Method

Methods are functions which belong to a particular object. Although standard Lua doesn't have them, they're a major focus of Roblox Lua. Methods act like a function stored within an object. The method itself is accessed in the same way a Function in a Table is accessed. However, a special property of methods changes how they are called.

These two lines of code are equivalent, calling the function a with the parameter <a>b.

b.a(b) 
b:a()

The second is briefer and more concise. Methods can increase typing speed, because there is less need to retype variable names.

Examples

All instances, possibly excluding some core services, have the remove method, along with the clone method. Sounds have the Play method and the Stop method.

Making your own

Making your own methods can

• Make your code look cool
• Make your tables more dynamic

This tutorial-like section assumes you have a good knowledge of table terminology and functions.

First, we need a table to apply the method to. I'm going to make a checkbox. It doesn't actually do anything, but it's an application example. Feel free to make this work.

Checkbox = {
    Checked = false,
    CheckedImage = "Image",
    UncheckedImage = "Image",
    ImageButton = ...,
    ChangeState = function(self)
        self.Checked = not self.Checked
    end
}
Checkbox.ImageButton.MouseButton1Down:connect(function()
    Checkbox:ChangeState()
end)

You might think you could type

Checkbox.ImageButton.MouseButton1Down:connect(Checkbox.ChangeState)

However, that would call Checkbox.ChangeState(x, y) when the event fired. We need to call Checkbox.ChangeState(Checkbox).

When you call a function as a method, you automatically pass an argument as the TABLE ITSELF. For example,

function ReturnTable(Num)
    return {
        Num, 
        PrintNum = function(self) 
            print(self.Num) 
        end
    }
end

Tabl = ReturnTable(5)
Tabl:PrintNum()

That will output 5 because we passed in the table, so the function will receive the table it's located in. Because we called it as a method, it passed "Tabl" as an argument. You can do it with a dot, but it looks kind of stupid:

Tabl.PrintNum(Tabl)