Flag command line parsing in golang

huangapple
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英文:

Flag command line parsing in golang

问题

我不确定我理解这个例子的推理（取自这里），也不知道它试图传达关于Go语言的什么信息：

  1. package main
  3. import (
  4.     "flag"
  5.     "fmt"
  6. )
  8. func main() {
  9.     f := flag.NewFlagSet("flag", flag.ExitOnError)
  10.     f.Bool("bool", false, "this is bool flag")
  11.     f.Int("int", 0, "this is int flag")
  13.     visitor := func(a *flag.Flag) {
  14.         fmt.Println(">", a.Name, "value=", a.Value)
  15.     }
  17.     fmt.Println("Visit()")
  18.     f.Visit(visitor)
  19.     fmt.Println("VisitAll()")
  20.     f.VisitAll(visitor)
  22.     // set flags
  23.     f.Parse([]string{"-bool", "-int", "100"})
  25.     fmt.Println("Visit() after Parse()")
  26.     f.Visit(visitor)
  27.     fmt.Println("VisitAll() after Parse()")
  28.     f.VisitAll(visitor)
  29. }

在他们的设置基础上添加一个类似于下面的内容：

  1. int_val := f.Get("int")

以获取命名参数似乎更有用。我对Go完全不熟悉，所以只是试图熟悉这门语言。

英文:

I'm not sure I understand the reasoning behind this example (taken from here), nor what it is trying to communicate about the Go language:

  1. package main
  3. import (
  4.     "flag"
  5.     "fmt"
  6. )
  8. func main() {
  9.     f := flag.NewFlagSet("flag", flag.ExitOnError)
  10.     f.Bool("bool", false, "this is bool flag")
  11.     f.Int("int", 0, "this is int flag")
  13.     visitor := func(a *flag.Flag) {
  14.         fmt.Println(">", a.Name, "value=", a.Value)
  15.     }
  17.     fmt.Println("Visit()")
  18.     f.Visit(visitor)
  19.     fmt.Println("VisitAll()")
  20.     f.VisitAll(visitor)
  22.     // set flags
  23.     f.Parse([]string{"-bool", "-int", "100"})
  25.     fmt.Println("Visit() after Parse()")
  26.     f.Visit(visitor)
  27.     fmt.Println("VisitAll() after Parse()")
  28.     f.VisitAll(visitor)
  29. }

Something along the lines of the setup they have but then adding a

  1. int_val := f.get("int")

to get the named argument would seem more useful. I'm completely new to Go, so just trying to get acquainted with the language.

答案1

得分: 57

这是一个使用flag包的复杂示例。通常情况下，标志是这样设置的：

  1. package main
  3. import "flag"
  5. // 注意，变量是指针类型
  6. var strFlag = flag.String("long-string", "", "描述")
  7. var boolFlag = flag.Bool("bool", false, "标志的描述")
  9. func init() {
  10.     // 使用短标志设置长标志的示例
  11.     flag.StringVar(strFlag, "s", "", "描述")
  12. }
  14. func main() {
  15.     flag.Parse()
  16.     println(*strFlag, *boolFlag)
  17. }
英文:

This is complicated example of using flag package. Typically flags set up this way:

  1. package main
  3. import "flag"
  5. // note, that variables are pointers
  6. var strFlag = flag.String("long-string", "", "Description")
  7. var boolFlag = flag.Bool("bool", false, "Description of flag")
  9. func init() {
  10.     // example with short version for long flag
  11.     flag.StringVar(strFlag, "s", "", "Description")
  12. }
  14. func main() {
  15.     flag.Parse()
  16.     println(*strFlag, *boolFlag)
  17. }

huangapple
  • 本文由 发表于 2013年11月4日 13:09:32
  • 转载请务必保留本文链接：https://go.coder-hub.com/19761963.html
  • command-line-arguments
  • go
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