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Diffstat (limited to 'nixpkgs/doc/functions/library/attrsets.xml')
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diff --git a/nixpkgs/doc/functions/library/attrsets.xml b/nixpkgs/doc/functions/library/attrsets.xml deleted file mode 100644 index 052bfa1f6ae3..000000000000 --- a/nixpkgs/doc/functions/library/attrsets.xml +++ /dev/null @@ -1,1751 +0,0 @@ -<section xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-functions-library-attrset"> - <title>Attribute-Set Functions</title> - - <section xml:id="function-library-lib.attrsets.attrByPath"> - <title><function>lib.attrset.attrByPath</function></title> - - <subtitle><literal>attrByPath :: [String] -> Any -> AttrSet -> Any</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.attrByPath" /> - - <para> - Return an attribute from within nested attribute sets. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>attrPath</varname> - </term> - <listitem> - <para> - A list of strings representing the path through the nested attribute set <varname>set</varname>. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>default</varname> - </term> - <listitem> - <para> - Default value if <varname>attrPath</varname> does not resolve to an existing value. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The nested attributeset to select values from. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrset.attrByPath-example-value-exists"> - <title>Extracting a value from a nested attribute set</title> -<programlisting><![CDATA[ -let set = { a = { b = 3; }; }; -in lib.attrsets.attrByPath [ "a" "b" ] 0 set -=> 3 -]]></programlisting> - </example> - - <example xml:id="function-library-lib.attrset.attrByPath-example-default-value"> - <title>No value at the path, instead using the default</title> -<programlisting><![CDATA[ -lib.attrsets.attrByPath [ "a" "b" ] 0 {} -=> 0 -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.hasAttrByPath"> - <title><function>lib.attrsets.hasAttrByPath</function></title> - - <subtitle><literal>hasAttrByPath :: [String] -> AttrSet -> Bool</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.hasAttrByPath" /> - - <para> - Determine if an attribute exists within a nested attribute set. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>attrPath</varname> - </term> - <listitem> - <para> - A list of strings representing the path through the nested attribute set <varname>set</varname>. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The nested attributeset to check. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.hasAttrByPath-example"> - <title>A nested value does exist inside a set</title> -<programlisting><![CDATA[ -lib.attrsets.hasAttrByPath - [ "a" "b" "c" "d" ] - { a = { b = { c = { d = 123; }; }; }; } -=> true -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.setAttrByPath"> - <title><function>lib.attrsets.setAttrByPath</function></title> - - <subtitle><literal>setAttrByPath :: [String] -> Any -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.setAttrByPath" /> - - <para> - Create a new attribute set with <varname>value</varname> set at the nested attribute location specified in <varname>attrPath</varname>. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>attrPath</varname> - </term> - <listitem> - <para> - A list of strings representing the path through the nested attribute set. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The value to set at the location described by <varname>attrPath</varname>. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.setAttrByPath-example"> - <title>Creating a new nested attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.setAttrByPath [ "a" "b" ] 3 -=> { a = { b = 3; }; } -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.getAttrFromPath"> - <title><function>lib.attrsets.getAttrFromPath</function></title> - - <subtitle><literal>getAttrFromPath :: [String] -> AttrSet -> Value</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.getAttrFromPath" /> - - <para> - Like <xref linkend="function-library-lib.attrsets.attrByPath" /> except without a default, and it will throw if the value doesn't exist. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>attrPath</varname> - </term> - <listitem> - <para> - A list of strings representing the path through the nested attribute set <varname>set</varname>. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The nested attribute set to find the value in. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.getAttrPath-example-success"> - <title>Succesfully getting a value from an attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.getAttrFromPath [ "a" "b" ] { a = { b = 3; }; } -=> 3 -]]></programlisting> - </example> - - <example xml:id="function-library-lib.attrsets.getAttrPath-example-throw"> - <title>Throwing after failing to get a value from an attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.getAttrFromPath [ "x" "y" ] { } -=> error: cannot find attribute `x.y' -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.attrVals"> - <title><function>lib.attrsets.attrVals</function></title> - - <subtitle><literal>attrVals :: [String] -> AttrSet -> [Any]</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.attrVals" /> - - <para> - Return the specified attributes from a set. All values must exist. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>nameList</varname> - </term> - <listitem> - <para> - The list of attributes to fetch from <varname>set</varname>. Each attribute name must exist on the attrbitue set. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The set to get attribute values from. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.attrVals-example-success"> - <title>Getting several values from an attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.attrVals [ "a" "b" "c" ] { a = 1; b = 2; c = 3; } -=> [ 1 2 3 ] -]]></programlisting> - </example> - - <example xml:id="function-library-lib.attrsets.attrVals-failure"> - <title>Getting missing values from an attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.attrVals [ "d" ] { } -error: attribute 'd' missing -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.attrValues"> - <title><function>lib.attrsets.attrValues</function></title> - - <subtitle><literal>attrValues :: AttrSet -> [Any]</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.attrValues" /> - - <para> - Get all the attribute values from an attribute set. - </para> - - <para> - Provides a backwards-compatible interface of <function>builtins.attrValues</function> for Nix version older than 1.8. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>attrs</varname> - </term> - <listitem> - <para> - The attribute set. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.attrValues-example"> - <title></title> -<programlisting><![CDATA[ -lib.attrsets.attrValues { a = 1; b = 2; c = 3; } -=> [ 1 2 3 ] -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.catAttrs"> - <title><function>lib.attrsets.catAttrs</function></title> - - <subtitle><literal>catAttrs :: String -> [AttrSet] -> [Any]</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.catAttrs" /> - - <para> - Collect each attribute named `attr' from the list of attribute sets, <varname>sets</varname>. Sets that don't contain the named attribute are ignored. - </para> - - <para> - Provides a backwards-compatible interface of <function>builtins.catAttrs</function> for Nix version older than 1.9. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>attr</varname> - </term> - <listitem> - <para> - Attribute name to select from each attribute set in <varname>sets</varname>. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>sets</varname> - </term> - <listitem> - <para> - The list of attribute sets to select <varname>attr</varname> from. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.catAttrs-example"> - <title>Collect an attribute from a list of attribute sets.</title> - <para> - Attribute sets which don't have the attribute are ignored. - </para> -<programlisting><![CDATA[ -catAttrs "a" [{a = 1;} {b = 0;} {a = 2;}] -=> [ 1 2 ] - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.filterAttrs"> - <title><function>lib.attrsets.filterAttrs</function></title> - - <subtitle><literal>filterAttrs :: (String -> Any -> Bool) -> AttrSet -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.filterAttrs" /> - - <para> - Filter an attribute set by removing all attributes for which the given predicate return false. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>pred</varname> - </term> - <listitem> - <para> - <literal>String -> Any -> Bool</literal> - </para> - <para> - Predicate which returns true to include an attribute, or returns false to exclude it. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name</varname> - </term> - <listitem> - <para> - The attribute's name - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The attribute's value - </para> - </listitem> - </varlistentry> - </variablelist> - <para> - Returns <literal>true</literal> to include the attribute, <literal>false</literal> to exclude the attribute. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The attribute set to filter - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.filterAttrs-example"> - <title>Filtering an attributeset</title> -<programlisting><![CDATA[ -filterAttrs (n: v: n == "foo") { foo = 1; bar = 2; } -=> { foo = 1; } -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.filterAttrsRecursive"> - <title><function>lib.attrsets.filterAttrsRecursive</function></title> - - <subtitle><literal>filterAttrsRecursive :: (String -> Any -> Bool) -> AttrSet -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.filterAttrsRecursive" /> - - <para> - Filter an attribute set recursively by removing all attributes for which the given predicate return false. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>pred</varname> - </term> - <listitem> - <para> - <literal>String -> Any -> Bool</literal> - </para> - <para> - Predicate which returns true to include an attribute, or returns false to exclude it. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name</varname> - </term> - <listitem> - <para> - The attribute's name - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The attribute's value - </para> - </listitem> - </varlistentry> - </variablelist> - <para> - Returns <literal>true</literal> to include the attribute, <literal>false</literal> to exclude the attribute. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The attribute set to filter - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.filterAttrsRecursive-example"> - <title>Recursively filtering an attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.filterAttrsRecursive - (n: v: v != null) - { - levelA = { - example = "hi"; - levelB = { - hello = "there"; - this-one-is-present = { - this-is-excluded = null; - }; - }; - this-one-is-also-excluded = null; - }; - also-excluded = null; - } -=> { - levelA = { - example = "hi"; - levelB = { - hello = "there"; - this-one-is-present = { }; - }; - }; - } - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.foldAttrs"> - <title><function>lib.attrsets.foldAttrs</function></title> - - <subtitle><literal>foldAttrs :: (Any -> Any -> Any) -> Any -> [AttrSets] -> Any</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.foldAttrs" /> - - <para> - Apply fold function to values grouped by key. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>op</varname> - </term> - <listitem> - <para> - <literal>Any -> Any -> Any</literal> - </para> - <para> - Given a value <varname>val</varname> and a collector <varname>col</varname>, combine the two. - </para> - <variablelist> - <varlistentry> - <term> - <varname>val</varname> - </term> - <listitem> - <para> - An attribute's value - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>col</varname> - </term> - <listitem> -<!-- TODO: make this not bad, use more fold-ey terms --> - <para> - The result of previous <function>op</function> calls with other values and <function>nul</function>. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>nul</varname> - </term> - <listitem> - <para> - The null-value, the starting value. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>list_of_attrs</varname> - </term> - <listitem> - <para> - A list of attribute sets to fold together by key. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.foldAttrs-example"> - <title>Combining an attribute of lists in to one attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.foldAttrs - (n: a: [n] ++ a) [] - [ - { a = 2; b = 7; } - { a = 3; } - { b = 6; } - ] -=> { a = [ 2 3 ]; b = [ 7 6 ]; } -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.collect"> - <title><function>lib.attrsets.collect</function></title> - - <subtitle><literal>collect :: (Any -> Bool) -> AttrSet -> [Any]</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.collect" /> - - <para> - Recursively collect sets that verify a given predicate named <varname>pred</varname> from the set <varname>attrs</varname>. The recursion stops when <varname>pred</varname> returns <literal>true</literal>. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>pred</varname> - </term> - <listitem> - <para> - <literal>Any -> Bool</literal> - </para> - <para> - Given an attribute's value, determine if recursion should stop. - </para> - <variablelist> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The attribute set value. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>attrs</varname> - </term> - <listitem> - <para> - The attribute set to recursively collect. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.collect-example-lists"> - <title>Collecting all lists from an attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.collect isList { a = { b = ["b"]; }; c = [1]; } -=> [["b"] [1]] -]]></programlisting> - </example> - - <example xml:id="function-library-lib.attrsets.collect-example-outpath"> - <title>Collecting all attribute-sets which contain the <literal>outPath</literal> attribute name.</title> -<programlisting><![CDATA[ -collect (x: x ? outPath) - { a = { outPath = "a/"; }; b = { outPath = "b/"; }; } -=> [{ outPath = "a/"; } { outPath = "b/"; }] -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.nameValuePair"> - <title><function>lib.attrsets.nameValuePair</function></title> - - <subtitle><literal>nameValuePair :: String -> Any -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.nameValuePair" /> - - <para> - Utility function that creates a <literal>{name, value}</literal> pair as expected by <function>builtins.listToAttrs</function>. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>name</varname> - </term> - <listitem> - <para> - The attribute name. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The attribute value. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.nameValuePair-example"> - <title>Creating a name value pair</title> -<programlisting><![CDATA[ -nameValuePair "some" 6 -=> { name = "some"; value = 6; } -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.mapAttrs"> - <title><function>lib.attrsets.mapAttrs</function></title> - - <subtitle><literal></literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.mapAttrs" /> - - <para> - Apply a function to each element in an attribute set, creating a new attribute set. - </para> - - <para> - Provides a backwards-compatible interface of <function>builtins.mapAttrs</function> for Nix version older than 2.1. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>fn</varname> - </term> - <listitem> - <para> - <literal>String -> Any -> Any</literal> - </para> - <para> - Given an attribute's name and value, return a new value. