diff options
author | Jacek Galowicz <jacek@galowicz.de> | 2021-01-25 16:59:46 +0100 |
---|---|---|
committer | Jacek Galowicz <jacek@galowicz.de> | 2021-01-28 23:08:59 +0100 |
commit | 123045a57056b997165be4963cbf62120a967fec (patch) | |
tree | df971067e1c59e11fba585a121f060a3a49bd93d /lib | |
parent | d9353519d70454b53c6c302205272ccac81e1b7f (diff) |
lib/attrsets: add cartesianProductOfSets function
Diffstat (limited to 'lib')
-rw-r--r-- | lib/attrsets.nix | 19 | ||||
-rw-r--r-- | lib/default.nix | 2 | ||||
-rw-r--r-- | lib/tests/misc.nix | 67 |
3 files changed, 86 insertions, 2 deletions
diff --git a/lib/attrsets.nix b/lib/attrsets.nix index d91d7a0cd47e..0ce3aaeca452 100644 --- a/lib/attrsets.nix +++ b/lib/attrsets.nix @@ -183,6 +183,24 @@ rec { 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 builtins.listToAttrs. @@ -493,5 +511,4 @@ rec { zipWithNames = zipAttrsWithNames; zip = builtins.trace "lib.zip is deprecated, use lib.zipAttrsWith instead" zipAttrsWith; - } diff --git a/lib/default.nix b/lib/default.nix index 803f1f765647..50320669e280 100644 --- a/lib/default.nix +++ b/lib/default.nix @@ -78,7 +78,7 @@ let zipAttrsWithNames zipAttrsWith zipAttrs recursiveUpdateUntil recursiveUpdate matchAttrs overrideExisting getOutput getBin getLib getDev getMan chooseDevOutputs zipWithNames zip - recurseIntoAttrs dontRecurseIntoAttrs; + recurseIntoAttrs dontRecurseIntoAttrs cartesianProductOfSets; inherit (self.lists) singleton forEach foldr fold foldl foldl' imap0 imap1 concatMap flatten remove findSingle findFirst any all count optional optionals toList range partition zipListsWith zipLists diff --git a/lib/tests/misc.nix b/lib/tests/misc.nix index 35a5801c724f..0d249968402d 100644 --- a/lib/tests/misc.nix +++ b/lib/tests/misc.nix @@ -660,4 +660,71 @@ runTests { 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; } + ]; + }; } |