lib.trivial.genericClosure

Takes 1 arguments

attrset

Takes an attrset with the following attributes:

• startSet [ Item ]
  • A list of start items. Each item must be an attrset containing a key. The key must be comparable.
• operator Item -> [ Item ]
  • A function

returns a list of attrsets

GenericClosure starts with the startSet and recursively applying the operator function to each item. The attrsets in the startSet and the attrsets produced by operator must contain a value named key which is comparable. The result is produced by calling operator for each item with a value for key that has not been called yet including newly produced items. The function terminates when no new items are produced. The resulting list of attrsets contains only attrsets with a unique key. For example,

builtins.genericClosure {
  startSet = [ {key = 5;} ];
  operator = item: [{
    key = if (item.key / 2 ) * 2 == item.key
         then item.key / 2
         else 3 * item.key + 1;
  }];
}

evaluates to

[ { key = 5; } { key = 16; } { key = 8; } { key = 4; } { key = 2; } { key = 1; } ]

Noogle detected

• builtins.genericClosure
• lib.genericClosure

genericClosure :: AttrSet -> [AttrSet]