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name</varname> - </term> - <listitem> - <para> - The name of the attribute. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The attribute's value. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.mapAttrs-example"> - <title>Modifying each value of an attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.mapAttrs - (name: value: name + "-" + value) - { x = "foo"; y = "bar"; } -=> { x = "x-foo"; y = "y-bar"; } -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.mapAttrs-prime"> - <title><function>lib.attrsets.mapAttrs'</function></title> - - <subtitle><literal>mapAttrs' :: (String -> Any -> { name = String; value = Any }) -> AttrSet -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.mapAttrs-prime" /> - - <para> - Like <function>mapAttrs</function>, but allows the name of each attribute to be changed in addition to the value. The applied function should return both the new name and value as a <function>nameValuePair</function>. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>fn</varname> - </term> - <listitem> - <para> - <literal>String -> Any -> { name = String; value = Any }</literal> - </para> - <para> - Given an attribute's name and value, return a new <link - linkend="function-library-lib.attrsets.nameValuePair">name value pair</link>. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name</varname> - </term> - <listitem> - <para> - The name of the attribute. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The attribute's value. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The attribute set to map over. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.mapAttrs-prime-example"> - <title>Change the name and value of each attribute of an attribute set</title> -<programlisting><![CDATA[ -lib.attrsets.mapAttrs' (name: value: lib.attrsets.nameValuePair ("foo_" + name) ("bar-" + value)) - { x = "a"; y = "b"; } -=> { foo_x = "bar-a"; foo_y = "bar-b"; } - - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.mapAttrsToList"> - <title><function>lib.attrsets.mapAttrsToList</function></title> - - <subtitle><literal>mapAttrsToList :: (String -> Any -> Any) -> - AttrSet -> [Any]</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.mapAttrsToList" /> - - <para> - Call <varname>fn</varname> for each attribute in the given <varname>set</varname> and return the result in a list. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>fn</varname> - </term> - <listitem> - <para> - <literal>String -> Any -> Any</literal> - </para> - <para> - Given an attribute's name and value, return a new value. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name</varname> - </term> - <listitem> - <para> - The name of the attribute. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The attribute's value. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The attribute set to map over. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.mapAttrsToList-example"> - <title>Combine attribute values and names in to a list</title> -<programlisting><![CDATA[ -lib.attrsets.mapAttrsToList (name: value: "${name}=${value}") - { x = "a"; y = "b"; } -=> [ "x=a" "y=b" ] -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.mapAttrsRecursive"> - <title><function>lib.attrsets.mapAttrsRecursive</function></title> - - <subtitle><literal>mapAttrsRecursive :: ([String] > Any -> Any) -> AttrSet -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.mapAttrsRecursive" /> - - <para> - Like <function>mapAttrs</function>, except that it recursively applies itself to attribute sets. Also, the first argument of the argument function is a <emphasis>list</emphasis> of the names of the containing attributes. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>f</varname> - </term> - <listitem> - <para> - <literal>[ String ] -> Any -> Any</literal> - </para> - <para> - Given a list of attribute names and value, return a new value. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name_path</varname> - </term> - <listitem> - <para> - The list of attribute names to this value. - </para> - <para> - For example, the <varname>name_path</varname> for the <literal>example</literal> string in the attribute set <literal>{ foo = { bar = "example"; }; }</literal> is <literal>[ "foo" "bar" ]</literal>. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The attribute's value. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The attribute set to recursively map over. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.mapAttrsRecursive-example"> - <title>A contrived example of using <function>lib.attrsets.mapAttrsRecursive</function></title> -<programlisting><![CDATA[ -mapAttrsRecursive - (path: value: concatStringsSep "-" (path ++ [value])) - { - n = { - a = "A"; - m = { - b = "B"; - c = "C"; - }; - }; - d = "D"; - } -=> { - n = { - a = "n-a-A"; - m = { - b = "n-m-b-B"; - c = "n-m-c-C"; - }; - }; - d = "d-D"; - } - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.mapAttrsRecursiveCond"> - <title><function>lib.attrsets.mapAttrsRecursiveCond</function></title> - - <subtitle><literal>mapAttrsRecursiveCond :: (AttrSet -> Bool) -> ([ String ] -> Any -> Any) -> AttrSet -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.mapAttrsRecursiveCond" /> - - <para> - Like <function>mapAttrsRecursive</function>, but it takes an additional predicate function that tells it whether to recursive into an attribute set. If it returns false, <function>mapAttrsRecursiveCond</function> does not recurse, but does apply the map function. It is returns true, it does recurse, and does not apply the map function. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>cond</varname> - </term> - <listitem> - <para> - <literal>(AttrSet -> Bool)</literal> - </para> - <para> - Determine if <function>mapAttrsRecursive</function> should recurse deeper in to the attribute set. - </para> - <variablelist> - <varlistentry> - <term> - <varname>attributeset</varname> - </term> - <listitem> - <para> - An attribute set. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>f</varname> - </term> - <listitem> - <para> - <literal>[ String ] -> Any -> Any</literal> - </para> - <para> - Given a list of attribute names and value, return a new value. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name_path</varname> - </term> - <listitem> - <para> - The list of attribute names to this value. - </para> - <para> - For example, the <varname>name_path</varname> for the <literal>example</literal> string in the attribute set <literal>{ foo = { bar = "example"; }; }</literal> is <literal>[ "foo" "bar" ]</literal>. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The attribute's value. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - The attribute set to recursively map over. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.mapAttrsRecursiveCond-example"> - <title>Only convert attribute values to JSON if the containing attribute set is marked for recursion</title> -<programlisting><![CDATA[ -lib.attrsets.mapAttrsRecursiveCond - ({ recurse ? false, ... }: recurse) - (name: value: builtins.toJSON value) - { - dorecur = { - recurse = true; - hello = "there"; - }; - dontrecur = { - converted-to- = "json"; - }; - } -=> { - dorecur = { - hello = "\"there\""; - recurse = "true"; - }; - dontrecur = "{\"converted-to\":\"json\"}"; - } - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.genAttrs"> - <title><function>lib.attrsets.genAttrs</function></title> - - <subtitle><literal>genAttrs :: [ String ] -> (String -> Any) -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.genAttrs" /> - - <para> - Generate an attribute set by mapping a function over a list of attribute names. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>names</varname> - </term> - <listitem> - <para> - Names of values in the resulting attribute set. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>f</varname> - </term> - <listitem> - <para> - <literal>String -> Any</literal> - </para> - <para> - Takes the name of the attribute and return the attribute's value. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name</varname> - </term> - <listitem> - <para> - The name of the attribute to generate a value for. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.genAttrs-example"> - <title>Generate an attrset based on names only</title> -<programlisting><![CDATA[ -lib.attrsets.genAttrs [ "foo" "bar" ] (name: "x_${name}") -=> { foo = "x_foo"; bar = "x_bar"; } - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.isDerivation"> - <title><function>lib.attrsets.isDerivation</function></title> - - <subtitle><literal>isDerivation :: Any -> Bool</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.isDerivation" /> - - <para> - Check whether the argument is a derivation. Any set with <code>{ type = "derivation"; }</code> counts as a derivation. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>value</varname> - </term> - <listitem> - <para> - The value which is possibly a derivation. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.isDerivation-example-true"> - <title>A package is a derivation</title> -<programlisting><![CDATA[ -lib.attrsets.isDerivation (import <nixpkgs> {}).ruby -=> true - ]]></programlisting> - </example> - - <example xml:id="function-library-lib.attrsets.isDerivation-example-false"> - <title>Anything else is not a derivation</title> -<programlisting><![CDATA[ -lib.attrsets.isDerivation "foobar" -=> false - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.toDerivation"> - <title><function>lib.attrsets.toDerivation</function></title> - - <subtitle><literal>toDerivation :: Path -> Derivation</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.toDerivation" /> - - <para> - Converts a store path to a fake derivation. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>path</varname> - </term> - <listitem> - <para> - A store path to convert to a derivation. - </para> - </listitem> - </varlistentry> - </variablelist> - </section> - - <section xml:id="function-library-lib.attrsets.optionalAttrs"> - <title><function>lib.attrsets.optionalAttrs</function></title> - - <subtitle><literal>optionalAttrs :: Bool -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.optionalAttrs" /> - - <para> - Conditionally return an attribute set or an empty attribute set. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>cond</varname> - </term> - <listitem> - <para> - Condition under which the <varname>as</varname> attribute set is returned. