lib.recursiveUpdateUntil

Does the same as the update operator '//' except that attributes are merged until the given predicate is verified. The predicate should accept 3 arguments which are the path to reach the attribute, a part of the first attribute set and a part of the second attribute set. When the predicate is satisfied, the value of the first attribute set is replaced by the value of the second attribute set.

Inputs

pred

Predicate, taking the path to the current attribute as a list of strings for attribute names, and the two values at that path from the original arguments.

lhs

Left attribute set of the merge.

rhs

Right attribute set of the merge.

Type

recursiveUpdateUntil :: ( [ String ] -> AttrSet -> AttrSet -> Bool ) -> AttrSet -> AttrSet -> AttrSet

Examples

recursiveUpdateUntil (path: l: r: path == ["foo"]) {
  # first attribute set
  foo.bar = 1;
  foo.baz = 2;
  bar = 3;
} {
  #second attribute set
  foo.bar = 1;
  foo.quz = 2;
  baz = 4;
}

=> {
  foo.bar = 1; # 'foo.*' from the second set
  foo.quz = 2; #
  bar = 3;     # 'bar' from the first set
  baz = 4;     # 'baz' from the second set
}

Noogle detected

• lib.attrsets.recursiveUpdateUntil

recursiveUpdateUntil =
    pred:
    lhs:
    rhs:
    let f = attrPath:
      zipAttrsWith (n: values:
        let here = attrPath ++ [n]; in
        if length values == 1
        || pred here (elemAt values 1) (head values) then
          head values
        else
          f here values
      );
    in f [] [rhs lhs];