Function scope

A function can be declared as local to limit the scope of the function. A function is global by default.

It's good practice to use local whenever possible to limit the scope of functions and variables to where they are needed. It allows for a flexible and modular approach in designing functions.

Example of a global function

If you were to create a simple APP.lua file and add a function called APPadd like below:

function APPadd(a,b)
   local sum = a + b
   return sum
end

In main you can then call APPadd and get the sum:

Example of a local function

In the same APP.lua file, now alter the function to be local.

local function APPadd(a,b)
   local sum = a + b
   return sum
end

return APPadd

Note: the function is now local, but we have also returned the APPadd function.

Now in main, you can capture the returned function in your require statement and use it.