Move zip & zipWithNames from misc.nix to attrsets.nix and rename them to
zipAttrs*. Add recursiveUpdate functions based on zipAttrs. svn path=/nixpkgs/trunk/; revision=17506
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pkgs/lib
@ -173,5 +173,90 @@ rec {
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/* If the Boolean `cond' is true, return the attribute set `as',
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otherwise an empty attribute set. */
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optionalAttrs = cond: as: if cond then as else {};
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/* Merge sets of attributes and use the function f to merge attributes
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values. */
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zipAttrsWithNames = names: f: sets:
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listToAttrs (map (name: {
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inherit name;
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value = f name (catAttrs name sets);
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}) names);
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# implentation note: Common names appear multiple times in the list of
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# names, hopefully this does not affect the system because the maximal
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# laziness avoid computing twice the same expression and listToAttrs does
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# not care about duplicated attribute names.
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zipAttrsWith = f: sets: zipWithNames (concatMap attrNames sets) f sets;
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zipAttrs = zipAttrsWith (name: values: values);
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/* backward compatibility */
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zipWithNames = zipAttrsWithNames;
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zip = zipAttrsWith;
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/* Does the same as the update operator '//' except that attributes are
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merged until the given pedicate is verified. The predicate should
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except 3 arguments which are the path to reach the attribute, a part of
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the first attribute set and a part of the second attribute set. When
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the predicate is verified, the value of the first attribute set is
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replaced by the value of the second attribute set.
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Example:
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recursiveUpdateUntil (path: l: r: path == ["foo"]) {
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# first attribute set
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foo.bar = 1;
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foo.baz = 2;
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bar = 3;
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} {
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#second attribute set
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foo.bar = 1;
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foo.quz = 2;
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baz = 4;
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}
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returns: {
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foo.bar = 1; # 'foo.*' from the second set
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foo.quz = 2; #
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bar = 3; # 'bar' from the first set
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baz = 4; # 'baz' from the second set
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}
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*/
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recursiveUpdateUntil = pred: lhs: rhs:
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let f = attrPath:
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zipAttrsWith (n: values:
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if tail values == []
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|| pred attrPath (head (tail values)) (head values) then
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head values
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else
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f (attrPath ++ [n]) values
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);
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in f [] [rhs lhs];
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/* Does the same as the update operator '//' and keep siblings attribute.
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This recusion stop when one of the attribute value is not an attribute
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set, in which case the right hand side value takes precedence over the
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left hand side value.
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Example:
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recursiveUpdate {
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boot.loader.grub.enable = true;
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boot.loader.grub.device = "/dev/hda";
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} {
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boot.loader.grub.device = "";
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}
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returns: {
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boot.loader.grub.enable = true;
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boot.loader.grub.device = "";
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}
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*/
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recursiveUpdate = lhs: rhs:
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recursiveUpdateUntil (path: lhs: rhs:
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!(isAttrs lhs && isAttrs rhs)
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) lhs rhs;
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}
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@ -197,20 +197,6 @@ rec {
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else condConcat
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name (tail (tail list)) checker;
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# Merge sets of attributes and use the function f to merge
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# attributes values.
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zip = f: sets:
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zipWithNames (concatMap builtins.attrNames sets) f sets;
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zipWithNames = names: f: sets:
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builtins.listToAttrs (map (name: {
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inherit name;
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value =
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f name
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(map (__getAttr name)
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(filter (__hasAttr name) sets));
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}) names);
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lazyGenericClosure = {startSet, operator}:
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let
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work = list: doneKeys: result:
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