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lib/attrset: miscellaneous optimizations

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- Eta reduce `mapAttrsRecursiveCond`, `foldAttrs`, `getAttrFromPath`.
- Modify `matchAttrs` to use `elemAt` instead of `head (tail xs)` to access
  elements.
- Modify `matchAttrs` to use `any id` instead of `foldr and true`.
This commit is contained in:
polykernel 2021-12-27 17:53:15 -05:00
parent a54f2231c9
commit 63ce7d3184
1 changed files with 10 additions and 10 deletions
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20
lib/attrsets.nix
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@ -3,9 +3,9 @@
let
inherit (builtins) head tail length;
inherit (lib.trivial) and;
inherit (lib.trivial) id;
inherit (lib.strings) concatStringsSep sanitizeDerivationName;
inherit (lib.lists) foldr foldl' concatMap concatLists elemAt;
inherit (lib.lists) foldr foldl' concatMap concatLists elemAt all;
in
rec {
@ -73,9 +73,9 @@ rec {
getAttrFromPath ["z" "z"] x
=> error: cannot find attribute `z.z'
*/
getAttrFromPath = attrPath: set:
getAttrFromPath = attrPath:
let errorMsg = "cannot find attribute `" + concatStringsSep "." attrPath + "'";
in attrByPath attrPath (abort errorMsg) set;
in attrByPath attrPath (abort errorMsg);
/* Return the specified attributes from a set.
@ -154,12 +154,12 @@ rec {
foldAttrs (n: a: [n] ++ a) [] [{ a = 2; } { a = 3; }]
=> { a = [ 2 3 ]; }
*/
foldAttrs = op: nul: list_of_attrs:
foldAttrs = op: nul:
foldr (n: a:
foldr (name: o:
o // { ${name} = op n.${name} (a.${name} or nul); }
) a (attrNames n)
) {} list_of_attrs;
) {};
/* Recursively collect sets that verify a given predicate named `pred'
@ -295,14 +295,14 @@ rec {
*/
mapAttrsRecursiveCond = cond: f: set:
let
recurse = path: set:
recurse = path:
let
g =
name: value:
if isAttrs value && cond value
then recurse (path ++ [name]) value
else f (path ++ [name]) value;
in mapAttrs g set;
in mapAttrs g;
in recurse [] set;
@ -455,8 +455,8 @@ rec {
=> true
*/
matchAttrs = pattern: attrs: assert isAttrs pattern;
foldr and true (attrValues (zipAttrsWithNames (attrNames pattern) (n: values:
let pat = head values; val = head (tail values); in
all id (attrValues (zipAttrsWithNames (attrNames pattern) (n: values:
let pat = head values; val = elemAt values 1; in
if length values == 1 then false
else if isAttrs pat then isAttrs val && matchAttrs pat val
else pat == val