forked from mirrors/nixpkgs
nixpkgs: Start documenting library functions in XML
Covers assert functions and about half of the attrsets functions. Some internal consistency around IDs could be improved.
This commit is contained in:
Graham Christensen
parent
f2b3bbe44e
commit
f835f77e02
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@ -69,7 +69,7 @@ highlightjs:
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cp -r "$$HIGHLIGHTJS/loader.js" highlightjs/
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manual-full.xml: ${MD_TARGETS} .version *.xml **/*.xml
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manual-full.xml: ${MD_TARGETS} .version *.xml **/*.xml **/**/*.xml
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xmllint --nonet --xinclude --noxincludenode manual.xml --output manual-full.xml
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.version:
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@ -7,7 +7,7 @@
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The nixpkgs repository has several utility functions to manipulate Nix
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expressions.
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</para>
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<xi:include href="functions/library.xml" />
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<xi:include href="functions/overrides.xml" />
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<xi:include href="functions/generators.xml" />
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<xi:include href="functions/debug.xml" />
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15
doc/functions/library.xml
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15
doc/functions/library.xml
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@ -0,0 +1,15 @@
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<section xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xml:id="sec-functions-library">
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<title>Nixpkgs Library Functions</title>
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<para>
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Nixpkgs provides a standard library at <varname>pkgs.lib</varname>, or
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through <code>import <nixpkgs/lib></code>.
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</para>
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<xi:include href="./library/asserts.xml" />
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<xi:include href="./library/attrsets.xml" />
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</section>
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113
doc/functions/library/asserts.xml
Normal file
113
doc/functions/library/asserts.xml
Normal file
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@ -0,0 +1,113 @@
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<section xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xml:id="sec-functions-library-asserts">
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<title>Assert functions</title>
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<section xml:id="function-library-lib.asserts.assertMsg">
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<title><function>lib.asserts.assertMsg</function></title>
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<subtitle><literal>assertMsg :: Bool -> String -> Bool</literal>
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</subtitle>
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<para>
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Print a trace message if <literal>pred</literal> is false.
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</para>
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<para>
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Intended to be used to augment asserts with helpful error messages.
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</para>
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<variablelist>
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<varlistentry>
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<term>
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<varname>pred</varname>
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</term>
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<listitem>
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<para>
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Condition under which the <varname>msg</varname> should
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<emphasis>not</emphasis> be printed.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>msg</varname>
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</term>
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<listitem>
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<para>
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Message to print.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<example xml:id="function-library-lib.asserts.assertMsg-example-false">
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<title>Printing when the predicate is false</title>
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<programlisting><![CDATA[
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assert lib.asserts.assertMsg ("foo" == "bar") "foo is not bar, silly"
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stderr> trace: foo is not bar, silly
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stderr> assert failed
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]]></programlisting>
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</example>
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</section>
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<section xml:id="function-library-lib.asserts.assertOneOf">
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<title><function>lib.asserts.assertOneOf</function></title>
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<subtitle><literal>assertOneOf :: String -> String ->
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StringList -> Bool</literal>
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</subtitle>
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<para>
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Specialized <function>asserts.assertMsg</function> for checking if
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<varname>val</varname> is one of the elements of <varname>xs</varname>.
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Useful for checking enums.
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</para>
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<variablelist>
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<varlistentry>
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<term>
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<varname>name</varname>
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</term>
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<listitem>
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<para>
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The name of the variable the user entered <varname>val</varname> into,
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for inclusion in the error message.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>val</varname>
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</term>
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<listitem>
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<para>
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The value of what the user provided, to be compared against the values in
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<varname>xs</varname>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>xs</varname>
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</term>
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<listitem>
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<para>
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The list of valid values.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<example xml:id="function-library-lib.asserts.assertOneOf-example">
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<title>Ensuring a user provided a possible value</title>
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<programlisting><![CDATA[
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let sslLibrary = "bearssl";
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in lib.asserts.assertOneOf "sslLibrary" sslLibrary [ "openssl" "bearssl" ];
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=> false
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stderr> trace: sslLibrary must be one of "openssl", "libressl", but is: "bearssl"
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]]></programlisting>
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</example>
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</section>
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</section>
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938
doc/functions/library/attrsets.xml
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938
doc/functions/library/attrsets.xml
Normal file
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@ -0,0 +1,938 @@
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<section xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xml:id="sec-functions-library-attrset">
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<title>Attribute-Set Functions</title>
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<section xml:id="function-library-lib.attrsets.attrByPath">
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<title><function>lib.attrset.attrByPath</function></title>
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<subtitle><literal>attrByPath :: [String] -> Any -> AttrSet</literal>
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</subtitle>
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<para>
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Return an attribute from within nested attribute sets.
