can be cleaned up by removing
|
|
<filename>~/.emacs.d/elpa</filename> (do make a backup first, in case you
|
|
forgot a package).
|
|
</para>
|
|
|
|
<!--
|
|
todo: is it worth documenting customizations for
|
|
server-switch-hook, server-done-hook?
|
|
-->
|
|
|
|
<section xml:id="module-services-emacs-major-mode">
|
|
<title>A Major Mode for Nix Expressions</title>
|
|
|
|
<para>
|
|
Of interest may be <varname>melpaPackages.nix-mode</varname>, which
|
|
provides syntax highlighting for the Nix language. This is particularly
|
|
convenient if you regularly edit Nix files.
|
|
</para>
|
|
</section>
|
|
|
|
<section xml:id="module-services-emacs-man-pages">
|
|
<title>Accessing man pages</title>
|
|
|
|
<para>
|
|
You can use <function>woman</function> to get completion of all available
|
|
man pages. For example, type <literal>M-x woman <RET> nixos-rebuild
|
|
<RET>.</literal>
|
|
</para>
|
|
</section>
|
|
|
|
<section xml:id="sec-emacs-docbook-xml">
|
|
<title>Editing DocBook 5 XML Documents</title>
|
|
|
|
<para>
|
|
Emacs includes
|
|
<link
|
|
xlink:href="https://www.gnu.org/software/emacs/manual/html_node/nxml-mode/Introduction.html">nXML</link>,
|
|
a major-mode for validating and editing XML documents. When editing DocBook
|
|
5.0 documents, such as <link linkend="book-nixos-manual">this one</link>,
|
|
nXML needs to be configured with the relevant schema, which is not
|
|
included.
|
|
</para>
|
|
|
|
<para>
|
|
To install the DocBook 5.0 schemas, either add
|
|
<varname>pkgs.docbook5</varname> to
|
|
<xref linkend="opt-environment.systemPackages"/>
|
|
(<link
|
|
linkend="sec-declarative-package-mgmt">NixOS</link>), or run
|
|
<literal>nix-env -i pkgs.docbook5</literal>
|
|
(<link linkend="sec-ad-hoc-packages">Nix</link>).
|
|
</para>
|
|
|
|
<para>
|
|
Then customize the variable <varname>rng-schema-locating-files</varname> to
|
|
include <filename>~/.emacs.d/schemas.xml</filename> and put the following
|
|
text into that file:
|
|
<example xml:id="ex-emacs-docbook-xml">
|
|
<title>nXML Schema Configuration (<filename>~/.emacs.d/schemas.xml</filename>)</title>
|
|
<programlisting language="xml"><![CDATA[
|
|
<?xml version="1.0"?>
|
|
<!--
|
|
To let emacs find this file, evaluate:
|
|
(add-to-list 'rng-schema-locating-files "~/.emacs.d/schemas.xml")
|
|
-->
|
|
<locatingRules xmlns="http://thaiopensource.com/ns/locating-rules/1.0">
|
|
<!--
|
|
Use this variation if pkgs.docbook5 is added to environment.systemPackages
|
|
-->
|
|
<namespace ns="http://docbook.org/ns/docbook"
|
|
uri="/run/current-system/sw/share/xml/docbook-5.0/rng/docbookxi.rnc"/>
|
|
<!--
|
|
Use this variation if installing schema with "nix-env -iA pkgs.docbook5".
|
|
<namespace ns="http://docbook.org/ns/docbook"
|
|
uri="../.nix-profile/share/xml/docbook-5.0/rng/docbookxi.rnc"/>
|
|
-->
|
|
</locatingRules>
|
|
]]></programlisting>
|
|
</example>
|
|
</para>
|
|
</section>
|
|
</section>
|
|
</chapter>
|