Lua - Couple Questions - lua

Im a amatuer at coding. So, mind me if i face palmed some things.
Anyways, im making a alpha phase for a OS im making right? I'm making my installer. Two questions. Can i get a code off of pastebin then have my lua script download it? Two. I put the "print" part of the code in cmd. I get "Illegal characters". I dont know what went wrong. Here's my code.
--Variables
Yes = True
No = False
--Loading Screen
print ("1")
sleep(0.5)
print("2")
sleep(0.5)
print("Dowloading OS")
sleep(2)
print("Done!")
sleep(0.2)
print("Would you like to open the OS?")
end

I see a few issues with your code.
First of all, True and False are both meaningless names - which, unless you have assigned something to them earlier, are both equal to nil. Therefore, your Yes and No variables are both set to nil as well. This isn't because true and false don't exist in lua - they're just in lowercase: true and false. Creating Yes and No variables is redundant and hard to read - just use true and false directly.
Second of all, if you're using standard lua downloaded from their website, sleep is not a valid function (although it is in the Roblox version of Lua, or so I've heard). Like uppercase True and False, sleep is nil by default, so calling it won't work. Depending on what you're running this on, you'll want to use either os.execute("sleep " .. number_of_seconds) if you're on a mac, or os.execute("timeout /t " .. number_of_seconds) if you're on a PC. You might want to wrap these up into a function
function my_sleep_mac(number_of_seconds)
os.execute("sleep " .. number_of_seconds)
end
function my_sleep_PC(number_of_seconds)
os.execute("timeout /t " .. number_of_seconds)
end
As for the specific error you're experiencing, I think it's due to your end statement as the end of your program. end in lua doesn't do exactly what you think it does - it doesn't specify the end of the program. Lua can figure out where the program ends just by looking to see if there's any text left in the file. What it can't figure out without you saying it is where various sub-blocks of code end, IE the branches of if statements, functions, etc. For example, suppose you write the code
print("checking x...")
if x == 2 then
print("x is 2")
print("Isn't it awesome that x is 2?")
print("x was checked")
lua has no way of knowing whether or not that last statement, printing the x was checked, is supposed to only happen if x is 2 or always. Consequently, you need to explicitly say when various sections of code end, for which you use end. For a file, though, it's unnecessary and actually causes an error. Here's the if statement with an end introduced
print("checking x...")
if x == 2 then
print("x is 2")
print("isn't it awesome that x is 2?")
end
print("x was checked")
although lua doesn't care, it's a very good idea to indent these sections of code so that you can tell at a glance where it starts and ends:
print("checking x...")
if x == 2 then
print("x is 2")
print("isn't it awesome that x is 2?")
end
print("x was checked")
with regards to your "pastebin" problem, you're going to have to be more specific.

You can implement sleep in OS-independent (but CPU-intensive) way:
local function sleep(seconds)
local t0 = os.clock()
repeat
until os.clock() - t0 >= seconds
end

