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diff --git a/third_party/nix/doc/manual/glossary/glossary.xml b/third_party/nix/doc/manual/glossary/glossary.xml new file mode 100644 index 0000000000..e3162ed8d4 --- /dev/null +++ b/third_party/nix/doc/manual/glossary/glossary.xml @@ -0,0 +1,199 @@ +<appendix xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xml:id="part-glossary"> + +<title>Glossary</title> + + +<glosslist> + + +<glossentry xml:id="gloss-derivation"><glossterm>derivation</glossterm> + + <glossdef><para>A description of a build action. The result of a + derivation is a store object. Derivations are typically specified + in Nix expressions using the <link + linkend="ssec-derivation"><function>derivation</function> + primitive</link>. These are translated into low-level + <emphasis>store derivations</emphasis> (implicitly by + <command>nix-env</command> and <command>nix-build</command>, or + explicitly by <command>nix-instantiate</command>).</para></glossdef> + +</glossentry> + + +<glossentry><glossterm>store</glossterm> + + <glossdef><para>The location in the file system where store objects + live. Typically <filename>/nix/store</filename>.</para></glossdef> + +</glossentry> + + +<glossentry><glossterm>store path</glossterm> + + <glossdef><para>The location in the file system of a store object, + i.e., an immediate child of the Nix store + directory.</para></glossdef> + +</glossentry> + + +<glossentry><glossterm>store object</glossterm> + + <glossdef><para>A file that is an immediate child of the Nix store + directory. These can be regular files, but also entire directory + trees. Store objects can be sources (objects copied from outside of + the store), derivation outputs (objects produced by running a build + action), or derivations (files describing a build + action).</para></glossdef> + +</glossentry> + + +<glossentry xml:id="gloss-substitute"><glossterm>substitute</glossterm> + + <glossdef><para>A substitute is a command invocation stored in the + Nix database that describes how to build a store object, bypassing + the normal build mechanism (i.e., derivations). Typically, the + substitute builds the store object by downloading a pre-built + version of the store object from some server.</para></glossdef> + +</glossentry> + + +<glossentry><glossterm>purity</glossterm> + + <glossdef><para>The assumption that equal Nix derivations when run + always produce the same output. This cannot be guaranteed in + general (e.g., a builder can rely on external inputs such as the + network or the system time) but the Nix model assumes + it.</para></glossdef> + +</glossentry> + + +<glossentry><glossterm>Nix expression</glossterm> + + <glossdef><para>A high-level description of software packages and + compositions thereof. Deploying software using Nix entails writing + Nix expressions for your packages. Nix expressions are translated + to derivations that are stored in the Nix store. These derivations + can then be built.</para></glossdef> + +</glossentry> + + +<glossentry xml:id="gloss-reference"><glossterm>reference</glossterm> + + <glossdef> + <para>A store path <varname>P</varname> is said to have a + reference to a store path <varname>Q</varname> if the store object + at <varname>P</varname> contains the path <varname>Q</varname> + somewhere. The <emphasis>references</emphasis> of a store path are + the set of store paths to which it has a reference. + </para> + <para>A derivation can reference other derivations and sources + (but not output paths), whereas an output path only references other + output paths. + </para> + </glossdef> + +</glossentry> + +<glossentry xml:id="gloss-reachable"><glossterm>reachable</glossterm> + + <glossdef><para>A store path <varname>Q</varname> is reachable from + another store path <varname>P</varname> if <varname>Q</varname> is in the + <link linkend="gloss-closure">closure</link> of the + <link linkend="gloss-reference">references</link> relation. + </para></glossdef> +</glossentry> + +<glossentry xml:id="gloss-closure"><glossterm>closure</glossterm> + + <glossdef><para>The closure of a store path is the set of store + paths that are directly or indirectly “reachable” from that store + path; that is, it’s the closure of the path under the <link + linkend="gloss-reference">references</link> relation. For a package, the + closure of its derivation is equivalent to the build-time + dependencies, while the closure of its output path is equivalent to its + runtime dependencies. For correct deployment it is necessary to deploy whole + closures, since otherwise at runtime files could be missing. The command + <command>nix-store -qR</command> prints out closures of store paths. + </para> + <para>As an example, if the store object at path <varname>P</varname> contains + a reference to path <varname>Q</varname>, then <varname>Q</varname> is + in the closure of <varname>P</varname>. Further, if <varname>Q</varname> + references <varname>R</varname> then <varname>R</varname> is also in + the closure of <varname>P</varname>. + </para></glossdef> + +</glossentry> + + +<glossentry xml:id="gloss-output-path"><glossterm>output path</glossterm> + + <glossdef><para>A store path produced by a derivation.</para></glossdef> + +</glossentry> + + +<glossentry xml:id="gloss-deriver"><glossterm>deriver</glossterm> + + <glossdef><para>The deriver of an <link + linkend="gloss-output-path">output path</link> is the store + derivation that built it.</para></glossdef> + +</glossentry> + + +<glossentry xml:id="gloss-validity"><glossterm>validity</glossterm> + + <glossdef><para>A store path is considered + <emphasis>valid</emphasis> if it exists in the file system, is + listed in the Nix database as being valid, and if all paths in its + closure are also valid.</para></glossdef> + +</glossentry> + + +<glossentry xml:id="gloss-user-env"><glossterm>user environment</glossterm> + + <glossdef><para>An automatically generated store object that + consists of a set of symlinks to “active” applications, i.e., other + store paths. These are generated automatically by <link + linkend="sec-nix-env"><command>nix-env</command></link>. See <xref + linkend="sec-profiles" />.</para> + + </glossdef> + +</glossentry> + + +<glossentry xml:id="gloss-profile"><glossterm>profile</glossterm> + + <glossdef><para>A symlink to the current <link + linkend="gloss-user-env">user environment</link> of a user, e.g., + <filename>/nix/var/nix/profiles/default</filename>.</para></glossdef> + +</glossentry> + + +<glossentry xml:id="gloss-nar"><glossterm>NAR</glossterm> + + <glossdef><para>A <emphasis>N</emphasis>ix + <emphasis>AR</emphasis>chive. This is a serialisation of a path in + the Nix store. It can contain regular files, directories and + symbolic links. NARs are generated and unpacked using + <command>nix-store --dump</command> and <command>nix-store + --restore</command>.</para></glossdef> + +</glossentry> + + + +</glosslist> + + +</appendix> |