Go标志用法说明包含单词”value”。

huangapple
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英文:

Go Flag Usage Description Contains the Word value

问题

我已经定义了一个自定义标志，用于接受字符串切片，代码如下：

  1. type strSliceFlag []string
  3. func (i *strSliceFlag) String() string {
  4. 	return fmt.Sprint(*i)
  5. }
  7. func (i *strSliceFlag) Set(value string) error {
  8. 	*i = append(*i, value)
  9. 	return nil
  10. }

然后我使用以下代码进行解析：

  1.     ...
  2. 	var tags strSliceFlag
  3. 	flag.Var(&tags, "t", tFlagExpl)
  4. 	flag.Parse()
  5.     ...

当我构建这个程序并使用帮助标志运行它时：main -h，它会打印出：

  1. Usage of main:
  2.   -t value
  3.         Test explanation

我的问题是，value这个词是从哪里来的？我找不到如何删除它的方法。我认为这可能与标志的默认值有关。

英文:

I've defined a custom flag for accepting a slice of strings as such:

  1. type strSliceFlag []string
  3. func (i *strSliceFlag) String() string {
  4. 	return fmt.Sprint(*i)
  5. }
  7. func (i *strSliceFlag) Set(value string) error {
  8. 	*i = append(*i, value)
  9. 	return nil
  10. }

I then parse it with

  1.     ...
  2. 	var tags strSliceFlag
  3. 	flag.Var(&tags, "t", tFlagExpl)
  4. 	flag.Parse()
  5.     ...

When I build this program, and run it with the help flag: main -h, it prints out:

  1. Usage of main:
  2.   -t value
  3.         Test explanation

My question is, where is the word value coming from? I can't find out how to remove it. I think it maybe has something to do with the default value for the flag.

答案1

得分: 1

value是flag.UnquoteUsage为自定义类型选择的默认参数名称（通过flag.(*FlagSet).PrintDefaults呈现）。

您可以使用反引号覆盖默认值在您的用法文本中。反引号将从用法文本中删除。例如：

  1. package main
  3. import (
  4. 	"flag"
  5. 	"fmt"
  6. )
  8. type stringSlice []string
  10. func (s *stringSlice) String() string {
  11. 	return fmt.Sprint(*s)
  12. }
  14. func (s *stringSlice) Set(v string) error {
  15. 	*s = append(*s, v)
  16. 	return nil
  17. }
  19. func main() {
  20. 	var s stringSlice
  21. 	flag.Var(&s, "foo", "append a foo to the list")
  22. 	flag.Var(&s, "foo2", "append a `foo` to the list")
  23. 	flag.Parse()
  24. }

使用-h运行将显示参数名称的更改：

  1. Usage of ./flagusage:
  2.   -foo value
  3.     	append a foo to the list
  4.   -foo2 foo
  5.     	append a foo to the list
英文:

value is the default argument name chosen by flag.UnquoteUsage for custom types (rendered via flag.(*FlagSet).PrintDefaults).

You can override the default with backquotes in your usage text. The backquotes are stripped from usage text. Eg:

  1. package main
  3. import (
  4. 	"flag"
  5. 	"fmt"
  6. )
  8. type stringSlice []string
  10. func (s *stringSlice) String() string {
  11. 	return fmt.Sprint(*s)
  12. }
  14. func (s *stringSlice) Set(v string) error {
  15. 	*s = append(*s, v)
  16. 	return nil
  17. }
  19. func main() {
  20. 	var s stringSlice
  21. 	flag.Var(&s, "foo", "append a foo to the list")
  22. 	flag.Var(&s, "foo2", "append a `foo` to the list")
  23. 	flag.Parse()
  24. }

Running with -h shows how the argument name changes:

  1. Usage of ./flagusage:
  2.   -foo value
  3.     	append a foo to the list
  4.   -foo2 foo
  5.     	append a foo to the list

huangapple
  • 本文由 发表于 2022年4月9日 19:05:30
  • 转载请务必保留本文链接：https://go.coder-hub.com/71807493.html
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