Discussion on: A pragmatic approach to shell completion

[Peter]

I started writing a export function but my lacking knowledge of go stopped me..
So thanks I will try out your export function instead :)

But just because I'm curious what did I do wrong here?

type Element struct {
    Type  string `json:"type"`
    Use   string `json:"user"`
    Short string `json:"short"`
    Long  string `json:"long"`

    Name      string `json:"name"`
    Shorthand string `json:"shorthand"`
    Usage     string `json:"usage"`

    Elements []Element `json:"elements"`
}

Run: func(cmd *cobra.Command, args []string) {
    var rootElement = Element{Type: "root", Use: cmd.Use, Short: cmd.Short, Long: cmd.Long}

    for _, c := range cmd.Commands() {
        var commandElement = Element{Type: "command", Use: c.Use, Short: c.Short, Long: c.Long}
        rootElement.Elements = append(rootElement.Elements, commandElement)
        c.LocalFlags().VisitAll(func(f *pflag.Flag) {
            var flagElement = Element{Type: f.Value.Type(), Name: f.Name, Shorthand: f.Shorthand, Usage: f.Usage}
            commandElement.Elements = append(commandElement.Elements, flagElement)
        })
    }
    bytes, err := json.Marshal(rootElement)
    if err != nil {
        fmt.Printf("Error: %s", err)
    }
    fmt.Println(string(bytes))
},

my rootElement is correct it has all the command elements as expected, but my commandElements have lost all their flags? they are there while inside c.LocalFlags().VisitAll( but when I get to bytes, err := json.Marshal(rootElement) they are gone?

[rsteube]

Not too sure with only a quick view on it, but my first guess would be that it's probably the difference of a *Element reference to a Element copy.
Meaning you are altering command.Element but rootElement.Elements might contain a different object.
Try putting rootElement.Elements = append(rootElement.Elements, commandElement) after the VisitAll.

[Peter]

Thanks for your help I managed to get a export running after finding the carapace-bin repo!!

[rsteube]

Ah yes, might get a bit lost in the text. For everyone else: github.com/rsteube/carapace-bin

[Peter]

After thinking about my go issue i think you are right, when i added the command element to the root command, it took a copy of my variable and stored it.
So all the changes i did after got lost. Not that it matters your solution was much better than mine :).