Related

Fixing my color touch script for my roblox puzzle game

So I have a roblox puzzle game that I have been working on for a while now on based on the arcade classic Q bert where the goal is to change all the colours of the bricks while avoiding enemies and getting a high score but I will be adding some features of my own so it does not get as repetitive such as additional tasks like collecting keys on platforms to unlock the door to the next level and secrets like a diamond that rarely appears once every 10 rounds and collecting one gives the player an extra dude and 10 million points.
This is how the game looks so far https://streamable.com/na46cu
The issue I am having as you can see is that the colours do in fact change but when I jump on it again it changes back to the first colour it changes to which in this case is green but I want it to stay on the first colour and make it so that it does not change until the player jumps on the brick again and later on in the game I want it to become more complex and puzzle like as the game goes on like in this example [https://www.youtube.com/watch?v=9eXJWiNXpOo][2] .
I have tried a few things like adding timers ,debounces and even separate scripts alltogether none of which have worked out for me so far and I of course went out looking for a question from somebody else that had a similar problem but so far I have been struggling to find anybody else that has the same problem.
local module = {} --module for the modulescript and for loop is created
local CollectionService = game:GetService("CollectionService")
for _, part,brick in pairs (CollectionService:GetTagged("blocks"))
do
part.Touched:Connect(function(hit) --Part connects with the touched property to the function with the parameter hit
if (hit.Parent:FindFirstChild("Humanoid"))
then
part.BrickColor = BrickColor.new ("Bright green")
wait (2)
part.BrickColor = BrickColor.new ("Eggplant")
-- local sound = workspace.Sound -- use "local sound = workspace.Sound", if there is already a sound object in the workspace
--sound.SoundId = "rbxassetid://4797903038" --replace quoted text with whatever sound id you need to use
--sound:Play()
end
end)
end
-- end)
--end
return module
I am not the best programmer but I do know the basics of programming and I have tried out various programming languages like Python and c++ all of which are not all that hard to understand once you know the basics of it all but finding out the solution to the problem is the really tricky part and so is bug fixing and troubleshooting.
I do know I could try a simple debounce system but that still does not solve the problem and it only makes it so the code only runs once and slows it down.
I have been asking all over the place for a solution to this problem but I never got an answer to it so I am trying on good old Stackoverflow for once to see if this will be the place where I get the help I need.
this should work, try it
local module = {} --module for the modulescript and for loop is created
local CollectionService = game:GetService("CollectionService")
local DidParts = {} -- Initializing another table to check if the part is already in it
for _, part,brick in pairs(CollectionService:GetTagged("blocks")) do
part.Touched:Connect(function(hit) --Part connects with the touched property to the function with the parameter hit
if hit.Parent:FindFirstChild("Humanoid") then
if table.find(DidParts,part) then
return -- checking if the part isnt in the table if it is then return
end
part.BrickColor = BrickColor.new("Bright green")
wait(2)
part.BrickColor = BrickColor.new("Eggplant")
table.insert(DidParts,part) -- when all the code has finished insert it in the table
-- local sound = workspace.Sound -- use "local sound = workspace.Sound", if there is already a sound object in the workspace
--sound.SoundId = "rbxassetid://4797903038" --replace quoted text with whatever sound id you need to use
--sound:Play()
end
end)
end
-- end)
--end
return module

(Lua) How do I increment a variable every time one of three if statements runs?

I'm building a moving and sensing bot in CoppelliaSim for school. CopelliaSim uses Lua for scripting. Basically every time the bot's forward sensors hit something, one of three if statements will run. I want it to count how many times any of these if statements runs, and once that count gets to a certain amount (like 20), I'll run something else, which will do the same thing (find collisions, add to the count, reach an amount, and switch back to the first).
i=0
result=sim.readProximitySensor(noseSensor) -- Read the proximity sensor
-- If we detected something, we set the backward mode:
if (result>0) then backUntilTime=sim.getSimulationTime()+3
print("Collision Detected")
i=i+1
print(i)
end
result=sim.readProximitySensor(noseSensor0) -- Read the proximity sensor
-- If we detected something, we set the backward mode:
if (result>0) then backUntilTime=sim.getSimulationTime()+3
print("Collision Detected")
i=i+1
print(i)
end
result=sim.readProximitySensor(noseSensor1) -- Read the proximity sensor
-- If we detected something, we set the backward mode:
if (result>0) then backUntilTime=sim.getSimulationTime()+3
print("Collision Detected")
i=i+1
print(i)
end
Above is the start of a function and one of the three If statements. I'm printing just to see if it actually increments. It is printing, but it is not incrementing (just 1 over and over). This bot has 3 sensors on it (an if statement for each sensor) and it adds 1 to i for the first collision and ignores the rest, even if it's from the same sensor. I feel like my problem is just some simple syntax issue with Lua that I don't know and can't find how to properly fix.
I'm happy to provide more code if this little snippet was not sufficient to answer this question.
Assuming that you have a looping function such as sysCall_actuation which is being executed per simulation step. As Joseph Sible-Reinstate Monica has already stated, you are setting your variable i back to zero every time a simulation step is executed. To achieve your goal, you would have to set your variable to 0 outside your function. There are two appropriate approaches to achieve that:
Define the variable outside any function, in the beginning of your file (or before you define any function that uses your variable e.g right before the definition of sysCall_actuation).
-- Beginning of the file.
local i = 0
..
function sysCall_actuation()
..
i = i + 1
..
end
Define your variable in sysCall_init function, which is the appropriate approach in CoppeliaSim.
function sysCall_init()
i = 0
..
end
Finally, you can use your variable in your sysCall_actuation function with basic comparison operations:
function sysCall_actuation()
..
if i > 20 then
i = 0 -- Reset 'i' so this function will not be running every step again and again.
-- Do something here.
..
end
As a side note, practice using local variables whenever you can, to keep the memory clean and avoid having ambiguous variables.