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</para>
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<variablelist>
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<varlistentry>
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<term>
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<varname>attrPath</varname>
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</term>
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<listitem>
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<para>
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A list of strings representing the path through the nested attribute set
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<varname>set</varname>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>default</varname>
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</term>
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<listitem>
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<para>
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Default value if <varname>attrPath</varname> does not resolve to an
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existing value.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>set</varname>
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</term>
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<listitem>
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<para>
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The nested attributeset to select values from.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<example xml:id="function-library-lib.attrset.attrByPath-example-value-exists">
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<title>Extracting a value from a nested attribute set</title>
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<programlisting><![CDATA[
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let set = { a = { b = 3; }; };
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in lib.attrsets.attrByPath [ "a" "b" ] 0 set
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=> 3
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]]></programlisting>
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</example>
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<example xml:id="function-library-lib.attrset.attrByPath-example-default-value">
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<title>No value at the path, instead using the default</title>
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<programlisting><![CDATA[
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lib.attrsets.attrByPath [ "a" "b" ] 0 {}
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=> 0
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]]></programlisting>
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</example>
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</section>
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<section xml:id="function-library-lib.attrsets.hasAttrByPath">
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<title><function>lib.attrsets.hasAttrByPath</function></title>
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<subtitle><literal>hasAttrByPath :: [String] -> AttrSet -> Bool</literal>
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</subtitle>
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<para>
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Determine if an attribute exists within a nested attribute set.
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</para>
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<variablelist>
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<varlistentry>
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<term>
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<varname>attrPath</varname>
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</term>
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<listitem>
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<para>
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A list of strings representing the path through the nested attribute set
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<varname>set</varname>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>set</varname>
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</term>
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<listitem>
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<para>
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The nested attributeset to check.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<example xml:id="function-library-lib.attrsets.hasAttrByPath-example">
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<title>A nested value does exist inside a set</title>
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<programlisting><![CDATA[
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lib.attrsets.hasAttrByPath
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[ "a" "b" "c" "d" ]
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{ a = { b = { c = { d = 123; }; }; }; }
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=> true
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]]></programlisting>
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</example>
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</section>
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<section xml:id="function-library-lib.attrsets.setAttrByPath">
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<title><function>lib.attrsets.setAttrByPath</function></title>
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<subtitle><literal>setAttrByPath :: [String] -> Any -> AttrSet</literal>
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</subtitle>
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<para>
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Create a new attribute set with <varname>value</varname> set at the nested
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attribute location specified in <varname>attrPath</varname>.
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</para>
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<variablelist>
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<varlistentry>
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<term>
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<varname>attrPath</varname>
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</term>
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<listitem>
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<para>
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A list of strings representing the path through the nested attribute set.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>value</varname>
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</term>
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<listitem>
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<para>
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The value to set at the location described by
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<varname>attrPath</varname>.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<example xml:id="function-library-lib.attrsets.setAttrByPath-example">
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<title>Creating a new nested attribute set</title>
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<programlisting><![CDATA[
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lib.attrsets.setAttrByPath [ "a" "b" ] 3
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=> { a = { b = 3; }; }
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]]></programlisting>
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</example>
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</section>
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<section xml:id="function-library-lib.attrsets.getAttrFromPath">
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<title><function>lib.attrsets.getAttrFromPath</function></title>
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<subtitle><literal>getAttrFromPath :: [String] -> AttrSet -> Value</literal>
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</subtitle>
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<para>
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Like <xref linkend="function-library-lib.attrsets.attrByPath" /> except
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without a default, and it will throw if the value doesn't exist.
