calling the variable, as in function statements in JavaScript. Since languages that allow anonymous functions generally allow assigning these functions to variables (if not first-class functions), many languages do not provide a way to refer to the function itself, and explicitly reject anonymous recursion; examples include Go. For example, in JavaScript the factorial function can be defined via anonymous recursion as such: [1, 2, 3, 4, 5].map(function(n) { return (!(n > 1)) ? 1 : arguments.callee(n-1) * n; }); Rewritten to use a named function expression yields: [1, 2, 3, 4, 5].map(function factorial(n) { return (!(n > 1)) ? 1 : factorial(n-1) * n; }); Passing functions as arguments Even without mechanisms to refer to the current function or calling function, anonymous recursion is possible in a language that allows functions as arguments. This is done by adding another parameter to the basic recursive function and using this parameter as the function for the recursive call. This creates a higher-order function, and passing this higher function itself allows anonymous recursion within the actual recursive function. This can be done purely anonymously by applying a fixed-point combinator to this higher order function. This is mainly of academic interest, particularly to show that the lambda calculus has recursion, as the resulting expression is significantly more complicated than the original named recursive function. Conversely, the use of fixed-pointed combinators may be generically referred to as "anonymous recursion", as this is a notable use of them, though they have other applications. This is illustrated below using Python. First, a standard named recursion: def fact(n): if n == 0: return 1 return n * fact(n - 1) Using a higher-order function so the top-level function recurses anonymously on an argument, but still needing the standard recursive function as an argument: def fact0(n0): if n0 == 0: return 1 return n0 * fact0(n0 - 1) fact1 = lambda f, n1: 1 if n1 == 0 else n1 * f(n1 - 1) fact = lambda n: fact1(fact0, n) We can eliminate the standard recursive function by passing the function argument into the call: fact1 = lambda f, n1: 1 if n1 == 0 else n1 * f(f, n1 - 1) fact = lambda n: fact1(fact1, n) The second line can be replaced by a generic higher-order function called a combinator: F = lambda f: (lambda x: f(f, x)) fact1 = lambda f, n1: 1 if n1 ==