Is there a reason why this code is not outputting a worth

Problem
Hello, StackOverflow community! I am working on this Lua game, and I was testing to see if it would change the text on my TextLabel to the Bitcoins current worth, I was utterly disappointed when nothing showed up.
I have tried to do research on Google, and my code seems to be just right.
Code
Change = false
updated = false
while Change[true] do --While change = true do
worth = math.random(1,4500) --Pick random number
print('Working!') --Say its working
Updated = true --Change the updated local var.
end --Ending while loop
script.Parent.TextLabel.Text.Text = 'Bitcoin is currently worth: ' .. worth
--Going to the Text, and changing in to a New worth.
while Updated[false] do --While updated = false do
wait(180) --Wait
Change = true --After waits 3 minutes it makes an event trigger
end -- Ending while loop
wait(180) --Wait
Updated = false --Reseting Script.
I expect the output on the Label to be a random number.
I can't really speak to roblox, but there are a couple of obvious problems with your code:
Case
You have confusion between capitalized ("Updated", "Change") and lowercase ("updated", "change" [in commented while statement]), which will fail. See, for example:
bj#bj-lt:~$ lua
Lua 5.2.4 Copyright (C) 1994-2015 Lua.org, PUC-Rio
> Updated = true
> print(Updated)
true
> print(updated)
nil
So be super-careful about what identifiers you capitalize. In general, most programmers leave variables like that in all-lowercase (or sometimes things like camelCase). I suppose there might be some oddball lua runtime out there that is case-insensitive, but I don't know of one.
Type misuse.
Updated is a boolean (a true/false value), so the syntax:
while Change[true] do
...is invalid. See:
> if Updated[true] then
>> print("foo")
>> end
stdin:1: attempt to index global 'Updated' (a boolean value)
stack traceback:
stdin:1: in main chunk
[C]: in ?
Note also that the "While change == true do" is also wrong because of case ("While" is not valid lua, but "while" is).
Lastly:
Lack of threading.
You have basically two different things that you're trying to do at once, namely randomly change the "worth" variable as fast as possible (it's in a loop) and see a set a label to match it (it looks like you probably want it to change constantly). This requires two threads of operation (one to change worth and another to read it and stick it on the label). You've written this like you're assuming you have a spreadsheet or something and that. What your code is actually doing is:
Setting some variables
Updating worth indefinitely, printing 'Working!' a bunch, and...
Never stopping
The rest of the code never runs, because the rest of the code isn't in a background thread (basically the first bit monopolizes the runtime and never yields to everything else).
Lastly, even if the top code was running in the background, you only set the Text label one-time to exactly "Bitcoin is currently worth: 3456" (or some similar number) one time. The way this is written there won't be any updates thereafter (and, if it runs once before the other thread has warmed up, it might not be set to anything useful at all).
My guess is that your runtime is spitting out errors left and right due to the identifier problems and/or is running in a tight infinite loop and never actually getting to the label refresh logic.
BJ Black has given an excellent description of the issues with the syntax, so I'll try to cover the Roblox piece of this. In order for this kind of thing to work properly in a Roblox game, here are some assumptions to double check :
Since we are working with a TextLabel, is it inside a ScreenGui? Or a SurfaceGui?
If it's in a ScreenGui, make sure that ScreenGui is in StarterGui, and is this code in a LocalScript
If it's in a SurfaceGui, make sure that SurfaceGui is adorning a Part and this code
is in a Script
After you checked all those pieces, maybe this is closer to what you were thinking :
-- define the variables we're working with
local textLabel = script.Parent.TextLabel
local worth = 0
-- create an infinite loop
spawn(function()
while true do
--Pick random number
worth = math.random(1,4500)
-- update the text of the label with the new worth
textLabel.Text = string.format("Bitcoin is currently worth: %d", worth)
-- wait for 3 minutes, then loop
wait(180)
end
end)
I removed Updated and Changed because all they were doing was deciding whether or not to change the value. The flow of your loop was:
do nothing and display an undefined number. Wait 3 minutes
update the number, display it, wait 6 minutes
repeat 1 and 2.
So hopefully this is a little clearer and closer to what you were thinking.