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</para>
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<variablelist>
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<varlistentry>
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<term>
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<varname>attrPath</varname>
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</term>
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<listitem>
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<para>
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A list of strings representing the path through the nested attribute set
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<varname>set</varname>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>set</varname>
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</term>
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<listitem>
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<para>
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The nested attribute set to find the value in.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<example xml:id="function-library-lib.attrsets.getAttrPath-example-success">
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<title>Succesfully getting a value from an attribute set</title>
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<programlisting><![CDATA[
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lib.attrsets.getAttrFromPath [ "a" "b" ] { a = { b = 3; }; }
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=> 3
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]]></programlisting>
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</example>
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<example xml:id="function-library-lib.attrsets.getAttrPath-example-throw">
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<title>Throwing after failing to get a value from an attribute set</title>
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<programlisting><![CDATA[
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lib.attrsets.getAttrFromPath [ "x" "y" ] { }
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=> error: cannot find attribute `x.y'
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]]></programlisting>
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</example>
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</section>
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<section xml:id="function-library-lib.attrsets.attrVals">
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<title><function>lib.attrsets.attrVals</function></title>
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<subtitle><literal>attrVals :: [String] -> AttrSet -> [Any]</literal>
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</subtitle>
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<para>
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Return the specified attributes from a set. All values must exist.
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</para>
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<variablelist>
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<varlistentry>
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<term>
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<varname>nameList</varname>
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</term>
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<listitem>
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<para>
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The list of attributes to fetch from <varname>set</varname>. Each
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attribute name must exist on the attrbitue set.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>
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<varname>set</varname>
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</term>
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<listitem>
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<para>
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The set to get attribute values from.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<example xml:id="function-library-lib.attrsets.attrVals-example-success">
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<title>Getting several values from an attribute set</title>
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<programlisting><![CDATA[
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lib.attrsets.attrVals [ "a" "b" "c" ] { a = 1; b = 2; c = 3; }
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=> [ 1 2 3 ]
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]]></programlisting>
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</example>
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<example xml:id="function-library-lib.attrsets.attrVals-failure">
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<title>Getting missing values from an attribute set</title>
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<programlisting><![CDATA[
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lib.attrsets.attrVals [ "d" ] { }
|
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error: attribute 'd' missing
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]]></programlisting>
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</example>
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</section>
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<section xml:id="function-library-lib.attrsets.attrValues">
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<title><function>lib.attrsets.attrValues</function></title>
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<subtitle><literal>attrValues :: AttrSet -> [Any]</literal>
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</subtitle>
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<para>
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Get all the attribute values from an attribute set.
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</para>
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||||
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<para>
|
||||
Provides a backwards-compatible interface of
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<function>builtins.attrValues</function> for Nix version older than 1.8.
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</para>
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||||
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<variablelist>
|
||||
<varlistentry>
|
||||
<term>
|
||||
<varname>attrs</varname>
|
||||
</term>
|
||||
<listitem>
|
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<para>
|
||||
The attribute set.
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||||
</para>
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||||
</listitem>
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||||
</varlistentry>
|
||||
</variablelist>
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||||
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||||
<example xml:id="function-library-lib.attrsets.attrValues-example">
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<title></title>
|
||||
<programlisting><![CDATA[
|
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lib.attrsets.attrValues { a = 1; b = 2; c = 3; }
|
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=> [ 1 2 3 ]
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||||
]]></programlisting>
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||||
</example>
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||||
</section>
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||||
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||||
<section xml:id="function-library-lib.attrsets.catAttrs">
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<title><function>lib.attrsets.catAttrs</function></title>
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||||
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||||
<subtitle><literal>catAttrs :: String -> AttrSet -> [Any]</literal>
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</subtitle>
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||||
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||||
<para>
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Collect each attribute named `attr' from the list of attribute sets,
|
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<varname>sets</varname>. Sets that don't contain the named attribute are
|
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ignored.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Provides a backwards-compatible interface of
|
||||
<function>builtins.catAttrs</function> for Nix version older than 1.9.
|
||||
</para>
|
||||
|
||||
<variablelist>
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<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>
|
||||
|
||||
<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>
|
||||
|
||||
<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>
|
||||
|
||||
<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>
|
||||
|
||||
<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>
|
||||
|
||||
<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>
|
||||
|
||||
<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>
|
||||
|
||||
<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>
|
||||
|
||||
<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>
|
||||
|
||||
<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>
|
||||
</section>
|
||||
</section>
|
||||
Loading…
Reference in a new issue