I want to make a callback in a module script that is fired in other scripts. For example:
-- Normal script waiting for callback
local equation_solver = require(game.ServerScriptService.EquationSolver)
local function graph_complete()
equation_solver.find_value(1)
end
equation_solver:OnGraphDone(graph_complete)
How would I go about something like this? I haven’t found anything online. Is it even possible? Look forward to seeing your responses, thanks.
Your code sample and explanation of what you’re looking for are slightly confusing (at least to me they are), but if you want to achieve something like this, I would recommend using a BindableEvent.
Within the table you return, you’ll have a key which is the name of the event and a value which references BindableEvent.Event. From here, other scripts can connect to the Event of BindableEvent and internally your functions would fire the BindableEvent along with any arguments.
This describes more of an event-based network, though is this about what you’re looking for?
Could you give me an example of what you mean?
Sure. The idea is that you’re using a BindableEvent to facilitate a signal-like backend. Just a reminder that this will not replicate unlike Roblox signals (sadly, because we do not have selective replication). As well, the syntax differs from your code sample in that it uses a dot over a colon.
-- From your ModuleScript:
local module = {}
module.eOnSomethingDone = Instance.new("BindableEvent")
module.OnSomethingDone = module.eOnSomethingDone.Event
function module:DoSomething()
print("Did something")
self.eOnSomethingDone:Fire("foo")
end
return module
-- From your other script:
local module = require(module)
local function onSomethingDone(result)
print(result)
end
module.OnSomethingDone:Connect(onSomethingDone)
Thank you, I will try this out and get back to you. I think this is exactly what I was looking for.
Ok I get the idea of it and why it should work but for some reason it doesn’t. Here’s my module (I return it in equation:draw() after the for loop is done):
local equation = {}
equation.OnGraphDoneEvent = Instance.new("BindableEvent")
equation.OnGraphDone = equation.OnGraphDoneEvent.Event
local Settings = {
["EquationType"] = {
["Linear"] = "linear",
["Quadratic"] = "quadratic",
["Sin"] = "sin"
}
}
function equation:solve_bc(n1, n2, n_1, n_2)
local difference = n2 - n1
local approx = n1 - difference
local b = difference
local c = approx
return b, c
end
function equation:find_value(value)
local equation_graph = game.Workspace.EquationGraph
for i,v in pairs(equation_graph:GetChildren()) do
if v:IsA("Part") then
if v.Position.Y == value then
local beam_node = Instance.new("Part")
beam_node.Size = Vector3.new(1, 1000, 1)
beam_node.BrickColor = BrickColor.new("Bright red")
beam_node.Position = v.Position
beam_node.Anchored = true
beam_node.Parent = equation_graph
end
end
end
end
function equation:draw(equation)
local equation_graph = game.Workspace.EquationGraph
for i,v in pairs(equation_graph:GetChildren()) do
if v:IsA("Part") then
v:Destroy()
end
end
if equation[1] == Settings.EquationType.Linear then
for i = -10, 10, 0.1 do
local new_node = Instance.new("Part")
new_node.Size = Vector3.new(1,1,1)
new_node.Anchored = true
local x = (i)
local y = ((i * equation[2]) + equation[3])
new_node.Position = Vector3.new(x, y, 0)
new_node.Parent = equation_graph
end
self.OnGraphDoneEvent:Fire()
elseif equation[1] == Settings.EquationType.Quadratic then
for i = -10, 10, 0.1 do
local new_node = Instance.new("Part")
new_node.Size = Vector3.new(1,1,1)
new_node.Anchored = true
local x = (i)
local y = (((i^2) * equation[2]) + (i * equation[3]) + equation[4])
print(x, y)
new_node.Position = Vector3.new(x, y, 0)
new_node.Parent = equation_graph
end
self.OnGraphDoneEvent:Fire()
elseif equation[1] == Settings.EquationType.Sin then
for i = equation[2], equation[3], 0.5 do
local new_node = Instance.new("Part")
new_node.Size = Vector3.new(1,1,1)
new_node.Anchored = true
local x = (i)
local y = math.ceil(math.floor(math.sin(i * math.pi/180) * equation[4] * 100000)/100000 * 1000)/1000
print(x, y)
new_node.Position = Vector3.new(x, y, 0)
new_node.Parent = equation_graph
end
self.OnGraphDoneEvent:Fire("foo")
end
end
function equation:solve(equation_type, n1, n2, n3)
if equation_type == Settings.EquationType.Linear then
local difference = n2 - n1
local approx = n1 - difference
local plus_or_minus = nil
if approx < 0 then
plus_or_minus = ""
else
plus_or_minus = "+"
end
return {equation_type, difference, approx}
elseif equation_type == Settings.EquationType.Quadratic then
local difference_1 = n2 - n1
local difference_2 = n3 - n2
local a = (difference_2 - difference_1)/2
local n_1 = a * 1^2
local n_2 = a * 2^2
local term_1 = n1 - n_1
local term_2 = n2 - n_2
local b, c = equation.solve_bc(term_1, term_2, n1, n2)
local pom_b = ""
local pom_c = ""
if b > 0 then
pom_b = "+"
end
if c > 0 then
pom_c = "+"
end
return {equation_type, a, b, c}
end
end
return equation
This is the script:
local equation_solver = require(game.ServerScriptService.EquationModule)
--[[
equation_solver.solve("linear", 1, 2),
equation_solver.solve("linear", 7, 15),
equation_solver.solve("linear", 6, 9),
equation_solver.solve("quadratic", 7, 9, 12),
equation_solver.solve("quadratic", 1, 2, 4),
{"sin", -180, 180, 10},
{"sin", -180, 180, 3},
{"sin", -180, 180, 5},
{"sin", -180, 180, 100}
]]--
wait(5)
local equations = {
{"sin", -180, 180, 1},
}
local function solve_equation(result)
print(result)
end
for i,v in pairs(equations) do
print(table.concat(v, " "))
equation_solver:draw(v)
end
equation_solver.OnGraphDone:Connect(solve_equation)
After fiddling around with the ModuleScript a bit and both some print work and small reconfigurations, I noticed something: the issue you’re facing here is the time of arrival of these events.
Remember that Lua is single-threaded and runs sequentially. In your case, what’s happening is that you’re connecting to the event after the for loop runs. It connects after the loop runs and the signal fires, so the listener doesn’t ever get to handle the value.
Simply move your event connection below solve_equation to resolve the issue.
local function solve_equation(result)
print(result)
end
equation_solver.OnGraphDone:Connect(solve_equation)
-- For loop here
Oh wow that really was the problem, it works perfectly now. Thank you so much!