Getting arg to work in a varag function in Lua 5.2 (integrated in Delphi)

Question

When using the Lua 5.2 API, the code below prints "nil"

function __debug(szName, ...)
    print(type(arg));
end

__debug("s", 1, 2, 3, 4);

But this code does work when using Lua 5.1, and prints "table"

Answer 1

If you are referring to vararg function, the arg table was deprecated already in Lua 5.1. In Lua 5.2, you can use table.pack to create arg if you need it:

function debug(name, ...)
    local arg = table.pack(...)
    print(name)
    for i=1,arg.n do
        print(i, arg[i])
    end
end

Answer 2

That's because arg has been deprecated since Lua 5.1. It only remained as a compatibility feature.

References: Lua 5.1 manual, unofficial LuaFaq

a workaround is using this line to generate a table called arg:

local arg={...}