Cursed Nix Koans

A slight variant:

let
  __div = x: y: y x;
in
  builtins.readDir "/etc" / builtins.attrNames / builtins.length
let
  __mul = x: y: if builtins.typeOf y != "lambda"
    then x y
    else z: x (y z);
in 
  builtins.length * builtins.attrNames * builtins.readDir "/etc"

source:[spoiler]Add an infix reverse-application operator · Issue #2118 · NixOS/nix · GitHub