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How to use 'return' in function?

Asked by

DrPredablox 153

8 years ago

Edited 8 years ago

Please make your question title relevant to your question content. It should be a one-sentence summary in question form.

01local Fruittilium = game.Workspace.Fruittilium
02local Player = game.Players.LocalPlayer
03local Mouse = Player:GetMouse()
04Mouse.Button1Down:connect(function()
05    if Mouse.Target == Fruittilium then
06    print("you clicked it")
07    local Fruit = Fruittilium:Clone()
08    Fruit.Parent = game.Workspace
09    Fruit.Name = "A Copy of Fruittilium"
10         --  I want to return this 'vector3.new(Mouse.Hit.p)'
11end
12end)

So how do I use 'return' to return that value?

You can put a variable before you connect the even then assign the value when the event is fired. How / where will this value be used? User#5423 17 — 8y

Let me get you a full explanation once I'm st my desk lightpower26 399 — 8y

1 answer

Answered by

Link150 1355

8 years ago

Edited 8 years ago

Unfortunately, returning values from an event callback is possible, but useless.

This is because your callback function is being called by Roblox, who doesn't expect, or simply doesn't care whether you return values or not. It will just discard them.

Upvalues

Thankfully there is a way around this. What you can do instead is use "upvalues". That sounds like a whole new concept, but the truth is you've probably already used them before without knowing what they were called. Upvalues are variables that are declared prior to your function, in an upper scope. For example:

01local tool = script.Parent
02 
03local selection
04 
05 
06tool.Equipped:connect(function(mouse)
07    local user = tool.Parent
08 
09    mouse.Button1Down:connect(function()
10        -- 'selection' here is an upvalue, because it was declared
11        -- outside of the current function.
12        selection = mouse.Target
13 
14        -- Note that 'user' is also an upvalue here.
15    end)
16 
17    -- 'selection' is an upvalue in this scope as well.
18end)
19 
20game:GetService("UserInputService").InputBegan:connect(function(input, processed)
21    -- Destroy selection upon pressing the delete key on the keyboard.
22 
23    if not processed then
24        if input.KeyCode == Enum.KeyCode.Delete or
25        input.KeyCode == Enum.KeyCode.KeypadPeriod then
26            -- Make sure the selection exists.
27            if selection and not selection.Locked then
28                selection:Destroy()
29            end
30        end
31    end
32end)
 View all 32 lines...

Conclusion

By setting and getting upvalues from within your functions, you can send information around without having to rely on returning values.

Anyway, I hope this helped. If it did then please be sure to accept, and optionally upvote, my answer. It helps both of us. ;) If you need anything else, you need only ask.

How to use 'return' in function?

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