not a superset of flag: missing Func()

[muir]

As of Go 1.16, base "flag" now has:

func (f *FlagSet) Func(name, usage string, fn func(string) error)`

Please add for feature parity -- Func() is probably the best thing about the base "flag" package

[riadevatix]

Agreed. This one is missing. Hope they'll add this.

[avdb13]

Does anyone have a temporary workaround?

[hoshsadiq]

As a workaround you can use go's flag parser:

fs := pflag.NewFlagSet(os.Args[0], pflag.ExitOnError)
goflag.Func("flagname", "help message for flagname", func(string) error {
	fmt.Println("functioning")
	return nil
})
fs.AddGoFlagSet(goflag.CommandLine)
fs.Parse([]string{"--flagname", "123"})