Variadic arguments support in lua function

[yongman]

I want to know how to support variadic argument in a graceful way, my implement as follows:

let function_call = lua.create_async_function(move |_lua, (arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9): 
        (String, Option<String>, Option<String>, Option<String>, Option<String>, Option<String>, Option<String>, Option<String>, Option<String>)| {
            // package arguments(without cmd) to argv
            // argc maximum is 8
            let cmd_name = arg1.clone();
            let mut argv = vec![];
            if let Some(a2) = arg2.clone() {
                argv.push(a2);
                if let Some(a3) = arg3.clone() {
                    argv.push(a3);
                    if let Some(a4) = arg4.clone() {
                        argv.push(a4);
                        if let Some(a5) = arg5.clone() {
                            argv.push(a5);
                            if let Some(a6) = arg6.clone() {
                                argv.push(a6);
                                if let Some(a7) = arg7.clone() {
                                    argv.push(a7);
                                    if let Some(a8) = arg8.clone() {
                                        argv.push(a8);
                                        if let Some(a9) = arg9.clone() {
                                            argv.push(a9);
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }

In this way function can call in lua with argument number less than 9, but user may be calling with more arguments which is uncertain.
Is there a graceful way to handle this?

Thanks.

[khvzak]

https://docs.rs/mlua/latest/mlua/struct.Variadic.html

[yongman]

Sorry I have not noticed mlua already have variadic support.
Thanks for your reply.