Methods

Methods are unique functions which belong to a particular object or can be custom made. Although standard Lua doesn't have them, they're a major focus of Roblox Lua. Some common examples of methods include 'Destroy()', 'Clone()', and 'FindFirstChild()'. You can find a full list of methods here.

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 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.

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)