My issue is I can’t do a calculation when I do print(“10+5/5”) , it will just print out “10+5/5”.
The numbers calculated is based on user input.
How do I make it so I can convert my string to perform calculation?
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You can wrap it a loadstring, but keep in mind only server scripts can use it and ServerScriptService.LoadStringEnabled has to be on.
print(loadstring("return 10 + 5/5")())
will get you the result.
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Maybe you can try to use tonumber().
Do you have any other way in mind without using loadstring? I’m afraid this will pose a security threat.
@Intencidy To number doesn’t work.
Another method is to use a dictionary storing functions:
--Translate string into mathematical expression
local prefixesFunctions = {
["/"] = function (number1,number2)
return number1/number2
end;
["-"] = function (number1,number2)
return number1 - number2
end;
["*"] = function (number1,number2)
return number1*number2
end;
["+"] = function (number1,number2)
return number1+number2
end;
}
From this other post, with a similar gui calculator project:
It won’t pose a security threat if you don’t trust the client by sandboxing properly. You just want to calculate expressions, so you wouldn’t really need any global environment.
The code I have so far is below. The buttons are named “Button1”, “Button2”, each corresponds to the number.
Please let me know how I can apply that dictionary into here.
for i,v in pairs (calculatorFrame:GetChildren()) do
if v:IsA("TextButton") then
v.MouseButton1Click:Connect(function()
local currentText = calculatorFrame.TextCalculation
local actionToDo = string.gsub(v.Name, "Button", "")
if tonumber(actionToDo) ~= nil then
currentText.Text = currentText.Text..tostring(actionToDo)
elseif actionToDo == "Plus" then
currentText.Text = currentText.Text.."+"
elseif actionToDo == "Minus" then
currentText.Text = currentText.Text.."-"
elseif actionToDo == "Multiply" then
-- if not string.find(
currentText.Text = currentText.Text.."*"
elseif actionToDo == "Divide" then
currentText.Text = currentText.Text.."/"
elseif actionToDo == "Calc" then -- calculate the whole string
end
end)
end
end
This might be helpful:
Thank you, but I’ve already looked into this.
Okay… did it not work or…? What do you need to do that loadstring or this module can’t cover?
I prefer not to use loadstring or modules, just a few lines of script if possible.
That is what loadstring can help you achieve, it’s not inherently dangerous.
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Do you have a link to the Roblox documentation page of loadstring? I couldn’t find anything. Thanks.
https://developer.roblox.com/en-us/api-reference/lua-docs/Lua-Globals
It only works server-side so exploiters can’t access it unless you have unsecure remote events
Sample using the parser:
local parser = require(5005473860)
local expression = parser.compile("9/3+7")
local result = parser.run(expression)
print(result) -- 10
--OR
print(parser.evaluate("asin(1)*2")) -- pi
Sample using loadstring:
local expression = "math.exp(1)"
local f = loadstring("return "..expression)
setfenv(f, {math = math}) -- IMPORTANT TO PREVENT CODE INJECTION
local result = f()
print(result) -- e
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Thanks, it works great. Does your paser thing have a documentation?
I got the code from here:
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Do you know how would I be able to find the square root and square number of x? I tried using ^ but it works like an addition, instead of exponent.
Unfortunately from reading through the source code it looks like the ^ symbol was only programmed in as a bitwise ‘xor’ operation. For exponents and square roots you would have to use pow(2, 3) and sqrt(9)