How do I use parameters this way?

I cannot explain the inner workings of why this happens but you can check the lua manual.

This is my example of how I got it working, there may be better solutions:-

test = true -- this must not be a local variable or getfenv will not pick it up as we are checking for 0 (global)

function change(test)
    print(test) -- at the function level it returns false which is what we want
-- this shows the variable which are accessible from a global level
    for i, v in pairs(getfenv(0)) do
            print(i, " = ", v)
    end 

-- from the first print statement we can the assume that what test will do is set false = false as from my experience code will always use the same value for the same line of code 

-- now we can attempt to find the global variables in this script, I have not tested if this finds "_G" variables but we know the name of the variable is test so we can then use the name test as a global variable to assign the value false.
   getfenv(0)['test'] = test 
end

change(false)

print(test) --returns false

Hope this help.

Hello.

Whenever you set parameters for a function, you are setting local variables to be used within that code block.

The following two code blocks are equivalent:

function change(test)

    -- other code
    test = test
end

function change(...)
    local test = ...

    -- other code
    test = test
end

You are running into a scope problem. As I demonstrated in the second code block, whenever you set parameters for a function, you are creating local variables to be used inside of that function.

That means that when you call function change with a parameter named test, it creates a local variable named test, and will not access a variable of the same name outside of the code block's scope.

local test = true

function change(test)
    test = test -- This sets a local variable named test equal to itself
end

change(false)
print(test) --returns true

In your above function, the test that was declared first is not modified. However, if you change the naming scheme, it will modify the intended value:

local test = true

function change(testValue)
    test = testValue
end

change(false)
print(test) --returns false