Question

Edit I got this working, I’m not sure if this is the right way to do it, but this is what works right now

I just started learning Lua, and I’m trying to figure out how to pass tables between files so that I can have a more organized codespace. I have read through the book Programming in Lua, and for some reason, I can’t figure out what i’m doing wrong.

The problem i’m getting is this error:

lua: Test2.lua:3: attempt to call method ‘New’ (a nil value)

From this code:

--Test.lua----------------
module("Test", package.seeall)
vector = require "./Hump/vector"

Bot = {}

Bot.position  =  vector.new(0,0)

function Bot:New(object)
    object = object or {}
    setmetatable(object, self)
    self.__index = self
    return object
end


--Test2.lua------------------
require "Test"

Bot1 = Test.Bot:New()

print(Bot1.position)

As far as I understand it, this error means that it cannot find the method new, it is effectively undefined. I thought that require imports the file in the path?

Answer 1

Bot is an empty table.

local B = {} -- initialize local B with new table
Bot = B -- Bot now references the same table as B

B = { position = vector.new(0,0) } -- here you create a NEW table, B ~= Bot now

function B:New(object) -- store New function in B table, Bot still empty

So you’re returning an empty table.

No need for two variables here at all.

local Bot = {
    -- stuff
}

function Bot:New(object)
    -- stuff
end

return Bot