Roblox Anti-Exploit WalkSpeed Script

I am making a game that has different walkspeeds in different sections, but I don't want people to change their own walkspeed with hacks. My solution was to make a part and stretch it to fit the entire area and make it invisible + CanCollide disabled, and then use the child script to kill you if your walkspeed isn't what it should be:
script.Parent.Touched:connect(function(WSChecker)
if not WSChecker.Parent then return end
local humanoid = WSChecker.Parent:FindFirstChild("Humanoid")
if not humanoid then return end
if (humanoid.WalkSpeed ~= 25) then
humanoid.Health = 0
end
end)
Problem is that it does not work with multiple players in the part at one time, and I want to make it so it will kick the player instead of killing them. Is there a way to go about these problems? It has to check their ws only within the part, and I don't know how to make it kick whoever changed their ws instead of killing them.
I would suggest hooking up your function to each player's Humanoid instead, and use the Humanoid.Running event.
Humanoid.Running provides you the speed they're currently running at, which means you can check if that speed is ever above a certain threshold, and punish them if it is.
Code example:
player.Character.Humanoid.Running:Connect(function(Speed)
print(Player, "is running at speed", Speed)
end)
As for kicking, you want to use player:Kick().
if (humanoid.WalkSpeed ~= 25) then
game.Players.LocalPlayer:Kick()
end
that should do the trick...
I think I can help. The solution that worked for me is:
local player = game.Players.LocalPlayer --Make sure it's a local script.
local char = player.Character
local hum = char:WaitForChild("Humanoid")
local hum2 = char.Humanoid
script.Parent = game.StarterPlayer.StarterPlayerScripts
if hum.WalkSpeed >16 then
player:Kick('You have been kicked for possible speed hacks.')
end
if hum2.WalkSpeed >16 then
player:Kick('You have been kicked for possible speed hacks.')
end
if (humanoid.WalkSpeed ~= 25) then
game.localplayer.remove:fire
end
end)
Hopefully, this is a better solution.
You can ofcourse do the above but as an addition to what everyone above said, checking if the walkspeed value is at the desired value is easily bypassable.
Exploiters will get the raw metatable of the game and hook __index to return a normal value for WalkSpeed. Metatables cant be detected either as most modern exploits use C closures instead of Lua. Your best chance is to see how fast the character is moving and teleport them back if player is moving too fast (like a passive anticheat).

