Deep Dive into Closures in Go: Theoretical Foundations and Practical Applications

000_README.md

Deep Dive into Closures in Go: Theoretical Foundations and Practical Applications

This Gist contains all the code examples from the article Deep Dive into Closures in Go: Theoretical Foundations and Practical Applications. The article explores closures in Go, delving into both the theoretical underpinnings and practical applications.

01.go

func outer() {
    a := 10
    if true {
        b := 20
        fmt.Println(a, b) // a and b are visible here
    }
    fmt.Println(a) // a is visible here
    // fmt.Println(b) // b is not visible here, this would cause a compile error
}

02.go

int* createPointer() {
    int x = 10;
    return &x; // Unsafe: x is allocated on the stack
}

03.go

func createPointer() *int {
    x := 10
    return &x // Safe: x will be allocated on the heap
}

04.go

func fib() func() int {
    a, b := 0, 1
    return func() int {
        a, b = b, a+b
        return a
    }
}

06.go

func main() {
    a := 10
    if true {
        b := 20
        {
            c := 30
            fmt.Println(a, b, c) // All three variables are visible here
        }
        // fmt.Println(c) // c is not visible here, this would cause a compile error
    }
    // fmt.Println(b) // b is not visible here, this would cause a compile error
    fmt.Println(a) // Only a is visible here
}

07.go

func outer() {
    x := 10
    inner := func() {
        fmt.Println(x) // Refers to x in outer
    }
    inner()
}

func main() {
    x := 20
    outer() // Prints 10, not 20
}

08.go

func main() {
    for i := 0; i < 3; i++ {
        go func() {
            fmt.Println(i)
        }()
    }
    time.Sleep(time.Second) // Give goroutines time to run
}

09.go

func main() {
    for i := 0; i < 3; i++ {
        j := i
        go func() {
            fmt.Println(j)
        }()
    }
    time.Sleep(time.Second) // Give goroutines time to run
}

10.go

func main() {
    people := []struct {
        Name string
        Age  int
    }{
        {"Alice", 23},
        {"Bob", 32},
        {"Charlie", 28},
    }

    sort.Slice(people, func(i, j int) bool {
        return people[i].Age < people[j].Age
    })

    fmt.Println(people)
}