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>as</varname> - </term> - <listitem> - <para> - The attribute set to return if <varname>cond</varname> is true. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.optionalAttrs-example-true"> - <title>Return the provided attribute set when <varname>cond</varname> is true</title> -<programlisting><![CDATA[ -lib.attrsets.optionalAttrs true { my = "set"; } -=> { my = "set"; } - ]]></programlisting> - </example> - - <example xml:id="function-library-lib.attrsets.optionalAttrs-example-false"> - <title>Return an empty attribute set when <varname>cond</varname> is false</title> -<programlisting><![CDATA[ -lib.attrsets.optionalAttrs false { my = "set"; } -=> { } - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.zipAttrsWithNames"> - <title><function>lib.attrsets.zipAttrsWithNames</function></title> - - <subtitle><literal>zipAttrsWithNames :: [ String ] -> (String -> [ Any ] -> Any) -> [ AttrSet ] -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.zipAttrsWithNames" /> - - <para> - Merge sets of attributes and use the function <varname>f</varname> to merge attribute values where the attribute name is in <varname>names</varname>. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>names</varname> - </term> - <listitem> - <para> - A list of attribute names to zip. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>f</varname> - </term> - <listitem> - <para> - <literal>(String -> [ Any ] -> Any</literal> - </para> - <para> - Accepts an attribute name, all the values, and returns a combined value. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name</varname> - </term> - <listitem> - <para> - The name of the attribute each value came from. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>vs</varname> - </term> - <listitem> - <para> - A list of values collected from the list of attribute sets. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>sets</varname> - </term> - <listitem> - <para> - A list of attribute sets to zip together. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.zipAttrsWithNames-example"> - <title>Summing a list of attribute sets of numbers</title> -<programlisting><![CDATA[ -lib.attrsets.zipAttrsWithNames - [ "a" "b" ] - (name: vals: "${name} ${toString (builtins.foldl' (a: b: a + b) 0 vals)}") - [ - { a = 1; b = 1; c = 1; } - { a = 10; } - { b = 100; } - { c = 1000; } - ] -=> { a = "a 11"; b = "b 101"; } - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.zipAttrsWith"> - <title><function>lib.attrsets.zipAttrsWith</function></title> - - <subtitle><literal>zipAttrsWith :: (String -> [ Any ] -> Any) -> [ AttrSet ] -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.zipAttrsWith" /> - - <para> - Merge sets of attributes and use the function <varname>f</varname> to merge attribute values. Similar to <xref - linkend="function-library-lib.attrsets.zipAttrsWithNames" /> where all key names are passed for <varname>names</varname>. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>f</varname> - </term> - <listitem> - <para> - <literal>(String -> [ Any ] -> Any</literal> - </para> - <para> - Accepts an attribute name, all the values, and returns a combined value. - </para> - <variablelist> - <varlistentry> - <term> - <varname>name</varname> - </term> - <listitem> - <para> - The name of the attribute each value came from. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>vs</varname> - </term> - <listitem> - <para> - A list of values collected from the list of attribute sets. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>sets</varname> - </term> - <listitem> - <para> - A list of attribute sets to zip together. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.zipAttrsWith-example"> - <title>Summing a list of attribute sets of numbers</title> -<programlisting><![CDATA[ -lib.attrsets.zipAttrsWith - (name: vals: "${name} ${toString (builtins.foldl' (a: b: a + b) 0 vals)}") - [ - { a = 1; b = 1; c = 1; } - { a = 10; } - { b = 100; } - { c = 1000; } - ] -=> { a = "a 11"; b = "b 101"; c = "c 1001"; } - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.zipAttrs"> - <title><function>lib.attrsets.zipAttrs</function></title> - - <subtitle><literal>zipAttrs :: [ AttrSet ] -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.zipAttrs" /> - - <para> - Merge sets of attributes and combine each attribute value in to a list. Similar to <xref linkend="function-library-lib.attrsets.zipAttrsWith" /> where the merge function returns a list of all values. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>sets</varname> - </term> - <listitem> - <para> - A list of attribute sets to zip together. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.zipAttrs-example"> - <title>Combining a list of attribute sets</title> -<programlisting><![CDATA[ -lib.attrsets.zipAttrs - [ - { a = 1; b = 1; c = 1; } - { a = 10; } - { b = 100; } - { c = 1000; } - ] -=> { a = [ 1 10 ]; b = [ 1 100 ]; c = [ 1 1000 ]; } - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.recursiveUpdateUntil"> - <title><function>lib.attrsets.recursiveUpdateUntil</function></title> - - <subtitle><literal>recursiveUpdateUntil :: ( [ String ] -> AttrSet -> AttrSet -> Bool ) -> AttrSet -> AttrSet -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.recursiveUpdateUntil" /> - - <para> - Does the same as the update operator <literal>//</literal> except that attributes are merged until the given predicate is verified. The predicate should accept 3 arguments which are the path to reach the attribute, a part of the first attribute set and a part of the second attribute set. When the predicate is verified, the value of the first attribute set is replaced by the value of the second attribute set. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>pred</varname> - </term> - <listitem> - <para> - <literal>[ String ] -> AttrSet -> AttrSet -> Bool</literal> - </para> - <variablelist> - <varlistentry> - <term> - <varname>path</varname> - </term> - <listitem> - <para> - The path to the values in the left and right hand sides. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>l</varname> - </term> - <listitem> - <para> - The left hand side value. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>r</varname> - </term> - <listitem> - <para> - The right hand side value. - </para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>lhs</varname> - </term> - <listitem> - <para> - The left hand attribute set of the merge. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>rhs</varname> - </term> - <listitem> - <para> - The right hand attribute set of the merge. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.recursiveUpdateUntil-example"> - <title>Recursively merging two attribute sets</title> -<programlisting><![CDATA[ -lib.attrsets.recursiveUpdateUntil (path: l: r: path == ["foo"]) - { - # first attribute set - foo.bar = 1; - foo.baz = 2; - bar = 3; - } - { - #second attribute set - foo.bar = 1; - foo.quz = 2; - baz = 4; - } -=> { - foo.bar = 1; # 'foo.*' from the second set - foo.quz = 2; # - bar = 3; # 'bar' from the first set - baz = 4; # 'baz' from the second set -} - ]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.recursiveUpdate"> - <title><function>lib.attrsets.recursiveUpdate</function></title> - - <subtitle><literal>recursiveUpdate :: AttrSet -> AttrSet -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.recursiveUpdate" /> - - <para> - A recursive variant of the update operator <literal>//</literal>. The recursion stops when one of the attribute values is not an attribute set, in which case the right hand side value takes precedence over the left hand side value. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>lhs</varname> - </term> - <listitem> - <para> - The left hand attribute set of the merge. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term> - <varname>rhs</varname> - </term> - <listitem> - <para> - The right hand attribute set of the merge. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.recursiveUpdate-example"> - <title>Recursively merging two attribute sets</title> -<programlisting><![CDATA[ -recursiveUpdate - { - boot.loader.grub.enable = true; - boot.loader.grub.device = "/dev/hda"; - } - { - boot.loader.grub.device = ""; - } -=> { - boot.loader.grub.enable = true; - boot.loader.grub.device = ""; -} -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.recurseIntoAttrs"> - <title><function>lib.attrsets.recurseIntoAttrs</function></title> - - <subtitle><literal>recurseIntoAttrs :: AttrSet -> AttrSet</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.recurseIntoAttrs" /> - - <para> - Make various Nix tools consider the contents of the resulting attribute set when looking for what to build, find, etc. - </para> - - <para> - This function only affects a single attribute set; it does not apply itself recursively for nested attribute sets. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>attrs</varname> - </term> - <listitem> - <para> - An attribute set to scan for derivations. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.recurseIntoAttrs-example"> - <title>Making Nix look inside an attribute set</title> -<programlisting><![CDATA[ -{ pkgs ? import <nixpkgs> {} }: -{ - myTools = pkgs.lib.recurseIntoAttrs { - inherit (pkgs) hello figlet; - }; -} -]]></programlisting> - </example> - </section> - - <section xml:id="function-library-lib.attrsets.cartesianProductOfSets"> - <title><function>lib.attrsets.cartesianProductOfSets</function></title> - - <subtitle><literal>cartesianProductOfSets :: AttrSet -> [ AttrSet ]</literal> - </subtitle> - - <xi:include href="./locations.xml" xpointer="lib.attrsets.cartesianProductOfSets" /> - - <para> - Return the cartesian product of attribute set value combinations. - </para> - - <variablelist> - <varlistentry> - <term> - <varname>set</varname> - </term> - <listitem> - <para> - An attribute set with attributes that carry lists of values. - </para> - </listitem> - </varlistentry> - </variablelist> - - <example xml:id="function-library-lib.attrsets.cartesianProductOfSets-example"> - <title>Creating the cartesian product of a list of attribute values</title> -<programlisting><![CDATA[ -cartesianProductOfSets { a = [ 1 2 ]; b = [ 10 20 ]; } -=> [ - { a = 1; b = 10; } - { a = 1; b = 20; } - { a = 2; b = 10; } - { a = 2; b = 20; } - ] -]]></programlisting> - </example> - </section> -</section> |