// Try operator `?` with generic Result<T,E> (non-int Ok payload).
import Std::Io::{PrintLine};
import Std::Result::{Result, Result_NewOk, Result_NewErr};
import Std::String::{String_Eq};

func GetGreeting(name: String) -> Result<String, String> {
    if String_Eq(name, "") {
        return Result_NewErr<String, String>("empty name");
    }
    return Result_NewOk<String, String>("hello");
}

func Greet(name: String) -> Result<String, String> {
    let g: String = GetGreeting(name)?;
    return Result_NewOk<String, String>(g);
}

func Main() -> int {
    PrintLine("Try generic Result demo:");

    let ok: Result<String, String> = Greet("bux");
    if ok.tag == Result_Ok {
        PrintLine(ok.data.Ok_0);
    }

    let err: Result<String, String> = Greet("");
    if err.tag == Result_Err {
        PrintLine(err.data.Err_0);
    }

    return 0;
}