diff options
Diffstat (limited to 'doc/manual/builtins.xml')
| -rw-r--r-- | doc/manual/builtins.xml | 82 |
1 files changed, 41 insertions, 41 deletions
diff --git a/doc/manual/builtins.xml b/doc/manual/builtins.xml index ce21e85250..42fcd70eb1 100644 --- a/doc/manual/builtins.xml +++ b/doc/manual/builtins.xml @@ -12,9 +12,9 @@ such as <function>derivation</function>, are always in scope of every Nix expression; you can just access them right away. But to prevent polluting the namespace too much, most built-ins are not in scope. Instead, you can access them through the <varname>builtins</varname> -built-in value, which is an attribute set that contains all built-in -functions and values. For instance, <function>derivation</function> -is also available as <function>builtins.derivation</function>.</para> +built-in value, which is a set that contains all built-in functions +and values. For instance, <function>derivation</function> is also +available as <function>builtins.derivation</function>.</para> <variablelist> @@ -39,14 +39,14 @@ is also available as <function>builtins.derivation</function>.</para> <varlistentry><term><function>builtins.attrNames</function> - <replaceable>attrs</replaceable></term> + <replaceable>set</replaceable></term> - <listitem><para>Return the names of the attributes in the - attribute set <replaceable>attrs</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: + <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: <programlisting> attrValues = attrs: map (name: builtins.getAttr name attrs) (builtins.attrNames attrs);</programlisting> @@ -68,8 +68,8 @@ attrValues = attrs: map (name: builtins.getAttr name attrs) (builtins.attrNames <varlistentry><term><varname>builtins</varname></term> - <listitem><para>The attribute set <varname>builtins</varname> - contains all the built-in functions and values. You can use + <listitem><para>The set <varname>builtins</varname> contains all + the built-in functions and values. You can use <varname>builtins</varname> to test for the availability of features in the Nix installation, e.g., @@ -258,11 +258,11 @@ stdenv.mkDerivation { <varlistentry><term><function>builtins.getAttr</function> - <replaceable>s</replaceable> <replaceable>attrs</replaceable></term> + <replaceable>s</replaceable> <replaceable>set</replaceable></term> <listitem><para><function>getAttr</function> returns the attribute - named <replaceable>s</replaceable> from the attribute set - <replaceable>attrs</replaceable>. Evaluation aborts if the + named <replaceable>s</replaceable> from + <replaceable>set</replaceable>. Evaluation aborts if the attribute doesn’t exist. This is a dynamic version of the <literal>.</literal> operator, since <replaceable>s</replaceable> is an expression rather than an identifier.</para></listitem> @@ -289,15 +289,15 @@ stdenv.mkDerivation { <varlistentry><term><function>builtins.hasAttr</function> - <replaceable>s</replaceable> <replaceable>attrs</replaceable></term> + <replaceable>s</replaceable> <replaceable>set</replaceable></term> <listitem><para><function>hasAttr</function> returns - <literal>true</literal> if the attribute set - <replaceable>attrs</replaceable> has an attribute named - <replaceable>s</replaceable>, and <literal>false</literal> - otherwise. This is a dynamic version of the <literal>?</literal> - operator, since <replaceable>s</replaceable> is an expression - rather than an identifier.</para></listitem> + <literal>true</literal> if <replaceable>set</replaceable> has an + attribute named <replaceable>s</replaceable>, and + <literal>false</literal> otherwise. This is a dynamic version of + the <literal>?</literal> operator, since + <replaceable>s</replaceable> is an expression rather than an + identifier.</para></listitem> </varlistentry> @@ -331,12 +331,12 @@ stdenv.mkDerivation { <listitem><para>Load, parse and return the Nix expression in the file <replaceable>path</replaceable>. If <replaceable>path </replaceable> is a directory, the file <filename>default.nix - </filename> in that directory is loaded. Evaluation aborts if - the file doesn’t exist or contains an incorrect Nix - expression. <function>import</function> implements Nix’s module - system: you can put any Nix expression (such as an attribute set - or a function) in a separate file, and use it from Nix expressions - in other files.</para> + </filename> in that directory is loaded. Evaluation aborts if the + file doesn’t exist or contains an incorrect Nix expression. + <function>import</function> implements Nix’s module system: you + can put any Nix expression (such as a set or a function) in a + separate file, and use it from Nix expressions in other + files.</para> <para>A Nix expression loaded by <function>import</function> must not contain any <emphasis>free variables</emphasis> (identifiers @@ -383,9 +383,9 @@ x: x + 456</programlisting> <varlistentry><term><function>builtins.intersectAttrs</function> <replaceable>e1</replaceable> <replaceable>e2</replaceable></term> - <listitem><para>Return an attribute set consisting of the - attributes in the set <replaceable>e2</replaceable> that also - exist in the set <replaceable>e1</replaceable>.</para></listitem> + <listitem><para>Return a set consisting of the attributes in the + set <replaceable>e2</replaceable> that also exist in the set + <replaceable>e1</replaceable>.</para></listitem> </varlistentry> @@ -394,7 +394,7 @@ x: x + 456</programlisting> <replaceable>e</replaceable></term> <listitem><para>Return <literal>true</literal> if - <replaceable>e</replaceable> evaluates to an attribute set, and + <replaceable>e</replaceable> evaluates to a set, and <literal>false</literal> otherwise.</para></listitem> </varlistentry> @@ -490,9 +490,9 @@ x: x + 456</programlisting> <varlistentry><term><function>builtins.listToAttrs</function> <replaceable>e</replaceable></term> - <listitem><para>Construct an attribute set from a list specifying - the names and values of each attribute. Each element of the list - should be an attribute set consisting of a string-valued attribute + <listitem><para>Construct a set from a list specifying the names + and values of each attribute. Each element of the list should be + a set consisting of a string-valued attribute <varname>name</varname> specifying the name of the attribute, and an attribute <varname>value</varname> specifying its value. Example: @@ -547,7 +547,7 @@ map (x: "foo" + x) [ "bar" "bla" "abc" ]</programlisting> a package name and version. The package name is everything up to but not including the first dash followed by a digit, and the version is everything following that dash. The result is returned - in an attribute set <literal>{ name, version }</literal>. Thus, + in a set <literal>{ name, version }</literal>. Thus, <literal>builtins.parseDrvName "nix-0.12pre12876"</literal> returns <literal>{ name = "nix"; version = "0.12pre12876"; }</literal>.</para></listitem> @@ -598,12 +598,12 @@ in config.someSetting</programlisting> <varlistentry><term><function>removeAttrs</function> - <replaceable>attrs</replaceable> <replaceable>list</replaceable></term> + <replaceable>set</replaceable> <replaceable>list</replaceable></term> <listitem><para>Remove the attributes listed in - <replaceable>list</replaceable> from the attribute set - <replaceable>attrs</replaceable>. The attributes don’t have to - exist in <replaceable>attrs</replaceable>. For instance, + <replaceable>list</replaceable> from + <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> @@ -792,7 +792,7 @@ in foo</programlisting> servlet container</link>. A servlet container contains a number of servlets (<filename>*.war</filename> files) each exported under a specific URI prefix. So the servlet configuration is a list of - attribute sets containing the <varname>path</varname> and + sets containing the <varname>path</varname> and <varname>war</varname> of the servlet (<xref linkend='ex-toxml-co-servlets' />). This kind of information is difficult to communicate with the normal method of passing |