diff options
Diffstat (limited to 'doc/manual')
| -rw-r--r-- | doc/manual/build-farm.xml | 10 | ||||
| -rw-r--r-- | doc/manual/writing-nix-expressions.xml | 63 |
2 files changed, 35 insertions, 38 deletions
diff --git a/doc/manual/build-farm.xml b/doc/manual/build-farm.xml index dc27d1cff00f..4745d205c515 100644 --- a/doc/manual/build-farm.xml +++ b/doc/manual/build-farm.xml @@ -14,10 +14,10 @@ build farm, since: instance, if you perform a build for a <literal>powerpc-darwin</literal> on an <literal>i686-linux</literal> machine, Nix can automatically forward - to build to a <literal>powerpc-darwin</literal> machine, if + the build to a <literal>powerpc-darwin</literal> machine, if available.</para></listitem> - <listitem><para>The Nix expression language is ideal for providing + <listitem><para>The Nix expression language is ideal for describing build jobs, plus all their dependencies. For instance, if your package has some dependency, you don't have to manually install it on all the machines in the build farm; they will be built @@ -26,9 +26,9 @@ build farm, since: <listitem><para>Proper release management requires that builds (if deployed) are traceable: it should be possible to figure out from exactly what sources they were built, in what configuration, etc.; - and it should be possible to reproduce the build, if necessary. - Nix's hashing scheme uniquely identifies builds, and Nix expressions - are self-contained.</para></listitem> + and it should be possible to reproduce the build, if necessary. Nix + makes this possible since Nix's hashing scheme uniquely identifies + builds, and Nix expressions are self-contained.</para></listitem> <listitem><para>Nix will only rebuild things that have actually changed. For instance, if the sources of a component haven't diff --git a/doc/manual/writing-nix-expressions.xml b/doc/manual/writing-nix-expressions.xml index d29f76f19aef..dae7d9073b38 100644 --- a/doc/manual/writing-nix-expressions.xml +++ b/doc/manual/writing-nix-expressions.xml @@ -83,9 +83,7 @@ the single Nix expression in that directory would expect in a basic Unix environment: a C/C++ compiler (GCC, to be precise), the Bash shell, fundamental Unix tools such as <command>cp</command>, <command>grep</command>, - <command>tar</command>, etc. (See - <filename>pkgs/stdenv/nix/path.nix</filename> to see what's in - <command>stdenv</command>.) <varname>fetchurl</varname> is a + <command>tar</command>, etc. <varname>fetchurl</varname> is a function that downloads files. <varname>perl</varname> is the Perl interpreter.</para> @@ -109,12 +107,12 @@ the single Nix expression in that directory <varname>mkDerivation</varname> is a function provided by <varname>stdenv</varname> that builds a component from a set of <emphasis>attributes</emphasis>. An attribute set is just a list - of key/value pairs where the value is an arbitrary Nix expression. - They take the general form + of key/value pairs where each value is an arbitrary Nix + expression. They take the general form <literal>{<replaceable>name1</replaceable> = <replaceable>expr1</replaceable>; <replaceable>...</replaceable> - <replaceable>name1</replaceable> = - <replaceable>expr1</replaceable>;</literal>.</para> + <replaceable>nameN</replaceable> = + <replaceable>exprN</replaceable>;}</literal>.</para> </callout> @@ -148,11 +146,11 @@ the single Nix expression in that directory <para>The builder has to know what the sources of the component are. Here, the attribute <varname>src</varname> is bound to the result of a call to the <command>fetchurl</command> function. - Given a URL and a MD5 hash of the expected contents of the file at - that URL, this function actually builds a derivation that - downloads the file and checks its hash. So the sources are a - dependency that like all other dependencies is built before Hello - itself is built.</para> + Given a URL and an MD5 hash of the expected contents of the file + at that URL, this function builds a derivation that downloads the + file and checks its hash. So the sources are a dependency that + like all other dependencies is built before Hello itself is + built.</para> <para>Instead of <varname>src</varname> any other name could have been used, and in fact there can be any number of sources (bound @@ -172,7 +170,7 @@ the single Nix expression in that directory <programlisting> perl = perl;</programlisting> - will do the trink: it binds an attribute <varname>perl</varname> + will do the trick: it binds an attribute <varname>perl</varname> to the function argument which also happens to be called <varname>perl</varname>. However, it looks a bit silly, so there is a shorter syntax. The <literal>inherit</literal> keyword @@ -218,7 +216,8 @@ steps:</para> <callout arearefs='ex-hello-builder-co-1'> <para>When Nix runs a builder, it initially completely clears the - environment. For instance, the <envar>PATH</envar> variable is + environment (except for the attributes declared in the + derivation). For instance, the <envar>PATH</envar> variable is empty<footnote><para>Actually, it's initialised to <filename>/path-not-set</filename> to prevent Bash from setting it to a default value.