Learn X By Example
Learn X By Example

    Go by Example: Closures

    Go by Example : Closures

    Go supports anonymous functions , which can form closures . Anonymous functions are useful when you want to define a function inline without having to name it.

    package main
    import "fmt"

    This function intSeq returns another function, which we define anonymously in the body of intSeq . The returned function closes over the variable i to form a closure.

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

    We call intSeq , assigning the result (a function) to nextInt . This function value captures its own i value, which will be updated each time we call nextInt .

        nextInt := intSeq()

    See the effect of the closure by calling nextInt a few times.

        fmt.Println(nextInt())
    fmt.Println(nextInt())
    fmt.Println(nextInt())

    To confirm that the state is unique to that particular function, create and test a new one.

        newInts := intSeq()
    fmt.Println(newInts())
}
    $ go run closures.go
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    The last feature of functions we’ll look at for now is recursion.

    Next example: Recursion .

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