Evaluating a math string in Corona Lua

I would like to evaluate a math string in my corona app. Right now I'm focusing on the trig functions, so let's let the example be the most difficult we're likely to face:
local expr = "2sin(4pi+2)+7"
My goal is for this to somehow be (either) evaluated as is with maybe a pi --> math.pi switch, or to even break it up. The breaking up would be much more difficult, however, since it COULD be as complicated a above, but could also just be sin(1).
So I would prefer to stay as close to the python eval(expr) function as possible, but if that can't happen, I am flexible.
The simplest way would be to replace sin with math.sin (pi with math.pi and so on), add missing multiplications signs, and run it through loadstring, but loadstring is not available in Corona environment.
This means you will need to write your own parser for these expressions. I found a discussion on Corona forums that may help you as a starting point: here, with some details and a demo here
This should do the trick, it is able to use the lua math functions without putting 'math.function' so just sqrt(100) works fine. I threw this together because I have seen this question asked way too many times. Hopes this helps :)
If you have any questions feel free to contact me at rayaman99#gmail.com
function evaluate(cmd,v) -- this uses recursion to solve math equations
--[[ We break it into pieces and solve tiny pieces at a time then put them back together
Example of whats going on
Lets say we have "5+5+5+5+5"
First we get this:
5+5+5+5 + 5
5+5+5 + 5
5+5 + 5
5 + 5
Take all the single 5's and do their opperation which is addition in this case and get 25 as our answer
if you want to visually see this with a custom expression, uncomment the code below that says '--print(l,o,r)'
]]
v=v or 0
local count=0
local function helper(o,v,r)-- a local helper function to speed things up and keep the code smaller
if type(v)=="string" then
if v:find("%D") then
v=tonumber(math[v]) or tonumber(_G[v]) -- This section allows global variables and variables from math to be used feel free to add your own enviroments
end
end
if type(r)=="string" then
if r:find("%D") then
r=tonumber(math[r]) or tonumber(_G[r]) -- A mirror from above but this affects the other side of the equation
-- Think about it as '5+a' and 'a+5' This mirror allows me to tackle both sides of the expression
end
end
local r=tonumber(r) or 0
if o=="+" then -- where we handle different math opperators
return r+v
elseif o=="-" then
return r-v
elseif o=="/" then
return r/v
elseif o=="*" then
return r*v
elseif o=="^" then
return r^v
end
end
for i,v in pairs(math) do
cmd=cmd:gsub(i.."(%b())",function(a)
a=a:sub(2,-2)
if a:sub(1,1)=="-" then
a="0"..a
end
return v(evaluate(a))
end)
end
cmd=cmd:gsub("%b()",function(a)
return evaluate(a:sub(2,-2))
end)
for l,o,r in cmd:gmatch("(.*)([%+%^%-%*/])(.*)") do -- iteration this breaks the expression into managable parts, when adding pieces into
--print(":",l,o,r) -- uncomment this to see how it does its thing
count=count+1 -- keep track for certain conditions
if l:find("[%+%^%-%*/]") then -- if I find that the lefthand side of the expression contains lets keep breaking it apart
v=helper(o,r,evaluate(l,v))-- evaluate again and do the helper function
else
if count==1 then
v=helper(o,r,l) -- Case where an expression contains one mathematical opperator
end
end
end
if count==0 then return (tonumber(cmd) or tonumber(math[cmd]) or tonumber(_G[cmd])) end
-- you can add your own enviroments as well... I use math and _G
return v
end
a=5
print(evaluate("2+2+2*2")) -- This still has work when it comes to pemdas; however, the use parentheses can order things!
print(evaluate("2+2+(2*2)"))-- <-- As seen here
print(evaluate("sqrt(100)"))
print(evaluate("sqrt(100)+abs(-100)"))
print(evaluate("sqrt(100+44)"))
print(evaluate("sqrt(100+44)/2"))
print(evaluate("5^2"))
print(evaluate("a")) -- that we stored above
print(evaluate("pi")) -- math.pi
print(evaluate("pi*2")) -- math.pi

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