lib/attrsets: add cartesianProductOfSets function

This commit is contained in:
Jacek Galowicz 2021-01-25 16:59:46 +01:00
parent d9353519d7
commit 123045a570
4 changed files with 125 additions and 2 deletions

View file

@ -1711,4 +1711,43 @@ recursiveUpdate
</example> </example>
</section> </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> </section>

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@ -183,6 +183,24 @@ rec {
else else
[]; [];
/* Return the cartesian product of attribute set value combinations.
Example:
cartesianProductOfSets { a = [ 1 2 ]; b = [ 10 20 ]; }
=> [
{ a = 1; b = 10; }
{ a = 1; b = 20; }
{ a = 2; b = 10; }
{ a = 2; b = 20; }
]
*/
cartesianProductOfSets = attrsOfLists:
lib.foldl' (listOfAttrs: attrName:
concatMap (attrs:
map (listValue: attrs // { ${attrName} = listValue; }) attrsOfLists.${attrName}
) listOfAttrs
) [{}] (attrNames attrsOfLists);
/* Utility function that creates a {name, value} pair as expected by /* Utility function that creates a {name, value} pair as expected by
builtins.listToAttrs. builtins.listToAttrs.
@ -493,5 +511,4 @@ rec {
zipWithNames = zipAttrsWithNames; zipWithNames = zipAttrsWithNames;
zip = builtins.trace zip = builtins.trace
"lib.zip is deprecated, use lib.zipAttrsWith instead" zipAttrsWith; "lib.zip is deprecated, use lib.zipAttrsWith instead" zipAttrsWith;
} }

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@ -78,7 +78,7 @@ let
zipAttrsWithNames zipAttrsWith zipAttrs recursiveUpdateUntil zipAttrsWithNames zipAttrsWith zipAttrs recursiveUpdateUntil
recursiveUpdate matchAttrs overrideExisting getOutput getBin recursiveUpdate matchAttrs overrideExisting getOutput getBin
getLib getDev getMan chooseDevOutputs zipWithNames zip getLib getDev getMan chooseDevOutputs zipWithNames zip
recurseIntoAttrs dontRecurseIntoAttrs; recurseIntoAttrs dontRecurseIntoAttrs cartesianProductOfSets;
inherit (self.lists) singleton forEach foldr fold foldl foldl' imap0 imap1 inherit (self.lists) singleton forEach foldr fold foldl foldl' imap0 imap1
concatMap flatten remove findSingle findFirst any all count concatMap flatten remove findSingle findFirst any all count
optional optionals toList range partition zipListsWith zipLists optional optionals toList range partition zipListsWith zipLists

View file

@ -660,4 +660,71 @@ runTests {
expected = [ [ "foo" ] [ "foo" "<name>" "bar" ] [ "foo" "bar" ] ]; expected = [ [ "foo" ] [ "foo" "<name>" "bar" ] [ "foo" "bar" ] ];
}; };
testCartesianProductOfEmptySet = {
expr = cartesianProductOfSets {};
expected = [ {} ];
};
testCartesianProductOfOneSet = {
expr = cartesianProductOfSets { a = [ 1 2 3 ]; };
expected = [ { a = 1; } { a = 2; } { a = 3; } ];
};
testCartesianProductOfTwoSets = {
expr = cartesianProductOfSets { a = [ 1 ]; b = [ 10 20 ]; };
expected = [
{ a = 1; b = 10; }
{ a = 1; b = 20; }
];
};
testCartesianProductOfTwoSetsWithOneEmpty = {
expr = cartesianProductOfSets { a = [ ]; b = [ 10 20 ]; };
expected = [ ];
};
testCartesianProductOfThreeSets = {
expr = cartesianProductOfSets {
a = [ 1 2 3 ];
b = [ 10 20 30 ];
c = [ 100 200 300 ];
};
expected = [
{ a = 1; b = 10; c = 100; }
{ a = 1; b = 10; c = 200; }
{ a = 1; b = 10; c = 300; }
{ a = 1; b = 20; c = 100; }
{ a = 1; b = 20; c = 200; }
{ a = 1; b = 20; c = 300; }
{ a = 1; b = 30; c = 100; }
{ a = 1; b = 30; c = 200; }
{ a = 1; b = 30; c = 300; }
{ a = 2; b = 10; c = 100; }
{ a = 2; b = 10; c = 200; }
{ a = 2; b = 10; c = 300; }
{ a = 2; b = 20; c = 100; }
{ a = 2; b = 20; c = 200; }
{ a = 2; b = 20; c = 300; }
{ a = 2; b = 30; c = 100; }
{ a = 2; b = 30; c = 200; }
{ a = 2; b = 30; c = 300; }
{ a = 3; b = 10; c = 100; }
{ a = 3; b = 10; c = 200; }
{ a = 3; b = 10; c = 300; }
{ a = 3; b = 20; c = 100; }
{ a = 3; b = 20; c = 200; }
{ a = 3; b = 20; c = 300; }
{ a = 3; b = 30; c = 100; }
{ a = 3; b = 30; c = 200; }
{ a = 3; b = 30; c = 300; }
];
};
} }