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Replace hasAttr/getAttr calls with the ? and . operators

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For NixOS evaluation, this gives a ~21% reduction in the number of
values allocated and a ~4% speedup. It's also more readable.
This commit is contained in:
Eelco Dolstra
2014-10-05 01:11:06 +02:00
parent 0e120dc68f
commit 97220c973f
8 changed files with 51 additions and 55 deletions
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lib/attrsets.nix
+10 -11
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@@ -20,8 +20,8 @@ rec {
let attr = head attrPath;
in
if attrPath == [] then e
else if hasAttr attr e
then attrByPath (tail attrPath) default (getAttr attr e)
else if e ? ${attr}
then attrByPath (tail attrPath) default e.${attr}
else default;
@@ -44,8 +44,7 @@ rec {
attrVals ["a" "b" "c"] as
=> [as.a as.b as.c]
*/
attrVals = nameList: set:
map (x: getAttr x set) nameList;
attrVals = nameList: set: map (x: set.${x}) nameList;
/* Return the values of all attributes in the given set, sorted by
@@ -66,7 +65,7 @@ rec {
=> [1 2]
*/
catAttrs = builtins.catAttrs or
(attr: l: concatLists (map (s: if hasAttr attr s then [(getAttr attr s)] else []) l));
(attr: l: concatLists (map (s: if s ? ${attr} then [s.${attr}] else []) l));
/* Filter an attribute set by removing all attributes for which the
@@ -77,7 +76,7 @@ rec {
=> { foo = 1; }
*/
filterAttrs = pred: set:
listToAttrs (fold (n: ys: let v = getAttr n set; in if pred n v then [(nameValuePair n v)] ++ ys else ys) [] (attrNames set));
listToAttrs (fold (n: ys: let v = set.${n}; in if pred n v then [(nameValuePair n v)] ++ ys else ys) [] (attrNames set));
/* foldAttrs: apply fold functions to values grouped by key. Eg accumulate values as list:
@@ -87,7 +86,7 @@ rec {
foldAttrs = op: nul: list_of_attrs:
fold (n: a:
fold (name: o:
o // (listToAttrs [{inherit name; value = op (getAttr name n) (maybeAttr name nul a); }])
o // (listToAttrs [{inherit name; value = op n.${name} (maybeAttr name nul a); }])
) a (attrNames n)
) {} list_of_attrs;
@@ -133,7 +132,7 @@ rec {
=> { x = "x-foo"; y = "y-bar"; }
*/
mapAttrs = f: set:
listToAttrs (map (attr: { name = attr; value = f attr (getAttr attr set); }) (attrNames set));
listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set));
/* Like `mapAttrs', but allows the name of each attribute to be
@@ -146,7 +145,7 @@ rec {
=> { foo_x = "bar-a"; foo_y = "bar-b"; }
*/
mapAttrs' = f: set:
listToAttrs (map (attr: f attr (getAttr attr set)) (attrNames set));
listToAttrs (map (attr: f attr set.${attr}) (attrNames set));
/* Call a function for each attribute in the given set and return
@@ -158,7 +157,7 @@ rec {
=> [ "xa" "yb" ]
*/
mapAttrsToList = f: attrs:
map (name: f name (getAttr name attrs)) (attrNames attrs);
map (name: f name attrs.${name}) (attrNames attrs);
/* Like `mapAttrs', except that it recursively applies itself to
@@ -323,7 +322,7 @@ rec {
# override only the attributes that are already present in the old set
# useful for deep-overriding
overrideExisting = old: new:
old // listToAttrs (map (attr: nameValuePair attr (attrByPath [attr] (getAttr attr old) new)) (attrNames old));
old // listToAttrs (map (attr: nameValuePair attr (attrByPath [attr] old.${attr} new)) (attrNames old));
deepSeqAttrs = x: y: deepSeqList (attrValues x) y;
}