anchor.diff:                [ (elemAt list n) ] ++ take' (n + 1);
           in take' 0;
   
  -
  -  # Remove the first (at most) N elements of a list.
  +  /* Remove the first (at most) N elements of a list.
  +
  +     Example:
  +       drop 2 [ "a" "b" "c" "d" ]
  +       => [ "c" "d" ]
  +       drop 2 [ ]
  +       => [ ]
  +  */
     drop =
       if builtins ? genList then
         count: list: sublist count (length list) list
  
positive.code:         else op (foldl' (n - 1)) (elemAt list n);
      in foldl' (length list - 1);
  
  
    # Strict version of foldl.
    foldl' = builtins.foldl' or foldl;
  
  
    # Map with index: `imap (i: v: "${v}-${toString i}") ["a" "b"] ==
    # ["a-1" "b-2"]'. FIXME: why does this start to count at 1?
    imap =
      if builtins ? genList then
        f: list: genList (n: f (n + 1) (elemAt list n)) (length list)
  
negative.code:       if len < 2 then list
        else (sort strictLess pivot.left) ++  [ first ] ++  (sort strictLess pivot.right));
  
    /* Return the first (at most) N elements of a list.
  
       Example:
         take 2 [ "a" "b" "c" "d" ]
         => [ "a" "b" ]
         take 2 [ ]
         => [ ]
    */
    take =
      if builtins ? genList then
        count: sublist 0 count
  