Anonymous Functions

Anonymous functions are function definitions that are not bound to an identifier.

• are often arguments being passed to higher-order functions
• used for constructing result of a higher-order function that returns a function

It is syntactically lighter than a regular function, for one-time use functions.

Closure

Closures are a technique for implementing lexically scoped name binding in languages with first-class functions.

• a closure is a record storing a function together with an environment

func intSeq() func() int {
    i := 0
    return func() int {
        i += 1
        return i
    }
}

A function that returns another function that closes over the variable i to form a closure.

• the value of i persists in the environment defined by intSeq()