Combinatory logic in CoffeeScript, JavaScript, and Python

iks.coffee

I = (x) -> x
S = (f) -> (g) -> (x) -> (f x) (g x)
K = (x) -> (y) -> x

iks.js

function I(x) {
  return x;
};

function S(f) {
  return function(g) {
    return function(x) {
      return (f(x))(g(x));
    };
  };
};

function K(x) {
  return function(y) {
    return x;
  };
};

iks.py

I = lambda x: x
S = lambda f: lambda g: lambda x: (f(x))(g(x))
K = lambda x: lambda y: x