Seven months later and I’m back with this problem again. What I did in the reply above was very messy, so I thought hey, why not bump this topic instead of creating a new one.
Today I tried making a spring module but the metatables didn’t work. Again. So I just straight up took the code from one of EgoMoose’s tutorials and it didn’t work aswell. I literally no idea what I’m doing wrong.
Error: ReplicatedStorage.Modules.Shared.Spring:17: attempt to perform arithmetic (sub) on nil - Spring:17 - I checked and self is only a table of the functions in the module.
ModuleScript (Spring)
local spring = {}
spring.__index = spring
function spring.new(position, velocity, target)
local self = setmetatable({}, spring)
self.position = position
self.velocity = velocity
self.target = target
self.k = 1
self.friction = 1
return self
end
function spring:update()
local d = (self.target - self.position)
local f = d * self.k
self.velocity = (self.velocity * (1 - self.friction)) + f
self.position += self.velocity
end
return spring
ServerScript
local springModule = require(game:GetService("ReplicatedStorage").Modules.Shared.Spring)
local spring = springModule.new(workspace.Part1.Position, 1, workspace.Part2.Position)
game:GetService("RunService").Stepped:Connect(function()
spring.target = workspace.Part2.Position
springModule:update()
workspace.Part1.Position = spring.position
end)
Old Topic
I am trying to make self a variable across the entire ModuleScript, but (see last function) self is nil.
local handler = {}
local mt = {__index = handler}
function handler.new() -- fired when the player enters (from a LocalScript)
local self = {}
self.aiming = false
return setmetatable(self, mt)
end
function handler:aim()
print(self.aiming) --> prints nil
end
I already tried asking this on Discord and Reddit, but got no reply, and also tried looking on the Developer Hub and even copying the examples one by one and it still didn’t work
Disclaimer: I have no idea if I am actually making sense or if that’s even how metatables work, but I’ve seen some open source code that does exactly what I am doing and works. Please excuse me if this is a stupid question.
local HandlerClass = {}
local HandlerInstanceMT = {
__index = HandlerClass
}
function HandlerClass.New()
local self = {}
self.aiming = false
return setmetatable(self, HandlerInstanceMT)
end
function HandlerClass:Aim()
print(self.aiming)
end
local handler = HandlerClass.New()
handler:Aim() --prints "false"
I don’t know why yours doesn’t, can’t spot any differences. Are you calling the methods properly? Try printing the object you get back from Class.New, and also print “self” in the :aim method. They should be the same, if they’re not then that explains why self.aiming might be nil.
I wanted to try and step through your code, inspecting variables at different points in time, but since your code isn’t in a working state I can’t do that.
I’m stumped I thought maybe you were overwriting the .aiming member to be nil, but doesn’t seem like it.
local Handler = {}
Handler.__index = Handler
function Handler.new()
local self = setmetatable({}, Handler)
self.Aiming = false
return self
end
function Handler:Aim()
print(self.Aiming)
end
return Handler
I have no idea why, but I fixed it by setting up the metatable in handler.new and adding all of the variables in a different function (handler.setupTable).
Seven months later and I’m back with this problem again. What I did in the reply above was very messy, so I thought hey, why not bump this topic instead of creating a new one.
Today I tried making a spring module but the metatables didn’t work. Again. So I just straight up took the code from one of EgoMoose’s tutorials and it didn’t work aswell. I literally have no idea what I’m doing wrong.
Error: ReplicatedStorage.Modules.Shared.Spring:17: attempt to perform arithmetic (sub) on nil - Spring:17 - I checked and self is only a table of the functions in the module.
ModuleScript (Spring)
local spring = {}
spring.__index = spring
function spring.new(position, velocity, target)
local self = setmetatable({}, spring)
self.position = position
self.velocity = velocity
self.target = target
self.k = 1
self.friction = 1
return self
end
function spring:update()
local d = (self.target - self.position)
local f = d * self.k
self.velocity = (self.velocity * (1 - self.friction)) + f
self.position += self.velocity
end
return spring
ServerScript
local springModule = require(game:GetService("ReplicatedStorage").Modules.Shared.Spring)
local spring = springModule.new(workspace.Part1.Position, 1, workspace.Part2.Position)
game:GetService("RunService").Stepped:Connect(function()
spring.target = workspace.Part2.Position
springModule:update()
workspace.Part1.Position = spring.position
end)
You store the position, velocity and other values in the spring object (variable spring in the server script). This means that the values are not stored inside the spring class. They are stored inside the spring object, so instead of springModule:Update() you should have spring:Update(). The object inherits the :Update() method from the class.
I thought maybe you were overwriting the .aiming member to be nil, but doesn’t seem like it.