Learning lua in an odd way

hello.lua

print("Hello World")
go_print("Hello from Go inside Lua")
print(test_str)

main.go

package main

import (
	"fmt"
	"github.com/Shopify/go-lua"
)

func goPrint(l *lua.State) int {
	n := l.Top()
	if n != 1{
		panic("expected 1 argument")
	}
	s := lua.CheckString(l, 1)
	fmt.Println(s)
	return 0
}

func main() {
	l := lua.NewState()
	lua.OpenLibraries(l)
	l.PushGoFunction(goPrint)
	l.SetGlobal("go_print")
	l.PushString("testing123")
	l.SetGlobal("test_str")
	if err := lua.DoFile(l, "hello.lua"); err != nil {
		panic(err)
	}
}