</para></footnote>. This is done to prevent @@ -596,13 +595,11 @@ language. Purity means that operations in the language don't have side-effects (for instance, there is no variable assignment). Laziness means that arguments to functions are evaluated only when they are needed. Functional means that functions are -<quote>normal</quote> values that can be passed around and -manipulated in interesting ways.</para> - -<para>The language is not a full-featured, general purpose language. -It's main job is to describe components, compositions of components, -and the variability within components. For this a functional language -is perfectly suited.</para> +<quote>normal</quote> values that can be passed around and manipulated +in interesting ways. The language is not a full-featured, general +purpose language. It's main job is to describe components, +compositions of components, and the variability within +components.</para> <para>This section presents the various features of the language.</para> @@ -773,7 +770,7 @@ and evaluates to <literal>"foobar"</literal>. <simplesect><title>Inheriting attributes</title> -<para>When defining an attribute set itt is often convenient to copy +<para>When defining an attribute set it is often convenient to copy variables from the surrounding lexical scope (e.g., when you want to propagate attributes). This can be shortened using the <literal>inherit</literal> keyword. For instance, @@ -849,7 +846,7 @@ let { </para> <para>It is also possible to define a function that takes a single -argument and that does need to be called with an attribute set as +argument and that does not need to be called with an attribute set as argument. The syntax is <programlisting> @@ -959,10 +956,10 @@ used in the Nix expression for Subversion.</para> <callout arearefs='ex-subversion-nix-co-2'> <para>This assertion says that in order for Subversion to have SSL support (so that it can access <literal>https</literal> URLs), an - OpenSSL library must be passed. Additionally, it says + OpenSSL library must be passed. Additionally, it says that <emphasis>if</emphasis> Apache support is enabled, then Apache's - OpenSSL should much Subversion's. (Note that if Apache support is - not enabled, we don't care about Apache's OpenSSL.)</para> + OpenSSL should match Subversion's. (Note that if Apache support + is not enabled, we don't care about Apache's OpenSSL.)</para> </callout> <callout arearefs='ex-subversion-nix-co-4'> @@ -1241,14 +1238,14 @@ command-line argument. See <xref linkend='sec-standard-environment' written to <filename>/nix/var/log/nix</filename>.</para></listitem> <listitem><para>The builder is executed with the arguments specified - by the attribute <varname>args</varname>. If it exit with exit code - 0, it is considered to have succeeded.</para></listitem> + by the attribute <varname>args</varname>. If it exits with exit + code 0, it is considered to have succeeded.</para></listitem> <listitem><para>The temporary directory is removed (unless the <option>-K</option> option was specified).</para></listitem> - <listitem><para>If the build was succesful, Nix scans the output for - references to the paths of the inputs. These so-called + <listitem><para>If the build was successful, Nix scans the output + for references to the paths of the inputs. These so-called <emphasis>retained dependencies</emphasis> could be used when the output of the derivation is used (e.g., when it's executed or used as input to another derivation), so if we deploy the derivation, we @@ -1406,7 +1403,7 @@ variable. The phases are: <listitem> - <para><function>unpackPhase</function>: unpacks the source files + <para><function>unpackPhase</function> unpacks the source files listed in the <envar>src</envar> environment variable to the current directory. It supports <filename>tar</filename> files, optionally compressed with <command>gzip</command> or @@ -1415,7 +1412,7 @@ variable. The phases are: environment; you should add it as a build input yourself); and unpacked source trees (i.e., directories; they are copied verbatim). You can add support for other file types by setting - the <varname>findUnpacker</varname> hook. This hook should set an + the <varname>findUnpacker</varname> hook. This hook should set the variable <varname>unpackCmd</varname> to contain the command to be executed to unpack the file.</para> @@ -1441,7 +1438,7 @@ variable. The phases are: <para><function>configurePhase</function> runs the script called <filename>configure</filename> in the current directory with a <option>--prefix</option> set to the output path. You can add - additional flag through the <varname>configureFlags</varname> + additional flags through the <varname>configureFlags</varname> variable. If <filename>configure</filename> does not exist, nothing happens.</para> |