If / Else / Elseif
In Castle rules, there is a response called "If a condition is met, run a response". Lua has if statements that work in the same way.
In this example, we check the Character's position and then update the text based on that. Try moving the Character to the left and right and see how the text changes.
As you can see, we check the position of the Character in two different ways.
We check roundedX == 0 first. == means that the values are equal. Notice that we have to call math.round on the number first, otherwise it'd be very hard to get the Character exactly at 0.
Next, we check roundedX > 0. This will trigger if roundedX is greater than 0. It will be true even if roundedX is 0.001.
Last, we just have else. That means that if the first two checks don't pass, we'll run this block. So this only happens when roundedX doesn't equal 0 and is not greater than 0. Which means that roundedX must be less than 0.
Other Operators
Lua has a few more similar operators:
~=checks if a value is not equal to another value. A lot of other programming languages use!=for this operator, so remember to use~=in Lua.<checks if a value is less than another value.>=checks if a value is greater than or equal to another value.<=checks if a value is less than or equal to another value.
Here is an example using ~=. When the actor moves too far horizontally, it destroys itself.