Chunk NixOS manual

[Squashed commits to make git blame etc. more likely to work. -ED]

nixos/doc/manual/configuration/config-syntax.xml

@@ -0,0 +1,27 @@
+<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="sec-configuration-syntax">
+
+<title>Configuration Syntax</title>
+
+<para>The NixOS configuration file
+<filename>/etc/nixos/configuration.nix</filename> is actually a
+<emphasis>Nix expression</emphasis>, which is the Nix package
+manager’s purely functional language for describing how to build
+packages and configurations.  This means you have all the expressive
+power of that language at your disposal, including the ability to
+abstract over common patterns, which is very useful when managing
+complex systems.  The syntax and semantics of the Nix language are
+fully described in the <link
+xlink:href="http://nixos.org/nix/manual/#chap-writing-nix-expressions">Nix
+manual</link>, but here we give a short overview of the most important
+constructs useful in NixOS configuration files.</para>
+
+<xi:include href="config-file.xml" />
+<xi:include href="abstractions.xml" />
+<xi:include href="modularity.xml" />
+<xi:include href="summary.xml" />
+
+</chapter>