diff options
Diffstat (limited to 'pkgs/lib/attrsets.nix')
-rw-r--r-- | pkgs/lib/attrsets.nix | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/pkgs/lib/attrsets.nix b/pkgs/lib/attrsets.nix index db4b9fb210c6..260c61558a4e 100644 --- a/pkgs/lib/attrsets.nix +++ b/pkgs/lib/attrsets.nix @@ -126,12 +126,25 @@ rec { Example: mapAttrs (name: value: name + "-" + value) - {x = "foo"; y = "bar";} - => {x = "x-foo"; y = "y-bar";} + { x = "foo"; y = "bar"; } + => { x = "x-foo"; y = "y-bar"; } */ mapAttrs = f: set: listToAttrs (map (attr: nameValuePair attr (f attr (getAttr attr set))) (attrNames set)); - + + + /* Like `mapAttrs', 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 `nameValuePair'. + + Example: + mapAttrs' (name: value: nameValuePair ("foo_" + name) ("bar-" + value)) + { x = "a"; y = "b"; } + => { foo_x = "bar-a"; foo_y = "bar-b"; } + */ + mapAttrs' = f: set: + listToAttrs (map (attr: f attr (getAttr attr set)) (attrNames set)); + /* Like `mapAttrs', except that it recursively applies itself to attribute sets. Also, the first argument of the argument |