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Version: latest - a1.19.x βš–οΈ

Extending Classes

How to extend nanos world Classes, nanos world provides a built-in way of extending and customizing the Classes

caution

This feature is still experimental, you can try it out and provide feedback before it's full release!

caution

Extending Classes can be very useful and speed up the development. Although the code may become very complex and hard for newcomers to understand. As it will start using non-documented methods and accessors.

Adding new Methods​

Adding new methods for classes is the most straightforward way, let's say we want to add a new method for Player, we just do that:

function Player:AddScore(score)
self:SetValue("score", self:GetValue("score", 0) + score)
end
tip

Within your methods, you can access the called entity instance with self.

And then you are able to call it as usual:

local my_player = GetPlayerSomehow()
my_player:AddScore(10)
tip

Extending Classes will have effect only on the Package and the side you are! You can define all new methods in the Shared folder to have it applied on both Client and Server!

Overriding Existing Methods​

Besides creating new methods, it's possible to override existing ones, for that, just redefine them:

function Character:SetLocation(new_location)
-- ... Do something
end

And you can call a special method called :Super() to call the original method as well:

function Character:SetLocation(new_location)
-- ... Do something
self:Super(new_location + Vector(1, 2, 3))
end

Overriding __newindex​

It is also possible to add a custom __newindex metamethod on Classes.

tip

__newindex metamethod is a function which is triggered when you attempt to set a value in an entity. E.g.: my_prop.something = 123.

For that, we just add a custom method called newindex:

function Player:newindex(key, value)
Package.Log("Setting a %s value: %s = %s", tostring(self), key, tostring(value))
end

An useful way of using __newindex is overriding it to SetValue automatically:

function Player:newindex(key, value)
self:SetValue(key, value)
end

local my_player = GetPlayerSomehow()
my_player.amazing_value = 123

Overriding __index​

tip

__index metamethod is a function which is triggered when you attempt to get a value from an entity. E.g.: local value = my_prop.something.

For that, we just add a custom method called index:

function Player:index(key)
Package.Log("Getting %s value: %s", tostring(self), key)
-- ... do something
return some_value
end

An useful way of using __index is overriding it to GetValue automatically:

function Player:index(key)
return self:GetValue(key)
end

local my_player = GetPlayerSomehow()
local amazing_value = my_player.amazing_value