Methods: Difference between revisions

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*Make your tables more dynamic
*Make your tables more dynamic


{{EmphasisBox|This tutorial-like section assumes you have a good knowledge of table terminology and {{type|function|3=functions}}.}}
{{EmphasisBox|This tutorial-like section assumes you have a good knowledge of table terminology and understand {{type|functions|3=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.
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.

Revision as of 01:04, 2 April 2012

Methods are unique functions which belong to a particular object or can be custom made. They are 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.

A method acts 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 understand 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 = 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)