Call an object method from a string

Question

I have a main loop in my lua script, and i am including 2 objects like this:

local Menu = require("menu")
local InputHandler = require("inputhandler")

Here are the scripts for each object:

menu.lua

Menu = {
  Active = false,
  Initialise = function(self)
  end,
  ToggleMenu = function(self)
    self.Active = not self.Active
    print(self.Active)
  end
}
return Menu

and inputhandler.lua

InputHandler = {
  KeyBinds = {
    q = { scancode = 16, bind = "q", action = "Menu:ToggleMenu" }
  },
  RunKeyAction = function (self, key)
    for k, v in pairs(self.KeyBinds) do
      if (v.bind == key) then
        _G[v.action]()
      end
    end
  end
}
return InputHandler

Basically I am trying to map keyboard keys to various functions within my script, so when someone presses "Q", it will run the method associated with that key.

So if I do something like this:

InputHandler:RunKeyAction("q")

It will run this method:

Menu:ToggleMenu()

When I run this script as it is now, I get this error:

lua: ./classes//inputhandler.lua:8: attempt to call field '?' (a nil value)
stack traceback:
    ./classes//inputhandler.lua:8: in function 'RunKeyAction'
    [string "<eval>"]:20: in main chunk

Can anyone please tell me that correct way of doing this?

Thank you for reading

lhf · Accepted Answer · 2019-05-22 15:58:51Z

2

Use

q = { scancode = 16, bind = "q", action = Menu.ToggleMenu }

and

v:action()

answered May 22, 2019 at 15:58

lhf

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2 Comments

Aaranihlus Over a year ago

hello lhf, thanks a lot for your reply, i get this error when i try it that way: inputhandler.lua:4: attempt to index global 'Menu' (a nil value)

Mike V. Over a year ago

@Aaranihlus but you need to remember that state Active written in table q.Active instead Menu.Active ;-)

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