Updated: 2017-07-15 17:11:29 CST +08

Golang Refactor by Label

Introduction

Labels are declared by labeled statements and are used in the “break”, “continue”, and “goto” statements. - “Label scopes”, The Go Programming Language Specification

Example

  • Traditional, use varible as a flag

    func main() {
    var sum int
    stop := false // set a flag
    for i := 0; i < 10; i++ {
        for j := 0; j < 10; j++ {
            sum = i * j
            if sum > 80 {
                stop = true // set flag to true for break outer loop
                break
            }
        }
        if stop {
            break
        }
    }
    fmt.Println(sum)
}

  • Refactor by Label

    func main() {
    var sum int
FirstLoop: // define a label
    for i := 0; i < 10; i++ {
        for j := 0; j < 10; j++ {
            sum = i * j
            if sum > 80 {
                break FirstLoop // break label scope
            }
        }
    }
    fmt.Println(sum)
}

Reference