(v4) Placeholder for Func params

[tandr]

I have to handle some params with Func, but when help is displayed, it shows "FUNC" as placeholder, and there is no way (at least I have not found one) to modify or set it later.

[peterbourgon]

Can you give an example of what you mean?

FlagConfig includes a Placeholder param for this purpose. AddStruct also supports a placeholder: struct tag.

[tandr]

Below is an except from the code

lookup := map[string]string{		
      "comma":     ",",
      "colon":     ":",
// ...etc
}

delimAliases := strings.Split("colon,comma,eol,eol-dos,eol-mac,pipe,semi,semicolon,space,sql,tab", ",")
flags.FuncLong("sep", func(s string) error {
    if d, ok := lookup[s]; ok {
	s = d
     }
     options.Delimiter = []byte(s)
     return nil
}, "Fields separator. Accepts aliases "+strings.Join(delimAliases, ","))

help for this option gives me

      --sep FUNC                Fields separator. Accepts aliases as colon,comma,eol,eol-dos,eol-mac,pipe,semi,semicolon,space,sql,tab

FuncLong (or any Func) do not have param for a placeholder.

May I suggest actually to have a version of the func that accepts FlagConfig, or string that looks like a tag instead of last parameter "usage", and it will parse it normally?

[peterbourgon]

This seems more like an Enum than a Func?

[tandr]

Thank you I did not know about enum. But Func still needs a custom placeholder, am I right?

[peterbourgon]

Yes, you're right. I'll address that shortly. But for now, you can specify a placeholder by backtick-quoting a section of the usage string. See this example.