{ lib, ... }:
with lib;
with builtins; rec {
  readLines = f: init (filter isString (split "\n" (readFile f)));
  splitWhitespace = s: filter isString (builtins.split "[[:space:]]+" s);
  abs = i: if i >= 0 then i else i * -1;
  delta = x: y: abs (x - y);
  listSum = foldl' add 0;
  deleteAt = l: i: (take i l) ++ (drop (i + 1) l);
  eq = x: y: x == y;
  greaterThan = x: y: x > y;
  listRange = l: range 0 (length l);
}