diff options
Diffstat (limited to 'doc/manual/expressions/builtins.xml')
| -rw-r--r-- | doc/manual/expressions/builtins.xml | 64 |
1 files changed, 52 insertions, 12 deletions
diff --git a/doc/manual/expressions/builtins.xml b/doc/manual/expressions/builtins.xml index 4edb3a1a76fb..3cdf4e28fe6a 100644 --- a/doc/manual/expressions/builtins.xml +++ b/doc/manual/expressions/builtins.xml @@ -45,14 +45,17 @@ available as <function>builtins.derivation</function>.</para> <listitem><para>Return the names of the attributes in the set <replaceable>set</replaceable> in a sorted list. For instance, <literal>builtins.attrNames { y = 1; x = "foo"; }</literal> - evaluates to <literal>[ "x" "y" ]</literal>. There is no built-in - function <function>attrValues</function>, but you can easily - define it yourself: + evaluates to <literal>[ "x" "y" ]</literal>.</para></listitem> -<programlisting> -attrValues = set: map (name: builtins.getAttr name set) (builtins.attrNames set);</programlisting> + </varlistentry> - </para></listitem> + + <varlistentry><term><function>builtins.attrValues</function> + <replaceable>set</replaceable></term> + + <listitem><para>Return the values of the attributes in the set + <replaceable>set</replaceable> in the order corresponding to the + sorted attribute names.</para></listitem> </varlistentry> @@ -144,6 +147,19 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting> --> + <varlistentry><term><function>builtins.deepSeq</function> + <replaceable>e1</replaceable> <replaceable>e2</replaceable></term> + + <listitem><para>This is like <literal>seq + <replaceable>e1</replaceable> + <replaceable>e2</replaceable></literal>, except that + <replaceable>e1</replaceable> is evaluated + <emphasis>deeply</emphasis>: if it’s a list or set, its elements + or attributes are also evaluated recursively.</para></listitem> + + </varlistentry> + + <varlistentry><term><function>derivation</function> <replaceable>attrs</replaceable></term> @@ -596,13 +612,26 @@ in config.someSetting</programlisting> </varlistentry> - <!-- - <varlistentry><term><function>relativise</function></term> + <varlistentry><term><function>builtins.readDir</function> + <replaceable>path</replaceable></term> - <listitem><para>TODO</para></listitem> + <listitem><para>Return the contents of the directory + <replaceable>path</replaceable> as a set mapping directory entries + to the corresponding file type. For instance, if directory + <filename>A</filename> contains a regular file + <filename>B</filename> and another directory + <filename>C</filename>, then <literal>builtins.readDir + ./A</literal> will return the set + +<programlisting> +{ A = "regular"; B = "directory"; }</programlisting> + + The possible values for the file type are + <literal>"regular"</literal>, <literal>"directory"</literal>, + <literal>"symlink"</literal> and + <literal>"unknown"</literal>.</para></listitem> </varlistentry> - --> <varlistentry><term><function>builtins.readFile</function> @@ -622,14 +651,25 @@ in config.someSetting</programlisting> <replaceable>set</replaceable>. The attributes don’t have to exist in <replaceable>set</replaceable>. For instance, -<screen> -removeAttrs { x = 1; y = 2; z = 3; } [ "a" "x" "z" ]</screen> +<programlisting> +removeAttrs { x = 1; y = 2; z = 3; } [ "a" "x" "z" ]</programlisting> evaluates to <literal>{ y = 2; }</literal>.</para></listitem> </varlistentry> + <varlistentry><term><function>builtins.seq</function> + <replaceable>e1</replaceable> <replaceable>e2</replaceable></term> + + <listitem><para>Evaluate <replaceable>e1</replaceable>, then + evaluate and return <replaceable>e2</replaceable>. This ensures + that a computation is strict in the value of + <replaceable>e1</replaceable>.</para></listitem> + + </varlistentry> + + <varlistentry><term><function>builtins.stringLength</function> <replaceable>e</replaceable></term> |